Evaluation of Shale Effect on Saturation Exponent from Well Logs in an Offshore Field, Niger Delta.

Hydrocarbon recovery is subject to various elements set to validate not only the availability of the type of fluid present at the subsurface, but also how saturated is the host rock with the fluid. A study on saturation was carried out on the hydrocarbon locked in reservoirs of the N-1 and D-1 wells. The water saturations were determined using various saturation equations by various authors from literatures. This evaluation led to the determination of the permeability of the reservoirs through the Timur equation and the values were within the range 222.8mD-2518.5mD in well N-1 and 434.4mD-2534.3mD in well D-1. The 7 pay zones of both wells showed a high correlation based on the petrophysical parameters which could be the basis of a conclusion of lateral continuity across the reservoir although the formations interpreted are characterized by clay fingering. An analysis carried out for the determination of the permissible range of the saturation exponent ‘n’ used and assumed as 2 which agrees with that in the basic Archie equation, but for the BOD-1b zone of D-1 with both values 1 and 2 perfectly matching