鄂尔多斯盆地姬塬长2油层组低渗透砂岩孔隙结构对储层质量影响

Influence of Pore-Throat Sizes on Reservoir Quality of Low-Permeability Sandstone of Chang 2 Oil-Bearing Bed from the Jiyuan,Ordos Basin

微观孔隙结构是低渗透砂岩储层质量重要影响因素之一。通过铸体薄片、常规物性及高压压汞等分析表明,鄂尔多斯盆地姬塬地区长2油层组低渗透砂岩储层孔隙度、渗透率与最大孔喉半径、中值孔喉半径、分选系数、变异系数间具正相关关系,与孔喉半径均值(φ)、结构系数间具负相关关系,与非汞饱和孔喉体积、歪度间无明显相关关系。这些孔隙结构参数可简化为3个相对独立主因子:①有效半径因子;②无效半径因子;③弯曲度因子。

The pore-throat size is one of important influential factors to the reservoir quality of low-permeability sandstones.The analyses of the resin impregnated thin sections,routine physical properties and high-pressure mercury injection indicate that there are distinct positive pertinences between the porosity, permeability and the largest pore-throat radius,median pore-throat radius,sorting coefficient,variation coefficient,the distinct negative pertinences between the porosity, permeability and the mean pore-throat radius,texture coefficient,the uncertain pertinences between the porosity, permeability and the non-mercury saturated pore-throat volumes,skewness.These pore-throat size parameters could be simplified to three relatively independent main factors：the first main factor-effective radius factor, the second main factor-invalid radius factor, the third main factor-curvature factor.