Geological Modeling and Resource Estimation for Mishrif Formation in Nasiriyah Oilfield

Abstract

Resource estimation is an essential part of reservoir evaluation and development planning which highly affects the decision-making process. The available conventional logs for 30 wells in Nasiriyah oilfield were used in this study to model the petrophysical properties of the reservoir and produce a 3D static geological reservoir model that mimics petrophysical properties distribution to estimate the stock tank oil originally in place (STOOIP) for Mishrif reservoir by volumetric method. Computer processed porosity and water saturation and a structural 2D map were utilized to construct the model which was discretized by 537840 grid blocks. These properties were distributed in 3D Space using sequential Gaussian simulation and the variation in OWC depth was represented by 3 initialization regions for better characterization. The total STOOIP of Mishrif reservoir in Nasiriyah oilfield was estimated to be 8951 MMSTB which is divided between two reservoir units: MB1 and MB2 in which the first contains approximately 75% of total STOOIP and the latter has the remaining 25%.