LONDON -- Tullow Oil’s latest exploration well in the Deepwater Tano license offshore Ghana has encountered water-bearing reservoirs.
Onyina-1 was targeting a large, Campanian prospect between the Tweneboa and Jubilee fields in the northeast of the license. It intersected 49 m (161 m) of good quality sandstone reservoir, but these turned out to be water bearing at this location.
TheSedco-702 semisubmersible drilled the well to a TD of 2,730 m (8,956 ft) in a water depth of 828 m (2,716 ft). It will next transfer to the Jubilee Unit to assist with preparations for first oil from the Jubilee field later in 2010.
Angus McCoss, Tullow’s Exploration Director, said: “The negative test of the Campanian reservoirs in the Onyina prospect enables further refinement of our exploration and relinquishment strategy offshore Ghana. Good quality Campanian reservoir sands were found as predicted, however the lack of hydrocarbons at this location highlights the high risks of charging and trapping oil in this secondary play.“Our main focus remains on the lower risk primary play, the deeper more prospective Turonian reservoirs, where we have had such outstanding success with Jubilee, Tweneboa and Owo.”