Research On The Design Of Parameter Optimization And Engineering Application Of High Density Resistivity

In recent years, the high density resistivity is used more and more broadly. It is a kind of exploration method has the same basic principles that based on different conductivity of rock with traditional resistivity. It is studied on distribution of current conduction in electric field.Compared with other exploration methods, high density resistivity is more efficient and visual and has higher degree of automation. It is broadly used and has good results in metal and non-metallic mineral, engineering geological prospecting, geological hazards, karst exploration, archaeology, and many other fields.Some problems and shortcomings were found in the process of use high density resistivity instrument, for example, work process is not standardized, interpretation system is not perfect enough, the interference factors is not ruled out, resolution is low, the objectives presented in map and actual location has a large displacement etc. High density resistivity exploration technology and its application will not be improved until these issues are resolved. The paper focuses on practical application of high density electrical, simulates situation encountered in actual work and analyses the selection of acquisition parameters and frequency of inversion. It will provide experience for works.First, in the acquisition process, the choice of the parameters include: Array Mode, P-Distance, Pole Number, Separation Coefficient, Power supply mode. P-Distance, Pole Number and Separation Coefficient are the specific scope of the collection area; the power supply mode is selected based on the selected acquisition equipment for the different settings can be reasonable. Therefore the major component of the paper is the collection of Array Mode and determinate acquisition region using forward modeling analysis. The conclusions are as follows: (1) In the high density resistivity method to detect process, when using the Pole-Pole type detection devices, the acquisition area should be 2 ~ 3 times of the scope of the goal object; when using the P-Dpole type detection devices, the acquisition area should be more then 4 times of the scope of the goal object; when using the Wenner type detection devices, the acquisition area should be 3 ~ 4 times of the scope of the goal object; (2) In the high density resistivity testing, compared with the other two methods, the Pole-Pole type is more applicable to detecting geological osculatory .For a layered geological exploration, the Pole-Pole type and the Wenner type are satisfied to detecting. Pole-Pole type and Wenner type are all meet the requirements for cavity-shaped anomalous body. Pole-pole has good effect to anomalous body that horizontal range is large, and Wenner has good effect to anomalous body that vertical range is large.Secondly, in the data results in the inversion process, in respect of the current project high density resistivity method commonly used treatment methods (Zohdy inversion and the least square inversion),compared two inversion methods by the same model, and obtain the best inversion frequency. The conclusions are as follows:(1) About this two inversion software, Zohdy inversion frequency inversion in 5~7 times, as the best choice; the least squares inversion in the number of 3~5 times at the best option. Two methods are showing that, in the result, when the number of the inversion is too little, abnormal body will be not obvious, and at times too large, there will be distortion. Therefore, in practice, these conclusions can be used as reference, and several more should be compared and analyzed. (2) The least square inversion is more suited to the Pole-Pole type data and the Wenner type data; about the P-Dpole type data, the Zohdy inversion is better. (3) For different geological anomaly body, the least-squares method applicable to cavern inversion anomaly; Zohdy inversion method was applied to layered geological anomaly.By simulation analysis of model,the author finds out a reasonable selection in principle about the Design of Parameter Optimization of high density resistivity. In practice, it can avoid the mistake that is created by blindfold selecting the parameter.