By Raushan Nurshayeva

ASTANA (Reuters) - Kazakhstan and a group of oil companies led by Chevron have approved a $36.8 billion plan to boost production at the Central Asian country's Tengiz field, a rare major investment in an industry hit by low prices and a boost to the local economy. 

The field, one of the world's biggest, already accounts for more than a third of total crude output in Kazakhstan, which is the biggest former Soviet oil producer after Russia. 

Under the plan, Tengiz, in which Exxon Mobil and Lukoil also have stakes, will increase output to 39 million tonnes a year (850,000 barrels per day) by 2022 from 27 million tonnes currently, Kazakhstan's Energy Ministry and its foreign partners said in a joint statement on Tuesday.  MORE