Evaluation of Petrophysical Characteristics of Carbonate Mishrif Reservoir in Ahdeb oil Field, Central Iraq

Abstract

Ahdeb oil field is located in the central block of Mesopotamia plain in Iraq. It has three domes AD-1,   AD-2, and AD-4.The current study represents characterization of carbonate Mishrif reservoir (Cenomanian-Early Turonian) in three wells (AD-A,AD-B,AD-C) at southern dome of Ahdeb oil field. Petrophysical properties were calculated using available well logs data such as neutron, density, sonic, gamma ray, resistivity and self-potential logs. These logs are digitized and then environmental corrections and interpretations were carried out using Techlog software. Petrophysical parameters such as shale volume, porosity, water saturation, hydrocarbon saturation, bulk water volume, etc. were determined and interpreted and illustrated in computer processing interpretation (CPI).Mishrif Formation was divided into five units according to reservoir properties (MI-1,MI-2,MI-3,MI-4 and MI-5). These units differ from each other’s by reservoir properties. The unit MI-4 is the best reservoir unit in Mishrif Formation that has good petrophysical properties such as high porosity and low water saturation. The MI-4 unit represents the principle oil bearing unit in Mishrif Formation.The other units of Mishrif Formation are characterized by high water saturation with variations of effective porosity that indicated of these units are free oil shows.