- Atlantic Operating, Inc.
- Chisos Operating, Inc.
- Devon Energy
- Eagle Oil & Gas Co.
- Encore
- Endeavor Energy Resources
- Fasken Oil and Ranch
- FIML Resources
- MEDCO Energi
- Murchison Oil & Gas, Inc.
- OGX Resources, LLC
- Petrohawk Energy Corporation
- Petrohunt
- Primexx Operating Corporation
- Quantum Resources Management, LLC
- Quicksilver Resources
- Ram Energy Resources, Inc.
- Read & Stevens, Inc.
- Slawson Exploration
- Tammany Oil & Gas LLC
- Three Rivers Operating Company LLC
- Torch Energy Advisors, Inc.
- Trilogy Operating, Inc.
- Whiting Petroleum Corporation
- XTO Energy
