Petroliam Nasional Bhd (Petronas)
China National Offshore Oil Corp.
Southern Oil of Louisiana
Southwestern Production Corp.
PTT Exploration and Production Public Co. Ltd. (PTTEP)
Pioneer Natural Resources Co.
Neptune Energy Group Ltd.
Pemex (Petroleos Mexicanos)
Southwestern Production Corp.
China National Offshore Oil Corp.
Bedrock Energy Partners LLC
Burlington Resources Oil & Gas Co.