By David French

(Reuters) - U.S. shale oil and gas producers Oasis Petroleum Inc and Whiting Petroleum Corp are close to agreeing an all-stock merger that could be announced as soon as this week, a source familiar with the matter said on Sunday.

The combined value of the two companies would be around $6.07 billion, according to Reuters calculations based upon Friday's closing prices, which valued Oasis at $2.80 billion and Whiting at $3.27 billion.

The person with knowledge of the matter spoke on condition of anonymity in order to discuss private information.

The deal talks between the pair, which both operate in the Bakken shale formation of North Dakota, come amid a significant spike in crude oil prices on the back of the Russian invasion of Ukraine.

Both Brent and U.S. benchmarks temporarily hit their highest levels since 2008 as trading began the week in Asia, as the United States and European allies mulled a Russian oil import ban in response to the conflict, which Russia calls a "special operation". [O/R]

The Wall Street Journal had earlier reported the talks between Oasis and Whiting.

Oasis Petroleum and Whiting Petroleum did not immediately respond to a request for comment.

Both companies filed for Chapter 11 bankruptcy in 2020 after the energy industry reeled under an unprecedented crash in oil prices due to the COVID-19 pandemic, with Whiting the first publicly traded shale producer to file for bankruptcy when it did so in April of that year.

Last year, oil and gas pipeline operator Crestwood Equity Partners LP said it would buy Oasis Petroleum's midstream unit in a $1.8 billion deal.

(Reporting by David French in Houston and Abinaya Vijayaraghavan in Bengaluru; Editing by Kenneth Maxwell)