U.S. energy company ConocoPhillips said it was trimming its capital spending program for 2015, with funding targeting U.S. shale basins down 20 percent.

"The reduction in capital relative to 2014 primarily reflects lower spending on major projects, several of which are nearing completion, as well as the deferral of spending on North American unconventional plays," the company said.

Conoco said it was cutting its capital budget for 2015 to $13.5 billion, a decline of about 20 percent from the level for this year.

Several so-called supermajors have trimmed their spending programs because crude oil prices have shed about 30 percent of their value since June. The price for West Texas Intermediate, the U.S. crude oil benchmark, is at a point where some drillers might not generate a profit from shale basins in the United States.

"We are setting our 2015 capital budget at a level that we believe is prudent given the current environment," Conoco Chairman and Chief Executive Officer Ryan Lance said in a Monday statement.

The company still plans to spend 35 percent, or about $5 billion, of its capital next year on drilling programs in the Eagle Ford, Bakken and other shale plays in the United States. That's approximately 20 percent less than allocated this year for U.S. shale basins.

Bakken oil production is holding steady at around 1 million barrels per day, despite lower oil prices. A report from North Dakota later this week could be indicative of the level at which premier shale basins are profitable during the bear market for crude oil.

Eagle Ford is one of the most prolific shale basins in the United States. A report from energy consultant group Wood Mackenzie found enhanced oil recovery, a pioneering extraction method for shale basins, could add between 1.5 million and 3 million barrels per day in oil production by 2030.

Conoco said it has the flexibility to "ramp up or down" its operations in U.S. shale basins.

About $1.8 billion is designated for exploration and appraisal programs in the Gulf of Mexico, West Africa and Nova Scotia.