论文部分内容阅读
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。
By means of core description and argon ion polishing scanning electron microscopy, the types and characteristics of reservoir space at different scales in continental shale represented by the western depression of Liaohe Depression were studied, and the process of shale hydrocarbon accumulation was discussed. The results show that the pores and fractures of the macropores are favorable for the accumulation and migration of shale oil in the study interval. Under scanning electron microscopy, three types of micropores, ie, inorganic mineral pores, organic pores and microcracks were developed in the study interval. The formation of large pore organic matter pores at low maturity was mainly related to the dissolution and modification of organic acids. The study of microcracks shows that a variety of morphological fractures can be developed in the margin and interior of organic matter, while the large-scale development of organic hydrocarbon-derived hydrocarbon fractures is an important difference between continental low-maturity shale and southern high-maturity shale. The organic matter of continental shales in the study area is at the peak stage of hydrocarbon generation and oil and gas coexist, and the aggregation mechanism is rather complicated. The adsorbed shale gas mainly occurs on the inner and outer surfaces of organic matter and clay minerals. The dissolved shale gas is mainly enriched in macroscopic and microscopic pores of the whole shale mainly under the carrier of crude oil, The accumulation process is divided into four phases characterized by biogas accumulation, micro-accumulation of oil and gas, macro-accumulation of oil and gas, and enrichment of shale intervals.