MarkWest Energy Partners, L.P. : MarkWest Utica Announces Completion of Definitive Agreements with Gulfport Energy Corporation to Construct Midstream Infrastructure in the Utica Shale

MarkWest Utica EMG, L.L.C. (MarkWest Utica), a joint venture between MarkWest Energy Partners, L.P. (NYSE: MWE) and The Energy and Minerals Group (EMG) focused on the development of natural gas gathering, transportation, and processing and natural gas liquid (NGL) transportation, fractionation, and marketing infrastructure in the Utica shale in eastern Ohio, today announced the completion of definitive agreements with Gulfport Energy Corporation (NASDAQ: GPOR) to provide gathering, processing, fractionation, and marketing services in the liquids-rich corridor of the Utica.

Under the terms of the agreements, MarkWest Utica will develop natural gas gathering infrastructure primarily in Harrison, Guernsey, and Belmont counties that is expected to come online beginning in 2012. It is anticipated MarkWest Utica will have approximately 60 miles of gas gathering pipelines and associated compression to move Gulfport volumes by the end of 2012 and up to 140 miles of gathering pipelines by the first quarter of 2014. MarkWest Utica will process the gas at its Harrison County processing complex, and will provide NGL fractionation and marketing services at the Harrison County fractionator, where NGL purity products will be marketed by truck, rail, and pipeline. MarkWest Utica will initially bring online an interim 40 million cubic feet per day (MMcf/d) refrigeration natural gas processing plant at its Harrison processing complex, with an expected third quarter 2012 completion date. This interim facility will be followed by Harrison I, a 125 MMcf/d cryogenic gas processing facility, which is expected to begin operations by the first quarter of 2013. An additional 200 MMcf/d of cryogenic processing capacity for the Harrison processing complex could be installed as soon as 2013 to support the growing Utica production.

In addition to its Harrison processing complex, MarkWest Utica is developing a second processing complex in Noble County. MarkWest Utica will initially bring online an interim 45 MMcf/d per day refrigeration natural gas processing plant, with an expected fourth quarter 2012 completion date. The Noble interim facility will be followed by an additional 200 MMcf/d cryogenic processing plant, which is expected to be completed in mid-2013. The Harrison and Noble processing complexes will be connected through a NGL gathering system to the Harrison fractionation complex, which will include 100,000 barrels per day of C2+ fractionation capacity by the first quarter of 2014. The Harrison fractionation complex will be connected through an expansion of MarkWest's Marcellus NGL gathering system to its Houston fractionation complex. The Houston and Harrison facilities will be the largest fractionation complexes in the northeast, and will provide tremendous operating flexibility, and reliability, as well as market access. The Harrison fractionator will be owned jointly by MarkWest Liberty Midstream, L.L.C. and MarkWest Utica and the capital required to build the complex will be shared accordingly.

"We are very excited to support Gulfport in the development of their rich-gas acreage in the southern Utica shale," said Frank Semple, Chairman, President and Chief Executive Officer of MarkWest. "The construction of this extensive set of midstream facilities is the first step of our Utica development plan which will provide full service integrated services for our producer customers."

About MarkWest Energy Partners

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.

About The Energy & Minerals Group

The Energy & Minerals Group is the management company for a series of private equity funds with total investor commitments of $4.2 Billion, consisting of $3.1 Billion of Regulatory Assets Under Management and $1.1 Billion in co-investment commitments. EMG focuses exclusively on making direct investments across the natural resources industry in conjunction with experienced management teams focused on hard assets that are integral to existing and growing markets. For additional information on EMG, please contact John Raymond, Founder, CEO and Managing Partner at 713-579-5000.

About Gulfport

Gulfport Energy Corporation is an Oklahoma City-based independent oil and natural gas exploration and production company with its principal producing properties located along the Louisiana Gulf Coast and in the Permian Basin in West Texas. Gulfport has also acquired acreage positions in the Niobrara Formation of Western Colorado and the Utica Shale of Eastern Ohio. In addition, Gulfport holds a sizeable acreage position in the Alberta Oil Sands in Canada through its interest in Grizzly Oil Sands ULC and has interests in entities that operate in Southeast Asia, including the Phu Horm gas field in Thailand.

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 MarkWest believes that the expectations reflected in the forward-looking statements are reasonable, MarkWest can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect operations, financial performance, and other factors as discussed in 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 filed with the SEC, including MarkWest's Annual Report on Form 10-K for the year ended December 31, 2011 and its Quarterly Report on Form 10-Q for the quarter ended March 31, 2012. 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." MarkWest does not undertake any duty to update any forward-looking statement except as required by law.

MarkWest Energy Partners, L.P.
Frank Semple, Chairman, President and CEO
Nancy Buese, Senior VP and CFO
Josh Hallenbeck, VP of Finance & Treasurer
Phone: (866) 858-0482
E-mail: investorrelations@markwest.com
or
The Energy & Minerals Group
John Raymond, Managing Partner & CEO
Jeff Rawls, Managing Director
Patrick Wade, Managing Director
Phone: (713) 579-5000

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