Reservoir Properties and Reservoir Model of the Mu Formation in the X Oil Field of Northern Iraq

Abstract

The Mu Formation is considered one of the most widespread Cretaceous periods in Iraq and its typical section is located in the province of Sulaimani in the Qamchuqa region. The study area is located in the X oil field, which is located to the southwest of the dome of Baba and southwest of the city of Kirkuk about 12 km and represents an asymmetrical subsurface fold whose axis extends in a Northwest-Southeast direction and the field is located in the unstable platform zone in the Foothill zone. The Formation consists of limestone and dolomitic limestone, organodetrital and argillaceous, the upper contact of the Formation is unconformable with the Dokan Formation, while the lower contact is graded with the Upper Sarmord Formation. The current study showed that most of the parts of the Formation contain a shale rate of less than 35%, and it was found through the logs (density, neutron and gamma rays) that the effective porosity rate is determined between (4-15) %, the rate of shale content is between (21-34) %  and the permeability rate is between (0.66-13.8) mD in a well XA, while in the XB well, the shale content rate ranges between (21-38)%, the effective porosity rate is between (8-18) %, and the permeability rate is between (1.6-18.8) mD. The Formation was divided into six reservoir units depending on the variation of shale content, porosity rate and permeability. The reservoir unit (MUE, MUC) is considered the best reservoir unit in the XA well, while the MUF unit has bad reservoir qualities in the same well. In the XB well, MUC & MUE are considered to be the best reservoir units, while MUF & MUB have less reservoir specifications compared to the previous two units. The water and hydrocarbon saturations were calculated with the movable and residual fractions of the invaded and uninvaded zones, as well as the total volume of water and oil within the Formation. After calculating the reservoir properties, the three-dimensional reservoir model was drawn by Petrel software to clarification the distribution of hydrocarbon saturation of the formation units; the net pay thickness of the Formation was calculated.