2JM Exploration, L.L.C.
Abraxas Petroleum Corporation
Activia Resources L.L.C.
Alamo Energy, L.L.C.
Alamo Operating Company, L.C.
All American Oil & Gas
American Energy Partners
Ameristate Exploration, L.L.C.
Ameritex Minerals, Inc.
Amexco
Aminex USA, Inc.
Anglo-European II Corp.
Apache Corp.
Austin Exploration Limited
AWP Operating Company .
Bayshore Exploration, L.L.C.
Beach Tex Oil
Beckham Resources, Inc.
Benchmark Oil & Gas Company
Black Brush Oil & Gas, L.P.
Black Forest Energy, L.L.C.
Blue Ridge Group, Inc.
Blue Star Operating
Brigham Oil & Gas, L.P.
Broad Oak Energy, L.C.
Broadway Bank
Buccaneer Energy
Burk Royalty Co.
C S V
Caliente Energy, L.P.
Camden Resources, L.L.C.
Carrizo Oil & Gas, Inc.
C B Energy, L.L.C.
Chaparral Energy, L.L.C.
Chesapeake Energy Corporation
Cheyenne Petroleum Company
Cimarex Energy Company
CMR Energy, L.P.
Cobia Oil & Gas
Common Resources
Comstock Oil & Gas
Conoco Phillips Company
Continental Operating Co.
Crest Resources, Inc.
Croft Exploration
CSB Partners, L.L.C.
CSV
Dan A. Hughes Company
Delray Oil
Denali Oil & Gas Management
Durango Resources Corp.
Dyersdale Energy
Dynamic Production Inc.
Eagle Oil & Gas Co.
East Guadalupe Resources, LLC
Edwin M. Jones Oil Co.
Einex Energy
EOG Resources, Inc
Escarpment Energy, L.L.C.
Escondido Resources II, LLC
Espada Operations, L.L.C.
Firstrike Energy
Flatirons Resources, L.L.C.
Frazier Resources Company
Frost National Bank
Garrison Oil & Gas Ltd.
Gates Mineral Company, Ltd.
Genesis Gas & Oil, L.L.C.
Great Texas Crude, Inc.
Greehey & Company
Greenfields Petroleum Corp.
Grey Wolf Drilling Company
Gulftex Energy
Headington Oil & Gas
Heartland Energy Development
Hilcorp Energy Company
Hurd Enterprises, Ltd.
Initial Energy Services, LLC
J L Resources
Kaler Energy Corporation
KEBO Oil & Gas, Inc
Kerns Petroleum, Inc.
Kestrel Resources, Inc.
Killam Oil Company
Lewis Energy
Lighthouse Exploration, Inc.
Liveley Exploration Inc.
LOG Energy Exploration, Ltd.
Lone Star Land Energy, L.L.C.
Longfellow Exploration
Loudon Operating Company, L.L.C.

MacDiarmid Interests, Ltd.
Magnum Producing & Operating
Maguire Oil & Gas Company
Matagorda Resources
McCombs Energy, L.L.C.
Mediterranean Resources, Ltd.
Merritt and Associates
Mesa Resources, Inc.
Mestena Operating, Ltd.
Metano Energy II, L.P.
Milagro Exploration
MLC Operating, L.P. .
Mortimer Production Company
MPG Petroleum
Nakoma Petroleum
New Century Exploration, Inc.
Newfield Exploration, Inc.
Opex Energy, LLC
Orion Drilling Company, L.L.C.
Osborn Heirs Co.
Paul R. Clevenger, P. E.
Penn Virginia Oil & Gas, L.P.
Petrohawk Energy
Pioneer Drilling Company
Pool Operating
Precision Drilling Company, L.P.
Premier Mineral, Inc.
Primavera Resources
Prime Operating Company
Pyr Energy Corp.
Ram Energy Resources, Inc.
Red Arrow Energy, L.L.C.
Reichmann Petroleum Corp.
Republic Resources, L.L.C.
Ricochet Energy, Inc.
Risco La Sara Operations, L.L.C.
RLU Oil & Gas, Inc.
Roma Oil & Gas, Inc.
Rosetta Resources
Royal Production Co., Inc.
Sage Energy Company
Sanchez Oil & Gas Corporation
Saxet Energy, Ltd
Sea-Lar Management, Inc.
SEV Texas Operating, LLC
Sien Energy
Simray Operating Corp.
Sky Line Oil & Gas, LLC
Slawson Exploration Company
Smith Production, Inc.
Sonora Resources, L.P.
Sonterra Energy
South Bay Resources
Spears & Associates, Inc.
St. Mary Land & Exploration
Stephens Production Company
Strand Energy, L.C
Striker Petroleum
Sue Ann Operating, L.C.
Suemaur Exploration & Prod LLC
T-C Oil Company
Talisman Energy USA, Inc.
Talon Development Company
Tammany Exploration Co., LLC
Tejones Operating Company
Texas American Resources
Textron Energy, L.L.C.
The Exploration Company
Thorp Petroleum Corporation
Three Rivers Energy Company
Tidal Petroleum Corporation
TNT Engineering, Inc.
Touchstone Resources USA, Inc.
Traton Engineering, L.P.
Trek Resources, Inc.
Trio Consulting & Mngmt, LLC
U S Enercorp, Ltd.
Ultra Oil & Gas, Inc.
Valence Operating Company
Ventex Operating Corporation
Venus Exploration, Inc.
W. B. Osborn
Welhausen Operating Company
Western National Bank
Whiting Oil & Gas Corporation
Will Drill Production Co., Inc.
Winn Exploration Co., Inc.
XP Energy
XTO Energy
Zachry Exploration, Ltd.