Lamellate Layer Convergence Algorithm Based on the Magnetotelluric Equivalence Principle

The non-uniqueness problem of inversion is a large obstacle in improving geophysical interpretation resolution. At present, the main factors which affect the non-uniqueness of the solutions of magnetotelluric sounding are equivalence and volume effect. For example, true parameters of low resistance lamellate layer are difficult to determine by inversion because of the ‘s’ equivalence, and we usually get the biased thickness and resistivity that meets equivalence condition, which is clearly not consistent with the actual situation. In order to make the inversion results correspond to the actual situation better, the new assistant algorithm based on the Marquardt inversion and equivalence principle was designed in this paper, and we used ‘S’ and ‘H’ equivalence principle flexibly to make the thickness and resistivity converge to a result that is more close to the actual situation. This method provides a convenient means of combining magnetotelluric sounding data with logging and seismology data to make associated interpretation or inversion, so that thickness and resistivity of target can be determined effectively.