An Integrated Approach to Assess and Map Organic Shale Reservoirs- A Case History from Central Part of Lower Indus Basin, Pakistan
The present study is focused to evaluate and map the unconventional resources particularly, organic shale reservoirs in Lower Indus Basin Pakistan. As typical organic shale reservoirs are tight and very heterogeneous in nature. Advancement in technology has made it possible to exploit low permeability reservoirs worldwide. However, in Pakistan, cost effective price of commodity, optimized drilling and hydraulic fracturing are required to exploit the unconventional resources commercially. Prior to optimized drilling and hydraulic fracturing, delineation of sweet spots for organic shale resources is pre-requisite. Integration of geochemical and petrophysical data shows that shales of Middle and Lower Cretaceous horizons in the study area has retained enough hydrocarbon potential for exploration and are comparable to world known shale gas producing reservoirs. The estimated OHIP (gas equivalent) values shows that the Sembar Formation contains approximately 34 TSCF, Talhar Shale has 0.6 TSCF and 3.41 TSCF in shales of Massive Sand. Assessment shows that better OHIP values, reasonable resource density, fair to very good TOC values, moderate to good effective porosities, low water saturation, appropriate stress barriers, favorable fracking characteristics and high net pay of the Sembar Formation and lower shale of Massive Sand can be attributed for good and low risk targets for shale gas exploitation in the study area.
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