四川盆地凉高山组全尺寸孔隙半径分布表征方法  

Characterization Method for Full⁃Size Pore Radius Distribution in Lianggaoshan Formation,Sichuan Basin

作　　者：赵吉儿 冉崎[1] 谢冰[1] 赖强[1] 白利 朱迅 ZHAO Ji’er;RAN Qi;XIE Bing;LAI Qiang;BAI Li;ZHU Xun(Research Institute of Exploration and Development,Southwest Oil&Gas Field Company,PetroChina,Chengdu,Sichuan 610095,China;Southwest Oil&Gas Field Company,PetroChina,Chengdu,Sichuan 610056,China)

机构地区：[1]中国石油西南油气田分公司勘探开发研究院,成都610095 [2]中国石油西南油气田分公司,成都610056

出　　处：《新疆石油地质》2025年第2期181-191,共11页Xinjiang Petroleum Geology

基　　金：中国石油科技项目(2023ZZ15YJ02)。

摘　　要：四川盆地下侏罗统凉高山组页岩储集层发育,孔隙为纳米级,具有低孔低渗、孔隙类型多样、孔隙结构复杂及孔隙半径分布范围广的特点,因此,准确评价页岩储集层孔隙结构对储集层评价和甜点区优选具有重要意义。综合扫描电镜、气体吸附和核磁共振实验资料,对凉高山组不同岩相的孔隙结构进行表征,研究N_(2)和CO_(2)吸附的孔隙半径分布计算模型,确定不同孔隙半径与横向弛豫时间的转换参数,即表面弛豫速率,实现不同岩相全尺寸孔隙半径表征,同时研究表面弛豫速率与矿物含量的关系。结果表明:表面弛豫速率与石英、斜长石和方解石含量成反比,表面弛豫速率与钾长石、菱铁矿和黏土矿物含量成正比;绿泥石、黄铁矿和菱铁矿属于顺磁性物质,随着顺磁性离子浓度增大,矿物磁化率增大,从而增大表面弛豫速率。The shale reservoirs of Lower Jurassic Lianggaoshan formation in the Sichuan Basin are well⁃developed,with nanoscale pores.These reservoirs are characterized by low porosity,low permeability,diverse pore types,complex pore structures,and a wide range of pore radius distribution.Therefore,accurately evaluating pore structure of shale reservoirs is of great significance for reservoir evaluation and sweet spot prediction.Using the data from scanning electron microscopy(SEM),gas adsorption experiments,and nuclear magnetic reso⁃nance(NMR)experiments,the pore structures of different lithofacies in the Lianggaoshan formation were characterized.The calculation models for pore radius distribution based on N_(2) and CO_(2) adsorption were defined,and the surface relaxation rate,a conversion parameter be⁃tween pore radius and transverse relaxation time,was determined to enable the characterization of full⁃size pore radius across lithofacies.And the relationship between surface relaxation rate and mineral contents was investigated.The results show that the surface relaxation rate is inversely proportional to the contents of quartz,plagioclase,and calcite,and directly proportional to the contents of potassium feldspar,siderite,and clay minerals.Chlorite,pyrite,and siderite are paramagnetic materials;as the concentration of paramagnetic ions increases,the magnetic susceptibility of these minerals increases,thereby enhancing the surface relaxation rate.

关 键 词：四川盆地 凉高山组 孔隙结构 核磁共振测井 气体吸附 孔隙半径分布 表面弛豫速率 

分 类 号：P631[天文地球—地质矿产勘探]