埕岛油田低级序断层综合识别及其在注水开发中的应用

Comprehensive Identification of Low-Order Fault and Its Application in the Waterflooding Development of Chengdao Oilfield

受多期构造活动的影响,埕岛油田发育较多利用常规手段难以识别的低级序断层,在油田开发中后期对于精细注水开发造成了很大的影响。综合利用多种叠后地震资料处理技术,对低级序断层进行了识别,并结合精细地层对比及油藏动态资料分析等方法,对低级序断层进行验证和刻画。结果表明,低级序断层与高级序断层在剖面上和平面上形成了多种组合样式,依据形成的应力不同将其分为拉张正断层、拉张-走滑断层和走滑断层3类,拉张正断层主要分布在高级序断层的上盘,拉张-走滑断层与走滑断层则主要分布在高级序断层的两侧。通过低级序断层的识别,有效解决了埕岛油田西北区4A井组Ng_3~1层的注采对应矛盾和北区Ng_(1+2)~3层的油水关系矛盾,除此之外,在油田开发后期,低级序断层对剩余油的分布具有一定的控制作用,研究低级序断层对于指导剩余油挖潜具有重要的意义。

Multi-stage tectonic activities results in abundant low-order faults in the Chengdao Oilfield.These loworder faults cannot be accurately identified by conventional means and significantly influence the fine waterflooding performance in the middle-late development stage.Multiple post-stack seismic data processing techniques were used to identify these low-order faults.Fine stratigraphic correlation and reservoir production analysis were also adopted to verify and characterize these low-order faults.Result indicates that there are multiple combination patterns of low-order and high-order faults along the lateral and longitudinal directions.These faults can be classified into three categories according to the initial stress,including tensile normal fault,tensile-slip fault and strike-slip fault.The tensile-normal fault mainly distributes on the upper wall of high-order fault.Tensile-slip and strike-slip faults mainly distribute on the both sides of high-order fault.Comprehensive identification of the low-order faults effectively improves the injection-production contradictions of Layer Ng3^1 and Layer Ng1+2^3 of the Wellgroup 4A in northwestern Chengdao Oilfield.In addition,the remaining oil distribution is also dependent on the low-order fault in the late development stage.This low-order fault research is of great significance for the recovery of remaining oil.