Abstract:
The present study is focused on the analysis of hydrocarbon resource potential of
Chichali Shale and Samana Suk Limestone in Kohat Sub-basin, Pakistan based on openhole wireline log qualitative and quantitative analysis in well of Makori-01, Manzalai-02
and Maramzai-02. The analysis reveals Chichali Formation comprises two main Shale
units with the non-Shale unit in between. The first zone of Shale demonstrates good
outcomes regarding unconventional reservoir properties with TOC of 1.3 to 1.91% and
Shale porosity of 5.1% to 9.6%. While the second zone shows TOC of 0.52 to 0.73% and
Shale porosity of 6.4% to 8.71%. The mineralogical assessment shows Chichali
Formation mainly bears Mixed layer clays, Illite, Glauconite and Mica bearing Shale.
Mechanical properties assessment through compressional and Shear Sonic log favours
Chichali Formation as good brittleness possessing Shale making it an optimistic target
for hydraulic fracturing. The Samana Suk Limestone shows good hydrocarbon Saturation
with poor porosity and permeability. The Porosity ranges from 1.54% to 3.58% with
average permeability of less than 1 mD. The permeability categorises the Samana Suk
Formation as a tight reservoir. The analysis shows Samana Suk Limestone bears 23.02%
of Sw in Manzalai-02, 27.6% in Makori-01 and 44.06% in Maramzai-02 well. Mapping
reveals the source rock potential of the Chichali Formation in terms of organic richness
increases from E to W in zone-1, and from SE to NW in zone-2. While Shale porosity
increase from NE to SW. Moreover, Samana Suk Limestone illustrates enhancement in
reservoir attributes like Sw, PHIA and PHIE while traversing from NE to SW and
degradation in hydrocarbon saturation from NE to SW.
