- Access Midstream Partners, L.P
- Anadarko Petroleum Corporation
- Atlas Energy, L.P.
- Burnett Oil Company
- Cabot Oil & Gas Corporation
- Chesapeake Energy Corporation
- Chevron Corporation
- Chief Oil & Gas LLC
- Columbia Pipeline Group
- CONSOL Energy
- DTE Pipeline Company
- Endeavour International Corp.
- EOG Resources
- EQT Corporation
- EdgeMarc Energy Holdings, Inc.
- Energy Corporation of America
- EXCO Resources (PA), LLC
- Hilcorp Energy Company
- Huntley & Huntley Energy Exploration, LLC.
- Hunt Marcellus Operating Company, LLC
- Inflection Energy, LLC
- MarkWest Liberty Midstream & Resources, LLC
- Mitsui E&P USA
- Noble Energy, Inc.
- Pennsylvania General Energy Company
- Peoples Natural Gas
- PVR Midstream
- Range Resources
- Rex Energy Corporation
- Seneca Resources Corporation
- Shell Appalachia
- Southwestern Energy
- Statoil
- Sumitomo Corporation of America
- Sunoco Logistics
- Talisman Energy USA, Inc.
- Tenaska
- Triana Energy
- UGI Energy Services
- Ultra Resources
- Williams Companies
- WPX Energy
- XTO Energy
