陆相成熟烃源岩区连通砂体对油气运移的控制作用

Control of Connected Sandbody on Oil-gas migration in Terrestrial Facies Mature Hydrocarbon Source Rock

基于成熟烃源岩稳态连续排烃机制,分析陆相成熟烃源岩区内连通砂体对油气运移的控制作用,并深入探讨烃源岩内砂体与烃源岩的接触面积、砂泥互层烃源岩层系中砂岩含量、砂体物性、砂体分布及其连续性对排烃效率的影响。结果表明:将连通砂体与烃源岩的接触类型分为垂向沉积相变接触型、侧向沉积相变接触型及交错复合接触型,其中前两者是烃源岩-连通砂体的主要接触类型;烃源岩-连通砂体配置组合以在异常压力驱动下的稳态连续排烃为主;烃源岩内砂体与烃源岩的接触面积越大、砂岩含量越大、砂岩物性越好、砂体分布稳定及连续性好有利于成熟烃源岩排烃,则排烃效率越大,进而控制主要排烃方向和资源量。烃源岩内连通砂体对油气二次运移的作用主要取决于其与烃源岩外连通砂体的分布连续性与物性连通性。如果烃源岩内砂体是孤立的,油气无法运移出烃源岩区,则形成烃源岩内油气藏;如果烃源岩内砂体与烃源岩外砂体分布连续且物性连通,则油气运移距离大,可在更为有利的圈闭分布区成藏。

Based on the mechanism of steady state continuous hydrocarbon expulsion of mature hydrocarbon source rock, the control of connected sandbody on oil-gas migration in terrestrial facies mature hydrocarbon source rock was analyzed, and the effects of contact area between hydrocarbon source rock and sandbody in it, content of sandstone in the bed series of hydrocarbon source rock with interbedded sandstone and mudstone, physical property, distribution and continuity of sandbody to expulsion efficiency of hydrocarbon were discussed. The results showed that the contact type between connected sandbody and hydrocarbon source rock was divided into vertical sedimentary facies transition contact, lateral sedimentary facies transition contact and staggered compound contact, and the vertical and lateral sedimentary facies transition contacts were the main types; the type for the combination of connected sandbody and hydrocarbon source rock was mainly steady state continuous hydrocarbon expulsion driven by abnormal pressurel the greater contact area, content of sandstone, physical property, distribution and continuity of sandbody, the better expulsion efficiency of hydrocarbon of mature hydrocarbon source rock, and then the main hydrocarbon expulsion direction and resources were controlled. The effect of connected sandbody in hydrocarbon source rock on secondary oil-gas migration depended on the continuity of distribution and connectivity of physical property between the connected sandbodies inside and outside hydrocarbon source rock. If sandbody in hydrocarbon source rock was isolated and oil and gas could not migrated outside the rock, reservoir inside hydrocarbon source rock was formed ~ if the continuity of distribution and connectivity of physical property between the sandhodies inside and outside hydrocarbon source rock were great, the distance of oil-gas migration was large, and the reservoir formed in more favorable closed loop area.