地层中存在2 种双重介质：裂缝-孔隙型和裂缝-溶洞型。这2 种双重介质之间存在明显的差别。裂缝-孔隙型双重介质油藏试井曲线上出现“凹子”特征，而裂缝-溶洞型则不出现。裂缝-孔隙型双重介质油藏的产量递减较快，而裂缝-溶洞型双重介质油藏则递减较慢。裂缝-溶洞型双重介质在渗流机制和生产特征上都与单一介质十分类似，因而等价于单一介质。

There are two types of dual porosity media: fracture-pore and fracture-vug, which displays quite different performance. The fracture-pore dual-porosity media are characterized by a “concave” on the well test curve, while the fracture-vug dual-porosity media are characterized by a straight line without a concave. The flow rate of fracture-pore dual-porosity media reservoir declines quite more rapidly than the fracture-vug dual-porosity media. The fracture-vug dual-porosity media reservoir is similar to single porosity reservoir in flow mechanism and production performance, so can be equivalent to single porosity reservoir.