Upper continuation and lower continuation method for multilayer equivalent source of magnetic survey data

Abstract

The invention provides an upper continuation and lower continuation method for a multilayer equivalent source of magnetic survey data. The method comprises the steps of S1, inputting magnetic field data, and establishing a topographic relief curved surface according to topographic height information of an area where a relief observation curved surface is located; S2, determining a spatial range ofmesh generation, performing continuous structured non-uniform mesh generation, and further determining an inversion model solving space; S3, according to the magnetic inclination angle, the magneticdeclination angle and the magnetic induction intensity of the geomagnetic field, performing integral equation three-dimensional inversion calculation with a depth regularization factor, a positive value constraint term and a regularization term on the magnetic field data based on an inversion model solving space to obtain a multi-layer equivalent source model of a magnetic anomalous body; and S4,performing magnetic field forward modeling calculation based on an integral equation by utilizing the multilayer equivalent source model to obtain magnetic field data after upper continuation and / or lower continuation generated by the magnetic anomalous body. The method has the beneficial effects that the required upper continuation or lower continuation data can be adaptively, quickly, efficiently and accurately generated for the magnetic anomalous body.

Description

technical field [0001] The invention relates to the technical field of geomagnetic surveying, in particular to a method for upward continuation and downward continuation of multi-layer equivalent sources of magnetic survey data. Background technique [0002] When geophysical magnetic methods (such as aeromagnetic survey and ground magnetic survey) are used for detection, the measurements are distributed on the surface of the undulating observation surface. Since the distance between the measurement position and the magnetic anomalous body is different, the main anomaly information reflected by the magnetic survey data also varies. difference. In practical applications, it is necessary to convert the measurement position of the data to meet the interpretation requirements of magnetic data processing. That is to extend the data on the observation surface to a higher observation surface to eliminate the influence of anomalous bodies closer to the observation surface on the mag...

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Problems solved by technology

[0005] However, these techniques have the following problems: 1) The number of equivalent source layers constructed by the above method is less than or equal to three layers, and the grid division is discontinuous; 2) The depth position of each equivalent source needs to be estimated separately, and then Placement; 3) The traditional continuation method has limitations on the continuation distance of data (generally less than 6 times the data point distance), and the calculation accuracy of continuation greater than the limit distance is poor

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