Double-provenance depositional model and oil-gas exploration significance in Shahejie Formation, the southern segment of Liaoxi Uplift

The development level of Paleogene reservoirs has always been a key factor restricting exploration breakthroughs in the southern segment of the Liaoxi Uplift. We used basic data from drilling, apatite fission track analysis, and three-dimensional seismology to focus on the reservoir development of the Shahejie Formation evolution analysis and semi-quantitative characterization of paleogeomorphology were carried out to predict the Shahejie Formation reservoir in the target area. Results indicate that the southern segment of the Liaoxi Uplift mainly experienced four evolutionary periods, i.e. tectonic uplifting in the early Cenozoic, tectonic subsidence during Shahejie Age in the Paleogene, tectonic inversion during Dongying Age in the Oligocene, and tectonic finalization in the Neogene. The fault system in the area can be divided into three types: long-term active type, early faulting early declining type, and late faulting late declining type. The Liaoxi Sag congenital source supply condition of "basin full and sand overflow", and the segmented characteristics of tectonic evolution have led to the formation of a special "chain island bay" sedimentary model in the southern segment of the Liaoxi Uplift. It can provide material sources for the surrounding area, form near source sedimentary bodies, and also form a large accommodating space, converging the overflowing sand bodies from the Liaoxi Sag, forming a double-provenance sedimentary model on the Liaoxi Uplift. The above understanding has effectively promoted the evaluation of the Lvda 4-3 Oilfield and has good reference significance for oil and gas exploration in uplift area.