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                                                                EXHIBIT 10.68(a)

                         EXECUTIVE EMPLOYMENT AGREEMENT

         This Employment Agreement ("Agreement"), including the attached Exhibit
"A," is entered into between Enron Oil & Gas Company, a Delaware corporation,
having offices at 1400 Smith Street, Houston, Texas 77002 ("Employer"), and Gary
L. Thomas, an individual currently residing at 2392 (E) Bering Drive, Houston,
Texas 77057 ("Employee"), to be effective as of September 1, 1998 (the
"Effective Date").

                                   WITNESSETH:

         WHEREAS, Employer is desirous of employing Employee pursuant to the
terms and conditions and for the consideration set forth in this Agreement, and
Employee is desirous of entering the employ of Employer pursuant to such terms
and conditions and for such consideration.

         NOW, THEREFORE, for and in consideration of the mutual promises,
covenants, and obligations contained herein, Employer and Employee agree as
follows:

ARTICLE 1:  EMPLOYMENT AND DUTIES:

         1.1 Employer agrees to employ Employee, and Employee agrees to be
employed by Employer, beginning as of the Effective Date and continuing until
the date set forth on Exhibit "A" (the "Term"), subject to the terms and
conditions of this Agreement.

         1.2 Employee initially shall be employed in the position set forth on
Exhibit A. Employer may subsequently assign Employee to a different position or
modify Employee's duties and responsibilities, provided that such assignment or
modification is consistent with that of an officer of Employer. Employee agrees
to serve in the assigned position and to perform diligently and to the best of
Employee's abilities the duties and services appertaining to such position as
determined by Employer, as well as such additional or different duties and
services appropriate to such position which Employee from time to time may be
reasonably directed to perform by Employer. Employee shall at all times comply
with and be subject to such policies and procedures as Employer may establish
from time to time.

         1.3 Employee shall, during the period of Employee's employment by
Employer, devote Employee's full business time, energy, and best efforts to the
business and affairs of Employer. Employee may not engage, directly or
indirectly, in any other business, investment, or activity that interferes with
Employee's performance of Employee's duties hereunder, is contrary to the
interests of Employer or Enron Corp. ("Enron"), or requires any significant
portion of Employee's business time.

         1.4 In connection with Employee's employment by Employer, Employer
shall endeavor to provide Employee access to such confidential information
pertaining to the business and services of Employer as is appropriate for
Employee's employment responsibilities. Employer also shall

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endeavor to provide to Employee the opportunity to develop business
relationships with those of Employer's clients and potential clients that are
appropriate for Employee's employment responsibilities.

         1.5 Employee acknowledges and agrees that, at all times during the
employment relationship Employee owes fiduciary duties to Employer, including
but not limited to the fiduciary duties of the highest loyalty, fidelity and
allegiance to act at all times in the best interests of the Employer, to make
full disclosure to Employer of all information that pertains to Employer's
business and interests, to do no act which would injure Employer's business, its
interests, or its reputation, and to refrain from using for Employee's own
benefit or for the benefit of others any information or opportunities pertaining
to Employer's business or interests that are entrusted to Employee or that he
learned while employed by Employer. Employee acknowledges and agrees that upon
termination of the employment relationship, Employee shall continue to refrain
from using for his own benefit or the benefit of others any information or
opportunities pertaining to Employer's business or interests that were entrusted
to Employee during the employment relationship or that he learned while employed
by Employer. Employee agrees that while employed by Employer and thereafter he
shall not knowingly take any action which interferes with the internal
relationships between Employer and its employees or representatives or
interferes with the external relationships between Employer and third parties.

         1.6 It is agreed that any direct or indirect interest in, connection
with, or benefit from any outside activities, particularly commercial
activities, which interest might in any way adversely affect Employer or any of
its affiliates, involves a possible conflict of interest. In keeping with
Employee's fiduciary duties to Employer, Employee agrees that during the
employment relationship Employee shall not knowingly become involved in a
conflict of interest with Employer or its affiliates, or upon discovery thereof,
allow such a conflict to continue. Moreover, Employee agrees that Employee shall
disclose to Employer's President any facts which might involve such a conflict
of interest that has not been approved by Employer's President. Employer and
Employee recognize that it is impossible to provide an exhaustive list of
actions or interests which constitute a "conflict of interest." Moreover,
Employer and Employee recognize there are many borderline situations. In some
instances, full disclosure of facts by the Employee to Employer's President may
be all that is necessary to enable Employer or its affiliates to protect its
interests. In others, if no improper motivation appears to exist and the
interests of Employer or its affiliates have not suffered, prompt elimination of
the outside interest will suffice. In still others, it may be necessary for
Employer to terminate the employment relationship. Employer and Employee agree
that Employer's determination as to whether a conflict of interest exists shall
be conclusive. Employer reserves the right to take such action as, in its
judgment, will end the conflict.

         1.7 Employee understands and acknowledges that the terms and conditions
of this Agreement constitute confidential information. Employee shall keep
confidential the terms of this Agreement and shall not disclose this
confidential information to anyone other than Employee's attorneys, tax
advisors, or as required by law. Employee acknowledges and understands that
disclosure of the terms of this Agreement constitutes a material breach of this
Agreement and could subject Employee to disciplinary action, including without
limitation, termination of employment.

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ARTICLE 2:  COMPENSATION AND BENEFITS:

         2.1 Employee's monthly base salary during the Term shall be not less
than the amount set forth under the heading "Monthly Base Salary" on Exhibit A,
subject to increase at the sole discretion of the Employer, which shall be paid
in semimonthly installments in accordance with Employer's standard payroll
practice. Any calculation to be made under this Agreement with respect to
Employee's Monthly Base Salary shall be made using the then current Monthly Base
Salary in effect at the time of the event for which such calculation is made.

         2.2 While employed by Employer (both during the Term and thereafter),
Employee shall be allowed to participate, on the same basis generally as other
employees of Employer, in all general employee benefit plans and programs,
including improvements or modifications of the same, which on the effective date
or thereafter are made available by Employer to all or substantially all of
Employer's employees. Such benefits, plans, and programs may include, without
limitation, medical, health, and dental care, life insurance, disability
protection, and pension plans. Nothing in this Agreement is to be construed or
interpreted to provide greater rights, participation, coverage, or benefits
under such benefit plans or programs than provided to similarly situated
employees pursuant to the terms and conditions of such benefit plans and
programs.

         2.3 Employer shall not by reason of this Article 2 be obligated to
institute, maintain, or refrain from changing, amending, or discontinuing, any
such incentive compensation or employee benefit program or plan, so long as such
actions are similarly applicable to covered employees generally. Moreover,
unless specifically provided for in a written plan document adopted by the Board
of Directors of either Employer or Enron, none of the benefits or arrangements
described in this Article 2 shall be secured or funded in any way, and each
shall instead constitute an unfunded and unsecured promise to pay money in the
future exclusively from the general assets of Employer.

         2.4 Employer may withhold from any compensation, benefits, or amounts
payable under this Agreement all federal, state, city, or other taxes as may be
required pursuant to any law or governmental regulation or ruling.

ARTICLE 3: TERMINATION PRIOR TO EXPIRATION OF TERM AND EFFECTS OF SUCH
           TERMINATION:

         3.1. Notwithstanding any other provisions of this Agreement, Employer
shall have the right to terminate Employee's employment under this Agreement at
any time prior to the expiration of the Term for any of the following reasons:

         (i)      For "cause" upon the determination by the Employer's Board of
                  Directors or management committee (or, if there is no
                  management committee, the highest applicable level of
                  Employer's management) that "cause" exists for the termination
                  of the employment relationship. As used in this Section
                  3.1(i), the term "cause" shall mean [a] Employee's gross
                  negligence or willful misconduct in the performance of the
                  duties and services required of Employee pursuant to this
                  Agreement; [b] Employee's final conviction of a felony
                  involving moral turpitude; [c] Employee's willful refusal
                  without proper legal reason to perform the duties and
                  responsibilities required of Employee under this Agreement
                  which remains uncorrected for thirty (30) days following
                  written notice to Employee by Employer

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                  of such breach; [d] Employee's involvement in a conflict of
                  interest as referenced in Section 1.6 for which Employer makes
                  a determination to terminate the employment of Employee which
                  remains uncorrected for thirty (30) days following written
                  notice to Employee by Employer of such breach; [e] Employee's
                  willful engagement in conduct that Employee knows or should
                  know is materially injurious to Employer, Enron, or any of
                  their respective subsidiaries; [f] Employee's material breach
                  of any material provision of this Agreement or corporate code
                  or policy which remains uncorrected for thirty (30) days
                  following written notice to Employee by Employer of such
                  breach; or [g] Employee's violation of the Foreign Corrupt
                  Practices Act or other applicable United States law as
                  proscribed by Section 5.1. It is expressly acknowledged and
                  agreed that the decision as to whether "cause" exists for
                  termination of the employment relationship by Employer is
                  delegated to the Employer's management committee (or, if there
                  is no management committee, the highest applicable level of
                  Employer's management) for determination. If Employee
                  disagrees with the decision reached by Employer's management
                  committee (or, if there is no management committee, the
                  highest applicable level of Employer's management), the
                  dispute will be limited to whether Employer's management
                  committee (or, if there is no management committee, the
                  highest applicable level of Employer's management) reached its
                  decision in good faith;

         (ii)     for any other reason whatsoever, with or without cause, in the
                  sole discretion of the management committee (or, if there is
                  no management committee, the highest applicable level of
                  management) of Employer;

         (iii)    upon Employee's death; or

         (iv)     upon Employee's becoming disabled so as to entitle Employee to
                  benefits under Enron's long-term disability plan or, if
                  Employee is not eligible to participate in such plan, then
                  Employee is permanently and totally unable to perform
                  Employee's duties for Employer as a result of any medically
                  determinable physical or mental impairment as supported by a
                  written medical opinion to the foregoing effect by a physician
                  selected by Employer.

The termination of Employee's employment by Employer prior to the expiration of
the Term shall constitute a "Termination for Cause" if made pursuant to Section
3.1(i); the effect of such termination is specified in Section 3.4. The
termination of Employee's employment by Employer prior to the expiration of the
Term shall constitute an "Involuntary Termination" if made pursuant to Section
3.1(ii); the effect of such termination is specified in Section 3.5. The effect
of the employment relationship being terminated pursuant to Section 3.1(iii) as
a result of Employee's death is specified in Section 3.6. The effect of the
employment relationship being terminated pursuant to Section 3.1(iv) as a result
of the Employee becoming incapacitated is specified in Section 3.7.

         3.2 Notwithstanding any other provisions of this Agreement except
Section 8.6, Employee shall have the right to terminate the employment
relationship under this Agreement at any time prior to the expiration of the
Term of employment for any of the following reasons:

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         (i)      a material breach by Employer of any material provision of
                  this Agreement which remains uncorrected for 30 days following
                  written notice of such breach by Employee to Employer; or

         (ii)     for any other reason whatsoever, in the sole discretion of
                  Employee.

The termination of Employee's employment by Employee prior to the expiration of
the Term shall constitute an "Involuntary Termination" if made pursuant to
Section 3.2(i); the effect of such termination is specified in Section 3.5. The
termination of Employee's employment by Employee prior to the expiration of the
Term shall constitute a "Voluntary Termination" if made pursuant to Section
3.2(ii); the effect of such termination is specified in Section 3.3.

         3.3 Upon a "Voluntary Termination" of the employment relationship by
Employee prior to expiration of the Term, Employee shall be entitled to pro rata
salary through the date of such termination, but Employee shall not be entitled
to any individual bonuses or individual incentive compensation not yet paid at
the date of such termination.

         3.4 If Employee's employment hereunder shall be terminated by Employer
for Cause prior to expiration of the Term, Employee shall be entitled to pro
rata salary through the date of such termination, but Employee shall not be
entitled to any individual bonuses or individual incentive compensation not yet
paid at the date of such termination.

         3.5 Upon an Involuntary Termination of the employment relationship by
either Employer or Employee prior to the expiration of the Term, Employee shall
be entitled, in consideration of Employee's continuing obligations hereunder
after such termination (including, without limitation, Employee's
non-competition obligations), to receive the then current Monthly Base Salary as
if Employee's employment (which shall cease on the date of such Involuntary
Termination) had continued for the full Term of this Agreement. If such
Involuntary Termination occurs within two years after a Change of Control, as
defined in Employer's Change of Control Severance Plan, Employee shall receive a
minimum of twenty-four (24) months of the then current Monthly Base Salary.
Employee shall not be under any duty or obligation to seek or accept other
employment following Involuntary Termination and the amounts due Employee
hereunder shall not be reduced or suspended if Employee accepts subsequent
employment. Employee's rights under this Section 3.5 are Employee's sole and
exclusive rights against Employer, Enron, or their affiliates, and Employer's
sole and exclusive liability to Employee under this Agreement, in contract,
tort, or otherwise, for any Involuntary Termination of the employment
relationship. Employee covenants not to sue or lodge any claim, demand or cause
of action against Employer for any sums for Involuntary Termination other than
those sums specified in this Section 3.5. If Employee breaches this covenant,
Employer shall be entitled to recover from Employee all sums expended by
Employer (including costs and attorneys fees) in connection with such suit,
claim, demand or cause of action.

         3.6 Upon termination of the employment relationship as a result of
Employee's death, Employee's heirs, administrators, or legatees shall be
entitled to Employee's pro rata salary through the date of such termination, but
Employee's heirs, administrators, or legatees shall not be entitled to any
individual bonuses or individual incentive compensation not yet paid to Employee
at the date of such termination.

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         3.7 Upon termination of the employment relationship as a result of
Employee's incapacity, Employee shall be entitled to his or her pro rata salary
through the date of such termination, but Employee shall not be entitled to any
individual bonuses or individual incentive compensation not yet paid to Employee
at the date of such termination.

         3.8 In all cases, the compensation and benefits payable to Employee
under this Agreement upon termination of the employment relationship shall be
offset against any amounts to which Employee may otherwise be entitled under any
and all severance plans, and policies of Employer, Enron, or their affiliates.

         3.9 Termination of the employment relationship does not terminate those
obligations imposed by this Agreement which are continuing obligations,
including, without limitation, Employee's obligations under Articles 6 and 7.

         3.10 Upon termination of the employment relationship between Employee
and Employer for any reason, Employee shall be entitled to receive compensation
and benefits earned and accrued by Employee during his/her employment as are
specifically provided in any applicable employee compensation and/or benefit
plan document and any grant or award agreement thereunder.

ARTICLE 4: CONTINUATION OF EMPLOYMENT BEYOND TERM; TERMINATION AND EFFECTS OF
           TERMINATION:

         4.1 Should Employee remain employed by Employer beyond the expiration
of the Term specified on Exhibit "A," such employment shall convert to a
month-to-month relationship terminable at any time by either Employer or
Employee for any reason whatsoever, with or without cause. Upon such termination
of the employment relationship by either Employer or Employee for any reason
whatsoever, all future compensation to which Employee is entitled and all future
benefits for which Employee is eligible shall cease and terminate. Employee
shall be entitled to pro rata salary through the date of such termination, but
Employee shall not be entitled to any individual bonuses or individual incentive
compensation not yet paid at the date of such termination.

ARTICLE 5: UNITED STATES FOREIGN CORRUPT PRACTICES ACT AND
           OTHER LAWS:

         5.1. Employee shall at all times comply with United States laws
applicable to Employee's actions on behalf of Employer, including specifically,
without limitation, the United States Foreign Corrupt Practices Act, generally
codified in 15 USC 78 (FCPA), as the FCPA may hereafter be amended, and/or its
successor statutes. If Employee pleads guilty to or nolo contendere or admits
civil or criminal liability under the FCPA or other applicable United States
law, or if a court finds that Employee has personal civil or criminal liability
under the FCPA or other applicable United States law, or if a court finds that
Employee committed an action resulting in any Enron entity having civil or
criminal liability or responsibility under the FCPA or other applicable United
States law with knowledge of the activities giving rise to such liability or
knowledge of facts from which Employee should have reasonably inferred the
activities giving rise to liability had occurred or were likely to occur, such
action or finding shall constitute "cause" for termination under this Agreement

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unless Employer's management committee (or, if there is no management committee,
the highest applicable level of Employer's management) determines that the
actions found to be in violation of the FCPA or other applicable United States
law were taken in good faith and in compliance with all applicable policies of
Employer and Enron.

ARTICLE 6: OWNERSHIP AND PROTECTION OF INFORMATION; COPYRIGHTS:

         6.1 All information, ideas, concepts, improvements, discoveries, and
inventions, whether patentable or not, which are conceived, made, developed or
acquired by Employee, individually or in conjunction with others, during
Employee's employment by Employer (whether during business hours or otherwise
and whether on Employer's premises or otherwise) which relate to Employer's
business, products or services (including, without limitation, all such
information relating to corporate opportunities, research, financial and sales
data, pricing and trading terms, evaluations, opinions, interpretations,
acquisition prospects, the identity of customers or their requirements, the
identity of key contacts within the customer's organizations or within the
organization of acquisition prospects, or marketing and merchandising
techniques, prospective names, and marks) shall be disclosed to Employer and are
and shall be the sole and exclusive property of Employer. Moreover, all
drawings, memoranda, notes, records, files, correspondence, drawings, manuals,
models, specifications, computer programs, maps and all other writings or
materials of any type embodying any of such information, ideas, concepts,
improvements, discoveries, and inventions are and shall be the sole and
exclusive property of Employer.

         6.2 Employee acknowledges that the business of Employer, Enron, and
their affiliates is highly competitive and that their strategies, methods,
books, records, and documents, their technical information concerning their
products, equipment, services, and processes, procurement procedures and pricing
techniques, the names of and other information (such as credit and financial
data) concerning their customers and business affiliates, all comprise
confidential business information and trade secrets which are valuable, special,
and unique assets which Employer, Enron, or their affiliates use in their
business to obtain a competitive advantage over their competitors. Employee
further acknowledges that protection of such confidential business information
and trade secrets against unauthorized disclosure and use is of critical
importance to Employer, Enron, and their affiliates in maintaining their
competitive position. Employee hereby agrees that Employee will not, at any time
during or after his or her employment by Employer, make any unauthorized
disclosure of any confidential business information or trade secrets of
Employer, Enron, or their affiliates, or make any use thereof, except in the
carrying out of his or her employment responsibilities hereunder. Enron and its
affiliates shall be third party beneficiaries of Employee's obligations under
this Section. As a result of Employee's employment by Employer, Employee may
also from time to time have access to, or knowledge of, confidential business
information or trade secrets of third parties, such as customers, suppliers,
partners, joint venturers, and the like, of Employer, Enron, and their
affiliates. Employee also agrees to preserve and protect the confidentiality of
such third party confidential information and trade secrets to the same extent,
and on the same basis, as Employer's confidential business information and trade
secrets. Employee acknowledges that money damages would not be sufficient remedy
for any breach of this Article 6 by Employee, and Employer shall be entitled to
enforce the provisions of this Article 6 by terminating any payments then owing
to Employee under this Agreement and/or to specific performance and injunctive
relief as remedies for such breach or any threatened breach. Such remedies shall
not be deemed the exclusive remedies for

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a breach of this Article 6, but shall be in addition to all remedies available
at law or in equity to Employer, including the recovery of damages from Employee
and his or her agents involved in such breach.

         6.3 All written materials, records, and other documents made by, or
coming into the possession of, Employee during the period of Employee's
employment by Employer which contain or disclose confidential business
information or trade secrets of Employer, Enron, or their affiliates shall be
and remain the property of Employer, Enron, or their affiliates, as the case may
be. Upon termination of Employee's employment by Employer, for any reason,
Employee promptly shall deliver the same, and all copies thereof, to Employer.

         6.4 If, during Employee's employment by Employer, Employee creates any
original work of authorship fixed in any tangible medium of expression which is
the subject matter of copyright (such as videotapes, written presentations on
acquisitions, computer programs, drawings, maps, architectural renditions,
models, manuals, brochures, or the like) relating to Employer's business,
products, or services, whether such work is created solely by Employee or
jointly with others (whether during business hours or otherwise and whether on
Employer's premises or otherwise), Employee shall disclose such work to
Employer. Employer shall be deemed the author of such work if the work is
prepared by Employee in the scope of his or her employment; or, if the work is
not prepared by Employee within the scope of his or her employment but is
specially ordered by Employer as a contribution to a collective work, as a part
of a motion picture or other audiovisual work, as a translation, as a
supplementary work, as a compilation, or as an instructional text, then the work
shall be considered to be work made for hire and Employer shall be the author of
the work. If such work is neither prepared by the Employee within the scope of
his or her employment nor a work specially ordered and is deemed to be a work
made for hire, then Employee hereby agrees to assign, and by these presents does
assign, to Employer all of Employee's worldwide right, title, and interest in
and to such work and all rights of copyright therein.

         6.5 Both during the period of Employee's employment by Employer and
thereafter, Employee shall assist Employer and its nominee, at any time, in the
protection of Employer's worldwide right, title, and interest in and to
information, ideas, concepts, improvements, discoveries, and inventions, and its
copyrighted works, including without limitation, the execution of all formal
assignment documents requested by Employer or its nominee and the execution of
all lawful oaths and applications for applications for patents and registration
of copyright in the United States and foreign countries.

ARTICLE 7: POST-EMPLOYMENT NON-COMPETITION OBLIGATIONS:

         7.1 As part of the consideration for the compensation and benefits to
be paid to Employee hereunder, in keeping with Employee's duties as a fiduciary
and in order to protect Employer's interests in the confidential information of
Employer and the business relationships developed by Employee with the clients
and potential clients of Employer, and as an additional incentive for Employer
to enter into this Agreement, Employer and Employee agree to the non-competition
provisions of this Article 7. Employee agrees that during the period of
Employee's non-competition obligations hereunder, Employee will not, directly or
indirectly for Employee or for others, in any geographic area or market where
Employer or Enron or any of their affiliated

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companies are conducting any business as of the date of termination of the
employment relationship or have during the previous twelve months conducted any
business:

         (i) engage in any business competitive with the business conducted by
Employer;

         (ii) render advice or services to, or otherwise assist, any other
person, association, or entity who is engaged, directly or indirectly, in any
business competitive with the business conducted by Employer;

         (iii) induce any employee of Employer or Enron or any of their
affiliates to terminate his or her employment with Employer, Enron, or their
affiliates, or hire or assist in the hiring of any such employee by person,
association, or entity not affiliated with Enron.

These non-competition obligations shall extend until the earlier of (a)
expiration of the Term or (b) one year after termination of the employment
relationship.

         7.2 Employee understands that the foregoing restrictions may limit his
or her ability to engage in certain businesses anywhere in the world during the
period provided for above, but acknowledges that Employee will receive
sufficiently high remuneration and other benefits (e.g., the right to receive
compensation under Section 3.5 for the remainder of the Term upon Involuntary
Termination) under this Agreement to justify such restriction. Employee
acknowledges that money damages would not be sufficient remedy for any breach of
this Article 7 by Employee, and Employer shall be entitled to enforce the
provisions of this Article 7 by terminating any payments then owing to Employee
under this Agreement and/or to specific performance and injunctive relief as
remedies for such breach or any threatened breach. Such remedies shall not be
deemed the exclusive remedies for a breach of this Article 7, but shall be in
addition to all remedies available at law or in equity to Employer, including,
without limitation, the recovery of damages from Employee and his or her agents
involved in such breach.

         7.3 It is expressly understood and agreed that Employer and Employee
consider the restrictions contained in this Article 7 to be reasonable and
necessary to protect the proprietary information of Employer. Nevertheless, if
any of the aforesaid restrictions are found by a court having jurisdiction to be
unreasonable, or overly broad as to geographic area or time, or otherwise
unenforceable, the parties intend for the restrictions therein set forth to be
modified by such courts so as to be reasonable and enforceable and, as so
modified by the court, to be fully enforced.

ARTICLE 8: MISCELLANEOUS:

         8.1 For purposes of this Agreement the terms "affiliates" or
"affiliated" means an entity who directly, or indirectly through one or more
intermediaries, controls, is controlled by, or is under common control with
Enron or Employer.

         8.2 Employee shall refrain, both during the employment relationship and
after the employment relationship terminates, from publishing any oral or
written statements about Employer, Enron, any of their respective subsidiaries
or affiliates, or any of such entities' officers, employees, agents or
representatives that are slanderous, libelous, or defamatory; or that disclose
private or

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confidential information about Employer, Enron, any of their respective
subsidiaries or affiliates, or any of such entities' business affairs, officers,
employees, agents, or representatives; or that constitute an intrusion into the
seclusion or private lives of Employer, Enron, any of their respective
subsidiaries or affiliates, or such entities' officers, employees, agents, or
representatives; or that give rise to unreasonable publicity about the private
lives of Employer, Enron, any of their respective subsidiaries or affiliates, or
any of such entities' officers, employees, agents, or representatives; or that
place Employer, Enron, any of their respective subsidiaries or affiliates, or
any of such entities' or its officers, employees, agents, or representatives in
a false light before the public; or that constitute a misappropriation of the
name or likeness of Employer, Enron, any of their respective subsidiaries or
affiliates, or any of such entities' or its officers, employees, agents, or
representatives. A violation or threatened violation of this prohibition may be
enjoined by the courts. The rights afforded the Enron entities and affiliates
under this provision are in addition to any and all rights and remedies
otherwise afforded by law.

         8.3 For purposes of this Agreement, notices and all other
communications provided for herein shall be in writing and shall be deemed to
have been duly given when personally delivered or when mailed by United States
registered or certified mail, return receipt requested, postage prepaid,
addressed as follows:

         If to Employer:

                  Enron Oil & Gas Company
                  1400 Smith Street
                  Houston, Texas 77002
                  Attention:  Corporate Secretary

         If to Employee, to the address shown on the first page hereof.

Either Employer or Employee may furnish a change of address to the other in
writing in accordance herewith, except that notices of changes of address shall
be effective only upon receipt.

         8.4 This Agreement shall be governed in all respects by the laws of the
State of Texas, excluding any conflict-of-law rule or principle that might refer
the construction of the Agreement to the laws of another State or country.

         8.5 No failure by either party hereto at any time to give notice of any
breach by the other party of, or to require compliance with, any condition or
provision of this Agreement shall be deemed a waiver of similar or dissimilar
provisions or conditions at the same or at any prior or subsequent time.

         8.6 If a dispute arises out of or related to this Agreement, other than
a dispute regarding Employee's obligations under Article 6, or Article 7, and if
the dispute cannot be settled through direct discussions, then Employer and
Employee agree to first endeavor to settle the dispute in an amicable manner by
mediation, before having recourse to any other proceeding or forum.

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         8.7 Each of Employer and Employee is a citizen of the State of Texas.
Employer's principal place of business is in Houston, Harris County, Texas.
Employee resides in Harris County, Texas. This Agreement was negotiated and
signed in Houston, Texas. This Agreement shall be performed in Houston, Texas.
Any litigation that may be brought by either Employer or Employee involving the
enforcement of this Agreement or the rights, duties, or obligations of this
Agreement, shall be brought exclusively in the State or federal courts sitting
in Houston, Harris County, Texas. In the event that service of process cannot be
effected upon a party, each party hereby irrevocably appoints the Secretary of
State for the State of Texas as its or his agent for service of process to
receive the summons and other pleadings in connection with any such litigation.

         8.8 It is a desire and intent of the parties that the terms,
provisions, covenants, and remedies contained in this Agreement shall be
enforceable to the fullest extent permitted by law. If any such term, provision,
covenant, or remedy of this Agreement or the application thereof to any person,
association, or entity or circumstances shall, to any extent, be construed to be
invalid or unenforceable in whole or in part, then such term, provision,
covenant, or remedy shall be construed in a manner so as to permit its
enforceability under the applicable law to the fullest extent permitted by law.
In any case, the remaining provisions of this Agreement or the application
thereof to any person, association, or entity or circumstances other than those
to which they have been held invalid or unenforceable, shall remain in full
force and effect.

         8.9 This Agreement shall be binding upon and inure to the benefit of
Employer and any other person, association, or entity which may hereafter
acquire or succeed to all or substantially all of the business or assets of
Employer by any means whether direct or indirect, by purchase, merger,
consolidation, or otherwise. Employee's rights and obligations under Agreement
hereof are personal and such rights, benefits, and obligations of Employee shall
not be voluntarily or involuntarily assigned, alienated, or transferred, whether
by operation of law or otherwise, without the prior written consent of Employer.

         8.10 There exist other agreements between Employer and Employee
relating to the employment relationship between them, e.g., the agreement with
respect to company policies contained in Employer's Conduct of Business Affairs
booklet and agreements with respect to compensation and benefit plans. This
Agreement replaces and merges previous agreements and discussions pertaining to
the following subject matters covered herein: the nature of Employee's
employment relationship with Employer and the term and termination of such
relationship. This Agreement constitutes the entire agreement of the parties
with regard to such subject matters, and contains all of the covenants,
promises, representations, warranties, and agreements between the parties with
respect such subject matters. Each party to this Agreement acknowledges that no
representation, inducement, promise, or agreement, oral or written, has been
made by either party with respect to such subject matters, which is not embodied
herein, and that no agreement, statement, or promise relating to the employment
of Employee by Employer that is not contained in this Agreement shall be valid
or binding. Any modification of this Agreement will be effective only if it is
in writing and signed by each party whose rights hereunder are affected thereby,
provided that any such modification must be authorized or approved by the Board
of Directors of Employer.

                                       11
<PAGE>   12

         IN WITNESS WHEREOF, Employer and Employee have duly executed this
Agreement in multiple originals to be effective on the date first stated above.

                                    ENRON OIL & GAS COMPANY

                                    By:        /s/ PATRICIA EDWARDS
                                       -----------------------------------------
                                    Name: Patricia Edwards
                                    Title: V.P. Human Resources & Administration
                                    This 29th day of September, 1998

                                    GARY L. THOMAS

                                               /s/ GARY L. THOMAS
                                    --------------------------------------------
                                    This 25 day of September, 1998

                                       12
<PAGE>   13

                                 EXHIBIT "A" TO
                         EXECUTIVE EMPLOYMENT AGREEMENT
               BETWEEN ENRON OIL & GAS COMPANY AND GARY L. THOMAS

Employee Name:            Gary L. Thomas

Term:                     September 1, 1998 through August 31, 2001

Position:                 Executive Vice President, North American Operations

Location:                 Houston, Texas

Reporting Relationship:   Reports to Mark G. Papa, President and Chief Executive
                          Officer

Monthly Base Salary:      Twenty thousand eight hundred thirty-five dollars
                          ($20,835)

Bonus:                    Employee shall be eligible to participate in
                          Employer's annual bonus program, under which bonuses
                          may be paid in a combination of cash, stock options,
                          and/or phantom stock units, as determined by the
                          Compensation Committee of Employer's Board of
                          Directors.

Long-Term Incentives:     Employee shall be eligible to receive long-term
                          incentive grants consistent with similarly situated
                          executives of Employer.

Stock Option Grant:       Employee shall receive a grant of 125,000 stock
                          options, effective September 8, 1998, vesting 20% on
                          the Grant Date and 20% on each of the first four
                          anniversaries of the Grant Date, as evidenced by an
                          Award Agreement, upon execution of this Agreement.

                                    ENRON OIL & GAS COMPANY

                                    By:      /s/ PATRICIA EDWARDS
                                       -----------------------------------------
                                    Name: Patricia Edwards
                                    Title: V.P. Human Resources & Administration
                                    This 29th day of September, 1998

                                    GARY L. THOMAS

                                             /s/ GARY L. THOMAS
                                    --------------------------------------------
                                    This 25 day of September, 1998

                                       13<PAGE>   1
                                                                EXHIBIT 10.68(b)

                FIRST AMENDMENT TO EXECUTIVE EMPLOYMENT AGREEMENT

         This Agreement, entered into on this 12 of March, 1999, and made
effective as of February 1, 1999, by and between ENRON OIL & GAS COMPANY
("Company" or "Employer") and GARY L. THOMAS ("Employee") is an amendment to
that certain Employment Agreement made effective as of September 1, 1998 (the
"Employment Agreement").

         WHEREAS, the parties desire to amend the Employment Agreement as
provided herein;

         NOW, THEREFORE, in consideration thereof and of the mutual covenants
contained herein, the parties agree as follows:

         1.       Article 3, Section 3.5 of the Employment Agreement is hereby
                  deleted in its entirety and the following is substituted
                  therefor:

                  "3.5 Upon an Involuntary Termination of the employment
                  relationship by either Employer or Employee prior to the
                  expiration of the Term, Employee shall be entitled, in
                  consideration of Employee's continuing obligations hereunder
                  after such termination (including, without limitation,
                  Employee's non-competition obligations), to receive the then
                  current Monthly Base Salary as if Employee's employment (which
                  shall cease on the date of such Involuntary Termination) had
                  continued for the full Term of this Agreement. Notwithstanding
                  any other provisions of this Agreement, a termination of the
                  employment relationship by either the Employer or Employee
                  which meets the definition of Involuntary Termination under
                  the Company's Change of Control Severance Plan shall
                  constitute an Involuntary Termination under this Agreement. In
                  the event of such Involuntary Termination which entitles
                  Employee to severance benefits under said Plan, but for the
                  following severance payment by the Company to the Employee,
                  Employee shall receive from the Company a severance benefit
                  under this Agreement equal to the sum of Employee's then
                  current Monthly Base Salary times 12 times 2.99 plus two times
                  the Employee's annual bonus target award under the Company's
                  annual bonus program for the year in which the Change of
                  Control Date occurs. Employee's severance benefit payable
                  under said Plan, if any, shall be determined according to the
                  provisions thereof. Employee shall not be under any duty or
                  obligation to seek or accept other employment following
                  Involuntary Termination and the amounts due Employee hereunder
                  shall not be reduced or suspended if Employee

<PAGE>   2

                  accepts subsequent employment. Employee's rights under this
                  Section 3.5 are Employee's sole and exclusive rights against
                  Employer, Enron, or their affiliates, and Employer's sole and
                  exclusive liability to Employee under this Agreement, in
                  contract, tort, or otherwise, for any Involuntary Termination
                  of the employment relationship. Employee covenants not to sue
                  or lodge any claim, demand or cause of action against Employer
                  for any sums for Involuntary Termination other than those sums
                  specified in this Section 3.5. If Employee breaches this
                  covenant, Employer shall be entitled to recover from Employee
                  all sums expended by Employer (including costs and attorneys
                  fees) in connection with such suit, claim, demand or cause of
                  action."

         2.       The following sentence shall be inserted at the end of Article
                  7, Section 7.1:

                  "However, upon an Involuntary Termination as defined in the
                  Company's Change of Control Severance Plan, which entitles
                  Employee to severance benefits under said Plan, these
                  non-competition obligations shall expire immediately and have
                  no further force and effect."

         3.       The following new Article 9 shall be inserted at the end of
                  the Employment Agreement:

                  "ARTICLE 9:  U.S. EXCISE TAX INDEMNIFICATION

                        9.1 Indemnification. In the event it shall be determined
                  that any payment or distribution by the Company to or for the
                  benefit of Employee (whether paid or payable or distributed or
                  distributable pursuant to the terms of this Agreement, the
                  Company's Change of Control Severance Plan or otherwise, but
                  determined without regard to any additional payments required
                  under this Article 9) (a "Payment") would be subject to the
                  excise tax imposed by Section 4999 of the United States
                  Internal Revenue Code of 1986, as amended (the "Code"), or any
                  interest or penalties are incurred by Employee with respect to
                  such excise tax (such excise tax, together with any such
                  interest and penalties, are hereinafter collectively referred
                  to as the "Excise Tax"), then Employee shall be entitled to
                  receive an additional payment (a "Gross-Up Payment") in an
                  amount such that after payment by Employee of all taxes
                  (including any interest or penalties imposed with respect to
                  such taxes), including, without limitation, any income and
                  employment taxes (and any interest and penalties imposed with
                  respect thereto) and Excise Tax imposed upon the Gross-Up
                  Payment, Employee retains an amount of the Gross-Up Payment
                  equal to the Excise Tax imposed upon the Payments.

                        9.2 Determination of Amount. Subject to the provisions
                  of Section 9.3, all determinations required to be made under
                  this Article 9,

<PAGE>   3

                  including whether and when a Gross-Up Payment is required and
                  the amount of such Gross-Up Payment and the assumptions to be
                  utilized in arriving at such determination, shall be made by a
                  public accounting firm chosen by the Company (the "Accounting
                  Firm") which shall provide detailed supporting calculations
                  both to the Company and Employee if requested by either the
                  Company or Employee. All fees and expenses of the Accounting
                  Firm shall be borne solely by the Company. Any determination
                  by the Accounting Firm shall be binding upon the Company and
                  Employee. As a result of the uncertainty in the application of
                  Section 4999 of the Code at the time of the initial
                  determination by the Accounting Firm hereunder, it is possible
                  that Gross-Up Payments which will not have been made by the
                  Company should have been made ("Underpayment"), consistent
                  with the calculations required to be made hereunder. In the
                  event that the Company exhausts its remedies pursuant to
                  Section 9.3 and Employee thereafter is required to make a
                  payment of any additional Excise Tax, the Accounting Firm
                  shall determine the amount of the Underpayment that has
                  occurred and any such Underpayment shall be promptly paid by
                  the Company to or for the benefit of Employee.

                        9.3 Contest of Claims. If the Company elects to contest
                  a claim by the Internal Revenue Service that Excise Tax is due
                  from Employee, Employee shall cooperate fully with the Company
                  in order to effectively contest such claim, including, but not
                  limited to providing information reasonably requested by the
                  Company relating to such claim, accepting legal representation
                  with respect to such claim by an attorney reasonably selected
                  by the Company and permitting the Company to participate in
                  any proceedings relating to such claim. The Company shall bear
                  and pay directly all costs and expenses (including additional
                  interest and penalties) incurred in connection with such
                  contest and shall indemnify and hold Employee harmless, on an
                  after-tax basis, for any Excise Tax or other tax (including
                  interest and penalties with respect thereto) imposed as a
                  result of such representation and payment of costs and
                  expenses.

                        9.4 Advances and Refunds. If the Company directs
                  Employee to pay a claim by the Internal Revenue Service and
                  sue for a refund, the Company shall advance the amount of such
                  payment to Employee on an interest-free basis and shall
                  indemnify and hold Employee harmless, on an after-tax basis,
                  from any Excise Tax or income tax (including interest or
                  penalties with respect thereto) imposed with respect to such
                  advance or with respect to any imputed income with respect to
                  such advance. If, after the receipt by

<PAGE>   4

                  Employee of an amount advanced by the Company pursuant to this
                  Section 9.4, Employee becomes entitled to receive, and
                  receives, any refund with respect to such claim, Employee
                  shall promptly pay to the Company the amount of such refund
                  (together with any interest paid or credited thereon after
                  taxes applicable thereto). If, after the receipt by Employee
                  of an amount advanced by the Company pursuant to this Section
                  9.4, a determination is made that Employee is not entitled to
                  any refund with respect to such claim, then such advance shall
                  not be required to be repaid and the amount of such advance
                  shall offset, to the extent thereof, the amount of Gross-Up
                  Payment required to be paid."

         This Agreement is the First Amendment to the Employment Agreement, and
the parties agree that all other terms, conditions and stipulations contained in
the Employment Agreement, and any amendments thereto, shall remain in full force
and effect and without any change or modification, except as provided herein.

         IN WITNESS WHEREOF, the parties have duly executed this Agreement as of
the date first above written.

                                   ENRON OIL & GAS COMPANY

                                   By: /s/ PATRICIA EDWARDS
                                      --------------------------------------
                                   Name: Patricia Edwards
                                   Title: V.P. Human Resources & Administration
                                   This 15th day of March, 1999

                                   GARY L. THOMAS

                                       /s/ GARY L. THOMAS
                                   -----------------------------------------
                                   This 12 day of March, 1999

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