Application of Well Log Analysis to Assess the Petrophysical Parameters of the Lower Cretaceous Biyad Formation, East Shabowah Oilfields, Masila Basin, Yemen

Biyad Formation is mainly made up of clastic sediments that contain substantial amount of proven crude oil in the eastern Yemen. The Byiad clastic is divided into Upper and Lower Biyad clastic units. Several vertical wells have been drilled and penetrated this formation. This study is concerned with the petrophysical evaluation by means of well log data of the Lower Cretaceous rocks at the East Shabowah oilfields, Masila Basin, Yemen. Computer-assisted log analyses were used to evaluate the petrophysical parameters such as the shale volume (V ), total porosity (PHT), effective porosity (PHE), water saturation (Sw), hydrocarbon saturation sh (S ), flushed zone saturation (S ) and true resistivity (R ). Cross-plots of the Petrophysical parameters versus h xo t depth were illustrated. The Lower Cretaceous Biyad clastic reservoirs reflect that the matrix components are mainly sandstones, carbonates and shales. Moreover, the lithological-geologic model reflected that these shales are strongly affecting the porosity and consequently the fluid saturation in the Lower Biyad more than the Upper Biyad clastic units. On the basis of petrophysics data, the sediments of Biyad Formation are interpreted as a good quality reservoir rocks which has been confirmed with high effective porosity about 20 % and high hydrocarbon saturation exceeding 55%. The Biyad clastic units reveal promising reservoir characteristics especially Upper Biyad unit which should be taken into consideration during future development of the oilfields area.