Study on reservoir structure and mineralization type of the sandstone uranium deposits, southern Songliao Basin

Exploring the sandstone-type uranium deposits in the DL area, located in the southern Songliao Basin, our research focuses on the sedimentological characterization, structure of the uranium reservoir and processes of uranium mineralization. Through drilling data statistics and systematic sampling analysis, a uranium reservoir heterogeneity map was drawn, which finely depicted the geometric shape and complex structure of the Yaojia Formation uranium reservoir, and fully demonstrated the quantitative heterogeneity of uranium reservoirs. The results show that the gray sand body primarily retains its original color, while the lower oxidation zone underwent modification by strong supergene fluid activity after the deposition, and transforming into an epigenetic oxidation zone. The ore bodies are mainly distributed in the bifurcation of the channel sand body, and along the edge of the channel sand body where the thickness transitions suddenly from no barrier layer to the presence of barrier layer, rather than in the center of the channel. Their plate-like shape is controlled by the redox interface. Comprehensive analysis shows that the mineralization of supergenetic fluids can be divided into two stages: the enrichment of the ore—bearing host rocks of the Yaojia Formation during the Late Cretaceous and the superimposed transformation of supergenetic fluids. By comparing the controlling effect of reservoir structure on uranium mineralization in DL area, three prospecting target areas were optimized in the BL area, providing a theoretical foundation for future exploration work.