Document:

<PAGE>

                                                                   EXHIBIT 10.71

                   DEED OF TRUST WITH CARDINAL PARAGON, INC.
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

                                 Deed of Trust

                                     Terms

Date:     December 21, 2000

Grantor:  WELLS OPERATING PARTNERSHIP, L.P., a Delaware limited partnership

Grantor's Mailing Address:    c/o Wells Capital, Inc.
                              Attn: Mary Anna Raburn
                              6200 The Corners Parkway, Suite 250
                              Norcross, Gwinnett County, Georgia 30092

Trustee:                      REPUBLIC TITLE INSURANCE COMPANY, a Texas
                              corporation

Trustee's Mailing Address:    2626 Howell, 10/th/ Floor
                              Dallas, Dallas County, Texas 75204

Lender:                       CARDINAL PARAGON, INC., a Texas corporation

Lender's Mailing Address:     Attn: Mr. Gil J. Besing
                              8411 Preston Road, Suite 850
                              Dallas, Dallas County, Texas 75225

Note

     Date:     Dated as of the date hereof

     Original principal amount:     Three Million Dollars ($3,000,000.00)

     Borrower: WELLS OPERATING PARTNERSHIP, L.P.

     Lender:   CARDINAL PARAGON, INC.

     Maturity date: The earlier to occur of (i) the satisfaction in full of the
     obligations secured by the Prior Lien (as hereinafter defined), or (ii) the
     date that is six (6) months subsequent to the date hereof

Property (including any improvements):

          (a)  all that tract or parcel of land (the "Land") located in Houston,
     Harris County, Texas, being more particularly described on Exhibit A
                                                                ---------
     hereto; and
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

            (b)  all rights, privileges, and easements appurtenant to the Land,
     including any water rights, mineral rights, reversions, or other
     appurtenances to said Land, if any, and all right, title, and interest of
     Grantor, if any, in and to any land lying in the bed of any street, road,
     alley, or right-of-way, open or proposed, adjacent to or abutting the Land;
     and

            (c)  all buildings, structures, and improvements situated on the
     Land, and other amenities located on the Land, and all apparatus, built-in
     appliances, equipment, pumps, machinery, plumbing, heating, air
     conditioning, electrical and other fixtures located on the Land and not
     owned by tenants of the building (all of which, but exclusive of property
     owned by tenants of the building, are herein collectively referred to as
     the "Improvements"); and

            (d)  all personal property, if any, of Grantor and located on or to
     be located on or in, or used in connection with, the Land and Improvements
     ("Personal Property"); and

            (e)  all of Grantor's right, title, and interest, as landlord or
     lessor, in and to all leases that affect the Land and Improvements; and

            (f)  all of Grantor's right, title, and interest in and to any
     intangible property relating to and reasonably required for the ownership
     and operation of the Property, including, without limitation, building
     plans and specifications with respect to the Improvements, licenses and
     entitlements (e.g. certificates of occupancy), soil reports, surveys,
     warranties, guarantees, utility contracts, permits and any other rights
     acquired by Grantor and related to the ownership of or use and operation of
     the Land, Personal Property, or Improvements, if any (herein, the
     "Intangible Property").

Prior Lien: Deed of Trust dated as of the date hereof by Grantor for the benefit
            of Guaranty Federal Bank, F.S.B., 8333 Douglas Avenue, Dallas,
            Dallas County, Texas 75225, Attention: John Fainter, recorded in the
            Office of the Harris County Clerk, Texas, immediately prior to the
            recording of this deed of trust, which Deed of Trust for the benefit
            of Guaranty Federal Bank, F.S.B. secures the original principal sum
            of Thirty-Five Million, Nine Hundred Thousand and 00/100 Dollars
            ($35,900,000.00)

Other Exceptions to Conveyance and Warranty: See list of Other Exceptions to
Conveyance and Warranty set forth on Exhibit B attached hereto and made a part
                                     ---------
hereof

For value received and to secure payment of the Note, Grantor conveys the
Property to Trustee in trust. Grantor warrants and agrees to defend the title to
the Property, subject to the Prior Lien and the Other Exceptions to Conveyance
and Warranty. On payment of the Note and all other amounts secured by this deed
of trust, this deed of trust will have no further effect, and Lender will
release it at Grantor's expense.

                                       2
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

Clauses and Covenants

A.   Grantor's Obligations

Grantor agrees to--

1.   keep the Property in good repair and condition;

2.   pay all taxes and assessments on the Property before delinquency;

3.   defend title to the Property subject to the Prior Lien and the Other
Exceptions to Conveyance and Warranty and preserve the lien's priority as it is
established in this deed of trust;

4.   maintain or cause to be maintained, in a form acceptable to Lender, but
subject to the rights of the holder of the Prior Lien, an insurance policy
that--

     a.   covers all improvements for their full insurable value as determined
when the policy is issued and renewed, unless Lender approves a smaller amount
in writing;

     b.   contains an 80 percent coinsurance clause;

     c.   provides fire and extended coverage, including windstorm coverage;

     d.   protects Lender with a standard mortgage clause;

     e.   provides flood insurance at any time the Property is in a flood hazard
area; and

     f.   contains such other coverage as Lender may reasonably require;

5.   comply at all times with the requirements of the 80 percent coinsurance
clause;

6.   deliver to Lender the certificate of insurance with respect to the
insurance policy that Grantor is required to maintain hereunder no later than on
the date of the deed of trust and deliver renewals to Lender at least fifteen
days before expiration;

7.   obey all laws, ordinances, and restrictive covenants applicable to the
Property;

8.   keep any buildings occupied as required by the insurance policy; and

9.   pay or cause to be paid the Prior Lien notes and abide by or cause to be
abided by all Prior Lien instruments.

B.   Lender's Rights

                                       3
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

1.   Lender may appoint in writing a substitute trustee, succeeding to all
rights and responsibilities of Trustee.

2.   If the proceeds of the Note are used to pay any debt secured by prior
liens, Lender is subrogated to all the rights and liens of the holders of any
debt so paid.

3.   If the holder of the Prior Lien applies any proceeds it receives under the
insurance policy to repair or replace damaged or destroyed improvements covered
by the policy, Lender shall do the same with any proceeds it receives under the
insurance policy.  Otherwise, but subject to the rights of the holder of the
Prior Lien, Lender may apply any proceeds received under the insurance policy
either to reduce the Note or to repair or replace damaged or destroyed
improvements covered by the policy. If the Property is Grantor's primary
residence and Lender reasonably determines that repairs to the improvements are
economically feasible, Lender will make the insurance proceeds available to
Grantor for repairs.

4.   Notwithstanding note terms to the contrary, and unless applicable law
prohibits, all payments received by Lender from Grantor under the Note or this
deed of trust may, at Lender's discretion, be applied first to amounts payable
under this deed of trust and then to amounts due and payable to Lender under the
Note, to be applied to late charges, principal, or interest in the order Lender
in its discretion determines.

5.   If Grantor fails to perform any of Grantor's obligations, Lender may,
subject to the rights of the holder of the Prior Lien, perform those obligations
and be reimbursed by Grantor on demand for any amounts so paid, including
attorney's fees, plus interest on those amounts from the dates of payment at the
rate stated in the Note for matured, unpaid amounts. The amount to be reimbursed
will be secured by this deed of trust.

6.   If there is a default on the Note after a grace period of five (5) days to
cure such default, or if Grantor fails to perform any of Grantor's obligations
after a grace period of ten (10) days to cure such default, except with respect
to uncured defaults under the Prior Lien and defaults with respect to Grantor's
obligation maintain, or cause to be maintained, an insurance policy as required
hereunder, for which no cure period is allowed, and the default continues after
any required notice of the default and the time allowed to cure, Lender may--

     a.   declare the unpaid principal balance and earned interest on the Note
immediately due;

     b.   direct Trustee to foreclose this lien, in which case Lender or
Lender's agent will cause notice of the foreclosure sale to be given as provided
by the Texas Property Code as then in effect; and

     c.   purchase the Property at any foreclosure sale by offering the highest
bid and then have the bid credited on the Note.

                                       4
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

7.   Lender may, subject to the rights of the holder of the Prior Lien, remedy
any default without waiving it and may waive any default without waiving any
prior or subsequent default.

8.   This deed of trust, and the lien of this deed of trust, are subject and
subordinate in all respects to the Prior Lien regardless of the order in which
the Prior Lien and this deed of trust are recorded.

C.   Trustee's Rights and Duties

If directed by Lender to foreclose this lien, Trustee will--

1.   either personally or by agent give notice of the foreclosure sale as
required by the Texas Property Code as then in effect;

2.   sell and convey all or part of the Property "AS IS" to the highest bidder
for cash with a general warranty binding Grantor, subject to the Prior Lien and
to the Other Exceptions to Conveyance and Warranty and without representation or
warranty, express or implied, by Trustee;

3.   from the proceeds of the sale, pay, in this order--

     a.   expenses of foreclosure, including a reasonable commission to Trustee;

     b.   to Lender, the full amount of principal, interest, attorney's fees,
          and other charges due and unpaid;

     c.   any amounts required by law to be paid before payment to Grantor; and

     d.   to Grantor, any balance; and

4.   be indemnified by Lender against all costs, expenses, and liabilities
incurred by Trustee for acting in the execution or enforcement of the trust
created by this deed of trust, which includes all court and other costs,
including attorney's fees, incurred by Trustee in defense of any action or
proceeding taken against Trustee in that capacity.

D.   General Provisions

1.   If any of the Property is sold under this deed of trust, Grantor must
immediately surrender possession, subject to the leases affecting the Property
then in existence, to the purchaser. If Grantor fails to do so, Grantor will
become a tenant at sufferance of the purchaser, subject to an action for
forcible detainer.

2.   Recitals in any trustee's deed conveying the Property will be presumed to
be true.

                                       5
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

3.   Proceeding under this deed of trust, filing suit for foreclosure, or
pursuing any other remedy will not constitute an election of remedies.

4.   This lien will remain superior to liens later created even if the time of
payment of all or part of the Note is extended or part of the Property is
released.

5.   If any portion of the Note cannot be lawfully secured by this deed of
trust, payments will be applied first to discharge that portion.

6.   Subject to the rights of the holder of the Prior Lien, Grantor assigns to
Lender all amounts payable to or received by Borrower from condemnation of all
or part of the Property, from private sale in lieu of condemnation, and from
damages caused by public works or construction on or near the Property. After
deducting any expenses incurred, including attorney's fees and court and other
costs, but subject to the rights of the holder of the Prior Lien, Lender will
either release any remaining amounts to Grantor or apply such amounts to reduce
the Note. Lender will not be liable for failure to collect or to exercise
diligence in collecting any such amounts. Grantor will immediately give Lender
notice of any actual or threatened proceedings for condemnation of all or part
of the Property.

7.   Subject to the rights of the holder of the Prior Lien, Grantor assigns to
Lender absolutely, not only as collateral, all present and future rent and other
income and receipts from the Property. Grantor warrants the validity and
enforceability of the assignment.  Subject to the rights of the holder of the
Prior Lien, Grantor may as Lender's licensee collect rent and other income and
receipts as long as Grantor is not in default under the Note or this deed of
trust. Subject to the rights of the holder of the Prior Lien, Grantor will apply
all rent and other income and receipts to payment of the Note and performance of
this deed of trust, but if the rent and other income and receipts exceed the
amount due under the Note and deed of trust, Grantor may retain the excess. If
Grantor defaults in payment of the Note or performance of this deed of trust,
Lender may terminate Grantor's license to collect rent and other income and,
subject to the rights of the holder of the Prior Lien, then as Grantor's agent
may rent the Property and collect all rent and other income and receipts. Lender
neither has nor assumes any obligations as lessor or landlord with respect to
any occupant of the Property. Subject to the rights of the holder of the Prior
Lien, Lender may exercise Lender's rights and remedies under this paragraph
without taking possession of the Property. Lender will apply all rent and other
income and receipts collected under this paragraph first to expenses incurred in
exercising Lender's rights and remedies and then to Grantor's obligations under
the Note and this deed of trust in the order determined by Lender. Lender is not
required to act under this paragraph, and acting under this paragraph does not
waive any of Lender's other rights or remedies. If Grantor becomes a voluntary
or involuntary debtor in bankruptcy, Lender's filing a proof of claim in
bankruptcy will be deemed, subject to the rights of the holder of the Prior
Lien, equivalent to the appointment of a receiver under Texas law.

8.   Interest on the debt secured by this deed of trust will not exceed the
maximum amount of nonusurious interest that may be contracted for, taken,
reserved, charged, or received under law. Any interest in excess of that maximum
amount will be credited on the principal of the debt or, if

                                       6
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

that has been paid, refunded. On any acceleration or required or permitted
prepayment, any such excess will be canceled automatically as of the
acceleration or prepayment or, if already paid, credited on the principal of the
debt or, if the principal of the debt has been paid, refunded. This provision
overrides any conflicting provisions in this and all other instruments
concerning the debt.

9.   In no event may this deed of trust secure payment of any debt subject to
chapters 342, 343, 345, or 346 of the Texas Finance Code or create a lien
otherwise prohibited by law.

10.  When the context requires, singular nouns and pronouns include the plural.

11.  The term Note includes all extensions and renewals of the Note and all
amounts secured by this deed of trust.

12.  This deed of trust binds, benefits, and may be enforced by the successors
in interest of all parties.

13.  If Grantor and Borrower are not the same person, the term Grantor includes
Borrower.

14.  Grantor and each surety, endorser, and guarantor of the Note waive all
demand for payment, presentation for payment, notice of intention to accelerate
maturity, notice of acceleration of maturity, protest, and notice of protest, to
the extent permitted by law.

15.  Grantor agrees to pay reasonable attorney's fees, trustee's fees, and court
and other costs of enforcing Lender's rights under this deed of trust if this
deed of trust is placed in the hands of an attorney for enforcement.

16.  If any provision of this deed of trust is determined to be invalid or
unenforceable, the validity or enforceability of any other provision will not be
affected.

17.  Grantor represents that this deed of trust and the Note are given for the
following purposes: as partial purchase money financing from Lender, as seller,
to Grantor, as purchaser, for the purchase of the Property.

                           [Signature Page Follows]

                                       7
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

          IN WITNESS WHEREOF, the undersigned Grantor has executed this deed of
trust as of the date first set forth above.

GRANTOR:

WELLS OPERATING PARTNERSHIP, L.P., a Delaware limited partnership

By:  WELLS REAL ESTATE INVESTMENT TRUST, Inc.,
     a Maryland corporation, its general partner

     By: /s/ Douglas P. Williams
         ----------------------------------------------
     Printed Name: Douglas P. Williams
     Title: Executive Vice President

STATE OF GEORGIA    )
                    )        s.s.:
COUNTY OF GWINNETT  )

          On the 19/th/ day of December, 2000, before me personally came Douglas
P. Williams, who, being personally known to me or satisfactorily proved to me to
be such person, and being duly sworn by me, did depose and say that (s)he is the
Executive VP of the Wells Real Estate Investment Trust, Inc., a Maryland
corporation, which is a general partner of Wells Operating Partnership, L.P., a
Delaware limited partnership, the partnership which executed the foregoing
instrument; and that (s)he executed the foregoing instrument on behalf of such
corporation, in its capacity of general partner of such limited partnership, as
the act and deed of such limited partnership; and that (s)he was duly authorized
to execute the foregoing instrument as set forth above.

                                        /s/ W. L. O'Callaghan
                                        -------------------------------------
                                        Name:
                                        Notary Public of the State of Georgia

                                        My commission expires _______________
                                                                         [STAMP]

                                       8
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

                                   EXHIBIT A
                                   ---------

                           LEGAL DESCRIPTION OF LAND

Reserve "I", in Block 6 of Partial Replat of Enclave, a subdivision in Harris
County, Texas, according to the map or plat thereof recorded in Volume 328 Page
13 of the Map Records of Harris County, Texas.

                                       9
<PAGE>

                                   EXHIBIT "B"

1.   Restrictions recorded in Volume 328 Page 13 of the Map Records of Harris
     County, Texas.  Restrictions filed for record under Clerk's File Nos. J
     469311, M 463582 and P 007809, P684693, R369841 and T092402 of the Official
     Public Records of Real Property of Harris County, Texas.

2.   An easement 10 feet wide along the most northerly west property line and
     the most southerly west property line, and an aerial easement 5 feet wide
     from a plane 20 feet above the ground upward located adjacent thereto, for
     the use of public utilities, as reflected by the plat recorded in Volume
     328 Page 13 of the Map Records of Harris County, Texas.

3.   An easement 10 feet wide along the most westerly south property line and an
     aerial easement 5 feet wide from a plane 20 feet above the ground upward
     located adjacent thereto, for the use of public utilities, as reflected by
     the plat recorded in Volume 328 Page 13 of the Map Records of Harris
     County, Texas.

4.   Water line easement 10 feet wide at its widest point along a portion of the
     northerly property line beginning at its northwest corner and extending
     east approximately 150 feet, as shown on the plat recorded in Volume 328
     Page 13 of the Map Records of Harris County, Texas.

5.   An easement 5 feet wide along the east property line for sanitary sewer
     purposes as shown on the plat recorded in Volume 328 Page 13 of the Map
     Records of Harris County, Texas.  Consent to encroachment of driveway and
     sidewalk into above easement as set out in instrument recorded under Harris
     County Clerk's File No. PO11968.

6.   An additional unobstructed aerial easement 11 feet 6 inches wide, beginning
     at a plane of 16 feet above the ground and extending upward, located
     adjacent to and adjoining the 10 foot wide dedicated utility easement
     located along the west property lines and the most westerly south property
     line, granted to Houston Lighting & Power Company by instrument dated
     November 14, 1984, filed for record under Clerk's File No. J 853626 of the
     Official Public Records of Real Property of Harris County, Texas.

7.   Location of guy wire outside utility easement as shown on survey prepared
     by Sander Engineering Corporation dated December 1992 and last revised
     December 17, 1992.  This guy wire is also set our in deed filed for record
     under Clerk's File No. M 677551 of the Official Public Records of Real
     Property of Harris County, Texas.

8.   Building set back line of 25 feet along the most southerly property line,
     as set out on plat of Enclave recorded in Volume 328 Page 13 of the Map
     Records of Harris County, Texas.
<PAGE>

9.   Building set back line of 10 feet along north and east property lines as
     set out on plat of Enclave recorded in Volume 328 Page 13 of the Map
     Records of Harris County, Texas.

10.  Annual Maintenance Charge and Special Assessments payable to Enclave
     Environmental Association, Inc. as set forth in instrument filed for record
     under Clerk's File No. J 469311 of the Official Public Records of Real
     Property of Harris County, Texas, and additional secured by a vendor's lien
     as set forth therein.

11.  A Houston Lighting and Power Company easement 10 feet in width, together
     with an unobstructed aerial easement located on both sides of and adjacent
     to the aforesaid easement, being 10 feet wide from a plane 16 feet above
     the ground upward and being more particularly set out and described in
     instrument recorded under Harris County Clerk's File No. P467137.

12.  A Houston Lighting and Power Company easement, being 9 feet by 12 feet and
     15 feet by 20 feet as set out in instrument recorded under Harris County
     clerk's file No. P467137.

13.  Water meter easement 10 feet by 20 feet located in the most southerly
     southwest portion of subject property as set out in instrument recorded
     under Harris County Clerk's File No. P735630.

14.  Visible and apparent easements and rights-of-way which may be evidenced by
     a current survey or disclosed by physical inspection of the property.
<PAGE>

Texas Real Estate Forms 15-1                                     Deed of Trust

                                   EXHIBIT B
                                   ---------

                  OTHER EXCEPTIONS TO CONVEYANCE AND WARRANTY

1. Lease dated July 20, 1998, by and between Enclave Parkway Realty, Inc., as
   landlord, and Sysco Corp.

2. Lease dated on or about date hereof by and between Grantor, as landlord,
   and Stone & Webster, Inc., as tenant.<PAGE>

                                                                   EXHIBIT 10.72
                  LEASE AGREEMENT WITH STONE & WEBSTER, INC.
<PAGE>

                             1430 ENCLAVE PARKWAY
                                HOUSTON, TEXAS

                             OFFICE BUILDING LEASE

                                    BETWEEN

                       WELLS OPERATING PARTNERSHIP, L.P.

                        a Delaware limited partnership

                                  AS LANDLORD

                                      AND

                             STONE & WEBSTER, INC.

                            a Louisiana corporation

                                   AS TENANT
<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
PART ONE
<S>                                                                                <C>
     BASIC LEASE PROVISIONS......................................................  Part One-Page 7

                  1.       Tenant................................................  Part One-Page 7
                           ------
                  2.       Premises..............................................  Part One-Page 7
                           --------
                  3.       Term:.................................................  Part One-Page 7
                           ----
                  4.       Base Rent (Part Two, Section 3.1).....................  Part One-Page 7
                           ---------
                  5.       Expense Stop..........................................  Part One-Page 7
                           ------------
                  6.       Security Deposit......................................  Part One-Page 7
                           ----------------
                  7.       Premises Use..........................................  Part One-Page 7
                           ------------
                  8.       Tenant's Insurance....................................  Part One-Page 7
                           ------------------
                  9.       Addresses For Notices and Payment of
                           ------------------------------------
                           Rent and Other Charges................................  Part One-Page 8
                           -----------------------
                  10.      Brokers (Part Two, Article 17)........................  Part One-Page 8
                           -------
                  11.      Exhibits and Riders...................................  Part One-Page 8
                           -------------------
                  12.      Incorporation of Other Provisions.....................  Part One-Page 8
                           ---------------------------------

GENERAL LEASE PROVISIONS.........................................................  Part Two-Page 1

         1.       PREMISES, COMMON AREAS, SERVICE AREAS..........................  Part Two-Page 1
                  -------------------------------------
                  1.1      Building..............................................  Part Two-Page 1
                           --------
                  1.2      Ceilings, Walls, Floors...............................  Part Two-Page 1
                           -----------------------
                  1.3      Condition of Premises.................................  Part Two-Page 1
                           ---------------------
                  1.4      Common and Service Areas..............................  Part Two-Page 1
                           ------------------------
                           (a)      Common Areas.................................  Part Two-Page 1
                                    ------------
                           (b)      Service Areas................................  Part Two-Page 1
                                    -------------
         2.       TERM; RENEWAL..................................................  Part Two-Page 1
                  -------------
                  2.1      Term..................................................  Part Two-Page 1
                           ----
                  2.2      Renewal...............................................  Part Two-Page 2
                           -------
                  2.3      Holding Over..........................................  Part Two-Page 3
                           ------------
         3.       MONETARY PROVISIONS............................................  Part Two-Page 3
                  -------------------
                  3.1      Base  Rent............................................  Part Two-Page 3
                           ----------
                  3.2      Tenant's Share of Certain Costs.......................  Part Two-Page 3
                           -------------------------------
                           (a)      Operating Costs..............................  Part Two-Page 3
                                    ---------------
                           (b)      Pro Rata Share Computation...................  Part Two-Page 3
                                    --------------------------
                           (c)      Estimated Costs..............................  Part Two-Page 4
                                    ---------------
                           (d)      Estimate Revisions...........................  Part Two-Page 4
                                    ------------------
                           (e)      Annual Adjustments...........................  Part Two-Page 4
                                    ------------------
</TABLE>
                                       i
<PAGE>

<TABLE>
<S>                                                                                            <C>
                           (f)      Final Partial Year.......................................  Part Two-Page 5
                                    ------------------
                           (g)      Adjustment for Occupancy.................................  Part Two-Page 5
                                    ------------------------
                  3.3      Personal Property Taxes...........................................  Part Two-Page 5
                           -----------------------
                  3.4      Late Payments.....................................................  Part Two-Page 6
                           -------------
                  3.5      Interest..........................................................  Part Two-Page 6
                           --------
                  3.6      Administrative Reimbursement......................................  Part Two-Page 6
                           ----------------------------
                  3.7      Additional Rent...................................................  Part Two-Page 6
                           ---------------
         4.       SYSCO CORPORATION LEASE....................................................  Part Two-Page 6
                  -----------------------
         5.       SERVICES AND UTILITIES.....................................................  Part Two-Page 6
                  ----------------------
                  5.1      Services by Landlord..............................................  Part Two-Page 6
                           --------------------
                  5.2      Tenant's Obligations..............................................  Part Two-Page 7
                           --------------------
                  5.3      Tenant's Additional Service Requirements..........................  Part Two-Page 7
                           ----------------------------------------
                           (a)  Additional Services Requiring
                                -----------------------------
                                    Landlord Consent.........................................  Part Two-Page 7
                                    ----------------
                           (b)      Providing Additional Services............................  Part Two-Page 7
                                    -----------------------------
                                    (i)     Removal by Tenant. ..............................  Part Two-Page 7
                                            -----------------
                                    (ii)    Separate Metering................................  Part Two-Page 8
                                            -----------------
                                    (iii)   Additional HVAC..................................  Part Two-Page 8
                                            ---------------
                                    (iv)    Replacement Bulbs................................  Part Two-Page 8
                                            -----------------
                                    (v)     Additional Janitorial Services...................  Part Two-Page 8
                                            ------------------------------
                                    (vi)    Substitution of Cleaning Contractors.............  Part Two-Page 8
                                            ------------------------------------
                           (c)      After Hours Heat or Air Conditioning.....................  Part Two-Page 8
                                    ------------------------------------
                           (d)      Payment..................................................  Part Two-Page 9
                                    -------
                  5.4      Interruption of Utility Service...................................  Part Two-Page 9
                           -------------------------------
         6.       OCCUPANCY AND CONTROL......................................................  Part Two-Page 9
                  ---------------------
                  6.1      Use...............................................................  Part Two-Page 9
                           ---
                  6.2      Access to the Building and Premises;
                           ------------------------------------
                           Telephone System..................................................  Part Two-Page 9
                           ----------------
                  6.3      Rules and Regulations.............................................  Part Two-Page 10
                           ---------------------
                  6.4      Additional Covenants of Tenant....................................  Part Two-Page 10
                           ------------------------------
                           (a)      Laws, Statutes...........................................  Part Two-Page 10
                                    --------------
                           (b)      Nuisance.................................................  Part Two-Page 11
                                    --------
                           (c)      Building Reputation......................................  Part Two-Page 11
                                    -------------------
                           (d)      Recording................................................  Part Two-Page 11
                                    ---------
                  6.5      Access by Landlord................................................  Part Two-Page 11
                           ------------------
                  6.6      Control of Project................................................  Part Two-Page 11
                           ------------------
                  6.7      Minimization of Disruption........................................  Part Two-Page 11
                           --------------------------
         7.       REPAIRS, MAINTENANCE AND ALTERATIONS.......................................  Part Two-Page 12
                  ------------------------------------
                  7.1      Landlord's Repair Obligations.....................................  Part Two-Page 12
                           -----------------------------
                  7.2      Tenant's Repair Obligations.......................................  Part Two-Page 12
                           ---------------------------
</TABLE>

                                      ii
<PAGE>

<TABLE>
<S>                                                                                  <C>
                  7.3      Rights of Landlord.....................................   Part Two-Page 13
                           ------------------
                  7.4      Surrender..............................................   Part Two-Page 13
                           ---------
                  7.5      Alterations by Tenant..................................   Part Two-Page 13
                           ---------------------
                           (a)      Approval Required.............................   Part Two-Page 13
                                    -----------------
                           (b)      Complex Alterations...........................   Part Two-Page 14
                                    -------------------
                           (c)      Standard of Work..............................   Part Two-Page 14
                                    ----------------
                           (d)      Ownership of Alterations......................   Part Two-Page 14
                                    ------------------------
                  7.6      Liens..................................................   Part Two-Page 14
                           -----
         8.       INSURANCE.......................................................   Part Two-Page 14
                  ---------
                  8.1      Insurance Required of Tenant...........................   Part Two-Page 14
                           ----------------------------
                           (a)      Commercial General Liability Insurance........   Part Two-Page 14
                                    --------------------------------------
                           (b)      Workers' Compensation and Employer
                                    ----------------------------------
                                    Liability Coverage............................   Part Two-Page 15
                                    -------------------
                           (c)      Property Insurance............................   Part Two-Page 15
                                    ------------------
                           (d)      Business Income and Extra
                                    -------------------------
                                    Expense Coverage..............................   Part Two-Page 15
                                    ----------------
                  8.2      Landlord's Insurance...................................   Part Two-Page 15
                           --------------------
                  8.3      Form of Policies and Additional Requirements...........   Part Two-Page 16
                           --------------------------------------------
                  8.4      Waiver of Subrogation..................................   Part Two-Page 16
                           ---------------------
                  8.5      Increase of Premiums...................................   Part Two-Page 16
                           --------------------
         9.       DAMAGE OR DESTRUCTION...........................................   Part Two-Page 17
                  ---------------------
                  9.1      Repair by Landlord.....................................   Part Two-Page 17
                           ------------------
                  9.2      Landlord's Rights Upon The Occurrence
                           -------------------------------------
                           of Certain Casualties..................................   Part Two-Page 17
                           ----------------------
                  9.3      Tenant's Rights Upon The Occurrence
                           -----------------------------------
                           of Certain Casualties..................................   Part Two-Page 18
                           ---------------------
                  9.4      Repairs by Tenant......................................   Part Two-Page 18
                           -----------------
                  9.5      Determination or Period Required for Rebuilding........   Part Two-Page 18
                           -----------------------------------------------
         10.      EMINENT DOMAIN..................................................   Part Two-Page 19
                  --------------
                  10.1     Total Taking...........................................   Part Two-Page 19
                           ------------
                  10.2     Partial Taking.........................................   Part Two-Page 19
                           --------------
                  10.3     Award..................................................   Part Two-Page 19
                           -----
         11.      ASSIGNMENT AND SUBLETTING.......................................   Part Two-Page 20
                  -------------------------
                  11.1     Consent................................................   Part Two-Page 20
                           -------
                  11.2     Definitions of Assignment and Affiliate................   Part Two-Page 20
                           ---------------------------------------
         12.      DEFAULT; REMEDIES...............................................   Part Two-Page 21
                  -----------------
                  12.1     Defaults by Tenant.....................................   Part Two-Page 21
                           ------------------
                  12.2     Remedies...............................................   Part Two-Page 21
                           --------
                           (a)      Termination of Lease..........................   Part Two-Page 22
                                    --------------------
                           (b)      Continuation of Lease.........................   Part Two-Page 22
                                    ---------------------
</TABLE>

                                      iii
<PAGE>

<TABLE>
<S>                                                                                  <C>
                           (c)      Performance for Tenant........................   Part Two-Page 22
                                    ----------------------
                           (d)      Changing Locks................................   Part Two-Page 22
                                    --------------
                  12.3     Remedies Cumulative....................................   Part Two-Page 22
                           -------------------
                  12.4     Default by Landlord....................................   Part Two-Page 23
                           -------------------
                  12.5     Attorneys' Fees........................................   Part Two-Page 23
                           ---------------
                  12.6     Waiver.................................................   Part Two-Page 23
                           ------
                  12.7     Force Majeure..........................................   Part Two-Page 24
                           -------------
         13.      ESTOPPEL CERTIFICATES...........................................   Part Two-Page 24
                  ---------------------
                  13.1     Acknowledgment of Commencement Date....................   Part Two-Page 24
                           -----------------------------------
                  13.2     Certificates...........................................   Part Two-Page 24
                           ------------
                  13.3     Financial Statements...................................   Part Two-Page 24
                           --------------------
         14.      SUBORDINATION AND ATTORNMENT....................................   Part Two-Page 24
                  ----------------------------
                  14.1 Lease Subordinate..........................................   Part Two-Page 24
                       -----------------
                  14.2 Subordination..............................................   Part Two-Page 25
                       -------------
         15.      LANDLORD'S INTEREST.............................................   Part Two-Page 25
                  -------------------
                  15.1     Liability of Landlord..................................   Part Two-Page 25
                           ---------------------
                  15.2     Sale of Project........................................   Part Two-Page 25
                           ---------------
         16.      NOTICES.........................................................   Part Two-Page 25
                  -------
         17.      BROKERS.........................................................   Part Two-Page 25
                  -------
         18.      INDEMNITIES AND WAIVERS.........................................   Part Two-Page 26
                  -----------------------
                  18.1     Indemnities by Tenant..................................   Part Two-Page 26
                           ---------------------
                  18.2     Indemnities by Landlord................................   Part Two-Page 26
                           -----------------------
                  18.3     Waivers by Tenant......................................   Part Two-Page 26
                           -----------------
                  18.4     Waivers by Landlord....................................   Part Two-Page 26
                           -------------------
                  18.5     Definitions............................................   Part Two-Page 27
                           -----------
                  18.6     Scope of Waivers.......................................   Part Two-Page 27
                           ----------------
                  18.7     Obligations Independent of Insurance...................   Part Two-Page 27
                           ------------------------------------
                  18.8     Survival...............................................   Part Two-Page 28
                           --------
                  18.9     Duty to Defend.........................................   Part Two-Page 28
                           --------------
         19.      PARKING.........................................................   Part Two-Page 28
                  -------
                  19.1     Garage.................................................   Part Two-Page 28
                           ------
         20.      HAZARDOUS SUBSTANCES;
                  ----------------------
                  REPRESENTATIONS.................................................   Part Two-Page 28
                  ---------------
                  20.1     Tenant's Operations....................................   Part Two-Page 28
                           -------------------
         21.      INTERPRETATIVE..................................................   Part Two-Page 29
                  --------------
                  21.1     Captions...............................................   Part Two-Page 29
                           --------
                  21.2     Section Numbers........................................   Part Two-Page 29
                           ---------------
                  21.3     Attachments............................................   Part Two-Page 29
                           -----------
                  21.4     Number, Gender, Defined Terms..........................   Part Two-Page 29
                           -----------------------------
                  21.5     Entire Agreement.......................................   Part Two-Page 29
                           ----------------
</TABLE>

                                      iv
<PAGE>

<TABLE>
<S>                                                                                  <C>
                  21.6    Amendment................................................  Part Two-Page 29
                          ---------
                  21.7    Severability.............................................  Part Two-Page 29
                          ------------
                  21.8    Time of Essence..........................................  Part Two-Page 29
                          ---------------
                  21.9    Best Efforts.............................................  Part Two-Page 29
                          ------------
                  21.10   Binding Effect...........................................  Part Two-Page 30
                          --------------
                  21.11   Subtenancies.............................................  Part Two-Page 30
                          ------------
                  21.12   No Reservation...........................................  Part Two-Page 30
                          --------------
                  21.13   Consents.................................................  Part Two-Page 30
                          --------
                  21.14   Choice of Law............................................  Part Two-Page 30
                          -------------
                  21.15   Non-Merger...............................................  Part Two-Page 30
                          ----------
                  21.16   Representations of Landlord..............................  Part Two-Page 30
                          ---------------------------
                  21.17   Jointly Prepared Document................................  Part Two-Page 30
                          -------------------------
                  21.18   Waiver of Trial by Jury..................................  Part Two-Page 30
                          -----------------------
                  21.19   Independent Covenants....................................  Part Two-Page 31
                          ---------------------
                  21.20   Execution on Behalf of Tenant............................  Part Two-Page 31
                          -----------------------------
                  21.21   Execution on Behalf of Landlord..........................  Part Two-Page 31
                          -------------------------------
                  21.22   Quiet Enjoyment..........................................  Part Two-Page 31
                          ---------------
                  21.23   Conflict with Rules and Regulations.....................   Part Two-Page 31
                          -----------------------------------

                  EXHIBIT A........................................................  Exhibit A - page 1
                  EXHIBIT B........................................................  Exhibit B, page 1
                  EXHIBIT C........................................................  Exhibit C, page 1
                  EXHIBIT D........................................................  Exhibit D, Page 1
                  EXHIBIT E........................................................  Exhibit E, Page 1
                  EXHIBIT F........................................................  Exhibit F, Page 1
                  EXHIBIT G........................................................  Exhibit G, Page 2
</TABLE>

                                       v
<PAGE>

                             OFFICE BUILDING LEASE
                             ---------------------

     In consideration of the mutual covenants and upon the terms and conditions
set forth in Part One "Basic Lease Provisions", Part Two "General Lease
Provisions", and other attachments and exhibits numerated in the Table of
Contents to this Office Building Lease ("Lease"), Wells Operating Partnership,
L.P., a Delaware limited partnership ("Landlord"), hereby leases to the Tenant
named below and Tenant hereby leases from Landlord, certain premises described
below.

                                   PART ONE

                            BASIC LEASE PROVISIONS

     1.   Tenant: Stone & Webster, Inc.
          ------

     2.   Premises: The premises outlined and crosshatched on Exhibit B hereof
          --------                                            ---------
          and agreed by Landlord and Tenant to contain 206,048 square feet of
          Rentable Area on the first through fourth floors of the Building.
          (Part Two, Article 1)

     3.   Term: Beginning on ______________, 2000 (the "Commencement Date") and
          ----
          ending on  _____________,  2010 (the "Expiration Date"). (Part Two,
          Article 2)

     4.   Base Rent (Part Two, Section 3.1):  Base Rent shall be as follows:
          ---------

          Years            Annual Rent            Monthly Installment
          -----            -----------            -------------------
          1-5               $ 4,533,056                   $377,754.67
          6-10              $ 5,213,014                   $434,417.83

     5.   Expense Stop: $7.50 per square foot {of Rentable Area} [Part Two,
          ------------
          Section 3.2(b)(i)]

     6.   Security Deposit: None (Part Two, Section 3.5)
          ----------------

     7.   Premises Use: Office space. (Part Two, Article 6)
          ------------

     8.   Tenant's Insurance (Part Two, Article 8):
          ------------------

          Commercial General Liability:                   $ 5,000,000

                                Part One-Page 7
<PAGE>

          Workers' Compensation:                          Statutory Limit
          Employers' Liability:                           $ 1,000,000
          All Risk Property:                              Full Replacement Value
          Business Interruption/Excess Expense:           12 months' coverage

     9.   Addresses For Notices and Payment of Rent and Other Charges (Part Two,
          -----------------------------------------------------------
          Article 16):

     TO TENANT:                               TO LANDLORD:

     Stone & Webster, Inc.                    Wells Operating Partnership, L.P.
     8545 United Plaza Blvd.                  10000 N. Central Expressway
     Baton Rouge, Louisiana 70809             Suite 1150
     Attn: Walter R. Rhodes,                  Dallas, Texas 75231
           Executive Vice President

     with a copy to:

     The Shaw Group, Inc.
     8545 United Plaza Blvd.
     Baton Rouge, Louisiana 70809
     Attn: General Counsel

     10.  Brokers (Part Two, Article 17): C B Richard Ellis and Means Knaus.
          -------

     11.  Exhibits and Riders: The following numbered Riders are attached to
          -------------------
          this Lease and made of a part of this Lease for all purposes:

          Exhibit A: Legal Description of Project
          Exhibit B: Floor Plans
          Exhibit C: Operating Costs
          Exhibit D: Rules and Regulations
          Exhibit E: Subordination, Non-Disturbance and Attornment Agreement
          Exhibit F: Guaranty
          Exhibit G: Site Plan, Showing Excess Land

     12.  Incorporation of Other Provisions: All of the provisions, covenants
          ---------------------------------
          and conditions set forth in Part Two and all other exhibits and riders
          described in the attached Table of Contents and the preceding
          paragraph, are by this reference incorporated into the Basic Lease
          Provisions as fully as if the same

                                Part One-Page 8
<PAGE>

          were set forth at length in the Basic Lease Provisions. Each reference
          in Part Two and exhibits and riders to any provision in the Basic
          Lease Provisions will be construed to incorporate all of the terms
          provided under the referenced provision in the Basic Lease Provisions.
          In the event of any conflict between a provision in the Basic Lease
          Provisions, on the one hand, and a provision in Part Two or exhibits
          or riders, on the other hand, the latter will control.

     This Lease has been executed by Landlord and Tenant as of the _____ day of
_________________, 2000.

TENANT:                                      LANDLORD:

Stone & Webster, Inc.                        Wells Operating Partnership, L.P.

By: /s/ Walter R. Rhodes                     By:_____________________________
   ------------------------------
Name: Walter R. Rhodes                       Name:___________________________
     ----------------------------
Title: Executive Vice President              Title:__________________________
      ---------------------------

                                Part One-Page 9
<PAGE>

     This Lease has been executed by Landlord and Tenant as of the 21st day of
December, 2000.

TENANT:                                 LANDLORD:

Stone & Webster, Inc.                   Wells Operating Partnership, L.P.

By:______________________________       By: /s/ Douglas P. Williams
                                           -----------------------------
Name:____________________________       Name: Douglas P. Williams
                                             ---------------------------
Title:___________________________       Title: Executive Vice President
                                              --------------------------

                                Part One-Page 10
<PAGE>

                                   PART TWO

                           GENERAL LEASE PROVISIONS

1.   PREMISES, COMMON AREAS, SERVICE AREAS
     -------------------------------------

     1.1  Building.  The term "Building" in this Lease will refer to the office
          --------
building situated on a tract of land ("Land") in Houston, Texas, described in
Exhibit A of this Lease, and having a postal address of 1430 Enclave Parkway,
---------
Houston, Texas.  The Land, Building, and any other improvements situated on the
Land are sometimes referred to collectively as the "Project".

     1.2  Ceilings, Walls, Floors.  Tenant acknowledges that pipes, ducts,
          -----------------------
conduits, wires and equipment serving other parts of the Building may be located
above acoustical ceiling surfaces, below floor surfaces or within walls in the
Premises.

     1.3  Condition of Premises.  Tenant acknowledges that the Premises and the
          ---------------------
Project are in satisfactory order and condition.  Tenant further agrees to
accept the Premises and the Project "as is."

     1.4  Common and Service Areas. Tenant is hereby granted a nonexclusive
          ------------------------
right to use the Common Areas during the term of this Lease for their intended
purposes, in common with others, subject to the terms and conditions of this
Lease, including, without limitation, the provisions of Section 19 pertaining to
use of the parking areas and the Rules and Regulations.

          (a)  Common Areas.  "Common Areas" will mean all areas, spaces,
               ------------
facilities, and equipment in the Project made available by Landlord for the
common and joint use of Landlord, Tenant and, subject to Section 19, others,
including, but not limited to, sidewalks, parking areas, driveways, landscaped
areas, loading areas, public corridors, public restrooms, Building lobbies,
stairs and elevators, drinking fountains and such other areas and facilities, if
any, as are designated by Landlord from time to time as Common Areas. Tenant
acknowledges that the Project has unimproved land (the "Excess Land") that is
not necessary for Tenant's occupancy. The Excess Land is identified on the site
plan attached hereto as Exhibit G. Landlord shall have the right to sell the
                        ---------
Excess Land or use the Excess Land for other purposes and the Excess Land shall
not be deemed to be part of Common Areas.

          (b)  Service Areas.  "Service Areas" will refer to areas, spaces,
               -------------
facilities and equipment serving the Project but to which Tenant and other
occupants of the Building will not have access, including, but not limited to,
mechanical, electrical and similar rooms, and air and water refrigeration
equipment.

2.   TERM; RENEWAL
     -------------

     2.1  Term.  The Term of this Lease will commence on the Commencement Date
          ----
set forth in the Basic Lease Provisions and will terminate on the Expiration
Date set forth in the Basic

                                Part Two-Page 1
<PAGE>

Lease Provisions, unless sooner terminated in accordance with the provisions of
this Lease.

     2.2  Renewal.
          -------

          (a)  Provided this Lease shall not have been terminated pursuant to
the provisions hereof, this Lease and the term thereof may be extended for up to
two (2) renewal terms of five (5) years each upon Tenant giving notice, in
accordance with the provisions of Paragraph 16, to Landlord of such renewal at
least twelve (12) months prior to the expiration of the then current Term, time
being deemed to be of the essence with respect to Tenant's exercise of such
renewal option. Any such extension or renewal of the Term shall be subject to
all of the provisions of this Lease, and all such provisions shall continue in
full force and effect except that the Base Rent for each renewal term shall be
determined in accordance with the provision hereof.

          (b)  The Base Rent for each renewal term shall be upon an annual
rental rate equal to the Fair Market Rental Value of the Premises on the first
day of the renewal term at issue, as determined by agreement between Landlord
and Tenant or by the Appraisal Procedure, except, however, that such Base Rent
shall not in any event be less than the Base Rent in effect on the day before
the commencement of the renewal term at issue.

          (c)  The term "Fair Market Rental Value" shall mean the fair market
rent that would be obtained in an arm's-length transaction between an informed
and willing tenant and an informed and willing landlord, in either case under no
compulsion to lease, and neither of which is related to Landlord, or Tenant, for
the lease of the Premises. Such fair market rental value shall be calculated as
the value for the use of the Premises, assuming, in the determination of such
fair market rental value, that the Premises is in the condition and repair
required to be maintained by Tenant by the terms of this Lease.

          (d)  "Appraisal Procedure" shall mean the following procedure for
determining the Fair Market Rental Value of the Premises after Landlord and
Tenant have failed to reach agreement within sixty (60) days after the exercise
by Tenant of its renewal option. Tenant and Landlord shall, within thirty (30)
days after the end of such sixty (60) day period, each select an appraiser which
is a member in good standing of the American Institute of Real Estate Appraisers
with at least ten (10) years experience (such appraisers are hereinafter
referred to as an "Approved Appraiser"). If either party shall fail to choose an
Approved Appraiser within 30 days after notice from the other party of the
selection of its Approved Appraiser, then the appraisal by such appointed
Approved Appraiser shall be binding on Tenant and Landlord. If the two Approved
Appraisers cannot agree within 30 days after both shall have been appointed,
then a third Approved Appraiser shall be selected by the two Approved Appraisers
or, failing agreement as to such third Approved Appraiser within 30 days after
both shall have been appointed, by the American Arbitration Association. The
decisions of the three Approved Appraisers shall be given within 30 days of the
appointment of the third Approved Appraiser and the decision of the Approved
Appraiser most different from the average of the other two shall be discarded
and such average shall be binding on Landlord and Tenant; provided that if the
                                                          --------
highest appraisal and the lowest appraisal are equidistant in value from the
third appraisal, the third appraisal shall be binding on Landlord and Tenant.
All appraisals

                                Part Two-Page 2
<PAGE>

hereunder shall be certified to Landlord and Tenant.  The fees and expenses of
the Appraisal Procedure shall be paid by Tenant.

     2.3  Holding Over.  If Tenant, or any party claiming rights to the Premises
          ------------
through Tenant, retains possession of the Premises without the written consent
of Landlord after the Expiration Date or earlier termination of this Lease, such
possession will constitute a tenancy at will, subject, however, to all the terms
and provisions of this Lease, except for (i) the Term and (ii) the annual Base
Rent, which annual Base Rent will become an amount equal to one hundred twenty-
five percent (125%) of the highest amount set forth in this Lease as annual Base
Rent, plus any adjustments which have previously occurred.  No holding over by
Tenant, and no acceptance of rental payments by Landlord during a holdover
period, whether with or without the consent of Landlord, will operate to extend
this Lease.

3.   MONETARY PROVISIONS
     -------------------

     3.1  Base Rent. Tenant will pay as the monthly installment of "Base Rent"
          ----------
for each month of the Term, the sum set forth in the Basic Lease Provisions, in
advance on or before the first day of each calendar month of the Term, without
deduction, offset, prior notice, or demand, and in lawful money of the United
States. If the Commencement Date is not the first day of a calendar month,
Tenant will pay to Landlord on the Commencement Date a portion of the monthly
installment of Base Rent prorated on the basis of a thirty (30) day month.

     3.2  Tenant's Share of Certain Costs. In addition to all other sums due
          -------------------------------
under this Lease, Tenant will pay to Landlord as additional monthly rent, in the
manner and at the times set forth below, Tenant's Pro-Rata Share of Operating
Costs as calculated in accordance with Section 3.2(b) for each calendar year or
partial calendar year.

          (a)  Operating Costs. "Operating Costs" will mean all costs, charges,
               ---------------
and expenses incurred by Landlord in connection with operating, maintaining,
repairing, insuring and managing the Project, provided that such Operating Costs
are substantially consistent with Operating Costs incurred by owners of other
first-class office buildings in the Houston, Texas area. Operating Costs shall
be computed on an accrual basis and shall include, without limitation, costs,
charges and expenses incurred with respect to the items enumerated as "Operating
Cost Examples" in  Paragraph 2 of Exhibit C to this Lease. Operating Costs will
                   -----------    ---------
not include those items enumerated as "Operating Cost Exclusions" in Paragraph 1
                                                                     -----------
of Exhibit C to this Lease.  Tenant reserves the right to protest or appeal the
   ---------
appraised value of the Premises, as well as the Project and Building, and the
right to receive notices of reappraisement as set forth in Sections 41.413 and
42.015 of the Texas Tax Code.

          (b)  Pro Rata Share Computation.
               --------------------------

               (i)  From the date hereof until and including the earlier of
September 20, 2008 or the cancellation or termination of the Sysco Lease (as
defined in Paragraph 4 of Part Two of this Lease), "Tenant's Pro Rata Share of
Operating Costs" will be computed by multiplying (A) the amount, if any, by
which the Operating Costs per square foot of Rentable Area in the Building
exceed the Expense Stop, times (B)312,564, provided, however, that Tenant's Pro
Rata Share of Operating Costs shall be reduced by the amount

                                Part Two-Page 3
<PAGE>

of money Landlord actually receives under the Sysco Lease (as defined in Section
4 hereof) for such Tenant's Proportionate Share of any increases in Taxes and
Operating Costs under Section 3(c)(3) and (4) of the Sysco Lease.

               (ii) From and after the earlier of September 21, 2008 or the
cancellation or termination of the Sysco Lease, "Tenant's Pro Rata Share of
Operating Costs" will be computed by multiplying (A) the amount, if any, by
which the Operating Costs per square foot of Rentable Area in the Building
exceed the Expense Stop, times (B) the number of square feet of Rentable Area of
the Building (which, for purposes of this calculation, is stipulated to be
312,564 square feet), times (C) sixty-five and 92/100 percent (65.92%).

     (c)  Estimated Costs.  Tenant's Pro Rata Share of Operating Costs for the
          ---------------
remainder of the first calendar year (whether full or partial) and for each
subsequent calendar year of the Term will be estimated by Landlord, and notice
of such estimated amounts will be given to Tenant at least thirty (30) days
prior to the Commencement Date or the beginning of each calendar year, as the
case may be.  For the partial calendar year after the Commencement Date, Tenant
will pay to Landlord each month, at the same time as the monthly installment of
Base Rent is due, an amount equal to Tenant's estimated Pro Rata Share of
Operating Costs for the remainder of such calendar year divided by the number of
full months remaining in such year.  For each full calendar year of the Term,
Tenant will pay to Landlord each month, at the same time as the monthly
installment of Base Rent is due, an amount equal to one-twelfth (1/12) of
Tenant's estimated Pro Rata Share of Operating Costs due for such calendar year.
If the Expiration Date does not occur on December 31, for the partial calendar
year preceding the Expiration Date, Tenant will pay to Landlord, each month, at
the same time as the monthly installment of Base Rent is due, an amount equal to
the amount of Tenant's estimated Pro Rata Share of Operating Costs for such
partial calendar year divided by the number of full calendar months of such
partial calendar year.

     (d)  Estimate Revisions.  At any time and from time to time during the
          ------------------
Term, Landlord will have the right, by notice to Tenant, to change the monthly
amount then payable by Tenant for Tenant's estimated Pro Rata Share of Operating
Costs to reflect more accurately, in the reasonable judgment of Landlord, the
actual amount of such costs payable by Tenant for the then current calendar
year.  Tenant will begin paying the revised estimated amount together with the
next monthly payment of Base Rent due after receipt by Tenant of Landlord's
notice.

     (e)  Annual Adjustments.  On or before April 1 of each calendar year,
          ------------------
Landlord will prepare and deliver to Tenant a statement setting forth the
calculation of Tenant's actual Pro Rata Share of Operating Costs for the
previous calendar year.  Within thirty (30) days after receipt of such
statement, Tenant will pay to Landlord, or Landlord will credit against the next
rental or other payment or payments due from Tenant, as the case may be, the
difference between Tenant's actual Pro Rata Share of Operating Costs for the
preceding calendar year and Tenant's estimated Pro Rata Share of Operating Costs
paid by Tenant during such year. Tenant shall have the right to conduct an audit
("Tenant's Audit") of the Operating Costs in respect of a calendar year provided
that all the following conditions are met in strict accordance

                                Part Two-Page 4
<PAGE>

with their terms: (i) such audit is conducted within two (2) years after
Landlord delivers to Tenant the calculation of Tenant's actual Pro Rata Share of
Operating Costs for such calendar year (time being of the essence with respect
thereto); and (ii) such audit is conducted at hours reasonably designated by
Landlord. The results of Tenant's Audit shall be made available to Landlord. The
result of Tenant's Audit shall be binding upon the parties unless Landlord,
during the thirty (30) day period after receipt of Tenant's Audit, requests that
another audit of the relevant costs be performed. If such request is timely
made, Landlord and Tenant shall retain a mutually acceptable accounting firm to
conduct such audit (the "Mutual Audit"), the results of which shall be binding
upon the parties. The cost of the Mutual Audit shall be borne equally by
Landlord and Tenant. Tenant shall pay the cost of Tenant's Audit; provided,
however, that if Tenant's Audit (or, in the alternative, the Mutual Audit if one
is conducted) determines that Landlord's calculation of Operating Expenses was
overstated by more than five percent (5%), then Landlord shall pay the entire
cost of the Mutual Audit and reimburse Tenant for the cost of Tenant's Audit. If
Tenant's Audit (or, in the alternative, the Mutual Audit if one is conducted)
determines that Landlord has charged, and Tenant has paid, Operating Costs in
excess of such costs required to be paid by Tenant under the terms of this
Lease, Landlord shall, at Landlord's election (notice of which election shall be
sent to Tenant within twenty (20) days after the amount of any such excess has
been finally determined), either (A) promptly reimburse Tenant the amount of
such excess, or (B) credit the entire amount of such excess against the next
installment of rent becoming due under this Lease.

          (f)  Final Partial Year.  If the Term will expire or this Lease has
               ------------------
been terminated prior to a final determination of Tenant's actual Pro Rata Share
of Operating Costs, the amount of adjustment between Tenant's estimated pro rata
share of such costs and Tenant's actual pro rata share of such costs payable for
the preceding calendar year and/or the final partial calendar year of the Term
will be projected by the Landlord based upon the best data available to Landlord
at the time of the estimate. Within thirty (30) days after receipt of a
statement from Landlord setting forth Landlord's projections, Tenant will pay to
Landlord, or Landlord will pay to Tenant, as the case may be, the difference
between Tenant's projected actual Pro Rata Share of Operating Costs for the
period in question and Tenant's estimated Pro Rata Share of Operating Costs paid
by Tenant for the period in question. Notwithstanding the foregoing, Tenant
shall have the right to require that the adjustment be based upon the actual
Operating Costs, in which event the adjustment shall be delayed until the actual
Operating Costs are determined. The obligations set forth in the preceding
sentence will survive the Expiration Date or earlier termination of this Lease.

          (g)  Adjustment for Occupancy. During any calendar year in which the
               ------------------------
Building has less than full occupancy, Operating Costs will be computed as
though the Building had been completely occupied for the entire calendar year.

     3.3  Personal Property Taxes. Tenant agrees to pay, before delinquency, all
          -----------------------
taxes, fees or charges, rates, duties and assessments, imposed, levied or
assessed directly against Tenant, or indirectly through Landlord, and payable
during the Term hereof, upon Tenant's equipment, furniture, movable trade
fixtures and other

                                Part Two-Page 5

<PAGE>

personal property located in the Premises. Tenant will also pay, before
delinquency, business and other taxes, fees or charges, rates, duties and
assessments imposed, levied or assessed because of the Tenant's occupancy of the
Premises or upon the business or income of the Tenant generated from the
Premises.

     3.4  Late Payments. Should Tenant fail to pay any installment of Base Rent
          -------------
on or before the tenth (10th) day of each calendar month, Interest (as
hereinafter defined) will accrue from the date on which such sum is due and such
Interest, together with a "Late Charge" (herein so called) in an amount equal to
five percent (5%) of the installment then due, will be paid by Tenant to
Landlord at the time of payment of the delinquent sum. The Late Charge is agreed
by Landlord and Tenant to be a reasonable estimate of the extra administrative
expenses incurred by Landlord in handling such delinquency.

     3.5  Interest.  Whenever reference is made in this Lease to the accrual of
          --------
interest on sums due Landlord or whenever any amount owed to Landlord is not
paid when due, such sum will bear interest ("Interest") at an annual rate equal
to the lesser of (i) two percent (2%) over the "base" or "prime" rate published
from time to time by Bank of America, N.A., or (ii) the maximum lawful rate.

     3.6  Administrative Reimbursement.  In the event Landlord performs
          ----------------------------
construction, maintenance, or repairs for Tenant under Sections 7.3 or 12.2 of
                                                       ------------    ----
Part Two of this Lease or incurs expenses under Section 8.5 of Part Two of this
                                                -----------
Lease, Tenant will reimburse Landlord within ten (10) days after receipt of an
invoice from Landlord for the cost of such construction, maintenance or repairs
plus an amount equal to five percent (5%) of such costs ("Administrative
Reimbursement") to reimburse Landlord for administration and overhead.

     3.7  Additional Rent. Any payments to be made by Tenant to Landlord under
          ---------------
this Lease in addition to the Base Rent, whether or not denominated as rent,
will be deemed to be additional rent under this Lease for the purpose of
securing their collection and will constitute rent for purposes of Section 502
of the Bankruptcy Code. Landlord will have the same rights and remedies upon
Tenant's failure to make such payments as for the nonpayment of Base Rent.

4.   SYSCO CORPORATION LEASE
     -----------------------

     Reference is made to the Lease Agreement (the "Sysco Lease") dated July 20,
1998 by and between Enclave Parkway Realty, Inc., as Landlord, and SYSCO
Corporation, as Tenant. Tenant agrees that it has a copy of the Sysco Lease and
that Tenant's rights under this Lease are subject to the rights of the Tenant
under the Sysco Lease, including without limitation those rights under Section
6(d) and 24 and Exhibit E of the Sysco Lease.

5.   SERVICES AND UTILITIES
     ----------------------

     5.1  Services by Landlord. Subject to the conditions and standards set
          --------------------
forth in this Lease and to standards, limitations and guidelines imposed by
governmental authorities and utility companies, Landlord will furnish or cause
to be furnished the following services and utilities: (i) heat and air
conditioning to the Premises during "Normal Business Hours" (as defined in the
Rules and Regulations), at such temperatures and in such quantities as Landlord
reasonably determines are reasonably necessary for the comfortable use

                                Part Two-Page 6
<PAGE>

and occupancy of the Premises for general office purposes and as is consistent
with the operation of a first class office building in the Houston metropolitan
area; (ii) water at the normal temperature of the supply of water to the
Building for lavatory and drinking purposes through fixtures installed by
Landlord or by Tenant with Landlord's consent; (iii) janitorial cleaning
services to those portions of the Premises which are used for office purposes
five (5) days per week (except on holidays observed by the Building); (iv)
cleaning of the carpet in the Premises at least two (2) times each calendar
year; (v) twenty-four (24) hour, nonexclusive passenger elevator service and,
when scheduled through the Building management, nonexclusive freight elevator
service to the floor(s) on which the Premises are located; (vi) routine
maintenance in the Common Areas to maintain such areas in good condition and
repair; (vii) replacement of standard light bulbs, fluorescent tubes, and
ballasts in the Premises; (viii) electric current to the Premises for standard
office lighting and office machines which consume electric current within the
parameters set forth in Section 5.3(a)(i) of this Lease; and (x) building
                        -----------------
security. All services referred to in this Section 5.1 shall be provided by
Landlord and (subject to the provisions of Exhibit C) paid for by Tenant as part
of Tenant's payment of Tenant's Pro Rate Share of Electrical Costs and Pro Rata
Share of Operating Costs.

     5.2  Tenant's Obligations.  Tenant will pay for, prior to delinquency, all
          --------------------
telephone charges and all other materials and services not expressly the
obligation of Landlord that are furnished to or used on or about the Premises
during the Term of this Lease.

     5.3  Tenant's Additional Service Requirements.
          ----------------------------------------

          (a)  Additional Services Requiring Landlord Consent.  Tenant will not,
               ----------------------------------------------
without Landlord's prior written consent, such consent not to be unreasonably
withheld or delayed, do the following: (i) install or use special lighting
beyond Building standard, or any equipment, machinery, or device in the Premises
which requires a nominal voltage of more than one hundred twenty (120) volts
single phase, or which in Landlord's reasonable opinion exceeds the capacity of
existing feeders, conductors, risers, or wiring in or to the Premises or
Building, or which requires amounts of water in excess of that usually furnished
or supplied for use in office space, or which will decrease the amount or
pressure of water or the amperage or voltage of electricity Landlord can furnish
to other occupants of the Building; (ii) install or use any heat or cold-
generating equipment, machinery or device which affects the temperature
otherwise maintainable by the heat or air conditioning system of the Building;
(iii) use portions of the Premises for special purposes requiring greater or
more difficult cleaning work than office areas, such as, but not limited to,
interior glass partitions, and non-Building standard materials or finishes; or
(iv) accumulate refuse or rubbish (A) in excess of that ordinarily accumulated
in business office occupancy or (B) at times other than the Building's standard
cleaning times.

          (b)  Providing Additional Services.  If, in the reasonable opinion of
               -----------------------------
Landlord, additional services to Tenant are necessary, Landlord will have the
following rights:

               (i)  Removal by Tenant. Landlord may require that Tenant cease
                    -----------------
the activity or

                                Part Two-Page 7
<PAGE>

remove the item (or refuse to permit the activity or installation of the item),
causing (or which will cause) the need for such additional service, if Landlord
and Tenant are not able to agree upon a mutually satisfactory method for
providing such additional services or, in the reasonable opinion of Landlord,
providing such additional service is not operationally or economically feasible.

          (ii)  Separate Metering. Landlord may, at Landlord's expense, install
                -----------------
and maintain separate metering devices. Landlord agrees that it will, at the
request of Tenant, cause separate metering devices to be installed to monitor
electricity usage in the Premises, and in such event the cost of such meters and
their installation, maintenance and repair shall be the obligation of Tenant.
Landlord may also cause periodic usage surveys to be prepared by an engineer
employed by Landlord for such purpose, the cost of which shall be included in
Operating Costs.

          (iii) Additional HVAC. With respect to heat or cold generating
                ---------------
equipment, Landlord may furnish additional heat or air conditioning to the
Premises, or install supplementary heating or air conditioning units in the
Premises or elsewhere in the Building, or modify the existing heating or air
conditioning system in the Premises so long as the quality of such services is
not diminished.  The actual cost of additional heat or air conditioning,
supplementary units, or modifications to the existing system specifically made
for the Premises at the request of Tenant will be the obligation of Tenant.

          (iv)  Replacement Bulbs. With respect to lighting requested by Tenant
                -----------------
beyond standard lighting used throughout the Building, Landlord may purchase and
replace, at the expense of Tenant, light bulbs and ballasts and/or fixtures.

          (v)   Additional Janitorial Services. With respect to additional
                ------------------------------
cleaning work, Landlord may instruct Landlord's janitorial contractor to provide
such services and the cost of such service will be the obligation of Tenant.

          (vi)  Substitution of Cleaning Contractors. In the event that Tenant,
                ------------------------------------
in its reasonable judgment, is dissatisfied with the janitorial service provided
in the Premises by Landlord's cleaning contractor, Tenant shall send written
notice thereof (a "Janitorial Complaint Notice") to Landlord stating with
particularity the basis for such dissatisfaction. If Landlord fails to cure the
cited problem with the janitorial service to Tenant's reasonable satisfaction
within fifteen (15) days after receiving a Janitorial Complaint Notice, then
Landlord shall allow Tenant to contract directly with a cleaning company
reasonably acceptable to Landlord for the provision of janitorial services to
the Premises. In such event, Tenant shall pay the cost of janitorial services to
the Premises and the cost of janitorial services included in Operating Costs
under this Lease shall be limited to the cost of janitorial services in the
Common Areas.

     (c)  After Hours Heat or Air Conditioning.  Landlord will use reasonable
          ------------------------------------
efforts to provide after hours heat or air conditioning, at the cost of Tenant,
upon request from Tenant received no later than 3:00 p.m. on a week day for
service required the same night (or prior to business hours of the following
day) or 3:00 p.m. of the last business day before a weekend or a holiday for
service required on a weekend or holiday.  The cost of after hours heat

                                Part Two-Page 8
<PAGE>

or air conditioning charged to Tenant will equal the actual cost to Landlord of
providing such after hours heat or air conditioning.

          (d)  Payment.  Tenant will pay to Landlord the cost of any additional
               -------
service and any other cost for which Tenant is obligated under Section 5.3(b) or
                                                               --------------
(c) within thirty (30) days after receipt of an invoice with respect to same
---
from Landlord.

     5.4  Interruption of Utility Service.  Landlord will use Landlord's best
          -------------------------------
efforts to provide the services required of Landlord under this Lease. However,
Landlord reserves the right, without any liability to Tenant and without
affecting Tenant's covenants and obligations under this Lease, to stop or
interrupt or reduce any of the services listed in Section 5.1 or to stop or
                                                  -----------
interrupt or reduce any other services required of Landlord under this Lease,
whenever and for so long as may be necessary (provided that Landlord shall use
its best efforts to minimize any disruption of or interference with Tenant's use
and occupancy of the Premises, with the additional expense thereof to be
included in Operating Costs) by reason of (i) accidents or emergencies, (ii) the
making of repairs or changes which Landlord in good faith deems necessary or is
required or is permitted by this Lease or is required by law to make, (iii)
inability to secure proper supplies of fuel, water, electricity, labor or
supplies, (iv) the compliance by Landlord with governmental, quasi-governmental
or utility company energy conservation measures, or (v) the exercise by Landlord
of any right under Section 6.5.  Landlord will, in the event of an interruption
                   -----------
of a utility service, use Landlord's best efforts to cause such service to be
resumed. However, no interruption or stoppage of any of such services will ever
be construed as an eviction of Tenant nor will such interruption or stoppage
cause any abatement of the rent payable under this Lease or in any manner
relieve Tenant from any of Tenant's obligations under this Lease; provided,
that, subject to Section 12.7 of Part Two of this Lease, Tenant shall be
                 ------------
entitled to an appropriate abatement of Base Rent and additional rent if there
is an interruption or stoppage of any of such services for a period of five (5)
days or more and Landlord is not using its best efforts to restore such
services.

6.   OCCUPANCY AND CONTROL
     ---------------------

     6.1  Use. The Premises will be used and occupied by Tenant for general
          ---
office and related purposes and for no other purposes. In no event will the term
"general office purposes" be construed to include a public educational facility
or public school, a telemarketing operation or a personnel agency, except with
the consent of Landlord, which consent shall not be unreasonably withheld.

     6.2  Access to the Building and Premises; Telephone System.
          -----------------------------------------------------

          (a)  Landlord shall furnish Tenant, at no cost to Tenant, one (1) card
key to the Premises for each employee of Tenant working in the Premises;
however, Tenant shall be required to pay a reasonable fee determined by Landlord
for any replacement card keys.

          (b)  Notwithstanding anything to the contrary contained in the Rules
and Regulations (as hereinafter defined), Tenant shall have the right, at its
sole cost and expense, to control access to the Premises through the use of
locks,card key or other access systems; provided,

                                Part Two-Page 9
<PAGE>

however, that Landlord shall have the right to approve the design and
installation of such system (which approval shall not be unreasonably withheld)
and provided further that Landlord shall always be furnished with such keys,
electronic keys, key cards, access codes, or similar access devices as are
necessary to provide Landlord with access to the Premises.

          (c)  Tenant shall have the right, at its sole cost and expense, to
install its own telephone and other communications systems in the Premises;
provided, however, that Landlord shall have the right to approve the design and
installation of such systems (which approval shall not be unreasonably
withheld).

     6.3  Rules and Regulations. Tenant's use of the Premises and the Common
          ---------------------
Areas will be subject at all times during the Term to the "Rules and
Regulations" attached to the Lease as Exhibit D and to any modifications of such
                                      ---------
Rules and Regulations and any additional Rules and Regulations from time to time
promulgated by Landlord in Landlord's reasonable discretion (the "Rules and
                                                                  ---------
Regulations"). Additional Rules and Regulations will not become effective and a
-----------
part of this Lease until a copy of same has been delivered to Tenant.  The
inability of Landlord to cause another occupant of the Building to comply with
the Rules and Regulations will neither excuse Tenant's obligation to comply with
such Rules and Regulations or any other obligation of Tenant under this Lease
nor the Landlord to be liable to Tenant for any damage resulting to Tenant.
Tenant will use reasonable efforts to cause Tenant's employees, servants and
agents to comply with the Rules and Regulations.

     6.4  Additional Covenants of Tenant.
          ------------------------------

          (a)  Laws, Statutes. As respects the interior of the Premises, Tenant
               --------------
will, at Tenant's sole cost, promptly comply with (i) all laws, orders,
regulations, and other government requirements now in force or hereafter enacted
relating to the use, condition, or occupancy of the Premises, including without
limitation, (A) Title III of The Americans with Disabilities Act of 1990, all
regulations issued thereunder, and the Accessibility Guidelines for Buildings
and Facilities issued pursuant thereto, and the Texas Architectural Barriers
Act, as the same are in effect on the date of this Lease and as hereafter
amended ("Disabilities Acts"), and (B) all applicable laws, ordinances, and
regulations (including consent orders and administrative orders) relating to
public health and safety and protection of the environment and regulation of
"Hazardous Substances", as such term is defined in Article 21 of the General
                                                   ----------
Lease Provisions ("Environmental Laws"), and (ii) all rules, orders, mandates,
directives, regulations and requirements pertaining to the use of the Premises
and the conduct of Tenant's business imposed by Landlord's insurers, American
Insurance Association (formerly known as "National Board of Fire Underwriters")
or insurance service office, any utility company serving the Building or any
other similar body having jurisdiction over the Building, any related parking
areas, and the Premises.  The foregoing provisions of this Section 6.4(a) shall
                                                           --------------
in no event be construed to require Tenant to make any modifications to the
Building or  any improvements other than the interior of the Premises which may
be required by applicable laws, orders, regulations and other governmental
requirements, it being agreed that Landlord shall be responsible for such

                               Part Two-Page 10
<PAGE>

modifications subject to the provisions of Article 3 and Exhibit C.

          (b)  Nuisance.  Tenant will not do or permit anything to be done in or
               --------
about the Premises which will in any way obstruct or interfere with the
operation of the Project or with the rights of other tenants or occupants of the
Project or injure, disturb or annoy other tenants or occupants of the Project.

          (c)  Building Reputation. Tenant will not use or permit the Premises
               -------------------
to be used for any objectionable purpose or any purpose which, in the reasonable
opinion of the Landlord, harms or tends to harm the business or reputation of
the Landlord or the Building or reflects unfavorably on the Building, or any
part of the Building, or deceives or defrauds the public.

          (d)  Recording. Neither Landlord nor Tenant will record this Lease or
               ---------
any memorandum of this Lease without the prior written consent of the other
party. Either Landlord or Tenant will, upon request of the other party, execute,
acknowledge and deliver to the other party a short form or memorandum of this
Lease for recording purposes.

     6.5  Access by Landlord.  Landlord reserves the right for Landlord and
          ------------------
Landlord's agents to enter the Premises at any reasonable time, upon reasonable
prior notice to Tenant:  (a) to inspect the Premises (which inspections shall
beconducted during business hours except in the event of an emergency), (b) to
supply janitorial service or other services to be provided by Landlord to Tenant
under this Lease, (c) to show the Premises to prospective lenders or purchasers,
(d) to maintain or repair any portions of the Premises for which Landlord is
responsible or any other portion of the Building abutting the Premises, (e) to
install, maintain, repair, replace or relocate any pipe, duct, conduit, wire or
equipment serving other portions of the Building but located in the ceiling,
wall or floor of the Premises, (f) to perform any other obligation of Tenant
after 30 days notice (or, in the case of an emergency, after such written or
oral notice and opportunity to cure as may be reasonable under the
circumstances) to Tenant of Tenant's failure to perform same, or (g) upon
default by Tenant under this Lease.  Furthermore, during the last six (6) months
of the Term, Landlord and Landlord's agents shall have the right to enter the
Premises at any reasonable time, upon reasonable prior notice to Tenant, to show
the Premises to prospective tenants.  If Landlord enters the Premises for the
purpose of performing work, Landlord may erect scaffolding and store tools,
material, and equipment in the Premises when required by the character of the
work to be performed.

     6.6  Control of Project. The Building and Common Areas will be at all times
          ------------------
under the exclusive control, management and operation of the Landlord. Landlord
hereby reserves the right from time to time to close temporarily doors, entry
ways, public spaces and corridors and to interrupt or suspend temporarily
Building services and facilities in order to perform any redecorating or
alteration or in order to prevent the public from acquiring prescriptive rights
in the Common Areas. Landlord agrees that the number of parking spaces available
to tenants of the Project shall in all events comply with applicable parking
ordinances.

     6.7  Minimization of Disruption. Landlord will attempt not to disrupt
          --------------------------
Tenant's operations in the Premises during the exercise of Landlord's rights or
the performance by Landlord of

                               Part Two-Page 11
<PAGE>

Landlord's obligations under this Lease, but will not be required to incur
extra expenses in order to minimize such disruption. No exercise by Landlord of
any right or the performance by Landlord of Landlord's obligations under this
Lease will constitute actual or constructive eviction or a breach of any express
of implied covenant for quiet enjoyment.

7.   REPAIRS, MAINTENANCE AND ALTERATIONS
     ------------------------------------

     7.1  Landlord's Repair Obligations.  Landlord will, subject to the casualty
          -----------------------------
provisions of Article 9, maintain (a) the Common Areas and Service Areas, (b)
              ---------
roof, foundation, exterior windows and load bearing items of the Building; (c)
exterior surfaces of walls; (d) plumbing, pipes and conduits located in the
Common Areas or Service Areas of the Building, and (e) the Building central
heating, ventilation and air conditioning, electrical, mechanical and plumbing
systems.  Landlord will not be required to make any repair in connection with or
resulting from (i) any alteration or modification to the Premises or to Building
equipment performed by or on behalf of Tenant or to special equipment or systems
installed by or on behalf of Tenant, (2)the installation, use or operation of
Tenant's property, fixtures and equipment, (3) the moving of Tenant's property
in or out of the Building or in and about the Premises, (4) Tenant's use or
occupancy of the Premises in violation of Article 6 or in a manner not
                                          ---------
contemplated by the parties at the time of execution of this Lease (e.g.,
subsequent installation of special use rooms), (5) the acts or omissions of
Tenant and Tenant's employees, agents, invitees, subtenants, licensees or
contractors, (6) fire or other casualty, except as provided in Article 9, or (7)
                                                               ---------
condemnation, except as provided in Article 10.  Depending upon the nature of
                                    ----------
repairs undertaken by Landlord, the cost of such repairs will be borne solely by
Landlord or reimbursed to Landlord either by a particular tenant or tenants or
by all tenants as an Operating Cost as provided in this Lease.

     7.2  Tenant's Repair Obligations.  Except for janitorial services and
          ---------------------------
Landlord's services pursuant to Section 7.1 above provided by Landlord, Tenant,
at Tenant's expense, will maintain the Premises in good order, condition and
repair, subject to ordinary wear and tear (which wear and tear Lessee also shall
maintain as aforesaid at such time as such wear and tear would customarily
require such maintenance), including, without limitation, the interior surfaces
of the windows, walls and ceilings; floors; wall and floor coverings; window
coverings; doors; interior windows; and all switches, fixtures and equipment in
the Premises.  Upon receipt of reasonable notice from Tenant, Landlord will
perform, at the expense of Tenant, all repairs and maintenance to plumbing,
pipes and electrical wiring located within walls, above ceilingsurfaces and
below floor surfaces resulting from the use of the Premises by Tenant.  In no
event will Tenant be responsible for any plumbing, pipes and electrical wiring,
switches, fixtures and equipment located in the Premises but serving another
tenant or for portions of the central heat, ventilation and air conditioning,
electrical, mechanical and plumbing systems of the Building which are located in
the Premises, except for (i) repairs resulting from the acts of Tenant and
Tenant's employees, agents, invitees, subtenants, licensees or contractors, (ii)
modifications made to such systems by or on behalf of Tenant, and (iii) special
equipment installed by or on behalf  of Tenant.

                               Part Two-Page 12
<PAGE>

     7.3  Rights of Landlord. In the event Tenant fails after written notice and
          ------------------
30 days opportunity to cure (or, in the case of an emergency, after such written
or oral notice and opportunity to cure as may be reasonable under the
circumstances), in the reasonable judgment of Landlord, to maintain the Premises
in good order, condition and repair, Landlord will have the right to perform
such maintenance, repairs, refurbishing or repairing at Tenant's expense.

     7.4  Surrender. Upon the expiration or earlier termination of this Lease,
          ---------
or upon the exercise by Landlord of Landlord's right to re-enter the Premises
without terminating this Lease, Tenant will surrender the Premises in the same
condition as received or as subsequently improved by Landlord or Tenant, except
for (i) ordinary wear and tear and (ii) damage by fire, earthquake, acts of God
or the elements, and will deliver to Landlord all keys for the Premises and
Garage and combinations to safes located in the premises. Tenant will remove, or
cause to be removed, from the Premises or the Building, at Tenant's expense and
as of the Expiration Date or earlier termination of this Lease, all signs
(including any signs located on the Premises, i.e., building or monument signs),
notices, displays, and trade fixtures of Tenant. Tenant agrees to repair, at
Tenant's expense, any damage to the Premises or any other part of the Project
resulting from the removal of any articles of personal property, movable
business or trade fixtures, machinery, equipment, furniture or movable
partitions, including without limitation, repairing the floor and patching and
painting the walls where required by Landlord. Tenant's obligations under this
Section 7.4 will survive the expiration or earlier termination of this Lease.
-----------
If Tenant fails to remove any item of property permitted or required to be
removed at the expiration or earlier termination of the Term, Landlord, may, at
Landlord's option, (a) remove such property from the Premises at the expense of
Tenant and sell or dispose of same in such manner as Landlord deems advisable,
or (b) place such property in storage at the expense of Tenant.  Any property of
Tenant remaining in the Premises ten (10) days after the Expiration Date or
earlier termination of this Lease without the written consent of Landlord will
be deemed to have been abandoned by Tenant.

     7.5  Alterations by Tenant.
          ---------------------

          (a)  Approval Required. Tenant will not make, or cause or permit to be
               -----------------
made, any additions, alterations, installations or improvements in or to the
Premises (collectively, "Alterations"), without the prior written consent of
Landlord, provided, however, that in the case of non-structural Alterations
proposed by Tenant, Landlord's consent shall not be required. Unless Landlord
has waived such requirement in writing, together with Tenant's request for
approval of any Alteration (other than a non-structural Alteration), Tenant must
also submit details with respect to the proposed source of funds for the payment
of the cost of the Alteration by Tenant, design concept, plans and
specifications, names of proposed contractors, and financial and other pertinent
information about such contractors (including without limitation, the labor
organization affiliation or lack of affiliation of any contractors),
certificates of insurance to be maintained by Tenant's contractors, hours of
construction, proposed construction methods, details with respect to the quality
of the proposed work and evidence of security (such as payment and performance
bonds) to assure timely completion of the work by the contractor and payment by
the contractor of all costs of the

                               Part Two-Page 13
<PAGE>

work. With respect to any Alteration which is visible from outside the Premises,
such proposed Alteration shall, in the opinion of Landlord, also be
architecturally and aesthetically harmonious with the remainder of the Building.

          (b)  Complex Alterations.  If the nature, volume or complexity of any
               -------------------
proposed Alterations causes Landlord to consult with an independent architect,
engineer or other consultant, Tenant will reimburse Landlord for the reasonable
fees and expenses incurred by Landlord.  If any improvements will affect the
basic heat, ventilation and air conditioning or other Building systems or the
Building, Landlord may require that such work be designed by consultants
designated by Landlord and be performed by Landlord or Landlord's contractors.

          (c)  Standard of Work. All work to be performed by or for Tenant
               ----------------
pursuant hereto will be performed diligently and in a first-class, workmanlike
manner, and in compliance with all applicable laws, ordinances, regulations and
rules of any public authority having jurisdiction over the Project and/or
Tenant, including, without limitation, the Disabilities Acts, Environmental
Laws, and Landlord's insurance carriers. Landlord will have the right, but not
the obligation, to inspect periodically the work on the Premises and may require
changes in the method or quality of the work to comply with the provisions of
this Section 7.5(c).

          (d)  Ownership of Alterations.  All Alterations made by or for Tenant
               ------------------------
(other than Tenant's trade fixtures) will immediately become the property of
Landlord, without compensation to Tenant.  Carpeting will be deemed improvements
of the Premises and not trade fixtures, regardless of how or where affixed. Such
Alterations will not be removed by Tenant from the Premises either during or at
the expiration or earlier termination of the Term and will be surrendered as a
part of the Premises unless Landlord has requested that Tenant remove such
Alterations.

     7.6  Liens. Tenant will keep the Premises and the Building free from any
          -----
liens arising out of work performed, materials furnished, or obligations
incurred by or on behalf of or for the benefit of Tenant. If Tenant does not,
within ten (10) days following notice of the imposition of any such lien, cause
such lien to be released of record by payment or posting of a proper bond or
other security, Landlord will have, in addition to all other remedies provided
in this Lease and by law, the option, to cause the same to be released by such
means as Landlord deems proper, including payment of the claim giving rise to
such lien. All sums paid and expenses incurred by Landlord in connection
therewith, including reasonable attorneys' fees and a reasonable amount for
Landlord's administrative time, will be payable to Landlord by Tenant on demand
with Interest from the date such sums are expended.

8.   INSURANCE
     ---------

     8.1  Insurance Required of Tenant.  Tenant will, at Tenant's sole expense,
          ----------------------------
procure and maintain the coverages required by this Section 8.1.
                                                    -----------

          (a)  Commercial General Liability Insurance.  Tenant will procure and
               --------------------------------------
maintain commercial general liability insurance ("Liability Insurance") written
on an "occurrence" policy form, covering bodily injury, property damage and
personal injury arising out of or relating, directly or indirectly, to Tenant's
business

                               Part Two-Page 14
<PAGE>

operations, conduct, assumed liabilities or use or occupancy of the Premises or
any other part of the Project. Tenant will cause Landlord and any lender of
Landlord as to which Tenant has been provided notice to be named as "additional
insureds." The minimum acceptable limits for Tenant's Liability Insurance are
set forth in Paragraph 8 of the Basic Lease Provisions.
             -----------

          (b)  Workers' Compensation and Employer Liability Coverage. Tenant
               -----------------------------------------------------
will procure and maintain workers' compensation insurance as required by law and
employer's liability insurance with limits of no less than the amount set forth
in Paragraph 8 of the Basic Lease Provisions.
   -----------

          (c)  Property Insurance.  Tenant will procure and maintain property
               ------------------
insurance coverage ("Property Insurance") for the following: (i) all office
furniture, trade fixtures, office equipment, merchandise and all other items of
Tenant's personal property in, on, at or about the Premises or any other part of
the Project; and (ii) all leasehold improvements to the Premises and other
improvements, betterments, and Alterations to the Premises.  Tenant's Property
Insurance must be written on an "all-risk" (special-causes-of-loss)  policy form
or an equivalent form, include an agreed-amount endorsement for no less than one
hundred percent (100%) of the full replacement cost (new without deduction for
depreciation) of the covered items and property; be written in amounts of
coverage that meet any coinsurance requirements of the policy or policies, and
include vandalism and malicious mischief coverage, and sprinkler leakage
coverage.  Each of Landlord and any lender of Landlord as to which Tenant has
been provided notice must be named as an "insured as its interest may appear"
under Tenant's Property Insurance.

          (d)  Business Income and Extra Expense Coverage. Tenant will also
               ------------------------------------------
procure and maintain business income /business interruption insurance and extra
expense coverage (collectively, "Interruption Insurance") with coverage
amountsthat will reimburse Tenant for all direct or indirect loss of income and
charges and costs incurred arising out of all perils insured against by Tenant's
Property Insurance coverage, including prevention of, or denial of use of or
access to, all or part of the Premises or the Building, as a result of those
perils. The Interruption Insurance coverage must provide coverage for no less
than twelve (12) months of the loss of income, charges, and costs contemplated
under the Lease.

     8.2  Landlord's Insurance.  Landlord will, during the Term of this Lease,
          --------------------
procure and continue in force the following insurance: (a) liability insurance
written on an "occurrence" policy form, covering bodily injury, property damage
and personal injury arising out of or relating, directly or indirectly, to
Landlord's business operations, conduct, assumed liability or use or occupancy
of the Project, with a combined single limit of not less than Two Million
Dollars ($2,000,000), it being agreed that Landlord will cause Tenant to be
named as an "additional insured"; and (b) property insurance covering the
Building and all personal property  located in the Building and all machinery,
equipment and other personal property used in connection with the Building (but
not property owned by any tenant of the Building or for which any tenant of the
Building is legally liable, or alterations, leasehold improvements, or
betterments made, installed or purchased by or on behalf of any tenant of the
Building), which property insurance must be written on an "all-risk" (special-
causes-of-loss) policy from or an equivalent form, include an

                               Part Two-Page 15
<PAGE>

agreed-amount endorsement for no less than one hundred percent (100%) of the
full replacement cost (new without deduction for depreciation) of the covered
items and property; be written in amounts of coverage to meet any coinsurance
requirements of the policy or policies, and include vandalism and malicious
mischief coverage, and sprinkler leakage coverage. Such property insurance shall
also include coverage for lost rental in an amount equal to one year of Base
Rent in the Base Rent amount then in effect. Landlord shall also procure and
maintain workers' compensation insurance as required by law and employer's
liability insurance with limits of not less than One Million Dollars
($1,000,000).

     8.3  Form of Policies and Additional Requirements. The insurance
          --------------------------------------------
requirements set forth in Section 8.1 and Section 8.2 are independent of the
                          -----------     -----------
waiver, indemnification, and other obligations of Tenant and Landlord under this
Lease and will not be construed or interpreted in any way to restrict, limit or
modify Tenant's or Landlord's waiver, indemnification and other obligations or
to in any way limit Tenant's or Landlord's liability under this Lease. In
addition to the requirements set forth in Section 8.1 and Section 8.2, the
                                          -----------     -----------
insurance required of Tenant and Landlord under this Article 8 must (a) be
                                                     ---------
issued by an insurance company with a rating of no less than A-VIII in the
current Best's Insurance Guide, or that is otherwise reasonably acceptable to
Landlord as to Tenant's insurance or to Tenant as to Landlord's insurance, and
admitted to engage in the business of insurance in the State of Texas; and (b)
provide that insurance may not be canceled, nonrenewed or the subject of
material change in coverage or available limits of coverage, except, in the case
of Tenant'sinsurance, upon thirty (30) days' prior written notice (ten (10) days
for non-payment of premium) to Landlord and any lender of Landlord as to which
Tenant has been provided notice, and, in the case of Landlord's insurance, upon
thirty (30) days' prior written notice (ten (10) days for non-payment of
premium) to Tenant. Tenant and Landlord will each deliver to the other a
certificate of insurance on all policies procured by Tenant or Landlord, as the
case may be, in compliance with such party's obligations under this Lease,
together with evidence of the payment of the premiums therefor, on or before the
Lease Commencement Date, and at least thirty (30) days before the expiration
date of any policy and upon the renewal of any policy. Provided that Tenant
receives written notice of the name and address of any lender to Landlord that
is the beneficiary of a deed of trust that encumbers the Premises, Tenant hereby
covenants to provide such lender with a duplicate original certificate of
insurance as required under the preceding sentence. Landlord or Tenant may
comply with its insurance coverage requirements through a blanket policy.

     8.4  Waiver of Subrogation. Landlord and Tenant agree to cause the
          ---------------------
insurance companies issuing their respective property insurance policies to
waive any subrogation rights that those companies may have against Tenant or
Landlord. It is the intent of the parties that with respect to any loss from a
peril required to be covered by property insurance, the parties will look solely
to their insurance companies for recovery. Landlord and Tenant will each deliver
notice of this Section 8.4 to its insurance carriers.
               -----------

     8.5  Increase of Premiums. If Tenant's specific business operations,
          --------------------
conduct or use of the Premises or any other part of the Project causes an
increase in the premium for any insurance policy carried by Landlord, Tenant
will, within ten (10) days after receipt of notice from

                               Part Two-Page 16
<PAGE>

Landlord, reimburse Landlord for the entire increase.

9.   DAMAGE OR DESTRUCTION
     ---------------------

     9.1  Repair by Landlord. Tenant will immediately notify Landlord of fire or
          ------------------
other casualty in the Premises. If the Premises are damaged by fire or other
casualty and unless this Lease is terminated as hereinafter provided, Landlord
will proceed with reasonable diligence to repair the so-called "shell" of the
Premises and any leasehold improvements originally installed by Landlord or
existing on the date Landlord acquired the Building. Landlord's obligation to
repair is subject to (a) delays which may arise by reason of adjustment of loss
under insurance policies, including, without limitation, Tenant's policy for
leasehold improvements and betterments described in Section 8.1 of this Lease,
                                                    -----------
and (b) other delays beyond Landlord's reasonable control. Landlord's obligation
to repair will be limited to the extent of insurance proceeds actually available
to Landlord for repairs after the election by the holder of any mortgage against
the Building to apply a portion or all of the proceeds against the debt owing to
such holder. Until Landlord's repairs to the Premises are completed, the Base
Rent and additional rent will abate in proportion to the part of the Premises,
if any, that is rendered untenantable.

     9.2  Landlord's Rights Upon The Occurrence of Certain Casualties.  In the
          -----------------------------------------------------------
event: (a) either the Premises or the Building (whether or not the Premises are
affected) is totally or partially destroyed or damaged by fire or other casualty
and repairs cannot be completed within  two hundred seventy (270) days after the
occurrence of such damage without the payment by Landlord of overtime or other
premiums; (b) fifty percent (50%) or more of the Rentable Area of the Building
(wherever located) is damaged or destroyed by fire or other casualty (whether or
not the Premises are affected thereby); (c) damage is otherwise so great that
Landlord, in Landlord's absolute discretion, decides to demolish the Building,
in whole or in substantial part; (d) insurance proceeds remaining after payment
of any proceeds required to be paid to the holder of any mortgage affecting the
Project are insufficient to repair or restore the damage or destruction; (e) the
Building or the Premises are damaged or destroyed as a result of any cause other
than the perils covered by Landlord's property insurance; or (f) the Premises
are materially damaged, in Landlord's judgment, by fire or other casualty during
the last twenty-four (24) months of the Term; then  Landlord may elect (i) to
the extent of the insurance proceeds actually received by  Landlord, to proceed
to repair, restore or rebuild the Building and the Premises, in which event this
Lease will continue in effect (subject to Tenant's right to terminate the Lease
as set forth in Section 9.3), or (ii) to terminate this Lease (effective as of
                -----------
the event of destruction) upon thirty (30) days' prior notice to Tenant, which
notice will be given, if at all,within sixty (60) days following the date of the
occurrence of the destruction.  In repairing or restoring the Building or any
part thereof, Landlord may use designs, plans and specifications other than
those used in the original construction of the Building, and the Landlord may
alter or relocate, or both, any or all buildings, facilities and improvements,
including the Premises, provided that the Premises as altered or relocated will
be substantially the same size and will be in all material respects reasonably
comparable to the Premises.  Upon any such termination of this Lease, Tenant
will surrender to Landlord the Premises.  Landlord shall have no

                               Part Two-Page 17
<PAGE>

interest in any proceeds from Tenant's insurance attributable to tenant
improvements constructed by Tenant during the Term of this Lease. Tenant will
pay Base Rent and all other sums payable under this Lease prorated through the
effective date of such termination and Landlord and Tenant will be free and
discharged from all obligations under this Lease arising after the effective
date of such termination, except those obligations expressly stated in this
Lease to survive the termination of this Lease.

     9.3  Tenant's Rights Upon The Occurrence of Certain Casualties. In the
          ---------------------------------------------------------
event that the Premises or any portion thereof is destroyed or damaged by fire
or other casualty and repairs cannot be completed within two hundred seventy
(270) days after the occurrence of such damage without the payment by Landlord
of overtime or other premiums, then Tenant may elect to terminate this Lease
(effective as of the event of destruction) upon thirty (30) days' prior notice
to Landlord, which notice will be given, if at all,within sixty (60) days
following the date of the occurrence of the destruction. Furthermore, in the
event that this Lease remains in effect after destruction or damage to the
Premises and Landlord fails to complete the repair of such destruction or damage
in accordance with Section 9.1 within two hundred seventy (270) days after the
                   -----------
occurrence of such destruction or damage (subject to extension by reason of the
delays described in the third sentence of said Section 9.1) (the "Landlord
                                               -----------
Repair Period"), then Tenant may, as its sole and exclusive remedy, terminate
this Lease (effective as of the expiration of the Landlord Repair Period) by
sending written notice to Landlord, which notice will be given, if at all,
within thirty (30) days after the expiration of the Landlord Repair Period.

     9.4  Repairs by Tenant. Landlord will not be required to repair any injury
          -----------------
or damage by fire or other cause, to restore or replace or to reimburse Tenant
for damage to any of the Tenant's property. Tenant will be required to repair
any injury or damage to Tenant's property in the Premises. Except for abatement,
if any, of Base Rent and additional rent in accordance with the provisions of
this Lease, Tenant will not be entitled to any allowance, compensation or
damages from Landlord for loss of use of all or any part of the Premises or
Tenant's property or for any inconvenience, annoyance, disturbance or loss or
interruption of business, or otherwise, arising from any damage to the Premises
or any other part of the Project by fire or any other cause, or arising from any
repairs, reconstruction or restoration, nor will Tenant have the right to
terminate this Lease except as specifically set forth in Section 9.3.
                                                         -----------

     9.5  Determination or Period Required for Rebuilding.  The determination of
          -----------------------------------------------
whether the repair of damage caused by fire or other casualty can be completed
within the two hundred seventy (270) period referred to in  Section 9.2 and
                                                            -----------
Section 9.3   shall initially be made by Landlord, in Landlord's reasonable
------------
judgement, and notice of such determination shall be sent by Landlord to Tenant
within twenty (20) days after the occurrence of such damage.  Tenant shall be
deemed to have accepted the determination made by Landlord unless Tenant sends
written notice disputing such determination within ten (10) days after receiving
notice of same.  If Tenant timely objects to Landlord's determination, the
parties shall, within ten (10) days thereafter, agree in good faith upon a
mutually acceptable architect to make the determination of whether repair can be
completed within the two hundred seventy (270) day period referred to in
Section 9.2 and Section
-----------     -------

                               Part Two-Page 18
<PAGE>

9.3, which determination shall be made within ten (10) days after the selection
---
of such architect and shall be binding upon the parties.

10.  EMINENT DOMAIN
     --------------

     10.1 Total Taking.  If all of the Project is taken or appropriated for
          ------------
public or quasi-public use by right of eminent domain or transferred by
agreement with such public or quasi-public agency, this Lease will terminate as
of the date possession is taken by the condemning authority. If less than all of
the Premises or Project is taken or appropriated but, in Landlord's reasonable
judgment, the balance will be rendered untenantable, such taking will constitute
a total taking for purposes of this Section 10.1. Landlord will notify Tenant of
                                    ------------
Landlord's decision that the remainder is untenantable within thirty (30) days
of Landlord's receipt of notice of the taking or appropriation and this Lease
will terminate as of the date possession is taken by the condemning authority.

     10.2 Partial Taking.  If only part of the Project (whether or not such part
          --------------
includes the Premises) is taken or appropriated by a public or quasi-public
agency under the right of eminent domain or conveyed in agreement with a public
or quasi-public agency (whether or not the Premises are affected thereby) and,
(i) in Landlord's reasonable judgment, substantial alteration or reconstruction
of the Project is necessary as a result of such taking or conveyance, or (ii) if
Landlord decides to demolish or discontinue operating the Project as a result of
such taking or conveyance, or (iii) twenty-five percent (25%) or more of the
Rentable Area of the Building is so taken or conveyed or, in the reasonable
judgment of Landlord, the Building is rendered untenable as a result, or (iv)
proceeds from such taking or conveyance remaining after payment of any such
proceeds required to be paid to the holder of any mortgage affecting the Project
are insufficient to restore the Project  and the Premises to an architectural
whole, then, in any of such events, Landlord may, at Landlord's option,
terminate this Lease by giving Tenant notice of termination within thirty (30)
days after such taking or conveyance.  In the event that the  Premises or a
portion thereof is taken or appropriated by a public or quasi-public agency
under the right of eminent domain or conveyed in agreement with a public or
quasi-public agency, then Tenant may,at Tenant's option, terminate this Lease by
giving Landlord  notice of termination within thirty (30) days after such taking
or conveyance.  In the event this Lease is not terminated, Landlord will, to the
extent of proceeds actually received after the exercise by any mortgagee of the
Project of an option to apply such proceeds against Landlord's debt to such
mortgagee, restore the Project to an architectural whole.

     10.3 Award.  Any award for or proceeds from any partial or entire taking or
          -----
conveyance to a public or quasi-public agency will be the property of Landlord,
including, without limitation, any award or proceeds based on value of the
leasehold interest of Tenant.  Nothing contained in this Section 10.3 will be
                                                         ------------
deemed to give Landlord any interest in or to preclude Tenant from seeking and
recovering for Tenant's account a separate award from the condemning authority
(but only to the extent such separate award does not reduce any award to
Landlord) for the taking of personal property and fixtures removable by Tenant,
for the interruption of or damage to Tenant's business or Tenant's  or
unamortized cost of leasehold improvements paid for by Tenant or for moving
expenses.  In the event of a partial taking which

                               Part Two-Page 19
<PAGE>

does not result in a termination of this Lease, Base Rent and additional rent
will be abated in the proportion which the Rentable Area of the Premises
rendered unusable bears to the total Rentable Area of the Premises. No temporary
taking of Tenant's Premises and/or of Tenant's rights therein or under this
Lease will terminate this Lease or give Tenant any right to any abatement of
Base Rent or additional rent under this Lease. Any award made to Tenant by
reason of anytemporary taking will belong entirely to Tenant and Landlord will
not be entitled to share in such award.

11.  ASSIGNMENT AND SUBLETTING
     -------------------------

     11.1 Consent.  Except for an assignment to an Affiliate of Tenant, Tenant
          -------
will not assign this Lease without the prior written consent of Landlord, which
consent shall not be unreasonably withheld or delayed.  Tenant may sublet any
portion of the Premises or assign this Lease to an Affiliate without the prior
written consent of Landlord.  For purposes of the preceding sentence, in
determining whether to consent to a proposed assignment, Landlord will be deemed
to be reasonable in taking into consideration, among other factors, (a) the
credit standing and financial wherewithal of the proposed assignee or sublessee;
and  (b) whether the use of the Premises by the proposed assignee will be
consistent with the operation of a first-class office building in the Houston,
Texas area. Any assignment or subletting will not relieve the Tenant or any
guarantor of this Lease from any obligation or liability under this Lease.  If
this Lease is assigned without the consent of Landlord, then Landlord may
nevertheless collect Base Rent and additional rent from the assignee, and apply
the net amount collected to the Base Rent and other amounts payable under this
Lease, but in no event will such collection be construed as a waiver of this
covenant.

     11.2 Definitions of Assignment and Affiliate. The use of the words
          ---------------------------------------
"assignment", "assign", or "assigned" in this Article 11 will include
                                              ----------
thepledging, mortgaging or encumbering of Tenant's interest in this Lease.
Tenant shall deliver to Landlord copies of all documents executed in connection
with any permitted assignment or sublease, which documents (i) in the case of a
permitted assignment, shall require such assignee to assume performance of all
terms of this Lease on Tenant's part to be performed, and (ii) in the case of a
subletting, shall require such sublessee to comply with all terms of this Lease
on Tenant's part to be performed.  In no event shall any assignment, sublease or
transfer, whether or not with Landlord's consent, relieve Tenant of its primary
liability under this Lease for the entire Term, and Tenant shall in no way be
released from the full and complete performance of all the terms hereof.  No
acceptance by Landlord of any rent or any other sum of money from any assignee
or other category of transferee shall be deemed to constitute Landlord's consent
to any assignment or transfer.  The term "Affiliate" shall mean as to any
person, a person Controlling, Controlled by or under common Control with,
directly or indirectly, through one or more intermediaries, such person.
"Control" of a person means (i) the power, directly or indirectly, to (x) elect,
appoint or cause the election or appointment of at least a majority of the
members of the board of directors of such person, or (y) direct or cause the
direction of the management and policies of such Person, or (ii) the ownership,
directly or indirectly, of (x) all or substantially all of the properties and
assets of such person or (y) a majority (by percentage) of the total voting
power of all classes then

                               Part Two-Page 20
<PAGE>

outstanding of the voting stock (or other voting interest) of such person.

12.     DEFAULT; REMEDIES
        -----------------

   12.1 Defaults by Tenant.   The occurrence of any of the following will
        ------------------
constitute a default under this Lease by Tenant: (a) any failure by Tenant to
pay an installment of Base Rent or to make any other payment required under this
Lease when due, where such failure continues for ten (10) days after notice by
Landlord to Tenant, except that Landlord shall in no event be required to give
more than two (2) notices of a recurring failure during each calendar year; (b)
any failure by Tenant to observe and perform any other provision of this Lease
to be observed and performed by Tenant, where such failure continues for thirty
(30) days after notice by Landlord to Tenant (provided, however, that if the
cure of such act or omission requires, despite the use of diligent efforts, a
period in excess of thirty (30) days, then such thirty (30) day period shall be
extended for so long as Tenant pursues the cure thereof with reasonable
diligence), except that Landlord shall in no event be required to give more than
two (2) notices of a recurring failure during each calendar year; (c) Tenant's
interest in this Lease or in all or a part of the Premises is taken by process
of law directed against Tenant, or becomes subject to any attachment at the
instance of any creditor of or claimant against Tenant, and such attachment is
not discharged within ten (10) days; (d)  Tenant: (i) is unable to pay such
party's debts generally as they become due; (ii) makes an assignment of all or a
substantial part of such party's property for the benefit of creditors; (iii)
convenes or attends a meeting of such party's creditors, or any class thereof,
for purposes of effecting a moratorium upon or extension or composition of such
party'sdebts; (iv) applies for or consents to or acquiesces in the appointment
of a receiver, trustee, liquidator, or custodian of such party or of all or a
substantial part of such party's property or of the Premises or of Tenant's
interest in this Lease; or (v) files a voluntary petition in bankruptcy or a
petition or an answer seeking reorganization under the Bankruptcy Code or any
other law relating to bankruptcy, insolvency, reorganization or relief of
debtors or an arrangement with creditors, or takes advantage of any insolvency
law or files an answer admitting the material allegations of a petition filed
against such party in any bankruptcy, relief, reorganization or insolvency
proceedings; (e) Tenant takes any corporate action to authorize any of the
actions set forth in Section 12.1(d); or (f) the entry of a court order,
                     ---------------
judgment or decree against Tenant, without the application, approval or consent
of Tenant, approving a petition seeking reorganization of Tenant or relief of
debtors under the Bankruptcy Code or any other law relating to bankruptcy,
insolvency, reorganization, or relief of debtors or granting an order for relief
against it as debtor or appointing a receiver, trustee, liquidator, or custodian
of such party or of all or a substantial part of Tenant's property or of the
Premises or of Tenant's interest in this Lease, or adjudicating such party
bankrupt or insolvent, and such order, judgment or decree will not be vacated,
set aside or dismissed within ninety (90) days from the date of entry.

   12.2 Remedies.  Upon the occurrence of any event of default enumerated in
        --------
Section 12.1, Landlord will have the option of (a) terminating this Lease by
------------
notice thereof to Tenant or (b) continuing this Lease in full force and
effectand/or (c) performing the obligation of Tenant and/or (d) changing locks.

                               Part Two-Page 21
<PAGE>

          (a)  Termination of Lease.  In the event Landlord elects to terminate
               --------------------
this Lease, upon notice to Tenant this Lease will end as to Tenant and all
persons holding under Tenant, and all of Tenant's rights will be forfeited and
lapsed, as fully as if this Lease had expired by lapse of time, and there will
be recoverable from Tenant: (i) the cost of restoring the Premises to good
condition, normal wear and tear excepted, (ii) all accrued, unpaid sums, plus
Interest and late charges, if in arrears, under the terms of this Lease up to
the date of termination, (iii) Landlord's reasonable costs of recovering
possession of the Premises, and (iv) if Tenant remains in possession of the
Premises subsequent to the date of termination, rent and other sums accruing
subsequent to the date of termination pursuant to the holdover provisions of
Section 2.3. The Landlord will at once have all the rights of re-entry upon the
-----------
Premises, without becoming liable for damages, or guilty of a trespass.

          (b)  Continuation of Lease.  In the event that Landlord elects to
               ---------------------
continue this Lease in full force and effect, Tenant will continue to be liable
for all rents. Landlord will nevertheless have all the rights of re-entry upon
the Premises without becoming liable for damages, or guilty of a trespass.
Landlord, after re-entry, may relet all or a part of the Premises to a
substitute tenant or tenants, for a period of time equal to or less or greater
than the remainder of the Term on whatever terms and conditions Landlord, at
Landlord's sole discretion, deems advisable. Against the rents and sums due from
Tenant toLandlord during the remainder of the Term, credit will be given Tenant
in the net amount of rent received from the new tenant after deduction by
Landlord for: (i) the reasonable costs incurred by Landlord in reletting the
Premises (including, without limitation, remodeling costs, brokerage fees, and
the like), (ii) the accrued sums, plus Interest and late charges if in arrears,
under the terms of this Lease, (iii) Landlord's cost of recovering possession of
the Premises, and (iv) if Landlord elects to store Tenant's property in
accordance with Section 7.4, the cost of storing any of Tenant's property
                -----------
left on the Premises after re-entry. Notwithstanding any provision in this
Section 12.2(b) to the contrary, upon the default of any substitute tenant or
---------------
upon the expiration of the term of such substitute tenant before the expiration
of the Term hereof, Landlord may, at Landlord's election, either relet to
another substitute tenant, or terminate this Lease and exercise Landlord's
rights under Section 12.2(a) of this Lease.
             ---------------

          (c)  Performance for Tenant.  In the event that Landlord elects to
               ----------------------
perform the obligation(s) of Tenant, all reasonable sums expended by Landlord
effecting such performance (including Administrative Reimbursement under
Section 3.8), plus Interest thereon, will be due and payable with the next
------------
monthly installment of Base Rent. Such sum will constitute additional rental
under this Lease, and failure to pay such sums when due will enable Landlord to
exercise all of Landlord's remedies under this Lease.

          (d)  Changing Locks.  Additionally, upon the occurrence of an event of
               --------------
default, Landlord may without notice alter locks or other securitydevices at the
Premises to deprive Tenant of access to the Premises, and Landlord will not be
required to provide a new key or rights of access to Tenant.

    12.3  Remedies Cumulative.  All rights and remedies of Landlord under this
          -------------------
Lease will be nonexclusive of and in addition to any other

                               Part Two-Page 22
<PAGE>

remedies available to Landlord at law or in equity.

  12.4   Default by Landlord.  The failure of Landlord to observe and perform
         -------------------
any provision of this Lease to be observed and performed by Landlord, where such
failure continues for thirty (30) days after notice by Tenant to Landlord
(provided, however, that if the cure of such failure requires, despite the use
of diligent efforts, a period in excess of thirty (30) days, then such thirty
(30) day period shall be extended for so long as Landlord pursues the cure
thereof with reasonable diligence) shall constitute a default under this Lease
by Landlord.  Provided that Tenant receives written notice of the name and
address of any lender to Landlord that is the beneficiary of a deed of trust
that encumbers the Premises, Tenant hereby covenants to give such lender written
notice of any failure by Landlord to observe and perform any provision of this
Lease to be observed and performed by Landlord, which notice shall be given
simultaneously with, and in the same manner as, the notice of such failure given
by Tenant to Landlord. Furthermore, Tenant hereby covenants to accept the cure
of such failure by such lender provided that such cure occurs within thirty (30)
days after receipt of such notice by such lender; provided further, however,
that if such cure requires,despite the use of diligent efforts, a period in
excess of thirty (30) days, then such thirty (30) day period shall be extended
for so long as such lender pursues the cure thereof with reasonable diligence.
Notwithstanding the foregoing, such lender shall in no case be obligated to cure
any failure by Landlord.  Upon the occurrence of a default by Landlord, Tenant
may pursue any remedy provided under this Lease or by law, subject to any
provisions of this Lease limiting Tenant's remedies (including, without
limitation, the provisions of Section 15.1).  Without limiting the remedies
                              -------------
otherwise conferred upon Tenant, if Landlord fails to perform a repair which it
is obligated to perform under this Lease and such failure continues for fifteen
(15) days after notice by Tenant to Landlord (provided, however, that if the
cure of such failure requires, despite the use of diligent efforts, a period in
excess of fifteen (15) days, then such fifteen (15) day period shall be extended
for so long as Landlord pursues the cure thereof with reasonable diligence),
then Tenant shall have the right (but not the obligation) to perform such repair
on Landlord's behalf and any reasonable amount which Tenant spends in performing
such repair shall be repaid by Landlord within thirty (30) days after delivery
to Landlord of a copy of the invoice for such repair together with proof of
payment thereof.

  12.5   Attorneys' Fees.  If legal action is necessary in order to enforce or
         ---------------
interpret this Lease, the prevailing party will be entitled to reasonable
attorneys' fees, costs and disbursements in addition to any other relief to
which such party is entitled.

  12.6   Waiver.  No covenant, term or conditionor the breach thereof will be
         ------
deemed waived, except by written consent of the party against whom the waiver is
claimed and any waiver of the breach of any covenant, term or condition will not
be deemed to be a waiver of any preceding or succeeding breach of the same or
any other covenant, term or condition.  Acceptance by Landlord of any
performance by Tenant after the time the same was due will not constitute a
waiver by Landlord of the breach or default of any covenant, term or condition
unless otherwise expressly agreed to by Landlord in writing.

                               Part Two-Page 23
<PAGE>

  12.7   Force Majeure.  Whenever a period of time is herein prescribed for the
         -------------
taking of any action by either Landlord or Tenant (other than the payment
obligations of Landlord or Tenant hereunder), the performing party shall not be
liable or responsible for, and there shall be excluded from the computation of
such period of time, any delays due to strikes, riots, acts of God, shortages of
labor or materials, war, governmental laws, regulations or restrictions, or any
act, omission, delay, or neglect of the other party or any employees or agents
of the other party, or any other cause whatsoever beyond the control of the
performing party.

13.      ESTOPPEL CERTIFICATES
         ---------------------

  13.1   Acknowledgment of Commencement Date.  Upon tender of possession of the
         -----------------------------------
Premises to the Tenant and as often thereafter as may be reasonably  requested
by Landlord, Tenant will, within twenty (20) days after receipt of a request
from Landlord, execute, acknowledge and deliver to Landlord a statement which
will (a) set forththe actual Commencement Date and Expiration Date of the Term,
and (b) contain acknowledgments that Tenant has accepted the Premises and that
the Premises and Building are satisfactory in all respects, if such statements
are accurate.

  13.2   Certificates.  Tenant or Landlord will, within twenty (20) days after
         ------------
receipt of a request from the other or any mortgagee of either party, execute,
acknowledge and deliver to the requesting party or such mortgagee either a
statement in writing or three party agreement among Landlord, Tenant and such
mortgagee (a) certifying that this Lease is unmodified and in full force and
effect (or, if modified, stating the nature of such modification and certifying
that this Lease, as so modified, is in full force and effect) and the date to
which Base Rent and other charges are paid in advance, if any; (b) acknowledging
that there are not, to the requesting party's knowledge, any uncured defaults on
the part of the requesting party under this Lease, or specifying such defaults
if any are claimed, and (c) specifying any further information and agreeing to
such notice provisions and other matters reasonably requested by the requesting
party or such mortgagee. Any such statement may be conclusively relied upon by a
prospective purchaser, mortgagee, assignee or sublessee of the Premises. Failure
to deliver such statement within twenty (20) days will constitute a default
under this Lease.

  13.3   Financial Statements.  Unless Tenant is a corporation for which
         --------------------
publicly available financial information is available (in which case the
provisions of this Section 13.3 shall not beapplicable), Landlord will have the
                   ------------
right to request financial statements from Tenant for purposes of selling,
financing or refinancing the Building.  Tenant will, within ten (10) days after
receipt of a request from Landlord setting forth the purposes for which such
financial statement will be used, deliver to Landlord a current financial
statement certified by Tenant's chief financial officer to be true and correct
and to fairly express Tenant's current financial condition.  All such financial
statements will be received by Landlord in confidence and used only for the
purpose set forth in the request.

14.      SUBORDINATION AND ATTORNMENT
         ----------------------------

  14.1   Lease Subordinate.  This Lease is subject and subordinate to, in
         -----------------
addition to matters

                               Part Two-Page 24
<PAGE>

currently of record: (a) all applicable present and future laws, rules,
regulations, ordinances or requirements of any governmental authority having
jurisdiction over the Project, (b) restrictive covenants affecting the Project,
as same may be amended; and (c) all utility easements and agreements, now or
hereafter created for the benefit of the Project.

  14.2 Subordination.   Upon demand, Tenant shall execute, acknowledge, and
       -------------
deliver to Landlord and any proposed mortgagee of the Building a Subordination,
Non-Disturbance and Attornment Agreement in the form of Exhibit E attached
                                                        ---------
hereto and made a part hereof, with such reasonable and customary changes
thereto as may be requested by such mortgagee.

15.    LANDLORD'S INTEREST
       -------------------

  15.1 Liability of Landlord.  If Landlord defaults under the provisions of
       ---------------------
this Lease and, if as a consequence of such default, Tenant recovers a money
judgment against Landlord, Landlord's liability under such judgment shall not
exceed the right, title and interest of Landlord in the Project. Any lien on the
Project obtained to enforce such judgment and levy of execution thereon shall be
subject and subordinate to any mortgage encumbering the Project in accordance
with the terms of any applicable Subordination, Non-Disturbance and Attornment
Agreement executed by Tenant pursuant to Section 14.2 above.  In no event will
Tenant have the right to levy execution against any property of Landlord's
partners, members, venturers, trustees, and ancillary trustees.

  15.2 Sale of Project.  The term "Landlord" will mean only the owner at the
       ---------------
time in question of the fee title or a tenant's interest in a ground lease of
the Project, provided that the successor to Landlord assumes the obligations of
Landlord under this Lease.  The obligations contained in this Lease to be
performed by Landlord will be binding on Landlord and Landlord's successors and
assigns only  as to their respective periods of ownership.  In the event of a
sale of the Project or assignment of this Lease by Landlord, the purchaser of
the Project or the assignee of this Lease, as the case may be, shall be deemed
to have assumed the obligations of Landlord hereunder during its period of
ownership.

16.    NOTICES
       -------

       Wherever in this Lease it is required or permitted that a request, notice
or demand begiven or served or consent be obtained by either party to, on, or
from the other, such request, notice, demand, or consent must be in writing and
(a) personally delivered, or (b) mailed by certified or registered United States
mail, postage prepaid, or (c) sent by Federal Express Corporation or other
nationally recognized overnight carrier for next day delivery, to the addresses
of the parties specified in the Basic Lease Provisions. Any notice which is
mailed shall be deemed to have been given on the date of receipt thereof, and
any notice sent by overnight courier will be deemed to have been given on the
regular business day next following the date of deposit of such notice in a
depository of the overnight courier. Either party may change such address by
notice to the other. Base Rent and other charges will be paid to Landlord at
Landlord's address as set forth in the Basic Lease Provisions, or as changed
pursuant to a notice delivered to Tenant in the manner specified above.

17.    BROKERS
       -------

                               Part Two-Page 25
<PAGE>

      Each of Landlord and Tenant represents and warrants that it has had no
dealings with any broker or agent in connection with the negotiation or
execution of this Lease other than the Brokers set forth in Paragraph 10 of the
Basic Lease Provisions.  Tenant shall be responsible for the fees of C B Richard
Ellis and Landlord shall be responsible for the fees of Means Knaus.

18.      INDEMNITIES AND WAIVERS
         -----------------------

  18.1   Indemnities by Tenant.  To the fullest extent permitted by law, and
         ---------------------
except to the extent caused by the willful or negligent acts of anyLandlord
Party, Tenant will, at Tenant's sole cost and expense, Indemnify Landlord
Parties against all Claims arising from (a) any Personal Injury, Bodily Injury
or Property Damage whatsoever occurring in or at the Premises, except for such
Claims asserted by an employee of a Landlord Party arising out of and in the
course of employment of such employee; (b) all Claims arising from any Bodily
Injury to an employee of a Tenant Party arising out of and in the course of
employment of the employee and occurring anywhere in the Project; (c) any liens
or encumbrances arising out of any work performed or materials furnished by or
for Tenant; (d) commissions or other compensation or charges claimed by any real
estate broker or agent with respect to this Lease by, through, or under Tenant
(unless specifically the obligation of Landlord under Section 17); or (e) the
default by Tenant under this Lease.

  18.2   Indemnities by Landlord.  To the fullest extent permitted by law (but
         -----------------------
subject to the limitations on Landlord's liability set forth in Section 15.1),
                                                                -------------
and except to the extent caused by the willful or negligent acts of any Tenant
Party, Landlord will, at Landlord's sole cost and expense, Indemnify Tenant
Parties against all Claims arising from (a) any Personal Injury, Bodily Injury
or Property Damage whatsoever occurring in the Common Areas, except for such
Claims asserted by an employee of a Tenant Party arising out of and in the
course of employment of such employee; (b) any Bodily Injury to an employee of a
Landlord Party arising out of and in the course of employment of the employee
and occurring anywhere in the Project; (c) any liens or encumbrances against any
Tenant Party or itsproperty arising out of any work performed or materials
furnished by or for Landlord; (d) commissions or other compensation or charges
claimed by any real estate broker or agent with respect to this Lease by,
through, or under Landlord (unless specifically the obligation of Tenant under
Section 17); or (e) the default by Landlord under this Lease.

  18.3   Waivers by Tenant.  Tenant, on behalf of all Tenant Parties, waives all
         -----------------
claims against Landlord Parties arising from the following: (a) any Personal
Injury, Bodily Injury, or Property Damage to any Tenant Party resulting from
interruption or stoppage of utility services (subject to Tenant's rights under
Section 5.4) or resulting from failure of Landlord to provide adequate building
-----------
security, or caused by the other lessees of the Project, parties not occupying
space in the Project, occupants of property adjacent to the Project, or the
public or by the construction of any private, public, or quasi-public work
occurring either in the Premises or elsewhere in the Project; or (b) any Bodily
Injury to an employee of a Tenant Party arising out of and in the course of
employment of the employee and occurring anywhere in the Project.

  18.4   Waivers by Landlord.  Landlord, on behalf of all Landlord Parties,
         -------------------
waives all claims

                               Part Two-Page 26
<PAGE>

against Tenant Parties arising from the following: (a) any Personal Injury,
Bodily Injury, or Property Damage to any Landlord Party resulting from
interruption or stoppage of utility services or caused by lessees of the Project
other than Tenant, parties not occupying space in the Project, occupants of
property adjacent to the Project, or the public or by the construction ofany
private, public or quasi-public work occurring either in the Premises or
elsewhere in the Project; or (b) Bodily Injury to an employee of a Landlord
Party arising out of and in the course of employment of the employee and
occurring anywhere in the Project.

  18.5   Definitions.  For purposes of the foregoing provisions of this Article
         -----------                                                    -------
18:  (a) the term "Tenant Parties" means Tenant, and Tenant's officers,
---
directors, members, partners, agents, employees, sublessees, licensees, invitees
and independent contractors, and all persons and entities claiming through any
of these persons or entities; (b) the term "Landlord Parties" means Landlord and
the partners, venturers, trustees and ancillary trustees of Landlord and the
respective officers, directors, shareholders, members, parents, subsidiaries and
any other affiliated entities, personal representatives, executors, heirs,
assigns, licensees, invitees, beneficiaries, agents, servants, employees and
independent contractors of these persons or entities; (c) the term "Indemnify"
means indemnify, defend (with counsel reasonably acceptable to the indemnified
party) and hold free and harmless from and against; (d) the term "Claims" means
all liabilities, claims, damages (including consequential damages to the extent
not excluded by the provisions of the last sentence of Section 21.18), losses,
penalties, litigation, demands, causes of action (whether in tort or contract,
in law or at equity or otherwise), suits, proceedings, judgments,
disbursements, charges, assessments, and expenses (including attorneys' and
experts' fees and expenses and expenses incurred in investigating, defending, or
prosecuting any litigation, claim, or proceeding); (e) the term"Waives" means
that the waiving party  waives and knowingly and voluntarily assumes the risk
of; and (f) the terms "Bodily Injury", "Personal Injury" and "Property Damage"
will have the same meanings as in the form of commercial general insurance
policy issued by Insurance Services Office, Inc. most recently prior to the date
of the injury or loss in question.

  18.6   Scope of Waivers.  The  waivers contained in Section 18.3 and Section
         ----------------                             ------------
18.4 will apply regardless of the active or passive negligence or sole, joint,
----
concurrent, or comparative negligence of any of the Landlord Parties or Tenant
Parties, as the case may be.

  18.7   Obligations Independent of Insurance. The indemnification provided in
         ------------------------------------
Section 18.1 may not be construed or interpreted as in any way restricting,
------------
limiting or modifying Tenant's insurance or other obligations under this Lease,
and the provisions of Section 18.1 are independent of Tenant's insurance and
                      ------------
other obligations.  Tenant's compliance with the insurance requirements and
other obligations under this Lease does not in any way restrict, limit or modify
Tenant's indemnification obligations under this Lease.  Conversely, The
indemnification provided in Section 18.2 may not be construed or interpreted as
                            ------------
in any way restricting, limiting or modifying Landlord's insurance or other
obligations under this Lease, and the provisions of Section 18.2 are independent
                                                    ------------
of Landlord's insurance and other obligations.  Landlord's compliance with the
insurance requirements and other obligations

                               Part Two-Page 27
<PAGE>

under this Lease does not in any way restrict, limit or modify Landlord's
indemnification obligations under this Lease.

  18.8   Survival.  The provisions of this Article 18 will survive the
         --------                          ----------
expiration or earlier termination of this Lease until all claims against
Landlord Parties involving any of the indemnified or waived matters are fully
and finally barred by the applicable statutes of limitations.

  18.9   Duty to Defend.  The duty of an indemnifying party to defend is
         --------------
separate and independent of such party's duty to Indemnify. The duty of an
indemnifying party to defend includes Claims for which the indemnified party may
be liable without fault or may be strictly liable.  The duty of an indemnifying
party to defend applies regardless of whether the issues of negligence,
liability, fault, default or other obligation on the part of the indemnifying
party have been determined.  The duty of an indemnifying party to defend applies
immediately, regardless of whether the indemnified party has paid any sums or
incurred any detriment arising out of or relating, directly or indirectly, to
any Claims.  It is the express intention of Landlord and Tenant that the
indemnified party  will be entitled to obtain summary adjudication regarding the
indemnifying party's duty to defend the indemnified party at any stage of any
Claim within the scope of this Article 18.
                               ----------

19.      PARKING
         -------

  19.1   Garage.  Notwithstanding anything set forth in this Lease to the
         ------
contrary, the existing parking garage in the Building shall be for the exclusive
use of Tenant and the other tenants and occupants of the Building and its and
their employees, customers, visitors and invitees.  No part of such existing
parking garage shall be designated or reserved for use by any tenants or
occupants, or their employees, customers, visitors and invitees, of any
improvements to be built on the Excess Land.  Tenant's use of the parking garage
shall be subject to such terms, conditions and regulations as are from time to
time applicable to the patrons of the parking garage, but shall be without
charge to Tenant.

20.      HAZARDOUS SUBSTANCES; REPRESENTATIONS
         -------------------------------------

  20.1   Tenant's Operations.  The term "Hazardous Substances", as used in this
         -------------------
Lease will mean pollutants, contaminants, toxic or hazardous wastes, or any
other substances, the removal of which is required or the use of which is
regulated, restricted, prohibited or penalized by any Environmental Law.  Tenant
hereby agrees that (i) no activity will be conducted on the Premises that will
produce any Hazardous Substances, except for such activities that are part of
the ordinary course of Tenant's business activities ("Permitted Activities")
provided the Permitted Activities are conducted in accordance with all
Environmental Laws; (ii) the Premises will not be used in any manner for the
storage of any Hazardous Substances except for any temporary storage of such
materials that are used in the ordinary course of Tenant's business ("Permitted
Materials"), provided such Permitted Materials are properly stored in a manner
and location meeting all Environmental Laws; (iii)Tenant will not permit any
Hazardous Substances to be brought onto the Premises, except for the Permitted
Materials, and if so brought or found thereon, the same shall be immediately
removed, with proper disposal, and all required cleanup

                               Part Two-Page 28
<PAGE>

procedures shall be diligently undertaken pursuant to all Environmental Laws. If
any Hazardous Substance is discovered outside the Premises and such Hazardous
Substance was brought into the Building or parking areas or any other portion of
the Project by Tenant or any of Tenant Parties (as defined in Section 18.5),
Tenant, at Tenant's sole cost and expense, will immediately take such action as
is necessary to detain the spread of and remove the Hazardous Substance to the
satisfaction of Landlord.

21.      INTERPRETATIVE
         --------------

  21.1   Captions.   The captions of the Articles and Sections of this Lease are
         --------
for convenience only and will not affect the interpretation or construction of
any provision of this Lease.

  21.2   Section Numbers.  All references to section numbers contained in the
         ---------------
Basic Lease Provisions, the General Lease Provisions or Exhibit C, if any, are
                                                        ---------
to sections in the General Lease Provisions, unless expressly provided to the
contrary.

  21.3  Attachments.  Exhibits, addenda, schedules and riders attached hereto
        -----------
and listed in the Basic Lease Provisions (and no other exhibits, addendums,
schedules and riders) are deemed by attachment to constitute part of this Lease
and are incorporated into this Lease.

  21.4   Number, Gender, Defined Terms.  The words "Landlord" and "Tenant", as
         -----------------------------
used in this Lease, will include the plural as well as the singular.  Words used
in the neuter gender include the masculine and feminine and words in the
masculine or feminine gender include the other and the neuter.  If more than one
person or entity constitutes Tenant, the obligations under this Lease imposed
upon Tenant will be joint and several.

  21.5  Entire Agreement.   This Lease, including any exhibits and attachments
        ----------------
hereto listed in the Basic Lease Provisions, constitutes the entire agreement
between Landlord and Tenant relative to the Premises.  Landlord and Tenant agree
hereby that all prior or contemporaneous oral and written agreements between and
among themselves or their agents, including any leasing agent, and
representatives relative to the leasing of the Premises are merged in or revoked
by this Lease.  Notwithstanding the foregoing, the representations and
warranties of Tenant, as seller, and Landlord, as purchaser, under the Purchase
and Sale Agreement of even date herewith are not merged or revoked and shall
continue to be applicable.

  21.6   Amendment.  This Lease and the exhibits and attachments may be altered,
         ---------
amended or revoked only by an instrument in writing signed by both Landlord and
Tenant.

  21.7   Severability.   If any term or provision of this Lease is, to any
         ------------
extent, determined by a court of competent jurisdiction to be invalid or
unenforceable, the remainder of this Lease will not be affected thereby, and
each remaining termand provision of this Lease will be valid and be enforceable
to the fullest extent permitted by law.

  21.8   Time of Essence.  Time is of the essence of this Lease and each and
         ---------------
every provision of this Lease.

  21.9   Best Efforts.  Whenever in this Lease there is imposed upon either
         ------------
party the obligation to use the best efforts of a party or reasonable

                               Part Two-Page 29
<PAGE>

efforts or diligence, such party will be required to exert such efforts or
diligence only to the extent the same are economically feasible and will not
impose upon such party extraordinary financial or other burdens.

  21.10  Binding Effect.  Subject to any provisions of this Lease restricting
         --------------
assignment by Tenant and releasing Landlord upon sale of the Building, all of
the provisions of this Lease will bind and inure to the benefit of the parties
to this Lease and their respective heirs, legal representatives, successors and
assigns.

  21.11  Subtenancies.  The voluntary or other surrender of this Lease by
         ------------
Tenant, or a mutual cancellation thereof, will not work a merger of estates and
will, at the option of Landlord, operate as an assignment to Landlord of any or
all subleases or subtenancies.

  21.12  No Reservation.   Submission by Landlord of this instrument to Tenant
         --------------
for examination or signature does not constitute a reservation of or option for
lease.  This Lease will be effective only upon execution and delivery by both
Landlord and Tenant.

  21.13  Consents.  If Tenant requests Landlord's consent under any provision of
         --------
this Lease and Landlord fails or refuses to give such consent, Tenant's sole
remedy will be an action for specific performance or injunction.

  21.14  Choice of Law.  This Lease will be construed under, governed by and
         -------------
enforced in accordance with the laws of the State of Texas.

  21.15.  Non-Merger.  There shall be no merger of this Lease with any ground
          ----------
leasehold interest or the fee estate in the Project or any part thereof by
reason of the fact that the same person may acquire or hold, directly or
indirectly, this Lease or any interest in this Lease as well as any ground
leasehold interest or fee estate in the Project or any interest in such fee
estate.

  21.16.  Representations of Landlord.  Except as expressly set forth in this
          ---------------------------
Lease, neither Landlord nor Landlord's agents or brokers have made any
representations or promises with respect to the Premises, the Building, or any
other part of the Project.  Unless otherwise expressly provided in this Lease,
to the extent permitted by applicable law, Landlord and Tenant expressly
disclaim any implied warranty that the Premises are suitable for Tenant's
intended commercial purpose, it being acknowledged that Landlord has purchased
the Project from Tenant on even date herewith.

  21.17.  Jointly Prepared Document.  Should any provision of this Lease require
          -------------------------
judicial interpretation, Landlord and Tenant hereby agree and stipulate that the
court interpreting or considering same shall not apply the presumptionthat the
terms hereof shall be more strictly construed against a party by reason of any
rule or conclusion that a document should be construed more strictly against the
party who itself or through its agents prepared the same, it being agreed that
all parties hereto have participated in the preparation of this Lease and that
each party had full opportunity to consult legal counsel of its choice before
the execution of this Lease.

  21.18.  Waiver of Trial by Jury.  Landlord and Tenant hereby waive trial by
          -----------------------
jury in any action, proceeding or counterclaim brought by either party hereto in
respect of any matter arising out of or in any way connected with this Lease or
Tenant's use or occupancy of the  Premises.

                               Part Two-Page 30
<PAGE>

Under no circumstances whatsoever shall Landlord or Tenant be liable to the
other for such other party's own consequential damages or special damages.

  21.19  Independent Covenants.  The obligations of Tenant to pay rent hereunder
         ---------------------
is not dependent upon the condition of the Premises or the performance by
Landlord of its obligations hereunder, and, except as otherwise expressly
provided herein, (a) Tenant shall continue to pay rent, without abatement,
setoff, or deduction notwithstanding any claim that Landlord has breached its
obligations hereunder; and (b) Tenant waives and relinquishes all rights which
Tenant may have (including specifically, without limitation, all rights under
Section 91.004 of the Texas Property Code) to claim any lien against any
property of Landlord or to withhold, deduct or offset rent hereunder.

  21.20  Execution on Behalf of Tenant. Theperson executing this Lease on behalf
         -----------------------------
of Tenant, by execution hereof, represents to Landlord that he or she has the
authority to bind such Tenant to the terms of this Lease.

  21.21  Execution on Behalf of Landlord. The person executing this Lease on
         -------------------------------
behalf of Landlord, by execution hereof, represents to Tenant that he or she has
the authority to bind such Landlord to the terms of this Lease.

  21.22  Quiet Enjoyment.  Landlord represents and warrants that it has full
         ---------------
right and authority to enter into this Lease and that Tenant, so long as Tenant
is paying the rent due under this Lease as same becomes due and is performing
its other covenants and agreements set forth herein, shall peaceably and quietly
have, hold and enjoy the Premises for the Term, subject  to the terms and
provisions of this Lease.

  21.23  Conflict with Rules and Regulations. In the event  of any conflict
         -----------------------------------
between the terms of this Lease (including the exhibits hereto other than the
exhibit containing the Rules and Regulations) and the Rules and Regulations, the
terms of this  Lease shall govern.

                               Part Two-Page 31
<PAGE>

                                   EXHIBIT A

                               LEGAL DESCRIPTION

     Being 14.3048 ACRES (623,119 square feet) of land all of Restricted Reserve
"I" (Restricted for Non-Residential use), in Block Six (6) of Partial Replat of
Enclave, a subdivision in Harris County, Texas according to the map or plat
thereof recorded in Volume 328, Page 13 of the Map Records of Harris County,
Texas.

                              Exhibit A - page 1

<PAGE>

                                   EXHIBIT B

                                  FLOOR PLANS

                                 See Attached

                               Exhibit B, page 1
<PAGE>

                                 [FLOOR PLAN]
<PAGE>

                                 [FLOOR PLAN]
<PAGE>

                                 [FLOOR PLAN]
<PAGE>

                                 [FLOOR PLAN]
<PAGE>

                                 [FLOOR PLAN]
<PAGE>

                                   EXHIBIT C

                          OPERATING COST COMPUTATION

     1.   Operating Cost Exclusions.  The following costs are notwithstanding
          -------------------------
anything to the contrary set forth in this Lease (including Section 2 of this
Exhibit C), excluded from the computation of Operating Costs:

          (a)  leasing commissions, attorneys' fees, costs and disbursement and
other expenses incurred in connection with leasing, renovating or improving
space for tenants or prospective tenants of the Project;

          (b)  costs (including permit, license and inspection fees) incurred in
renovating or otherwise improving or decorating, painting or redecorating space
for tenants or vacant space;

          (c)  Landlord's costs of any services sold to tenants for which
Landlord is entitled to be reimbursed by such tenants as an additional charge or
rental over and above the Base Rent and Operating Costs payable under the lease
with such tenant or other occupant;

          (d)  any depreciation and amortization on the Project except as
expressly permitted herein;

          (e)  costs incurred due to violation by Landlord of any of the
terms and conditions of this Lease or any other lease relating to the Project;

          (f)  interest on debt or amortization payments on any mortgages or
deeds of trust or any other debt for borrowed money;

          (g)  all items and services for which Tenant reimburses Landlord
outside of Operating Costs or pays third persons or which Landlord provides
selectively to one or more tenants or occupants of the Project (other than
Tenant) without reimbursement;

          (h)  advertising and promotional expenditures;

          (i)  repairs or other work occasioned by fire, windstorm or other
casualty, or by condemnation, or other work paid for through insurance or
condemnation proceeds;

          (j)  repairs resulting from any defect in the original design or
construction of the Project;

          (k)  amortization of the costs of improvements to the Project which
are capital in nature, except to the extent set forth in Section 2(p) of this
                                                         ------------
Exhibit C;
----------

          (l)  federal, state and local income taxes, inheritance taxes, estate
taxes, gift taxes and franchise taxes paid by Landlord;

          (m)  rents paid under any ground lease in respect of the Land or the
Building;

          (n)  any interest, fines, penalties and related expenses (including
attorneys' fees)

                               Exhibit C, page 1
<PAGE>

incurred by Landlord as a result of (i) Landlord's violation of any governmental
rule, statute or authority (including specifically, without limitation, the
failure of Landlord to pay timely real estate taxes or assessments in respect of
the Project), (ii) default by Landlord under any mortgage encumbering the
Project, or (iii) default by Landlord under this Lease;

          (o)  losses of rent, bad debts or any damages or settlements paid to
any other tenant, prospective tenant or occupant of the Building; or

          (p)  costs representing an amount paid to an affiliate of Landlord
which is in excess of the amount which would have been paid in the absence of
such relationship;

          (q)  costs incurred to test, survey, clean up, contain, abate, remove
or otherwise remedy any Hazardous Substances from the Project placed thereon by
Landlord.

     2.   Operating Cost Examples. The following are, without limitation,
          -----------------------
examples of costs included within the computation of Operating Costs:

          (a)  garbage and waste disposal;

          (b)  janitorial service and window cleaning for the Project (including
materials, supplies, light bulbs and ballasts standard to the Building,
equipment and tools therefor and rental and depreciation costs related to any of
the foregoing) or contracts with third parties to provide same;

          (c)  security;

          (d)  insurance premiums (including, without limitation, property,
rental value, liability and any other types of insurance carried by Landlord
with respect to the Project, the costs of which may include an allocation of a
portion of the premium of a blanket insurance policy maintained by Landlord);

          (e)  business or excise taxes payable on account of Landlord's
ownership or operation of the Project (including, without limitation, any state
tax imposed upon Landlord as a substitute in whole or in part for, or in
addition to, real property taxes assessed against the Premises as of the date of
this Lease);

          (f)  real estate taxes, assessments, excises, and any other
governmental levies and charges of every kind and nature whatsoever, general and
special, extraordinary and ordinary, foreseen and unforeseen, which may during
the Term be levied or assessed against, or arising in connection with the use,
occupancy, operation or possession of, the Project, or any part thereof, or
substituted, in whole or in part, for a real estate tax, assessment, excise or
governmental charge or levy previously in existence, by any authority having the
direct or indirect power to tax, including interest on installment payments and
all costs and fees (including attorneys' fees) incurred by Landlord in
contesting or negotiating with taxing authorities as to same; provided, however,
that Landlord will pay all such taxes and assessments over the longest

                               Exhibit C, page 2
<PAGE>

period of time permitted by the applicable taxing authority;

          (g)  water and sewer charges and any add-ons;

          (h)  operation, maintenance, and repair (to include replacement of
components) of the Project, including but not limited to all floor, wall and
window coverings and personal property in the Common Areas, Building systems
such as heat, ventilation and air conditioning system, elevators, escalators,
and all other mechanical or electrical systems serving the Building and the
Common Areas and Service Areas and service agreements for all such systems and
equipment (to the extent any of such costs constitute capital expenditures, then
the last sentence of Subsection 2(p) below shall apply);

          (i)  charges for any easement maintained for the benefit of the
Project;

          (j)  license, permit and inspection fees;

          (k)  compliance with any fire safety or other governmental rules,
regulations, laws, statutes, ordinances or requirements imposed by any
governmental authority or insurance company with respect to the Project during
the Term hereof (to the extent any of such costs constitute capital
expenditures, then the last sentence of Subsection 2(p) below shall apply);

          (l)  wages, salaries, employee benefits and taxes (or an allocation of
the foregoing) for personnel working full or part time in connection with the
operation, maintenance and management of the Project;

          (m)  accounting and legal services (but excluding legal services in
connection with negotiations and disputes with specific tenants unless the
matter involved affects all tenants of the Project);

          (n)  administrative and management fees for the Project and Landlord's
overhead expenses directly attributable to Project management;

          (o)  indoor or outdoor landscaping;

          (p)  depreciation (or amortization) of Required Capital Improvements
and Cost Savings Improvements. "Required Capital Improvements" will mean capital
improvements or replacements made in or to the Building in order to conform to
any future law, ordinance, rule, regulation or order of any governmental
authority not existing as of the date of this Lease having jurisdiction over the
project, including, without limitations, The Disabilities Acts. "Cost Savings
Improvements" will mean any capital improvements or replacements which are
intended to reduce, stabilize or limit increases in Operating Costs. The cost of
Required Capital Improvements, Cost Savings Improvements and depreciable (or
amortizable) maintenance and repair items (e.g., painting of Common Areas,
replacement of carpet in elevator lobbies), will be amortized over the useful
life of the applicable item in accordance with generally accepted accounting
principles.

                               Exhibit C, page 3
<PAGE>

          (q)  expenses and fees (including attorneys' fees) incurred contesting
of the validity or applicability of any governmental enactments which may affect
Operating Costs.

          (r)  Costs incurred by Landlord for (i) electricity utilized in
connection with the operation, maintenance, and use of the Project, and (ii)
sales, use, excise and other taxes assessed by governmental authorities on
electricity.

          (s)  all assessments owed by Landlord pursuant to the Amended and
Restated Declaration of Covenants, Conditions and Restrictions (Including the
Fifth Amendment) for Enclave (the "Declaration"), including, but not limited to,
the Basic Charge (as such term is defined in the Declaration).

     3.   Landlord will credit against Operations Costs any refunds received as
a result of tax contests, after deduction for Landlord's costs in connection
with same.

     4.   The foregoing provisions of this Exhibit C will not be deemed to
                                           ---------
require Landlord to furnish or cause to be furnished any service or facility not
otherwise required to be furnished by Landlord pursuant to the provisions of
this Lease, although Landlord, in Landlord's absolute discretion, may choose to
do so from time to time.

                               Exhibit C, page 4
<PAGE>

                                   EXHIBIT D

                         BUILDING RULES AND REGULATIONS
                         ------------------------------

     The following rules and regulations shall apply to the Premises, the
Building, the parking garage associated therewith, and the appurtenances
thereto:

1.   Sidewalks, doorways, vestibules, halls, stairways, and other similar areas
     shall not be obstructed by tenants or used by any tenant for purposes other
     than ingress and egress to and from their respective leased premises and
     for going from one to another part of the Building.

2.   Plumbing, fixtures and appliances shall be used only for the purposes for
     which designed, and no sweepings, rubbish, rags or other unsuitable
     material shall be thrown or deposited therein.  Damage resulting to any
     such fixtures or appliances from misuse by a tenant or its agents,
     employees or invitees, shall be paid by such tenant.

3.   No signs, advertisements or notices shall be painted or affixed on or to
     any windows or doors or other part of the Building without the prior
     written consent of Landlord.  No nails, hooks or screws shall be driven or
     inserted in any part of the Building except by Building maintenance
     personnel.  No curtains or other window treatments shall be placed between
     the glass and the Building standard window treatments.

4.   Landlord shall provide and maintain an alphabetical directory for all
     tenants in the main lobby of the Building.

5.   Landlord shall provide all door locks in each tenant's leased premises, at
     the cost of such tenant, and no tenant shall place any additional door
     locks in its leased premises without Landlord's prior written consent.
     Landlord shall furnish to each tenant a reasonable number of keys to such
     tenant's leased premises, at such tenant's cost, and no tenant shall make a
     duplicate thereof.

6.   Movement in or out of the Building of furniture or office equipment, or
     dispatch or receipt by tenants of any bulky material, merchandise or
     materials which require use of elevators or stairways, or movement through
     the Building entrances or lobby shall be conducted under Landlord's
     supervision at such times and in such a manner as Landlord may reasonably
     require.  Each tenant assumes all risks of and shall be liable for all
     damage to articles moved and injury to persons or public engaged or not
     engaged in such movement, including equipment, property and personnel of
     Landlord if damaged or injured as a result of acts in connection with
     carrying out this service for such tenant.

                               Exhibit D, Page 1
<PAGE>

7.   Landlord may prescribe weight limitations and determine the locations for
     safes and other heavy equipment or items, which shall in all cases be
     placed in the Building so as to distribute weight in a manner acceptable to
     Landlord which may include the use of such supporting devices as Landlord
     may require.  All damages to the Building caused by the installation or
     removal of any property of a tenant, shall be repaired at the expense of
     such tenant.

8.   Corridor doors, when not in use, shall be kept closed.  Nothing shall be
     swept or thrown into the corridors, halls, elevator shafts or stairways.
     No birds or animals shall be brought into or kept in, on or about any
     tenant's leased premises.  No portion of any tenant's leased premises shall
     at any time be used or occupied as sleeping or lodging quarters.

9.   Tenant shall cooperate with Landlord's employees in keeping its leased
     premises neat and clean.  Tenants shall not employ any person for the
     purpose of such cleaning other than the Building's cleaning and maintenance
     personnel.

10.  To ensure orderly operation of the Building, no ice, mineral or other
     water, towels, newspapers, etc.  shall be delivered to any leased area
     except by persons approved by Landlord.

11.  Tenant shall not make or permit any vibration or improper, objectionable or
     unpleasant noises or odors in the Building or otherwise interfere in any
     way with other tenants or persons having business with them.

12.  No machinery of any kind (other than normal office equipment) shall be
     operated by any tenant on its leased area without Landlord's prior written
     consent, nor shall any tenant use or keep in the Building any flammable or
     explosive fluid or substance.

13.  Landlord will not be responsible for lost or stolen personal property,
     money or jewelry from tenant's leased premises or public or common areas
     regardless of whether such loss occurs when the area is locked against
     entry or not.

14.  All vehicles are to be currently licensed, parked for business purposes
     having to do with tenant's business operated in the Premises, parked within
     designated parking spaces, one vehicle to each space.  No vehicle shall be
     parked as a "billboard" vehicle in the parking lot. Any vehicle parked
     improperly may be towed away.  Tenant, tenant's agents, employees, vendors
     and customers who do not operate or park their vehicles as required shall
     subject the vehicle to being towed at the expense of the owner or driver.
     Landlord may place a "boot" on the vehicle to immobilize it and may levy a
     charge of $50.00 to remove the "boot."

                               Exhibit D, Page 2
<PAGE>

                                   EXHIBIT E

            SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT
            -------------------------------------------------------

     THIS SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT (the
"Agreement") is made and entered into this ____ day of ____________, 2000, by
 ---------
and between ___________, ___________________________a ____________ corporation
(hereinafter referred to as "Tenant"), and ___________________________________
                             ------
_____________________________________________________________, a
______________________ (hereinafter referred to as "Lender").
                                                    ------

     WHEREAS, pursuant to that certain Office Building Lease (hereinafter
referred to as the "Lease") dated _______, 2000, between __________________
                    -----
___________________________________ (hereinafter referred to as "Landlord"), as
                                                                 --------
Landlord, and Tenant, as Tenant, Landlord leased to Tenant __________ square
feet of space (hereinafter referred to as the "Premises") in an office building
                                               --------
(the "Building") located at ____ _____________________________, a legal
      --------
description of the Building and the land on which the Building is located being
set forth on Exhibit "A" attached hereto and by this reference made a part
             -----------
hereof (the Building and such land being hereinafter referred to as the
"Property"); and
 --------

     WHEREAS, Landlord has granted to Lender a security interest in and to the
Property pursuant to a certain Deed of Trust executed by Landlord in favor of
________________________ as Trustee, for the benefit of Lender, dated _________
______________, 2000, recorded or to be recorded in the public records of
_______________ County, Texas (hereinafter referred to as the "Mortgage").
                                                               --------

     WHEREAS, Tenant has been requested by Lender and by Landlord to enter into
this Agreement, and Tenant is willing to do so as hereinafter set forth;

     WHEREAS, Lender and Tenant desire to confirm their understanding with
respect to the Lease and the Mortgage;

     NOW, THEREFORE, for and in consideration of the premises and the mutual
covenants and promises contained herein, and other good and valuable
consideration, Lender and Tenant hereby agree as follows:

     1.   Subordination.  The Lease and the rights of Tenant thereunder are
          -------------
hereby subordinated and shall be and remain subordinated to the Mortgage and the
lien thereof, and to any and all renewals, modifications, consolidations,
spreaders and extensions thereof.  Nothing contained herein shall be deemed or
construed as limiting or restricting the

                               Exhibit E, Page 1
<PAGE>

enforcement by Lender of any of the terms, covenants, provisions or remedies
contained in the Mortgage, to the extent not inconsistent with the Lease.

     2.   Non-Disturbance.  For purposes hereof, the term "Remedial Action"
          ---------------                                  ---------------
shall mean the transfer of title to the Property by foreclosure, deed in lieu of
foreclosure or otherwise in the exercise of Lender's rights under the Mortgage,
and the term "Purchaser" shall mean Lender or any other party who acquires title
              ---------
to the Property pursuant to a Remedial Action.  It is hereby agreed that in the
event of a Remedial Action, and so long as no default by Tenant then exists
under the Lease beyond any applicable cure period, then the Lease and Tenant's
right to possession of the Premises thereunder  shall not be terminated, nor
shall any of Tenant's other rights under the Lease be affected on account of
such Remedial Action, and Tenant's possession of the Premises and Tenant's
rights and privileges under the Lease, or under extensions or renewals thereof,
shall not be diminished or interfered with by Purchaser.  Tenant's occupancy of
the Premises shall not be disturbed by Purchaser for any reason whatsoever
during the term of the Lease or any extension or renewal thereof, except as
would be permitted for Landlord to do so, provided that no default by Tenant
exists under the Lease beyond any applicable cure period.

     3.   Joinder of Tenant as Party Defendant.  So long as Tenant is not in
          ------------------------------------
default beyond any applicable cure period in the payment or performance of any
of the terms, covenants or conditions of the Lease on Tenant's part to be
performed, Lender will not join Tenant as a party defendant in any foreclosure
action or other proceeding under the Mortgage or otherwise.

     4.   Attornment; Obligations of Lender.
          ---------------------------------

          (a)  If  the interests of Landlord in the Property shall become owned
by a Purchaser, then: (i) Tenant shall be directly bound to Purchaser as
landlord under all the terms, covenants and conditions of the Lease, subject to
the terms of this Agreement, for the balance of the term of the Lease and for
any extensions or renewals thereof which may be duly exercised by Tenant, with
the same force and effect as if Purchaser were the Landlord under the Lease; and
(ii) Tenant will attorn to Purchaser as its landlord, said attornment to be
effective and self-operative (without the execution of any further instruments)
immediately upon Purchaser succeeding to the interest of the Landlord under the
Lease; provided, however, that Tenant shall have received written notice from
Purchaser that it has succeeded to the interest of the Landlord under the Lease.

          (b)  The respective rights and obligations of Tenant and Purchaser
upon such attornment, to the extent of the then remaining balance of the term of
the Lease and any such extensions and renewals thereof, shall be and are the
same as now set forth in the Lease, and Tenant shall have the same remedies
against Purchaser for the breach of any agreement contained in the Lease that
Tenant would have under the Lease against Landlord if Purchaser

                               Exhibit E, Page 2
<PAGE>

had not succeeded to the interest of Landlord; provided, however, that,
notwithstanding anything to the contrary contained herein, Purchaser shall not:

               (i)   be liable for any damages or other relief or be subject to
     any offsets or defenses of any kind in any case attributable to any default
     by any prior landlord under the Lease  (including, without limitation,
     Landlord), unless notice thereof has been given to Lender pursuant to
     Paragraph 7 hereof and such default has not been cured within the grace
     period, if any, provided for doing so under the Lease; provided, however,
     the foregoing shall not be construed as imposing personal liability on
     Purchaser, but Tenant shall have all of its rights and remedies pursuant to
     the Lease and at law or in equity by reason of such default if same is not
     cured within the grace period provided in the Lease;

               (ii)  be bound by any prepayment by Tenant of more than one
     month's installment of rent, unless such prepayment of rent shall have been
     approved in writing by Lender (or by any subsequent holder of the Mortgage
     of which Tenant has been notified in writing).

               (iii) be bound by any amendment to the Lease which requires the
     approval of Lender pursuant to Paragraph 6(b) below, unless written
     approval thereof has been obtained from Lender (or by any subsequent holder
     of the Mortgage of which Tenant has been notified in writing).

     5.     Assignment of Rents.  Tenant acknowledges that, in addition to the
            -------------------
Mortgage and certain other documents, the loan secured by the Mortgage will be
secured by an Assignment of Leases and Rents ("Assignment of Leases") whereby
                                               --------------------
the Lease and the rent and all other sums due thereunder have been assigned or
are to be assigned to Lender as security for such loan.  In the event that
Lender (or any person or entity to whom the Mortgage and/or Assignment of Leases
may subsequently be assigned) notifies Tenant in writing of a default under the
Mortgage or Assignment of Leases and demands that Tenant pay its rent and all
other sums due under the Lease to Lender (or such future lender), Tenant shall
honor such demand and pay its rent and all other sums due under the Lease
directly to Lender (or such future lender) or as otherwise required pursuant to
such notice.  By its execution hereof, Landlord hereby agrees that Tenant shall
have the right to honor such demand by Lender (or such future lender) without
incurring liability to Landlord.

     6.   Agreement of Tenant.  Tenant agrees not to do any of the following:
          -------------------

          (a)  prepay the rent under the Lease for more than one (1) month in
          advance;

                               Exhibit E, Page 3
<PAGE>

          (b)  enter into any agreement with Landlord to amend or modify the
Lease to reduce the rental thereunder or increase the obligations or liabilities
of Landlord, or reduce any cure periods provided to Landlord thereunder, or
terminate the Lease, without prior written consent of Lender; or

          (c)  voluntarily surrender the Premises or terminate the Lease without
          cause.

     7.   Notices Sent to Landlord/Lender Right to Cure.  In the event of a
          ---------------------------------------------
default by Landlord under the Lease, Tenant hereby agrees to give Lender the
same notice and cure period, if any, granted Landlord under the Lease before
Tenant takes action with respect to the uncured default.  Lender shall have the
right, but not the obligation, to cure any default by Landlord within the
aforementioned cure period.  Notwithstanding the foregoing provisions, however,
if the default by Landlord is of such a nature that it cannot be cured by Lender
(for example, the filing of bankruptcy by Landlord), then Tenant shall not be
obligated to give Lender such notice.  It is expressly understood and agreed
that if Tenant is not obligated to give Landlord any notice with respect to the
failure of Landlord to perform a repair obligation in the event of an emergency,
then Tenant shall not be required to give Lender notice in respect thereof prior
to commencing a cure.

     8.   Amendment.  This Agreement may not be modified or amended, except by
          ---------
a writing by Lender and Tenant or their respective successors in interest, as
applicable.  Upon satisfaction of the Mortgage, this Agreement shall become null
and void and be of no further affect.

     9.   Notices.  Whenever in this Agreement it is provided that notice be
          -------
given to or served upon either of the parties, each such notice or demand shall
be in writing, and (a) personally delivered, or (b) sent by FedEx or other
nationally recognized overnight courier for next day delivery, to the addresses
of the parties hereinafter specified.  Any notice which is sent by overnight
courier will be deemed to have been given on the regular business day next
following the date of deposit of such notice in a depository of the overnight
courier.  Either party may change this address for notice by notice to the other
party.  The addresses for notices are as follows:

     If addressed to Lender:

     With a copy to:

                              Exhibit E, Page 4
<PAGE>

     If sent to Tenant:

     With a copy to:

     10.    Effectiveness.  Notwithstanding anything herein to the contrary,
            -------------
Tenant shall not be bound by any terms of this Agreement until Tenant has
received a duplicate original of this Agreement executed by Lender.

     11.    Binding Effect.  This Agreement shall be binding upon the parties
            --------------
hereto, and their successors and assigns.  In addition, this Agreement shall be
binding upon any successor to Lender's interest as Landlord under the Lease.

     This Agreement has been executed by Lender and Tenant as of the ____ day of
_________, 2000.

                                     TENANT:

                                     _________________________________

                                     By:__________________________________
                                     Name:________________________________
                                     Title:_______________________________

                               Exhibit E, Page 5
<PAGE>

                                     LENDER:

                                     By:__________________________________
                                     Name:________________________________
                                     Title:_______________________________

                                     LANDLORD:

                                     ____________________________________

                                     By:__________________________________
                                     Name:________________________________
                                     Title:_______________________________

                               Exhibit E, Page 6
<PAGE>

                                   EXHIBIT F

                               GUARANTY OF LEASE
                               -----------------

  WHEREAS, Wells Operating Partnership, L.P., a Delaware limited partnership, as
Landlord ("Landlord"), and Enclave Parkway Realty, Inc., a Delaware corporation,
as Tenant ("Tenant"), are about to enter into a certain lease ("Lease") of even
date herewith of certain premises ("Leased Premises") located in Houston, Texas,
as more fully described in the Lease, and

  WHEREAS, Tenant is a wholly-owned subsidiary corporation of The Shaw Group,
Inc. a Louisiana corporation ("Guarantor"), and

  WHEREAS, Guarantor acknowledges that Landlord would not enter into the Lease
unless this Guaranty accompanied execution and delivery of the Lease.

  NOW, THEREFORE, in consideration of One ($1.00) Dollar and other valuable
consideration and to induce Landlord to enter into the Lease, Guarantor, having
an office at 8545 United Plaza Blvd.,  Baton Rouge, Louisiana, does hereby on
behalf of itself and its successors and assigns covenant and agree as follows:

  (a)     If Tenant, its successors or assigns, shall default at any time during
the term of the Lease (including any renewal terms) in the payment of Base Rent
(as defined in the Lease), additional rent, or other charges payable by Tenant
under the Lease, or in the observance or performance of any of the terms,
covenants or conditions of the Lease on Tenant's part to be observed or
performed, beyond the applicable grace period provided in the Lease for the
curing of such default, then Guarantor will, on demand, observe and perform said
terms, covenants and conditions and pay to Landlord all Base Rent, additional
rent and other charges payable under the Lease, together with all arrearages of
the foregoing

                               Exhibit F, Page 1
<PAGE>

amounts, all interest, fees, penalties, late fees, damages and expenses which
Landlord is entitled to recover pursuant to the terms of the Lease in
consequence of a default under the Lease, all reasonable costs and expenses that
may be incurred by Landlord in enforcing Tenant's covenants and agreements under
the Lease and all reasonable costs that may be incurred by Landlord in enforcing
the covenants and agreements of Guarantor hereunder, without requiring notice
from Landlord or any other person or entity;

  (b)     Guarantor may, at Landlord's option, be joined in any action or
proceeding commenced by Landlord against Tenant in connection with and based
upon the Lease or any term, covenant or condition thereof, and that recovery may
be had against Guarantor in such action or proceeding or any independent action
or proceeding against Guarantor without Landlord first asserting, prosecuting,
or exhausting any remedy or claim against Tenant, its successors or assigns;

  (c)     This Guaranty shall remain and continue in full force and effect as to
any renewal, extension, modification or amendment of the Lease and as to any
assignee of Tenant's interest in the Lease, and notwithstanding the fact that
any assignee of Tenant's interest in the Lease shall be released thereunder,
however, this Guaranty shall automatically terminate if Tenant assigns its
interest in the Lease to Guarantor, or if Tenant merges with Guarantor;

  (d)     (i)  This Guaranty constitutes an absolute, unconditional, present and
continuing guaranty of payment and not of collection and (ii) the validity of
this Guaranty and the obligations of Guarantor hereunder shall in no wise be
terminated, affected or impaired by reason of (A) any action which Landlord
and/or any lender of Landlord ("Lender") may take or fail to take against
Tenant, (B) any waiver of, or failure to enforce, any of the rights or remedies
reserved to Landlord in the Lease, or otherwise, (C) the bankruptcy or
insolvency of Tenant under the Lease and whether or not the term thereof shall

                               Exhibit F, Page 2
<PAGE>

terminate by reason of said bankruptcy or insolvency, (D) any set-off,
counterclaim, reduction or diminution of an obligation, or any defense of any
kind or nature (other than payment of the liabilities and obligations guaranteed
hereunder) which Guarantor or Tenant has or may have with respect to a claim
hereunder or under the Lease, or (E) any other occurrence or circumstance which
might otherwise constitute a legal or equitable discharge of a surety or
guarantor.  No invalidity, irregularity, contractual or other unenforceability
of all or any part of the liabilities and obligations guaranteed hereunder or of
any security therefor, shall affect, impair or be a defense to this Guaranty;

  (e)     In the event of termination of the Lease by reason of the occurrence
of an event of default enumerated in Section 12.1 of the Lease or in the event
of the disaffirmance or rejection of the Lease in any bankruptcy or insolvency
proceeding, and without limiting any of Landlord's rights under this Guaranty,
Guarantor shall, upon written request of Landlord, made within thirty (30) days
next following notice to Landlord of any such termination, disaffirmance or
rejection or, at any time thereafter, (i) pay to Landlord all Base Rent,
additional rent and other charges due and owing from Tenant to Landlord under
the Lease to and including the date of such termination, disaffirmance or
rejection, and (ii) enter, as "Tenant", into a new lease with Landlord, of the
Leased Premises demised in the Lease for a term commencing on the effective date
of such termination, disaffirmance or rejection, and ending on the date fixed in
the Lease for its natural expiration (unless such new lease shall be sooner
terminated as therein provided) at the same Base Rent and upon the same
executory terms, covenants and conditions as are contained in the Lease except
that (a) Guarantor's right as "Tenant" under the new lease shall be subject to
the possessory rights of Tenant under the Lease and the possessory rights of any
person, firm or corporation claiming by, through or under Tenant or by virtue of
any statute or of an order of any court, and (b) such new lease to Guarantor
shall require that all defaults existing under the Lease be cured by Guarantor
with due diligence, (iii) execute and deliver to Lender a subordination, non-
disturbance and attornment agreement (the "New Subordination

                               Exhibit F, Page 3
<PAGE>

Agreement") substantially identical to the subordination, non-disturbance and
attornment agreement of even date herewith executed by Tenant and (iv) deliver
to Landlord and Lender an opinion of counsel reasonably satisfactory to Landlord
and Lender stating that the new lease and the New Subordination Agreement are
duly executed, authorized and delivered. In the event Guarantor shall default in
its obligation to enter into said new lease and such default shall continue for
a period of ten (10) days next following Landlord's request therefor, then, in
addition to all other remedies by reason of such default, either at law or in
equity, Landlord shall have the same rights and remedies against Guarantor as if
Guarantor had entered into said new lease and said new lease had thereafter been
terminated, as at the commencement date thereof, by reason of Guarantor's
default thereunder;

  (f)     If Guarantor consolidates or merges with, or sells or otherwise
disposes of all or substantially all of its assets to any other individual,
corporation, company, partnership, association, trust or any other entity or
organization (herein referred to as a "Person"), in each case whether directly
or indirectly, and if Guarantor is not the survivor of such transaction, the
survivor shall (i) be a Person subject to the laws of a State of the United
States and (ii) expressly assume in writing Guarantor's obligations under this
Guaranty;

  (g)     Guarantor hereby waives notice of acceptance of this Guaranty and of
any liability to which it may apply, and notice or proof of reliance by Landlord
or Lender upon this Guaranty, and further waives diligence, presentment, demand
of payment, protest, notice of dishonor or nonpayment of any of the liabilities
and obligations guaranteed hereby, suit or taking other action or making any
demand against, and any other notice to, any Person liable thereon (including
Guarantor);

  (h)     If claim is ever made upon Landlord or Lender for repayment or
recovery of any amount or amounts received by Landlord or Lender in payment or
on account of the liabilities and obligations guaranteed hereunder and Landlord
or Lender repays to or for the

                               Exhibit F, Page 4
<PAGE>

benefit of Guarantor or Tenant or any of their respective creditors all or part
of such amount by reason of (i) any judgment, decree or order or any court or
administrative body having jurisdiction over Landlord or Lender, or (ii) any
settlement or compromise of any such claim effected by Landlord or Lender with
any such claimant (including Tenant), then and in such event Guarantor shall be
and remain liable under this Guaranty for the amount so repaid or recovered to
the same extent as if such amount had never originally been received by Landlord
or Lender;

  (i)     Nothing contained in this Guaranty shall be construed to give
Guarantor any direct or indirect claim, right or remedy against Tenant by reason
of this Guaranty and/or any performance by Guarantor, including, without
limitation, any claim, remedy or right of subrogation, reimbursement or
participation in any claim, right or remedy of Landlord or  Lender against
Tenant, and all such claims, rights or remedies are hereby waived.  Guarantor
will protect, indemnify and hold harmless Landlord and Lender from and against
all liabilities, obligations, claims, damages, penalties, causes of action,
costs, fees, charges and expenses (including, without limitation, reasonable
attorneys' fees and expenses) imposed upon or incurred by or asserted against it
or them by reason or arising out of any payment of Base Rent or additional rent
under the Lease being deemed or asserted to be voidable under the United States
Bankruptcy Code or any other bankruptcy or insolvency law, whether by reason of
being a preference or otherwise;

  (j)     Guarantor submits itself to the jurisdiction of the State of Texas in
any action or proceeding arising out of or under the Lease or this Guaranty, and
agrees that the laws of the State of Texas shall apply in any such action or
proceeding;

  (k)     Guarantor agrees that all notices, consents and other communications
under this Guaranty (collectively, "Notice" or "Notices") shall be in writing
and shall be deemed to have been given hereunder for all purposes (i) three (3)
days after having been sent by United States mail, by registered or certified
mail, return receipt requested, postage prepaid,

                               Exhibit F, Page 5
<PAGE>

addressed to the other party at its address as stated below, (ii) one (1) day
after having been sent by Federal Express or other nationally recognized air
courier service, to the addresses stated below or (iii) upon confirmation of
transmission via facsimile, provided that a conforming signed original is mailed
to the party to receive the notice on the date it is transmitted:

          To Landlord:
                    Wells Operating Partnership, L.P.
                    c/o Cardinal Capital Partners, Inc.
                    8411 Preston Road, Suite 850
                    Dallas, Texas 75225
                    Facsimile:  214-696-9845

          With a copy to Lender:
                    Guaranty Federal Bank, F.S.B.
                    8333 Douglas Avenue
                    Dallas, Texas 75225
                    Facsimile:  _________

          To Guarantor:
                    The Shaw Group, Inc.
                    Attn:  Walter R. Rhodes
                    8545 United Plaza Blvd.
                    Baton Rouge, Louisiana 70809
                    Facsimile: 225-925-9146

          With a copy to:
                    Office of General Counsel
                    Attn: Gary P. Graphia
                    The Shaw Group, Inc.
                    8545 United Plaza Blvd.
                    Baton Rouge, Louisiana 70809
                    Facsimile: 225-932-2642

  If any Lender shall have advised Guarantor by Notice in the manner aforesaid
that it is the holder of a mortgage on the Leased Premises and stating in said
Notice its address for the receipt of Notices, then simultaneously with the
giving of any Notice by Guarantor to Landlord, Guarantor shall serve one or more
copies of such Notice upon Lender in the

                               Exhibit F, Page 6
<PAGE>

manner aforesaid. For the purposes of this paragraph, any party may substitute
its address by giving fifteen (15) days notice to the other party in the manner
provided above;

  (l)     This Guaranty shall be interpreted and enforceable in accordance with
the laws of the State of Texas and shall be binding on Guarantor, its successors
and assigns, and shall enure to the benefit of Landlord and Lender, their and
each of their respective successors and assigns and all future owners of the
Leased Premises.  If any portion of this Guaranty is determined to be invalid or
unenforceable, the remainder of this Guaranty shall nevertheless continue in
full force and effect.  Any provision of this Guaranty which is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the
remaining provisions thereof, and any such prohibition or unenforceability in
any jurisdiction shall not invalidate or render unenforceable such provision in
any other jurisdiction;

  (m)     Neither this Guaranty nor any term hereof may be changed, waived,
discharged, amended, modified, extended or terminated orally, but only by an
instrument in writing signed by the party against which the enforcement of the
change, waiver, discharge or termination is sought, together with the written
consent of the Landlord, which consent may be withheld at Landlord's discretion.
Any such attempted change, waiver, discharge, amendment, modification, extension
or termination without such consent of the Landlord shall be void and of no
force and effect; and

  (n)     Guarantor hereby warrants and represents that Guarantor is the owner
and holder of all the issued and outstanding shares of Tenant and that the
execution and delivery of this Guaranty are not in contravention of its
Certificate of Incorporation or by-laws and have been authorized by its Board of
Directors and are in furtherance of its corporate purposes, and that said Board
of Directors has full authority under the said by-laws to authorize the
execution of this Guaranty and to validly bind Guarantor.

                               Exhibit F, Page 7
<PAGE>

  WITNESS the execution of this instrument as a sealed instrument as of the
_____day of _______________, 2000.

                              THE SHAW GROUP, INC.,
                              a Louisiana corporation

(Seal)
                              By:_____________________________

                                 Name:___________________________
                                 Title:__________________________

Attest:

_______________________
       Secretary

                               Exhibit F, Page 8
<PAGE>

STATE OF LOUISIANA

PARISH OF EAST BATON ROUGE

  On ________________, before me, ________________________ personally appeared
_______________________________________, personally known to me or proved to me
on the basis of satisfactory evidence to be the person(s) whose name(s) is/are
subscribed to the within instrument as the _________________ of The Shaw Group,
Inc., and acknowledged to me that he/she/they executed the same in his/her/their
authorized capacity(ies), and that by his/her/their signature(s) on the
instrument the person(s), or the entity upon behalf of which the person(s)
acted, executed this instrument.

WITNESS my hand and official seal.

-----------------------------
Signature of Notary

                               Exhibit F, Page 9
<PAGE>

                                   EXHIBIT G

                         Site Plan Showing Excess Land

                                  see attached

                               Exhibit G, Page 10
<PAGE>

                                  [SITE PLAN]

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