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Research Paper | Geology | Niger | Volume 11 Issue 12, December 2022
Effect of Oil in Place on Sandstone Reservoir Quality of Dibeilla Prospect, Termit Basin, Niger: Insight from Pre-Stack Seismic Inversion and Diagenesis
Hamma Ada Moussa | Abdou Dodo Bohari | Hassan Ibrahim Maharou [2] | Abdourahamane Ibrahim Ari Maina | Moussa Harouna
Abstract: Paleogene Sokor1 Formation, an important exploration target in the Termit Basin, is a typical sandstone hydrocarbon reservoir. This paper used core samples, wireline logs, and seismic data collected in the Dibeilla prospect to determine the impact of oil occurrency on reservoir quality. Cores were analyzed based on thin sections, scanning electron microscopy, X-ray diffraction, and a range of pre-stack inversion modeling approaches by integrating wireline logs to seismic data. Distributions of all potential influencing factors on porosity and permeability were quantified, assessing the influence of all potential controls on the quartz cement. Precise oil saturation of each sand group has been determined using the outputs pre-stack inversion. The main authigenic minerals are quartz overgrowth and clay minerals, which occur as pore-filling and pore-lining cements, reducing porosity and permeability. Quartz overgrowth occurs with varying frequency on both sides of the study area throughout the diagenetic history. The high occurrence of quartz overgrowth in the northern part containing mainly water reservoirs, and the low occurrence in the southern part containing mainly oil reservoirs, indicates that quartz cementation was inhibited by oil emplacement in these facies and is with significant control on porosity and permeability preservation. Reservoir quality in the Dibeilla prospect is primarily determined by a combination of microcrystalline quartz controlled by depositional facies with dissolved secondary porosity and early oil emplacement. Results demonstrate the robust application of combining diagenesis and seismic inversion in predicting favorable reservoirs, useful in reducing exploration risk in undrilled areas and oilfields with similar geologic settings.
Keywords: Reservoir simulation, sandstone diagenesis, quartz cement, oil effects, reservoir quality, Dibeilla prospect, Niger
Edition: Volume 11 Issue 12, December 2022,
Pages: 1203 - 1226