Method for extracting sleeve wave attenuation rate through dispersion correction

A technology of dispersion correction and casing wave, which is applied in seismology, earthwork drilling, measurement, etc. for well logging records. It can solve the error of attenuation rate and true attenuation rate, and does not consider the dispersion effect of sound waves along the casing. and other issues to achieve the effect of reducing errors

Inactive Publication Date: 2013-08-14
CHINA UNIV OF PETROLEUM (EAST CHINA)
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Problems solved by technology

[0003] The attenuation rate results calculated by the sector cement cement logging tool exclude the influence of the emission intensity of the acoustic wave transmitting transducer and the sensitivity of the acoustic wave receiving transducer, but there is a large error between the calculated attenuation rate and the real attenuation rate, which causes this The reason for this error is that the above processing method does not consider the dispersion effect in the process of sound wave propagating along the casing

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  • Method for extracting sleeve wave attenuation rate through dispersion correction
  • Method for extracting sleeve wave attenuation rate through dispersion correction
  • Method for extracting sleeve wave attenuation rate through dispersion correction

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Embodiment Construction

[0033] Such as figure 1 As shown, the method of extracting casing wave attenuation rate by using dispersion correction includes the following steps:

[0034] Step 1. Calculation of casing wave theoretical dispersion curve

[0035] (1) Establish a cased well model based on mud, casing, cement and formation parameters

[0036] According to the acoustic parameters and thickness of the mud, casing, cement and formation medium of the production well, the cased well model of the layered medium of the plane interface is established, such as figure 2 As shown, r is the borehole radius, d is the casing thickness, and h is the cement thickness.

[0037] (2) Using the Newton-Raphson iterative method to calculate the theoretical casing wave dispersion curve of the cased well model with layered media on the plane interface

[0038] The displacement potential function (1) is established, and the dispersion equation (3) of the cased hole is obtained by solving the acoustic boundary condi...

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Abstract

The invention belongs to the field of applied geophysical well logging and particularly relates to a method for extracting sleeve wave attenuation rate through dispersion correction. The method includes the following steps: 1 calculating a sleeve wave theory dispersion curve; 2 conducting sector cement bond well logging on measuring points and obtaining waveform data corresponding to each sector; 3 conducting dispersion correction on the waveform data transmitted and received by sound wave; 4 extracting waveform attenuation rate after dispersion correction; and 5 repeating step 2, step 3 and step 4 and obtaining attenuation rate of each sector of the measuring points. The method has the advantage of being capable of eliminating effects of dispersion effect in a sleeve on waveform amplitude, obtaining real attenuation rate corresponding to a gluing condition of the sleeve and the cement sheath and greatly reducing attenuation rate calculation errors.

Description

technical field [0001] The invention belongs to the field of applied geophysical well logging, and in particular relates to a method for extracting the attenuation rate of the casing wave; it is used to eliminate the influence of the dispersion effect in the casing on the waveform amplitude, and accurately obtain the results of the cemented state of the casing and the cement sheath. corresponding decay rate. Background technique [0002] In terms of cementing quality evaluation, the sector cement bond logging tool (SBT, Segmented Bond Tool) measurement system quantitatively measures the cement bond in 6 angle blocks including the entire wellbore in a surrounding manner. The core component is composed of six slides, each of which is equipped with a sound wave transmitting transducer (T) and a sound wave receiving transducer (R), which together form a double-transmitting and double-receiving compensation of six sectors helically arranged Type casing wave attenuation measureme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B47/005E21B47/14G01V1/40
Inventor 陈雪莲唐晓明董兴蒙
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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