Exxon Mobil said Monday changes in oil prices would increase the company's second-quarter upstream earnings by $300 million to $700 million compared with the first quarter.

The oil major would be reporting its first earnings after closing the acquisition of Pioneer Natural Resources for $60 billion, with the combined operations making it the largest oil producer in the Permian basin.

Exxon, however, said it expects changes in gas prices to decrease its quarterly upstream earnings by $300 million to $700 million compared with the first quarter.

The largest U.S. oil producer had posted $5.7 billion in upstream earnings for the first quarter ended March 31.