转换波四参数速度分析方法在k71地区的应用(英文)
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摘要
胜利油田垦71地区多分量地震资料采用微型三分量数字检波器采集,该区上覆地层为砂岩和页岩交互层。由于转换波传播路径的非对称性和各向异性等因素的影响,造成了转换波资料中同相轴的非双曲现象。利用传统的基于各向同性理论进行速度分析,动校正时无法把同相轴拉平。本文使用转换波四参数理论估算非双曲效应,进行转换波速度分析和数据处理。这四个参数包括转换波叠加速度(VC2)、垂直速度比(y0)、等效速度比(yeff)和转换波各向异性系数(xeff)。此方法利用不同偏移距的动校正信息来估算不同的参数,确保了同相轴的同相叠加。将该方法应用于胜利油田垦71地区数字检波器三维转换波资料的处理中取得了较好的应用效果,提高了转换波资料的成像质量,改善了纵波一转换波的对层分析。
3-D converted-wave data were acquired using digital MEMS (micro-electromechanical system) three component (3C) sensors in the alternating sand and shale sequence in the overburden of the Shengli Ken-71 area. This gives rise to serious non-hyperbolic moveout effects in the converted-wave data due to both the asymmetrical ray path and anisotropic effects. Conventional velocity analysis and moveout correction based on isotropic methods do not flatten reflections events. Here, we use a four-parameter theory to evaluate these effects and process the data. These four parameters include the PS converted wave stacking velocity (VC2), the vertical velocity ratio (y0), the effective velocity ratio (yeff), and the anisotropy parameter (xeff). The method utilizes the moveout information at different offsets to estimate the different parameters and ensures that the events are properly aligned for stacking. As a result, this four-parameter theory leads to an improvement in imaging quality and correlation between the P-waves and converted-waves.
3-D converted-wave data were acquired using digital MEMS (micro-electromechanical system) three component (3C) sensors in the alternating sand and shale sequence in the overburden of the Shengli Ken-71 area. This gives rise to serious non-hyperbolic moveout effects in the converted-wave data due to both the asymmetrical ray path and anisotropic effects. Conventional velocity analysis and moveout correction based on isotropic methods do not flatten reflections events. Here, we use a four-parameter theory to evaluate these effects and process the data. These four parameters include the PS converted wave stacking velocity (VC2), the vertical velocity ratio (y0), the effective velocity ratio (yeff), and the anisotropy parameter (xeff). The method utilizes the moveout information at different offsets to estimate the different parameters and ensures that the events are properly aligned for stacking. As a result, this four-parameter theory leads to an improvement in imaging quality and correlation between the P-waves and converted-waves.
引文
Dai, H., 2003. Integrative analysis of anisotropy parameter and velocities for PS converted waves: 73rd Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 1577-1580.
Dai, H., and Li, X., 2001, Anisotropic migration and model building for 4-C seismic data: A case study from Alba: 71st Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 795-798.
Helbig, K., and Thomsen, L., 2005, 75-plus years of anisotropy in exploration and reservoir seismics: A historical review of concepts and methods: Geophysics, 70 (6), 9ND-23ND.
Li, X. Y., and Yuan, J. X., 2003, Converted-wave moveout and conversion-point equations in layered VTI media: theory and application: Journal of Applied Geophysics, 54,297-318.
Li, X, Y, and Yuan, J. X., 2005a, Converted-wave seismology in anisotropic media revisited, Part I: basic theory:, 2 (1) 26 - 41.
Li, X, Y, and Yuan, J. X., 2005b, Converted-wave seismology in anisotropic media revisited, Part II: application to parameter estimation:, 2 (3), 153-167.
Stewart, R. R., Gaiser, J. E., Brown, R. J., and Lawton, D. C, 2002, Converted-wave seismic exploration: methods: Geophysics, 67 (5), 1345 -1363.
Yuan, J., 2001, Analysis of four-component sea-floor seismic data for seismic anisotropy: PhD Thesis, University of Edinburgh.
Dai, H., and Li, X., 2001, Anisotropic migration and model building for 4-C seismic data: A case study from Alba: 71st Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 795-798.
Helbig, K., and Thomsen, L., 2005, 75-plus years of anisotropy in exploration and reservoir seismics: A historical review of concepts and methods: Geophysics, 70 (6), 9ND-23ND.
Li, X. Y., and Yuan, J. X., 2003, Converted-wave moveout and conversion-point equations in layered VTI media: theory and application: Journal of Applied Geophysics, 54,297-318.
Li, X, Y, and Yuan, J. X., 2005a, Converted-wave seismology in anisotropic media revisited, Part I: basic theory:
Li, X, Y, and Yuan, J. X., 2005b, Converted-wave seismology in anisotropic media revisited, Part II: application to parameter estimation:
Stewart, R. R., Gaiser, J. E., Brown, R. J., and Lawton, D. C, 2002, Converted-wave seismic exploration: methods: Geophysics, 67 (5), 1345 -1363.
Yuan, J., 2001, Analysis of four-component sea-floor seismic data for seismic anisotropy: PhD Thesis, University of Edinburgh.
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