Reservoir Characterization, petrophysical analysis and prospect identification of ‘UQ’ field, southern Niger Delta, Nigeria

Abstract

The prospect evaluation of the UQ field using integrated 3D seismic and well log data from four wells (UQ-12, UQ-3, UQ-4 and UQ-5) has been carried out in this research. The study identified and assessed the plays, prospects, and components of the petroleum system within the ‘UQ’ Field to determine its actual potential and its economic viability for investment and development. The well logs and seismic data were incorporated to delineate four hydrocarbon bearing reservoirs and quantitatively estimate their prospectivity. The reservoirs (R_1, R_2, R_3 and R_4) were correlated across the field, with some appreciable reduction in net sand down dip. Structural analysis has been carried out using seismic data, which aided in the mapping of major, antithetic, and synthetic faults with four horizons (constrained by identified reservoir sand from the logs) that were gridded to create top structural maps. Petrophysical results using well log derived parameters and time-depth structural maps were obtained. Surface attributes, which are highly amplitude supported, were utilized to capture prospective zones better. The study showed that the R_1 reservoir has a very good porosity of 30%, an appreciable shale volume of 39%, and a high hydrocarbon saturation of 89% with an oil and gas phase. Similarly, the R_3 reservoir comprises shaly sands with very good average porosity of 27% and high average hydrocarbon saturations of 68%. Surface attribute analysis reveals the existence of hydrocarbon-bearing closures characterized by moderate to high root mean square amplitude and average energy values within R4 sand at the north eastern and south western parts of the field. These values are closely consistent with those obtained for R-2, which hosts the producing wells. Using these methods, this study has unravelled two new prospective zones with economical hydrocarbon volumes within the R_4 reservoir allowing for increased hydrocarbon volumes from the already producing field. Overall, the project aims to provide valuable insights into the technical, economic, and environmental aspects of the UQ field, which can contribute to informed decision-making and the sustainable development of Nigeria's energy sector.