Objective The Songliao Basin is not only an important petroleum base but also a crucial uranium resource base in China. The oil−uranium symbiosis mechanism has become a research focus. Among related studies, horizon determination, structural division, and particularly the distribution characteristics of sandstones in the Sifangtai Formation (the main ore−bearing horizon) are of great significance for analyzing the distribution pattern of oil and uranium as well as the mineralization mechanism.

Methods Based on 3D seismic exploration, this study utilized the acquired 50 km² 3D seismic data volume in the GQ area. Through data processing and interpretation technologies such as fine data processing, logging curve reconstruction, and joint horizontal slicing, the thickness and planar distribution characteristics of the upper, middle, and lower sandstone members of the Sifangtai Formation were revealed. Furthermore, mineralization−related information closely associated with sandstone−type uranium deposits was interpreted, including the "mud−sand−mud" stratigraphic structure, structures, and lithology−lithofacies. Finally, the 3D geological structure of the basin and the development characteristics of ore−bearing sandstone bodies in the study area were clarified.

Results It is found that in the study area, the burial depth of the Sifangtai Formation is shallower in the south and deeper in the north, while its thickness is thinner in the south and thicker in the north. The sandstone body at the bottom of the lower member of the Sifangtai Formation has a large thickness, good stability, and favorable connectivity. Together with the fine clastic sediments at the bottom of the middle member of the overlying Sifangtai Formation and the fifth member of the underlying Nenjiang Formation, it forms a stable "mud−sand−mud" stratigraphic structure, which is conducive to mineralization.

Conclusions By comprehensively analyzing the ore−forming factors of sandstone−type uranium deposits, it is considered that the areas with sandstone body thickness of more than 20 m are favorable for mineralization. Based on this, six uranium prospecting target areas were delineated, and five of them were verified by subsequent drilling. 3D seismic exploration plays a prominent role in interpreting mineralization−related information closely associated with sandstone−type uranium deposits, such as the "mud−sand−mud" stratigraphic structure, structures, and lithology−lithofacies. It is a key geophysical method for achieving breakthroughs in sandstone−type uranium prospecting.