<PAGE>

                                                                   EXHIBIT 10.66

                  AGREEMENT FOR PURCHASE AND SALE OF PROPERTY

                       FOR THE STONE & WEBSTER BUILDING
<PAGE>

                AGREEMENT FOR THE PURCHASE AND SALE OF PROPERTY
                     1430 Enclave Parkway, Houston, Texas
                     ------------------------------------

     THIS AGREEMENT FOR THE PURCHASE AND SALE OF PROPERTY (the "Agreement"), is
made and entered into as of the 28 day of November, 2000, by and between
CARDINAL PARAGON, INC., a Texas corporation ("Seller"), and WELLS OPERATING
PARTNERSHIP, L.P., a Delaware limited partnership ("Purchaser").

                             W I T N E S S E T H:
                             - - - - - - - - - -

     WHEREAS, Cardinal Capital Partners, Inc., a Texas corporation ("Cardinal
Capital"), and Stone & Webster, Inc., a Louisiana corporation ("Stone"), have
executed an Agreement for Sale dated as of November 7, 2000 (the "Stone
Contract"), pursuant to which Cardinal Capital has the right to acquire the
Property (as defined herein); and

     WHEREAS, Cardinal Capital has assigned its rights under the Stone Contract
to Seller pursuant to an Assignment of Contract dated November 8, 2000; and

     WHEREAS, Seller desires to sell and Purchaser desires to purchase the
Property subject to the terms and conditions hereinafter set forth.

     NOW, THEREFORE, for and in consideration of the premises, the mutual
agreements contained herein, the sum of Ten Dollars ($10.00) in hand paid by
Purchaser to Seller at and before the sealing and delivery of these presents and
for other good and valuable consideration, the receipt, adequacy, and
sufficiency which are hereby expressly acknowledged by the parties hereto, the
parties hereto do hereby covenant and agree as follows:

     1.   Purchase and Sale of Property. Subject to and in accordance with
          -----------------------------
the terms and provisions of this Agreement, Seller hereby agrees to sell to
Purchaser and Purchaser hereby agrees to purchase from Seller, the Property,
which term "Property" shall mean and include the following:

          (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

          (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
     Seller, 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
<PAGE>

     owned by tenants of the building, are herein collectively referred to as
     the "Improvements"); and

          (d)  all personal property, if any, acquired by Seller from Stone 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 Seller's right, title, and interest, as landlord or
     lessor, in and to the Leases (as hereinafter defined); and

          (f)  all of Seller's right, title, and interest in and to any
     intangible property acquired by Seller from Stone relating to and
     reasonably required for the ownership and operation of the Property (but
     excluding any trade names or trade marks, any intangible property which
     relates to the operation of the business conducted by Stone), 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 Seller from Stone related to the ownership
     of or use and operation of the Land, Personal Property, or Improvements, if
     any (but not including the names "The Shaw Group, Inc.", "Stone & Webster,
     Inc." or any derivations thereof or logos therefor), all if and only to the
     extent acquired by Seller from Stone (herein, the "Intangible Property").

     2.   The Title Company and the Escrow Agent.  Alamo Title Company, located
          --------------------------------------
at 5251 Westheimer, Suite 200, Houston, Texas 77056 and Republic Title of Texas,
Inc., located at 2626 Howell, 10/th/ Floor, Dallas, Texas 75204, are referred to
herein as the "Title Company." Republic Title of Texas, Inc., located at 2626
Howell, 10th Floor, Dallas, Texas 75204, is referred to herein as the "Escrow
Agent".

     3.   Purchase Price and Earnest Money. (a) The purchase price (the
          --------------------------------
"Purchase Price") to be paid by Purchaser to Seller for the Property shall be
Forty-Four Million, Nine Hundred Seventy Thousand and No/100 Dollars
($44,970,000.00). The Purchase Price, less the Seller's Loan (as hereinafter
defined), shall be paid by Purchaser by wire transfer of immediately available
funds to the Escrow Agent for immediate disbursement at Closing (as hereinafter
defined), subject to adjustment and credits as otherwise specified in this
Agreement.

     (b)  Upon execution of this Agreement, Purchaser shall deliver to the
Escrow Agent One Million and No/100 Dollars ($1,000,000.00) (in immediately
available funds) as earnest money (the "Earnest Money"), which funds shall be
                                        -------------
deposited and held by the Escrow Agent in an interest bearing account. In the
event the transaction contemplated by this Agreement is closed, the Earnest
Money will be applied in payment of the Purchase Price to be paid at Closing. In
the event the transaction is not closed, the Earnest Money shall be disbursed in
accordance with the provisions of this Agreement.
<PAGE>

     (c)  Prior to the expiration of the Feasability Period (as hereinafter
defined), Purchaser shall deliver to the Escrow Agent an additional Five Hundred
Thousand and No/100 Dollars ($500,000.00) (in immediately available funds) as
additional Earnest Money, which funds shall be deposited and held by the Escrow
Agent with the previously delivered Earnest Money in an interest bearing
account. In the event the transaction contemplated by this Agreement is closed,
the Earnest Money will be applied in payment of the Purchase Price to be paid at
Closing. In the event the transaction is not closed, the Earnest Money shall be
disbursed in accordance with the provisions of this Agreement.

     4.   Purchaser's Inspection and Review Rights. (a) During the Feasability
          ----------------------------------------
Period, Purchaser and its agents, engineers, or representatives shall have the
privilege, by coordinating their activities with Seller, of going upon the
Property as needed to inspect, examine, test, and survey the Property. After the
Feasability Period, and upon the request of Purchaser, Seller shall use its
reasonable efforts to allow Purchaser access to the Property. Purchaser hereby
agrees to indemnify and hold Seller and Stone harmless from any liens, claims,
liabilities, and damages incurred through the exercise of such privilege; and
Purchaser, under the direction of Seller, further agrees to repair any damage to
the Property caused by the exercise of such privilege. Such obligations shall
survive any termination of this Agreement. Seller has made available to
Purchaser, or Purchaser's agents and representatives, for review and copying,
all books, records, files and other information in Seller's possession relating
to the ownership and operation of the Property, including, without limitation,
any tenant files, and other contracts, books, records, operating statements, and
other information relating to the Property obtained from Stone or independently
developed by Seller. Seller has provided to Purchaser prior to the date hereof
any appraisals, building inspection reports, environmental reports and financial
information relating thereto which is in the possession or under the control of
Seller.

     (b)  The Feasability Period shall commence on the date hereof and end
at 6:00 p.m., Dallas, Texas time, December 14, 2000, TIME BEING OF THE ESSENCE.
                                                     -------------------------
If Purchaser determines, in its sole judgment, that the Property is not suitable
for any reason for Purchaser's intended use or purpose, or is not in
satisfactory condition, then Purchaser may terminate this Agreement by written
notice to Seller prior to the expiration of the Feasability Period, in which
case the Earnest Money will be returned to Purchaser, and neither party shall
have any further right or obligation hereunder other than as set forth herein
with respect to rights or obligations which survive termination. If the
Agreement is not terminated in the manner and within the time provided in this
Subsection 4(b), TIME BEING OF THE ESSENCE, the option for Purchaser to
                 -------------------------
terminate this Agreement pursuant to the terms of this Subsection 4(b) shall be
deemed to have been waived by Purchaser.

          (c)  Notwithstanding anything herein to the contrary, in the event
that Purchaser gives Seller notice prior to the expiration of the Feasability
Period that Purchaser desires to terminate this Contract due to an
unsatisfactory condition of the slab of concrete on the Land (the "Slab") and
Purchaser simultaneously therewith certifies to Seller the nature of such
unsatisfactory condition of the Slab (the "Unsatisfactory Condition"), Seller
shall have until 6:00 p.m., Central Time, on January 15, 2001 (the "Cure
Period"), in which to cure the Unsatisfactory Condition. In
<PAGE>

the event that Seller cures the Unsatisfactory Condition prior to the expiration
of the Cure Period, notwithstanding anything herein to the contrary, the Closing
Date shall be deemed to be the date that is two weeks subsequent to the date
that Purchaser receives notice that the Unsatisfactory Condition has been cured.
In the event that Seller fails to cure the Unsatisfactory Condition prior to the
expiration of the Cure Period, this Contract shall be deemed terminated as of
the expiration of the Cure Period. Nothing herein shall obligate Seller to cure
the Unsatisfactory Condition.

     5.   Special Condition Precedent to Seller's Obligations. (a) Purchaser
          ---------------------------------------------------
specifically acknowledges that Seller has contracted with Stone to acquire the
Property from Stone and enter into the Stone Lease (hereinafter defined). In the
event that Seller is unable to acquire the Property for any reason other than
Seller's willful default under the Stone Contract, Purchaser's sole right shall
be to terminate this Agreement whereupon Purchaser and Seller shall thereafter
be excused from all obligations of one to the other, except those obligations
which expressly survive any termination of this Agreement. The date of Closing
hereunder shall occur simultaneously with closing under the Stone Contract,
which is scheduled for twenty-two (22) days after the expiration of the
Feasability Period (the "Closing Date"), for which TIME SHALL BE OF THE ESSENCE
                                                   ----------------------------
with respect to Purchaser's obligations hereunder, and Seller and Purchaser
agree to cooperate with each other to close on such date. If Closing hereunder
does not occur simultaneously with closing under the Stone Contract, then
Purchaser shall pay for the premium for the owner's policy of title insurance.

     (b)  In lieu of transferring the Property to Purchaser as provided in this
Agreement, Seller shall be entitled to direct Stone to convey title directly to
Purchaser (provided the Deed satisfies the provisions of Section 11(a)) and to
enter into the Stone Lease directly with Purchaser. If Seller elects to direct
Stone to convey title directly to Purchaser, Seller shall provide Purchaser
notice of such election at lest three (3) days prior to the Closing Date. In
such event, (i) Purchaser and Stone shall directly enter into the Stone Lease,
as provided herein, (ii) there shall be no prorations between Purchaser and
Seller under Section 14 hereof, but Seller shall cause Stone to prorate with
Purchaser all ad valorem real estate taxes and assessments levied or assessed
against the Property according to the calendar year as of the Closing Date,
based on the most recent tax bill for the Property, and such other items as are
normally and customarily proratable and are proratated by Stone, (iii) Seller
shall not be obligated to deliver the documents referred to in Section 11
(except that Seller will cause the documents set forth in Sections 11 to be
delivered to Purchaser at the Closing), and (iv) Purchaser shall not be
obligated to deliver the documents referred to in Sections 12 to Seller and
shall instead be obligated to deliver such documents to Stone.

     6.   General Conditions Precedent to Purchaser's Obligations Regarding
          -----------------------------------------------------------------
the Closing. In addition to the conditions to Purchaser's obligations set forth
-----------
in Paragraph 5 above, the obligations and liabilities of Purchaser hereunder
shall in all respects be conditioned upon the satisfaction of each of the
following conditions, any of which may be waived by written notice from
Purchaser to Seller:
<PAGE>

          (a)  Compliance by Seller. Seller shall have complied in all material
               --------------------
     respects with and otherwise performed in all material respects each of the
     covenants and obligations of Seller set forth in this Agreement as of the
     date of Closing.

          (b)  Seller's  Representations.  All representations and warranties of
               -------------------------
     Seller as set forth in this Agreement shall be true and correct in all
     material respects as of the date of Closing.

          (c)  No Adverse Changes. There shall have been no adverse change to
               ------------------
     the title to the Property which has not been cured, and the Title Company
     shall have issued the Title Commitment (as hereinafter defined) on the Land
     and Improvements without exceptions other than as described in paragraph 7
     and the Title Company shall be prepared to issue to Purchaser upon the
     Closing an owner's title insurance policy on the Land and Improvements
     pursuant to such Title Commitment.

          (d)  Tenant Estoppels. Purchaser shall have received a tenant estoppel
               ----------------
     certificate duly executed by Sysco Corp. ("Sysco") at or prior to Closing
     in a form approved by Purchaser prior to the expiration of the Feasability
     Period, and, if Purchaser is not a named party to the Stone Lease, a tenant
     estoppel from Stone in the form of estoppel provided by Sysco.

          (e)  Leases. Attached hereto as Exhibit "B-1" is a true and accurate
               ------                     ------------
     copy of that certain lease dated July 20, 1998, between Enclave Parkway
     Realty, Inc. and Sysco (said lease is referred to herein as the "Sysco
     Lease"). Attached hereto as Exhibit "B-2" is a true and accurate copy of a
                                 ------------
     Lease (the "Stone Lease") to be entered into by and between Seller and
     Stone at the Closing. The Sysco Lease and the Stone Lease are hereinafter
     collectively defined as the "Leases." Sysco and Stone are hereinafter
     collectively known as "Tenants". As of the Closing, the Leases shall be in
     full force and effect; and, subject to the provisions of Section 5 hereof,
     Seller shall be the "landlord" under the Leases, and Seller shall own
     unencumbered legal and beneficial title thereto and the rents and other
     income thereunder. The Stone Lease shall be guaranteed by The Shaw Group,
     Inc., a Texas corporation ("Shaw") pursuant to a Guaranty of Lease attached
     hereto and made a part hereof as Exhibit B-3
                                      -----------

          (f)  Lease - Rents and Special Consideration. The Tenants shall: (i)
               ---------------------------------------
     not have prepaid rent for more than the current month under the Leases,
     (ii) not have received and shall not be entitled to receive any rent
     concession in connection with its tenancy under the Leases other than as
     described in the Leases, (iii) not be entitled to any special work (not yet
     performed), or consideration (not yet given) in connection with its tenancy
     under the Leases, and (iv) not have any deed, option, or other evidence of
     any right or interest in or to the Property, except for the Tenants'
     tenancy as evidenced by the express terms of the Leases.

          (g)  Lease - Acceptance of Premises. (i) the Tenants shall have
               ------------------------------
     accepted their leased premises located within the Property, including any
     and all work performed therein
<PAGE>

     or thereon pursuant to the Leases, (ii) the Tenants shall be in full and
     complete possession of their respective premises under the Leases, and
     (iii) neither Seller nor Stone shall have received notice from a Tenant
     that such Tenant's premises are not in full compliance with the terms and
     provisions of the Tenant's Lease or are not satisfactory for the Tenant's
     purposes.

          (h)  No Other Agreements. Other than the Leases, the Permitted
               -------------------
     Exceptions (as hereinafter defined), and such other service, utility,
     maintenance and other contracts or agreements, and union or other
     collective bargaining contracts currently in effect with respect to the
     Property (collectively, the "Service Contracts") of which Purchaser may
     receive copies within seven (7) days of the date hereof, there shall be no
     leases, service contracts, management agreements, or other agreements or
     instruments in force and effect, oral or written, to which Seller is a
     party and that grant to any person whomsoever or any entity whatsoever any
     right, title, interest or benefit in or to all or any part of the Property
     or any rights relating to the use, operation, management, maintenance, or
     repair of all or any part of the Property.

          (i)  No Litigation. Except for a dispute relating to the purported
               -------------
     termination of the tax abatement agreements with Harris County, Houston
     Independent School District and other tax authorities affecting the
     Property (the "Tax Dispute"), there shall be no actions, suits, or
     proceedings pending, or, to Seller's actual knowledge but without any duty
     of investigation whatsoever on the part of Seller other than
     representations made by Stone to Seller in the Stone Contract
     (collectively, "Seller's Knowledge"), threatened by any organization,
     person, individual, or governmental agency against Seller with respect to
     the Property; and, to Seller's Knowledge, there shall be no actions, suits
     or proceedings at law or in equity by or before any Governmental Authority
     (as hereinafter defined) or other agency now pending and served or, to
     Seller's Knowledge, threatened against Stone and affecting the Property.

          (j)  Condemnation. There shall be no pending or, to Seller's
               ------------
     Knowledge, threatened condemnation or eminent domain proceedings (or
     proceedings in the nature or in lieu thereof) affecting the Property or any
     portion thereof or its use.

          (k)  Proceedings Affecting Access. There shall be no pending or
               ----------------------------
     threatened condemnation proceedings that could have the effect of impairing
     or restricting access between the Property and adjacent public roads.

          (l)  SNDA's. Purchaser shall have received a Subordination,
               ------
     Non-Disturbance and Attornment Agreement in a form reasonably acceptable to
     the Bank (as hereinafter defined) with respect to the Leases.

     7.   Title and Survey. Seller shall cause the Title Company, at
          ----------------
Seller's cost and expense, to deliver to Purchaser, within seven (7) days of the
date hereof, its commitment (herein referred to as the "Title Commitment") to
issue to Purchaser, upon the recording of the Deed conveying title
<PAGE>

to the Land and Improvements from Seller to Purchaser, the payment of the
Purchase Price (whether by Seller or Purchaser, as provided hereunder), and the
payment to the Title Company of the policy premium therefor, an owner's policy
of title insurance, in the amount of the Purchase Price, insuring record title
to the Land and Improvements to be in Purchaser subject only to the Permitted
Exceptions (as hereinafter defined) and containing the standard printed
exceptions, provided, however, there shall be no exception for mechanics' or
materialmen's liens, the exception for taxes shall refer to the year 2000, and
any exception for parties in possession shall be limited to rights of Tenants,
as tenants only, pursuant to the Leases. The survey exception may be amended to
except only the "shortages in area." Seller shall also cause to be delivered to
Purchaser, together with such Title Commitment, legible copies of all documents
and instruments referred to therein and a current "as-built" survey of the Land
and Improvements. Purchaser will, by the expiration of the Feasability Period,
have examined the Title Commitment, the exception documents and the survey. The
matters set forth on such survey and in the Title Commitment shall be referred
to herein as the "Permitted Exceptions."

     8.   Representations and Warranties of Seller.  Seller hereby makes the
          ----------------------------------------
following representations and warranties to Purchaser, each of which shall be
deemed material:

          (a)  Lease - Assignment. To Seller's Knowledge, no Tenant has assigned
               ------------------
     its interest in a Lease or sublet any portion of the premises leased to
     each such Tenant under a Lease.

          (b)  Lease - Default. (i) Seller has not received any notice of
               ---------------
     termination or default under any Lease and does not know of Stone receiving
     the same, (ii) Seller knows of no existing or uncured defaults by a Tenant
     under the Leases, (iii) to Seller's Knowledge, no Tenant has asserted any
     defense, set-off, or counterclaim with respect to its tenancy or its
     obligation to pay rent, additional rent, or other charges pursuant to the
     Leases.

          (c)  Lease - Commissions. No rental, lease, or other commissions with
               -------------------
     respect to the Leases are payable to Seller, any partner of Seller, any
     party affiliated with or related to Seller or any partner of Seller or, to
     Seller's Knowledge, any third party. Any commissions payable under,
     relating to, or as a result of the Leases shall have been paid and
     satisfied in full as of the Closing.

          (d)  No Assessments. Except for the Tax Dispute, to Seller's
               --------------
     Knowledge, no assessments have been made against the Property that are
     unpaid, whether or not they have become liens.

          (e)  Conditions of Improvements. To Seller's Knowledge, there is no
               --------------------------
     structural or other defects in the Improvements.

          (f)  Violations. Except for the Tax Dispute, to Seller's Knowledge,
               ----------
     there is no violation of law, municipal or county ordinances, or other
     legal requirements with respect to the Property.
<PAGE>

          (g)  Bankruptcy. Seller is "solvent" as said term is defined by
               ----------
     bankruptcy law and has not made a general assignment for the benefit of
     creditors nor been adjudicated a bankrupt or insolvent, nor has a receiver,
     liquidator, or trustee for any of Seller's properties (including the
     Property) been appointed or a petition filed by or against Seller for
     bankruptcy, reorganization, or arrangement pursuant to the Federal
     Bankruptcy Act or any similar Federal or state statute, or any proceeding
     instituted for the dissolution or liquidation of Seller.

          (h)  Pre-existing Right to Acquire. Seller has granted no person or
               -----------------------------
     entity any right or option to acquire the Property or any portion thereof
     which will have any force or effect after the execution of this Agreement,
     other than Purchaser.

          (i)  Authorization. Seller is a duly organized and validly existing
               -------------
     corporation under the laws of the State of Texas. This Agreement has been
     duly authorized and executed on behalf of Seller and constitutes the valid
     and binding agreement of Seller, enforceable in accordance with its terms,
     and all necessary action on the part of Seller to authorize the
     transactions herein contemplated has been taken, and no further action is
     necessary for such purpose.

          (j)  Seller Not a Foreign Person. Seller is not a "foreign person"
               ---------------------------
     which would subject Purchaser to the withholding tax provisions of Section
     1445 of the Internal Revenue Code of 1986, as amended.

     AS A CONDITION PRECEDENT TO SELLER'S UNDERTAKINGS AND AGREEMENTS HEREUNDER,
SELLER EXPRESSLY DISCLAIMS AND PURCHASER ACKNOWLEDGES AND ACCEPTS THAT SELLER
HAS DISCLAIMED MAKING ANY REPRESENTATIONS, WARRANTIES, OR ASSURANCES WITH
RESPECT TO THE PROPERTY OTHER THAN AS SPECIFICALLY SET OUT HEREIN. OTHER THAN AS
SPECIFICALLY SET OUT HEREIN, PURCHASER AGREES THAT WITH RESPECT TO THE PROPERTY
IT WILL RELY UPON ITS INSPECTIONS THEREOF OR ITS DETERMINATIONS NOT TO INSPECT
THE SAME, AND UPON CLOSING SHALL ACCEPT THE PROPERTY IN ITS "AS IS" CONDITION,
WITH ALL FAULTS, AND WITHOUT REFERENCE TO MERCHANTABILITY OR FITNESS FOR ANY
SPECIFIC PURPOSE.

     9.   Seller's  Additional  Covenants.  Seller does hereby further covenant
          -------------------------------
and agree as follows, if and to the extent that the Closing shall occur after
the execution hereof:

          (a)  Operation of Property. Seller hereby covenants that, from the
               ---------------------
     date of Seller's acquisition of the Property up to and including the date
     of Closing or earlier termination of this Agreement, Seller shall: (i) not
     modify, amend, or terminate any Lease or enter into any new lease,
     contract, or other agreement respecting the Property, (ii) not grant or
     otherwise create or consent to the creation of any easement, restriction,
     lien, assessment, or encumbrance respecting the Property, and (iii) cause
     the Property to be operated,
<PAGE>

     maintained, and repaired in the same manner as the Property is currently
     being operated, maintained, and repaired.

          (b)  Preservation of Lease. Seller shall, from and after the date of
               ---------------------
     Seller's acquisition of the Property to the date of Closing, use its good
     faith efforts to perform and discharge all of the duties and obligations
     and shall otherwise comply with every covenant and agreement of the
     landlord under the Lease, at Seller's expense, in the manner and within the
     time limits required thereunder. Furthermore, Seller shall, for the same
     period of time, use diligent and good faith efforts to cause the Tenants
     under the Leases to perform all of their duties and obligations and
     otherwise comply with each and every one of its covenants and agreements
     under such Leases and shall take such actions as are reasonably necessary
     to enforce the terms and provisions of the Leases.

     10.  Closing. Provided that all of the conditions set forth in this
          -------
Agreement are theretofore fully satisfied or performed, it being fully
understood and agreed, however, that Purchaser may expressly waive in writing,
at or prior to Closing, any conditions that are unsatisfied or unperformed at
such time, the consummation of the sale by Seller and purchase by Purchaser of
the Property (herein referred to as the "Closing") shall be held at 2:00 p.m.,
local time, on or before the date that is twenty-two (22) days after the
expiration of the Feasability Period.

     11.  Seller's Closing Documents. For and in consideration of, and as a
          --------------------------
condition precedent to, Purchaser's delivery to Seller of the Purchase Price
described in Paragraph 3 hereof, Seller shall obtain or execute, at Seller's
expense, and deliver to Purchaser at Closing the following documents (all of
which shall be duly executed, acknowledged, and notarized where required and
shall survive the Closing):

          (a)  Special Warranty Deed. A Special Warranty Deed conveying to
               ---------------------
     Purchaser title to the Land and Improvements, together with all rights,
     easements, and appurtenances thereto, if any, subject only to the Permitted
     Exceptions. The legal description set forth in the Special Warranty Deed
     shall be as set forth on Exhibit "A;"
                              ------------

          (b)  Bill of Sale. A Bill of Sale conveying to Purchaser title to the
               ------------
     Personal Property in a form approved by Purchaser prior to the expiration
     of the Feasability Period, which form shall be in substantially the same
     form and substance as the bill of sale to Seller from Stone;

          (c)  Assignment of Intangible Property. An Assignment of Intangible
               ---------------------------------
     Property, including all construction warranties and guarantees that Seller
     receives from Stone, such Assignment of Intangible Property to be in
     substantially the same the form and substance as the assignment of
     intangible property to Seller from Stone and as set forth in Exhibit C;
                                                                  ---------

          (d)  Assignment and Assumption of Leases. An Assignment and Assumption
               -----------------------------------
     of Leases in a form approved by Purchaser prior to the expiration of the
     Feasability Period, which form shall be in substantially the same form and
     substance as the assignment and
<PAGE>

         assumption of leases between Seller and Stone, assigning to Purchaser
         all of Seller's right, title, and interest in and to the Leases and the
         rents thereunder;

               (e) Memorandum of Lease. The Memorandum of Lease for the portion
                   -------------------
         of the Property to be leased to Stone at the Closing, in the form of
         Exhibit D duly executed and acknowledged by Stone in recordable form.
         ---------

               (f) Assignment of Service Contracts. An Assignment of any
                   -------------------------------
         assignable Service Contracts in a form approved by Purchaser prior to
         the expiration of the Feasability Period, which form shall be in
         substantially the same form and substance as the assignment from Stone
         to Seller.

               (g) FIRPTA Certificate. A FIRPTA Certificate in such form as
                   ------------------
         required by the Internal Revenue Service;

               (h) Certificates of Occupancy. Any original certificates of
                   -------------------------
         occupancy that Seller receives from Stone;

               (i) Keys, Records, Etc. Any keys to doors or locks on the
                   ------------------
         Property, any original tenant files, books and records relating to the
         Property and any other item which Seller receives from Stone;

               (j) Tenant Notice. Notice from Seller to the Tenants of the sale
                   -------------
         of the Property to Purchaser in such form as Purchaser shall reasonably
         approve;

               (k) Settlement Statement. A settlement statement setting forth
                   --------------------
         the amounts paid by or on behalf of and/or credited to each of
         Purchaser and Seller pursuant to this Agreement; and

               (l) Evidence of Issuance of Title Commitment. Purchaser shall
                   ----------------------------------------
         receive reasonable assurance that the Title Company will issue an
         owner's title policy in the form required hereby, with an effective
         date as of the date and time of recording the Special Warranty Deed,
         reflecting that Purchaser is vested with title to the Land and
         Improvements, and to reflect that all requirements for the issuance of
         the same have been satisfied.

               (m) Assignment of Rights. An Assignment by Seller to Purchaser of
                   --------------------
         such rights of Seller under the Stone Contract as are assignable.

               (n) Other Documents. An agreement by Stone and Shaw, in favor of,
                   ---------------
         among other entities, Purchaser, the Bank and the Title Company
         (collectively, the "Indemnitees") in form satisfactory to the
         Indemnitees, indemnifying and holding harmless the Indemnitees from all
         claims, suits, liabilities, obligations, debts, damages, fines,
         penalties, interest, charges, including court costs and reasonable
         attorney's fees relating to all taxes due or claimed to be due with
         respect to the Property covering the period prior to the Closing Date
<PAGE>

         relating to the Tax Dispute. Stone shall not be required to pay such
         taxes at Closing, but if requested by the Title Company or the Bank,
         Seller shall request that Stone deposit the total amount of taxes
         claimed to be due by the applicable taxing authorities together with
         such additional amounts as required by the Title Company to cover
         additional penalties and interest at Closing with the Title Company.
         Such agreement of Stone and Shaw shall expressly provide that it
         survives the Closing and the delivery of the Speical Warranty Deed.

               (o) Other Documents. Such other documents as shall be reasonably
                   ---------------
         required in order to close this transaction.

         12.   Purchaser's Closing Documents. Purchaser shall obtain or execute
               -----------------------------
and deliver to Seller at Closing the following documents, all of which shall be
duly executed by Purchaser and acknowledged where required and shall survive the
Closing:

               (a) Bill of Sale. The Bill of Sale;
                   ------------

               (b) Assignment and Assumption of Lease. The Assignment and
                   ----------------------------------
         Assumption of Leases;

               (c) Settlement Statement. A settlement statement setting forth
                   ---------------------
         the amounts paid by or on behalf of and/or credited to each of
         Purchaser and Seller pursuant to this Agreement;

               (d) Assignment of Intangible Property. Four (4) counterpart
                   ---------------------------------
         originals of the Assignment of Intangible Property, such Assignment of
         Intangible Property to be in substantially the same the form and
         substance as the assignment of intangible property set forth in Exhibit
         C;                                                              -------
         -
               (e) Memorandum of Lease. Four (4) counterpart originals of the
                   -------------------
         Memorandum of Lease for the Stone Lease, which Memorandum of Lease
         shall be in the form set forth in Exhibit D;
                                           ---------

               (f) Assumption of Service Contracts. An assumption by Purchaser
                   -------------------------------
         of the obligations of the owner of the Property under the Service
         Contracts except with respect to those Service Contracts that are
         terminated by Purchaser; and

               (g) Other Documents. Such other documents as shall be reasonably
                   ---------------
         required by Seller's counsel.

         13.   Closing Costs. Seller shall pay the cost of the Title Commitment,
               -------------
including the cost of the examination of title to the Property made in
connection therewith, the premium for the owner's policy of title insurance
issued pursuant thereto (except to the extent the same is payable by Purchaser
as provided in Section 5 above), the cost of the as-built survey, the attorneys'
fees of
<PAGE>

Seller, and all other costs and expenses incurred by Seller in closing and
consummating the purchase and sale of the Property pursuant hereto. Purchaser
shall pay the attorneys' fees of Purchaser, and all other costs and expenses
incurred by Purchaser in closing and consummating the purchase and sale of the
Property pursuant hereto, including third-party inspection fees. Each party
shall pay one-half of any escrow fees.

         14.   Prorations.  Subject to the  provisions of Section 5 hereof, the
               ----------
following items shall be prorated and/or credited between Seller and Purchaser
as of the 11:59 PM immediately preceding the date of Closing:

               (a) Rents. Rents, additional rents, and other income of the
                   -----
         Property (other than security deposits, which shall be assigned and
         paid over to Purchaser) collected by Seller from Tenants for the month
         of Closing. Purchaser shall also receive a credit against the Purchase
         Price payable by Purchaser to Seller at Closing for any rents or other
         sums (not including security deposits) prepaid by Tenants for any
         period following the month of Closing, or otherwise.

               (b) Property Taxes; Utility Charges and Other Operating Expenses.
                   ------------------------------------------------------------
         City, state, county, and school district ad valorem taxes, utility
         charges and other operating expenses, and such taxes will be further
         adjusted, if necessary, upon receipt of the actual tax bill for the
         period adjusted. If such further adjustment is necessary, the same
         shall be adjusted between Stone and Purchaser, so that Purchaser shall
         pay any amount owing to Stone and shall receive any amount due from
         Stone. This agreement to adjust shall survive Closing.

         15.   Purchaser's Default. In the event Purchaser fails to close,
               -------------------
Seller's sole and exclusive remedy shall be to terminate this Agreement and
receive the Earnest Money as liquidated damages; Purchaser and Seller hereby
agree that actual damages would be difficult or impossible to ascertain and such
amount is a reasonable estimate of the damages for such breach or failure, and
thereafter the parties hereto shall have no further rights or obligations
hereunder whatsoever, except as to matters expressly surviving termination.
Seller shall not be limited with respect to any matters expressly surviving such
termination.

              Seller's Initial     GB         Purchaser's Initials     DPW
                              --------------                       ------------

         16.   Seller's Default. In the event Seller fails to close or otherwise
               ----------------
defaults with respect to Closing obligations, (i) Purchaser shall have the right
to terminate this Agreement by giving written notice of such termination to
Seller, whereupon Purchaser and Seller shall have no further rights,
obligations, or liabilities hereunder, except as may be expressly provided to
the contrary herein; or (ii) Purchaser shall have the right to accept title to
the Property subject to defects and objections with no reduction in the Purchase
Price (except for monetary encumbrances, arising by, through or under Seller),
in which event such defects and objections shall be deemed "Permitted
Exceptions;" or (iii) Purchaser may elect to seek specific performance of this
Agreement. Purchaser shall not be limited with respect to any matters expressly
surviving the termination of this Agreement.
<PAGE>

         17.   Condemnation. If, prior to the Closing, all or any part of the
               ------------
Property is subjected to a bona fide threat of condemnation by a body having the
power of eminent domain or is taken by eminent domain or condemnation (or sale
in lieu thereof), or if Seller has received notice that any condemnation action
or proceeding with respect to the Property is contemplated by a body having the
power of eminent domain, Seller shall give Purchaser immediate written notice of
such threatened or contemplated condemnation or of such taking or sale, and
Purchaser may by written notice to Seller given within thirty (30) days of the
receipt of such notice from Seller, elect to cancel this Agreement. If Purchaser
chooses to cancel this Agreement in accordance with this Paragraph 17, then the
rights, duties, obligations, and liabilities of the parties hereunder shall
immediately terminate and be of no further force and effect. If Purchaser does
not elect to cancel this Agreement in accordance herewith, this Agreement shall
remain in full force and effect and the sale of the Property contemplated by
this Agreement, less any interest taken by eminent domain or condemnation, or
sale in lieu thereof, shall be effected with no further adjustment and without
reduction of the Purchase Price, and at the Closing, Seller shall assign,
transfer, and set over to Purchaser all of the right, title, and interest of
Seller in and to any awards that have been or that may thereafter be made for
such taking.


         18.   Damage or Destruction. If any of the Improvements shall be
               ---------------------
destroyed or damaged prior to the Closing, and the estimated cost of repair or
replacement exceeds Five Hundred Thousand Dollars ($500,000.00) or if a Lease
shall terminate as a result of such damage, Purchaser may, by written notice
given to Seller within twenty (20) days after receipt of written notice from
Seller of such damage or destruction, elect to terminate this Agreement, in
which event, except as expressly provided herein to the contrary, the rights,
duties, obligations, and liabilities of all parties hereunder shall immediately
terminate and be of no further force or effect. If Purchaser does not elect to
terminate this Agreement pursuant to this Paragraph 18, or has no right to
terminate this Agreement (because the damage or destruction does not exceed
$500,000.00 and the Leases remain in full force and effect), and the sale of the
Property is consummated, Purchaser shall be entitled to receive all insurance
proceeds paid or payable to Seller by reason of such destruction or damage under
the insurance maintained by Seller (less amounts of insurance theretofore
received and applied by Seller to restoration). If the amount of said casualty
or rent loss insurance proceeds is not settled by the date of Closing, Seller
shall execute at Closing all proofs of loss, assignments of claim, and other
similar instruments to ensure that Purchaser shall receive all of Seller's
right, title, and interest in and under said insurance proceeds.

         19.   Hazardous Substances. Seller hereby warrants and represents,to
               --------------------
Seller's Knowledge, that (i) no "hazardous substances," as that term is defined
in the Comprehensive Environmental Response, Compensation and Liability Act of
1980, as amended, 42 U.S.C. Section 9601, et. seq., the Resource Conservation
                                          --  ---
and Recovery Act, as amended, 42 U.S.C. Section 6901 et. seq., and the rules and
                                                     --  ---
regulations promulgated pursuant to these acts, any so-called "super-fund" or
"super-lien" laws or any applicable state or local laws, nor any other
pollutants, toxic materials, or contaminants have been or shall prior to Closing
be discharged, disbursed, released, disposed of, or allowed to escape on the
Property, (ii) no asbestos or asbestos containing materials are present on the
Land and Improvements, except in amounts permitted under applicable
environmental laws, (iii) no polychlorinated biphenyls are located on or in the
Land and Improvements except in amounts
<PAGE>

permitted under applicable environmental laws, (iv) no underground storage tanks
for Hazardous Substances are located on the Property, and (v) no investigation,
administrative order, consent order and agreement, litigation, or settlement
with respect to Hazardous Substances is proposed, threatened, anticipated or in
existence with respect to the Property.

         20.   Assignment.  Purchaser's  rights and duties  under this
               ----------
Agreement shall not be assignable except to an affiliate of Purchaser without
the consent of Seller which consent shall not be unreasonably withheld. Seller
may assign this Agreement to an affiliate of Seller formed to take title to the
Property.

         21.   Broker's Commission. Purchaser and Seller hereby represent, each
               -------------------
to the other, that they have not discussed this Agreement or the subject matter
hereof with any real estate broker or agent other than The Roylston Group
("Broker"), which Seller agrees to pay pursuant to a separate agreement, so as
to create any legal right in any such broker or agent to claim a real estate
commission with respect to the conveyance of the Property contemplated by this
Agreement. Seller shall and does hereby indemnify and hold harmless Purchaser
from and against any claim, whether or not meritorious, for any real estate
sales commission, finder's fees, or like compensation in connection with the
sale contemplated hereby and arising out of any act or agreement of Seller.
Likewise, Purchaser shall and does hereby indemnify and hold harmless Seller
from and against any claim, whether or not meritorious, for any real estate
sales commission, finder's fees, or like compensation in connection with the
sale contemplated hereby and arising out of any act or agreement of Purchaser.
This Paragraph 21 shall survive the Closing or any termination of this
Agreement.

         22.   Notices. Wherever any notice or other communication is required
               -------
or permitted hereunder, such notice or other communication shall be in writing
and shall be delivered by overnight courier or by hand to the addresses set out
below or at such other addresses as are specified by written notice delivered in
accordance herewith:

         PURCHASER:                     c/o Wells Capital, Inc.
                                        6200 The Corners Parkway, Suite 250
                                        Norcross, Georgia 30092
                                        Attn: Mr. Michael C. Berndt
                                        Fax No. 770-840-7224

         with a copy to:                O'Callaghan & Stumm LLP
                                        127 Peachtree Street, N. E., Suite 1330
                                        Atlanta, Georgia 30303
                                        Attn: William L. O'Callaghan, Esq.
                                        Fax No. 404-522-3080

         SELLER:                        c/o Cardinal Capital Partners, Inc.
                                        Attn: Mr. Gil J. Besing
                                        8411 Preston Road, Suite 850

<PAGE>

                                        Dallas, Texas 75225
                                        Fax No. 214-696-9845

         with a copy to:                Goldfarb & Fleece
                                        Attn: Steven B. Shore, Esq.
                                        345 Park Avenue, 33/rd/ Fl.
                                        New York, New York 10154
                                        Fax No. 212-751-3738

         Any notice or other communication sent as hereinabove provided shall be
deemed effectively given or received on the date of delivery whether delivered
by hand or by overnight courier.

         23.   Possession.   Possession of the Property  shall be granted by
               ----------
Seller to Purchaser on the date of Closing, subject only to the Leases and the
Permitted Exceptions.

         24.   Time Periods. If the time period by which any right, option, or
               ------------
election provided under this Agreement must be exercised, or by which any act
required hereunder must be performed, or by which the Closing must be held,
expires on a Saturday, Sunday, or holiday, then such time period shall be
automatically extended through the close of business on the next regularly
scheduled business day.

         25.   Survival of Provisions. All covenants, warranties, and agreements
               ----------------------
set forth in this Agreement shall survive the execution or delivery of any and
all deeds and other documents at any time executed or delivered under, pursuant
to, or by reason of this Agreement, and shall survive the payment of all monies
made under, pursuant to, or by reason of this Agreement for a period of twelve
(12) months from Closing, except with respect to paragraph 19 which shall
survive for twenty-four (24) months.

         26.   Severability. This Agreement is intended to be performed in
               ------------
accordance with, and only to the extent permitted by, all applicable laws,
ordinances, rules, and regulations. If any provision of this Agreement, or the
application thereof to any person or circumstance, shall, for any reason and to
any extent, be invalid or unenforceable, the remainder of this Agreement and the
application of such provision to other persons or circumstances shall not be
affected thereby but rather shall be enforced to the greatest extent permitted
by law.

         27.   Authorization. Purchaser represents to Seller that this Agreement
               -------------
has been duly authorized and executed on behalf of Purchaser and constitutes the
valid and binding agreement of Purchaser, enforceable in accordance with its
terms, and all necessary action on the part of Purchaser to authorize the
transactions herein contemplated has been taken, and no further action is
necessary for such purpose.

         28.   General Provisions. No failure of either party to exercise any
               ------------------
power given hereunder or to insist upon strict compliance with any obligation
specified herein, and no custom or practice at variance with the terms hereof,
shall constitute a waiver of either party's right to
<PAGE>

demand exact compliance with the terms hereof. This Agreement contains the
entire agreement of the parties hereto, and no representations, inducements,
promises, or agreements, oral or otherwise, between the parties not embodied
herein shall be of any force or effect. Any amendment to this Agreement shall
not be binding upon the parties hereto unless such amendment is in writing and
executed by all parties hereto. The provisions of this Agreement shall inure to
the benefit of and be binding upon the parties hereto and their respective
heirs, legal representatives, successors, and assigns. Time is of the essence of
this Agreement. This Agreement may be executed in multiple counterparts, each of
which shall constitute an original, but all of which taken together shall
constitute one and the same agreement. The headings inserted at the beginning of
each paragraph are for convenience only, and do not add to or subtract from the
meaning of the contents of each paragraph. This Agreement shall be construed and
interpreted under the laws of the State of Texas. Except as otherwise provided
herein, all rights, powers, and privileges conferred hereunder upon the parties
shall be cumulative but not restrictive to those given by law. All personal
pronouns used in this Agreement, whether used in the masculine, feminine, or
neuter gender shall include all genders, and all references herein to the
singular shall include the plural and vice versa.

         29.   Effective Date.   The  "effective  date" of this  Agreement
               --------------
shall be deemed to be the date this Agreement is fully executed by both
Purchaser and Seller.

         30.   Duties as Escrow Agent. In performing its duties hereunder,
               ----------------------
Escrow Agent shall not incur any liability to anyone for any damages, losses or
expenses, except for its gross negligence or willful misconduct, and it shall
accordingly not incur any such liability with respect to any action taken or
omitted in good faith upon advice of its counsel or in reliance upon any
instrument, including any written notice or instruction provided for in this
Agreement, not only as to its due execution and the validity and effectiveness
of its provision, but also as to the truth and accuracy of any information
contained therein that Escrow Agent shall in good faith believe to be genuine,
to have been signed or presented by a proper person and to conform to the
provisions of this Agreement. Seller and Purchaser hereby agree to indemnify and
hold harmless Escrow Agent against any and all losses, claims, damages,
liabilities and expenses, including reasonable costs of investigation and legal
fees and disbursements, that may be imposed upon Escrow Agent or incurred by
Escrow Agent in connection with its acceptance or performance of its duties
hereunder as escrow agent, including without limitation, any litigation arising
out of this Agreement. If any dispute shall arise between Seller and Purchaser
sufficient in the discretion of Escrow Agent to justify its doing so, Escrow
Agent shall be entitled to tender into the registry or custody of the clerk of
the Court for the county in which the Property is located or the clerk for the
United States District Court having jurisdiction over the county in which the
Property is located, any or all money (less any sums required to pay Escrow
Agent's attorneys' fees in filing such action), property or documents in its
hands relating to this Agreement, together with such pleadings as it shall deem
appropriate, and thereupon be discharged from all further duties under this
Agreement. Seller and Purchaser shall bear all costs and expenses of any such
legal proceedings.

         31.   Confidentiality. Pending the Closing, Purchaser and Seller agree
               ---------------
to keep the terms of this Agreement, and the existence thereof, strictly
confidential; provided, however, reasonable disclosure may be made to the
parties attorneys, accountants, advisors, lenders, prospective lenders,
<PAGE>

investors, prospective investors and other persons whose involvement in the
transaction requires such disclosure. Purchaser shall not in no event contact
Stone nor inform Stone of the existence of this Agreement.

         32.   (a) This Agreement is subject to and conditioned upon Purchaser's
obtaining a written loan commitment for a loan (the "Acquisition Loan") on or
before the expiration of the Feasability Period TIME BEING OF THE ESSENCE (the
                                                -------------------------
"Loan Contingency Deadline"), from a national banking association or other
lender (the "Bank"), in the amount of $35,970,000.00. All costs with respect to
the Acquisition Loan, its acquisition, negotiation and closing shall be borne by
Seller except that Purchaser shall pay its own legal and entity organizational
fees in connection therewith. In the event the Bank does not issue a loan
commitment ("Loan Commitment") to Purchaser by the Loan Contingency Deadline,
Purchaser shall have the right to terminate this Contract provided that Seller
receives written notice of such termination prior to the Loan Contingency
Deadline, TIME BEING OF THE ESSENCE. Unless extended in writing by Seller, the
          -------------------------
contingency contained in this Section 32 shall expire and be of no force and
effect after the Loan Contingency Deadline.

               (b) Purchaser agrees to make prompt application for, and to
diligently pursue obtaining, a Loan Commitment from the Bank. Purchaser shall
pay for and submit the application for the Acquisition Loan within five (5) days
of the date of this Agreement and provide evidence of such application to
Seller. Purchaser agrees to promptly provide and/or execute such financial and
other information and documents as the Bank may reasonably request in order to
make the Acquisition Loan. Notwithstanding the foregoing, Seller shall reimburse
Purchaser for the fee and other costs paid by Purchaser to the Bank in
connection with the application for a Loan Commitment or in connection with the
Loan Commitment itself in the event that, prior to the expiration of the
Feasability Period, Purchaser certifies to Seller the nature of the
Unsatisfactory Condition and Seller fails to cure the Unsatisfactory Condition
prior to the expiration of the Cure Period.

         33.   Seller's Loan. At Closing, Purchaser shall execute a Purchase
               -------------
Money Note in favor of Seller (the "Purchase Note") in the amount of Three
Million Dollars ($3,000,000.00) (the "Seller's Loan"), which Purchase Note shall
be in the form attached hereto as Exhibit E. Seller's Loan shall bear interest
                                  ---------
at the annual rate of six percent (6%) on the outstanding principal balance of
the Seller's Loan and shall be due in full to Seller on the earlier to occur of
(i) the payment in full of the Acquisition Loan, or (ii) the date that is six
(6) months subsequent to the Closing Date (the earlier date being the "Maturity
Date"). Seller's Loan may be prepaid, in whole or in partial increments of Fifty
Thousand Dollars ($50,000.00), at any time provided that Purchaser gives Seller
written notice of such prepayment at least two weeks prior thereto. Interest
shall be payable in full on the Maturity Date. In addition, the Purchase Note
shall be secured by a deed of trust in the form attached hereto as Exhibit F in
                                                                   ---------
favor of Seller that encumbers the Land and Improvements (the "Deed of Trust"),
which Deed of Trust shall be subordinate to any deed of trust that may secure
the Acquisition Loan


                           [Signature Page Follows]
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and their respective seals to be affixed hereunto as of the day,
month and year first above written.

SELLER:

CARDINAL PARAGON, INC.,
a Texas corporation

By: /s/ Gil J. Besing
   -----------------------------------
        Gil J. Besing, Vice President


PURCHASER:

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

By:      WELLS REAL ESTATE INVESTMENT TRUST, a Maryland real estate investment
         trust, its general partner

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

                                    EXHIBIT A
                                    ---------

                                LAND DESCRIPTION

Being all of the Unrestricted Reserve "I" 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.