氮气吸附法的致密砂岩孔隙结构分析

微观孔隙结构特征是研究储层中油气储存和运移的关键因素。选取鄂尔多斯盆地西峰地区长8段致密砂岩储层中的样品。通过氮气吸附实验,获得致密砂岩样品的孔隙结构参数。并讨论了各个结构参数与物性的相关性和影响因素。实验结果表明:根据IUPAC的分类,微观孔隙结构属于H3型。比表面积与孔隙度呈一般负相关,与渗透率具有较强的负相关性。微孔(<10nm)与中孔(10～50nm)对比表面积与孔隙体积贡献了80%。孔隙体积与孔隙度和渗透率的相关性均呈现一般正相关性。综合以上,较少的大孔发育可能是导致致密砂岩渗流能力较弱的原因。

Pore Structure Analysis of Tight Sandstone by Nitrogen Adsorption Method

The microscopic pore structure is a key factor in the study of hydrocarbon storage and migration in reservoirs.Select samples from the Chang 8 tight sandstone reservoir in the Xifeng area of the Ordos Basin.The pore structure parameters of the tight sandstone samples were obtained by nitrogen adsorption experiments.The correlation and influencing factors of various structural parameters and physical properties are discussed.The experimental results show that the microscopic pore structure belongs to H3 type according to the classification of IUPAC.The specific surface area is generally negatively correlated with porosity and has a strong negative correlation with permeability.Microporous(<10 nm) and mesoporous(10～50 nm) contrast surface area and pore volume contributed 80% The correlation between pore volume and porosity and permeability is generally positive.In summary, less macroporous development may be responsible for the weaker seepage capacity of tight sandstones.