The two focused on expanding oil and gas production as rivals BP and Shell spent heavily on wind, solar and renewables that have yet to pay off. Both U.S. oil firms have meanwhile benefited from acquisitions of smaller oil producers.

Still, their surging production could soon face a challenge from uncertain demand, especially in top oil importer China, and the potential for OPEC to lift production curbs as soon as next month. The group is expected to delay a plan to add 180,000 barrels per day amid concerns over weak demand and oversupply.

Exxon pumped a record 4.6 million barrels of oil equivalent per day (boepd) in the third-quarter, up more than 24% from a year-ago, as its $60 billion bet on Pioneer Natural Resources and purchase of Denbury paid dividends.

Chevron, whose $53-billion takeover of Hess has been held up, posted a 7% increase in third-quarter output to 3.36 million boepd, mostly from gains in its U.S. shale business which pumped a record 1.61 million boepd. It added a drilling rig in the Permian basin last quarter and will begin a production expansion in Kazakhstan next quarter.

Both companies reported lower year-over-year profits as weak global refining margins that hit BP and TotalEnergies hard and also cut their oil earnings. Exxon's third-quarter profits were 5% lower than last year, while Chevron's fell 21%.