Exhibit 10.13

SERVICES AGREEMENT

THIS SERVICES AGREEMENT, is made as of January 1, 2004 (the “Agreement”) by and between MARKWEST ENERGY GP, L.L.C., a Delaware limited liability company (the “General Partner”) and MARKWEST HYDROCARBON, INC., a Delaware corporation (“Manager”).

A.             Pursuant to Section 7.6(c) of the Amended and Restated Limited Partnership Agreement, dated May 24, 2002 (the “Partnership Agreement”) of MarkWest Energy Partners, L.P., a Delaware limited partnership (the “Partnership”), the General Partner is authorized to enter into an agreement with any of its Affiliates (as defined in the Partnership Agreement) to render services to any member of the Partnership Group (as defined in the Partnership Agreement) in the discharge of its duties as general partner of the Partnership.

B.             The General Partner desires to engage the Manager to render day-to-day operational, management, accounting, personnel and related administrative services to the Partnership on the terms and conditions in this Agreement, and the Manager desires to accept such engagement.

NOW THEREFORE, in consideration of the mutual agreements herein set forth, the parties hereto agree as follows:

1.        DEFINITIONS.  The following terms have the meanings assigned them:

(a)            “Agreement” means this Services Agreement.

(b)            “Board of Directors” means the Board of Directors of the General Partner.

(c)            “Code” means the Internal Revenue Code of 1986, as amended.

(d)            “Conflicts Committee” shall have the meaning set forth in the Partnership Agreement.

(e)            “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.

(f)             “Governing Instruments” means, with regard to any entity, the articles of incorporation and bylaws in the case of a corporation, certificate of limited partnership (if applicable) and the partnership agreement in the case of a general or limited partnership or the articles of formation and the operating agreement in the case of a limited liability company.

(g)            “Subsidiary” means any subsidiary of the Partnership.

2.        APPOINTMENT AND DUTIES OF THE MANAGER.

(a)            The General Partner hereby appoints the Manager to manage the assets of the Partnership consistent with the terms of the Partnership Agreement and subject to the further terms and conditions set forth in this Agreement.  The Manager hereby agrees to use its commercially reasonable efforts to perform each of the duties set forth herein. The appointment of the Manager shall be exclusive to the Manager except to the extent that the Manager otherwise agrees, in its sole and absolute discretion, and except to the extent that, the Manager elects to cause the duties of the Manager hereunder to be provided by third parties pursuant to the terms of this Agreement.

(b)            The Manager, in its capacity as manager of the assets and the day-to-day operations of the Partnership, at all times will be subject to the supervision and oversight of the Board of Directors and will have only such functions and authority as the General Partner may delegate to it including, without limitation, the functions and authority identified herein and delegated to the Manager hereby. The Manager will be responsible for the day-to-day operations of the Partnership and will perform (or cause to be performed) such services and activities relating to the assets and operations of the Partnership as may be appropriate, including, without limitation:

(i)             conducting a periodic review of acquisition criteria and parameters for acquisitions, borrowings and operations related thereto and originating acquisition opportunities;

(ii)            investigation, analysis and selection of acquisition opportunities;

(iii)           with respect to prospective acquisitions or dispositions by the Partnership, conducting negotiations with sellers and purchasers and their respective agents, representatives and advisors (including, without limitation, investment bankers);

(iv)           coordinating and managing operations of any joint venture or co-investment interests held by the Partnership and conducting all matters with the joint venture or co-investment partners;

(v)            providing executive and administrative personnel, office space and office services required in rendering services to the Partnership;

(vi)           administering the day-to-day operations of the Partnership and performing and supervising the performance of such other administrative functions necessary in the management of the Partnership as may be agreed upon by the Manager and the Board of Directors, including, without limitation, the collection of revenues and the payment of the Partnership’s debts and obligations and maintenance of appropriate computer services to perform such administrative functions;

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(vii)          communicating on behalf of the Partnership with the holders of any equity or debt securities of the Partnership as required to satisfy the reporting and other requirements of any governmental bodies or agencies or trading markets and to maintain effective relations with such holders;

(viii)         counseling the Partnership regarding the maintenance of its status as a publicly traded partnership for tax purposes and monitoring compliance with the various tests and other rules set out in the Code and Treasury Regulations thereunder related to such status;

(ix)            monitoring the operating performance of the Partnership’s assets and providing periodic reports with respect thereto to the Board of Directors, including comparative information with respect to such operating and performance and budgeted or projected operating results;

(x)             investing and re-investing any moneys and securities of the Partnership (including, without limitation, investing in short-term investments pending investment in operational assets, payment of fees, costs and expenses, or payments of dividends or distributions to partners of the Partnership) and advising the Partnership as to its capital structure and capital raising;

(xi)            assisting the Partnership to retain qualified accountants and legal counsel, as applicable, to assist in developing appropriate accounting procedures, compliance procedures and testing systems with respect to financial reporting obligations and compliance with the provisions of the Code applicable to publicly traded partnerships and to conduct quarterly compliance reviews with respect thereto;

(xii)           causing the Partnership to qualify to do business in all applicable jurisdictions and to obtain and maintain all appropriate licenses;

(xiii)          managing and administering the Partnership’s rights and obligations under all agreements with unaffiliated third parties to which the Partnership is a party or by which the Partnership is bound and monitoring compliance by the Partnership and by such unaffiliated third parties to such agreements with the terms and conditions thereof;

(xiv)         assisting the Partnership in complying with all regulatory requirements applicable to the Partnership in respect of its business activities, including preparing or causing to be prepared all financial statements required under applicable regulations and contractual undertakings and all reports and documents required under the Exchange Act;

(xv)          taking all necessary actions to enable the Partnership to make required tax filings and reports;

(xvi)         handling and resolving all claims, disputes or controversies (including, without limitation, all litigation, arbitration, settlement or other

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proceedings or negotiations) with unaffiliated third parties in which the Partnership may be involved or to which the Partnership may be subject arising out of the Partnership’s day-to-day operations, subject to such limitations or parameters as may be imposed from time to time by the Board of Directors;

(xvii)        using commercially reasonable best efforts to cause expenses incurred by or on behalf of the Partnership to be reasonable or customary and within any budgeted parameters or expense guidelines as may be set by the Board of Directors from time to time;

(xviii)       performing such other services as may be required from time to time for management and other activities relating to the assets of the Partnership as the Board of Directors shall reasonably request or the Manager shall deem appropriate under the particular circumstances; and

(xix)          using commercially reasonable best efforts to cause the Partnership to comply with all applicable laws.

(c)            The Manager may retain, for and on behalf, and at the sole cost and expense, of the Partnership, such services of accountants, legal counsel, appraisers, insurers, brokers, transfer agents, registrars, investment banks, financial advisors, banks and other lenders and others as the Manager deems necessary or advisable in connection with the management and operations of the Partnership.  The Manager shall also have the right to cause any of such services as may be appropriate to be rendered by its employees or affiliates. The Partnership shall pay or reimburse the Manager or its affiliates performing such services for the cost thereof; provided, that such costs and reimbursements are reasonable and no greater than those which would be payable to outside professionals or consultants engaged to perform such services pursuant to agreements negotiated on an arm’s-length basis.

(d)            The Manager shall prepare, or cause to be prepared, at the sole cost and expense of the Partnership, all reports, financial or otherwise, with respect to the Partnership reasonably required by the Board of Directors in order for the Partnership to comply with its Governing Instruments or any other materials required to be filed with any governmental body or agency, and shall prepare, or cause to be prepared, all materials and data necessary to complete such reports and other materials including, without limitation, an annual audit of the Partnership’s books of account by a nationally recognized independent accounting firm selected by the audit committee of the Board of Directors.

(e)            The Manager shall keep a full and complete account of all costs, expenses and expenditures incurred by it in connection with the provision of services under this Agreement.  To the extent that the Manager engages in activities other than the discharge of its responsibilities under this Agreement, the Manager shall separately account for all such costs, expenses and expenditures and the Partnership shall not be billed for such costs, expenses and expenditures.

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(f)             The Manager shall prepare regular reports for the Board of Directors to enable the Board of Directors to review the Partnership’s operations and compliance with the guidelines and policies approved by the Board of Directors.

3.        REPRESENTATIONS AND WARRANTIES OF THE PARTIES

(a)            Each of the General Partner and the Manager hereby represents, warrants and covenants to the other and to the Partnership that the following statements are true and correct as of the date hereof:

(i)             Each of the General Partner and the Manager is duly incorporated, validly existing and in good standing under the laws of the jurisdiction of its formation; each of the General Partner and the Manager has full power and authority to execute and deliver this Agreement and to perform its obligations hereunder;

(ii)            Each of the General Partner and the Manager has duly executed and delivered this Agreement, and this Agreement constitutes the legal, valid and binding obligation of such entity, enforceable against such entity in accordance with its terms (except as such enforcement may be limited by bankruptcy, insolvency or similar laws of general application and by the effect of general principles of equity, regardless of whether considered at law or in equity); and

(iii)           The authorization, execution, delivery and performance of this Agreement by each of the General Partner and the Manager will not result in a breach, default or violation of the organizational documents of such entity.

(b)            If it shall come to the attention of either party to this Agreement that the representations and warranties made by such party in this Section 3 have ceased to be true and correct in all material respects, such party shall promptly notify the other party and the Partnership of such fact.

4.        DEVOTION OF TIME; ADDITIONAL ACTIVITIES.

(a)            The Manager will provide a dedicated management team, including a Chief Executive Officer and such other officers and employees as may be deemed necessary by the Manager, to provide the management services to be provided by the Manager to the Partnership hereunder, the members of which team shall have as their responsibility the management of the Partnership and shall devote such of their time to the management of the Partnership as the Manager or the Board of Directors reasonably deems necessary and appropriate, commensurate with the level of activity of the Partnership from time to time.

(b)            The Manager hereby agrees that neither the Manager nor any entity controlled by or under common control with the Manager shall provide services to any company or other entity whose business, investment policies, guidelines or plan targets is substantially similar to that of the Partnership.  The Partnership shall have the benefit of

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Manager’s best judgment and effort in rendering services and, in furtherance of the foregoing, (i) the Manager shall not undertake activities that, in its judgment, will substantially adversely affect the performance of its obligations under this Agreement and (ii) without the written consent of the Conflicts Committee, the Manager shall not undertake activities that are in competition with any line of business conducted by the Partnership.

(c)            Except to the extent set forth in Section 4(a) or 4(b) above, nothing herein shall prevent the Manager or any of its affiliates or any of the officers and employees of any of the foregoing from engaging in other businesses or from rendering services of any kind to any other person or entity.

(d)            Stockholders, officers, employees and agents of the Manager or affiliates of the Manager may serve as directors, officers, employees, agents, nominees or signatories for the Partnership or any Subsidiary, to the extent permitted by their Governing Instruments, as from time to time amended, or by any resolutions duly adopted by the Board of Directors pursuant to the General Partner’s Governing Instruments.

5.        AGENCY.  The Manager shall act as agent of the Par