- AkA Energy Group
- Anadarko Petroleum Corp.
- Atlas Energy, L.P.
- Burnett Oil Company
- Cabot Oil and Gas Corporation
- Carrizo Oil & Gas, Inc.
- Chesapeake Energy Corporation
- Chevron
- Chief Oil and Gas LLC
- CONSOL Energy
- DTE Pipeline Company
- Energy Corporation of America
- Enerplus Resources USA
- EOG Resources, Inc.
- EQT Corporation
- EXCO Resources (PA), LLC
- Hess, Inc.
- Hunt Marcellus Operating Company, LLC
- Inflection Energy, LLC
- MarkWest Liberty Midstream & Resources, LLC
- Mitsui E&P USA
- Newfield Exploration Company
- NiSource Gas Transmission & Storage
- Noble Energy, Inc.
- PDC Mountaineer, LLC
- Penn Virginia Oil & Gas Corporation
- Pennsylvania General Energy Company, LLC
- Peoples Natural Gas
- PVR Midstream
- Range Resources
- Rex Energy Corporation
- Seneca Resources Corporation
- Shell Appalachia
- Southwestern Energy
- Statoil
- Sumitomo Corporation of America
- Talisman Energy USA, Inc.
- Tenaska
- Triana Energy
- UGI Energy Services
- Ultra Resources
- Williams Companies
- WPX Energy
- XTO Energy, Inc.
