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Time-domain signal processing method for through casing differential resistivity logging

A technology of differential resistance and time-domain signals, which can be used in measurement, earthwork drilling and production, wellbore/well components, etc., and can solve problems such as complex mechanical structures

Inactive Publication Date: 2018-04-20
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This complicates the mechanics of the instruments used

Method used

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  • Time-domain signal processing method for through casing differential resistivity logging
  • Time-domain signal processing method for through casing differential resistivity logging
  • Time-domain signal processing method for through casing differential resistivity logging

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Embodiment

[0040] The time-domain signal processing method of the casing differential resistivity logging of the present invention comprises the following steps:

[0041] one, figure 1 Shown is the actual logging interface of transient electromagnetic through casing, (a) is the matching natural gamma ray logging curve and magnetic positioning curve, which are used to determine the depth of the formation where the tool is located; (b) is real-time (at a certain The original logging waveforms of four different source distances measured by casing formation resistivity logging at time ) are constantly refreshed during the logging process. In each waveform diagram, there are four moments in which the waveform changes sharply, corresponding to the forward conduction, forward turn-off, reverse conduction and reverse turn-off moments of the excitation waveform of the transient electromagnetic logging transmitting coil. Because the coil current changes greatly at these four moments, the transien...

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Abstract

The invention discloses a time-domain signal processing method for through casing differential resistivity logging. The time-domain signal processing method comprises the steps that transient electromagnetic induction received waveforms at four moments of forward turn-on, forward turn-off, reverse turn-on and reverse turn-off are obtained; the transient electromagnetic induction received waveformsat the adjacent depth points subtract to obtain the responding difference waveform 1, the responding difference waveform 2 and the responding difference waveform 3; the responding difference at the coupling position is replaced through the responding difference at the adjacent depth points, so that the coupling influence is removed; the maximum values of the responding difference waveform 1, theresponding difference waveform 2 and the responding difference waveform 3 at the four moments are selected, and the maximum values are converted to stratum conductivity difference curves; the stratumconductivity difference curve at any moment in any responding difference waveform is selected and integrated to obtain a stratum conductivity curve of the measured well section; the same method is applied to other moments of the responding difference waveforms to generate the stratum conductivity curve of the corresponding well section; the time-domain signal processing method is applied to the four moments of the other two responding difference waveforms to generate the stratum conductivity curve of the corresponding well section; and all the stratum conductivity curves are weighted and added, and the reciprocal value is taken to obtain the stratum conductivity curve.

Description

technical field [0001] The invention belongs to the technical field of special instruments for measuring physical parameters of casing well formations and evaluating lithology in petroleum engineering well logging construction, and more specifically relates to a time-domain signal processing method for through-casing differential resistivity logging. Background technique [0002] In the process of oil development, formation resistivity measurement under cased well conditions is very important. The formation resistivity measured at different periods or the resistivity distribution information at different depths can be used to evaluate the distribution of remaining oil in the formation during the development process. Adjust the development plan to provide specific basis. The existing through-casing formation resistivity logging method adopts the direct current method, pushes the electrode to the inner wall of the casing, supplies power to the casing and the formation through ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B49/00E21B47/00
CPCE21B47/00E21B49/00
Inventor 沈建国舒敦利沈永进
Owner TIANJIN UNIV
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