EXHIBIT 10.3.28618-1           FIRST AMENDMENT TO THEPRIMEENERGY CORPORATION EMPLOYEES 401(K) SAVINGS PLANThis FIRST AMENDMENT to the PrimeEnergy Corporation Employees 401(k) Savings Plan is executed byPrimeEnergy Corporation, EOWS Midland Company, Eastern Oil Well Service Company, Prime OperatingCompany, Southwest Oilfield Construction Company, PrimeEnergy Management Corporation, and PrimeOffshore LLC the Employers.The purpose of this Amendment is to reflect the merger of Prime Offshore LLC Plan, to add SafeHarbor plan provisions, to add an Adopting Employer, to add the Automatic Enrollment provision, tochange the eligibility requirements, entry date, increase salary deferral limit, and to changeIn-Service Withdrawals of Employer contributions. Furthermore, it is the Company’s intention tograndfather the eligibility provision of 6 months of service for those employees employed on orbefore December 31, 2006.RESOLVED, that Adoption Agreement Section B(2), Plan Information — Effective Date, be amended by***adding the election of Item B(2)(d), This is a merger of two previously established qualified plansknown as PrimeEnergy Corporation Employees 401(k) Savings Plan and Prime Offshore LLC 401(k) Planoriginally effective January 1, 1989 and January 1, 2002, respectively. This amendment andrestatement plan shall be effective as of January 1, 2007.***FURTHER RESOLVED, that Adoption Agreement Section C(l), Eligibility Requirements — EligibleEmployees (Plan Section 1.18), be amended by changing Item C(l)(b)(7), The following are excluded:Other: all except employees of PrimeEnergy Corp., PrimeEnergy Management Corp., Prime OperatingCo., Eastern Oil Well Service Company, Southwest Oilfield Construction Company, and EOWS MidlandCompany, to Item C(l)(b)(7), The following are excluded: Other: all except employees of PrimeEnergy Corp., PrimeEnergy Management Corp., Prime Operating Co., Eastern Oil Well Service Company,Southwest Oilfield Construction Company, EOWS Midland Company and ***Prime Offshore LLC.***FURTHER RESOLVED, that Adoption Agreement Section C(2), Eligibility Requirements — AffiliatedEmployers (Plan Section 1.6), be amended by **adding to the List of Participating Employers asfollows:**Item C(2)(b) ***Prime Offshore LLC, Taxpayer Identification Number: 76-0688905***FURTHER RESOLVED, that Adoption Agreement Section C(3), Eligibility Requirements — Conditions ofEligibility (Plan Section 3.1), be amended by **changing the election** of Item C(3)(b)(2), AnyEligible Employee will be eligible to participate in the Plan upon completion of 1/2 Year ofService or Period of Service, ***to Item C(3)(b)(3), Any Eligible Employee will be eligible toparticipate in the Plan upon completion of 1 Year of Service or Period of Service.***
1

 
8618-1           FURTHER RESOLVED, that Adoption Agreement Section C(4), Eligibility Requirements — Entry Date(Effective Date of Participation) (Plan Section 3.2), be amended by **changing the election**of ItemC(4)(b), An Eligible Employee who has satisfied the eligibility requirements will become aParticipant for all purposes of the Plan the first day of the month coinciding with or nextfollowing the date on which such requirements are satisfied, ***to Item G(4)(d), An Eligible Employeewho has satisfied the eligibility requirements will become a Participant for all purposes of thePlan the earlier of the first day of the seventh month or the first day of the Plan Year coincidingwith or next following the date on which such requirements are satisfied.***FURTHER RESOLVED, that Adoption Agreement Section D(l), Service — Recognition of Service withPredecessor Employer (Plan Sections 1.61 and 1.91), be amended by **changing the election**of ItemD(l)(a), No service with a predecessor employer shall be recognized, ***to Item D(1)(b)(1), Servicewith Prime Offshore, LLC will be recognized with no limitations.***FURTHER RESOLVED, that Adoption Agreement Section G(l), Contributions and Allocations — Salary ReductionArrangement — Elective Deferrals (Plan Section 12.2), be amended by**changing the election**of Item G(1)(b), Each Participant may elect to have Compensationdeferred by up to 15%, ***to Item G(1)(a), Each Participant may elect to have Compensationdeferred by up to the maximum percentage allowable not to exceed the limits of Code Section401(k), 402(g), 404 and 415.***FURTHER RESOLVED, that Adoption Agreement Section G(1), Contributions and Allocations — AutomaticEnrollment, be amended by **changing the election**of Item G(1)(o), ShallParticipants who do not affirmatively elect to receive cash or have a specified amountcontributed to the Plan automatically have Compensation reduced? No., ***to Item G(1)(p), ShallParticipants who do not affirmatively elect to receive the cash or have a specified amountcontributed to the Plan automatically have Compensation reduced? Yes, by 4% ofCompensation, provided that such enrollment is permissible under the laws of the state inwhich the Participants are employed in.***FURTHER RESOLVED, that Adoption Agreement Section G(2), Contribution and Allocations — 401(k) SafeHarbor Plan Provisions (Plan Section 12.8), be amended by **changing the election**of Item G(2)(a),Will the ADP and/or ACP test safe harbor provisions be used? No., ***to Item G(2)(b), Will the ADPand/or ACP test safe harbor provisions be used? Yes, but only the ADP Test Safe Harbor provisionswill be used.***FURTHER RESOLVED, that Adoption Agreement Section G(2), Contribution and Allocations — 401(k) SafeHarbor Plan Provisions (Plan Section 12.8) — ADP Test Safe Harbor Contribution,be amended by ***adding the election of Item G(2)(d)(2)(a), The Employer will make anEnhanced Matching Contribution. The Employer will make Matching Contributions to theaccount of each “Eligible Participant” in an amount equal to the sum of 100% of theParticipant’s Elective Deferrals that do not exceed 4% of the Participant’s Compensation.***and by **further electing:*****Item G(2)(d)(3)(b), The safe harbor matching contribution will be made each payroll period.***
2

 
8618-1           ***Item G(2)(f)(5), For purposes of the ADP Test Safe Harbor contribution, the term “EligibleParticipant” means any Participant who is eligible to make Elective Deferrals. The ADP and/or ACPTest Safe Harbor provisions are effective for the Plan Year beginning January 1, 2007.***FURTHER RESOLVED, that Adoption Agreement Section G(3), Contribution and Allocations — Formula forDetermining Employer Matching Contributions (Plan Section 12.1 (a)(2)), beamended **by removing the election**of Item G(3)(b)(1) & (5), The Employer may makematching contributions equal to a discretionary percentage, to be determined by the Employer, ofthe Participant’s Elective Deferrals, AND, in determining the matching contribution, adiscretionary percentage of a Participant’s Compensation or a discretionary dollar amount, thepercentage or dollar amount to be determined by the Employer on a uniform basis to allParticipants will be matched.and by **further removing:**G(3)(g), Matching contributions will be determined based on Elective Deferrals made eachpayroll period.G(3)(j), There is no dollar limit imposed on the matching contribution made on behalf of anyParticipant for any Plan Year.G(3)(l), Matching contributions will be made on behalf of all Participants.G(3)(n), The matching contributions will not be qualified matching contributions.FURTHER RESOLVED, that Adoption Agreement Section G(4), Contribution and Allocations — Requirementsfor the allocation of Matching Contributions, be amended **by removing the election**ofItem G(4)(b), No service requirement for Participants who are actively employedat the end of the Plan Year.and by **further removing:**G(4)(g), Participants who are not actively employed at the end of the Plan Year willshare in such allocations, regardless of service.FURTHER RESOLVED, that Adoption Agreement Section H(7), Distributions — In-Service Distributions(Plan Section 6.10), be amended by **changing the election**of Item H(7)(b)(2)(a), In-servicedistributions may be made to a Participant who has not separated from service from Participant’saccounts attributable to Employer matching and profit sharing contributions provided theParticipant has attained age 701/2*,****to Item H(7)(b)(2)(a), In-service distributions may be made toa Participant who has not separated from service from Participant’s accounts attributable toEmployer matching and profit sharing contributions provided the Participant has attained age 591/2.***
3

 
FURTHER RESOLVED, that Adoption Agreement Section I(2), Nondiscrimination Testing — ADP and ACPTests (Plan Sections 12.4 and 12.6), be amended by **changing the election**of Item I(2)(b), PriorYear Testing Election: The prior year ratio will be used for the ADP and ACP tests, ***to ItemI(2)(a),******N/A.******This plan satisfies the ADP and ACP Test Safe Harbor rules by making a Basic MatchingContribution or an Enhanced Matching Contribution for all Plan Years beginning on or after theEffective Date of the Plan, or in the case of an amendment and restatement, for all Plan Years towhich the amendment and restatement relates.***FURTHER RESOLVED, that the effective date of this Amendment shall be January 1, 2007.IN WITNESS WHEREOF, the Employer has caused this Amendment to be executed this 29 day of November, 2006.     PrimeEnergy Corporation       By: /s/ Virginia Crowe Forese     For the Employer       EOWS Midland Company       By: /s/ Virginia Crowe Forese     For the Employer       Eastern Oil Well Service Company       By: /s/ Virginia Crowe Forese     For the Employer       Prime Operating Company       By: /s/ Virginia Crowe Forese     For the Employer       Southwest Oilfield Construction Company       By: /s/ Virginia Crowe Forese     For the Employer       PrimeEnergy Management Corporation       By: /s/ Virginia Crowe Forese     For the Employer       Prime Offshore LLC       By: /s/ Virginia Crowe Forese     For the Employer  
4