- The Department of Mineral Fuels    - The Defense Energy Department    - Chevron Offshore (Thailand), Ltd.    - Harrods Energy (Thailand), Ltd.    - PTT Exploration and Production Plc.    - Thai Shell Exploration and Production Co., Ltd.    - Unocal Thailand, Ltd.    - Thaipo Limited    - Total Exploration and Production Thailand    - Schlumberger Overseas, S.A.    - Halliburton Company    - Baker Hughes (Thailand) Co., Ltd.    - SVS Oilfield Services Co., Ltd.