Reservoir Geomechanics Parameters Estimation Using Well Logs and Seismic Reflection Data: Insight from Sinjhoro Field, Lower Indus Basin, Pakistan

Abstract

Nowadays, the failure to understand a hydrocarbon field’s geomechanics signifies an expensive risk in several complex drilling, well completion, and exploitation processes. Thus, the precise estimation of reservoir geomechanical parameters can lessen that risk and provide benefits all the way through oil and gas field’s lifespan. Several factors like compaction of sediments, lithology characteristics, overburden, hydrocarbon and capillary entry pressures add substantial effects to cause of abnormal pressure and resultantly affect the well design and stability. The aim of current study is to compute geomechanical properties such as overburden pressure and vertical effective stress and finally to define the lower and upper bounds (breakout and breakdown limits) of safe mud weight window by determining the pore pressure and fracture gradient for pre-drill planning in future exploration and real time monitoring in the Sinjhoro Field, the Lower Indus Basin of Pakistan. Current studies examined the wireline logs data of four wells drilled in the Cretaceous reservoir sands and seismic reflection data-based P wave velocity functions and describes a workflow for reliable estimation of geomechanical parameters. Our results revealed that high pore pressure (5000–7000 Psi) is predicated at reservoir zone and it increases in southeast directions. On the basis of pore pressure and fracture pressure, both lower (5388.89 Psi) and upper (6572 Psi) bounds for safe mud weight window are defined for safe drilling and well stability that will help future exploration and development in the Sinjhoro field. Both overburden pressure and vertical effective stress increase uniformly with depth but spatial variations are nonlinear and increasing in northwest directions. The present work will support the petroleum industry by reducing the borehole drilling cost with no compromising on environment and safety concerns.