The acquisition would give Exxon a dominant position in the oil-rich Permian Basin in West Texas and New Mexico.
Exxon Mobil Corp. (XOM) is nearing a deal to buy Pioneer Natural Resources (PXD) in a massive acquisition that could be valued at around $60 billion.
If there are no last-minute snags in the talks, a deal could be struck in the next few days, people familiar with the matter said.