Application Limitations and Future Development Directions of Air Hammer Drilling Technology

Air hammers, also called Down-The-Hole hammers, are previously applied in mining industry, civil engineering, hydrology well drilling and have long been considered an effective approach to improve the rate of penetration (ROP) especially in hard formations. The development of air hammers suitable for oil & gas deep well drilling industry in 2000s substantially increase the drilling ROP in hard to mediate hard formations and effectively prevent well deviation in high dip formations. However, its expanding application in oil & gas field also shows that some problems still exist in following operation: drilling casing accessories, drilling in the wet or water formations, drilling in sloughing wellbores. This paper discusses these application limitations, presents the possible resolutions and future development directions which may help to extend the hammer drilling application range and level.