地质通报2026，Vol.45Issue(4)：678-692,15.DOI:10.12097/gbc.2024.04.008
致密砂岩储层全孔径分布、分形特征及其在致密油开采中的应用
Full pore size distribution,fractal characteristics of dense sandstone reservoirs and their application in tight oil exploitation
摘要
Abstract
[Objective]The Longdong area is located in the southwestern part of the Ordos Basin.Fine characterization of the full pore size distribution and fractal characteristics at different pore-throat scales in the Chang 7 dense sandstone reservoirs in this area is conducive to the quantitative prediction of favorable reservoirs.[Methods]This study employed the dense sandstone reservoirs from Chang 7 member of Yanchang Formation in Longdong area of Ordos Basin as the object of study,drilled 9 core samples from different wells,and utilized the means of casting thin section,scanning electron microscope,high-pressure mercury compression,and nuclear magnetic resonance(NMR),etc.Based on the analysis of reservoir characteristics,the NMR saturated water T2 spectrum was converted to a full aperture pore-throat size distribution curve using high-pressure pressurized mercury pore-throat distribution to analyze the fractal dimensions of different pore-throat types and their influencing factors.[Results]The results show that the pore types of the Chang 7 reservoir in the study area are mainly feldspar solution pores,intergranular pores and rock chip solution pores.The pore structure of the reservoir can be categorized into three types:Type Ⅰ,Type Ⅱ and Type Ⅲ,corresponding to the deterioration of physical properties,storage performance and seepage capacity in that order,with an increase in the proportion of micro-miniature pore throats,and the enhancement of non-homogeneity.[Conclusions]According to the full pore size distribution,the pore throats are categorized into micro pore throats(<0.01 µm),small pore throats(0.01～0.1 µm)and medium pore throats(0.1～1 µm),corresponding to the fractal dimensions increasing in order.As the main contributor to reservoir physical properties and reservoir space,the fractal dimension of the mesopores and small pores correlates well with the pore structure parameters,the mineral composition and content influence the complexity of the pore structure,and the clay minerals exacerbate the pore throat surface roughness and non-homogeneity,all of which correlate well and positively with the fractal dimension of the mesopore.The fractal dimension of tight sandstone reservoirs is correlated with physical properties,pore-throat structure parameters,and movable fluid parameters,and can be used to quantitatively characterize reservoir heterogeneity and establish reservoir classification criteria.关键词
鄂尔多斯盆地/陇东地区/致密砂岩/微观孔隙结构/全孔径孔喉大小/分形维数/致密油Key words
Ordos Basin/Longdong area/dense sandstone/microscopic pore structure/full aperture pore throat size/fractal dimension/tight oil分类
天文与地球科学引用本文复制引用
李陈,王巍,任利剑,李丛林,李梦茜,张雯,朱玉双..致密砂岩储层全孔径分布、分形特征及其在致密油开采中的应用[J].地质通报,2026,45(4):678-692,15.基金项目
国家科技重大专项《碎屑岩疏导层结构模型中成岩演化过程与流体流动特征》(编号:2017ZX05008-004-004-001)、国家自然科学基金项目《高热与超压背景的成岩响应及流体活动对储层成岩-孔隙演化的影响》(批准号:41972129) Supported by National Science and Technology Major Project(No.2017ZX05008-004-004-001)and National Natural Science Foundation of China(No.41972129) （编号:2017ZX05008-004-004-001）
