AGIP-KCO
AMOCO Netherlands BV
ARCO
BEB, Erdgas und Erdol GmbH, Germany
British Petroleum
Brunei Shell Petroleum
Clyde Petroleum Exploratie BV
Continental Netherlands Oil Company
ELF Petroland BV
Endeavour Energy UK Ltd
ECL
Eni S.p.A. Divisione Agip
Forest Oil
GasPlus Italia
Gaz de France Production Nederland B.V.
GeoEnpro Petroleum
Gulf
Gulfsands Syria
Maersk Oil and Gas
Maghreb Petroleum Exploration S.A.
Magyar Horizont Energia
Mobil Producing Netherlands Inc.
Nederlandse Aardolie Maatschappij BV
Nippon Oil Exploration Malaysia Ltd
NITG-TNO (Dutch Geological Survey)
Occidental Netherlands Inc.
PanCanadian Petroleum International Ltd.
Petroleum Development Oman
Petro-Canada Netherlands
PetroIran
Petroleum Development Oman
PETRONAS Research & Scientific Services Sdn Bhd
Placid International Oil Ltd.
Preussag Germany
Reliance Industries Ltd.
Robertson Research International Limited
Sakhalin Energy Investment Company Ltd
Saudi Aramco
Shell Angola
Shell China
Shell Congo
Shell Europe
Shell Gabon
Shell Namibia
Shell Kazakhstan
Shell India
Shell Falklands
Shell Petroleum Development Peru
Shell Philippines
Shell Research Rijswijk (SIEP)
Shell Temir Petroleum Development B.V
Statoil
Total E&P
TransCanada Netherlands
UNOCAL Netherlands BV
Veba Oil
Wintershall Noordzee BV
Wintershall AG
Wintershall Libya