• Exploration Co. of Delaware Inc.
• Far East Energy Corp.
• Fieldpoint Petroleum Corp.
• Forest Oil Corp.
• Frontier Oil Corp.
• Gasco Energy, Inc.
• Gateway Energy Corp.
• Genesis Energy, LP
• GeoGlobal Resources Inc.
• GeoResources, Inc.
• Giant Industries, Inc.
• GMX Resources Inc.
• Goodrich Petroleum Corp.
• Gulfport Energy Corp.
• GulfTerra Energy Partners LP
• GulfWest Energy Inc.
• Hallador Petroleum Co.
• Harvest Natural Resources Inc.
• Holly Corp.
• Houston Exploration Co.
• Inergy, L.P.
• Isramco, Inc.
• Ivanhoe Energy Inc.
• Kaneb Services LLC
• KCS Energy, Inc.
• Kerr-McGee Corp.
• Kestrel Energy, Inc.
• Link Energy LLC
• Lyondell Chemical Co.
• Magellan Petroleum Corp.
• Magnum Hunter Resources Inc.
• Marathon Oil Corp.
• MarkWest Hydrocarbon, Inc.
• Matrix Energy Services Corp.
• McMoRan Exploration Co.
• Mercury Air Group Inc.
• Meridian Resource Corp.
• Mission Resources Corp.
• Murphy Oil Corp.
• Nation Energy, Inc.
• National Energy Group Inc.
• Ness Energy International Inc.
• Newfield Exploration Co.
• Nexen Inc.
• Noble Energy, Inc.
• Occidental Petroleum Corp.
• Oceanic Exploration Co.
• PANACO, Inc.
• Panhandle Royalty Co.
• Parallel Petroleum Corp.
• Patina Oil & Gas Corp.
• Pengrowth Energy Trust
• Penn Octane Corp.
• Penn Virginia Corp.
• Petrohawk Energy Corp.
• Petroleum Development Corp.
• PetroQuest Energy, Inc.
• Petsec Energy Ltd.
• Pioneer Natural Resources Co.

• Plains Exploration & Production Co.
• Plains Resources Inc.
• Pogo Producing Co.
• Premcor Inc.
• Premier Oil plc
• Prima Energy Corp.
• PrimeEnergy Corp.
• PrimeWest Energy Trust
• Probex Corp.
• Prolong International Corp.
• PYR Energy Corp.
• Pyramid Oil Co.
• Quest Resource Corp.
• Quicksilver Resources Inc.
• Range Resources Corp.
• Seven Seas Petroleum Inc.
• Sinopec Shanghai Petrochemical Co. Ltd.
• Sonoran Energy, Inc.
• Southern Pacific Petroleum NL
• Southwestern Energy Co.
• St. Mary Land & Exploration Co.
• Star Gas Partners LP
• Stone Energy Corp.
• Streicher Mobile Fueling Inc.
• Sunoco, Inc.
• Superior Oil & Gas Co.
• Swift Energy Co.
• Syntroleum Corp.
• TAG Oil Ltd.
• Talisman Energy Inc.
• Tatham Offshore, Inc.
• Tengasco, Inc.
• Tesoro Petroleum Co. Inc.
• Teton Petroleum Corp.
• Tom Brown, Inc.
• Torch Energy Royalty Trust
• Toreador Resources Corp.
• Trans Energy, Inc.
• TransGlobe Energy Corp.
• Transmeridian Exploration Inc.
• TransMontaigne, Inc.
• Transportadora de Gas del Sur SA
• Tri-Valley Corp.
• U.S. Energy Corp.
• Ultra Petroleum Corp.
• Ultrapar Holdings Inc.
• Unit Corp.
• United Heritage Corp.
• Unocal Corp.
• VAALCO Energy, Inc.
• Valero Energy Corp.
• Venus Exploration, Inc.
• Vintage Petroleum, Inc.
• VTEX Energy, Inc.
• Western Gas Resources Inc.
• Westport Resources Corp.
• Whiting Petroleum Corp.
• Wilshire Enterprises, Inc.
• World Fuel Services Corp.
• XCL, Ltd.
• XTO Energy Inc.