Five of the top oil and natural gas producers in the world last week failed to impress with their 2Q2013 earnings reports, with Royal Dutch Shell plc causing the most talk after it wrote off more than $2 billion on the value of some liquids-rich properties in North America.

The profits reports for ExxonMobil Corp., BP plc and Chevron Corp. also were nothing to write home about. Now, ExxonMobil has decided to cut back on its share buybacks, while Shell has launched a strategic review of its North American portfolio. BP’s Macondo compensation fund, meanwhile, is about to run dry. Chevron, meanwhile, is looking for equity partners in KM LNG, the gas export project in British Columbia, in which it partners 50-50 with Apache Corp.

The top news was Shell’s decision to begin a strategic review of its North American portfolio, which could result in the sale of as much as half of its nine main unconventional natural gas and oil assets, CEO Peter Voser said. Shell already had abandoned plans this year to drill offshore in Alaska, which has further cut into the outlook.

“We are not targeting oil and gas production volumes; rather we are focusing on financial performance,” Voser said. Shell had set a target to increase oil and gas output to 4 million boe/d by 2017-2018. That target now has been “retired.” Shell CFO Simon Henry told analysts that the “production curve is less positive than we originally expected.”

The writedown doesn’t mean that Shell has soured on North America’s unconventionals, said the CEO. “I think the liquids-rich shale development in North America in general is progressing well,” and the reduction in the value of some assets only reflects the higher risks involved in developing the portfolio, Voser said.

The writedown reverberated across the second quarter report and was the primary cause of a 60% decline from year-ago profits. The current cost of supplies, a figure used by European producers that excludes gains/losses from inventories and is equivalent to U.S. net profit figures, totaled $2.39 billion (27 cents/share) in 2Q2013, versus $5.98 million (66 cents) in the year-ago period. Excluding one-time charges, Shell earned $4.6 billion, still 20% off year/year. Group revenues fell to $112.67 billion from $117.07 billion.

Chevron and Apache are looking for equity partners to support KM LNG, which would export up to 1.4 Bcf/d to overseas markets, Chevron upstream chief George Kirkland said Friday. The project doesn’t expect its Canada gas to link to Henry Hub prices.

“We expect the equivalent value will come in an equity sell-down. We expect to have partners and buyers to offer volumes to, and we think that’s better than Henry Hub pricing…Henry Hub, like any index, has variability, which means it can go up or down. We believe we can get the same or better situation for buyers with their participation…equity in the project…We can do that because Apache and Chevron hold 50% each. We hold very strong interests in the resources so we have the ability to move that way. Our goal is to maintain our first-mover advantage, but at the same time move the project at the right speed.”

A final investment decision on KM is likely in 2014. “After having done all of the appropriate technical work, all of the commercial work, then we can get down to getting a sale for 60-70% of the position,” said Kirkland. “We’ve had some initial discussions with Asian partners, but we will not disclose the ones we are talking to at this time.”

Chevron also is expanding drilling plans in the Permian Basin, as well as the Marcellus Shale. Net production in the United States of 659,000 boe/d was flat from a year earlier. Production increases in western Pennsylvania, the Delaware Basin in New Mexico and at Perdido in the Gulf of Mexico were offset by normal field declines elsewhere, it said. The net liquids component of oil-equivalent production decreased 1% to 455,000 boe/d, while net natural gas production increased 3% to 1.23 Bcf/d.

Chevron reported a quarterly earnings decline of 26% y/y on higher costs and softer markets for its refined products. U.S. natural gas prices rose, but Chevron’s production is weighted to oil. Profits totaled $537 billion ($2.77/share), compared with $7.21 billion ($3.66) in the year-ago period. Revenue declined more than 8% to $57.37 billion. U.S. upstream earnings were $1.08 billion, down y/y from $235 million.

ExxonMobil CEO Rex Tillerson claimed that the latest quarter reflected a “continued strong operation performance,” but it was generally hit-and-miss. Profits in 2Q2013 totaled $6.9 billion ($1.55/share), versus year-ago earnings of $15.9 billion ($3.41). Revenue declined 16% to $106.5 billion.

ExxonMobil Senior Vice President David Rosenthal, who led a conference call Thursday with analysts, faulted “constrained” global economic growth and a “sluggish” U.S. economy as two reasons for the downturn in profits. However, the company is moving forward with two North American liquefied natural gas export projects in Canada and the Texas Gulf Coast and possibly could a third one in Alaska, he said.

ExxonMobil’s biggest U.S. onshore development continues to be the liquids-rich Ardmore Basin in south-central Oklahoma, home to the Woodford Shale. Gross operated production there reached 31,000 boe/d in 2Q2013, 73% higher year/year. There’s also strong performance in the Marcellus Shale. All of the onshore is benefiting from drilling efficiencies and a move to pad drilling.

BP also didn’t fare so well in the latest period, but it was more about the three-year-old Macondo blowout in the Gulf of Mexico (GOM). Group CEO Bob Dudley said last week the $20 billion fund that was set up to cover the well blowout costs soon will run out as compensation claims, many of which management believes are fraudulent, continue to accelerate.

The higher litigation costs proved that the 2010 tragedy still is festering and chewing into the supermajor’s bottom line. The London-based producers replacement cost profits declined year/year to $2.4 billion from year-ago earnings of $3.6 billion and from 1Q2013 earnings of $4.6 billion. Earnings from operations fell 24% to $2.71 billion.

BP raised its estimate that it has paid or is committed to paying under the Macondo settlement process by $1.4 billion to $9.6 billion, bringing the cumulative charges for items covered under the trust fund to $19.7 billion at the end of June. The fund likely will be depleted by the end of September, Dudley said. At that point, BP would have to take additional charges to its income statement.

Dudley tried to put a brave face on the company’s woes and said the company is “seeing growth in production from new high-margin projects and…making good progress in exploration and project delivery.” However, total U.S. liquids production, about half of which comes from the GOM, has posted a year/year decline in every quarter since the April 2010 spill. U.S. output of 335,000 boe/d in the quarter was its lowest level in 15 years.