松辽盆地白垩系陆相页岩孔隙演化过程研究  

Research into pore evolution in Cretaceous continental shales in the Songliao Basin

作　　者：李灿星 刘冬冬[1,2] 肖磊[1,2] 姜振学 李卓[1,2] 郭靖[1,2] LI Canxing;LIU Dongdong;XIAO Lei;JIANG Zhenxue;LI Zhuo;GUO Jing(State Key Laboratory Petroleum Resources and Prospecting,China University of Petroleum-Beijing,Beijing,102249,China;Unconventional Petroleum Research Institute,China University of Petroleum-Beijing,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)非常规油气科学技术研究院,北京102249

出　　处：《石油科学通报》2021年第2期181-195,共15页Petroleum Science Bulletin

基　　金：国家科技重大专项(2016ZX05034-001)资助。

摘　　要：页岩的孔隙结构决定了页岩储层的储集能力,因此,研究页岩孔隙演化过程对于揭示页岩气富集机理具有重要意义。前人针对海相页岩的孔隙演化过程已经开展了系统的研究工作,但对于陆相页岩的孔隙演化过程研究相对较少。本文以松辽盆地青山口组低成熟陆相页岩(镜质体反射率R_(O)=0.65%)为研究对象,通过热模拟实验,结合气体吸附、高压压汞(mercury intrusion capillary pressure,MICP)、X射线衍射(X-ray diffraction,XRD)等实验数据,对松辽盆地青山口组陆相页岩孔隙结构演化过程进行了系统分析,并建立了陆相页岩孔隙演化模式。结果表明,随着演化程度的升高,页岩孔体积和比表面积经历了先增大后减小再增大的过程,孔隙演化主要受控于有机质生烃和黏土矿物转化。当0.65%<R_(O)≤0.86%时,干酪根缓慢生烃,结合有机酸溶蚀,形成部分有机质孔隙,页岩孔体积和比表面积少量增加;当0.86%<R_(O)≤1.18%时,蒙脱石脱水和新孔隙形成会造成孔体积和比表面积增加,但此阶段干酪根开始大量生油,生成的液态烃和沥青会充填部分原始孔隙,使得页岩孔体积和比表面积减小;当1.18%<R_(O)≤1.86%时,成熟-高成熟阶段干酪根仍在继续生油,但生油速率开始降低,同时干酪根开始热解生气,形成部分气泡孔,且气孔随演化程度增加进一步增大,且该时期I/S(伊蒙混层)中的蒙脱石向伊利石转化,三种作用促使微孔、中孔和宏孔的孔体积和比表面积增加;当R_(O)>2.15%时,干酪根生油停止,生成的液态烃开始裂解生气,形成大量气泡孔,后期气孔进一步增大,出现孔隙融合现象,同时I/S中蒙脱石向伊利石转化,共同导致孔体积和孔比表面积大幅增加。The pore structure of shale determines the storage capacity of shale reservoirs.Therefore,studying the pore evolution process of shale is of great significance in revealing the mechanism of shale gas enrichment.Previous systematic research work has been carried out on the pore evolution process of marine shale,but relatively little research has been done on the pore evolu-tion process of continental shale.This paper takes the low-maturity(R_(O)=0.65%)continental shale of the Qingshankou Formation in the Songliao Basin as the research object.Through thermal simulation experiments,combined with gas adsorption,mercury intrusion capillary pressure(MICP),X-ray diffraction(XRD)and other analysis,the evolution process of the pore structure of the continental shale of the Qingshankou Formation in the Songliao Basin has been investigated.Systematic analysis,has established the pore evolution model of this continental shale.The results show that as the degree of evolution increases,the pore volume and specific surface area of shale undergoes a process of first increasing,then decreasing,and then increasing.The evolution of pores is mainly controlled by organic hydrocarbon generation and clay mineral conversion.When 0.65%<R_(O)≤0.86%,kerogen slowly generates hydrocarbons and combined with organic acid dissolution,some organic pores are formed,shale pore volume and specific surface area increase slightly.When 0.86%<R_(O)≤1.18%,montmorillonite dehydration and new pore formation will occur.This results in an increase in pore volume and specific surface area,but kerogen begins to generate a large amount of oil at this stage,and the generated liquid hydrocarbons and asphalt will fill part of the original pores,making the shale pore volume and specific surface area decrease.When 1.18%<R_(O)≤1.86%,the kerogen at the maturity-high maturity stage continues to generate oil,but the rate of oil generation begins to decrease.At the same time,the kerogen begins to pyrolyze and form some gas bubbles.And the bubbles further increase

关 键 词：松辽盆地 青山口组 页岩 热模拟 孔隙结构 

分 类 号：P618.13[天文地球—矿床学]