1. School of Geosciences,China University of Petroleum,Qingdao 266580,China 2. Ya'an City Yucheng District Natural Resources and Planning Bureau,Ya'an 625000,China 3. School of Geophysics and Measurement-control Technology,East China University of Technology,Nanchang 330013,China
With the increasingly refined and complicated exploration and development goals,the least-squares inverse-time migration based on inversion theory has gradually become the current development trend.In order to make the least-squares reverse-time migration better for the exploration and development of oil and gas reservoirs,analyzing the imaging effects under different conditions helps to guide the processors to make appropriate adjustments in the actual data processing.For this reason,in view of the migration velocity error and the noise in seismic data in the actual exploration process,the authors made a comparative study of the imaging effects of least-squares reverse-time migration under different conditions.The results show that,in the case of systematic errors in migration velocity,the imaging depth of interface will have errors,and it is difficult for the imaging profile to reflect the actual structure;the influence of smoothed migration velocity errors on least-squares reverse-time migration is much smaller than the systematic error of migration velocity,and proper smoothing can improve the imaging quality,but excessive smoothing can affect the imaging quality;the least-squares reverse-time migration can suppress part of the noise;nevertheless,as the noise in the seismic record increases,the weak reflection gradually cannot be resolved,and it is difficult to reflect the underground structure.
马振, 孙成禹, 彭鹏鹏, 姚振岸. 速度误差和地震噪声对最小二乘逆时偏移的影响分析[J]. 物探与化探, 2020, 44(2): 329-338.
Zhen MA, Cheng-Yu SUN, Peng-Peng PENG, Zhen-An YAO. An analysis of the influence of velocity error and seismic noise on least squares reverse-time migration. Geophysical and Geochemical Exploration, 2020, 44(2): 329-338.
Deng W Z, Li Z C, Wang Y G , et al. The least-squares reverse time migration for visco-acoustic medium based on a stable reverse-time propagator[J]. Geophysical and Geochemical Exploration, 2015,39(4):791-796.
Yoon K. Challenges in reverse-time migration [C]//SEG Technical Program Expanded Abstracts, 1999.
Ye Y M, Zhuang X J, Hu B , et al. Velocity sensitivity analysis of typical pre-stack depth migration methods[J]. Oil Geophysical Prospecting, 2012,47(4):552-558.
Zhu J, Lines L, Gray S . Smiles and frowns in migration/velocity analysis[J]. Geophysics, 1998,63(4):1200-1209.
Parkes G E, Hatton L. Toward a systematic understanding of the effects of velocity model errors on depth and time migration of seismic data [C]//SEG Technical Program Expanded Abstracts, 1949,3(1):348.