论文部分内容阅读
成熟度处于“生油窗”范围的页岩含有一定数量的残余可溶有机质,其对页岩储层特性的表征具有重要影响。对取自四川盆地西北缘的2件上二叠统大隆组页岩,采用二氯甲烷与三氯甲烷进行了抽提处理,对去除可溶有机质前、后的页岩开展了有机地球化学、矿物组成、孔隙结构(比表面积、孔容)等储层特性对比研究。结果表明:抽提后样品的TOC、S1、S2、IH等热解参数呈现降低的趋势,但其矿物组分没有变化,保持了页岩原有孔隙结构特征。可溶有机质占据一定孔隙空间,阻碍了孔隙间的连通性。抽提后的页岩测定的比表面积和孔容变大。页岩样品中残余可溶有机质主要分布于微孔及较小的介孔中,并受成熟度水平的制约。对于低成熟度页岩样品,可溶有机质主要赋存于小于5nm有机质孔隙中。对于中等成熟度页岩样品,微孔及小于20nm介孔成为主要的储集空间。
Shale with maturity within the “oil window” range contains a certain amount of residual soluble organic matter, which has a significant impact on characterization of shale reservoir properties. Two shales from the Upper Permian Dalong Formation in the northwestern margin of the Sichuan Basin were extracted with dichloromethane and trichloromethane, and organic geochemistry was performed on the shale before and after the removal of soluble organic matter , Mineral composition, pore structure (specific surface area, pore volume) and other reservoir characteristics of comparative study. The results showed that the TOC, S1, S2, IH and other pyrolysis parameters showed a decreasing trend after extraction, but their mineral components did not change, maintaining the original pore structure of shale. Soluble organic matter occupies a certain pore space, hindered the connectivity between the pores. The specific surface area and pore volume measured after the extraction of shale became large. Residual soluble organic matter in shale samples is mainly distributed in micropores and smaller mesopores, and is controlled by the level of maturity. For low-maturity shale samples, soluble organic matter mainly occurs in pores less than 5 nm in organic matter. For medium maturity shale samples, micropores and mesopores smaller than 20 nm are the main reservoir space.