渝东南龙马溪组页岩气储层物性特征

 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。

Reservoir Physical Characteristics of Shale Gas in Longmaxi Formation in Southeastern Chongqing

The physical experiments on the shale outcrop core in the Longmaxi formation in southeastern Chongqing show that the Porosity variation is in the range of 1.5%~2.5%, the permeability is in the range of 2.5×10^-4～1.3×10^-3mD; the Shale beddings and the dispersion phenomenon are clearly seen, but their extents gradually increase with the angle of bedding, and the wave velocity decreases. The pore size distribution is changed, with less large pores, basically with no micro pore, and with a large capillary force. The rock quartz content is high, the clay content is relatively low, as typical of the hard brittle shale. At the same time, the clay is dominated by illite, with a small amount of chlorite and illite/smectite mixed layer, not including montmorillonite, the expansion extent is small, the brittle shale parameters are between 0.49～0.77, the average value is 0.58. Test results provide some guidance for the shale mining method selection, the instability mechanism and the fracturing fluid design scheme in the shale gas development in the region.