穆格莱德盆地苏夫焉凹陷阿布加布拉组沉积相特征及有利铀储集条件研究OA

The Muglad basin,as an important oil and gas-bearing basin in the Central African Rift Valley,features a complete set of continental sedimentary strata developed in the Lower Cretaceous Abu Gabra formation of the Sufyan sag.The provenance parent rocks in the northern part of the sag are mainly acidic granite and gneiss,which are homologous and isomorphic with the provenance parent rocks of uranium-bearing basins such as Bongor and Southern Chad in the Central African Rift system,and have high uranium content.It is believed that the study area possesses the basic geological conditions for the development of uranium bearing horizon.However,current research on the relationship between the sedimentary facies characteristics of the Abu Gabra formation and uranium bearing horizon development in this region is relatively weak,and the favorable sedimentary conditions for uranium bearing horizon development are not yet clear.Based on this,this paper takes the Abu Gabra formation in the Sufyan sag as the research object,combines drilling and seismic data,and explores the relationship between the sedimentary facies characteristics of the Abu Gabra formation and uranium bearing horizon development through sequence stratigraphic division,sedimentary facies identification,and analysis of favorable mineralization conditions.This research indicated that the Abu Gabra formation can be divided into five third-order sequences,with sedimentary facies types mainly developing into meandering river delta facies,braided river delta facies,fan delta facies,and shallow lacustrine facies.Paleoclimate and hydrodynamic conditions provided a favorable material transport environment for the development of uranium bearing horizon.The northern gentle slope and southern fault slope control the distribution pattern of sedimentary facies,thereby affecting the spatial distribution of favorable uranium bearing horizon.The sand bodies in the northern meandering river delta facies are well developed,with a good sand-mud interbedding structure,high porosity and permeability of the sand bodies,and good bearing horizon performance,making it the optimal facies belt for uranium mineralization.At the same time,the strata themselves have certain reduction conditions,providing a basic guarantee for the enrichment of uranium elements.The research results clarify the correspondence the sedimentary facies characteristics of the Abu Gabra formation,discussion on the favorable effects of sedimentary facies distribution,lithological combination,and other factors on uranium bearing horizon development,and provide a basic reference for the evaluation of uranium resource potential and subsequent related research in this region.