8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF

THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): March 6, 2012

MARKWEST ENERGY PARTNERS, L.P.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization) 001-31239 (Commission File Number) 27-0005456 (I.R.S. Employer Identification Number)

1515 Arapahoe Street, Tower 1, Suite 1600, Denver CO 80202

(Address of principal executive offices)

Registrant’s telephone number, including area code: 303-925-9200

Not Applicable.

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

oWritten Communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-Commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-Commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 8.01. Other Events.

On March 6, 2012, MarkWest Utica EMG, L.L.C. (“MarkWest Utica”), a joint venture between MarkWest Energy Partners, L.P. (the “Partnership”) and The Energy and Minerals Group focused on the development of significant natural gas gathering, transportation, and processing and natural gas liquid (“NGL”) transportation, fractionation, and marketing infrastructure in the Utica shale in eastern Ohio, announced the execution of a letter of intent (“LOI”) with Gulfport Energy Corporation to provide gathering, processing, fractionation, and marketing services in the liquids-rich corridor of the Utica.

Under the terms of the LOI, which requires the execution of definitive agreements, MarkWest Utica will develop extensive natural gas gathering infrastructure with Gulfport and other producers primarily in Harrison, Guernsey, and Belmont counties that is expected to come online beginning in 2012.  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.

ITEM 7.01. Regulation FD Disclosure.

On March 6, 2012, the Partnership issued a press release announcing a letter of intent to develop significant midstream infrastructure in the Utica shale.  A copy of the press release is furnished as Exhibit 99.1 hereto.

The information contained in this Item 7.01 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Information contained in this Current Report on Form 8-K may include certain statements concerning expectations for the future that are forward-looking statements as defined by federal law. Actual results could vary significantly from those expressed or implied in such statements and are subject to a variety of known and unknown risks, uncertainties, and other factors that are difficult to predict and many of which are beyond management’s control. Among the factors that could cause results to differ materially are those risks discussed in the periodic reports we file with the Securities and Exchange Commission, including our Annual Report on Form 10-K for the year ended December 31, 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.”

2

ITEM 9.01.	Financial Statements and Exhibits.
(d)	Exhibits.

Exhibit No.	Description of Exhibit
99.1	Press release dated March 6, 2012 announcing a letter of intent to develop significant midstream infrastructure in the Utica shale.

3

SIGNATURE

Pursuant to the requirements of the Securities and Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	MARKWEST ENERGY PARTNERS, L.P.
	(Registrant)
	By:	MarkWest Energy GP, L.L.C.,
		Its General Partner
Date: March 7, 2012	By:	/s/ NANCY K. BUESE
		Nancy K. Buese
		Senior Vice President and Chief Financial Officer

4

EX-99.1

Exhibit 99.1

Contact:	Frank Semple, Chairman, President and CEO Nancy Buese, Senior VP and CFO	Contact:	John Raymond, Managing Partner & CEO Jeff Rawls, Managing Director
	Dan Campbell, VP of Finance/Treasurer		Patrick Wade, Managing Director
Phone:	(866) 858-0482	Phone	(713) 579-5000
E-mail	investorrelations@markwest.com

MarkWest Utica Announces Letter of Intent to Develop

Significant Midstream Infrastructure in the Utica Shale

DENVER—March 6, 2012— 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 significant 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 execution of a letter of intent 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 LOI, which requires the execution of definitive agreements, MarkWest Utica will develop extensive natural gas gathering infrastructure with Gulfport and other producers primarily in Harrison, Guernsey, and Belmont counties that is expected to come online beginning in 2012.  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.

“We are very excited to announce the development of midstream infrastructure with Gulfport and other producers to fully develop the rich-gas acreage in the southern Utica shale,” said Frank Semple, Chairman, President and Chief Executive Officer of MarkWest.  “The full spectrum of natural gas midstream services, particularly the fractionation and marketing of NGLs at a world-scale fractionation complex, is essential to the success of Utica producers, and we are excited to work closely with our producer customers to develop this prolific shale play.”

###

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 totaling in excess of $3.3 billion of 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 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. 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.