HOUSTON/RIO DE JANEIRO (Reuters) - Chevron Corp CVX.N has held talks to acquire Pasadena Refining System Inc (PRSI), a Texas oil refining unit of Brazilian state-run oil firm Petroleo Brasileiro SA PETR4.SA, three people familiar with the matter said this week.

FILE PHOTO: The logo of Chevron (CVX) is seen in Los Angeles, California, United States, April 12, 2016. REUTERS/Lucy Nicholson/File Photo

U.S. oil companies are looking to expand refining operations to handle rising volumes of crude flowing from the country’s shale fields. A deal for PRSI would give Chevron an oil refinery that can process about 110,000 barrels-per-day of light crude.

Chevron is also discussing a gas liquids processing joint venture with Kinder Morgan Inc KMI.N, largest energy infrastructure provider in North America, two of the sources said. Kinder Morgan operates a nearby plant that separates gas liquids into ethane, propane and other fuels.

The sources requested anonymity to discuss the confidential talks. They did not disclose the deal price.

Petrobras did not respond to requests for comment.

Chevron and Kinder Morgan declined to comment.

Petrobras, which is deeply in debt, has been seeking to divest $21 billion in assets by year-end but has faced union resistance and legal obstacles. A presidential election on Sunday could raise obstacles for a sale with front-runner Jair Bolsonaro promising to install new managers at the company.

The PRSI refinery has been limited in the type of crude it can run since a 2011 fire, which left one of its processing units idle. A buyer would have to invest to upgrade the refinery, one of the people familiar with the matter said. But PRSI includes open land that could enable a future owner to easily expand the plant.

Petrobras put the plant, which is on the Houston Ship Channel leading to the U.S. Gulf of Mexico and has its own export docks, on the market earlier this year after sinking more than $1.18 billion into the operation since 2006.

Garfield Miller, chief executive of energy investment bank Aegis Energy Advisors, said the U.S. shale-oil boom has given a second chance to U.S. plants designed to process lighter crudes. Several years ago Petrobras would not have been able to sell PRSI because of its age and inability to process heavy crudes, he said.

That has changed with the growth of the Permian Basin, the nation’s largest oilfield, which now produces 3.5 million barrels per day of oil, according to U.S. government figures.

“Anyone with crude in the Permian might logically want to own it,” said Miller. “This refinery today has value, whereas eight or nine years ago it had none.”

Pierre Breber, Chevron’s head of refining and chemicals, this month said the company wanted to build or buy a refinery along the U.S. Gulf Coast to process oil from its West Texas operations.

Chevron’s shale output from the region jumped 51 percent in the second quarter to 270,000 barrels of oil equivalent per day. By expanding its refining capacity to Houston, it would be able to process the crude closer to where it is produced.