Transient electromagnetic rapid statistical inversion method

Abstract

The invention discloses a transient electromagnetic rapid statistical inversion method, and belongs to the technical field of geophysical signal processing and analysis, and the method comprises the steps: collecting transient electromagnetic data of an exploration region; establishing an inversion model of rapid statistical inversion, setting a model dimension change range of the inversion model to be (1-kN0) and an iteration convergence condition of the inversion, and when the iteration convergence condition of the inversion is met, data fitting variance and model dimension change in the iteration process of a single Markov chain are stable enough; and performing rapid statistical inversion on the acquired transient electromagnetic data according to the inversion model, and when an iteration convergence condition of the inversion is reached, obtaining a posterior probability density function estimation result of the formation resistivity and the formation depth, thereby completing the rapid statistical inversion. The transient electromagnetic statistical inversion method is subjected to efficiency optimization, the engineering practicability of the algorithm is improved, and the method has important significance in promoting application of transient electromagnetism in urban underground space and tunnel engineering exploration.

Description

technical field [0001] The invention relates to the technical field of geophysical signal processing and analysis, in particular to a transient electromagnetic fast statistical inversion method. 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 related geological problems. Inversion of subsurface resistivity by induced secondary transient magnetic field is one of the most important steps in transient electromagnetic exploration. [0003] The inversion of transient electromagnetic method ...

AI Technical Summary

Problems solved by technology

However, limited by the huge amount of calculation and the forward modeling speed of TEM itself, the calculation efficiency of this method is slow. Even if the conventional statistical inversion algorithm only performs the inversion of a single TEM data, it can be performed on an ordinary computer (such as computer configuration For Intel(R) Core(TM) I7-8700k, memory 32G), the calculation time usually takes more than 7 hours (1 million iterations), it is difficult to realize engineering practicality

Images