* Blocks hold around 200 million barrels of oil - sources
* Chevron the latest oil major to sell Nigerian assets
* Oil theft, delayed energy law create uncertainty
By Joe Brock
ABUJA, June 11 (Reuters) - U.S. energy firm Chevron is selling its stake in two Nigerian shallow water oil blocks,the company said on Tuesday, the latest oil major seeking todispose of assets in Africa's biggest oil producer.
The two blocks OML 83 and OML 85 hold an estimated 200million barrels of oil and an unknown amount of natural gas butthere has been no production yet, two industry sources toldReuters. Chevron did not give details of reserves.
"As part of a continuous process of portfolio evaluation andbusiness prioritisation, Chevron Nigeria Limited ... hasput forward its interests in two oil mining leases for auction,"a company spokesman said.
"The assets are located in the shallow waters."
Chevron owns a 40 percent stake in 13 shallow water blockswith Nigeria's state oil firm NNPC and also has several deepoffshore assets. Its 2012 net daily production in Nigeriaaveraged 238,000 barrels of crude oil and 165 million cubic feetof natural gas.
Several oil majors have sold assets onshore or in theshallow waters of the Niger Delta over the past few years.
Nigeria suffers from widespread oil theft and at timesdifficult relationships with local communities onshore, drivingup the costs of operating there, while a long-delayed energybill is stuck in parliament, adding to industry uncertainty.
Joint owners Royal Dutch Shell, Italy's Eni and France's Total have sold several blocks.
Buyers of these included UK-listed firms Heritage Oil and Eland Oil. Chinese-owned Addax has said itis interested in buying more Nigerian assets.
Chevron's blocks are at the exploratory stage, unlikeShell's already producing fields, which will make valuationsless straightforward, one banking source said.
U.S. firm ConocoPhillips is also planning to sellits Nigerian businesses to Oando Energy for about $1.79billion, the company said in December.
Oil majors, which are looking more towards deepwateroffshore, say they can't invest in large new projects until theoil bill is passed.
