大庆长垣油田断层阴影地震正演模拟及校正方法

大庆长垣油田大断层下盘在地震剖面上普遍存在三角形的断层阴影区，其地震反射同相轴呈“上拉”或“下拉”、并伴随反射同相轴错断，导致利用地震资料进行断层、微幅度构造解释时存在陷阱。采用地震正演模拟技术，根据研究区实际地质情况建立了一系列二维地震正演模型，尝试定量分析断层阴影区地震反射特征。研究结果认为：断层两侧地层速度的横向变化是导致断层下盘断层阴影的根本原因，其中断层断距、低速层的存在等是长垣油田断层阴影区的主要影响因素；并进一步提出了密井网开发区利用三维空变速度场时深转换技术进行断层阴影校正的思路和方法，显著提高了大断层附近构造解释精度，为长垣油田更有效开发提供技术支撑。

Seismic forward modeling for correction of fault shadow zones in Changyuan Oilfield,Daqing

The footwall of large faults in Changyuan Oilfield,Daqing shows a triangular fault shadow zone on seismic sections.Seismic events of the shadow zones are often pulled up,pulled down,or uncontinuous,which lead to a great structural interpretation uncertainty.In order to quantitatively analyze characteristics of the fault shadow zone,a series of 2D forward models are built based on the geological information of the study area.According to our research,the fault shadow zones are caused by lateral velocity changes on both sides of faults,and fault throws and low velocity zones are the main influence factors of the fault shadow zone.The 3D space-variant velocity field is proposed to correct the fault shadow in dense well patterns,which improves effectively structural interpretation nearby the large fault and provides technical support for the future development of Changyuan Oilfield.