Major U.S. oil and gas companies will begin reporting their quarterly earnings this week, and the results are not expected to be pretty.

As the crude oil-price slump heads into its second year, energy firms are likely to see multibillion-dollar declines in profits and revenue, which could prompt further cuts in investments and personnel amid the sharpest decline in oil prices in decades.

An oversupply of crude and sluggish demand growth in emerging markets helped push U.S. oil prices down to a near 13-year low during the first quarter of 2016. Thousands of American oil and gas extraction jobs have disappeared in recent months as companies continued slashing costs and postponing new projects. The number of U.S. drilling rigs, one measure of oil and gas activity, declined nearly every week in the first three months of the year, Baker Hughes Inc. reported.

Oil company executives have insisted their firms can ride out the downturn through aggressive cost-cutting and more efficient operations.

British oil giant BP Plc (NYSE:BP), for example, said Tuesday it might slash capital spending further this year to $17 billion after reporting its second consecutive loss in quarterly earnings. Profits plunged 80 percent to a pretax loss of $485 million in the first quarter on falling commodity prices and continued costs tied to its 2010 Deepwater Horizon oil spill disaster.

As oil companies scale back operations, the U.S. is starting to produce less crude oil. The U.S. produced an estimated 8.9 million barrels a day for the week ending April 15, a drop of more than 3 percent since the start of the year, U.S. Energy Information Administration data show. Global oil supplies similarly nudged down slightly in March to 96.1 million barrels a day on falling production in other major oil-producing nations, the International Energy Agency estimated.

The decline in crude output could help rebalance oil markets later this year, boosting the bottom line for oil companies. U.S. crude prices have already moved higher in recent weeks to above $40 a barrel, and the S&P 500 energy sector has gained nearly 10 percent this year — making it the second-best performing industry in the index.

Still, the second quarter isn’t expected to be much brighter for oil companies than the first, said Paal Kibsgaard, chairman and CEO Schlumberger Ltd (NYSE:SLB). The Houston oilfield services giant on Tuesday reported a 63 percent year-on-year drop in net income, excluding charges and credits, to $501 million.

“The environment is expected to continue deteriorating over the coming quarter given the magnitude and erratic nature of the disruptions in activity,” he said in a statement.  

The U.S. oil and gas giants reporting first quarter earnings this week include ConocoPhillips (NYSE:COP), Exxon Mobil Corp. (NYSE:XOM), and Chevron Corp. (NYSE:CVX). Here's what to expect from each company.

ConocoPhillips Co.

The Houston energy exploration and production company said it will report earnings before the market opens Thursday. ConocoPhillips in the fourth quarter delivered a larger-than-anticipated loss and cut its dividend by two-thirds.

For the first quarter, the company is expected to report a loss of 98 cents per share, down from earnings of 22 cents per share in the first three months of 2015, according to analysts polled by Thomson Reuters. Using non-GAAP accounting, the company’s loss could reach $1.05 per share, versus a loss of 18 cents per share a year ago.

Analysts said they expected ConocoPhillips to report first-quarter revenue of $7.9 billion, down from $8.6 billion in the first three months of 2015. The Texas energy giant could report a pretax profit loss of $1.6 billion in the first quarter, versus a profit loss of $365 million a year ago.

Exxon Mobil Corp.

The No. 1 U.S. oil producer said it will report first quarter earnings before the opening bell on Friday. Exxon’s longtime pristine credit rating was tarnished earlier this week after Standard & Poor’s downgraded the company, citing the punishing global oil market and the high costs of maintaining oil operations.

S&P analysts ended Exxon’s 86-year-streak of perfect AAA ratings Tuesday and notched the company’s credit rating to AA+. Exxon’s high dividend and share buyback spending also factored into the credit agency’s decision.

Analysts polled by Thomson Reuters said they expected the Irving, Texas-based behemoth to report earnings of 29 cents per share and non-GAAP earnings of 31 cents per share in the first quarter, down from earnings of $1.17 per share for both measures in the year-ago period.

Exxon’s revenue in the first quarter could drop by nearly one-third to $45.4 billion, compared to revenue $67.6 billion in the first three months of 2015. Pre-tax profit could shrink to $2.6 billion in the first quarter this year from $6.6 billion last year.

Chevron Corp.

The San Ramon, California-based oil producer and refiner said it will report earnings for the period on Friday morning. Chevron, America’s No. 2 oil producer, swung to a loss in the fourth quarter for the first time in more than 13 years as plunging oil prices hammered profitability across all divisions.

The company this week is expected to report a loss of 16 cents per share for the quarter, down from earnings of $1.37 a share last year, the Thomson Reuters analyst survey showed. Under non-GAAP accounting, the company could see a loss of 15 cents per share, compared to earnings of 76 cents per share for the first quarter 2015.

Chevron’s quarterly revenue could slide nearly 40 percent to $21.4 billion, from $34.5 billion in the same period a year ago. The company could report a pretax profit loss of $143.8 million in the first quarter, down from $1.7 billion in profit last year.