- Apache Corp
- BP Pipeline North America
- Caprock Oil & Gas Inc
- Cross Timbers Production Co
- Devon Energy Corp
- Duke Oil & Gas
- Eott Energy Pla Andrews Sta
- Exxon Mobil Corp
- Hunt Oil Co
- J Cleo Thompson Oil Co
- John R Parish Co
- Kelton Operating Corp
- Maralo Inc
- Maralo LLC
- O F Hamilton Oil Co
- Range Resources
- Rockpointe Resources Inc
- Scott's Services
- Snow Oil & Gas Inc
- Sunray Energy Inc
- Unocal Pipeline Co
- Vin Fisher Oil Co
- Westport Oil & Gas
