黔北地区牛蹄塘组过成熟页岩有机质孔隙发育特征及影响因素  

Organic matter pore and its influencing factors in over-mature shale of the Niutitang Formation,northern Guizhou area

作　　者：周菲 赵凌云 吴章利 夏鹏 王科 宁诗坦 施辉菊 ZHOU Fei;ZHAO Lingyun;WU Zhangli;XIA Peng;WANG Ke;NING Shitan;SHI Huju(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;Guizhou Academy of Petroleum Erploration and Development Engineering,Guiyang 550081,China;Key Laboratory of Unconventional Natural Gas Evaluation and Development in Compler Tectonic Areas,Ministry of Natural Resources,Guiyang550081,China;Key Laboratory of Ministry of Education for Geological Resources and Environment,Guiyang 550025,China;National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum,Beijing 102249,China)

机构地区：[1]贵州大学资源与环境工程学院,贵州贵阳550025 [2]贵州省油气勘查开发工程研究院,贵州贵阳550081 [3]复杂构造区非常规天然气评价与开发自然资源部重点实验室,贵州贵阳550081 [4]喀斯特地质资源与环境教育部重点实验室,贵州贵阳550025 [5]油气资源与工程全国重点实验室,中国石油大学(北京),北京102249

出　　处：《天然气地球科学》2025年第2期240-256,共17页Natural Gas Geoscience

基　　金：贵州省地质勘查资金项目(编号:52000021MGQSE7S7K6PRP);国家自然科学基金项目(编号:42002166,42162016)联合资助。

摘　　要：有机质类型及其孔隙发育特征是页岩气评价的重要内容,决定了页岩生烃能力和页岩气分布特征,但对于黔北地区牛蹄塘组黑色页岩有机质类型及其孔隙发育特征的认识尚不深入,有机质孔隙发育影响因素尚不明确。通过对牛蹄塘组富有机质页岩进行矿物组成和有机地球化学特征分析,利用场发射扫描电镜(FE-SEM)定性分析有机质的赋存状态和孔隙结构,采用低温气体(CO_(2)/N_(2))吸附实验、小角中子散射实验定量分析页岩和干酪根孔隙结构特征,探究该页岩孔隙发育特征及其影响因素。结果表明:①牛蹄塘组页岩主要矿物成分为石英和黏土矿物,有机质显微组分以腐泥组为主,干酪根以I型为主,处于过成熟演化阶段;②页岩孔隙包括粒间孔、粒内孔和有机孔,不同赋存状态的有机质孔隙结构特征差异明显;③有机质孔隙发育受总有机碳含量(TOC)和热成熟度(R_(o))的影响,随TOC含量的增加,不同尺寸有机质孔隙发育有所差异,微孔和介孔比表面积先降低后升高,宏孔比表面积降低,宏孔和介孔体积降低,微孔体积变化小。在RO值为2.29%~5.06%时,随着R_(o)值的增加,有机质微孔和介孔的比表面积和体积逐渐减少,宏孔体积增大;④矿物类型对不同尺寸有机孔影响不一致,微孔随石英含量增加而升高,微孔和介孔随黄铁矿含量增加而降低,介孔和宏孔随黏土矿物含量增加而升高。研究结果对深入理解黔北地区牛蹄塘组页岩孔隙发育特征具有参考价值。The type of organic matter and its pore development characteristics are crucial components in the evaluation of shale gas,as they determine both the hydrocarbon generation capacity and the distribution characteristics.However,the understanding of the organic matter types and its pore development characteristics of black shale in Niutitang Formation in northern Guizhou remains limited,and the factors influencing organic matter pore development are not yet well understood.To address this,the basic mineral composition and organic geochemical characteristics of the organic-rich shale in the Niutitang Formation were first analyzed.Next,the field emission scanning electron microscope(FE-SEM)was used to qualitatively analyze the occurrence state and pore structure of organic matter,and then the low temperature gas(CO_(2)/N_(2),)adsorption experiment and small angle neutron scattering experiment were used to quantitatively analyze the pore structure characteristics of shale and kerogen,so as to explore the pore development characteristics and influencing factors of the Niutitang Formation shale.The results show that:(1)The main mineral components of the Niutitang Formation shale are quartz and clay minerals.The macerals of organic matter are mainly sapropel group,and the kerogen is mainly type I,which is in the over-mature evolution stage.(2)Shale pores include intergranular pores,intragranular pores and organic matter pores,and the pore structure characteristics of organic matter in different occurrence states are obviously different.(3)With the increase of TOC content,the development of different organic matter pore types changes.The specific surface area of micropores and mesopores decreases first and then increases,while the specific surface area of macropores decreases.The volume of macropores and mesopores decreases,and the contribution of micropore volume is small.When R_(o),is 2.29%to 5.06%,with the increase of R_(o),the specific surface area and volume of micropores and mesopores of organic matter gradually decr

关 键 词：黔北地区 牛蹄塘组 过成熟页岩 有机质 孔隙结构 

分 类 号：TE122.1[石油与天然气工程—油气勘探]