Safety systems for electric submersible pumps

1. An electrical submersible pump (ESP) system, comprising:

a motor rotationally coupled to a pump;

a shaft rotationally coupled to the motor;

a lock disk rotatably coupled to the shaft and having at least one lock opening therethrough; and

a rotation lock operable to stop transfer of rotation of the pump to the motor when the ESP is switched off, wherein the rotation lock comprises a solenoid actuated lock pin moveable between an unlocked position and a locked position, and wherein the lock pin is disposed in the at least one lock opening.

2. The system of claim 1 , further comprising a pump discharge valve fluidly coupled to the pump.

3. The system of claim 2 , wherein the pump discharge valve comprises at least one ball type check valve comprising a ball seat and a check ball engageable with the ball seat.

4. The system of claim 2 wherein the pump discharge valve comprises a shuttle valve.

5. The system of claim 1 , further comprising a pump intake control valve fluidly coupled to the pump.

6. The system of claim 5 , wherein the intake control valve comprises a ball type check valve comprising a ball seat and a check ball engageable with the ball seat, the ball type check valve operable to block backflow.

7. The system of claim 5 , wherein the intake control valve comprises a flow bypass, the flow bypass operable to open at a predetermined pressure.

8. The system of claim 5 , wherein the intake control valve comprises:

a first check valve comprising a first ball seat and a first check ball engageable with the first ball seat, the first check valve operable to block backflow; and

a second check valve comprising a second ball seat and a second check ball engageable with the second ball seat, the second check valve operable to block backflow from an annular space between the ESP and a well tube.

9. The system of claim 1 , wherein in the unlocked position, the lock pin is lifted out of the at least one lock opening.

10. The system of claim 1 , wherein a solenoid is energized to move the lock pin into the unlocked position.

11. The system of claim 1 , further comprising a pump discharge valve operable to stop backflow and forward flow through the pump when the ESP is switched off, wherein the pump discharge valve comprises:

at least one first magnet disposed on the shaft; and

a valve disk movable between a first position and a second position and comprising an opening and at least one second magnet,

wherein the shaft is disposed in the opening of the valve disk,

wherein the at least one second magnet interacts with the at least one first magnet, and

wherein rotation of the shaft rotates the at least one first magnet relative to the at least one second magnet, thereby applying a magnetic torque to the valve disk to move the valve disk from the first position to the second position.

12. An electrical submersible pump (ESP) system, comprising:

a motor rotationally coupled to a pump;

a drive shaft rotationally coupled to the motor; and

a pump discharge valve operable to stop backflow and forward flow through the pump when the ESP is switched off, wherein the pump discharge valve comprises:

at least one first magnet disposed on the drive shaft; and

a valve disk movable between a first position and a second position and comprising an opening and at least one second magnet,

wherein the drive shaft is disposed in the opening of the valve disk,

wherein the at least one second magnet interacts with the at least one first magnet, and

wherein rotation of the drive shaft rotates the at least one first magnet relative to the at least one second magnet, thereby applying a magnetic torque to the valve disk to move the valve disk from the first position to the second position.

13. The system of claim 12 , wherein:

the pump discharge valve comprises a housing with one or more flow ports;

the valve disk comprises one or more valve ports, wherein the one or more valve ports are aligned with the one or more flow ports when the valve disk is in the first position.

14. The system of claim 13 , wherein the pump discharge valve further comprises a spring disposed between the housing and the valve disk, wherein the spring biases the valve disk toward the second position.

15. The system of claim 12 , the system further comprising:

a lock disk rotatably coupled to the drive shaft and having at least one lock opening therethrough; and

a rotation lock operable to stop transfer of rotation of the pump to the motor when the ESP is switched off, wherein the rotation lock comprises a solenoid actuated lock pin moveable between an unlocked position and a locked position, and wherein the lock pin is disposed in the at least one lock opening.