3D3C VSP imaging technology based on scattering time-distance relationship
YAN Yuanyuan1, QIN Li2, LUO Kun2, LU Jun1, WANG Yun1
1. School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China; 2. Southwest Branch, BGP Inc., CNPC, Chengdu, Sichuan 610213, China
Abstract：Acquired by special recording geometry, 3D3C (three-dimensional and three-component) VSP data can't be processed by conventional processing methods for surface seismic data. In addition, there are less applicable 3D3C-VSP imaging technologies with high precision, and there is less processing software for 3D3C-VSP data. To process 3D3C-VSP data, many iterations should be run for velocity analysis, and it is very difficult to get 3D imaging results. In this paper, we propose a method for velocity analysis and migration for 3D3C-VSP data. It is based on wave scattering theory and without iterating. First, we set up the time-distance curve equation of reflected wave in VSP data. Based on this equation, we move the amplitude at each time sample of the seismic trace to the corresponding reflective surface and extract the common-imaging-point gathers by interference stacking. Then, for the asymmetric ray-paths and inconsistent migration velocities of up-going and down-going waves, we convert the NMO corrected up-going waves in common-imaging-point gathers to virtual offset gathers with the characteristics of hyperbolic time difference. Eventually, through velocity analysis and NMO correction for the virtual offset gathers, we obtain high-precision PP and PS wave imaging profiles. This method was applied to the 3D3C-VSP seismic data of Well A in Sichuan Basin, and produced better imaging results than the conventional VSP-CDP stacking method.
Hokstad K,Sollie R,Petersen S. Horizontal resolution of 3-D VSP data[C]. SEG Technical Program Expanded Abstracts,2001,20:2135-2140.
[2]
Landrø M. Repeatability issues of 3-D VSP data[J]. Geophysics,1999,64(6):1673-1679.
[3]
朱光明. 垂直地震剖面方法[M]. 北京:石油工业出版社,1988.
[4]
庄东海. VSP旅行时反演应用于VSP-CDP转换[J]. 江汉石油学院学报,1991,13(2):30-36.ZHUANG Donghai. VSP traveltime inversion applied in VSP-CDP conversion[J]. Journal of Jianghan Petroleum Institute,1991,13(2):30-36.
[5]
杨飞龙,方金川,郭文强,等. 非零井源距VSP逆高斯束叠加成像[J]. 地球物理学进展,2020,35(3):1077-1084.YANG Feilong,FANG Jinchuan,GUO Wenqiang,et al. The inverse Gaussian beam stack imaging of nonzero-offset VSP[J]. Progress in Geophysics,2020,35(3):1077-1084.
[6]
Chen G M,Peron J,Canales L,et al. Rapid VSP-CDP mapping of 3D VSP data[J]. Geophysics,2000,65(5):1631-1640.
[7]
杨飞龙,李辉峰,孙辉,等. 基于正态分布权函数的VSP-CDP叠加成像[J].石油地球物理勘探,2020,55(1):101-110.YANG Feilong,LI Huifeng,SUN Hui,et al. VSP-CDP stack imaging based on the weight function of normal distribution[J]. Oil Geophysical Prospecting,2020,55(1):101-110.
[8]
李彦鹏,易维启,曾忠,等. VSP处理新技术及应用[J]. 石油地球物理勘探,2018,53(增刊2):42-49.LI Yanpeng,YI Weiqi,ZENG Zhong,et al. New processing approaches of VSP data[J]. Oil Geophysical Prospecting,2018,53(S2):42-49.
[9]
Zhang H H,Lu J,Chen B C,et al. Fluid prediction of a deep carbonate reservoir using walkaround 3D-3C vertical seismic profiling data[J]. Journal of Geophysics and Engineering,2020,17(1):35-52.
[10]
汪贵枫. 论F-K偏移[J]. 石油地球物理勘探,1983,18(1):20-29.WANG Guifeng. On F-K migration[J]. Oil Geophysical Prospecting,1983,18(1):20-29.
[11]
李渊. VSP逆时偏移方法研究[D]. 湖南长沙:中南大学,2013.LI Yuan. The Research on VSP Reverse-time Migration Method[D]. Central South University,Changsha,Hunan,2013.
[12]
Alok K S,Xander S,Verschuur E. VSP imaging using all multiples:Full wavefield migration approach[C]. SEG Technical Program Expanded Abstracts,2012,31:1-5.
[13]
陈生昌,马在田,陈林. 三维VSP数据的波动方程偏移成像[J]. 天然气工业,2008,28(3):51-53.CHEN Shengchang,MA Zaitian,CHEN Lin. Wave equation migration for 3-D VSP data[J]. Natural Gas Industry,2008,28(3):51-53.
Lou M,Cheng D J and Doherty F. Suppressing VSP migration artifacts and noise by selected-aperture migration and damped-least-square smoothing[C]. SEG Technical Program Expanded Abstracts,2009,28:4144-4148.
[16]
王华忠,徐蔚亚,王建民,等. VSP数据波动方程叠前深度偏移成像及立体地震成像[J]. 石油地球物理勘探,2001,36(5):517-525.WANG Huazhong,XU Weiya,WANG Jianmin,et al. Prestack depth migration of VSP data and stereosco-pic seismic imaging[J]. Oil Geophysical Prospecting,2001,36(5):517-525.
[17]
邹强,黄建平,雍鹏,等. 平面波优化差分算子弹性波逆时偏移[J]. 石油地球物理勘探,2020,55(5):1047-1059.ZOU Qiang,HUANG Jianping,YONG Peng,et al. An elastic-wave reverse-time migration method based on optimal finite-difference operators using a new plane wave solution[J]. Oil Geophysical Prospecting,2020,55(5):1047-1059.
[18]
陈可洋,王建民,关昕,等. 逆时偏移技术在VSP数据成像中的应用[J]. 石油地球物理勘探,2018,53(增刊1):89-93.CHEN Keyang,WANG Jianmin,GUAN Xin,et al. VSP data imaging with reverse time migration[J]. Oil Geophysical Prospecting,2018,53(S1):89-93.
[19]
Shi Y,Wang Y H. Reverse time migration of 3D vertical seismic profile data[J]. Geophysics,2016,81(1):S31-S38.
[20]
Dillon P B,Thomson R C. Offset source VSP surveys and their image construction[J]. Geophysical Prospecting,1984,32(5):790-811.
[21]
庄东海,肖春燕. VSP资料求层速度的射线追踪折线法[J]. 江汉石油学院学报,1994,16(4):50-53.ZHUANG Donghai,XIAO Chunyan. Ray-tracking method of computing interval velocities for VSP[J]. Journal of Jianghan Petroleum Institute,1994,16(4):50-53.
苏媛媛,李录明,赵俊省,等. 斜井三维VSP动校叠加处理方法[J]. 物探化探计算技术,2010,32(2):132-137.SU Yuanyuan,LI Luming,ZHAO Junsheng,et al.The processing methods of NMO correction and sta-cking in deviated 3D-VSP[J]. Computing Techniques for Geophysical and Geochemical Exploration,2010,32(2):132-137.
[24]
斯兴焱,李录明,胥良君,等. 三维VSP多波速度分析方法及应用[J]. 石油物探,2012,51(1):56-64.SI Xingyan,LI Luming,XU Liangjun,et al. 3D-VSP multiple velocity analysis method and its application[J]. Geophysical Prospecting for Petroleum,2012,51(1):56-64.
[25]
吴吉忠,刘成权,张建坤,等. 倾角域自适应孔径叠前时间偏移[J]. 石油地球物理勘探,2017,52(3):502-508.WU Jizhong,LIU Chengquan,ZHANG Jiankun,et al. Adaptive aperture prestack time migration in the dip angle domain[J]. Oil Geophysical Prospecting,2017,52(3):502-508.
