1. Increase the drill pressure or reduce the drill pressure has no obvious effect on the drill speed;
2. When drilling footage is significantly slower, or when drilling is significantly elevated;
3. Generally, the pump pressure is slightly elevated or no obvious change; but sometimes high pump pressure, even blocking the nozzle of the drill bits, blocking the circulating passage;
4. The influence of strata changes on the drill speed is little;
5. "Pull the piston" phenomenon in the drill;
6. The bit teeth cannot be effectively eaten into the stratum, showing that torque is smaller or the torque fluctuation range decreases.