叠前时间偏移技术在东濮凹陷应用的认识

东濮凹陷断裂复杂,多断块、多套生储盖组合,叠后偏移成像效果不佳。叠前时间偏移技术在这一复杂断块区的应用可以改善成像效果。研究提出了一套以速度迭代为核心、地质信息为约束的求取偏移速度场的改进方法,提高了偏移速度的精度;通过对偏移孔径、最大偏移角度、射线路径、去假频4个关键参数处理的分析,得出适合东濮凹陷地震资料特点的经验参数,减少了以后处理过程中的试验工作量和参数试验的盲目性,有效地提高了处理效率。通过叠前时间偏移,提高了复杂断块地区成像精度,能够准确地落实断层位置和认识断块之间的关系,与井资料的吻合程度较高,取得了明显的地质效果。

The Application and Recognition of Prestack Migration Technology in Dongpu Depression

The features of Dongpu depression in Zhongyuan Oilfield include complex faults,many faulted blocks,multiple sets of source reservoir seal assemblages.It is difficult for post-stack migration to get perfect migration imaging effect in complex faulted blocks.However,pre-stack migration can improve the imaging effect.An effective Optimized Method for obtaining migration velocity field for pre-stack time migration is presented,which is based on velocity iteration and constrained by geological information.The method can improve accuracy of migration velocity.Through analyzing four key parameters of pre-stack time migration such as migration aperture,maximum migration angle,ray trace and anti-aliased,some parameter value is proposed,which is effective for the seismic data in Dongpu depression.Consequently,testing workload of processing procedure and blindness of parameter test are decreased so as to increase processing efficiency.Through pre-stack time migration,imaging accuracy in complex faulted blocks is improved,the positions of faults can be accurately ascertained, the relationships among faulted blocks are clarified,which are highly accorded with well data.