Petrographic Analysis and Diagenetic History of Reservoirs in the Sokoto Basin, Kebbi State, North West Nigeria

The Sokoto Basin of North West Nigeria contains sedimentary sequences with reservoir potential that has not been fully evaluated, partly due to the limited availability of detailed petrographic and diagenetic studies that could characterise reservoir quality for prospective hydrocarbon exploration targets. This study presents a petrographic analysis and diagenetic history of sandstone samples from Cretaceous and Paleocene outcrop analogues and cored intervals from two boreholes drilled within the Sokoto Basin, Kebbi State. Forty-eight thin sections prepared from core and outcrop samples were analysed using transmitted light and cathodoluminescence petrography. Point counting was performed to quantify framework grain composition, cement types, and secondary porosity. Diagenetic events were sequenced relative to compaction, cementation, and dissolution phases to reconstruct the paragenetic sequence. Results indicate that initial high porosity in clean quartz arenites (mean primary porosity 30 percent) was reduced to current values averaging 12 to 18 percent by a combination of mechanical compaction, quartz overgrowth cementation, and kaolinite pore-filling. Leaching of feldspar grains and carbonate cements has generated secondary porosity that partially compensates for cementation losses. The study concludes that reservoir quality is moderate but heterogeneous and recommends stimulation by acid treatment as an essential component of any future well completion strategy in the Sokoto Basin. Keywords: petrography, diagenesis, reservoir quality, Sokoto Basin, Kebbi State.