Depositional and Diagenetic controls on Reservoir Characteristics of X-well and K-well, Ogban Field, Niger Delta

Abstract

Sedimentological subsurface study of X-well and K-well reservoir sand bodies located in the Niger Delta was carried out to determine the influence of depositional environment and diagenetic control on the reservoir characteristics. Lithofacies analysis reveals the presence of sandstones, siltstones, mudstones and heterolithics. Based on the detailed sedimentological description, wire line logs evaluation and trace fossils analysis, the X-well and K-well reservoirs are interpreted as a barrier complex deposit of fluvio-deltaic—shallow marine environment. Petrographic studies reveal quartz as the dominant mineral with minor amount of feldspars. Cements include silica, quartz overgrowth and siderite. Facies analyses indicate porosity loss due to compaction, and variations in the diagenetic pathway observed in the different facies are closely related to primary mineralogy as influenced by palaeodepositional environments.