Reserch On Improved Sparrow Search Algorithm For Self Potential Data Inversion And Application To Sandstone-type Uranium Deposits Exploration

Self potential(SP)method is a natural source geophysical exploration method to measure the potential difference generated by electrochemical,electrokinetic and thermal potential factors,which has the characteristics of low cost and simple operation steps.The conventional inversion algorithms are divided into local optimization and global search algorithms,but the gradient-based local optimization algorithm is difficult to find the global optimal solution and the inversion effect depends on the initial model construction,while the traditional global search algorithm has the disadvantages of slow convergence,easy to fall into local extremes and instability.In order to improve the SP method data inversion capability and practical application effect,this paper discusses several types of metaheuristic algorithms for SP data inversion,proposes a series of strategies to improve the algorithm SP data inversion capability,and carries out the inversion application research on the measured data based on the clarification of the natural electric field source in Zhajisitan uranium mining area.The research work begins with a review of the theory of SP forward modeling and the establishment of a computational model for forward simulation.Then,the research work analyzes and compares the SP data inversion capabilities of three representative metaheuristics(genetic algorithm,particle swarm algorithm and sparrow search algorithm).Based on the analysis results,the sparrow search algorithm is improved by Tent chaos mapping with backward learning,introducing dynamic adaptive weights and incorporating adaptive t-distribution variances,and the improved algorithm is introduced into the SP data inversion application for the first time to improve the inversion effect.Finally,the algorithm before and after improvement is used to invert the synthesized data of single source and multi-source models with noise interference,as well as the measured spontaneous potential anomaly data of buried metal barrel,Surda area and LUSI dam,to verify the effectiveness of the improved method.The result shows that the proposed improved algorithm could overcome the shortcomings of the original algorithm in the inversion process,such as slow convergence rate in the late iteration,easy to fall into the local extreme value,and has stronger anti-noise ability and better inversion accuracy and stability,which reflects the advantages of the improved method.The method is applied to the northwest of Zhajisitan uranium deposit,the geological and hydrogeological conditions of the mining area are summarized,and the formation mechanism of SP anomaly of sandstone-type uranium deposit in interlayer oxidation zone is elaborated.Based on the analysis of the characteristics of three SP abnormal curves in the northwest part of the mining area,whether the strata contain ore or not is predicted.The improved sparrow search algorithm is used to invert the measured data,and the spatial location of the underground abnormal body is delimited.The research work could effectively delineate the spatial location of sandstone type uranium deposit in interlayer oxidation zone and provide technical support for the exploration of this kind of uranium deposit.The results show that the improved algorithm can be well applied to the quantitative interpretation of spontaneous potential data or generalized to solve other geophysical inverse problems.