Porosity And Permeability Trend In Agbami-Field Using Well Log, Offshore, Niger Delta

Abstract

The need to provide comprehensive information on the reservoir characteristics of the offshore Agbami (ATA) oil field, Niger Delta, prompted the present study, which was designed to determine the porosity and permeability trends of three delineated formations across two wells and their relationships with compaction in the field. A well log suite consisting of gamma-ray, resistivity, neutron and density logs from two wells was used in the analysis. The well correlation study revealed stratigraphic continuity in the formations with varying degrees of thickness, which suggested the presence of faults. The results also indicated a shale volume range of 9% to 30%, which indicated a good fraction of clean sandstone in the formations. Over 20% formation porosity was observed indicating a very good ability to accommodate hydrocarbon fluids in the field. The study essentially determined reservoir properties such as lithology, depositional environments, shale volume, porosity (Φ), permeability (K), compaction trend and hydrocarbon fluid saturation, among others from well logs, which are variables that determine reservoir quality. The lithology of the wells was determined using a gamma-ray log. The high kick signatures of the gamma-ray delineate the shale intervals. Due to its highly conductive nature, shale lithology cause resistivity to shift to the far left. Porosity is generally high in all reservoirs, indicators for the volume of shale are low, water saturation is low, and permeability is high.