页岩纳米孔隙分形特征及其对甲烷吸附性能的影响

发布时间：2018-03-30 15:37

本文选题：页岩气　切入点：分形维数　出处：《科学技术与工程》2017年02期

【摘要】：为了更好地了解页岩纳米孔隙特征及其对甲烷吸附性能的影响,对四川盆地上三叠统须五段的6个页岩样品进行了分形分析。通过对氮气吸附/解吸等温线的分析表明,页岩在相对压力为0~0.5和0.5~1时具有不同的吸附特征。利用Frenkel-Halsey-Hill(FHH)方程计算得到两个分形维数D_1和D_2。甲烷的吸附性能随着D_1和D_2的增加而增强,其中D_1对吸附有着更显著的影响。进一步研究表明,D_1代表由于页岩表面不规则性产生的孔隙表面分形特征;而D_2代表的是孔隙结构分形特征,其主要受页岩组分(有机碳含量、石英、黏土矿物等)和孔隙参数(平均孔径、微孔含量等)控制。更高的分形维数D_1对应更不规则的孔隙表面,为甲烷吸附提供更多的空间。而更高的分形维数D_2代表更复杂的孔隙结构以及孔隙表面更强烈的毛细凝聚作用,进而增强甲烷的吸附能力。因此,页岩孔隙表面越不规则,孔隙结构越复杂,甲烷吸附能力越强。
[Abstract]:In order to better understand the pore characteristics of shale and its effect on methane adsorption, fractal analysis was carried out on six shale samples from Xuwu member of Upper Triassic in Sichuan Basin. The analysis of nitrogen adsorption / desorption isotherm showed that. Shale has different adsorption characteristics at relative pressure of 0.5 and 0.5 ~ 1.The Frenkel-Halsey-Hiller-FHH equation is used to calculate two fractal dimensions D _ 1 and D _ 2. The methane adsorption performance increases with the increase of D _ S _ 1 and D _ S _ 2. Further studies show that D-1 represents the fractal characteristics of pore surface due to the irregularity of shale surface, while D-2 represents fractal characteristics of pore structure, which is mainly affected by shale fractions (organic carbon content). Quartz, clay, etc.) and pore parameters (average pore size, micropore content, etc.). Higher fractal dimension D1 corresponds to more irregular pore surfaces, The higher fractal dimension D _ 2 represents the more complex pore structure and the stronger capillary condensation on the pore surface, thus enhancing the adsorption capacity of methane. Therefore, the more irregular the shale pore surface, the more irregular the pore surface is. The more complex the pore structure, the stronger the methane adsorption capacity.
【作者单位】：中国石油大学(北京)油气资源与探测国家重点实验室;中国石油大学(北京)非常规天然气研究院;中国石油大学(北京)非常规油气协同创新中心;
【基金】：国家科技重大专项(2016ZX05034-001) 国家自然科学基金(41472112)资助
【分类号】：P618.13

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