PETROPHYSICAL EVALUATION OF SHALY SAND RESERVOIRS USING CMR TOOL IN OFFSHORE SEQUOIA FIELD, NILE DELTA, EGYPT

This work is devoted to the study of the petrophysical parameters (porosity-permeability- formation water resistivity-hydrocarbon and water saturation-shale content) for Sequoia Pliocene reservoir rocks in Sequoia field in west Nile Delta deep marine concession (WDDM). A suitable model was built for this reservoir using the conventional logging tools (Gamma ray-Density-Neutron-Resistivity) and the new logging tool (Combinable Magnetic Resonance tool “CMR”) in 4 development wells.
Comparisons between the different saturation models (Dual water and Indonesian) to select the best one applicable for this reservoir, plus comparison between CMR and conventional tools results were done.
A study of the lateral, vertical reservoir connectivity and mineralogical identification through pressure plots and Thorium, photo electric effect, and uranium cross plots was done.
The results show that average effective porosity calculated from Neutron-Density varies from 28% to 32%, while average effective porosity calculated from CMR using DMR method ranges from 21 % to 23%. The average water saturation calculated from conventional tools (Dual water and Indonesian) ranges from 38% to 68%, while the average water saturation calculated from CMR ranges from 39 % to 70%. The average calculated permeability from CMR using Timur-Coates model varies from 30 to 890 md. On the other hand, the results show that the water saturation from Dual Water model is the closest model to the water saturation calculated from CMR, and this variation is that conventional tools are fluid and lithology dependent, while CMR is only fluid dependent. The study recommended drilling new wells to develop this field