Geomechanics of Ubaku Field in the Niger Delta using 1-D Mechanical Earth Molding (MEM)

Abstract

This research utilized the Mechanical Earth Modeling approach to evaluate the geo-mechanical properties of the Ubaku field in the Niger Delta for Enhanced Oil Recovery and ensuring maximum resource extraction while minimizing environmental and operational risks. The geo-mechanical properties evaluated include Young’s Modulus whose value is between 1.67 to 4.04Mpsi, Poisson’s ratio ranges between 0.25 to 0.36, Bulk modulus is between 1.64 to 2.13Mpsi, Shear modulus is between 0.65 and 1.66Mpsi, VpVs ratio is between 1.78 to 2.66, S-Hmin is between 6668.32 to 7722.53psi, S-Hmax is between 16011.26 to 23991.93psi, overburden stress is between 8805 to 10567.85psiHydrostatic pressure is between 5044.57 to 5112.43psi and fracture pressure lies between 6832.96 to 6930.91psi. With a Young’s Modulus indicating moderate stiffness and Poisson’s ratio showing mixed brittleness and ductility, the reservoir is suitable for hydraulic fracturing. Stress anisotropy (S-Hmax vs. S-Hmin) values suggests fractures will propagate along preferred orientations, which must be considered in fracturing design. Variability in shear and Young’s modulus highlights zones that may be prone to instability. Proper mud weights and casing designs are essential to mitigate collapse or over-fracturing risks. With overburden stress exceeding horizontal stresses, fractures are likely to propagate horizontally, ensuring containment within the target zone and minimizing caprock breach risks. The reservoir exhibits favorable conditions for operations such as hydraulic fracturing and production, with a mix of brittle and ductile behaviors.