The company said multiple objectives have been interpreted in this prospect. Based on seismic correlations between Waraga-1 and Mputa-1, the company said it expects to intersect deeper objectives, similar to the oil-bearing intervals in Mputa-1, before Waraga-1 reaches total depth.

Analysis of wireline logs, which were run to a depth of 1768m, indicates the well has encountered a gross oil interval of 32m with a net pay ratio of about 50%. But samples are yet to be recovered from the well due to problems with the wireline sampling tool, Hardman said.

The company said no oil-water contact had been observed so far, although the well had now passed into probable water-bearing sands below the hydrocarbon interval.

On Monday night, the well was drilling ahead at 1872m towards a revised planned total depth of about 2050m. Hardman said wireline logs, including a pressure and sampling program, would be conducted to further evaluate the reported hydrocarbon interval and the expected deeper objectives.

Waraga-1 is 19km northeast of the recently drilled Mputa-1 oil discovery well and 41km southwest of the 1938 Butiaba Waki-1 well.

Waraga-1 is testing a structural prospect with identical geological targets to the oil-bearing reservoirs seen at Mputa-1. The geological risk at the Waraga prospect, which was defined by the 2005 onshore seismic survey, was significantly reduced by the success of Mputa-1, the company said.

Hardman chief executive and managing director Simon Potter said the initial results, in addition to the drilling of deeper targets and planned additional testing of hydrocarbons at Waraga-1, made it a strong follow-up well to Mputa-1.

“Combined, these results give us considerable confidence for realising additional potential in the region, which will give strong impetus to an appraisal and commercialisation process,” he said.

Hardman and Tullow Oil each hold a 50% interest in Block 2 and the Waraga-1 well.