Discovery of Mesozoic strata in the eastern region of offshore Pakistan and its oil and gas significance

After more than 60 years of oil and gas exploration in the offshore areas of Pakistan, the primary focus has long been on the Cenozoic strata. The distribution of Mesozoic formations and the tectonic evolution remain unclear. The eastern offshore areas of Pakistan underwent a complex tectonic-sedimentary evolution during the Neogene. Influenced by the Himalayan uplift during the Neogene, a significant amount of detritus from continental margin deposited, making it an excellent location for studying numerous fundamental scientific questions. Due to the impact of regional volcanic rocks in the late Cretaceous, there has been considerable controversy regarding the existence and distribution of the Mesozoic strata in the region, significantly hindering the regional oil and gas exploration activities. Based on high-quality 2D geological profiles, overcomes the previous shielding effect of volcanic rock layers. By means of seismic reflection interface delineation, analysis of seismic wave group characteristics, and layer velocity analysis, the extensive distribution of the Mesozoic strata in the eastern offshore areas of Pakistan was clarified. The Mesozoic formations, controlled by intense extensional faulting in the same period, are segmented within multiple secondary basins of varying scales, forming a paleo-tectono-geographic pattern of alternating uplifts and depressions. The overall thickness ranges from 800 to 10000 m, thicker in the southeast and thinner in the northwest. Overlapping towards the north and west, the maximum sedimentary thickness is located in the southeast and northwest regions of the study area. The stratigraphic unit was confirmed as an important hydrocarbon source rock layer in the onshore of the lower Indus River Basin, which effectively expanded the future directions and potential value of oil and gas exploration in the offshore areas.