Exhibit 99.1


                                 FOOTNOTES
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(1)  This statement is being filed by The Goldman Sachs Group, Inc. ("GS
     Group"), Goldman, Sachs & Co. ("Goldman Sachs"), GSCP V Advisors,
     L.L.C. ("GSCP Advisors"), GSCP V Offshore Advisors, L.L.C. ("GSCP
     Offshore Advisors"), GS Advisors V, L.L.C. ("GS Advisors"), Goldman,
     Sachs Management GP GmbH ("GS GmbH"), GS Capital Partners V Fund, L.P.
     ("GS Capital"), GS Capital Partners V Offshore Fund, L.P. ("GS
     Offshore"), GS Capital Partners V GmbH & Co. KG ("GS Germany"), and GS
     Capital Partners V Institutional, L.P. ("GS Institutional" and,
     together with GS Capital, GS Offshore and GS Germany, the "Funds"),
     McJ Holding LLC and McJ Holding Corporation (GS Group, Goldman Sachs,
     GSCP Advisors, GSCP Offshore Advisors, GS Advisors, GS GmbH, the
     Funds, McJ Holding LLC and McJ Holding Corporation, collectively, the
     "Reporting Persons"). Neither the present filing nor anything
     contained herein shall be construed as an admission that any Reporting
     Person constitutes a "person" for any purpose other than for
     compliance with Section 13(d) of the Securities Exchange Act of 1934,
     as amended (the "Exchange Act").

(2)  On January 31, 2007, the Funds indirectly acquired control of a
     majority of the shares of McJunkin Corporation through control of McJ
     Holding LLC, an entity which controls McJ Holding Corporation. McJ
     Holding Corporation owns 100% of the equity interests of McJunkin
     Corporation. McJunkin Corporation owns 623,521 shares of Common Stock,
     par value $0.10 per share of PrimeEnergy Corporation (the "Shares").

     GS Group is a Delaware corporation and holding company that (directly
     and indirectly through subsidiaries or affiliated companies or both)
     is a leading investment banking organization. Goldman Sachs, a New
     York limited partnership, is an investment banking firm and a member
     of the New York Stock Exchange and other national exchanges. Goldman
     Sachs also serves as the manager for GSCP Advisors, GSCP Offshore
     Advisors and GS Advisors and the investment manager for GS Capital, GS
     Offshore, GS Germany and GS Institutional. Goldman Sachs is
     wholly-owned, directly and indirectly, by GS Group. GSCP Advisors, a
     Delaware limited liability company, is the sole general partner of GS
     Capital. GSCP Offshore Advisors, a Delaware limited liability company,
     is the sole general partner of GS Offshore. GS Advisors, a Delaware
     limited liability company, is the sole managing limited partner of GS
     Germany and the sole general partner of GS Institutional. GS GmbH, a
     German company with limited liability, is the general partner of GS
     Germany. Each of GS Capital, a Delaware limited partnership, GS
     Offshore, a Cayman Islands exempted limited partnership, GS Germany, a
     German limited partnership, and GS Institutional, a Delaware limited
     partnership, was formed for the purpose of investing in equity,
     equity-related and similar securities or instruments, including debt
     or other securities or instruments with equity-like returns or an
     equity component.

     As of January 31, 2007, both GS Group and Goldman Sachs, may be deemed
     to beneficially own 672 shares of Common Stock, par value $0.10 per
     share of PrimeEnergy Corporation ("Common Stock") which were acquired
     in ordinary course trading activities. Accordingly, as of January 31,
     2007, both GS Group and Goldman Sachs may each be deemed to
     beneficially and indirectly own an aggregate of 624,193 shares of
     Common Stock. Each of Goldman Sachs and GS Group disclaims beneficial
     ownership of the securities owned by the Funds except to the extent of
     their pecuniary interest therein, if any. Each of the Reporting
     Persons other than Goldman Sachs and GS Group disclaims beneficial
     ownership of the shares of Common Stock directly owned by Goldman
     Sachs and GS Group.

     As of January 31, 2007, each of GS Capital and its sole general
     partner, GSCP Advisors, may be deemed to own beneficially and
     indirectly an aggregate of 328,596 shares of Common Stock by reason of
     McJunkin Corporation's beneficial ownership of 623,521 shares of
     Common Stock. Each of GS Capital and GSCP Advisors disclaims
     beneficial ownership of the securities reported herein except to the
     extent of its pecuniary interest therein, if any.

     As of January 31, 2007, each of GS Offshore and its sole general
     partner, GSCP Offshore Advisors, may be deemed to own beneficially and
     indirectly an aggregate of 169,598 shares of Common Stock by reason of
     McJunkin Corporation's beneficial ownership of 623,521 shares of
     Common Stock. Each of GS Offshore and GSCP Offshore Advisors disclaims
     beneficial ownership of the securities reported herein except to the
     extent of its pecuniary interest therein, if any.

     As of January 31, 2007, GS Institutional may be deemed to own
     beneficially and indirectly an aggregate of 112,857 shares of Common
     Stock by reason of McJunkin Corporation's beneficial ownership of
     623,521 shares of Common Stock. GS Institutional disclaims beneficial
     ownership of the securities reported herein except to the extent of
     its pecuniary interest therein, if any.

     As of January 31, 2007, GS Germany and its general partner, GS GmbH,
     may be deemed to own beneficially and indirectly an aggregate of
     13,094 shares of Common Stock by reason of McJunkin Corporation's
     beneficial ownership of 623,521 shares of Common Stock. Each of GS
     Germany and GS GmbH disclaims beneficial ownership of the securities
     reported herein except to the extent of its pecuniary interest
     therein, if any.

     As of January 31, 2007, GS Advisors, the sole managing limited partner
     of GS Germany and the sole general partner of GS Institutional, may be
     deemed to own beneficially and indirectly an aggregate of 125,951
     shares of Common Stock by reason of McJunkin Corporation's beneficial
     ownership of 623,521 shares of Common Stock. GS Advisors disclaims
     beneficial ownership of the securities reported herein except to the
     extent of its pecuniary interest therein, if any.

     As of January 31, 2007, each of McJ Holding LLC and McJ Holding
     Corporation may be deemed to own beneficially and indirectly an
     aggregate of 623,521 shares of Common Stock by reason of McJunkin
     Corporation's beneficial ownership of 623,521 shares of Common Stock.
     Each of McJ Holding LLC and McJ Holding Corporation disclaims
     beneficial ownership of the securities reported herein except to the
     extent of its pecuniary interest therein, if any.

(3)  Pursuant to the Merger Agreement, dated as of December 4, 2006 among
     McJunkin Corporation, McJ Holding Corporation and Hg Acquisition
     Corp., as amended (the "Merger Agreement"), upon a sale of Shares by
     McJunkin Corporation from and after January 31, 2007, McJunkin
     Corporation has an obligation to remit to those persons who were the
     record holders of shares of McJunkin Corporation immediately prior to
     the effective time of the Merger (as defined in the Merger Agreement)
     an amount equal to 95% of the after tax proceeds from such sale.

(4)  Due to the electronic system's limitation of 10 Reporting Persons per
     joint filing this statement is being filed in two separate filings.
     This is the first of two filings.