Predictive Analysis of Sand Production and Flow Implications using Petrophysical-Geomechanical Properties: A case of “ANY” Field, Niger Delta

Abstract

A predictive analysis of sand production and flow implications using petrophysical-geomechanical properties: A case of the 'ANY' field, Niger Delta, was carried out. Datasets, including well logs and 3-D seismic, were used to investigate the geomechanical properties of the field and predict sand production based on the results obtained. Sand production is expected because the Niger Delta Province is predominantly a loose sandstone terrain, and the sand grains are highly friable. The study centers on employing empirical relationships of rock mechanical parameters from wireline logs to predict the vulnerability of the reservoir formations to sand production. The four reservoir units (A1, A2, A3, and A4) were first recognized by using wireline logs (gamma ray), and the fluids were differentiated using resistivity, neutron porosity, and density logs. We correlated the identified hydrocarbon prospecting sands across all three wells. Shear and compressive waves from the sonic log were then used to derive the rock mechanical parameters (Poisson ratio (ν), Young modulus (E), shear/rigidity modulus (G), bulk modulus (Kb), bulk compressibility (Cb), and unconfined compression strength (UCS)). Five sand production methods (porosity, acoustic wave travel time, sand production index (B), Schlumberger sand production index (SI), shear modulus to bulk compressibility ratio (G/Cb)) derived from the rock mechanical parameters were used to adequately analyze sanding. The analyzed reservoir exhibits sandstone units with a higher average value range of Poisson ratio, bulk modulus, Young’s modulus, shear modulus, and unconfined compression strength of 0.26 to 0.33, 15.29 to 20.90 MPa, 15.52 to 29.23 MPa, 5.84 to 11.56 MPa, and 22.45 to 29.23, respectively. The reservoirs exhibited higher values of the Poisson ratio, indicative of their ductile nature that is resulting from shale intercalations, which is evident in the moderate net to gross (NTG) ratio, leading to enhanced stiffness due to elevated moduli, hence less prone to deformation. The results of the five (5) predictions of sand production models indicate a very low risk of sanding during production of the investigated reservoirs. Thus, this research application of empirical relationships derived from rock mechanical parameters and wireline logs in predicting sand production has effectively deduced that the reservoirs in ANY field were highly compacted and consolidated, and therefore problems associated with sand production (sanding) during hydrocarbon extraction in this field are ruled out or almost unlikely.