Deconvolution specific resistance treatment method of cased well

Abstract

The invention discloses a deconvolution specific resistance treatment method of a cased well. On the basis of the secondary field difference measured by two adjacent depth points, the relation betweenthe secondary field difference and the apparent conductivity difference and stratum conductivity sequence is derived, a stratum conductivity curve is reduced through the deconvolution method, and a stratum specific resistance curve is reduced in a reciprocal manner. The solving problem of the stratum conductivity curve is solved through difference deconvolution; and under the condition that longitudinal geometrical factor spacing is selected correctly, the stratum conductivity can be completely reduced, and the stratum resolution ratio is increased.

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 cased well deconvolution resistivity processing method. Background technique [0002] In oil exploration and development, well logging is a very important means to evaluate oil and gas reservoirs. In terms of logging technology, the transient electromagnetic through-casing logging technology is developed and improved on the basis of geophysical prospecting and induction logging. Usually, the transmitted signal is a step signal, and transient excitation is used to measure the difference in the cased hole. The transient response waveform of the source distance. The transmitted electromagnetic signal forms an eddy current in the casing and the medium outside the casing, and the secondary field generated by the eddy current passes through the casing again and is received by the rece...

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Problems solved by technology

[0003] The received signal also includes the direct coupling signal (i.e. the primary field) and the secondary field signal. The traditional method cannot eliminate the primary field irrelevant to the formation conductivity, so that the secondary field and apparent conductivity cannot be obtained, and the formation conductivity and Resistivity information

Subtraction of waveforms measured at adjacent depths at the same source distance can remove all useless signals in the response (primary field and secondary field responses of fluid, casing, and cement sheath in the well) to obtain formations measured at two adjacent depth points (area ) of the secondary field difference, the existing technology believes that the secondary field difference is directly proportional to the formation conductivity difference and inversely proportional to the formation resistivity difference, but it has not been found that the secondary field difference can also be described by the difference of geometric factors , and it is impossible to give an accurate calculation method for the formation resistivity

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