Energy companies that have long been known for hefty profits are now forced to cut investments around the world. Rystad Energy, a consulting firm based in Norway, has estimated that the cuts will amount to $180 billion in 2015 alone. That has brought tens of thousands of job losses, which are beginning to hurt the economies of energy-rich states like Louisiana, North Dakota, Oklahoma and Texas.

Some of the cuts in spending by Exxon, Chevron and other companies result from lower payments to service companies, which must lower their rates for well drilling and completions as exploration activity declines. Other cuts come in high-cost fields, like Canada’s oil sands and deepwater offshore projects. But Exxon and Chevron are still pressing ahead in promising oil and gas fields in several countries, including the United States and Australia.

Chevron’s net income fell severely in the second quarter to $571 million, from $5.67 billion in the same quarter a year ago. Revenue fell to $40.4 billion, from nearly $58 billion a year ago. Over the first six months of the year, Chevron cut its capital and exploratory expenses to $17.3 billion, from $19.6 billion, over the first half of 2014.

Its oil and gas production businesses actually lost money, $2.22 billion, in contrast to earning more than $5 billion in the year-ago quarter. The company announced a write-down on assets of $1.96 billion. This week the company said it would cut 1,500 jobs as part of an effort to reduce costs by $1 billion.

“Our upstream businesses were particularly hard hit,” said Chevron’s chief executive, John Watson, “as lower prices reduced revenues and triggered impairments and other charges.” He added, “Multiple efforts to improve future earnings and cash flows are underway.”

There was some good news in the Chevron results. Earnings from its refinery businesses, which make gasoline, lubricants, diesel and other refined products, were lifted by stronger margins to nearly $3 billion from $721 million in the year-ago quarter. Also, production of oil and gas was up 2 percent because of new or stepped-up operations in Argentina, Bangladesh and the Permian basin in West Texas.

Nevertheless, analysts expressed disappointment.

“Second-quarter earnings were lower than expected for both companies, a disappointment for Exxon and a disaster for Chevron,” said Fadel Gheit, a senior oil company analyst at Oppenheimer & Company. “Both lost money in the U.S., especially Chevron.”