Petrophysical and reservoir characterisation of MAR field onshore of Niger Delta, Nigeria

Abstract

The Niger Delta Basin is a prolific hydrocarbon province with complex depositional environments influenced by alternating transgressive and regressive phases. This work focuses on the MAR Field, onshore Niger Delta, analysing reservoirs M1, M2, and M7 to evaluate the petrophysical properties and depositional environments critical for hydrocarbon exploration. We used gamma ray, resistivity, neutron, and density logs from four wells to assess key parameters such as porosity, permeability, water saturation, and hydrocarbon saturation. The analysis indicated favourable petrophysical properties across the reservoirs, with net-to-gross ratios greater than 60%. Reservoir M1 presented excellent porosity (23.8%) and permeability (1,358.5 mD), reflecting strong hydrocarbon storage and flow capacity. In general, Reservoir M2 showed a balanced set of attributes, with a high hydrocarbon saturation of 40.1% and contributions from lower shoreface and channel sands. Reservoir M7 also showed robust permeability of 1,242.2 mD and hydrocarbon saturation of 44.0%, although with a slightly lower porosity of 19.9%. Gamma ray log motifs identified the shoreface and channel sands as dominant depositional environments, related to progradational and retrogradational stacking patterns. This study provides important insights into the hydrocarbon potential of the MAR Field, supporting optimisation of exploration and sustainable resource development within the Niger Delta. The findings highlight the role of detailed petrophysical analysis in reducing uncertainty and enhancing decision-making in hydrocarbon exploration.The Niger Delta Basin is a prolific hydrocarbon province with complex depositional environments influenced by alternating transgressive and regressive phases. This work focuses on the MAR Field, onshore Niger Delta, analysing reservoirs M1, M2, and M7 to evaluate the petrophysical properties and depositional environments critical for hydrocarbon exploration. We used gamma ray, resistivity, neutron, and density logs from four wells to assess key parameters such as porosity, permeability, water saturation, and hydrocarbon saturation. The analysis indicated favourable petrophysical properties across the reservoirs, with net-to-gross ratios greater than 60%. Reservoir M1 presented excellent porosity (23.8%) and permeability (1,358.5 mD), reflecting strong hydrocarbon storage and flow capacity. In general, Reservoir M2 showed a balanced set of attributes, with a high hydrocarbon saturation of 40.1% and contributions from lower shoreface and channel sands. Reservoir M7 also showed robust permeability of 1,242.2 mD and hydrocarbon saturation of 44.0%, although with a slightly lower porosity of 19.9%. Gamma ray log motifs identified the shoreface and channel sands as dominant depositional environments, related to progradational and retrogradational stacking patterns. This study provides important insights into the hydrocarbon potential of the MAR Field, supporting optimisation of exploration and sustainable resource development within the Niger Delta. The findings highlight the role of detailed petrophysical analysis in reducing uncertainty and enhancing decision-making in hydrocarbon exploration.