广西融水地区石炭系鹿寨组优质页岩储层特征与成藏模式

Reservoir Characteristics of High-Quality Shale of Carboniferour Luzhai Formation in Rongshui Area,Guangxi

主要以桂融页1井石炭系鹿寨组页岩为研究对象,利用全岩-黏土X衍射、氩离子抛光扫描电镜、核磁共振、现场解吸和地化分析等多种测试手段,结合测录井解释成果,从岩石学、有机地球化学、矿物组成、孔隙类型、储层物性及含气性等方面,系统评价了鹿寨组优质页岩储层特征.结果表明:①石炭系鹿寨组鹿一段优质页岩以黑色碳质页岩和灰黑色灰质页岩为主,主要形成于裂陷海槽沉积环境下的深水相,优质页岩连续厚度大,具备良好的页岩气沉积基础;②页岩有机碳含量高,热演化程度适中,具备良好的生烃基础和生烃能力;③页岩脆性好,孔隙空间发育良好,现场解吸含气性好,具备良好的页岩气储集能力;④页岩分布连续稳定,顶底板条件好,逆断封堵断层有利于页岩气富集保存,具备良好的页岩气保存条件.进一步证实了该地区石炭系鹿寨组具备良好的页岩气富集成藏条件.

This paper mainly takes the shale of Carboniferous Luzhai Formation of Guirongye 1 well as the research object,systematically evaluates the characteristics of high-quality shale reservoir of Luzhai Formation through the aspects of petrology,organic geochemistry,mineral composition,pore type,reservoir physical property and gas bearing property by using a variety of testing methods such as whole rock clay X-ray diffraction,argon ion polishing scanning electron microscope,nuclear magnetic resonance,field desorption and geochemical analysis,combined with logging interpretation results.The analysis results shows:①the high-quality shale in the first member of Luzhai Formation of Carboniferous system is mainly black carbonaceous shale and gray black calcareous shale,which is mainly formed in deep-water facies under the sedimentary environment of rift trough.The highquality shale has a continuous thickness and has a good shale gas sedimentary foundation;②Luzhai shale formation has high organic carbon content,moderate degree of thermal evolution,and has good hydrocarbon generation basis and hydrocarbon generation capacity;③Luzhai shale formation has good brittleness,well developed pore space,good desorption gas bearing property on site and good shale gas storage capacity;④The distribution of shale is continuous and stable,and the conditions of roof and floor are good.Fault reverse plugging is conducive to the enrichment and preservation of shale gas,which has good conditions for shale gas preservation.It is further confirmed that the Carboniferous Luzhai Formation in this area has good conditions for rich shale gas accumulation.