Journal de la pollution

Waha Reservoir Characterization and Distribution in the Ralah Field, Concession 6, Sirte Basin, Libya

Abstract

Fawzi SFH

The Ralah field is one of the concession 6 fields operated by sirte oil company. It is located in the southern part of the Sirte Basin (Libya), approximately 200 km south of the Mediterranean Sea. The upper cretaceous waha formation is the main producer in the Ralah Field. This reservoir is very complex and more heterogeneous. The Ralah Field was discovered in June 1964 with the drilling of DD1-6 well through the Waha formation and proved to be the most prolific reservoir in the area. The 2D seismic surveys were performed. In 2004 a 3D seismic survey of 340 km² was completed to evaluate remaining potential. The seismic interpretation has acquired new drillable well locations. From the history of the field, it is obvious that there have been successes and failures in the Waha reservoir in the Ralah Field. This can be attributed to facies variation, thickness and reservoir properties. Seismic and well data of nineteen wells have been used in this project. Waha reservoir was evaluated, analyzed and interpreted in order to gain a better understanding of the reservoir distribution over the study area. Seismic interpretation and coherence attribute analysis were performed for the fault trend identification; and using petrel software, Property models were constructed in terms of clay volume, porosity, permeability and hydrocarbon saturation. The aim of studying these properties is to decrease the risk and uncertainty of drilling infill wells in the field.