2006 :
-:
Addax Petroleum
AGIP - KCO
Apache North Sea
BG Group
BP
Cairn Energy plc
CNR International
ConocoPhillips
Enap Sipetrol
Eni
Eni E&P Division
ExxonMobil
GEPetrol
Hess Corporation
Maersk Oil
Marathon Oil UK Ltd
Nexen
Noble Energy Inc.
Norsk Hydro Oil & Energy
OMV
Petrobras
Petro-Canada
Petroleum Development Oman
PetroSA
Pioneer Natural Resources
Premier Oil plc
RepsolYPF
Sasol Petroleum International
Saudi Aramco
Shell
Silverstone Energy Ltd
Sonangol
Statoil
Total
US State Department