基于模式搜索的微地震速度反演——以渤海K油田为例

Pattern search algorithm for micro-seismic velocity inversion: A case study of K oilfield,Bohai Bay Basin

无论是井间地震还是水力压裂微地震,都需要知道相对准确的地层速度,笔者提出了一种新的微地震层速度反演方法,即模式搜索算法。首先利用测井资料和地质认识建立初始速度模型,然后拾取射孔记录的地震初至时间。由于有些地震记录激发时间难以确定,因此可利用各地震道之间的时差建立目标函数,最后利用模式搜索算法寻找目标函数最优解。模型试算结果及实际资料的应用都表明,该方法对于参数较少的层状介质模型有比较好的效果,为渤海水力压裂等技术提供一定借鉴意义。

Whether it is the cross-well seismic survey or hydraulic fracturing micro-seismic survey,all we need to know is the relatively accurate formation velocity.This paper presents a new method for micro-seismic layer velocity inversion.First,the logging data and geological knowledge are used to establish an initial velocity model,and then the first arrival time of the perforation record is picked up.Because the excitation time of some seismic records is difficult to be determined,the objective function is established by using the time difference between the seismic traces.Finally,the pattern search algorithm is used to find the optimal solution of the objective function.The model trial results and the application of actual data show that the method has better results for the layered media model with fewer parameters.The method provides some reference for the fracturing and other technologies in the Bohai Sea.