Depositional and Diagenetic Controllers on the Sandstone Reservoir Quality of the Late Cretaceous Sediments, Gulf of Suez Basin

Abstract

The complex of depositional, burial, and diagenetic histories of the Late Cretaceous Nezzazat Group sandstones in Northeastern Africa present the main challenges with regard to reservoir quality. The quality of commercial reservoirs is maintained despite deep burial and the associated high temperature and pressure. The study presents optimum integration of different dataset to address the reservoir quality and reservoir performance controllers. The dataset includes measured porosity and permeability, petrographic point counting data, grain size analysis, X-ray diffraction data, scanning electron microscopy and compaction porosity loss by. The depositional controls on the reservoir quality are the facies, where the higher quality found in the channel and the upper shoreface settings. The coarse-grained sandstone associated with better reservoir quality. The large intergranular porosity is the main porosity control to the fluid to flow. The massive and laminated sandstones are the best quality facies. The labile grains (feldspars and mica) control the permeability distribution. While the secondary diagenetic controllers are the carbonate cementation that inhibited the effects of compaction. The siderite cementation has resulted in a micropore dominated and highly tortuous pore system. Total porosity has largely been preserved in the siderite-cemented sample but virtually eliminated in the dolomite cemented. Low volume of illite associated with better reservoir quality. While the better reservoir quality associated with abundant quartz cementation that protected the primary porosity from compaction. Compaction act as a significant porosity loss factor during diagenesis. Authigenic kaolinite does not significantly affect the reservoir quality. The reservoir sensitivity to formation damage come from the potential for fines (kaolinite, illitic clays, siderite and pyrite) migration within the pore system that are readily to mobilize by fluid flow.