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अमूर्त

Carbonate Reservoirs Petrophysical Analysis of Bai Hassan Oil Field North of Iraq

Qays Mohammed Sadeq and Wan Ismail Wan Bin Wan yusoff

Bai Hassan Field is one of several elongated, asymmetrical, doubly plunging anticlines in northern Iraq. This field occupies a stratigraphically complex area comprising multiple facies developments of a complicated digenetic history. Abundant and variable porosity and permeability exist which, although primarily lithology dependent, are enormously enhanced by the development of intensive faults, fractures and joints, this combination ofuncommonly high porosity and permeability gives rise to enormously high and continuous production. The initial petrophysical interpretation consisted of a two-phase workflow. The first interpretation phase consisted of calculating both the dry mineral volumes such as calcite and dolomite and the total porosity using a matrix solution procedure. For a full suite of lithology and porosity, measurements (gamma ray, sonic, density, and neutron) up to four mineral components plus porosity were calculated. If fewer measurements were available, simpler lithology models were employed. Standard lithology models were set up for the observed assemblages of rock types. For example, models for the calcite-dolomite-anhydrite-porosity assemblage and the dolomite-calcite-clay-porosity assemblage were set up. When available, core data were used to check the interpretation model results and to adjust the model. The second interpretation phase calculated the water saturation using the Archie water saturation equation.