三维VSP多波速度分析方法及应用

3D-VSP multiple velocity analysis method and its application

(1.成都理工大学“油气藏地质及开发工程”国家重点实验室,四川成都610059;2.中国石油化工股份有限公司西南油气分公司勘探开发研究院德阳分院,四川德阳618000；3.中国石油化工股份有限公司多波地震技术重点实验室，四川德阳618000)

Si Xingyan,State Key Lab of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China

针对三维VSP多波速度分析问题,研究并实现了三维VSP上行反射纵波及转换波的速度分析方法。该方法可求取接收点以下反射层的多波速度,填补了常规VSP速度分析方法中仅依靠下行波初至求取接收点以上地层速度的缺陷。该速度分析方法包含非零偏VSP多波时距曲线公式、纵波反射点计算、转换波转换点的迭代算法及在没有横波初至信息的情况下求取检波点处横波速度的方法。在此基础上,建立了三维VSP多波速度分析流程和步骤。应用于理论VSP多波资料及实际斜井三维VSP多波资料的处理,得到了与地面地震时间坐标一致的多波叠加速度模型、多波动校正道集及叠加剖面。处理结果证明了该方法的正确性和有效性。

Aiming at the 3D-VSP multiple velocity analysis problems,the velocity analysis method of 3D-VSP reflected P-wave and converted wave was stuied and realized,which can acquire the multiple velocity of the reflection layers below the receiving points and infill the defect of conventional VSP velocity analysis method to obtain the formation velocity above the receiving points only by first break of down-going wave.3D-VSP multiple velocity analysis includes non-zero-offset VSP multiple moveout equations,caculating the reflection point of reflected P-wave,iterative algorithm of converted point of reflected converted-wave,as well as the method to determine the S-wave velocity at the geophone location without S-wave first break data Based on the above methods,combined with batch processing and interactive method,we built the workflow and steps of 3D-VSP multiple velocity analysis.Moreover,the method was applied on theoretical VSP multiple data and actual 3D-VSP multiple data of deviated well.As a consequence,we obtained the multiple stack velocity model,multiple moveout gathers and stack profile which were coinciding with the time coordinates of surface seismic.The processing results proved the correctness and effectiveness of the method.

10.3969/j.issn.1000-1441.2012.01.008