Karachaganak Gas: A Resource in the Kazakh Steppes

Galloway, Ian F., BG-Group, Reading, United Kingdom

The Karachaganak oil-gas-condensate field, located in the Western Oblast of Kazakhstan, was discovered in 1979 and has original hydrocarbon in place reserves of 48.4TCF of gas and 9.6 billion barrels of liquids. Under the Soviet administration the field was brought into production in 1984 sending gas and partially stabilised liquids to Orenburg in Russia. A Production Sharing Agreement, signed in 1997, between the Republic of Kazakhstan, BG-Group and Eni (as joint operator), ChevronTexaco and Lukoil has lead to significant further development of the field.

Liquids and Gas sales to Orenburg have continued since 1997, supplemented by addi­tional facilities commissioned in 2004 which deliver Karachaganak liquids through the CPC pipeline to Novorissiysk on the Black Sea. To maintain the pressure of this retrograde gas condensate reservoir, 40% of produced gas is reinjected, requiring one of the highest pres­sure sour gas reinjection schemes in the world. The paper will discuss some of the techni­cal challenges associated with operating the reinjection scheme.

A key value driver is to deliver increased volumes of liquids over a significant plateau period to Western Markets. To achieve this, increasing volumes of gas, arising from the nat­ural growth in gas-liquids ratio as the reservoir depletes, have to be handled. This will be managed by the drilling of horizontal wells into lower sections of the reservoir, by increased gas injection and by expansion of gas sales. The paper will review these issues and the chal­lenges to maximise the value of the field’s gas resources.