| Company Name | Company URL |
| Abu Dhabi National Oil Company (ADNOC) | http://www.adnoc.com |
| Addax Petroleum | http://www.addaxpetroleum.com |
| Agip-ENI | http://www.agip.it |
| Alliance Gas (now: STATOIL) | http://www.statoil.co.uk |
| Alon USA | http://www.alonusa.com |
| Amerada Hess | http://www.hess.com |
| Amerossi | http://www.amerossi.com |
| Anadarko | http://www.anadarko.com |
| Anglo Siberian Oil Company plc. | http://www.anglosiberianoil.co.uk |
| Anonima Petroli Italiana (API) | http://www.apioil.com |
| ARCO (BP Amoco) | http://www.bpamoco.com |
| Aruba Petroleum | http://www.arubapetroleum.com |
| Atlantic Petroleum, Faroe Islands | http://www.petroleum.fo |
| Australian Worldwide Exploration Limited | http://www.awexp.com.au |
| Bay State Gas | http://www.baystategas.com |
| BEB (Hannover) | http://www.beb.de |
| Bharat Petroleum | http://www.bharatpetroleum.com |
| BHP Billiton | http://www.bhpbilliton.com |
| Black Hills Exploration and Production | http://www.bhep.com |
| Bow Valley Energy Ltd. (US) | http://www.bvenergy.com |
| BP | http://www.bp.com |
| Cabot Oil & Gas Corporation | http://www.cabotog.com |
| Cairn Energy PLC | http://www.cairn-energy.plc.uk |
| Caltex Petroleum Company | http://www.caltex.com |
| Canadian Natural Resources | http://www.cnrl.com |
| CanArgo Energy | http://www.canargo.com |
| CanBaikal Resources Inc. | http://www.canbaikal.com |
| Chevron | http://www.chevron.com |
| ChevronTexaco | http://www.chevrontexaco.com |
| Chieftain International (now: Huntoil) | http://www.huntoil.com |
| China National Petroleum Corporation | http://www.cnpc.com.cn/eng |
| Chinese Petroleum Corporation (Taiwan) | http://www.cpc.com.tw |
| Citgo, Venezuela | http://www.citgo.com |
| CNOOC Ltd., China | http://www.cnooc.com.cn |
| CONOCO (US) (incl. Gulf Canada) | http://www.conoco.com |
| ConocoPhillips | http://www.conocophillips.com |
| Crown Central Petroleum, United States | http://www.crowncentral.com |
| CSIRO Exploration and Mining | http://www.em.csiro.au |
| Dana Petroleum plc. | http://www.dana-petroleum.com |
| Devon Energy Corporation | http://www.dvn.com |
| Dominion Exploration & Production | http://www.dom.com |
| Ecopetrol, Colombia | http://www.ecopetrol.com.co/english |
| Elf Aquitaine (TOTAL FINA ELF) | http://www.totalfinaelf.com |
| Elinoil Hellenic Petroleum Company S.A. | http://www.elin.gr |
| Empresa Colombiana de Petróleos (ECOPETROL) | http://www.ecopetrol.com.co |
| Empresa Nacional del Petróleo - (ENAP) | http://www.enap.cl |
| Enbridge, Canada | http://www.enbridge.com |
| Eni | http://www.eni.it |
| ESSO Deutschland | http://www.esso.de |
| ExxonMobil | http://www.exxon.mobil.com |
| Faroe Petroleum, Faroe Islands | http://www.faroe-petroleum.com |
| Galp Energia, Portugal | http://www.galpenergia.com |
| Gás de Portugal (now: Galp Energia) | http://www.galpenergia.com |
| Gasum Oy (FI) | http://www.gasum.fi |
| Gaz de France | http://www.gazdefrance.com |
| Grupa LOTOS, Poland | http://www.lotos.pl |
| Gujarat State Petroleum Corporation | http://www.gujaratpetro.com |
| Gulf Canada (now: Conoco) | http://www.conoco.com |
| Gulf Oil, United States | http://www.gulfoilltd.com |
| Halliburton Company | http://www.halliburton.com |
| Hellenic Petroleum, Greece | http://www.hellenic-petroleum.gr |
| Hibernia | http://www.hibernia.ca |
| Hindustan Petroleum Corporation Limited | http://www.hindpetro.com |
| Hurricane Hydrocarbons Ltd. (CA) | http://www.hurricane-hhl.com |
| Husky Oil | http://www.husky-oil.com |
| Iceland Oil | http://www.olis.is |
| INA (Industrija Nafte), Croatia | http://www.ina.hr |
| Indian Oil Corporation | http://www.iocl.com |
| Irving Oil | http://www.irvingoil.com |
| Korea National Oil Corporation (KNOC) | http://www.knoc.co.kr |
| Kuwait National Petroleum Company (KNPC) | http://www.knpc.com.kw |
| Louis Dreyfus Natural Gas (now: Dominion) | http://www.dom.com |
| Lukoil | http://www.lukoil.com |
| Lundin Oil AB. | http://www.lundinoil.com |
| Maersk Olie og Gas | http://www.maersk.dk |
| Marathon Oil Company | http://www.marathon.com |
| Maxol Group | http://www.maxol.ie |
| Mol Group | http://www.molgroup.hu |
| Mosaic Oil | http://www.mosaicoil.com |
| Murphy Oil Corporation | http://www.murphyoilcorp.com |
| Naftna Industrija Srbije, Serbia | http://www.nis.yu |
| National Oil Corporation of Kenya | http://www.nockenya.co.ke |
| Nederlandse Gasunie | http://www.gasunie.nl |
| Nexen Inc. (CA) (formerly Canadian Occidental Petroleum Ltd.) | http://www.cdnoxy.com |
| Nigerian National Petroleum Corporation | http://www.nnpcgroup.com |
| NIS-NAFTAGAS | http://www.nis-naftagas.co.yu |
| Norsk Hydro | http://www.hydro.com |
| North Atlantic Petroleum | http://www.northatlantic.ca |
| Northern Territory Oil Limited | http://www.ntoil.com.au |
| Occidental Petroleum Company | http://www.oxy.com |
| ODIN Energi ApS (Danmark) | http://www.odinenergi.com |
| Oil & Gas Petroleum Corporation | http://www.oilgaspetroleum.com |
| Oil and Natural Gas Corporation India | http://www.ongcindia.com |
| Oil India Limited | http://www.oilindia.nic.in |
| OMV Erdöl und Erdgas | http://www.omv.com |
| Perupetro SA | http://www.perupetro.com.pe |
| Petro Canada | http://www.petro-canada.com |
| Petrobras | http://www.petrobras.com.br |
| PetroChina | http://www.petrochina.com.cn |
| Petrodril | http://www.petrodril.com |
| Petrogal (PT) | http://www.petrogal.pt |
| Petróleos de Venezuela | http://www.pdv.com |
| Petróleos Mexicanos | http://www.pemex.com |
| Petron Corporation, Philippines | http://www.petron.com |
| Petronas | http://www.petronas.com |
| Petronet LNG Limited, India | http://www.petronetlng.com |
| Petrotrin | http://www.petrotrin.com |
| Philippine National Oil Company | http://www.pnoc.com.ph |
| Phillips Petroleum Company | http://www.phillips66.com |
| PKN Orlen S.A., Poland | http://www.orlen.pl |
| Pogo Producing | http://www.pogoproducing.com |
| Premier Oil | http://www.premier-oil.com |
| PSO, Pakistan | http://www.psopk.com |
| Qatar Petroleum | http://www.qp.com.qa |
| Ramco | http://www.ramco-plc.com |
| Reliance Industries Limited, India | http://www.ril.com |
| REPSOL YPF | http://www.repsol.es |
| Rompetrol Group N.V. | http://www.rompetrol.com |
| RWE | http://www.rwe.de |
| Santos | http://www.santos.com.au |
| Sasol, South Africa | http://www.sasol.com |
| Saudi Aramco | http://www.saudiaramco.com |
| Schlumberger | http://www.slb.com |
| Shell (US) | http://www.shellus.com |
| Shell International | http://www.shell.com |
| Sinopec, China | http://english.sinopec.com |
| SOCAR | http://www.socar.gov.az |
| Sonangol, Angola | http://www.sonangol.com |
| Sonatrach, Algeria | http://www.sonatrach-dz.com |
| Staatsolie (Suriname) | http://www.staatsolie.com |
| Statoil | http://www.statoil.com |
| Stuart Petroleum Limited | http://www.stuartpetroleum.com.au |
| Suncor | http://www.suncor.com |
| Surgutneftegaz | http://www.surgutneftegas.ru |
| Syncrude | http://www.syncrude.ca |
| Talisman energy | http://www.talisman-energy.com |
| TAMOIL | http://www.tamoil.ch |
| Tap Oil | http://www.tapoil.com.au |
| Teikoku (JP) | http://www.teikokuoil.co.jp |
| TNK-BP | http://www.tnk.ru |
| Todd Energy | http://www.toddenergy.co.nz |
| Tokyo Gas | http://www.tokyo-gas.co.jp |
| TransCanada | http://www.transcanada.com |
| Tullow Oil plc | http://www.tullowoil.com |
| Turkish Petroleum Corporation (TPAO) | http://www.tpao.gov.tr |
| Turkish Petroleum International Company Ltd | http://www.tpic.com.tr |
| United Petroleum, Australia | http://www.unitedpetroleum.com.au |
| United Refining Company | http://www.urc.com |
| UNOCAL | http://www.unocal.com |
| Vaalco Energy Inc. | http://www.vaalco.com |
| Wingas GmbH | http://www.wingas.de |
| Wintershall AG (BASF) | http://www.wintershall.de |
| Woodside Petroleum | http://www.woodside.com.au |
| YPFB, Bolivia | http://www.ypfb.gov.bo |
| YUKOS, Russia | http://www.yukos.com |
| ZPL Energy Inc | http://www.zplenergy.com |
