BIT PROTECTION UNIT AND METHOD OF CONTROLLING LOAD FORCE ON BIT DURING DRILLING OPERATION Russian patent published in 2024 - IPC E21B17/06 E21B17/10 E21B21/08 

FIELD: machine building.

SUBSTANCE: bit protection assembly includes an external housing, an external valve sleeve, an internal assembly, and a spring. Internal assembly is made with possibility of selective movement in axial direction relative to the external bushing of the valve and includes an internal bushing of the valve. Inner bushing of the valve has an inoperative position in which one or more holes of the inner bushing of the valve are not communicated with one or more holes of the outer bushing of the valve, and a working position in which one or more holes of the inner valve sleeve are in fluid communication with one or more holes of the outer valve sleeve. Internal assembly is functionally connected to the drill bit and is configured to transfer one or more holes of the internal bushing of the valve to an inoperative position when the load on bit (WOB) force is less than the counter force, and to transfer one or more holes of the internal bushing of the valve to the working position, when the force WOB exceeds the counteracting force. Method of WOB control during drilling operation includes lowering down the borehole of the drill string, ending with the assembly of the bottom of the drill string, which includes a drill bit and the bit protection assembly, bringing the drilling bit into contact with the wellbore bottom, cutting the drilling bit into the wellbore bottom, exposing the bit to the WOB force, increasing the WOB force when the drill bit drills the borehole bottom, moving the internal bushing of the valve from the non-working position to the working one.

EFFECT: higher reliability of bit protection during drilling operations.

20 cl, 16 dwg