Abstract:
Khewra Formation/Sandstone is one of the most important hydrocarbon reservoirs within the eastern part of Potwar subbasin. Several authors have worked on the petrography and reservoir nature of Khewra Sandstone before but significantly less data is presented for these reservoir rock units especially on regional level. The current study is aimed to provide a regional facies correlation of the Khewra Sandstone. The study also aims to address the depositional and diagenetic controls on the reservoir nature of these sandstones. Exposure of the Khewra Formation has been studied in detail in five sections located within eastern and central part of the Salt Ranges. Five lithofacies including Parallel Laminated Sandstone Facies, Cross Bedded Sandstone Facies, Channelized Sandstone Facies, Amalgamated Sandstone Facies, and Shale/Clay Facies, has been identified in various outcrops. These facies are generally grouped into the three facies associations i.e., Delta Front Facies Association, ProDelta Facies Association, and Delta Plain Facies Association, demonstrating ancient deltaic deposited within western passive margin of the Indian Plate. Quartz is dominating in the Khewra Sandstone which tells about the well mature nature of the sandstone and categorized the sandstone to be of quartz Arenite classification. There is a dearth of feldspar which is caused by extreme chemical weathering of the source region, extensive transportation, diagenetic dissolution, alteration, and replacement. SEM analysis of researched samples indicate that the dissolution of unstable framework grains and volcanic lithics produces various clay minerals. The primary porosity is disturbed by the formation of clay minerals and cementation in pore spaces. The overburden pressure of the overlying formation and the chemistry of the clay minerals depicting the intermediate depth of burial of the Khewra Sandstone. Overall, the reservoir nature of these sandstones is appreciable not only in the eastern part of the basin but also in the central part and can be a potential target for the HC exploration in future activities.
Page(s):
25-27
DOI:
DOI not available
Published:
Journal: Sixth International Conference on Earth Science Pakistan, 25-27 June 2022 (Book of Abstracts), Volume: 0, Issue: 0, Year: 2022