SPE 127599 3D Geological Modeling of a Tight Naturally Fractured Carbonate Reservoir as an Input to Reservoir Simulation - A Case Study from North Kuwait Jurassic Fields

摘要

Dedicated exploration efforts targeted on the Jurassic reservoirs in North Kuwait culminated in the discovery of six separate fields, encompassing an area of approximately 1,772 km~2. These reservoirs are known to hold commercial accumulation of gas, gas condensate and volatile oil and are currently in an early phase of development. The producing Jurassic reservoirs belong to the Marrat, Sargelu and Najmah Formations of Toarcian to Tithonian ages. These reservoirs consist of tight carbonates with several other complex lithologies and are naturally fractured with fractures acting as a driver to production in the Najmah and Sargelu formations and fractures acting as production assist in the Marrat Formation. A 3D geological model was developed for these reservoirs. The static geological model consists of a matrix model capturing the facies, and other matrix reservoir properties like porosity, permeability and water saturation; and the fracture model captures the fracture properties like fracture porosity, permeability and matrix to fracture coupling parameters. The model framework was guided by seismic horizon interpretation from 3D seismic data while the model vertical resolution was optimized to adequately capture the log defined reservoir properties. Electro facies were interpreted at wells with extensive core calibration and were used to develop a 3D facies model capturing the worked out depositional environment. This facies model was used to develop the porosity, permeability and water saturation models using the processed wireline log data, core plug based measurements. The 3D fracture model was developed capturing the areal distribution of fractures using the calibrated 3D seismic volume curvature attribute as soft data and constrained vertically by hard data from image log and cores from wells, thus bringing robustness and reliability for planning the development wells. This 3D geological model was optimally upscaled depending on the aerial well density for use of flow simulation studies.