Afren, Partners Optimum and Lekoil struck gold mine offshore NigeriaStaff writer ▼ | November 21, 2013
OPL 310 is located in the Upper Cretaceous fairway that runs along the West African Transform Margin. Extending from the shallow water continental shelf to deep water, the block represented a wild cat exploration opportunity in an under-explored basin.
Detailed pre-drill evaluation of the block identified several prospects lying in the same Turonian, Cenomanian and Albian sandstone intervals that have yielded significant discoveries in Ghana and Côte d'Ivoire.
The first exploration well drilled by the Partners was the Ogo prospect, a four-way dip-closed structure in the Turonian to Albian sandstone reservoirs, which was targeting 78 million barrels of oil equivalent (mmboe) of gross P50 prospective resources.
The drilling programme included a planned side-track, testing a new play of stratigraphically trapped sediments that pinch-out onto the basement high targeting 124 mmboe of gross P50 prospective resources. In total, the Partners were targeting 202 mmboe of gross P50 prospective resources.
The Ogo-1 well was drilled to a total measured depth of 10,518 ft, and encountered a gross hydrocarbon section of 524 ft, with 216 ft of net stacked pay. The Ogo-1ST reached a total measured depth (TD) of 17,987 ft and encountered hydrocarbon intervals in the same Turonian, Cenomanian and Albian reservoirs that were successfully drilled and logged at the Ogo-1 well. In addition, the syn-rift section encountered a 280 ft true vertical thickness gross hydrocarbon interval.
Based on the well data, the Partners estimate the P50 to P10 gross recoverable resources range to be significantly ahead of pre-drill expectations at 774 to 1,180 mmboe across the Ogo four-way dipped closed and syn-rift structures. Additional upside potential is expected in the syn-rift play.
In addition, the latest PVT (Pressure-Volume-Temperature) analysis confirms excellent reservoir fluid properties. The partners expect the syn-rift to contain a light oil or a condensate rich gas. ■