Spanish energy company Repsol said it was offering up a portion of its holdings in a U.S. shale basin in favor of a position in operations offshore Norway.

Repsol divested 13 percent of its stake in the Eagle Ford shale basin in the United States to its Norwegian counterpart Statoil in exchange for a 15 percent share in the Gudrun field off the coast of Norway. The transaction is cash-neutral.

Aside from the swap, the Spanish energy company said both sides agreed to set up operations in the Eagle Ford basin under a single umbrella with Statoil serving as the operator.

"That will help ensure operations become more efficient, through optimal field developments and cost savings, and thus more resilient to low oil prices," Repsol said.

Lower crude oil prices, off about 40 percent from this time last year, means energy companies are spending less on exploration and production. That, in part, has led to a decline in output in all but a few shale basins in the United States.

A drilling productivity report from the U.S. Energy Information Administration finds production in the Eagle Ford shale basin may decline 6 percent by January to 1.2 million barrels per day.

Repsol retains a 37 percent stake in the Eagle Ford project.

Gudrun became Statoil's first new operation on the Norwegian continental shelf in nearly a decade when it started operations last year. Gudrun should produce up to 184 million barrels of oil and gas equivalent over its lifespan.