Dual Laterolog Tool and Its Electrode System, Formation Resistivity Measurement Method

A dual lateral logging, formation resistivity technology, applied in surveying, earthwork drilling, wellbore/well components, etc., can solve the problem of not solving the influence of vertical potential gradient, difficult to achieve measurement accuracy, etc., to shorten the tool The effect of length, improved longitudinal resolution, and improved measurement accuracy

Active Publication Date: 2021-09-03
CNPC GREATWALL DRILLING ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the high-resolution azimuthal resistivity logging tool and logging method adopt digital focus mode and hard focus mode, compared with the original hard focus The method of short-circuiting the electrode ring with the same name still does not solve the influence of the vertical potential gradient formed in the center of the instrument, making it difficult to achieve higher measurement accuracy

Method used

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  • Dual Laterolog Tool and Its Electrode System, Formation Resistivity Measurement Method
  • Dual Laterolog Tool and Its Electrode System, Formation Resistivity Measurement Method
  • Dual Laterolog Tool and Its Electrode System, Formation Resistivity Measurement Method

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Experimental program
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Effect test

Embodiment 1

[0060] figure 2 C is the deep laterolog mode synthesized by the high-resolution dual laterolog tool of the present invention. The formation apparent resistivity can be calculated by using the data collected in the above three working modes. as attached figure 2 As shown in C, using the combination of mode 1 and mode 3, the deep lateral apparent resistivity can be obtained:

[0061]

[0062] in, is the deep lateral instrument coefficient,

[0063]

[0064]

[0065]

[0066]

[0067] .

Embodiment 2

[0069] image 3 C is the shallow laterolog mode synthesized by the high-resolution dual laterolog tool of the present invention. The formation apparent resistivity can be calculated by using the data collected in the above three working modes. as attached image 3 As shown in C, the shallow lateral apparent resistivity can be obtained by using the combination of mode 2 and mode 3:

[0070]

[0071] in, is the shallow lateral instrument coefficient,

[0072]

[0073] .

[0074] Using the data collected in the above three working modes, the following high-resolution deep and shallow lateral apparent resistivity curves can also be calculated:

[0075]

[0076]

[0077] in, , are high-resolution deep and shallow lateral instrument coefficients, respectively,

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] .

[0085] In the present invention, electrodes A2 and A2' are short-circuited, electrodes A0 and A0' are short-circu...

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Abstract

The invention relates to a dual laterolog tool, its electrode system, and a method for measuring formation resistivity. The electrode system includes an electrode system and an insulating mandrel, which is composed of a plurality of electrodes arranged on one insulating mandrel, and is passed through The wire is connected to the measuring circuit, and the plurality of electrodes are separated by insulating materials. The center of the insulating mandrel is a metal rod, and a through hole is arranged in the center of the metal rod. The metal rod is insulated from the electrode system. The system includes: the main electrode A0, A0' arranged in the middle of the electrode system; at least one pair of shielding electrodes A2, A2' and A1, A1' emitting shielding current to focus the main current; multiple pairs of voltage measurement for measuring the electrode voltage Electrodes A1*, A1*' and M0, M0'; and at least one pair of voltage monitoring electrodes M2, M2' and M1, M1' for voltage monitoring, wherein the shielding electrodes A2, A2' are short-circuited, and the main electrodes A0, A0 'Short circuit, other electrodes are not short circuited. As a result, higher measurement accuracy is achieved compared with the hard focus method.

Description

technical field [0001] The invention relates to a well logging device used for petroleum exploration and development, in particular to a double lateral logging instrument, its electrode system, and a formation resistivity measurement method. Background technique [0002] Dual laterolog tool is the main instrument for measuring formation resistivity in open hole, studying formation invasion changes, and estimating oil saturation. The traditional dual laterolog tool mainly includes electrode system, electronic circuit, and insulating nipple. The resolution is about 0.6 meters. When the traditional dual laterolog tool performs deep lateral logging, the annular electrode emits current into the formation, and the cylindrical electrode emits shielding current to focus on the main current. A feedback loop is required in the electronic circuit to adjust the shielding current, and the control monitoring electrode is at Equipotential. For example, Chinese patent CN1712995A disclose...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B49/00E21B47/00
Inventor 胡海涛白庆杰肖占山张森峰高秀晓姚春明朱瑞明于振南邵琨
Owner CNPC GREATWALL DRILLING ENG
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