The Tangguh gas field is a gas field lies in Berau Gulf and Bintuni Bay, in the province of West Papua, Indonesia. The natural gas field contains over of proven natural gas reserves, with estimates of potential reserves reaching over . The Tangguh field is developed by a consortium of international companies, led by BP (37% stake), CNOOC (17%), and Mitsubishi Corporation (16.3%). Smaller partners include the Japanese companies Nippon Energy, Kanematsu, Sumitomo, and Nissho Iwai. Production began in June 2009. Natural gas extracted from the field will be liquefied and the resulting LNG transported to Asian customers, mostly in China, South Korea, Japan. The project is expected to allow Indonesia to keep a significant share of world LNG market, compensating the progressive phase-out of the Arun terminal in Sumatra, whose reserves are largely depleted. Background Indonesia is a prolific oil and gas country with discovered reserves of more than and . Most of the reserves originate from Tertiary source rocks and are trapped in Tertiary reservoirs on or immediately offshore of Java, Sumatra and Kalimantan. Though these western areas have been the main focus of the country's petroleum activities, explorers have searched for giant accumulations in eastern Indonesia for more than a century. In Irian Jaya, Trend Exploration discovered about of Miocene-sourced oil in Tertiary reefs in the Salawati Basin during the 1970s. Phillips, Conoco, Total and Occidental subsequently tried to emulate Trend's success by exploring the adjacent Bintuni Basin, but found only about , shallow onshore oil field called Wiriagar in 1981 and some uneconomic offshore gas in the early 1990s. Arco entered Irian Jaya in 1989 by farming into a Conoco-led partnership holding an onshore block called KBSA on the northern side of Berau Bay. Gene Richards, Arco Indonesia's exploration vice president, executed the original farm-in as an opportunity to explore for large reserves in a frontier area where Pertamina had recently instituted improved fiscal terms. Two dry holes were drilled in 1990, and Arco faced a decision -- to drop out of the Production Sharing Contract (PSC) and exit Irian Jaya, or to continue exploration in the Bintuni Basin. Looking deeper The Tangguh LNG project in Eastern Indonesia was started with the Wiriagar Deep-1 gas discovery, drilled by Arco’s New Venture team led by Suherman Tisnawidjaja as Arco Indonesia New Venture exploration manager. Suherman replaced Dick Garrard as a New Venture Manager in late 1991. Suherman’s