以中国石化川南地区五峰组—龙马溪组典型取心井X井为例,基于岩心观察、地化分析、X衍射、物性测试、氩离子抛光—扫描电镜、生烃模拟等多种测试手段,运用“源储耦合”研究思路,分析了取心段作为“源”的属性和作为“储”的属性特征,并探讨“源储耦合”特征。研究表明,川南地区五峰组—龙马溪组底部页岩干酪根类型为腐泥型,富含有机质,处于高—过成熟演化阶段,以生成干气为主;基质孔隙度平均为6.5 %,其中以无机孔为主,无机孔隙类型主要以粒间孔、黏土矿物孔、长石蚀变孔、黄铁矿晶间孔为主;地层温压条件下平均吸附气含量为0.9 m³/t;渗透率平均为0.38×10^-3 μm²,属于超低渗透储层。整体而言,X井在五峰—龙马溪组底部“源”优质,生气量大,现今滞留气量仅为生气量的54.8 %;在储集空间类型方面,以无机孔为主,同时,有机孔大量发育,在赋存方式上以游离气为主;富有机质页岩段发育的纹层增加了储层的渗透性,同时,生物成因的硅质矿物增加了储层的脆性,易于压裂造缝。因此,五峰—龙马溪组底部富有机质页岩段整体为最佳的“源储耦合”层段,是页岩气勘探开发的主要层段和水平井轨迹的关键目标层。

Taking well-X, a typical core well of the Wufeng-Longmaxi Formation in Southern Sichuan Basin, as an example, based on core observation, geochemical analysis, X-ray diffraction, physical properties testing, argon ion polishing SEM, hydrocarbon generation simulation and other testing methods, and by using the research idea of “source-storage coupling”, the properties of the core segment as the “source” and the “storage” respectively are analyzed, and the mechanism of “source-storage coupling” is further discussed. The research results show that the bottom shale in Wufeng-Longmaxi Formation is characterized by sapmpelic kerogen, abundant organic matter, and high degree of thermal evolution, in which dry gas mainly generate. The average porosity of matrix is 6.5 %, mainly are inorganic pores. The inorganic pore types are mainly intergranular pore, clay mineral pore, feldspar alteration pore and pyrite intergranular pore. The average amount of adsorbed gas under formation temperature and pressure conditions is 0.9 m³/t. The average permeability is 0.38×10^-3 μm², which means it belongs to an ultra-low permeability reservoir. Generally speaking, the well-X has sufficient “source” at the bottom of the Wufeng-Longmaxi Formation with large amount of generated gas. The current stagnant gas volume is only about 54.8 % of the amount of generated gas, and the matrix pores are mainly inorganic pores. Meanwhile, organic pores are an important supplement. Free gas is the main body. The development of organic-rich shale section improves the permeability of the reservoir. At the same time, the biogenic siliceous minerals enhance the brittleness of the reservoir and make the reservoir easy to be fractured. Therefore, the organic-rich shale section is the best source-storage coupling interval, and also is the main interval of shale gas exploration and development and the key target layer of a horizontal well.