APPLICATION OF REPLACED AND COMPACTED DRILLING TECHNOLOGY OF LONG HELIX DRILLER IN SAND COBBLE LAYER IN BEIJING

The usage of long helix driller in sand cobble layer is proved difficult and even impossible and need other methods to complete in some cases because the cobble is higher in density and bigger in diameter. With the improved driller and drilling technology, the compacted drilling technology discussed here is a testified successful way for sand cobble layer, the problem is solved, the efficiency is improved and the cost is saved.