Africa-focused oil and gas explorer Bowleven has achieved its much anticipated farm-out agreement on its Etinde Permit offshore Cameroon.The AIM-listed company has farmed out two thirds of its 75% stake in Etinde to Russia's Lukoil and private equity-backed explorer NewAge for $250m.In return for giving up 50% of the licence, Bowleven will get $170m cash on completion, $40m at the final investment decision (FID) stage, and $40m net carry on two wells.The size of the deal equates to a valuation of $210m net, which implies the company's retained 25% is worth $105m.NewAge will take over as operator of the project, which enables Bowleven to focus on its exploration acreage onshore Cameroon and in Kenya. Broker Westhouse said the deal was "very significant" as it "dramatically derisks" the company's main project, which the market had been applying a "paltry 15% chance of success"."The injection of cash means that Bowleven will have the resources to proceed with these exploration projects on a sole risk basis and the strengthened Etinde partnership suggests that the upside potential on Etinde," the broker said.The deal will end the company's strategic alliance with oil services provider Petrofac, with which Bowleven in 2012 agreed to provide as much as $500m for the oil and gas field development."The implications for the strategic alliance agreement are yet to be worked through," a Petrofac spokeswoman told Bloomberg. Shares in the company were up 9.4% to 43.5p at 13:20 on Tuesday. OH