Evaluation of Rock Mechanical Properties and Their Influence on Hydraulic Fracture Design in Tight Sandstone Reservoirs of the Sokoto Basin, Kebbi State

Hydraulic fracturing in tight sandstone reservoirs requires accurate characterisation of rock mechanical properties to design fracture treatments that achieve the necessary fracture geometry, conductivity, and propped length for economic well deliverability. This study evaluates rock mechanical properties and their influence on hydraulic fracture design in tight sandstone reservoirs of the Sokoto Basin, Kebbi State, North West Nigeria. Triaxial compression tests and Brazilian disc tests were performed on twenty-four core plug samples from two boreholes intersecting the target formation. Young's modulus, Poisson's ratio, uniaxial compressive strength, and tensile strength were measured as functions of confining pressure and compared with dynamic elastic properties derived from sonic log measurements. A dynamic-to-static conversion function was calibrated using the experimental data. Minimum horizontal stress was estimated using the poroelastic horizontal strain model, incorporating the calibrated static elastic properties and formation pore pressure from pressure gradient tests. Hydraulic fracture simulations using Kinetix software were run to evaluate fracture geometry as a function of treatment volume, proppant concentration, and injection rate for two selected candidate wellbores. Results indicate that optimum fracture half-lengths of 120 to 180 metres can be achieved with treatment volumes of 800 to 1,200 barrels of slurry and proppant concentrations of 2.5 to 4 pounds per gallon. Keywords: rock mechanical properties, hydraulic fracture, tight sandstone, Sokoto Basin, Kebbi State.