Sunoco Inc. (SUN) cut its dividend in half and said it would shut a New Jersey refinery indefinitely, shifting its production to two nearby sites.

Both actions, taken because "the operating environment continues to be very poor," are expected to save the big oil refiner a total of $320 million a year.

Sunoco, the second-largest U.S. independent oil refiner by volume after Valero Energy Corp. (VLO), has been cutting costs and is trying to sell its chemicals operations as the recession cuts demand.