Dahmane Bah

Boumerdes University, Algeria

Reservoir Property Evaluation Using Petrophysical Data: Insights from the Banda Field, Mauritania’s Coastal Basin

Biography

Abstract

This study presents a comprehensive petrophysical evaluation of the Banda Field, located in Mauritania’s Coastal Basin, with a focus on the Banda-2 well1. The primary aim is to assess the reservoir properties through detailed petrophysical data, including core and log analysis, to provide insights into the field’s hydrocarbon potential and its suitability for gas injection. The research is based on a range of well log data (including GR, Resistivity, Density, Neutron, and Sonic logs) and core samples, with an emphasis on fluid substitution, porosity, permeability, and water saturation1. The petrophysical evaluation incorporates core analysis, conventional log analysis, and advanced methodologies, including Formation Evaluation While Drilling (FEWD) and thin bed analysis using the 3DEX tool. Fluid substitution and pressure interpretation provide additional insights into the distribution of gas, oil, and water columns. The evaluation parameters, such as Vshale, lithology, porosity, and permeability, are derived from the logs, Porosity and water saturation were calculated with the LOGIC User Program (SATCPOBM) which takes invasion and HC effects on the density log in to account. while core data supplement the porosity and permeability estimates. The Banda-2 well intersected a significant gross reservoir thickness with a combination of gas, oil, and water-bearing sands. The petrophysical analysis indicates high-quality sands with excellent porosity and permeability, particularly in the gas-bearing zones. The well intersected 289.5 m gross (91.8 m net) of reservoir sands, bearing gas, oil and water. A gross gas column of 116m, and an underlying oil rim of ~12m were penetrated. All sand bodies intersected in the well appear to share a common pressure system that is consistent with the pressures measured in the Banda-1 well2. Fluid contacts interpreted from logs and pressure data (GOC ~2464mTVDSS, FWL ~2447mTVDSS) are consistent with those observed in Chinguetti-4-3 (Banda-1), Numerous clean, blocky, stacked channel systems were intersected by the well. The results highlight the variability of reservoir quality, with clean, blocky sands exhibiting high porosity and permeability3, while thin beds and conglomerate intervals show reduced flow potential. The presence of slumped intervals complicates the interpretation of certain layers, but the combined use of 3DEX and conventional methods provides a clearer understanding of the reservoir’s architecture3. The integration of fluid substitution models and pressure data further refines the estimation of reservoir properties, supporting the development of a more accurate reservoir model.

The Banda Field exhibits significant hydrocarbon potential, with high-quality sands offering substantial deliverability and injectivity. The study provides a thorough understanding of the petrophysical properties, critical for effective reservoir management and future development. The results will contribute to optimizing production and enhancing recovery in this gas-injection project.

Keywords: MSGBC, Seismic 3D, VSP Calibration, Salt Tectonics