BP Plc is in talks to buy a direct stake in an East Siberian oil producer from OAO Rosneft, the Russian oil producer facing U.S. and European financing bans, according to a person with direct knowledge of the matter.

The talks about Rosneft’s Tass Yuriakh unit started some time ago, according to the person, who asked not to be identified because the information isn’t public. The stake may be valued at $700 million to $800 million, according to Russian daily Kommersant, which reported the deal.

BP has remained committed to its partnership with Rosneft, in which it holds 20%, as Russia’s relations with the U.S. and Europe sour over the conflict in Ukraine. U.S.-led sanctions, which restrict Rosneft from borrowing internationally and limit access to offshore and shale technology, don’t stop it from selling assets.

BP has been seeking direct production ventures in Russia after selling its half of the TNK-BP venture to the state-controlled company last year. Rosneft’s and BP’s press services declined to comment on talks about Tass Yuriakh.

Output from the field, located near a pipeline to the Pacific coast, will be used to supply Far Eastern refineries and China, according to Rosneft’s website. Production will exceed 5 MMmt a year, or 100,000 bbl/d, in 2017, according to the statement. The East Siberian unit also holds 155 Bcm (5.5 Tcf) of natural gas reserves, according to the website.

President Vladimir Putin is pushing to boost energy supplies to Asian markets from East Siberia to lower Russia’s dependence on Europe and maintain demand for oil and gas, which contribute half of the government’s budget.

Russia has held discussions on developing Tass Yuriakh with China National Petroleum Corp. The unit was intended to be the base for formation of a Russian E&P venture with the Chinese company, according to a statement on Rosneft’s website dated Oct. 18, 2013.

BP’s participation in the development would reduce the risk of delays and ease the burden on Rosneft as it integrates other recently purchased assets and businesses, according to a research note by Sberbank analysts Alex Fak and Valery Nesterov.

“This removes at least one source of concern for a company that has spread itself too thinly over the past couple of years,” they wrote. Rosneft net debt reached $45 billion at the end of the third quarter, according to a presentation on the company website.