Prediction of Sand Body Trend Based on Stratigraphic Dip Pattern from Microresistivity Images in Permian Sandstone Reservoir, Oman

Abstract

Abstract Stratigraphic dip patterns from high-resolution microresistivity images can indicate the paleocurrent direction of sediments transported by water and the associated depositional environment such as sand-filled stream channel and flood plain. This information was successfully used in the prediction of sand body orientation trends of an oil field in Oman. The interpretation and analysis of the stratigraphic dip patterns from the images complemented conventional seismic data and well logs in the sand body characterization. The sand body orientation trends were predicted from the oriented stratigraphic dip patterns of the sedimentary sandstone beddings observed on the images and the depositional energy analysis through the dip magnitudes of the beddings on the images, and the associated depositional environments were reconstructed using the sedimentary structures and textures on the images. The prediction and analysis of the sand body orientation trend finally provided the classification of the sand bodies that correspond to the different reservoir parameters for further field development. The main contributor to hydrocarbon reserves and production in the field of North Oman is the sandstone reservoir of the Permian formation, which was dominantly formed in the fluvial and floodplain depositional environment. The uncertain sediment supply direction and complicated faults or sedimentologically confined compartments make reservoir characterization and modeling in the oil field very difficult, if not impossible, with only the traditional seismic data and well logs. In fact, the current field development demonstrates that in the oil field, the Permian sandstone reservoir contains structural traps and stratigraphic traps. Detailed sand body orientation trend is very important in further field development, but almost impossible using only conventional well logs and seismic data. For the prediction of sand body trend in the case studies, firstly, the interpretation of the stratigraphic dip patterns was performed on each of the 30 wells, and secondly, the correlation of oriented sand bodies was analyzed within the multiwell scale of the field. Finally, from the multiwell correlation of oriented sand bodies, the sand body orientation trend was established. An improved understanding of sand body characterization and modeling in the field was obtained to reduce the risk of drilling unsuccessful wells.