一种近地表异常区的静校正方法及应用效果
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摘要
在地震勘探中,模型法、折射法、层析法等是目前常用的基准面静校正方法。对各种静校正方法的基本原理与适用条件归纳分析发现,它们都以地表一致性和地震反射垂直穿过近地表地层为前提,然而,在复杂地质条件下,尤其在长波长静校正存在的地区,不能满足地表一致性假设。实际上,近地表存在速度异常区时,地震波则很少垂直传播,静校正量与射线穿过近地表的距离和速度密切相关,在反射地震勘探中,远近偏移距的反射波穿过近地表时会产生不同的静校正量,利用这一点将目的层的异常作为近地表异常的判别准则,可以解决表层异常区的长波长静校正问题。对这一方法进行了论述,应用生产后较好地解决了因近地表异常造成的静校正问题。
Model method,reflection method and tomographic method are common datum static correction methods at the present time.Summarization and analysis of the fundamental principles of various static correction methods and applicable conditions indicate the precondition that all of them are based on the surface consistency and vertical penetration of near surface by seismic reflection.However,under the complicated geological conditions,particularly in the region where static correction of long wavelength exists,it is difficult to meet the assumption of surface consistency.In fact,when the abnormal zone of velocity exists,seismic waves seldom propagate vertically.The distance for the statics and rays to go through near surface is closely related to the velocity.In reflection seismic exploration,far and near offset reflection waves can generate different statics at the time of penetrating near surface.If this phenomenon is used as a principle for to judge the abnormality of target formation as the abnormality of near surface,the problem of long wavelength static correction in the abnormal zone of surface can be solved.This article elaborates on this method,which has desirably solved the static correction problem caused by the near surface abnormality since it was used for production.
Model method,reflection method and tomographic method are common datum static correction methods at the present time.Summarization and analysis of the fundamental principles of various static correction methods and applicable conditions indicate the precondition that all of them are based on the surface consistency and vertical penetration of near surface by seismic reflection.However,under the complicated geological conditions,particularly in the region where static correction of long wavelength exists,it is difficult to meet the assumption of surface consistency.In fact,when the abnormal zone of velocity exists,seismic waves seldom propagate vertically.The distance for the statics and rays to go through near surface is closely related to the velocity.In reflection seismic exploration,far and near offset reflection waves can generate different statics at the time of penetrating near surface.If this phenomenon is used as a principle for to judge the abnormality of target formation as the abnormality of near surface,the problem of long wavelength static correction in the abnormal zone of surface can be solved.This article elaborates on this method,which has desirably solved the static correction problem caused by the near surface abnormality since it was used for production.
引文
[1]郑鸿明,杨晓海,崔琴,等.基准面校正的理论研究及误差分析[J].新疆石油地质,2005,23(1):79～81.
[2][美]Mike Cox著.反射地震勘探静校正技术[M].李培明,柯本喜等译.北京:石油工业出版社,2004.
[3]谭昌勇,王彦春,张伟宏,等.静校正方法在黄土塬地区的联合应用[J].石油物探,2009,48(3):252～257.
[2][美]Mike Cox著.反射地震勘探静校正技术[M].李培明,柯本喜等译.北京:石油工业出版社,2004.
[3]谭昌勇,王彦春,张伟宏,等.静校正方法在黄土塬地区的联合应用[J].石油物探,2009,48(3):252～257.
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