Diamondback Energy Inc. is closing in on a deal to acquire closely held West Texas oil producer Double Eagle in a bid to further its dominance in the world’s biggest shale patch, according to people familiar with the matter.

Diamondback Energy, a major player in the shale oil industry, has announced its acquisition of certain units of Double Eagle Energy.

Diamondback Energy said on Tuesday it would buy certain units of EnCap Investments-backed energy producer Double Eagle in a cash-and-stock deal for about $4.08 billion, as the shale producer looks to expand its presence in the oil-rich U.

Diamondback Energy Inc. will expand its oil assets in the Permian Basin after agreeing to acquire some subsidiaries of Double Eagle IV Midco LLC, a significant asset boost for the top independent oil and gas producer in North America’s most prolific shale patch.