The Tengizchevroil (TCO) joint venture has developed the Tengiz field since 1993. The major partners in Tengizchevroil are Chevron (50% ownership), Exxon/Mobil (25% ownership), the Kazakhstani government through KazMuniGaz (20% ownership) and Russian LukArco (5%).

 

Estimated at up to 25 billion barrels (4 km³) of oil originally in place, Tengiz is the sixth largest oil field in the world; recoverable crude oil reserves have been estimated at 6 to 9 billion barrels (0.9 to 1.4 km³). Like many other oil fields, the Tengiz also contains large reserves of natural gas. Since the oil from Tengiz contains a high amount of sulfur (up to 17%), an estimated 6 million tons of sulfur byproduct were stored in the form of large sulfur blocks as of December 2002. At the time, about 4000 tonnes a day was being added. On October 3rd, 2007, the Kazakh environment ministry was reported to be considering imposing fines against TCO for alleged breaches in the way the sulfur is stored.

 

In 2002, TCO produced 285,000 barrels (45,000 m³) per day, or one third of Kazakhstan's daily production. In January 2003, after contentious negotiations with the government of Kazakhstan, the TCO consortium members initiated a $3 billion expansion project designed to boost production to approximately 450,000 barrels (72,000 m³) per day by 2006. According to Chevron, Tengiz could potentially produce 700,000 barrels (111,000 m³) per day by the end of the decade.

 

An area of major geopolitical competition involves the routing of oil out of this oil field. Oil from the Tengiz field is primarily routed to the Russian Black Sea port of Novorossiysk through the Caspian Pipeline Consortium (CPC) project. The Baku-Tbilisi-Ceyhan Pipeline is a competing pipeline put forth by U.S. interests to bypass dependence on the Russian pipeline.