Offshore staff
LONDON -- Afren expects to achieve first oil next month from its Ebok field Phase I development offshore Nigeria, even though two of the major components have yet to reach the field location.
The floating storage and offloading vessel (FSO) remains in transit, having set sail from the Yulian shipyard in Shenzhen, China, on Dec. 2, and the mobile offshore production unit (MOPU) is currently in the Atlantic Ocean undergoing a dry tow.
However, the Phase I wellhead platform has been installed, as have all in-field flow lines and the 12 fixed-point mooring lines for the FSO.
Three of the five Phase I production wells were tested last month, delivering a total constrained flow of 12,500 b/d of oil. Afren anticipates output from these and the remaining producers of 15,000 b/d from Phase I, with first oil anticipated in February 2011.
Early this month, installation of the Phase II wellhead platform was completed at the West Fault block location. The jackupGSF High Island VII should start Phase II development drilling, comprising four horizontal producer and up to two water injector wells, early in February.
Afren anticipates production starting from Phase II at the beginning of March, with both phases of Ebok delivering a total of over 35,000 b/d by mid-year.
Nearby, Afren’s recently drilled Okwok-9 appraisal well has confirmed sufficient reserves for a commercial development of the Okwok field. The well was completed over a 35-ft 11-m) interval of D2 reservoir (average porosity 30%), flowing 31° API crude at rates constrained to ensure integrity of the completion.
After flowing for 48 hours, the well was shut in for a 54-hour build-up. The final build-up pressure was equal to the initial reservoir pressure, indicating no depletion. Well results support Afren’s subsurface model for the field, suggesting output under a development completion scenario of 2,000-4,000 b/d per well.
Development studies are under review, which include a tieback of Okwok as a satellite to Ebok field, or a standalone development, depending on the reserves base proves sufficiently large.
To assist this work, Afren intends to acquire new 3D seismic data over the broader Ebok/Okwok/OML 115 area during the first half of 2011, followed by further appraisal drilling during the second half of the year.
Elsewhere in the region, theGSF High Island VII has been drilling two infill producer wells at Afren’s Okoro field off southeast Nigeria.
The Okoro-11 and Okoro-12 infill wells are up-dip from the existing Okoro-4 and Okoro-5 producers in the lower sand in order to optimize sweep efficiency in that part of the field, and to access additional oil volumes. Afren expects these wells to add incremental volumes of 3,000-5,000 b/d of oil, lifting full year 2011 output from Okoro to an average of 16,000 b/d.
In the offshore Nigeria São Tomé & Príncipe Joint Development Zone block 1 (Afren 4%), Total has become operator. It has proposed drilling one appraisal well on the Obo discovery, which will also be tested, and one exploration well.
Finally, in the Keta block offshore Ghana, Afren (as operator) expects to drill one exploration well this year, but it is currently farming down a portion of its 70% interest ahead of this event.
Subsurface studies on the block have brought positive results, confirming prospectivity and identifying further potential in large-scale Turonian intervals analogous to those proven to be oil bearing at the Jubilee field and other discoveries in the area.
01/26/2011
