MarkWest Utica EMG Expands Utica Shale Midstream Infrastructure

  MarkWest Utica EMG Expands Utica Shale Midstream Infrastructure

Business Wire

DENVER -- May 30, 2013

MarkWest Utica EMG, L.L.C. (MarkWest Utica EMG), a joint venture between
MarkWest Energy Partners, L.P. (NYSE: MWE) (MarkWest) and The Energy and
Minerals Group (EMG), is announcing an additional expansion of its large-scale
midstream system to support the rapidly growing drilling programs of Antero
Resources (Antero), Gulfport Energy Corporation (NYSE: GPOR) (Gulfport) and
other producers in the southern core of the Utica Shale. MarkWest Utica EMG
will now construct a third 200 million cubic feet per day (MMcf/d) cryogenic
gas processing facility at its Seneca processing complex in Noble County,
Ohio.

The Seneca complex continues to expand and will include three processing
plants totaling 600 MMcf/d. The first two plants are scheduled to begin
operations during the fourth quarter of 2013 and will support rich-gas
production from a number of key producers including Antero, Gulfport, Rex
Energy, PDC Energy, Consol Energy and others. In addition to the Seneca I
facility, Antero’s rich-gas production will also anchor the Seneca III
facility, and MarkWest Utica EMG expects the plant to be operational in early
second quarter of 2014. Antero is a premier operator in the Northeast and is
quickly developing its significant acreage position in areas surrounding the
Seneca complex.

MarkWest Utica EMG is also developing the Cadiz complex in Harrison County,
Ohio, which is anchored by Gulfport. Gulfport is successfully executing on its
significant drilling program and continues to report very strong well results
and rapidly growing production. In the past two weeks MarkWest Utica EMG began
operations of the first major cryogenic processing facility in eastern Ohio,
the 125 MMcf/d Cadiz I plant. The Cadiz complex currently has 185 MMcf/d of
processing capacity, which includes a 60 MMcf/d interim refrigeration plant.
The capacity at Cadiz will increase to 325 MMcf/d by mid-2014 with the
completion of Cadiz II, a 200 MMcf/d plant and the removal of the Cadiz
interim plant. The Cadiz and Seneca complexes will be connected by a rich-gas
header that will provide Utica producers with unparalleled redundancy and
reliability.

In just over a year, MarkWest Utica EMG has executed agreements with seven
producers developing acreage in the southern core of the Utica Shale. By
mid-2014 MarkWest Utica EMG’s fully integrated midstream system in the Utica
Shale will consist of more than three-hundred miles of gathering pipeline,
five processing facilities totaling almost 1 billion cubic feet per day and
100,000 barrels per day (Bbl/d) of C2+ fractionation capacity. The joint
venture’s midstream system will also be connected to MarkWest’s expansive
Marcellus NGL infrastructure.

“We are very excited to be developing premier midstream solutions in the
southern core of the Utica shale for successful and proven operators such as
Antero and Gulfport,” stated Frank Semple, Chairman, President, and Chief
Executive Officer of MarkWest. “Together with our joint venture partner EMG,
we are committed to providing our producer customers with fully-integrated
midstream infrastructure and award winning customer service in one of
America’s most exciting emerging resource plays.”

MarkWest Energy Partners, L.P. is a master limited partnership engaged in the
gathering, processing and transportation of natural gas; the gathering,
transportation, fractionation, storage and marketing of natural gas liquids;
and the gathering and transportation of crude oil. MarkWest has a leading
presence in many unconventional gas plays including the Marcellus Shale, Utica
Shale, Huron/Berea Shale, Haynesville Shale, Woodford Shale and Granite Wash
formation.

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 (SEC). 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, 2012 and our Quarterly Report on
Form 10-Q for the quarter ended March 31, 2013. 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.

The Energy & Minerals Group is a highly specialized private equity firm that
focuses exclusively on investing across various facets of the global natural
resource industry that are integral to the global economy. EMG has $6.2
Billion of total investor commitments (including co-investments) with in
excess of $3.1 Billion deployed across the energy complex since inception. For
additional information on EMG, please contact Alexandra Coolidge at
713-579-5029.

Contact:

MarkWest Energy Partners, L.P.
Frank Semple, 866-858-0482
Chairman, President & CEO
or
Nancy Buese, 866-858-0482
Senior VP & CFO
or
Josh Hallenbeck, 866-858-0482
VP of Finance & Treasurer
investorrelations@markwest.com