复杂山前带有偏VSP数据处理方法研究

Offset VSP data processing method for complex piedmont

1.中国地质大学(武汉),湖北武汉430074;2.中国石油天然气集团公司东方地球物理勘探有限责任公司,河北涿州072751;3.中国石油天然气股 份有限公司塔里木油田分公司,新疆库尔勒841000

Zhang Shan,China University of Geosciences (Wuhan),Wuhan 430074,China

复杂山前带具有地表起伏大、地下逆掩推覆构造倾角大、断层关系复杂等地质特征,采用传统有偏VSP数据处理方法难以解决复杂山前带构
造成像问题。为此,针对波场分离、静校正、成像方法和速度建模等VSP处理的几个关键环节提出了新的思路和方法。波场分离采用了F-K滤波与
逐点偏振滤波相结合的方法,实现了复杂波场的有效分离。为解决静校正问题,改变了VSP成像策略,由传统的时间域成像改为深度域成像,成像后
再进行统一基准面校正,从而消除了多方位有偏VSP传统成像剖面间的闭合差。在成像方法上,采用克希霍夫深度域积分成像方法,并根据VSP观测
的特点,采用零偏VSP与有偏VSP初至时间计算积分成像中的关键参数——观测时间。将该方法应用于库车复杂山前带相邻两口井的VSP资料处理
中,处理结果与钻井结果吻合良好。

Complex piedmont is characterized by rugged surface,large-dip overthrust nappe structure,complex fault relations,etc.
Traditional offset VSP data processing method cannot solve the imaging problem for the structures in complex piedmont.
Therefore,some new ideas and method were proposed aiming at several key steps for VSP data processing,such as wavefield
separation,imaging method and velocity modeling. For wavefield separation,we combined F-K filtering and point-by-point
polarization filtering to realize complex wavefield separation. In order to solve the static correction problem,the VSP
imaging strategy was changed from traditional time-domain imaging into depth-domain imaging,then datum correction was carried
out uniformly after imaging,which can remove the closure difference among the imaging sections obtained from tranditional
multi-azimuth offset VSP processing. Meanwhile,Kirchhoff depth-domain integral imaging method was utilized. In terms of the
characteristics of VSP observation,zero-offset VSP and offset VSP fist arrival were adopted to calculate the observation
time,which is the key parameter in integral imaging. The method was applied to the VSP data processing in two adjacent wells
at the complex piedmont in Kuche area,and the result is well coinciding with the drilling data.

10.3969/j.issn.1000-1441.2012.02.009