AIM-listed oil and gas exploration group Bowleven has entered into a farm-out drill-to-earn arrangement with Africa Fortesa Corp (AFC).AFC will earn a 20% interest in the group's Bomono Permit in return for drilling two exploration wells.Based on the terms of the arrangement, the cost of the two-well programme, which does not include testing, is estimated to be around $13 - $15m. Drilling at the Cameroon site is expected to begin before the end of 2014.As of 10:06 the share dropped by 1.6% to 37.5p.WS