North Sumatra Offshore PSC is offshore block located in northeastern coast of Sumatra which covering area 2,127 sq km with water depths approximately 350 feet. The block signed in October 1968 to Mobil Corporation (ExxonMobil Corporation) until 1998 and has been extended for another 20 years until October 2018. The block is production block which produce gas-condensate. Producing in 1999 supply to Arun LNG plant. The block stop supply to Arun in 2014. As of September 14, 2015, 100% stake in North Sumatra Offshore (NSO) block and 100% interest in B block and 30% in PT Arun was acquired by PT Pertamina Hulu Energi NSB & NSO. 100% stake in North Sumatra Offshore (NSO) block and 100% interest in B block and 30% in PT Arun represents the combined operations of North Sumatra Offshore (NSO) block, B block, and PT Arun Natural Gas Liquefaction in their sale to PT Pertamina (Persero). 100% stake in North Sumatra Offshore (NSO) block and 100% interest in B block comprises oil and gas reserves and PT Arun Natural Gas Liquefaction produces liquefied natural gas. The blocks are located in Indonesia and PT Arun Natural Gas Liquefaction is based in Aceh, Indonesia.