Anadarko Petroleum Corporation
AXIO Natural Resources
Belden & Blake Corporation
Bentley-Simonson, Inc.
BG Group plc
Black Stone Minerals Company, L.P.
Blacksand Energy, Inc.
BlackWell Energy Group LLC
Bonanza Creek Energy Company LLC
BreitBurn Energy Group LLC
BRG Petroleum Corporation
Cano Petroleum, Inc.
Carl E. Gungoll Exploration, Inc.
Carrizo Oil & Gas, Inc.
CDX Gas, LLC
Chesapeake Energy Corporation
ChevronTexaco Corporation
Classic Petroleum Inc.
Davis Petroleum Corporation
Devon Energy Corporation
Dune Energy, Inc.
EnCana Corporation
Endeavor International Corporation
Energy Corporation of America
Energy XXI
Ensight Energy Partners, L.P.
Evergreen Resources Corporation
Faulkner O'Brien Energy
First Reserve Corporation
GASCO
Genesis Petroleum Corporation Plc
Hilcorp Energy Company
IMTT
Ithaca Energy Inc.
J.M. Huber Corporation
JMI Energy, LLC
KFx Inc.
Latigo Petroleum, Inc.
Linn Energy, LLC
Madagascar Oil Sarl
Meritage Energy Partners, LLC
Nuevo Energy Company
Ovation Energy
Parallel Petroleum Corporation
Pinnacle Gas Resources
Pioneer Natural Resources Company
Pioneer Petroleum
Pogo Producing Company
Premier
Ram Energy Resources, Inc.
Remington Oil & Gas Corporation
Scythian, Ltd.
Seaboard Oil Company
Spinnaker Exploration
Stream Energy, Inc.
Swift Energy Company
Tartan Energy, Inc.
TexCal Energy
Texlan Enterprises, ltd.
Torch Energy Advisors incorporated
Total
Transmeridian Exploration, Inc.
Tristan
XCL
XTO Energy Inc.
