Exhibit 99.2

MarkWest Energy Partners Announces $150 Million Credit Facility Increase

DENVER—December 29—MarkWest Energy Partners, L.P. (NYSE: MWE) announced today the execution of a $150 million increase to its senior secured revolving credit facility, increasing total borrowing capacity to $900 million.  The revolving credit facility, which matures in September 2016, is supported by a syndicate of 18 banks led by Wells Fargo Securities, LLC and RBC Capital Markets as Joint Lead Arrangers and Joint Lead Bookrunners.

“We are pleased to increase the borrowing capacity of our revolving credit facility, which provides us with additional financial flexibility to continue pursuing our growth strategy,” stated Frank Semple, Chairman, President and Chief Executive Officer.  “We appreciate the continued support of the strong lender group in our credit facility.”

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MarkWest Energy Partners, L.P. is a master limited partnership engaged in the gathering, transportation, and processing of natural gas; the transportation, fractionation, marketing, and storage of natural gas liquids; and the gathering and transportation of crude oil. MarkWest has extensive natural gas gathering, processing, and transmission operations in the southwest, Gulf Coast, and northeast regions of the United States, including the Marcellus Shale, and is the largest natural gas processor and fractionator in the Appalachian region.

This press release includes “forward-looking statements.”  All statements other than statements of historical facts included or incorporated herein may constitute forward-looking statements. Actual results could vary significantly from those expressed or implied in such statements and are subject to a number of risks and uncertainties. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect our operations, financial performance, and other factors as discussed in our filings with the Securities and Exchange Commission.  Among the factors that could cause results to differ materially are those risks discussed in the periodic reports we file with the SEC, including our Annual Report on Form 10-K for the year ended December 31, 2010, and our Quarterly Reports on Form 10-Q for the quarters ended June 30, 2011, and September 30, 2011. You are urged to carefully review and consider the cautionary statements and other disclosures made in those filings, specifically those under the heading “Risk Factors.”  We do not undertake any duty to update any forward-looking statement except as required by law.