Background grid adaptive segmenting method in DC resistivity no-unit method

Abstract

The invention provides a background grid adaptive segmenting method in a DC resistivity no-unit method. The method comprises the following steps of determining distribution condition of medium, abnormal member, landform, electrode and the like in a two-dimensional ground electric model, establishing a DC resistivity no-unit method calculating domain, and utilizing an irregularly distributed node discrete ground electric model; covering the calculating domain by means of a small number of rough and simple initial quadrangular grids, setting a control value which guides adaptive segmentation, and performing adaptive segmentation by the background grid according to the control value and a node distribution condition; arranging ng Gaussian integration points xg in each background grid, and obtaining a no-unit method equation set of the region; solving the equation set for obtaining a node electric field value, and calculating the vision resistivity parameter of a viewing point. The methodcan be based on any node distribution discrete model. High adaptability for any complicated ground electric model is realized. The background grid adaptive segmenting method improves value stability and computing efficiency in routine DC resistivity no-unit method forward calculation.

Description

technical field [0001] The invention relates to a DC resistivity forward modeling method in the field of exploration geophysics, in particular to a high-precision, high-flexibility, high-adaptability and high-efficiency unit-free forward modeling method for complex geoelectric models. Background technique [0002] DC resistivity prospecting is an important method in geophysical prospecting, which is widely used in solid mineral resource prospecting, hydrogeological prospecting, environmental governance and monitoring, engineering geophysical prospecting and other fields. The measured apparent resistivity has a direct relationship with the resistivity of the underground medium. By artificially supplying electricity to the underground, observing the apparent resistivity on the surface or in the well can judge the distribution of underground resistivity anomalies. With the development of DC resistivity exploration technology, there is an increasing demand for high-precision, hi...

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Problems solved by technology

However, the element-free method no longer needs the connection information between nodes, and often uses nodes with arbitrary distribution. The dense background grid obtained by uniform subdivision is suitable for the local dense node distribution area, but it is very suitable for the sparsely distributed area. These areas are often areas with small field value changes, and only need to match the sparse background grid to achieve good calculation accuracy. The dense background grid distribution in these areas greatly increases the amount of calculation, and the simulation cost becomes multiplied, which limits the application of the element-free method in DC resistivity forward modeling

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