United States-based energy corporation, Chevron has again put up for sale its stake in two Nigerian offshore oil and gas blocks, a sale document seen by Reuters News Agency showed, as the company seeks to dispose of aging assets to focus on its fast-growing production in the United States.

The two businesses are shallow-water Oil Mining Lease (OML) 86 and OML 88. Chevron will be selling its 40 per cent stake in the businesses.

The two businesses produce approximately 6,200 barrels of oil equivalent per day, according to the sale document.

The sale is also part of a broader retreat by international oil companies from Nigerian oil and gas fields that have been plagued by pipeline theft as well as uncertainty over the West African country’s tax regime.

The company has hired Scotiabank to run the sale process.

“Chevron Nigeria Limited (CNL), operator of the joint venture between the Nigerian National Petroleum Corporation and CNL, continuously evaluates its portfolio of assets in the country including Oil Mining Leases (OMLs) 86 and 88, as well as emerging opportunities in order to optimize its business,” spokesman Ray Fohr said in a statement.

“Over the years, CNL has received unsolicited expressions of interest from companies who are desirous of acquiring CNL’s interest in OMLs 86 and 88. CNL is currently revalidating their interest before determining next steps with respect to commencing a possible divestment process,” Fohr added.

Scotiabank declined to comment.

Chevron tried and failed to sell the two blocks in 2015 when global deal-making in oil and gas dropped sharply following a collapse in oil prices the previous year.

OML 86 and 88 contain 55 million barrels of yet-to-be exploited oil barrels and 79.3 billion cubic metres (2.8 trillion cubic feet) of undeveloped gas reserves, the document said.

Foreign oil companies including Chevron, Royal Dutch Shell and Exxon Mobil have retreated in recent years from onshore and shallow-water production in Nigeria due to oil theft, selling assets mostly to local companies.