Drilling of 300-350 long horizontal holes in the coal mine at Ibbenbüren for the purpose of methane gas drainage. The owners of the mine, Deutsche Steinkohle, were looking for new and faster drilling technology to replace the traditional roller-cone method. With roller-cone the average penetration rate is 0,03 meter/minute. The roller-cone bit also needs replacement after every 10 to 30 meters. With Wassara W100 the average penetration rate is increased to 0,5 meters/minute with a bit life of 50 meters+. Pneumatic drilling can not be used due to the explosion risk.
Result:
With Wassara W100 the average penetration rate is increased with a factor of 17 and this is not taking into account the extra time needed to change worn out roller-cone bits. The resulting cost savings has convinced Deutsche Steinkohle that Wassara is the technology to go for.
Equipment:
Hammer
Wassara W100
Bit
Wassara 115 mm
Pump
Hauhinco 372 Lpm, 220 bar and 150 kW
Drilling fluid
Clean water, filtered to 50 micron
Drill pipe
1 meter, local design
Rig
Deilmann Haniel
Formation
Sandstone with high quartzite content, 180 MPa compressive strength