Oil resources discovered so far onshore Kenya are expected to be well in excess of 300 MMBO, “exceeding the threshold for development studies to commence”, according to Tullow Oil, the leading operator in the East African country. The company arrived at the figures, “following success at Etuko-1”, which was spud in May 2013 and is still drilling.
Although Tullow has successfully tested two discovery wells, the 300MM figure is considered contingent and not reserves estimates. “Firstly, Pmean is not typically descriptive of reserves. Tullow must have technical or commercial constraints preventing the classification as reserves, he argues. “For it to be classified as reserves you must have a development plan, it must be commercial and it must have clearly defined means of producing the hydrocarbon”.
Tullow itself says the resources discovered to date are of a scale that the partnership will initiate discussions with the Government of Kenya and other relevant stakeholders to consider development options. These discussions include consideration of a ”start-up phase” oil production system with potential to deliver significant production rates with oil export via road or rail in advance of a full-scale pipeline development. To facilitate these development activities in parallel with exploration and appraisal, an “Area of Interest” (AOI), encompassing the basin discoveries and further prospects in Blocks 13T and 10BB, was agreed with the Government of Kenya in February 2013. This agreement allows a multiple field approach to development of the resources while permitting the continued focus on exploration to increase the resource base while concurrently appraising discoveries.
Tullow’s flow tests of the two initial discoveries: Twiga South-1 and Ngamia-1, were completed in February and July 2013 respectively. Both wells flowed at a cumulative constrained rate of around 3,000 BOPD of 25 to 35 degree API sweet waxy oil with no indication of pressure depletion. “These tests resulted in the doubling of our previous estimates of net oil pay, proved the potential to achieve an unconstrained rate of over 5,000 BOPD per well and significantly increased discovered volumes to over 250 MMBO”, the company says in its half year 2013 report. “Ekales-1, the next exploration well in the Basin Bounding Fault Play, on trend with Ngamia and Twiga-South, commenced drilling on 22 July 2013.
Tullow plans to shoot a 550 sq km 3D survey over the area, to “support our appraisal programme”. It is scheduled to commence in the third quarter of 2013. Etuko-1, located 14 km east of Twiga South-1 in Block 10BB, is the first test of the Basin Flank Play in the eastern part of the basin. “In the results of drilling in this well, wireline logs and samples of reservoir fluid confirm a new oil discovery with net pay of over 40 metres in the Auwerwer and Upper Lokhone targets. Etuko-1 was then deepened into the Lower Lokhone sands and encountered an additional 50 metres of potential net oil pay which will be included in a programme of flow testing later in 2013, to determine their production potential. Although the Lower Lokhone sands have been established to be poorer quality than the main objectives in the Auwerwer and Upper Lokhone, we have successfully flowed oil from this interval at Ngamia. Once operations at Etuko-1 are complete, the rig will move to the Agete prospect north of Twiga-South “.