ANALYSIS OF RADIAL DETECTION CHARACTERISTICS OF MONOPOLE SONIC LOGGING
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- 英文论文题名：ANALYSIS OF RADIAL DETECTION CHARACTERISTICS OF MONOPOLE SONIC LOGGING
- 论文作者：Yi-han GENG ; Hao CHEN ; Xiao HE ; Xiu-mei ZHANG ; Xiu-ming WANG
- 英文论文作者：Yi-han GENG ; Hao CHEN ; Xiao HE ; Xiu-mei ZHANG ; Xiu-ming WANG ; University of Chinese Academy of Sciences ; State Key laboratory of Acoustics ; Institute of Acoustics ; Chinese Academy of Sciences
- 年：2016
- 作者机构：University of Chinese Academy of Sciences;State Key laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences;
- 英文论文关键词：Acoustic logging ; Radial detection depth ; Finite difference method ; Slowness-time correlation-method
- 会议召开时间：2016-10-21
- 会议录名称：2016年全国压电和声波理论及器件应用研讨会论文摘要集
- 英文会议录名称：Abstract Book of 2016 Symposium on Piezoelectricity, Acoustic Waves and Device Applications
- 语种：英文
- 分类号：P631.81
- 学会代码：AGLU
- 会议名称：2016年全国压电和声波理论及器件应用研讨会
- 会议地点：中国陕西西安
- 主办单位：中国力学学会、中国声学学会、IEEE UFFC分会
- 学会名称：中国力学学会
- 页数：2
- 文件大小：11k
- 原文格式：D
- 会议级别：全国
摘要
Background, Motivation and Objective Drilling causes variation of the rock properties in the vicinity of a wellbore. Usually, acoustic velocities, including P-and S-wave ones near the borehole wall are smaller than those of the virgin formation. In order to understand the velocity profile along the borehole radial direction for formation characterizations, we investigate the influence of the thickness of the transition zone on monopole longitudinal waves at varying source-to-receiver separations and frequency range based on the radial stepped sonic model. This research may be applied for radial tomography of longitudinal wave velocity with monopole logging tools. Statement of Contribution/Methods In this article, we use the radial cylindrical layered model to examine monopole logging response with a two-dimensional axisymmetric finite difference method. Three variables are set, and they are the transition zone thickness, the source frequency and source-to-receiver spacing, respectively. We also use the slowness-time correlation-method to evaluate sound speed variations under different conditions. At last, based on the ray theory, the variation characteristics of the arrival time of the first wave under different conditions are analyzed. Results For a certain source-to-receiver offset, there is a critical value for the intermediate layer thickness. When the intermediate layer thickness is less than that value, the first wave is the outermost layer formation compressional wave. When the intermediate layer thickness is greater than that value, the first wave is the compressional wave of the formation closest to the wellbore. The longitudinal waves sliding along different interfaces can be separated from each other in the time domain with the appropriate source to receiver offset. According to this result, one can possibly obtain different speeds of the intermediate layers. Meanwhile, the first wave amplitude is gradually weakened as the spacing increases. For sources with same amplitudes, the first waves of low-frequency are larger than those from high-frequency sources. Discussion and Conclusions The radial detection characteristics of longitudinal waves are greatly influenced by spacing. By combining different signals with various spacings, it is possible to obtain the tomography of the compressional wave velocities near wellbore. Since the simulation frequency range in this article is limited, the impact of frequency on the radial detection characteristics of longitudinal waves is not very obvious.
Background, Motivation and Objective Drilling causes variation of the rock properties in the vicinity of a wellbore. Usually, acoustic velocities, including P-and S-wave ones near the borehole wall are smaller than those of the virgin formation. In order to understand the velocity profile along the borehole radial direction for formation characterizations, we investigate the influence of the thickness of the transition zone on monopole longitudinal waves at varying source-to-receiver separations and frequency range based on the radial stepped sonic model. This research may be applied for radial tomography of longitudinal wave velocity with monopole logging tools. Statement of Contribution/Methods In this article, we use the radial cylindrical layered model to examine monopole logging response with a two-dimensional axisymmetric finite difference method. Three variables are set, and they are the transition zone thickness, the source frequency and source-to-receiver spacing, respectively. We also use the slowness-time correlation-method to evaluate sound speed variations under different conditions. At last, based on the ray theory, the variation characteristics of the arrival time of the first wave under different conditions are analyzed. Results For a certain source-to-receiver offset, there is a critical value for the intermediate layer thickness. When the intermediate layer thickness is less than that value, the first wave is the outermost layer formation compressional wave. When the intermediate layer thickness is greater than that value, the first wave is the compressional wave of the formation closest to the wellbore. The longitudinal waves sliding along different interfaces can be separated from each other in the time domain with the appropriate source to receiver offset. According to this result, one can possibly obtain different speeds of the intermediate layers. Meanwhile, the first wave amplitude is gradually weakened as the spacing increases. For sources with same amplitudes, the first waves of low-frequency are larger than those from high-frequency sources. Discussion and Conclusions The radial detection characteristics of longitudinal waves are greatly influenced by spacing. By combining different signals with various spacings, it is possible to obtain the tomography of the compressional wave velocities near wellbore. Since the simulation frequency range in this article is limited, the impact of frequency on the radial detection characteristics of longitudinal waves is not very obvious.
Background, Motivation and Objective Drilling causes variation of the rock properties in the vicinity of a wellbore. Usually, acoustic velocities, including P-and S-wave ones near the borehole wall are smaller than those of the virgin formation. In order to understand the velocity profile along the borehole radial direction for formation characterizations, we investigate the influence of the thickness of the transition zone on monopole longitudinal waves at varying source-to-receiver separations and frequency range based on the radial stepped sonic model. This research may be applied for radial tomography of longitudinal wave velocity with monopole logging tools. Statement of Contribution/Methods In this article, we use the radial cylindrical layered model to examine monopole logging response with a two-dimensional axisymmetric finite difference method. Three variables are set, and they are the transition zone thickness, the source frequency and source-to-receiver spacing, respectively. We also use the slowness-time correlation-method to evaluate sound speed variations under different conditions. At last, based on the ray theory, the variation characteristics of the arrival time of the first wave under different conditions are analyzed. Results For a certain source-to-receiver offset, there is a critical value for the intermediate layer thickness. When the intermediate layer thickness is less than that value, the first wave is the outermost layer formation compressional wave. When the intermediate layer thickness is greater than that value, the first wave is the compressional wave of the formation closest to the wellbore. The longitudinal waves sliding along different interfaces can be separated from each other in the time domain with the appropriate source to receiver offset. According to this result, one can possibly obtain different speeds of the intermediate layers. Meanwhile, the first wave amplitude is gradually weakened as the spacing increases. For sources with same amplitudes, the first waves of low-frequency are larger than those from high-frequency sources. Discussion and Conclusions The radial detection characteristics of longitudinal waves are greatly influenced by spacing. By combining different signals with various spacings, it is possible to obtain the tomography of the compressional wave velocities near wellbore. Since the simulation frequency range in this article is limited, the impact of frequency on the radial detection characteristics of longitudinal waves is not very obvious.
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