The authors are grateful to the Directorate General for Petroleum Concessions (DGPC), Islamabad, Pakistan, for the release of the seismic and well data for this research. The National Centre of Excellence in Geology, University of Peshawar (Pakistan), is thanked for the provision of software and research facilities. The authors would also like to extend their thanks to the anonymous reviewers for their thoughtful reviews and suggestions to improve the quality of the manuscript. The Editor-in-Chief and Handling Editor of Acta Geologica Sinica (English Edition) are also thanked for their editorial review and comments.
The Tortonian–Calabrian strata of Offshore Makran (Pakistan) is investigated for the purpose of reservoir assessment. The stratigraphy and petrophysics indicate that the Neogene sediments have tight reservoir potential with porosities in the range of 3%–9% and 40%–50% water saturation. The mineralogical cross plots indicate a mixed lithology with an abundance of dolomite and calcite, together with minor quartz content and shale. The seismic interpretation demonstrates medium–high amplitude reflection patterns, mud diapirs coupled with onlapping strata and the occurrence of bottom simulating reflectors (BSRs). The BSRs are characterized by diminished amplitude, low continuity and exhibiting acoustic blanking zones. The high formation pressure results indicate overpressure zones, suggesting the occurrence of overpressured shales in the Jal Pari-1A. The presence of mud diapirs and gas chimneys are the result of tectonic forces acting at the junction of the Arabian, Indian and Eurasian plates, whereas, BSRs prove the existence of gas charged sediments supporting the formation of mud diapirism in the region. It is concluded that the high rates of sedimentation during the Neogene are likely to have contributed to the development of the high formation pressure. Revised mud weights, casing policies, pore pressure transients and geophysical inversion studies will help alleviate drilling risks in future exploration strategies.
Natasha KHAN, Awais ALI, Salahudin KHURSHEED, Kashif ALI, Muhammad SAEED.2023. Reservoir Potential Assessment of the Tortonian–Calabrian Sediments from Offshore Makran (Southwest Pakistan) through a Multidisciplinary Approach[J]. Acta Geologica Sinica(),97(1):163-175Copy