Magnetotelluric meshless numerical simulation method for random conductive medium model

Abstract

The present invention proposes a magnetotelluric meshless numerical simulation method for a random conductive medium model. The method is for heterogeneity of underground space, and according to the method, a shape function is constructed based on discrete nodes, and dependence on a mesh no longer exists. The method provided by the present invention comprises: using the spectral decomposition theory and the hybrid autocorrelation function theory of the stochastic modeling process to construct a random conductive medium model of underground space; establishing a function of the magnetotelluric corresponding boundary value problem; establishing a shape function of a meshless method by using a least squares method; using the Lagrange multipliers method to load essential boundary conditions; resolving linear equations by using the biconjugate gradient stabilized (BICGSTAB) algorithm of incomplete LU decomposition preprocessing, to obtain a field value of each node in the region; and using the field values to calculate the apparent resistivity and phase of each point, thereby completing the whole numerical simulation calculation process. The section calculated according to values of the random conductive medium model better complies with the actual situation, and is more advantageous for the interpretation and processing work of the magnetotelluric data.

Description

technical field [0001] The invention relates to a numerical simulation method of the magnetotelluric method in the field of geophysical exploration, which breaks away from the dependence on the grid in the traditional method in the calculation process, and is suitable for complex models such as random conductive medium models. Background technique [0002] Magnetotelluric Sounding, referred to as MT, is a geophysical prospecting method proposed by Soviet scholar Tikkonov (1950) and French scholar Cagniard (1953) in the early 1950s, using natural alternating electromagnetic fields to study the earth's electrical structure. . Because it does not need artificial power supply, is convenient to work, is not shielded by high-resistance layers, has a large exploration depth and low exploration cost, it is widely used. [0003] When building a model for research, the underground medium is usually regarded as a homogeneous or layered medium, but in actual geophysical exploration, th...

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Problems solved by technology

These methods are all based on grids. In the process of calculation and implementation, there are disadvantages such as high cost of generating grids, low precision in places where field values ​​change drastically, and difficulty in adaptive analysis.

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