The company said this week in a presentation on its website that the decision on expanding the Tengiz development in Kazakhstan will be made in mid-2016. Installing 4,500 camp beds for construction crews is done and port dredging 25 percent complete, it said. The project may cost as much as $40 billion and add crude supply equivalent to that of Libya. The investment was put on hold last year after cost estimates ballooned amid plunging oil prices.

The Kashagan oilfield development project has been marred by delays and cost overruns. It first began producing in September 2013 but was halted two weeks later due to gas leaks.

Kazakhstan's KazMunaiGaz, which owns the largest stake in the project, has said previously that the field would relaunch by the end of 2016.

Kazakhstan's vast Kashagan oil field, the world's biggest oil find in decades, is expected to restart production at the end of 2016, Exxon Mobil Production Vice President John Chaplin said.

The transaction is ostensibly intended to help energy company KazMunayGaz (KMG) reduce its $20 billion debt portfolio, which has been exacerbated by low oil prices.

China, Kazakhstan to sign $10 billion in deals including oil, infrastructure

The cost of Kashagan, already the world’s most expensive oil project, is set to rise by nearly $4bn as the companies developing it are forced to replace 200km of leaking pipelines.

Investors flocked to Kazakhstan’s first dollar-denominated bond in more than a decade, the first sovereign bond deal to include terms created in response to Argentina’s acrimonious default.

KazMunaiGas Seeks to Take Exploration Subsidiary Private KMG Officials Have Been Looking to Reintegrate the Subsidiary for Years

Italy's Eni grows Kazakh footprint with new offshore deal