26 November 2013, Lagos – United Kingdom-listed Afren Plc and its partners – Optimum Petroleum Development Limited and Lekoil Limited have suspended the current drilling operations at the Ogo prospect located on the oil prospecting lease (OPL) 310 licence offshore Nigeria after the drilling results surpassed expectations significantly.
In geological parlance, 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.
Afren said in a statement that a 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. The drilling programme included a planned side-track, testing a new play of stratigraphically trapped sediments that pinch-out onto the basement high,” said the statement.
The statement added that the Ogo-1 well was drilled to a total measured depth of 10,518 feet (10,402 feet true vertical depth subsea).
According to Afren, the Ogo-1ST reached a total measured depth (TD) of 17,987 ft (12,050 ft true vertical depth) and encountered hydrocarbon intervals in the same Turonian, Cenomanian and Albian reservoirs that were successfully drilled and logged at the Ogo-1 well.
The Chairman of Afren, Mr. Egbert Imomoh, said: “The Ogo and Ogo-1ST discovery continues a 100per cent exploration track record following discoveries at Ebok North Fault Block and the Okoro East Extension in Nigeria and the Simrit-2 and Simrit-3 exploration wells in the Kurdistan region of Iraq. Based on the well data, the Partners have identified volumes in excess of our pre-drill estimates. We look forward to further exploration results in East Africa on the El Kuran well and in Kurdistan on Maqlub-1 and the exploration tail on the BR-5”.
Based on the well data, the Partners estimate the P50 to P10 gross recoverable resources range to be significantly ahead of pre-drill expectations across the Ogo four-way dipped closed and syn-rift structures.
Additional upside potential is expected in the syn-rift play. The partners expect the syn-rift to contain a light oil or a condensate rich gas.
While circulating bottoms up at TD, the drill string parted at 3,390 ft and during good progress towards recovery of the drill string from the well bore, the well took a hydrocarbon kick. After the kick was safely controlled, the partners considered it prudent to move to permanently secure the well. The Partners intend to drill an appraisal well in H2 2014, ahead of development planning and will also increase 3D coverage on the block, currently covering only 25 per cent of the block, to define further prospectivity.
Afren has 22.86per cent participating interest and 40 per cent economic interest in the block, while Optimum has 60 per cent and 30 per cent participating interest and economic interest, respectively.
– This Day