Bit water hole is an important organ in drilling to make full use of bit hydraulic power, to make high-speed liquid directly shoot to the bottom of the well, to fully remove cuttings at the bottom of the well, and to improve drilling efficiency. It is mainly composed of nozzle, circlip and sealing ring.
The bit suitable for jet drilling is jet bit. Its structure shall consider the following aspects:
The flow passage of the inner cavity of the bit body should make the mud flow with less resistance;
The nozzle shape should have good jet characteristics (large flow coefficient, long isokinetic core);
The nozzle can be selected or replaced according to the hydraulic design requirements;
The arrangement of water holes (jet direction, water hole position and quantity) shall be conducive to the removal of cuttings.