低渗透裂缝性油藏注水突进特征分析——以八区下乌尔禾组油藏为例

Analysis of Waterflooding Dash Characteristics of Fractured Reservoir with Low Permeability

八区下乌尔禾组油藏裂缝发育,尤其是垂向上的裂缝延伸高度较大。实验区内4个井组的井间示踪剂监测结果表明,示踪剂产出持续时间短,产出曲线尖而陡,注入水主要沿东西方向上的井排突进,甚至推进到二线和三线油井,且推进速度快,注水波及系数较小。注采井之间主要靠裂缝进行连通,且注采井之间的裂缝发育的规模和类型差异较大,注采井之间裂缝连通的条数从1条到几条不等,裂缝在不同层位之间的沟通作用致使层间窜流显像普遍存在。当注采井之间没有裂缝连通时,注入水就会聚集在注水井井底附近形成一个新的水体。

In the lower Wuerhe Formation in the eighth district,reservoir fissures develop well and,especially,the vertical fissure extends higher.Monitoring result from tracers between four well groups within experimental area shows that the duration of tracer production is short,the production curve is pointed and steep,injected water dashes to west and east directions and even to second-third-line wells with less waterflooding sweep efficiency at high speed.Interjection wells and production wells are connected mainly by fissures which develop in different scale and type and link them with different numbers of fissures.Therefore,the connection role fissures play in different layers makes layer cross flow common.Without connection,injected water would gather at the bottom of a water injection well to form a new water body.