LONDON – Tower Resources has issued an update on its work on the Thali license offshore Cameroon, conducted via its subsidiary Tower Resources Cameroon.
The latter has a 100% interest in the shallow water Thali (ex-Dissoni) production-sharing contract (PSC) in the offshore Rio del Rey basin, awarded on Sept. 15, 2015 for an initial three-year exploration period.
The concession covers 119.2 sq km (46 sq mi) in water depths ranging from 8-48 m (26-157 ft) in Rio del Rey, a sub-basin of the Niger Delta which has to date produced more than 1 Bbbl of oil with estimated remaining reserves of 1.2 Bboe, primarily at subsurface depths of less than 2,000 m (6,562 ft).
Tower believes the Thali block could hold up to four distinct oil play systems, including the established play in which three discovery wells, one gas (Rumpi-1), one oil and gas (Njonji-2) and one oil (Njonji-1), have already been drilled.
Prior to interpretation of recently reprocessed 3D seismic data over the block, the most recent oil-in-place estimate for the Njonji discovery was 39 MMbbl, with 7-15 MMbbl recoverable.
Tower has now completed its environmental and social impact assessment covering its planned drilling on the block, including a well that the company is currently preparing to drill on Njonji.
The company submitted its report to the government in late June and received its certificate of environmental compliance on Aug. 6. This is valid for drilling operations encompassing multiple wells in the Thali license area, subject to operations starting over the next three years.
In addition, Tower has filed for an extension of up to one year of the license’s initial exploration period with the Ministry of Mines, Industry and Technological Development – the present expiration date is Sept. 14, 2018.
Finally, the company has undertaken substantial G&G work since receiving the reprocessed 3D seismic in April, which it has shared with Oilfield International Ltd., the consultants that are compiling the reserves report.
Initial interpretation of the reprocessed data suggests the gross intervals of key reservoirs increase toward the south and/or west of the original NJOM-1 well drilled by Total.
In addition, the improved resolution has provided a clearer definition of the faults that potentially separate the fault block compartments in Njonji but has also raised questions over whether some of these are actually sealing or not.
This suggests there might be fewer, larger fault block compartments at Njonji than the five originally interpreted by Total and later Tower itself.
The company is therefore undertaking further petrophysical analysis of nearby wells, using sonic/density/deep induction logs to enhance the seismic in order to better match the well log spectrum. This process emphasizes the higher frequencies and should lead to improved resolution.
And Tower is also refining its depositional model with more focused and detailed thickness mapping, to aid evaluation of the reservoir interval changes in 3D. Dr Tim Needham of The University of Leeds Institute of Applied Geoscience will conduct a fault seal analysis.
At the same time Tower is negotiating rig and associated service contracts for the upcoming Njonji well, having selected a provisional well location and performed well engineering.