四川盆地长宁地区志留系龙马溪组页岩孔隙特征及发育控制因素

Characteristics of pores and the controlling factors in Longmaxi Formation of Silurian Changning Area,Sichuan Basin

利用四川盆地长宁地区龙马溪组产气层岩芯扫描电镜图像研究泥页岩储层孔隙特征,根据泥页岩成分和孔隙格架矿物,将孔隙分为三大类,并从TOC含量、岩性及矿物成分、热演化程度等方面讨论其对孔隙的影响。认为无机孔隙的形态受格架矿物的形态控制,有机质孔隙的形态受热演化程度控制。相关性分析显示龙马溪组孔隙类型主要为有机质孔隙,影响孔隙的主要因素是有机质含量,其次是热演化程度和矿物含量。从储层特征出发分析了研究区内孔隙类型和孔隙发育的控制因素,为储层基础评价研究提供了思路。

The research observed and analyzed the pore characteristics of Longmaxi Formation mud shale reservoir, by using the Scanning Electron Microscope （SEM） images of the core samples of gas producing zone in the Changning area of Sichuan Basin. According to the shale mineral composition and porosity grid, the pores were divided into 3 categories. It then discussed the controlling factors in porosity development including total organic carbon （TOC） content, lithology and mineral composition, and thermal evolution degree. It concluded that the inorganic pore shape is shaped by mineral framework, while the organic pore shape is controlled by ther- mal evolution degree. The correlation analysis indicated that organic pore is the main type of study area. Of particular importance to po- rosity is organic matter content, which is followed by thermal evolution degree and mineral content. It discussed the types of pore and the controlling factors in pore development, which could help the shale reservoir evaluation.