Karachaganak Field (, "Qarashyǵanaq munaı-gaz kondensat ken orny") is a gas condensate field about east of Aksai (Aksai) in northwest Kazakhstan. It was once a massive Permian and Carboniferous reef complex covering an area . At its largest point, the reservoir contains a gas column deep with a deep oil rim below it. It is estimated to contain of gas and one billion tonnes of liquid condensate and crude oil. Discovered in 1979, it began production under Karachaganckgazprom, a subsidiary of Gazprom. In 1992, AGIP (now Eni) and British Gas were awarded sole negotiating rights, forming a partnership company. In 1997, Texaco (now Chevron Corporation) and Lukoil signed a 40-year production sharing agreement with the original two companies and the Kazakhstan government to develop the field for world markets. The agreement was turned under a partnership company known as Karachaganak Petroleum Operating (KPO) where Royal Dutch Shell and ENI are joint operators with a 29.25% stake each in the company, and with Chevron and Lukoil owning 18% and 13.5% respectively. In September 2009