International Science and Technology Journal

One key for meeting future energy requirements is to produce fields more efficiently. To achieve this, information must first be properly interpreted and studied in order to carry out reasonable estimates of hydrocarbons in place. A major application of petrophysics is in studying reservoirs for the hydrocarbon industry. Petrophysicists are employed to help reservoir engineers and geoscientists understand the rock properties of the reservoir, particularly how pores in the subsurface are interconnected, controlling the accumulation and migration of hydrocarbons. Some of the key properties are lithology, shale volume, porosity, saturation of fluid and net thickness .The study evaluate the reservoir quality of the upper Beda member limestone and dolomite by applying petrophysical analysis method for five selected wells in Balat oil Field in concession 59 (vv6, vv7, vv11, vv12 and vv18 analyzed by Techlog software. The results show generally good reservoir quality with net pay thickness ranging from (61 to 153) feet, where shale volume obtained that varies with zones is between 8 and 22 % volume fraction. The upper Bead member has very good Porosity reached up to 25%, as the carbonate porosity increasing by digenesis process. Average water saturation obtained is between 35 and 56 %.The oil water contact (O.W.C) is placed at depth =-4485 Sub Sea.