Fracture and Fracture Pressure Analysis of the Carbonate Reservoir: Implications for Hydrocarbon Exploration and Drilling in Pakistan

Abstract

In this study, the fracture and fracture pressure analysis of the carbonates of the Lockhart Formation from the Makhori-1 well in Kohat Basin is presented. The fracture density, connectivity, is explained while fractured porosity range is 0.77–2.18% and the permeability ranges are 1.32–7.97 Darcie’s. The statistical plots of Makhori 1 Well confirm the continuous conductive fractures having strikes in EW, NS, and NE-SW and NW-SE directions. The discontinuous conductive fractures dominantly strike in the NW–SE and WNW–ESE directions. The induced fractures trend in the NNE-SSW direction, whereas the breakout shows a trend in the ENE-WSW. The FMI based open fracture porosity and fracture aperture range from 0 to 0.1% and 0.001–0.04 mm. The 4585 psi formation fracture pressure is also calculated on the basis of unconfined compression strength test and mud losses. The pore pressure gradient for the Lockhart Formation is 0.55 psi/ft, and the fracture gradient is estimated to be between 0.9 and 0.94 psi/ft. Therefore, the safe drilling window is 0.55 psi to 0.910 psi/ft. The minimum fracture gradient of 0.910 psi/ft should be used for all calculations and estimations in drilling plans, mud designs, and hydraulic fracture plans in the study area.