RESERVIOR CHARACTERISTICS OF KHASIB FORMATION IN AMARA FIELD, SOUTHERN IRAQ
The Khasib Formation of Late Cretaceous (Upper Turonian – Lower Coniacian) is considered important reservoir in the Amara oil field.
Knowledge of reservoirs rocks composition including fluid saturation and mineralogical components is essential for formation evaluations. The current study represents an evaluation study of the Khasib Formation using logs and cored data to evaluate the Khasib Formation in terms of its mineralogical, lithological composition and its petrophysical properties such as porosity and fluid saturation.
Logs data of 15 drilled wells in the Amara Field and cored intervals of the well Am11 from the Khasib Formation were conventionally processed and integrated. Also, the mineralogical components of the Khasib Formation were revealed using a simultaneous equation approach by computer processed interpretation (CPI), where, combination of 5 logs including gamma ray, sonic, density, neutron and resistivity was integrated.
The results show that the Khasib can be subdivided into upper and lower unit. It suggests that the Khasib Formation mainly consists of limestone with abundance of thin shale streaks concentrated at the upper parts. In addition, the lower part has an averaged porosity of about 0.185 (18.5%) and better hydrocarbon saturation, whereas, the upper part has recorded 0.121 (12.1%) averaged porosity. However, the lower part seems to be narrower than the upper part in terms of its thickness. The study furthermore, identified that the Khasib has deposited in a ramp setting during a transgression event caused by sea level change. Further study is needed to reveal the diagenesis process which affected reservoir quality of the Khasib Formation using petrographical techniques and to assess the Khasib Formation using the routine analysis techniques to detect directly porosity and permeability from plug samples.