Mari Gas Field, located at Daharki, District Ghotki, Sindh, approximately 96 kilometers North of Sukkur. Esso Eastern Inc (EEI) discovered this field in 1957 with the drilling of first well – Mari X-1. It was drilled to the depth of 11110 feet. The gas was encountered at the depth of 2300 feet in Lower Kirthar ZN-‘B’ Limestone formation, commonly known as Habib Rahi Limestone. The field was brought on production in 1967 when the required infrastructure was established to supply 30 MMSCF/Day gas to fertilizer plant of Esso Pakistan Fertilizer Company Limited – now Engro Chemical Pakistan Limited.

Mari Gas Field was owned by Pak Stanvac Petroleum Project (PSPP), a joint venture between Government of Pakistan as 49% interest owner and EEI as 51% interest owner and operator with marketing rights over entire production from the field. The field was operated under this arrangement till 1983 when Fauji Foundation acquired the entire 51% interest of EEI in PSPP alongwith its branch office and operated the field till December 22, 1985. Fauji Foundation, Government of Pakistan and Oil and Gas Development Corporation (now Oil and Gas Development Company Limited) incorporated Mari Gas Company Ltd as an unlisted public limited company on December 04, 1984 to takeover the assets, liabilities and operation of Fauji Foundation (Mari Gas) and Pak Stanvac Petroleum Project. The Company commenced business in its own name on December 23, 1985.