Reservoir Potential Evaluation of the Middle Paleocene Lockhart Limestone of the Kohat Basin, Pakistan: Petrophysical Analyses

• Published in: International Journal of Economic and Environment Geology Vol. 11; no. 1; pp. 1 - 9
• Main Authors: Khan, Nasar, Ahmed, Imran, Ishaq, Muhammad, Jan, Irfan U, Khan, Wasim, Awais, Muhammad, Salam, Mohsin, Khan, Bilal
• Format: Journal Article
• Language: English
• Published: Society of Economic Geologists and Mineral Technologists 06-07-2020
• Subjects: kohat basin; lockhart limestone; paleocene; reservoir; shakardara
• ISSN: 2223-957X; 2223-957X
• DOI: 10.46660/ijeeg.Vol11.Iss1.2020.404

The Lockhart Limestone is evaluated for its reservoir potential by utilizing wireline logs of Shakardara-01 well from Kohat Basin, Pakistan. The analyses showed 28.03% average volume of shale (Vsh), 25.57% average neutron porosity (NPHI), 3.31% average effective porosity (PHIE), 76% average water saturation (Sw), and 24.10% average hydrocarbon saturation (Sh) of the Lockhart Limestone in Shakardara-01 well. Based on variation in petrophysical character, the reservoir units of the Lockhart Limestone are divided into three zones i.e., zone-1, zone-2 and zone-3. Out of these zones, zone-1 and zone-2 possess a poor reservoir potential for hydrocarbons as reflected by very low effective porosity (1.40 and 2.02% respectively) and hydrocarbon saturation (15 and 5.20%), while zone-3 has a moderate reservoir potential due to its moderate effective porosity (6.50%) and hydrocarbon saturation (52%) respectively. Overall, the average effective porosity of 3.31% and hydrocarbon saturation of 24.10% as well as 28.03% volume of shale indicated poor reservoir potential of the Lockhart Limestone. Lithologically, this formation is dominated by limestone and shale interbeds in the Shakardara-01 well. Cross-plots of the petrophysical parameters versus depth showed that the Lockhart Limestone is a poor to tight reservoir in Shakardara-01 well and can hardly produce hydrocarbons under conventional drilling conditions.