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Method for determining nature of wellbore in geological layer

A technology for geological layers and wellbore, which is applied in earth-moving drilling, wellbore/well components, measurement, etc., can solve the problems of affecting the sound wave performance, reducing the accuracy of cement evaluation, etc., and achieve the effect of improving accuracy and high accuracy

Inactive Publication Date: 2020-06-26
XI'AN PETROLEUM UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these traditional methods are more suitable for thinner casings (e.g., thinner than 12mm casing), but not for the acoustic attenuation of larger and thicker casings in drilling muds more commonly used today, because This wellbore environment can affect acoustic performance, reducing the accuracy of cement evaluation

Method used

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  • Method for determining nature of wellbore in geological layer
  • Method for determining nature of wellbore in geological layer
  • Method for determining nature of wellbore in geological layer

Examples

Experimental program
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comparative example 1

[0044] In a drilling operation, a wellbore 3 is drilled, and an annular packing material 4 is used to seal the annulus 5 , ie the space between the wellbore 3 , casing 6 and casing collar 7 , through cementing operations.

[0045] Such as figure 1 As shown, the casing 6 represents the length of the casing string connected together by the casing collar 7 to form a stable wellbore. The casing 6 and the casing collar 7 can be made of carbon steel, stainless steel or other suitable materials to Withstand various pressures, such as collapse, burst and tensile failure, and chemical fluid erosion. Surface equipment 1 can perform various logging operations to detect the condition of the wellbore 3; logging operations can measure parameters of the geological formation 2 (such as resistivity or porosity) and the wellbore 3 (such as temperature, pressure, fluid type or fluid flow rate) The sonic logging tool 9 can provide sonic cement evaluation and wellbore integrity data (such as casi...

Embodiment 1

[0058] refer to Figure 5 , a method of determining properties of a wellbore in a geological formation, comprising the steps of:

[0059] (1) Obtaining acoustic wave data: Acquiring acoustic wave data from the acoustic logging tool, that is, inputting the acoustic wave waveform data composed of one or more reflected sound waves from the acoustic logging tool deployed in the wellbore of the casing; the acoustic wave data here refers to casing thickness.

[0060] (2) Standardized acoustic waveform: normalize the acoustic waveform data with a normalized workflow to obtain a normalized waveform; the normalized workflow can be found in Figure 6and Figure 7 , transform the acoustic waveform data 34 from the time domain to the frequency domain using Fourier transform, thereby producing a spectrum 37; the spectrum 37 can be used to estimate the specular spectrum 38 (the specular spectrum 38 can be a waveform generated based on prior knowledge, its shape is similar to The wave spe...

Embodiment 2

[0067] A method of determining properties of a wellbore in a geological formation comprising the steps of:

[0068] (1) Obtaining acoustic wave data: Acquiring acoustic wave data from acoustic logging tools, that is, inputting acoustic wave data composed of one or more reflected sound waves from acoustic logging tools deployed in wellbores with mud, casing and annular filling materials ; The acoustic waveform data here is the resonance tail similar to the exponential decay generated by the reverberation in the casing. The resonance tail has different responses and sensitivities to the acoustic impedance changes of the mud and the annular filling, respectively expressed as the annular filling material The acoustic impedance Za of the mud and the acoustic impedance Zm of the mud;

[0069] (2) Standardize the sound wave waveform: standardize the obtained sound wave waveform data with a normalized workflow to obtain a normalized wave form 35 .

[0070] (3) Workflow inversion proc...

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Abstract

The invention provides a method for determining the nature of a wellbore in a geological layer. The method comprises the following steps of obtaining acoustic waveform data, standardizing an acousticwaveform, conducting reversal processing for workflow, and outputting parameters. The method has the beneficial effects that the method for determining the nature of the wellbore in the geological layer is suitable for acoustic attenuation of larger and thicker casing pipes in more commonly used drilling slurry at present; the acoustic wave performance is not affected by the wellbore environment,and the accuracy of evaluation is improved; and accurate data such as casing pipe thickness, acoustic impedance of annular filling materials and acoustic impedance of slurry can be determined and output.

Description

technical field [0001] The invention belongs to the technical field of wellbore operations, and relates to a technique for determining characteristics of underground formations by using acoustic wellbore data, and in particular to a method for determining the properties of wellbores in geological formations by using resonance inversion of the acoustic impedance of an annular space behind a casing. Background technique [0002] Shafts refer to the passages excavated to connect the ground and underground roadways when mining, building long tunnels and underground railways. When the well is completed, the casing or pipe string is usually set in the wellbore, and the annular space filling material (such as cement) is set in the annular space between the casing and the formation. One of the purposes is to separate the oil-producing layer and the gas-producing layer from each other. , and separate it from the water-bearing formation. If cement does not provide isolation of one ar...

Claims

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Application Information

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IPC IPC(8): E21B49/00E21B47/16E21B47/18
CPCE21B49/00E21B47/16E21B47/18
Inventor 杜霄周静
Owner XI'AN PETROLEUM UNIVERSITY