Abstract:

The study of efficient inversion method was carried out for continuous formation, targeting at improving the inversion precision and efficiency of 3-dimensional (3D) induced polarization (IP) data with waved geometry. Blocky continuously varied parameterization based on tetrahedral element was developed for the continuous changed resistivity model with fluctuated geometry. The stability and resolution of inversion was improved by including model smoothness and background prior information. The inversion efficiency was achieved via decreasing the dimension of inverse problem, memory compression of the matrix of linear equations, and calculation of sensitivity matrix with a combination of reciprocal theory and quasi-Newton method. Finally, the effectiveness of the inversion method was tested by two examples. The numerical results show that the inversion converges within 6 iterations and takes very little computational time. The inversion result can give a good interpretation of the anomalous targets. The inversion software developed can be used to interpret the real data.

Key words: geophysical prospecting, complex geometry, 3D induced polarization data, continuous model, efficient inversion, sensitivity matrix