Experimental Research on High Energy Liquid-jet Hammer in Granite Drilling

Abstract:

Hot dry rock strata usually are of igneous rocks with strong abrasion and poor drillability. Because of the low drilling efficiency of conventional drilling methods, SC-86H high energy liquid-jet hammer was specially developed for hot dry rock strata drilling, and the ground drilling tests were carried out on the prototype. Intact granite with drillability of grade X was taken as simulation strata, the effects of hammer mass, piston stroke and inputting flow rate on the drilling efficiency were studied. The test results show that increasing the hammer mass, piston stroke and inputting flow rate are beneficial to improve the drilling efficiency. The maximum ROP obtained in the tests is 5.19m/h, which is significantly more than that of conventional rotary drilling machines.

Key words:hot dry rock; drilling; drillability; granite; high energy; liquid-jet hammer; rate of penetration