AIR HAMMER DRILLING
Precision Air Drilling‘s Air Hammer Division takes our years of experiences with air drilling and compression, combined with durable Halco Rock Tools air hammers to give you a cost effective solution for ‘down the hole’ drilling.
Useful in a wide variety of applications, Air Hammer drilling can decrease drilling times and is more environmentally friendly than other drilling systems.
The advances in Air hammer drilling have in many fields resulted in better holes and in many cases doubled ROP which has given many operators dramatic cost savings. There are many applications for conventional hammers include blast hole drilling, water well and geothermal drilling, mineral exploration, seismic investigation, intermittent sampling and a wide variety of civil engineering and underground mining applications.
Civil engineering applications include piling, site investigation, and ground consolidation and anchoring, post holes, de-watering, earthing rod installation, micro-piling and monitoring ground movement and ground contamination. Underground mining applications include rock bolting, cable anchoring, blasting, cut out raises, communication and ventilation raises, rescue shafts, instrumentation installations and underground service passages. The Air Hammer is now probably the most versatile drilling method available for most applications because it can be used in medium and hard formations enabling them to be used in conditions previously exclusive to rotary, drifter and coring techniques.
Field evidence has demonstrated air drilling can be significantly improved with hammer bits in terms of Rate of Penetration (ROP), hole geometry, cost per foot, etc.
Hammer drilling has long been recognized to have the potential of drilling faster than conventional rotary drill, especially in some hard formations such as granite, sandstone, limestone, and dolomite.
With the same Weight on Bit (WOB) and Rotation per Minute (RPM), it has been demonstrated that percussive-rotary method can be up to 7 times faster than the conventional rotary method. Air hammers have been used to drill gas wells all over the world since 1950s. Air hammers have been used on numerous wells in different fields through the world. In many cases the number of days spent drilling with the use and air and hammers have been cut in half. That translates to a corresponding cost per foot reduction of 50% by using air with hammers compared with conventional rotary and mud drilling.
Another significant advantage of air hammer drilling is less well deviation. In some fields we have worked there were some wells drilled into a high dipped formation, such as 45 degrees. In these fields less than 1 degree deviation was achieved for most wells, compared to 5 degree deviation with use of roller cones bits.
Hard rock drilling is not the only application for the use of hammers. Overburden Systems in Soft soil is normally drilled with augers or by the rotary method. Hammers have adapted to soft conditions by being able to drill and case the hole simultaneously using an eccentric bit which can be withdrawn on completion of the bore hole, Leaving the casing in situ, thus preventing hole collapse. This id achieved by enabling the down the hole drill string and casing to be lowered simultaneously. A down the hole hammer is used to which is fitted a driver and eccentric bit.
Other attractions of hammer drilling include lower requirement for WOB, less contact time between bit and rock, longer bit life, and the generation of larger cuttings. Some additional applications of percussion drilling have been looked at recently, such as using hammers as steady seismic signals to estimate rock properties, or using hammers with a steerable drilling device.