摘要
从济阳坳陷古近系 新近系泥岩的研究实例出发 ,分析了泥岩孔隙结构特征及有机质的赋存状态 ,探讨了泥质烃源岩排烃通道与初次运移的关系模式。研究认为泥岩中孔隙小而多 ,喉道窄而细 ,孔喉分选性较好 ,具有较好的连通性 ,微裂 (隙 )缝常见。泥岩中有机质的赋存状态可划分为顺层富集型、分散型和局部富集型等三种不同的种类。泥岩中有机质呈分散型分布时 ,成熟油气通过较粗孔喉系统作为通道进行排烃是初次运移的方式之一。泥岩中有机质呈顺层富集型分布时 ,在有机质富集处 ,岩石结合力较弱 ,加上成熟油气形成的流体压力较高 ,极易产生微裂 (隙 )缝 。
Based on the research of the living examples of argillaceous rock in the Paleogene Neogene in Jiyang depression, both the occurrence of the organic matters and the characteristics of the pore structure are analysed. Then the pattern of the relationship between the expulsion path and the primary migration of hydrocarbon in the rock has been observed. The study shows that the pores are small but numerous, and the throats are narrow and thin in argillaceous rock, in which there is better sorting of pore throats, and a better interconnecting as well, besides, there are microfractures frequently observed there. When the argillaceous rocks containing more organic matter enter maturity stage, they are helpful to form thicker dissolved pores, and may easily produce more microfractures. This does not only favor the formation of abnormal pressure, but can delay the process of compact as well, therefore, which may protect the pore system. The occurrence of the organic matters in argillaceous rock can be classified into three types: the Enrichment Type, the Dispersion Type and the Partial Enrichment Type.(a) The Enrichment Type means that the organic matters are distributed plentifully along the bedding plane in the rock which deposited mainly in the finer clay particle and fewer detrital material (<15%),and are rich in organic matter; (b) The Dispersion Type means that the organic matters are scattered respectively in the rock which deposited in the coarser clay particle and more detrital material (>15%). This type of deposit of organic matters is various in abundance; (c) The Partial Enrichment Type has the properties of both the Enrichment Type and the Dispersion Type. By means of thicker pore throat system it becomes one of the ways through which the mature hydrocarbon can be exported from source rock when the organic matters occurred in Dispersion Type in argillaceous rock.When the organic matters are richer and occurred in the Enrichment Type in argillaceous rock,the binding and cementing of detritus and rock are weaker,besides,the fluid pressures are higher and can easily produce more microfractures. Therefore,they become the major path for primary migration of the mature hydrocarbon.
出处
《沉积学报》
CAS
CSCD
北大核心
2004年第1期169-175,共7页
Acta Sedimentologica Sinica
关键词
泥岩
赋存状态
初次运移
油气形成
济阳坳陷
organic matter occurrence, argillaceousrock,primary migration, Paleogene Neogene,Jiyang depression