1.Xi’an Center of Geological survey,China Geological survey,Xi’an;2.Green Development Institute of Western China,China Geological survey,Xi’an;3.China Geological survey
project of China Geological Survey (No. DD20221774)
[Objective] Ordos Basin is an important energy base in China, with rich oil, natural gas and coal resources, bauxite, uranium and other mineral resources. Bauxite is abundant around the basin, but there is little research on deep bauxite in the basin. Oil and gas drilling shows that the basin is rich in bauxite resources, with a buried depth of one hundred to four kilometers. If the exploration and mining of deep bauxite can be realized, the situation of insufficient bauxite resources in China will be greatly alleviated. [Methods] The geological characteristics and petrophysical characteristics of bauxite in Tongchuan area, Ordos basin are studied in this paper. [Results] First, the deep bauxite in the basin has obvious electrical characteristics, which is characterized by "four high and two low". With reference to oil and gas logging interpretation methods, bauxite identification standards and bauxite logging interpretation models can be established to obtain diaspore content and complete the evaluation of bauxite; Second, the distribution of bauxite in the basin is controlled by the palaeogeomorphology of the Paleozoic Majiagou Formation, and the ore bed is stably distributed, with considerable resources and great exploration potential; Third, bauxite belongs to sedimentary rock, which has certain porosity and permeability, and presents sandwich structure. The bauxite ore bed with high permeability is often surrounded by clay rock with low permeability, meeting the geological conditions of in-situ solution mining; Fourthly, according to stress sensitivity analysis, bauxite is compressible, and new pores or cracks will appear under certain stress, which can further improve the permeability of the ore bed and increase the possibility of in-situ leaching mining of bauxite. [Conclusions] Logging technology can be used to evaluate the deep bauxite resources in Ordos Basin. In combination with the petrophysical characteristics of bauxite, in-situ leaching mining can be considered for bauxite.