RIO DE JANEIRO, June 22 (Reuters) - Consortia led by Brazil's 3R Petroleum Oleo e Gas SA and private equity firm Seacrest Capital have submitted binding offers for a refinery and dozens of oilfields owned by state-run Petrobras, three people familiar with the matter told Reuters.

Polo Potiguar is expected to fetch Petroleo Brasileiro SA from several hundred million dollars to over a billion dollars, two sources said. Petrobras is selling dozens of non-core assets to reduce debt and focus on deepwater oil production, and asset sales have picked up after slowing sharply during the pandemic in 2020 and early 2021.

Rio de Janeiro-based Grupo Verde Brasil (GVB) and Houston-based B-in Partners have joined the 3R-led bid for the assets, known collectively as Polo Potiguar, the sources said.

Seacrest submitted a bid alongside Brazil's Global Participações em Energia, which operates power plants in the nation's northern and northeastern regions, added the sources, who requested anonymity to discuss confidential matters.

The bids, due on June 11, have not been previously reported.

Petrobras, 3R, GVB and B-in declined to comment.

Seacrest and Global did not respond to a request for comment.

Petrobras announced in August it was putting Polo Potiguar, located in the northeastern state of Rio Grande do Norte, up for sale. The asset includes 23,000 barrels per day (bpd) of onshore and shallow-water oil production, according to 2020 bidding documents. It also includes the Potiguar Clara Camarao Refinery, which has installed capacity of 39,600 bpd.

It was not clear if any other consortia bid for the assets. Grupo Cobra, a subsidiary of French infrastructure group Vinci SA, participated in earlier phases of the sale process, but it was not clear if they submitted a binding offer.

Cobra did not respond to a request for comment.

If Petrobras finds any bids for Polo Potiguar suitable, it will likely begin bilateral talks with the winning consortium within days or weeks, the sources said. (Reporting by Gram Slattery Editing by Brad Haynes and David Gregorio)