Karachaganak Field (, Qarashyǵanaq munaı-gaz kondensat ken orny) is a gas condensate field about east of Aksay (Ақсай) 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 Karachaganakgazprom, 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 the KPO filed an arbitration case against Kazakhstan. The Republic of Kazakhstan appointed Maksat Idenov to lead the negotiations, after which the arbitration was suspended towards an amicable settlement of the dispute and KazMunayGas engaged in entrance into the project in 2010. Under the terms of an agreement reached on December 14, 2011, the Republic of Kazakhstan has acquired through KazMunayGas a 10% stake for $2 billion cash and $1 billion non-cash consideration. History Located in the Uralsk Region of West Kazakhstan, it was discovered in 1979 by a well drilled to investigate a structural high detected during a reinterpretation of 2D seismic shot between 1970 and 1971. Production began in 1984 under the operatorship of Karachaganakgazprom. Limited quantities of gas and condensate were exported to Russia via pipelines and to the processing facilities at Orenburg. On 3 October 2006, Kazakhstan and Russia signed an agreement to create a joint venture on the basis of Orenburg gas processing plant for processing gas from the Karachaganak field. Phase 1 The phase began with three wells penetrating into the Permian formations of the reservoir. Once produced to surface the gas and oil were separated before being piped to Orenburg where further processing was undertaken. This was partially due to the sour nature of the gas, with a hydrogen sulphide content of 3.5-5.0% and carbon dioxide content of 5%. Karachaganckgazprom