Pulsed High-voltage Discharge Technology Applied in Reaming

Abstract

Principle of pulsed high-voltage discharge technology applied in reaming, test device and relative parameter were expounded in the paper. The process of reaming is that liquid-electric effect is produced, according to discharge in the borehole filled with liquid medium, then shock wave exerted on liquid medium around the electrode radially (perpendicular to direction of discharge) is passed to stratum to compact the soil. Device of pulsed high-voltage discharge introduced from Russia was used to do this experiment, which completed reaming work for two boreholes. Using the same capacitance value, discharge was conducted at 1.5m and 2m in each borehole separately under the condition of different voltages. Boreholes’ diameters were enlarged from 150 mm to 302–319 mm with different discharge times. It indicated that pulsed high-voltage discharge technology could compact and enlarge the diameter rapidly. Compared with traditional reaming technology, this new technology can improve the speed of construction and be better for complex formation, especially drilling in wet formation, in which drill pipe sticking, burying drilling, collapsing borehole and other incidents can be avoided. It’s a new environmentally friendly technology with wide application prospect.