鄂尔多斯盆地南部延长组长7段陆相页岩气地层孔隙类型、尺度及成因分析  

ANALYSIS OF PORE TYPES,SIZES AND GENESIS IN CONTINENTAL SHALE GAS RESERVOIR OF CHANG 7 OF YANCHANG FORMATION,ODROS BASIN

作　　者：曹茜[1,2] 周文[1,2] 陈文玲[1,2] 邓虎成[1,2] 闫长辉[1,2] 邓昆[1,2] 

机构地区：[1]成都理工大学能源学院,四川成都610059 [2]成都理工大学"油气藏地质及工程"国家重点实验室,四川成都610059

出　　处：《矿物岩石》2015年第2期90-97,共8页Mineralogy and Petrology

基　　金：国家863计划(2013AA064501);国家十二五重大专项(2011ZX05018002-001)

摘　　要：应用氩离子抛光-场发射环境扫描电子显微镜对其孔隙特征进行描述,统计不同孔隙孔径分布范围,同时结合其样品粘土矿物成分、含量测试实验,分析不同孔隙成因。针对18口取芯井,共399.04m岩心进行样品采集,通过对鄂尔多斯盆地延长组长7段典型陆相页岩储层105块岩石薄片样品及83块铸体薄片样品进行测试分析的结果表明,鄂尔多斯盆地延长组陆相页岩油气地层,有机质演化程度中等,RO在0.6%~1.3%之间,其孔隙类型主要分为基质孔隙和有机质孔隙两大类,其一为基质孔隙,包括有原生晶(粒)内、间孔及晶间隙和次生的晶间溶孔,主要是与蒙脱石转化为I/O混层或伊利石时脱水形成的微孔隙,同时见有少量经过溶蚀孔形成的晶间溶孔;其二为有机质孔隙,主要是在有机质不同演化阶段排烃形成的出油孔和出气孔,及演化到大规模成气阶段的"气孔群"。孔隙尺度统计结果表明,该套陆相页岩油气地层的微孔隙大小主要分布在0.02μm^100μm之间。基质孔隙尺度分布较宽,平均尺度相对较大,微米级孔隙占约23%左右,纳米级孔隙占约77%;有机孔隙尺度相对较小,主要分布在20nm^750nm之间,以纳米级孔隙为主。分析认为鄂尔多斯盆地延长组陆相页岩气地层微孔隙体系的形成与(泥)页岩的成岩演化及有机质的热演化成熟度有关,不同演化阶段形成不同微孔隙类型。The characteristics and genesis of the pores of typical continental shale reservoir of Chang 7 of the Yanchang Formation in Ordos Basin were investigated by using Argon ion polishing,SEM images and clay mineral composition and content testing. More than 105 blocks samples were collected from the core of 399.04 m from 18 wells,and 83 pieces of casting thin section were made. The results show that the evolution degree of organic matter is medium, and the value of Ro is between 0. 6% and 1.3%. One of the main pore types is the matrix pore,including intracrystal,intra-particle, inter-crystal primary pores and ＇inter-crystal dissolution secondary pores. Most of the matrix pores are the micropores formed in the dehydration process of montmorillonite translated into I/O mixed layer or illite,and some inter-crystal dissolution are produced in the organic acid corrosion process. The Other type is organic pore, which is mainly the oil/gas outlet pore formed in the organic hydrocarbon expulsion of different evolution stages, and the ＂ gas pores＂ in the large-scale gas generation stage. By adding up the pore sizes, the results show that the average scale of the matrix pores is relatively large and the scales mainly range from 0. 02 him to 100 btm. Among the matrix pores,micropores accounted for about 23% and the nanopores accounted for approximately 77%. While most of the organic pores are nanopores, and the scale of organic pores is between 20 nm and750 nm. Comprehensive analysis study revealed that the formation of micropores hosted in continental shale gas reservoir of Yanchang Formation in Ordos basin was related with the （mud） shale＇s diagenetic evolution and with the organic matter＇s thermal maturity, resulted in different micropore types in different evolution stages.

关 键 词：陆相页岩地层 孔隙类型 孔隙尺度 成因分析 鄂尔多斯盆地 延长组 

分 类 号：TE122.116[石油与天然气工程—油气勘探]