BP Plc said it completed the sale of its Prudhoe Bay oil and gas producing properties to closely-held Hilcorp Energy Co., ending 60 years as a top Alaskan oil producer.

BP and other oil majors have reduced their production roles in the northernmost U.S. state as output slid and lower-cost fields emerged elsewhere. Hilcorp, known for buying up oil castoffs, acquired half of another BP Alaska project in 2014.

The $5.6 billion deal, including BP's stake in the Trans Alaska Pipeline System which carries crude oil from Prudhoe Bay to Alaska's southern coast, should wrap up this quarter, both companies said in statements.

"We look forward to continuing to drive economic growth, create Alaskan jobs and contribute to local economies for decades to come,” said Greg Lalicker, CEO of Hilcorp Energy.

The agreement calls for Hilcorp to pay $4 billion to BP over an unspecified time, with the remaining $1.6 billion based on future earnings from the properties. Terms were revised and pushed back as Hilcorp sought to raise financing.

With the July 1 purchase, Texas-based Hilcorp becomes the state's second largest oil producer and reserves holder, behind ConocoPhillips Co. Hilcorp will nearly triple its workforce in Alaska, to 1,450 employees with the acquisition, said Luke Miller, Hilcorp spokesman.