摘要
准确的观测系统信息是高精度地震资料处理的基础,OBN检波点由于无法使用常规的GPS定位,通常需要专门的技术手段来确定检波点坐标.常见的检波点二次定位方法包括最小二乘法、近正四面体法、搜索法、拟合曲面法、等效速度法、矢量合成法等,但他们都基于直达波走时进行定位,浅水海域OBN资料仅在很小的偏移距内有直达波,因而难以适用;另一种常用的二次定位方法为折射波二次定位,因无法处理速度渐变、界面弯曲等情况,定位精度不高.针对浅水环境检波点定位不准的问题,本文提出了一种基于初至走时拟合的二次定位方法:首先在共检波点道集准确拾取初至时间,然后用多项式拟合初至时间和偏移距之间的关系曲线,用实际拾取走时和曲线上对应值的差对检波点坐标进行调整,多次迭代直至收敛.最后根据工区测量得到的水深值,用检波点X、Y坐标投影获得相应的Z坐标,即可获得准确的检波点三方向坐标.把本文方法应用于模拟资料和实际OBN资料的二次定位中,取得了理想效果.
Accurate observation system information is the foundation of high-precision seismic data processing.Due to the inability to use conventional GPS positioning for OBN receiver points,specialized technical means are usually required to determine the coordinates of the receiver points.Common secondary positioning methods for receiver points include least squares method,approximate tetrahedron method,search method,fitting surface method,equivalent velocity method,vector synthesis method,etc.However,they are all based on direct wave travel time for positioning.Shallow water OBN data only has direct waves within a small offset distance,making those methods difficult to apply.Another commonly used secondary positioning method is refracted wave secondary positioning,which has low positioning accuracy due to its inability to handle speed gradients,interface bending,and other situations.In response to the problem of inaccurate positioning of receiver points in shallow water environments,this paper proposes a positioning method based on first arrival travel time fitting.Firstly,the first arrival time is accurately picked up from the common receiver point gather.Then,a polynomial is used to fit the relationship curve between the first arrival time and offset.The coordinates of the receiver points are adjusted by the difference between the actual picked travel time and the corresponding value on the curve,and multiple iterations are carried out until convergence.Finally,based on the water depth values measured in the survey,the corresponding Z coordinates can be obtained by projecting the X and Y coordinates of the receiver points,thus obtaining accurate three-dimensional coordinates of the receiver points.The method proposed in this article has been applied to both simulated and actual OBN data,achieving ideal results.
作者
王忠成
葛大明
秦宁
刘培体
王敬阁
WANG ZhongCheng;GE DaMing;QIN Ning;LIU PeiTi;WANG JingGe(Geophysical Research Institute,SINOPEC Shengli Oilfield Company,Dongying 257022,China;Working Station for Postdoctoral Scientific Research,Shengli Oilfield,Dongying 257000,China)
出处
《地球物理学进展》
北大核心
2026年第1期481-490,共10页
Progress in Geophysics
基金
中石化股份公司科研攻关项目(P24093和P22729)
山东省博士后创新项目(SDCX-ZG-202400168)
胜利石油管理局博士后课题(YKB2313)联合资助。
关键词
海底节点
共检波点
初至走时
二次定位
OBN
Common receiver point
First-arrival travel time
Secondary positioning
