LONDON -- Xcite Energy has drilled the 9/3b-5 Bentley field appraisal well to a total depth of 4,105 ft (1,251 m) and encountered heavy oil bearing Palaeocene Upper Dornoch Formation sands at 3,712 ft (1,131 m) with 87 ft (27 m) gross hydrocarbon column.
During the drill stem test, 100% crude oil production was demonstrated at rates of up to 150 b/d from the 50 ft (15 m) section of the oil column that had been successfully perforated. This flow rate was within the expected range for a test of this design and nature.
Data Review and Interpretation
Schlumberger has reviewed and interpreted the data obtained from the well, together with the hydrocarbon and fluid samples recovered from the drill stem test. Based on this review and interpretation, Schlumberger has confirmed:
1. Analysis of the pressure build up indicates a high permeability formation of greater than five Darcies, with a reservoir pressure of 1,630 psi at 3,730 ft (1,137 m) MDRT.
2. The well, as anticipated, demonstrated a high "skin" of 29, consistent with an appraisal well with drilling damage, limited entry perforations and a thick cemented zone due to borehole washout during drilling. This high skin value significantly impaired the productivity of this vertical appraisal well.
3. Adjusting the "skin" to five for production well conditions, assuming the use of a gravel-packed 3,000 ft (914 m) horizontal well 15 ft (5 m) from the top of the formation and using a kv/kh ratio of 1, the forecast flow rate from such a well in the reservoir would be circa 4,400 b/d of oil with zero water cut. This low skin value, which is achievable for a production well using current technologies, demonstrates the expected productivity in reservoir conditions.
Based on these well test results and the Schlumberger data review and interpretation work, the company believes that commercially viable production rates are achievable through the application of horizontal well technology coupled with appropriate artificial lift techniques, including submersible pumps. Xcite is now planning for the next phase of the development process for the Bentley field, which will use EOR techniques consistent with the qualities of the reservoir and characteristics of the crude oil.
Following the success of the 9/3b-5 appraisal well, the company is re-processing the 3D seismic data over the block to confirm the results of its recent 3D interpretation, which indicated a material increase in STOIIP compared to the 2D seismic.