Fracture Gradient Analysis for Lockhart Formation at Kohat–Potwar and Nizampur Sub-Basins, Pakistan
Fracture Gradient Analysis for Lockhart Formation at Kohat–Potwar and Nizampur Sub-Basins, Pakistan
Rafiq Ali Khan1, Sajjad Ahmed1, Salim Raza2* and Shehla Gul1
ABSTRACT
The Lockhart Formation is a proven hydrocarbon reservoir in the Kohat–Potwar areas of Upper Indus basin. The geomechnical properties of the formation varies laterally and are not uniform due to which the drilling and field development is a serious challenge for petroleum companies. The Lockhart Formation is categorized into three lithological units to assess its geotechnical characteristics. The representative samples of the units are used for Unconfined Compressive Strength (UCS) tests to establish the fracture pressure and fracture gradient of the formation in Kohat-Potwar and Nizampur Sub-Basins and adjoining areas. Based on the UCS tests and extrapolation techniques, a benchmark value for fracture gradient of Lockhart Formation is derived that is 0.91 psi/ft. This value is very important parameter in drilling operations and can be used in proper designing of drilling fluid to avoid losses and subsequent kicks/blow out for safe and successful drilling of wells. The Lockhart Formation has reservoir potential in the stratigraphic units lying on the southern side of the Main Boundary Thrust (MBT), however it becomes Geomechanical more tighter and compacted towards east in Potwar sub basin and southward into Punjab plains, while the reservoir potential and fracture densities increases towards the Kohat Sub basin and frontier regions of Samana Ranges. The Kohat Sub basin and adjoining areas are contributing more than 50% of to the current oil production of Pakistan.
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December 2022
Vol. 41, Iss. 1, pp. 01-63
