The 20-month feud between the Western Hemisphere’s two most powerful oil companies over the biggest offshore discovery in a generation hinged on a single clause of a contract few people have ever seen.

Longtime shale boss and North Texas energy magnate Scott Sheffield said he’s no longer interested in joining Exxon Mobil Corp.’s board after the U.S.

Former Pioneer Natural Resources CEO Scott Sheffield told Hart Energy, “For now, I remain one of Exxon’s largest individual shareholders and as such will consider other options.”

Chevron has prevailed against Exxon Mobil in a dispute over Hess Corporation’s offshore oil assets in the South American nation of Guyana.

The FTC has reopened an order involving Chevron’s proposed acquisition of Hess, and another regarding Exxon Mobil’s proposed purchase of Pioneer Natural Resources after its initial complaints failed to plead any antitrust law violation.