砂泥互层断点组合类型及其合理性分析——以大庆长垣萨尔图油田为例

Fault breakpoint assemblage types of sand-mud inter-beds:an example of Saertu Oilfield in Daqing

基于对复杂断块断点归属的认识,在总结前人研究成果的基础上,从断裂组合形态、断裂二分结构、断层垂向分段生长等方面归纳了断距小于5m的砂泥互层断点组合类型,并分析了各类断点组合的合理性,结果表明:①存在断裂相交、单一断裂破碎带、断裂垂向分段、地震断层端部等4类断点组合类型,建立了相应成因机制的断点组合三维、平面、剖面对应关系。②断裂相交型断点主要依据地震断层识别进行归类;断距变化较大,断点间距不大于40m,小断距断点属破碎带内断点;断距大小相当,断点发育部位之间存在塑性岩层段,归属的断裂具有同期性,属于释放型垂向分段断点;厚度较大的弱能干性层,且归属断裂具有多期性,则属于压缩性垂向分段断点;位于断层延伸方向上、且符合断距-距离曲线规律的断点属于地震断层端部断点。③对研究区断点重新组合,新组合断距为5~10m的断点52个,整体断点组合率达到93.3%,断距小于5m断点的组合率为81.8%,为断裂特征分析、断层模型构建以及断裂边部剩余油挖潜提供了精确的断层数据。

Based on the understanding of the fault breakpoint ownership of complex fault blocks and on previous studies results,a research of fault breakpoint assemblage types of sand-mud inter-beds in Saertu Oilfield,Daqing is carried out.The fault breakpoint assemblage types with throw of less than 5 min sand-mud inter-beds are summarized from the aspects of fault combination,fault binary structure,fault vertical segmental growth,and seismic fault terminal portion.The following observations are obtained:(1)There are four types of fault breakpoint assemblage,such as fault intersection,single fault fracture zone,fault vertical segment,and the seismic fault terminal portion.The corresponding representation of theses breakpoint assemblages in space,plane,and section is established;(2)Breakpoints of fault intersection are mainly classified by seismic fault identification,their throws vary greatly,and the breakpoint vertical distance is less than 40 m.Fault breakponts with small throws belong to fault fracture zones.For releasing vertical segmental breakpoints,throws are almost equal,and there are plastic layers among breakpoints.For restraining vertical segmental fault breakpoints,there are plastic layers with a larger thickness,in which Faults experienced multistages.Terminal portion breakpoint of seismic fault is located in the direction of fault extension and accords with the law of fault throw-distance curve;(3)Based on this research,52 breakpoints with throws from 5 mto 10 mare identified,the overall breakpoint assemblage ratio reaches 93.3%.The breakpoint assemblage ratio with throws smaller less than 5 mis 81.8%.It provides accurate and useful data for of fault characteristics analysis,fault model building,and remaining oil development.