Ukpebor Osahon¹, Maju-Oyovwikowhe Gladys Efetobore^2,

This study focuses on the identification and delineation of hydrocarbon-charged reservoirs in the SJ field of the Niger Delta Basin using an integrated rock physics modeling approach. The study design encompasses the integration of rock physics modeling, shear wave logs, and fluid substitution techniques. The research was conducted in the SJ field of the Niger Delta Basin, spanning from January 2022 to January 2023. Shear wave logs were empirically generated using the Castagna mud rock line relationship, and fluid substitution techniques were applied to obtain accurate log values for hydrocarbon-bearing intervals. P Impedance (Zp) and S Impedance (Zs) were inverted from P wave reflectivity (Rp) and S wave reflectivity (Rs) using a model-based inversion method. Several attributes, including μρ (mu-rho) and λρ (lambda-rho), were generated to discriminate between rock lithologies and differentiate gas-sand from wet-sand reservoirs, based on equations proposed by Castagna. Crossplot analysis of well log data was conducted to validate the presence of gas in the target zone. The results of the crossplot analysis confirmed the presence of gas in the target zone, providing support for the identification of hydrocarbon-charged reservoirs. Additionally, the generated attributes, such as μρ, λρ, and λ/μ, offered valuable insights into the distribution and extent of the gas reservoir. In conclusion, the integrated approach of rock physics modeling, shear wave logs, and fluid substitution techniques proved effective in identifying and delineating hydrocarbon-charged reservoirs in the SJ field of the Niger Delta Basin. The analysis of various attributes derived from inversion and crossplotting techniques facilitated the prediction of the spreading of the gas reservoir, highlighting the significant potential of this approach for reservoir characterization and development.

rock physics modeling, hydrocarbon-charged reservoirs, Niger Delta Basin, rock lithology, gas-sand reservoirs, reservoir characterization.