陆相页岩孔隙类型、特征及油气共聚过程探讨——以辽河坳陷西部凹陷为例  

Pore Types and Characteristics of Continental Shale and Discussion on the Process of Oil and Gas Accumulation:A Case Study of the Western Sag of Liaohe Depression

作　　者：黄潇[1,2] 张金川[1,2] 李晓光[3] 孙睿[1,2] 彭建龙[1,2] 隆帅 

机构地区：[1]中国地质大学能源学院,北京100083 [2]地质资源勘查国家级实验教学示范中心,北京100083 [3]中国石油辽河油田公司勘探开发研究院,辽宁盘锦124010

出　　处：《天然气地球科学》2015年第7期1422-1432,共11页Natural Gas Geoscience

基　　金：国家自然科学基金"辽河坳陷页岩油和页岩气聚集条件及富集机理"(编号:41272167)资助

摘　　要：借助岩心描述、氩离子抛光扫描电镜对以辽河坳陷西部凹陷为代表的陆相页岩中不同尺度储集空间类型、特征进行了研究,并探讨了页岩油气的聚集过程。结果表明,研究层段发育溶蚀孔缝、构造缝等有利于页岩油聚集和运移的大孔径孔洞和裂缝。扫描电镜下,研究层段发育无机矿物孔、有机质孔及微裂缝3种微观孔隙类型,其中低成熟度条件下大孔径有机质孔的形成主要与有机酸的溶蚀改造有关。对微裂缝的研究表明,有机质边缘和内部可以发育多种形态裂缝,而有机质内部生排烃裂缝的大量发育则是陆相低成熟度页岩与南方高成熟度页岩的重要区别。研究区陆相页岩有机质正处于生油气高峰阶段,油气共存,聚集机理较为复杂。吸附态页岩气主要赋存于有机质和黏土矿物内外表面,溶解态页岩气则主要在原油的携带下逐渐在整个页岩段的宏观、微观孔隙中富集,并将油气在页岩层段的聚集过程分为以生物气聚集、油气微观聚集、油气宏观聚集和页岩层段富集为特征的4个阶段。Based on core description, ion beam-scanning electron microscope （FIB-SEM）, pore types and characteristics of different scale of continental shale which is represented by the western sag of Liaohe De- pression were studied,and the accumulation process of shale oil and gas in the pores was discussed. The re- sults show that the development of large pores like dissolution pores and cracks, tectonic cracks helps the accumulation and migration of oil in the study interval. What＇s more, inorganic mineral pore, organic pore and micro-cracks were discovered by FIB-SEM, and the formation of the large organic pores is related to the dissolution of the organic acid in the condition of low maturity. Meanwhile, the results show that a variety of micro-cracks are developed in the edge and internal of the organic matter. The extensive development of organic internal cracks is actually the main difference between low maturity continental shale and southern high maturity marine shale. The continental organic in the study area is in the peak of oil generation with a large number of natural gases,and the oil and gas existed at the same time so that the accumulation mecha- nism is relatively complex. The inner and outer surface of organic and clay plays an important role in the storage of absorbed shale gas, and the dissolved shale gas is mainly stored in the crude oil. The oil-carried gas fills the pores in the shale interval which shares a high oil and gas saturation. Finally, the migration processes are divided into four stages, i. e. , bio-gas accumulation, oil and gas micro accumulation,oil and gas macro accumulation and shale interval accumulation.

关 键 词：陆相页岩 宏观孔隙 微观孔隙 油气共聚 聚集过程 

分 类 号：TE132.3[石油与天然气工程—油气勘探]