Resistivity processing method based on geometrical factor of cased well

Abstract

The invention provides a resistivity processing method based on the geometrical factor of a cased well. A reception waveform difference is obtained by conducting subtraction on waveforms measured at adjacent depths at the same source distance, a secondary field difference of measured formations (areas) at two adjacent depth points is obtained, an apparent conductivity difference is further obtained, and deconvolution is conducted on the apparent conductivity difference and a vertical differential geometrical factor difference; the shape of the geometrical factor difference of the cased well isput forward for the first time, the appropriate geometrical factor difference is found from the waveform difference, reception waveforms at four different source distances (0.275 m, 0.43 m, 0.6 m and0.77 m) are utilized to complete restoration of a formation conductivity curve, and the obtained formation conductivity curve is compared and verified with a real formation conductivity curve; and byobtaining reciprocals of the formation conductivities obtained after the first step, the second step, the third step, the fourth step and the fifth step are executed, the formation resistivity curveis obtained, and then distribution of remaining oil can be evaluated.

Description

technical field [0001] The invention belongs to the technical field of cased well formation physical parameter measurement in petroleum engineering well logging construction, and mainly relates to a resistivity processing method based on cased well geometric factors. Background technique [0002] In petroleum development, well logging is a very important means to evaluate oil and gas reservoirs. In terms of logging technology, formation resistivity measurement under transient electromagnetic cased well conditions is very important and effective, and resistivity distribution information at different depths can be used to evaluate the distribution of remaining oil during oil development. Usually the transmission signal is a step signal, and transient excitation is used to measure the transient response waveforms of different source distances in the cased hole. The transmitted electromagnetic signal forms an eddy current in the casing and the medium outside the casing, and the...

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Problems solved by technology

However, there are obvious differences between the geometric factors of cased wells and open hole wells. Experiments have proved that if the selection of geometric factors cannot guarantee the accuracy, the final result will inevitably be far from the real formation conductivity curve, and it is impossible to judge the formation quality. law, and it is impossible to give an accurate calculation method for formation resistivity

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