Alta Mesa Holdings
Anadarko Petroleum Corporation
Approach Resources
Arkansas Oil & Gas Commission
Atlas America
Atlas Energy Resources
BHP Billiton
Blackbeard Operating, LLC.
BNK Petroleum
Cabot Oil & Gas Corporation
Caerus Oil and Gas
Carrizo
Casillas Petroleum
Castleton Commodities International
Charter Oak Production Company
Chesapeake Operating
Chief Oil & Gas
Cimarex
Cirque Resources
Comstock Resources
ConocoPhillips AP
Denbury Resources
Devon Energy
Diamondback Resources
Encana Oil and Gas
Energen Resources
Enerplus Resources
Enerven Compression Services
EOG Resources
EP Energy & E&P Company
EQT Production Company
EXCO Resources
FireWheel Operating
Forest Oil Corporation
Foundation Energy Management
Gulfport Energy
Halcon Resources
Hall Phoenix Energy
HG Energy
HighMount Exploration & Production
Hilcorp Energy Company
Hunt Marcellus, LLC
Hunt Oil Company
Husky Ventures
Jones Energy
Kaiser-Francis Oil Company
Linn Energy
Lonestar Resources America
Maximus Operating
Meade Energy Corporation
Mountaineer Keystone
Nadel & Gussman
New Gulf
Newfield Exploration Company
Noble Energy
Pablo Energy
PDC Energy
PetroMax Operating
PetroQuest Energy
QEP Resources
Rex Energy Corporation
Riley Exploration
RKI Exploration and Production
Sable Permian Resources
Sage Natural Resources
Samson Resources
SandRidge Energy
Shields Operating
Silver Oak Energy
Slawson Exploration Company
SM Energy
Snyder Brothers
Southwestern Energy - PA
Southwestern Energy - Fayetteville
Tecolote Energy
Triad Energy
Vitriuvian Exploration II
Ward Petroleum
XTO Energy