在普查钻进中大量的工作是在软和中硬岩层里完成的，金刚石钻头在这些岩层中的使用效果常常是不高的。在这样的条件下主要使用正循环，很少为反循环孔底冲洗的机械岩心法钻进。与此同时，还使用其他不用冲洗液的钻进法，即螺旋回转压入法和振动法。而这两种方法只能在25—30米深的钻孔内有效应用，不能钻取基岩岩心。 Much of the work done in census drilling is done in soft and medium hard formations, where the use of diamond bits is often poor. Under such conditions, mainly positive circulation is used, and drilling of the mechanical core method for reverse circulation hole bottoming is seldom performed. In the meantime, other drilling methods that do not use flushing fluid are also used, that is, helical rotary press-in method and vibration method. Both of these methods can only be used effectively in drilling depths of 25-30 meters and can not drill bedrock cores.