DRILLING STRING Russian patent published in 2008 - IPC E21B21/00 

FIELD: drilling equipment, particularly drilling strings for rotary all-purpose well drilling with direct and reverse flushing.

SUBSTANCE: drilling string comprises boring pump, compressor with delivery hoses and with check valves, as well as double kelly, drilling pipe and sub having connection nipple. The connection nipple is communicated with inner pipe and with shutoff means. Drilling string comprises sludge line. Delivery hose of compressor has joint unit and is suspended to swivel in alignment with connection nipple axis. Sludge line is connected to delivery line of boring pump and is provided with shutoff means. Inner pipe is communicated with connection nipple through outer pipe.

EFFECT: increased well drilling efficiency due to optimized flushing mode and system.

2 cl, 1 dwg