Petrographic Analysis of Sandstone Reservoirs in the Niger Delta Basin, Bayelsa State

Sandstone reservoirs within the Niger Delta Basin represent some of Nigeria's most economically significant hydrocarbon accumulations, yet their petrographic character varies considerably across sub-basins. This study undertakes a detailed petrographic analysis of sandstone core samples obtained from selected wells in Bayelsa State, South South Nigeria, with the objective of characterising porosity, mineralogical composition, and diagenetic history. Thin sections were prepared from core plugs and examined using polarised light microscopy to identify framework grains, cement types, and pore geometry. Point-count analysis was conducted on each section to determine the relative abundance of quartz, feldspar, lithic fragments, and authigenic minerals. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy was applied to selected samples to resolve clay mineral assemblages and micro-porosity. Results are evaluated against the Folk classification scheme to assign reservoir quality categories. Understanding of compaction trends and cementation phases is critical because these processes govern permeability pathways and hydrocarbon migration efficiency. This study further correlates petrographic observations with available wireline log data to validate microscopic interpretations at the formation scale. Findings are anticipated to assist in predicting reservoir quality in analogous undrilled structures, thereby supporting field development planning by operators in the South South geopolitical zone. The research provides foundational petrographic data relevant to ongoing exploration activities in the Niger Delta. Keywords: petrography, sandstone reservoir, Niger Delta, diagenesis, porosity.