The Tiof West exploration well was spudded on 8 December by the drillship "West Navigator" and has been drilled to a total depth of 2,991 meters. Since the last report (16 December) wireline logging operations were completed, including the collection of seven oil samples and one gas sample from the hydrocarbon bearing interval. The well was then plugged and abandoned on December 21, 2003, as planned.
As previously advised, evaluation of the wireline log and RCI pressure data indicates that the Tiof West well has intersected a total gross hydrocarbon column of 126 meters comprising an upper 4 meter gas interval overlying a 122 meter oil column above the confirmed oil water contact. The upper 4 meter gas interval is interpreted as an isolated gas sand within a larger gross oil column, as the oil column in Tiof West is structurally lower than the oil column in the Tiof-1 well. Of significance is the fact (reported by Woodside, December 16th) that the pressure data from the oil columns in both Tiof-1 and Tiof West are likely to be in direct communication, indicating a common oil pressure gradient across the larger Tiof Field.
Based on the common oil pressure gradient in both wells, a total gross oil column for the Tiof Field is estimated to be 214 meters, from the top of the oil column in Tiof-1 to the base of known oil in Tiof West. The Tiof Field has a relatively small gas cap as indicated by the 46 meter gross gas interval in the Tiof-1 well drilled near the structural crest.
The net to gross reservoir ratio (net sandstone distribution) for the Tiof Field is expected to be similar to that encountered in the Chinguetti Field. Reservoir quality in the Miocene sandstone systems varies depending on whether the well has intersected a channel centre or the more shale prone flanks of the channels. Further appraisal drilling will be required to assess the connectivity and the net to gross ratio of the reservoir section in the Tiof Field.
Hardman's technical staff have now undertaken preliminary mapping of the 3D and 2D seismic data over the Tiof-1 – Tiof West structure. The structural closure of the Tiof Field has a mapped area of approximately 54 square kilometers. On the basis of this area, the gross oil column indicated from both wells and the initial reservoir data, Hardman has estimated a potential field size of between 300 to 400 million barrels recoverable (statistical mean estimate).
Woodside is the operator of the Tiof West well.
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