Lithium enrichment pattern and resource potential in saline lacustrine shale and prospects for co-production with shale oil

Based on the survey of saline lacustrine shales in the Permian Lucaogou Formation and Fengcheng Formation in the Junggar Basin, it is found that the sweet intervals of these shale oil strata are enriched with lithium. In certain intervals, lithium contents reach up to 700 μg/g, with produced water concentrations estimated to 517.2 μg/g—an underexplored resource with considerable potential that has yet to receive adequate attention. The sedimentary environment, depositional process, and geochemical characteristics of these intervals were analyzed, indicating that lithium enrichment in saline lacustrine shale is controlled by multiple factors during deposition and diagenesis. The salinity of lake water during sedimentation plays a key role in lithium accumulation, with lithium primarily concentrated in carbonate-rich intervals, and diagenesis further affects its distribution. To assess the potential for lithium co-production in shale oil development, future research should be based on the enrichment mechanisms of lithium and hydrocarbons in lacustrine shales, predict the distribution patterns of oil and lithium-rich intervals, and evaluate the economic feasibility of an “oil–lithium integrated sweet spot”. Efficient lithium extraction and environmental protection technologies need to be explored to optimize resource development. Saline lacustrine shale oil development not only ensures stable oil and gas supplies but also, if lithium co-production is realized, could enhance China's lithium security, contributing significantly to the country's energy transformation.