PETROPHYSICAL EVALUATION AND DYNAMIC MECHANICAL PROPERTIES OF SHINAWARI FORMATION FOR UNCONVENTIONAL HYDROCARBON POTENTIAL IN KOHAT SUB-BASIN, PAKISTAN

Abstract

Unconventional reservoirs are fine-grain sedimentary rocks, rich in organic shale having trap gas considered a source, reservoir, and seal rock. Shales can be a good reservoir despite having low porosity and permeability and it can be a tempting target for hydraulic fracturing, exploration industries target those fine-grained sedimentary rocks units that may serve as oil/gas reservoirs, thereby comprising of unconventional energy resources throughout the world. TOC content and brittle indices of Shinawari Formation were investigated in the research area of Chanda Oil Field situated in Shakardara, district Kohat, Khyber Pakhtunkhuwa, to predict the capability for unconventional hydrocarbon potential. TOC values gained through Schmoker and Passey methods from interpreting the logs showed that there is variation in the organic richness of Shinawari Formation. TOC values range from 0.2 to 2.4% suggest that Shinawari shale values lie in poor to good source rock and vitrinite values range between 1.16 to 1.35% suggest that Shinawari Formation is thermally mature to produce hydrocarbons. The Brittleness Index (BI) was calculated based on calibrated elastic parameters ranging from 0.3 to 0.56Pa for Chanda-01 and 0.3 to 6.4Pa for Chanda Deep-01. Brittle (BI>0.4Pa) and ductile (BI<0.4Pa) sections were identified based on BI for the optimization of hydraulic fracture treatment. The results extracted from the investigation of Shinawri Formation classify the intervals in the brittle-ductile zone thus making it a suitable target for hydraulic fracturing.