Distribution of Permian and Triassic strata in the Laoshan Uplift, Southern Yellow Sea, using seismic attributes

Abstract

The Laoshan Uplift (LSU) in the South Yellow Sea Basin of the Lower Yangtze Plate is a potential site for hydrocarbon exploration; thus, determining the strata attributes and distribution is imperative. Tracking a wide range of seismic reflection horizons for lateral comparisons is challenging because the first well (CSDP-2) encountered in the Paleozoic strata of the LSU is located in a structurally complex deformation zone and has yielded poor seismic data quality. In this study, we present a novel approach to seismic horizon tracking in areas with few or no wells and adopt a cross-regional analogy and inverse analysis method to track the seismic horizon. Seismic attribute characteristics of the marine strata of the LSU were compared with the seismic horizons calibrated in the Wx1 well in the stable Qingdao Depression (QDD), and horizontal tracking was performed. An inverse analysis was then performed on the CSDP-2 well area to predict the distribution of marine strata in the LSU. The results revealed that the Permian and Triassic strata of the LSU and QDD have similar seismic attributes. Finally, the seismic horizon of the LSU was tracked horizontally based on a comparison of the seismic attributes of the LSU and QDD. Previous studies showed that seismic reflection horizons are difficult to calibrate, and the marine strata attributes in the LSU remain controversial. This study adopted a cross-regional comparison and inversion analysis method to perform a seismic multi-attribute comparison based on the calibrated results of the QDD for the Wx1 well. The remaining Permian and Triassic strata lie almost entirely within the LSU. Moreover, the maximum reported thicknesses of the Upper Permian and Lower-Middle Triassic strata in the LSU were approximately 500 and 2750 m, respectively. Our findings will aid in the exploration and evaluation of early hydrocarbon resources in the LSU.