顺层断层对原岩层封闭能力的增强作用

为了解顺层断层对油气成藏的控制作用,实验研究了顺层断层岩的封闭能力.我们的数据证实,顺层断层具有较强的封闭能力,将大大地增强原岩层的封堵能力.其机理可归纳为四个方面:1)压性的正应力;2)以韧性及粘性变形为主,因为非能干岩层易塑性流变;3)涂抹效应强;4)面理化组构,垂直面理方向的封闭能力大大增强.如果盖层中发育顺层断层,盖层的封盖能力将被大大改善,将能够封盖更大的油气高度或者流体压力,利于形成更大规模的油气藏.

Enhancement effect of bedding faults on the sealing capacity of original rocks

To understand the control action of bedding faults during the formation of hydrocarbon accumulations,an experimental analysis on sealing capacity of bedding fault rocks was performed.Experimental results indicate that the sealing capacity of bedding faults is so high that it greatly enhances that of its original rock.The mechanisms summarized are as follows: 1) compressional normal stress;2) ductile and/or viscous deformation in bedding fault since incompetent bed is susceptible to plastic flow;3) higher likelihood of clay/shale smearing;4) foliation fabric whose sealing capacity is enhanced greatly in direction perpendicular to foliation.Therefore,cap rocks with bedding faults can seal higher hydrocarbon column height and fluid pressure,and thus facilitates the formation of larger scale hydrocarbon accumulations.