MULTI-START THREAD CONNECTION FOR DOWNHOLE TOOLS
An apparatus for transferring rotary power to a consumer in a wellbore includes a rotary power source positioned along a conveyance device and a drive train connected to the rotary power source. The drive train transfers torque from the rotary power source to a consumer. The drive train includes at least two torque transmitting members connected by a multi-start thread connection.
1 . An apparatus for transferring rotary power to a consumer in a wellbore, comprising:
a conveyance device configured to be disposed in the wellbore;
a rotary power source positioned along the conveyance device, the rotary power source generating a torque; and
a drive train connected to the rotary power source, the drive train transferring the torque from the rotary power source to a consumer, wherein the drive train includes at least two torque transmitting members connected by a multi-start thread connection.
2 . The apparatus of claim 1 , wherein the multi-start thread connection is formed at a pin and box connection between the at least two torque transmitting members.
3 . The apparatus of claim 1 , wherein a number of starts of the multi-start thread connection is selected to increase torque capacity of a connection between the at least two torque transmitting members relative to a single start thread connection.
4 . The apparatus of claim 1 , wherein the rotary power source is a drilling motor.
5 . The apparatus of claim 1 , wherein the consumer is a drill bit.
6 . The apparatus of claim 1 , wherein at least one of the two torque transmitting members is one of: (i) a rotor, (ii) flex shaft, and (iii) a drive shaft.
7 . The apparatus of claim 1 , wherein the conveyance device is a drill string.
8 . The apparatus of claim 1 , wherein the multi-start screw has at least two intertwined helically wound threads.
9 . A method for transferring rotary power to a consumer in a wellbore, comprising:
disposing a conveyance device in the wellbore, the conveyance having a rotary power source generating a torque; and
transferring torque from the rotary power source using a drive train, wherein the drive train includes at least two torque transmitting members connected by a multi-start thread connection.
10 . The method of claim 9 , wherein the multi-start thread connection is formed at a pin and box connection between the at least two torque transmitting members.
11 . The method of claim 9 , wherein a number of starts of the multi-start thread connection increases torque capacity of a connection between the at least two torque transmitting members relative to a single start thread connection.
12 . The method of claim 9 , wherein the rotary power source is a drilling motor, the consumer is a drill bit, and wherein at least one of the two torque transmitting members is one of: (i) a rotor, (ii) flex shaft, and (iii) a drive shaft.
13 . The method of claim 9 , wherein the multi-start screw has at least two intertwined threads.
14 . A system for transferring rotary power to a consumer in a wellbore, comprising:
a drill string conveyed into the wellbore; and
a bottomhole assembly connected to the drill string, the bottomhole assembly including:
a drilling motor energized by a drilling fluid circulated in the wellbore, and
a drive train connected to the rotary power source, the drive train transferring the torque from the rotary power source to a consumer, wherein the drive train includes a multi-start thread formed at a pin and box connection between at least two torque transmitting members.
15 . The system of claim 14 , the at least one of the two torque transmitting members include a rotor, a flex shaft, and a drive shaft interconnected to one another.
16 . The system of claim 14 , wherein the number of starts of the multi-start thread is selected to reduce the transmitted torque to a value lower than the make-up torque.
17 . The system of claim 14 , wherein the multi-start screw has at least two intertwined threads.