A combined 1-D/2-D inversion algorithm of cross-hole electromagnetic fields

作者：Wei BJ^*

来源：Chinese Journal of Geophysics, 2006, 49(1): 264-274.

• cross-hole
• electromagnetic fields
• combined inversion
• Green's function

A combined 1-D/2-D inversion algorithm is proposed for a 2-D cross-hole model with cylindrical symmetry. Based on the Green's function of longitudinal layered background medium, the algorithm can simultaneously invert the conductivities of the 1-D background and the 2-D anomalous sections by taking the result of the 1-D inversion as the initial model for the combined inversion. Since the coefficients of the Green's function are calculated through a recursion technique, the integral of the Green's function with respect to the space coordinates and the differential of the Green's function with respect to the background conductivities can be simultaneously obtained very conveniently, and thus the calculation of the Jacobian Matrix M becomes more quickly, conveniently and accurately. Inversion examples show the effectiveness of the algorithm. The examples also indicate that the reconstruction of the 1-D background conductivities converges more quickly than the reconstruction of the conductivities on the 2-D imaging section, and that the effect of precision of the measured data on the imaging of the 2-D section is greater than that on the distribution of the background conductivities.

• 出版日期2006-1
• 单位中国石油大学（北京）