- Agave
- AGLSC
- AKA Energy
- Alliance
- Atlas
- Blueknight
- BP America New
- Brigham Oil & Gas, L.P./Statoil
- Buckeye
- Celero Energy II, L.P.
- Centurion
- CH2MHILL, Inc.
- Chesapeake
- Chevron
- CITGO
- COG/Marbob
- Copano Pipelines
- Crescent Point Energy US Corp
- DCP
- Deep Rock
- Eagle Rock Energy Partners
- El Paso Energy Services Company
- EMW Gas
- Enbridge
- Energen Resources
- Energy Transfer
- EXCO
- Exterran/Hanover
- Gowan Construction
- Holly Energy Partners
- Magellan
- Manzano
- Marathon
- Nicholas Cons Group
- Newfield Exploration
- Noble Energy
- Nuevo
- Nustar
- Occidental Permian
- Red Cedar
- RKI
- S&G
- Saddle Butte
- SandRidge Energy Cummings
- Southern Star
- Spectra
- Southwest Energy
- Sunoco
- Tesoro
- UNEV Pipeline
- Whiting Petroleum Corp.
- Williams