低渗透储层微观孔隙结构与可动流体饱和度关系研究

Relationship between Micro-pore Structure and Movable Fluid Saturation in Low Permeability Reservoir

针对常规压汞实验不能区别孔隙和喉道的弊端,应用恒速压汞技术对低渗透储层孔喉进行了定量评价,并深入分析了影响低渗透储层可动流体饱和度的主控因素。结果表明:渗透率越小,喉道半径分布范围越窄,其峰值也越小;反之,渗透率越大,喉道半径分布范围就越宽,其峰值也越大;不同物性的样品其孔隙分布特征不显著,主要体现为喉道分布特征不同。可动流体由孔隙和大喉道中的流体共同组成,与所处空间位置无关,只与孔隙和喉道半径有关。核磁共振可动流体的有效孔隙体积和有效喉道体积的共同下限半径也就是T2弛豫时间所对应的半径。

Since the conventional mercury injection experiment can not distinguish the pore and the throat, the contant-speed mercury injection was used to evaluate the reservoir quantitatively. Analysis of the control factors influences the movable fluid saturation. The results showed that the smaller the penetration was, the narrower the distribution of the throat radius was. Conversely, the bigger the penetration was, the wider the distribution of the throat radius was. The different physical properties of the pore distribution was not significant and it mainly reflected that the distribution of the throat was different. The fluid in the pore and the throat composites the movable fluid, which had nothing to do with the spatial location, and which only has relation with the radius. The common radius of the effective volume of the pore and throat of the NMR movable fluid was corresponding to the T2 relaxation in NMR.