In 1957 when the Company was operating as Esso Eastern Inc., Mari Gas Field was discovered in Daharki, Sindh, Pakistan with initial gas reserve estimate of 3TCF. Over the years with the phased development of the Field and the subsequent reservoir evaluations the Field reserves size enhanced to 6.8TCF, thus making Mari the country’s 2nd largest gas field. Additional exploration in deeper horizon yielded a discovery of another gas reservoir of approximately 1.861TCF.

In May 1983 Fauji Foundation, a major Pakistani group with active multi-sectoral presence, including but not limited to, Oil & Gas, Cement, Power, Fertilizer,  Financial & Food Processing, acquired the entire business operations of Esso Eastern Inc. in Pakistan which comprised the Mari Gas Field.

During December 1984, the business was reorganized and incorporated as Mari Gas Company Limited (MGCL) which took over the assets, liabilities and operational control of Mari Gas field.