基于扫描电镜的页岩有机孔隙空间定量表征

Quantitative Characterization of Shale Organic Pore Space Based on SEM

对于富含有机质的页岩储层来说,孔隙度是评价油气储量的关键参数之一,有机孔隙的存在又对岩石孔隙空间具有重要贡献,因此,研究页岩储层有机孔隙空间是有必要的。本文结合氩离子抛光扫描电镜(SEM)资料和图像分割技术,以川南永川区块YY2井龙马溪组页岩储层为例,对纳米有机孔隙的形态特征和有机孔隙度进行分析研究,研究表明:YY2井龙马溪组有机孔隙较发育,SEM图像中有机孔隙直径差异很大,对龙马溪组6块岩样的SEM图像进行处理,得到的有机质面孔率在0.97%~8.90%之间,个别样品孔径较小,面孔率在1%以下。利用面孔率和有机质含量计算有机孔隙度,计算得到的有机孔隙度在0.12%~0.75%范围内,均值为0.39%,占据岩石孔隙度的10.66%。

For shale reservoirs that are rich in organic matter,the porosity is one of the most key parameters for evaluation of oil and gas reserves,the existence of the organic pore make important contribution to the rock pore space,therefore,research on organic shale reservoir pore space is necessary.In this paper,taking the Longmaxi Formation shale reservoir of YY2 well in yongchuan block of South Sichuan as an example,the morphological characteristics and organic porosity of nanometer organic pores are analyzed and studied by combining the argon ion polishing scanning electron microscope data and image segmentation technology.The research shows that:The organic pores of the Longmaxi Formation in the YY2 well are relatively developed.The SEM images have large differences in the diameter of the organic pores.The SEM images of the six rock samples of the Longmaxi Formation are processed,and the obtained organic matter plane porosity is between 0.97%and 8.90%,and the aperture of some samples was small,and the plane porosity was below 1%.organic porosity calculated using the plane porosity and organic matter content which is in the range of 0.12%-0.75%,the average value is 0.39%,and accounts for 10.66%of the rock's porosity.