Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool

When logging while drilling directional lateral instruments work in formations, due to the long length of the drill collar, the surface potential attenuation is severe. The current flowing out of the drill collar will produce axial components, which cannot flow out strictly perpendicular to the surf...

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Main Authors: TANG Zhanghong, YANG Zhiliang, CHEN Gang, ZHANG Guoyan, ZHAI Xingyu, SONG Sen
Format: Article
Language:zho
Published: Editorial Office of Well Logging Technology 2024-04-01
Series:Cejing jishu
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Online Access:https://www.cnpcwlt.com/#/digest?ArticleID=5576
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author TANG Zhanghong
YANG Zhiliang
CHEN Gang
ZHANG Guoyan
ZHAI Xingyu
SONG Sen
author_facet TANG Zhanghong
YANG Zhiliang
CHEN Gang
ZHANG Guoyan
ZHAI Xingyu
SONG Sen
author_sort TANG Zhanghong
collection DOAJ
description When logging while drilling directional lateral instruments work in formations, due to the long length of the drill collar, the surface potential attenuation is severe. The current flowing out of the drill collar will produce axial components, which cannot flow out strictly perpendicular to the surface of the drill collar, resulting in inaccurate measurement results. To address this issue, five soft focusing working modes are designed based on the electrode structure of the azimuth laterolog resistivity imaging logging tool (RIT), and expressions for calculating the azimuth lateral electrode current and apparent resistivity under different working modes are provided. The soft focusing working mode can simulate the simultaneous operation of symmetric antennas with different source distances to maintain the surface equipotential of the drill collar, and obtain more accurate axial current through linear superposition difference approximation. By using the three-dimensional finite element method to calculate the response of different soft focusing working modes in gradually changing thin interlayers, and comparing it with the original logging response. The results show that the soft focusing method can smooth out the peak and step phenomena at the interface of a single transmitting antenna, and is more accurate in identifying thin layers and calculating apparent resistivity. It has certain guiding significance for the interpretation of actual logging data of instruments.
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language zho
publishDate 2024-04-01
publisher Editorial Office of Well Logging Technology
record_format Article
series Cejing jishu
spelling doaj-art-2fec384b9d0345f09bc0f37f5402fa7d2025-08-20T03:08:18ZzhoEditorial Office of Well Logging TechnologyCejing jishu1004-13382024-04-0148213514110.16489/j.issn.1004-1338.2024.02.0011004-1338(2024)02-0135-07Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD ToolTANG Zhanghong0YANG Zhiliang1CHEN Gang2ZHANG Guoyan3ZHAI Xingyu4SONG Sen5School of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, ChinaLogging Technology Research Institute, China National Logging Corporation, Xi’an, Shaanxi 710077, ChinaLogging Technology Research Institute, China National Logging Corporation, Xi’an, Shaanxi 710077, ChinaLogging Technology Research Institute, China National Logging Corporation, Xi’an, Shaanxi 710077, ChinaLogging Technology Research Institute, China National Logging Corporation, Xi’an, Shaanxi 710077, ChinaLogging Technology Research Institute, China National Logging Corporation, Xi’an, Shaanxi 710077, ChinaWhen logging while drilling directional lateral instruments work in formations, due to the long length of the drill collar, the surface potential attenuation is severe. The current flowing out of the drill collar will produce axial components, which cannot flow out strictly perpendicular to the surface of the drill collar, resulting in inaccurate measurement results. To address this issue, five soft focusing working modes are designed based on the electrode structure of the azimuth laterolog resistivity imaging logging tool (RIT), and expressions for calculating the azimuth lateral electrode current and apparent resistivity under different working modes are provided. The soft focusing working mode can simulate the simultaneous operation of symmetric antennas with different source distances to maintain the surface equipotential of the drill collar, and obtain more accurate axial current through linear superposition difference approximation. By using the three-dimensional finite element method to calculate the response of different soft focusing working modes in gradually changing thin interlayers, and comparing it with the original logging response. The results show that the soft focusing method can smooth out the peak and step phenomena at the interface of a single transmitting antenna, and is more accurate in identifying thin layers and calculating apparent resistivity. It has certain guiding significance for the interpretation of actual logging data of instruments.https://www.cnpcwlt.com/#/digest?ArticleID=5576logging while drilling resistivity loggingazimuthal laterolog resistivitypotential decaysoft focusdetection characteristic
spellingShingle TANG Zhanghong
YANG Zhiliang
CHEN Gang
ZHANG Guoyan
ZHAI Xingyu
SONG Sen
Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
Cejing jishu
logging while drilling resistivity logging
azimuthal laterolog resistivity
potential decay
soft focus
detection characteristic
title Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
title_full Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
title_fullStr Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
title_full_unstemmed Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
title_short Simulation Analysis of Soft Focusing of Azimuth Laterolog Resistivity Imaging LWD Tool
title_sort simulation analysis of soft focusing of azimuth laterolog resistivity imaging lwd tool
topic logging while drilling resistivity logging
azimuthal laterolog resistivity
potential decay
soft focus
detection characteristic
url https://www.cnpcwlt.com/#/digest?ArticleID=5576
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AT chengang simulationanalysisofsoftfocusingofazimuthlaterologresistivityimaginglwdtool
AT zhangguoyan simulationanalysisofsoftfocusingofazimuthlaterologresistivityimaginglwdtool
AT zhaixingyu simulationanalysisofsoftfocusingofazimuthlaterologresistivityimaginglwdtool
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