众所周知，单层罐笼提升时，罐笼在井口和井下均水平直装直卸，因此其提升高度即为该提升阶段的阶段高差。那么，双层罐笼提升的装卸载方式及提升高度又如何呢？根据井口和井下各阶段装卸载平台数及罐笼在井口和井下时上下层装卸载顺序，双层罐笼提升时的装卸载方式共有四类型? It is well-known that when a single cage is hoisted, the cage is directly loaded and unloaded at the level of both the well head and the downhole. Therefore, the hoisting height is the stage elevation of the hoisting stage. So, double cage lifting loading and unloading methods and lifting height how? According to the wellhead and downhole stages of loading and unloading platform and the cage in the wellhead and downhole when loading and unloading sequence, double cage lifting loading and unloading methods are four types?