CT技术在致密砂岩微观孔隙结构研究中的应用——以鄂尔多斯盆地延长组长7段为例  

Application of CT Scanning System to Study of Micro-Pore Structure of Tight Sandstone: A Case Study of Chang-7 Member of Yanchang Formation in Ordos Basin

作　　者：尤源[1,2] 牛小兵[1,2] 李廷艳[1,2] 杨孝[3] 淡卫东[1,2] 

机构地区：[1]低渗透油气田勘探开发国家工程实验室,西安710018 [2]中国石油长庆油田分公司勘探开发研究院,西安710018 [3]中国石油长庆油田分公司油藏评价处,西安710018

出　　处：《新疆石油地质》2016年第2期227-230,共4页Xinjiang Petroleum Geology

基　　金：国家973项目(2014CB239003);国家自然科学基金(41390451)

摘　　要：为揭示致密砂岩复杂的孔隙结构特征,应用高分辨率CT技术,对鄂尔多斯盆地延长组长7段致密砂岩样品开展了定量研究。利用CT阈值差异识别样品中的孔隙和喉道,从而获得致密砂岩高精度二维及三维孔喉图像;应用数字岩心方法建立致密砂岩孔隙网络模型,并根据模型中的定量参数分析,获得孔隙及喉道的半径分布及其对储集空间的贡献率、孔喉连通性等特征,实现了长7段致密砂岩微观孔隙结构特征定量表征：长7段致密砂岩微米级孔喉连续分布;半径大于2μm的孔隙是长7段致密砂岩的主要储集空间;孔隙、喉道间具有一定的连通性,配位数主要为1~3.应用高分辨率CT技术可定量表征致密砂岩孔隙结构特征。In order to reveal the complicated pore structure characterisitcs of tight sandstone, this paper made a quantitative study of the tight sandstone sample from the Chang-7 member of Yanchang formation in Ordos basin by high-resolution CT scanning system, obtained the high-accuracy 2D and 3D pore throad images of it by using CT threshold differences, developed the tigh sandstone pore network model using digital core method, and conducted quantitative parameter statistics and analysis from this model, obtaining the radius distribution of pores and throats and their contributions and pore throat connectivity characterisitcs to the tight sandstone storage spaces, hence realizing the quantitative characterization of micro-pore structures of the tight sandstone. The results show that the tight sandstone of Chang-7 member of Yanchang formation in Ordos basin is characterized by continued distribution of micron pore throats, different contributions of different radius pores to the storage spaces, of which the pores with radius over 2 μm are the main storage spaces of it, and a certain connectivity between pores and throats, with coordination number from 1 to 3.

关 键 词：鄂尔多斯盆地 延长组 致密砂岩 孔隙 喉道 CT技术 

分 类 号：TE112.3[石油与天然气工程—油气勘探]