贝尔凹陷布达特群垂直裂缝垂向封闭性演化特征

Sealing Ability Vertical Changes of the Vertical Fractures in Budate Group of Beier Depression,Hailaer Basin

通过岩心观察和成像测井资料分析,发现贝尔凹陷布达特群垂直裂缝较发育,其形成与分布受断裂控制。利用SiO2或CaCO3沉淀胶结所需要的镜质体反射率值,对贝尔凹陷布达特群垂直裂缝目前垂向封闭性进行了评价。凹陷大部分地区开启,仅在凹陷少部分地区封闭,封闭区在凹陷中部呈环带分布,在凹陷边部呈条带分布。贝尔凹陷布达特群垂直裂缝现今垂向封闭性差于地质历史时期垂向封闭性,油气保存条件变差,造成油气大量散失,这可能是目前贝尔凹陷能在布达特群找到一批油气藏的重要原因之一。

By means of cores observation and analysis of imaging well-logging data, it shows that vertical fractures were developed in Budate Group of Beier depression. The formation and distribution of vertical fractures were controlled by the faults. By the vitrinite reflectance required in deposition of silica or carbonate, the vertical seal of vertical fractures in Budate Group of Beier depression now was studied. It shows that vertical fractures are open in most of the area, and closed only in a few areas of the depression. Sealed areas distributed in stripe on the edge of the depression and in ring in the centre of the depression. The vertical sealing ability of the vertical fractures in Budate Group of Beier depression in geohistorical periods is better than that of the present. Oil ＆ gas preservation conditions become worse and worse, a great deal of oil- gas has been lost in the past.