松辽盆地古龙页岩成岩—孔隙演化  

Diagenesis-pore evolution for Gulong shale in Songliao Basin

作　　者：邵红梅[1,2] 高波 潘会芳[1,2] 陈国龙 李玲玲[1,2] SHAO Hongmei;GAO Bo;PAN Huifang;CHEN Guolong;LI Lingling(Exploration and Development Research Institute of Daqing Oilfield Co Ltd,Daqing 163712,China;Heilongjiang Provincial Key Laboratory of Continental Shale Oil,Daqing 163712,China)

机构地区：[1]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712 [2]黑龙江省陆相页岩油重点实验室,黑龙江大庆163712

出　　处：《大庆石油地质与开发》2021年第5期56-67,共12页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家科技重大专项“松辽盆地北部致密油资源潜力、甜点区预测与关键技术应用”(2016ZX05046-006-002)。

摘　　要：为深化松辽盆地古龙页岩储层成岩—孔隙演化规律的认识,创新页岩微—纳米孔隙成因分析技术,结合岩石薄片鉴定、X衍射全岩矿物、扫描电镜等分析方法,探讨古龙页岩成岩演化规律及其作用下的孔隙成因。结果表明:古龙页岩为黏土质长英页岩,纯页岩厚度比例达95%以上,由粒径小于3.9μm的泥级碎屑组成,主要矿物成分为石英、黏土矿物、长石,黏土矿物类型以伊利石、伊/蒙混层为主。松辽盆地古龙页岩经历了压实、胶结、交代、黏土矿物转化、生烃、溶蚀等成岩作用,其中胶结物类型包括硅质、黏土矿物、碳酸盐和黄铁矿。压实作用、胶结作用影响了粒间孔等原生孔隙的保存和演化。黏土矿物演化和有机质热演化利于优质储层发育。古龙页岩主要处于中成岩A期—B期,有机质在生烃过程中生成大量纳米级有机孔,排出的酸性流体溶解长石等不稳定矿物,为蒙脱石向伊利石转化提供K+,形成黏土矿物晶间孔、溶蚀孔,黏土矿物、有机质演化过程中,形成大量页理缝,有效改善了页岩的储集能力。In order to deepen the understandings of diagenesis and pore evolution laws of Qingshankou Formation shale reservoirs in North Songliao Basin,the analysis technique of shale micro-nano pore genesis is innovated.Combined with thin-section identification,whole rock mineral XRD,and SEM analysis,the diagenesis types and pore genesis of Gulong shale are explored.The studies show that Gulong shale is pure continental shale,with thickness more than 95%,and composed of mud-grade debris with particle size less than 3.9μm,i.e.being clayey felsic shale.The host mineral components are quartz,clay minerals and feldspar.Clay minerals are mainly illite and illite/smectite mixed layers.The shale of Qingshankou Formation in Songliao Basin has undergone diagenesis of compaction,cementation,metasomatism,clay mineral transformation,hydrocarbon generation and dissolution,with cements including siliceous,carbonate and pyrite.Evolution of inorganic minerals and thermal maturation of organic matter are beneficial to the development of high-quality reservoirs.A large number of nano-sized organic pores are formed in the process of hydrocarbon generation from organic matter,and the discharged acid fluid dissolves unstable minerals such as feldspar and provides K+for illite,with intercrystalline pores of clay minerals and dissolved pores formed.Lamellation fractures are formed during transformation of clay minerals and thermal evolution of organic matters,and effectively improve accumulating capacity of the shale.Compaction and cementation affected the preservation and evolution of primary pores such as intergranular pores.

关 键 词：古龙页岩 松辽盆地 黏土矿物 成岩作用 孔隙演化 页理缝 

分 类 号：P618.130.21[天文地球—矿床学]