Occidental Petroleum said adjusted loss attributable to common stockholders was $136 million, or 15 cents per share, for the March quarter, compared with a loss of $610 million, or 65 cents per share, in the fourth quarter.
Company attributes the first-quarter loss to halting work on the Keystone XL pipeline.
Rising oil prices have sparked optimism for EOG Resources and other shale producers after enduring a year of destruction in the oil markets, with WTI futures in the U.S gaining 23% in the first quarter.
Exxon Mobil, the biggest U.S. oil producer, has slashed costs, delayed projects and said it could trim an estimated 14,000 employees globally, or 15%, including contractors.
The swing to profit in the first quarter also comes as Marathon Oil and other shale producers slashed spending and production last year.
Pioneer Natural Resources, which operates in the Permian Basin in West Texas, said that its total output was 474,000 boe/d in the first quarter, compared with 364,000 boe/d of production in fourth-quarter 2020.
ConocoPhillips said it sold its oil and gas for an average $45.36 per barrel during the quarter, 17% higher than the year-ago period.
The company posted quarterly production of 307,422 barrels of oil equivalent per day (boe/d), 2.8% higher than the previous quarter.
Chevron reported a profit of $1.72 billion, or 90 cents per share, compared with $2.45 billion, or $1.31 per share, a year earlier.