A method and device for inversion of transient electromagnetic resistivity

Abstract

The embodiment of the invention provides an inversion method of a transient electromagnetic resistivity. The method is characterized in that the method comprises: (1), an initial inversion model is set, inversion is carried out on the initial inversion model, and a corrected inversion model is obtained (2), layer number refining, inversion, and correction are carried out on the corrected inversion model; (3), the step (2) is repeated until the number of times of the layer number refining of the corrected inversion model reaches a preset value or the fitting error of the corrected inversion model response and the observation data is less than a first threshold value. According to the embodiment of the invention, the method has the following beneficial effects: refining is carried out on the inversion model gradually, so that the dependency on the initial model by the inversion process is reduced and the convergence of the inversion process is improved. Moreover, the number of times of iterations is reduced to the certain extent and the inversion speed is accelerated.

Description

technical field [0001] The invention belongs to the technical field of geophysical exploration, in particular to an inversion method of transient electromagnetic resistivity. Background technique [0002] The transient electromagnetic method uses an ungrounded return line or a grounded electrode to send a pulsed electromagnetic field underground. Under the excitation of a pulsed magnetic field, the underground conductive geological body is induced to generate eddy currents. An induced secondary transient magnetic field is formed. By observing the change law of the induced secondary transient magnetic field with time, the electrical characteristics (mainly resistivity) of the earth can be studied, so as to solve relevant geological problems. Inversion of subsurface resistivity by induced secondary transient magnetic field is one of the most important steps in transient electromagnetic exploration. [0003] In the prior art, the inversion process of the transient electromagn...

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Problems solved by technology

[0004] In the process of implementing this application, the inventor found at least the following problems in the prior art: the convergence of iterative calculation is the key to resistivity inversion. In the prior art, during the iterative calculation, the number of layers of the model and the The thickness is always the same as that of the initial model, so the subsequent inversion process is highly dependent on the initial model. In other words, the quality of the initial model determines the accuracy of the inversion results to a certain extent

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