基于分组互相关成像条件的微震逆时成像定位方法
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摘要
地面微地震记录的信噪比常常很低,微地震走时拾取困难,难以利用基于微震走时的方法进行震源定位,微震逆时成像作为有潜力的地面微震定位方法而成为研究热点.微震逆时成像的效果和效率与所使用的成像条件密切相关.本文通过对不同信噪比微地震记录的逆时成像实验,在分析现有的自相关和互相关成像条件优缺点的基础上,提出分组互相关成像条件,讨论了分组方式对成像结果的影响.结果表明:分组互相关成像兼顾了自相关和互相关成像的优势,避免了它们的缺点.通过采用合适的分组方式,可以在满足计算效率要求的情况下,获得空间分辨率很高的震源成像结果.分组互相关成像对低信噪比资料具有很强的适应性,是一种很有前景的地面微震定位方法.
Surface microseismic data often has a very low Signal-to-Noise Ratio(SNR). It is difficult to pick up the traveltime of microseismic events from the surface microseismic data. Then the traveltime-based methods cannot be used to locate the source at this situation. So the microseismic reverse-time image as a potential method for surface microseismic location has been paid attention to. The accuracy and efficiency of microseismic reserve-time imaging are closely related to the imaging conditions. In this paper, we analyze the advantages and disadvantages of the existing autocorrelation and crosscorrelation imaging conditions through the numerical experiments on microseismic reverse-time imaging from data with different SNR, and then propose the grouping crosscorrelation imaging condition. We also discuss the influence of the grouping on the imaging. The results show that the grouping crosscorrelation imaging has the advantages of both autocorrelation and crosscorrelation imagings, and avoids their shortcomings. By using the appropriate receiver grouping, the grouping crosscorrelation imaging can image the source with high spatial resolution and appropriate computational time. It has a strong adaptability to low SNR data, and is a promising method for surface microseismic location.
Surface microseismic data often has a very low Signal-to-Noise Ratio(SNR). It is difficult to pick up the traveltime of microseismic events from the surface microseismic data. Then the traveltime-based methods cannot be used to locate the source at this situation. So the microseismic reverse-time image as a potential method for surface microseismic location has been paid attention to. The accuracy and efficiency of microseismic reserve-time imaging are closely related to the imaging conditions. In this paper, we analyze the advantages and disadvantages of the existing autocorrelation and crosscorrelation imaging conditions through the numerical experiments on microseismic reverse-time imaging from data with different SNR, and then propose the grouping crosscorrelation imaging condition. We also discuss the influence of the grouping on the imaging. The results show that the grouping crosscorrelation imaging has the advantages of both autocorrelation and crosscorrelation imagings, and avoids their shortcomings. By using the appropriate receiver grouping, the grouping crosscorrelation imaging can image the source with high spatial resolution and appropriate computational time. It has a strong adaptability to low SNR data, and is a promising method for surface microseismic location.
引文
Artman B,Podladtchikov I,Witten B. 2010. Source location using time-reverse imaging [J]. Geophysical Prospecting,58(5): 861-873.
Claerbout J F. 1971. Toward a unified theory of reflector mapping [J]. Geophysics,36(3): 467- 481.
Dong S T,Gao H X. 2004. Microseismic monitering technology and its application to oilfield development [J]. P.I. (in Chinese),18(5): 5-8.董世泰,高红霞. 2004. 微地震监测技术及其在油田开发中的应用[J]. 石油仪器,18(5): 5-8.
Douma J,Snieder R. 2015. Focusing of elastic waves for microseismic imaging [J]. Geophysical Journal International,200(1): 390- 401.
Gajewski D,Tessmer E. 2005. Reverse modelling for seismic event characterization [J]. Geophysical Journal International,163(1): 276-284.
He Y,Zhang J Z,Li T Y. 2016. Improved source-scanning algorithm for microseismic location [J]. China Sciencepaper (in Chinese),11(21): 2450-2455.何勇,张建中,李同宇. 2016. 改进的震源扫描定位方法[J]. 中国科技论文,11(21): 2450-2455.
Kao H,Shan S J. 2004. The Source-Scanning Algorithm: mapping the distribution of seismic sources in time and space [J]. Geophysical Journal International,157(2): 589-594.
Larmat C S,Guyer R A,Johnson P A. 2009. Tremor source location using time reversal: Selecting the appropriate imaging field [J]. Geophysical Research Letters,36(22): 355-355.
Larmat C S,Guyer R A,Johnson P A. 2010. Time-reversal methods in geophysics [J]. Physics Today,63(8): 31-35.
Li L,Chen H,Wang X M. 2015. Weighted-elastic-wave interferometric imaging of microseismic source location [J]. Applied Geophysics,12(2): 221-234.
Li Z C,Sheng G Q,Wang W B,et al. 2014. Time-reverse microseismic hypocenter location with interferometric imaging condition based on surface and downhole multi-components [J]. OGP (in Chinese),49(4): 661- 666,671.李振春,盛冠群,王维波,等. 2014. 井地联合观测多分量微地震逆时干涉定位[J]. 石油地球物理勘探,49(4): 661- 666,671.
Liu H,Zhang J Z. 2014. STA/LTA algorithm analysis and improvement of Microseismic signal automatic detection [J]. Progress in Geophysics (in Chinese),29(4): 1708-1714,doi: 10.6038/pg20140429.刘晗,张建中. 2014. 微震信号自动检测的STA/LTA算法及其改进分析[J]. 地球物理学进展,29(4): 1708-1714,doi: 10.6038/pg20140429.
Liu H,Zhang J Z,Huang Z L. 2015. Microseismic event detection based on synchrosqueezing wavelet transform [J]. China Sciencepaper (in Chinese),10(21): 2472-2476.刘晗,张建中,黄忠来. 2015. 利用同步挤压变换检测微地震信号[J]. 中国科技论文,10(21): 2472-2476.
Liu Z W,Sa L M,Wu F R,et al. 2013. Microseismic monitor technology status for unconventional resource E&P and its future development in CNPC [J]. OGP (in Chinese),48(5): 843-853.刘振武,撒利明,巫芙蓉,等. 2013. 中国石油集团非常规油气微地震监测技术现状及发展方向[J]. 石油地球物理勘探,48(5): 843-853.
Lü H. 2012. Research on the seismic phase identification and the source location based on oilfield fracture microseismic monitoring [Ph.D. thesis]. Changchun: Jilin University.吕昊. 2012. 基于油田压裂微地震监测的震相识别与震源定位方法研究[博士论文]. 长春: 吉林大学.
Nakata N,Beroza G C. 2016. Reverse time migration for microseismic sources using the geometric mean as an imaging condition [J]. Geophysics,81(2): KS51-KS60.
Sava P. 2011. Micro-earthquake monitoring with sparsely sampled data [J]. Journal of Petroleum Exploration & Production Technology,1(1): 43- 49.
Wang C L,Cheng J B,Yin C,et al. 2013. Microseismic events location of surface and borehole observation with reverse-time focusing using interferometry technique [J]. Chinese J. Geophys (in Chinese),56(9): 3184-3196,doi: 10.6038/cjg20130931.王晨龙,程玖兵,尹陈,等. 2013. 地面与井中观测条件下的微地震干涉逆时定位算法[J]. 地球物理学报,56(9):3184-3196,doi: 10.6038/cjg20130931.
Xu J P. 2011. Research of crack monitoring and its application [J]. Science Technology and Engineering (in Chinese),11(11): 2575-2577.徐剑平. 2011. 裂缝监测方法研究及应用实例[J]. 科学技术与工程,11(11): 2575-2577.
Zhang J Z,Liu H,Zou ZH,et al. 2015. Velocity modeling and inversion techniques for locating microseismic events in unconventional reservoirs [J]. Journal of Earth Science,26(4): 495-501.
Zhang S,Liu Q L,Zhao Q,et al. 2002. Application of microseismic monitoring technology in development of oil field [J]. GPP (in Chinese),41(2): 226-231.张山,刘清林,赵群,等. 2002. 微地震监测技术在油田开发中的应用[J]. 石油物探,41(2): 226-231.
Zou Z H,Zhou H W,Bian A,et al. 2015. An Evaluation of Reverse-Time Imaging of Clustering Earthquakes [J]. Journal of Earth Science,26(4): 548-555.
Zou Z H,Zhou H W,Gurrola H. 2014. Reverse-time imaging of a doublet of microearthquakes in the Three Gorges Reservoir region [J]. Geophysical Journal International,196(3): 1858-1868.
Claerbout J F. 1971. Toward a unified theory of reflector mapping [J]. Geophysics,36(3): 467- 481.
Dong S T,Gao H X. 2004. Microseismic monitering technology and its application to oilfield development [J]. P.I. (in Chinese),18(5): 5-8.董世泰,高红霞. 2004. 微地震监测技术及其在油田开发中的应用[J]. 石油仪器,18(5): 5-8.
Douma J,Snieder R. 2015. Focusing of elastic waves for microseismic imaging [J]. Geophysical Journal International,200(1): 390- 401.
Gajewski D,Tessmer E. 2005. Reverse modelling for seismic event characterization [J]. Geophysical Journal International,163(1): 276-284.
He Y,Zhang J Z,Li T Y. 2016. Improved source-scanning algorithm for microseismic location [J]. China Sciencepaper (in Chinese),11(21): 2450-2455.何勇,张建中,李同宇. 2016. 改进的震源扫描定位方法[J]. 中国科技论文,11(21): 2450-2455.
Kao H,Shan S J. 2004. The Source-Scanning Algorithm: mapping the distribution of seismic sources in time and space [J]. Geophysical Journal International,157(2): 589-594.
Larmat C S,Guyer R A,Johnson P A. 2009. Tremor source location using time reversal: Selecting the appropriate imaging field [J]. Geophysical Research Letters,36(22): 355-355.
Larmat C S,Guyer R A,Johnson P A. 2010. Time-reversal methods in geophysics [J]. Physics Today,63(8): 31-35.
Li L,Chen H,Wang X M. 2015. Weighted-elastic-wave interferometric imaging of microseismic source location [J]. Applied Geophysics,12(2): 221-234.
Li Z C,Sheng G Q,Wang W B,et al. 2014. Time-reverse microseismic hypocenter location with interferometric imaging condition based on surface and downhole multi-components [J]. OGP (in Chinese),49(4): 661- 666,671.李振春,盛冠群,王维波,等. 2014. 井地联合观测多分量微地震逆时干涉定位[J]. 石油地球物理勘探,49(4): 661- 666,671.
Liu H,Zhang J Z. 2014. STA/LTA algorithm analysis and improvement of Microseismic signal automatic detection [J]. Progress in Geophysics (in Chinese),29(4): 1708-1714,doi: 10.6038/pg20140429.刘晗,张建中. 2014. 微震信号自动检测的STA/LTA算法及其改进分析[J]. 地球物理学进展,29(4): 1708-1714,doi: 10.6038/pg20140429.
Liu H,Zhang J Z,Huang Z L. 2015. Microseismic event detection based on synchrosqueezing wavelet transform [J]. China Sciencepaper (in Chinese),10(21): 2472-2476.刘晗,张建中,黄忠来. 2015. 利用同步挤压变换检测微地震信号[J]. 中国科技论文,10(21): 2472-2476.
Liu Z W,Sa L M,Wu F R,et al. 2013. Microseismic monitor technology status for unconventional resource E&P and its future development in CNPC [J]. OGP (in Chinese),48(5): 843-853.刘振武,撒利明,巫芙蓉,等. 2013. 中国石油集团非常规油气微地震监测技术现状及发展方向[J]. 石油地球物理勘探,48(5): 843-853.
Lü H. 2012. Research on the seismic phase identification and the source location based on oilfield fracture microseismic monitoring [Ph.D. thesis]. Changchun: Jilin University.吕昊. 2012. 基于油田压裂微地震监测的震相识别与震源定位方法研究[博士论文]. 长春: 吉林大学.
Nakata N,Beroza G C. 2016. Reverse time migration for microseismic sources using the geometric mean as an imaging condition [J]. Geophysics,81(2): KS51-KS60.
Sava P. 2011. Micro-earthquake monitoring with sparsely sampled data [J]. Journal of Petroleum Exploration & Production Technology,1(1): 43- 49.
Wang C L,Cheng J B,Yin C,et al. 2013. Microseismic events location of surface and borehole observation with reverse-time focusing using interferometry technique [J]. Chinese J. Geophys (in Chinese),56(9): 3184-3196,doi: 10.6038/cjg20130931.王晨龙,程玖兵,尹陈,等. 2013. 地面与井中观测条件下的微地震干涉逆时定位算法[J]. 地球物理学报,56(9):3184-3196,doi: 10.6038/cjg20130931.
Xu J P. 2011. Research of crack monitoring and its application [J]. Science Technology and Engineering (in Chinese),11(11): 2575-2577.徐剑平. 2011. 裂缝监测方法研究及应用实例[J]. 科学技术与工程,11(11): 2575-2577.
Zhang J Z,Liu H,Zou ZH,et al. 2015. Velocity modeling and inversion techniques for locating microseismic events in unconventional reservoirs [J]. Journal of Earth Science,26(4): 495-501.
Zhang S,Liu Q L,Zhao Q,et al. 2002. Application of microseismic monitoring technology in development of oil field [J]. GPP (in Chinese),41(2): 226-231.张山,刘清林,赵群,等. 2002. 微地震监测技术在油田开发中的应用[J]. 石油物探,41(2): 226-231.
Zou Z H,Zhou H W,Bian A,et al. 2015. An Evaluation of Reverse-Time Imaging of Clustering Earthquakes [J]. Journal of Earth Science,26(4): 548-555.
Zou Z H,Zhou H W,Gurrola H. 2014. Reverse-time imaging of a doublet of microearthquakes in the Three Gorges Reservoir region [J]. Geophysical Journal International,196(3): 1858-1868.