Integrated Reservoir Characterization for Thin Waterflooded Carbonate Oilfield in Oman

摘要

Reservoir characterization is the most important in building robust geological and simulation models. The improvement in reservoir characterization enhances the understanding of the reservoir heterogeneity and reduces the uncertainties on field development. This can be achieved with better descriptions of reservoir frameworks and properties. D oilfield is located in northwest of Oman and it has been rejuvenated by water injection since 2001 using horizontal well line driving pattern. In this paper, comprehensive reservoir characterizations of thin Early Cretaceous Upper Shuaiba limestone reservoir of this oilfield were carried out based on the current data for guiding the further adjustment plan and achieving better development results. Horizontal well correlation modes were defined based on the reservoir boundary encountered by the horizontal trajectory to construct the reservoir framework. The interpretation and identification of small faults and fractures were identified based on seismic data, FMI logging, core data and production data. Under the guidance of depositional model, data from horizontal wells has been fully used in combination of pseudo-wells to build the 3D geological model to accurately delineate small faults, reservoir boundaries and property distributions. Based on fracture parameters derived from static and dynamic data, fracture network model and equivalent permeability model have been built constrained by fracture density. The intelligent reservoir characterization provides a reliable geological guidance to ensure the reasonable placements of infill horizontal well trajectories through the reservoir. The real horizontal drilling indicates that the oil reservoir accounts for 90% of the total horizontal section for D oilfield.