In a statement on Friday, Comet announced that both partners had increased their stakes from 26% to 39% in the “highly prospective” project.

“The opportunity to strengthen the company’s position in the project emerged following a decision by AJ Lucas to withdraw from exploration and development activities in the USA,” Comet said.

“Comet Ridge and Strike Oil will continue working together towards identifying and capturing oil and gas opportunities in a four-state Rocky Mountain area of mutual interest.”

Only last week, Comet announced that the joint venture was about to start an 8 square mile (12.87 square kilometre) survey over a significant part of the project area that overlaps a smaller survey shot by its US partners in 2004.

Data from the survey is expected to provide critical subsurface view of fracture patterns that control oil production from the Pierre and Niobrara formations, Comet said.

It plans to use the directional drilling capability developed at Tow Creek to redevelop the field, which has produced about 15 million barrels of oil in its 144-year history.