Bowleven: Further Drilling Success with Sapele-1 Discovery Well Off Cameroon

Bowleven, the West Africa focused oil and gas exploration group traded on AIM, announces that the Sapele-1 exploration well drilling in the Douala Basin, offshore Cameroon has encountered further hydrocarbon-bearing pay in both the Tertiary and Cretaceous objectives based on the results of drilling, wireline logs, samples of reservoir fluid and pressure data.

The well was designed to intersect multiple stacked objectives of Tertiary to Cretaceous age. Wireline log evaluation indicates all of the five objectives to be hydrocarbon-bearing with net pay confirmed in three, based on fluid samples. The well has reached a current total depth (TD) of 4,539 metres and the intention is to set liner and drill onwards, subject to attaining various approvals, on completion of current logging activities.


  • All five target objectives indicated to be hydrocarbon-bearing from log evaluation; net pay confirmed in three post sampling.
  • Increased oil in-place estimates for Deep Omicron; P90 to P10 now 65 to 430 mmbbls.
  • Cross-cut objective encountered 4 metres of log evaluated net hydrocarbon pay.
  • Gas condensate encountered in Epsilon Complex validates Cretaceous prospectivity; extends play fairway significantly offshore.
  • Further Cretaceous reservoir potential identified; Sapele-1 drilling planned to continue on completion of current logging activities.
  • Epsilon Complex volumetrics to be updated following integration and evaluation of extensive well data.
  • Preparing for testing and subsequent appraisal drilling/sidetrack activity.
  • Group cash at 31 December 2010 circa $190 million; well positioned to fund forward work programme.


Drilling update

The Sapele-1 exploration well location, on block MLHP-5 in the Etinde Permit, was selected to intersect multiple independent exploration targets from the proven Miocene fairway down to the deeper Cretaceous fairway from a single location. This required that a number of the targets be intersected at sub-optimal locations. Consequently, while the well has confirmed the prognosed targets as hydrocarbon-bearing, this is believed to have occurred at the extremities of Lower and Deep Omicron and the Cretaceous Epsilon Complex.

Since the announcement on 25 November 2010, the well, which is drilling in shallow water depths of around 20 metres, has been drilled to a current TD of 4,539 metres and has drilled through the Cross-cut event and into the Cretaceous.

A principal objective of the Sapele-1 well was to prove the concept of the Cretaceous play offshore Douala Basin. The well has now confirmed the presence of reservoir and hydrocarbons in the Cretaceous, offshore Douala Basin, and as a result extends the Cretaceous play fairway significantly offshore.

The updates for these most recent reservoir sections are outlined below:

Cross-cut event

The well has intersected a log evaluated gross hydrocarbon interval of approximately 18 metres in what are believed to be moderate quality interbedded reservoir sands. The provisional net pay is estimated to be approximately 4 metres, with an average porosity of 17%.

Epsilon Complex

The well has intersected a log evaluated gross hydrocarbon interval of approximately 9 metres in moderate to good quality reservoir sands. The Cretaceous net pay encountered to date is estimated to be approximately 4 metres, with an average porosity of 13%. Fluid samples acquired during logging activities confirm the presence of lean gas condensate as reservoir fluid.

It is believed that the well has encountered additional sands at the current TD. Further Cretaceous targets have also been identified and consequently, drilling is planned to continue upon completion of current logging activities.

Initial in place estimates

Following the identification of additional net pay at Deep Omicron Bowleven’s (as operator) in-place volumetrics on a P90 to P10 range have been revised upwards to 65 to 430 mmbbls (updated mean 217 mmbbls). These numbers are subject to ongoing revision following

further evaluation and additional appraisal drilling. Due to the stratigraphic nature of the Omicron discoveries, further appraisal will be required and is being planned.

Updated volumetrics for the Epsilon Complex will be generated following completion of the well and the integration and evaluation of the extensive well data acquired.

Sapele-1 forward programme

Wireline logging operations are ongoing over the Cross-cut and Epsilon Complex intervals. Once completed, it is planned to continue drilling, subject to required approvals and agreement with the joint venture partner, further into the Cretaceous. The forward plan will be reviewed by the joint venture on reaching the revised target depth and on completion of logging activities.

Meanwhile, preparations for testing Sapele-1 are underway and any testing will be undertaken once drilling and logging activities are completed. Due to the stratigraphic nature of these discoveries further evaluation and appraisal will be required to determine commerciality. Consequently, planning for sidetrack/appraisal activities is in progress and this activity is expected to commence on completion of the testing programme.

Further update announcements on drilling activities will be made as appropriate.

Financial position

The Group has circa $190 million cash and no debt at the 31 December 2010. This excludes approximately $35 million proceeds anticipated from the disposal of EOV. Consequently, the Group is well funded to carry out the extensive work programme envisaged for 2011 across its acreage.

Kevin Hart, Chief Executive of Bowleven plc, commented:

“2010 has been an exciting year for Bowleven. As we enter 2011 the ground-breaking Sapele-1 exploration well continues to excite and highlights the potential of the Douala Basin. Whilst further evaluation and appraisal are required, the Sapele-1 well has the potential to be transformational. The discovery of oil at Sapele-1 in high quality Miocene reservoirs and in shallow water depths is significant in terms of both acreage-wide prospectivity and potential future development. The Cretaceous result also validates the play within this part of the Douala basin and has potentially significant implications for the overall prospectivity of the Etinde Permit. Furthermore, the Sapele-1 well will have a pivotal role in calibrating and de-risking the multiple exploration prospects identified across Etinde. The momentum is continuing to build in our operations in Cameroon and 2011 promises to be our busiest year yet with an extensive exploration and appraisal programme planned.”


Source:Bowleven, January  10, 2011;