Sand Production Prediction of a Reservoir in Niger Delta Using Empirical Relationships of Rock Mechanical Parameters from Wireline Logs (original) (raw)

2024, International Journal of Innovative Science and Research Technology

Sand production in the Niger Delta oil region is one of the most difficult challenges encountered during the many stages of field development planning, resulting in expensive drilling, production costs, and damage to oil installations. This geomechanical problem is expected because the Niger Delta Province is dominantly a loosed sandstone terrain, and the sand grains are highly friable. The study centres on employing empirical relationships of rock mechanical parameters from wireline logs to predict the vulnerability of lithologic formations to sand production in a reservoir in the Niger Delta. The reservoir five sandstone units were first recognized by using wireline logs (Gamma ray and self-potential logs), and the fluids were differentiated using resistivity, porosity, and density logs. The identified hydrocarbon prospecting sands were correlated throughout the five (5) wells. Gamma ray, resistivity and porosity logs were used for the correlation. Shear and compressive wave from the sonic log were then used to derive the rock mechanical parameters (Poisson ratio (ν), Young modulus (E), shear/rigidity modulus (G), bulk and matrix/grain moduli (Kb and Km), bulk and grain compressibility (Cb and Cr), Unconfined compression strength (UCS) and Critical flow rate pressure (CFRP). Four Prediction of Sand Production indicators (Formation sanding indicator method, Schlumberger formation sanding indicator, Bulk Elastic Modulus Ratio and Composite Modulus Estimation) derived from the rock mechanical parameters were used to adequately analyse sanding. The analysed reservoir exhibits sandstone units with lower value of Poisson ratio, Bulk modulus, Young’s modulus, Shear modulus and Unconfined compression strength of 2.3GPa, 0.26, 11.2GPa, 7.93GPa, and 16.73MPa, respectively. The formation shale exhibited higher values of Poisson ratio, indicative of its ductile nature that is resulting mostly from its clay content; the Bulk modulus, Young’s modulus, Shear modulus, and Unconfined compression strength exhibited high values (8.23 MPa,0.37,17.08 MPa, 25.02 MPa, 66.22 MPa respectively) while porosity and compressibility showed decreased values (0.07, 0.08 Mpa-1 respectively), leading to enhanced stiffness due to elevated moduli, hence less prone to deformation than the loosed sandstone units. The results of the four (4) Prediction of Sand Production models indicate a high risk of sanding during production of the investigated reservoir. A Critical flow rate pressure (CFRP) of 18.30 MPa is predicted to mitigate against sanding in the wells if the critical flow rate during production stays below 18.30 MPa. Thus, this research application of empirical relationships derived from rock mechanical parameters and wireline logs in predicting sand production can effectively aid informed investment decisions, risk assessment and performance optimization in Niger Delta reservoirs.