Challenger is the oil and gas subsidiary of GlobalSantaFe, one of the world’s largest drilling contractors and is listed on the New York Stock Exchange with a market capitalisation of about $US16 billion, according to Rialto.

“CMI is a highly focused and experienced screener of offshore oil and gas prospects worldwide, delivering risk-managed energy solutions for the benefit of its joint venture participants and to asset owners,” Rialto said.

“CMI has successfully deployed this business model and currently holds interests in about 70 oil and gas properties worldwide.”

The amended agreement with Challenger gives Rialto a guaranteed right for the next three years to an increased level of participating interest as a joint venturer in a range of exploration, development or production opportunities.

It also provides access to offshore drilling expertise and drilling management services. This will significantly enhance the company’s ability to deliver on projects in the tightly constrained drilling services market, Rialto chief executive Brett Woods said.

“Through the relationship we are seeing a range of first-class, low-risk appraisal opportunities with near-term drilling potential coupled with the ability to deliver drilling services at a time of extremely tight rig market conditions,” Woods said.

“We are so confident that the relationship will provide Rialto with a substantial platform for growth that we have seized the opportunity to significantly increase our participation in the new projects that we are considering.

“We are now working as a priority on securing the most attractive projects.”