低渗透砂岩石油运移及成藏特征模拟实验

采用计算机控制和改变低渗透岩心中流体注入压力的方法,研究低渗透砂岩中石油运移及成藏的特征.模拟实验初步研究结果表明:1)低渗透岩层石油运移表现为非达西流,渗流曲线主要为上凹型曲线,其次为变性达西流曲线;2)岩心渗透率大小对渗流曲线的位置、非线性段的曲率和变化范围及直线段在压力梯度轴的截距具有很大的影响;3)低渗透岩心中含油饱和度的增大过程可划分为快速增长、缓慢增长和稳定3个阶段,其最终含油饱和度大部分在35%～60%;4)低渗透岩心的含油饱和度与孔隙度、渗透率的关系并不是简单的线性关系,但是充注动力与含油饱和度具有相对较好的正相关关系.

An experimental study on oil migration and accumulation in low-permeability sandstone

An experimental study of oil migration and accumulation in low-permeability sandstone is performed through injecting fluid into core samples from low-permeability sandstone under computer-controlled pressures.The preliminary results indicate that(1) oil migration in low permeability beds presents the features of non-Darcy flow and most of the flow curves take the concave upward shape and some of them are modified Darcy flow curves;(2) the core permeability has a strong impact upon the locations of flow curves,curvatures and variation range of the non-linear parts,and the intercepts of the linear portions on the pressure gradient axis;(3) the oil saturation in low-permeability cores increases in three stages,including rapid,slow and stable growth,with the final oil saturation mainly ranging from 35% to 60%;and(4) the relationship between oil saturation and porosity or permeability in low permeability cores is not simple linear relationship,but a positive correlation exists between the injection pressure and the oil saturation.