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页岩气储层的物性特征是决定页岩气开发方案的重要因素。通过对渝东南下志留统龙马溪组页岩露头岩心的实验测试,研究了渝东南地区页岩气储层的物性特征。结果表明,渝东南龙马溪组页岩地层为层理发育,频散现象明显,但随着层理倾角的逐渐增加,波速整体呈下降趋势;页岩的孔隙度变化范围为1.5%~2.5%,渗透率变化范围为2.5×10-4~1.3×10-3mD,孔径分布以中孔隙为主,大孔隙较少,基本上没有微孔隙,毛管力较大;页岩的石英含量高,黏土含量低,为硬脆性页岩,脆性参数为0.49~0.77,平均为0.58;黏土成分以伊利石为主,含少量绿泥石和伊/蒙混层,不含蒙脱石,膨胀性能弱。研究结果为渝东南地区页岩气储层的开采方式选择、失稳机理分析以及压裂液方案设计提供了依据。
The physical property of shale gas reservoir is an important factor that determines the shale gas development plan. The physical and chemical characteristics of the shale gas reservoirs in the southeastern Chongqing area are studied through the experimental testing of the shale core of the Lower Silurian Longmaxi Formation in the southeastern part of Chongqing. The results show that the shale formation of the Longmaxi Formation in eastern Chongqing is stratified and the frequency dispersion is obvious. However, with the gradual increase of bedding inclination, the wave velocity decreases as a whole; the porosity of shale ranges from 1.5% to 2.5% , The permeability ranged from 2.5 × 10-4 to 1.3 × 10-3mD, the pore size distribution was mainly mesoporosity, the macropores were less, the micropores were basically absent, and the capillary force was larger. The shale had high quartz content and clay Low content of hard and brittle shale, brittleness parameter of 0.49 ~ 0.77, an average of 0.58; clay composition mainly illite, with a small amount of chlorite and Iraqi / mixed layer, does not contain montmorillonite, swelling performance is weak. The results provide the basis for the choice of mining methods, instability mechanism analysis and fracturing fluid scheme design of the shale gas reservoirs in southeastern Chongqing.