Seismic stratigraphy and attributes application for imaging a Lower Cretaceous deltaic system: Sukkur rift zone, Lower Indus Basin, Pakistan

Abstract

This study is aimed at imaging the deltaic depositional sequences in the Sukkur Rift Zone (SRZ) of the Lower Indus Basin, Pakistan. The seismic sequence, back stripping, and thin-bed wedge modeling tools were applied to the gas field of the SRZ to develop the foundations for tectonics and sedimentary processes in the distribution of potential hydrocarbon reservoirs. The conventional seismic method does not have the capability to predict the quantitative aspects of deltaic systems. Five passive seismic sequences were utilized for mapping the sediments of the foreland margin within the Indian Plate. The subsidence curves showed that the tectonic activity had occurred between the Lower Cretaceous and Eocene depositional sequences. The maximum tectonic activity was observed during 50–70 Ma within the SRZ. The upper shoreface depositional system was modeled by a thin-bed wedge model at enhanced thicknesses of 52 m, 55 m, 56 m, 57 m, 58 m, and 61 m. Thin-bed wedge modeling has provided solid evidence and implications for the development of stratigraphic traps within the upper shoreface depositional system. The thin bed wedge model remained an accurate tool for the prediction of direct hydrocarbon indicator (DHI) within the tectonically-influenced depositional systems. Hence, the presented research work can be used as an analogue for the development of tectonically and stratigraphically stable fairways within the Asian Basins and similar geological settings.