Subsea energy storage for well control equipment

1. A method, comprising:

storing electrical energy near a well on a sea floor in an energy storage device, wherein the energy storage device is configured to provide stored electrical energy to operate well control equipment;

storing hydraulic energy near the well on the sea floor in a hydraulic energy storage tank, wherein the hydraulic energy storage tank is configured to provide stored hydraulic energy to operate the well control equipment;

operating a pump from the stored electrical energy to generate the stored hydraulic energy; and

activating the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy, wherein the step of activating the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy comprises activating the well control equipment for a first duration of time with the stored electrical energy and activating the well control equipment for a second duration of time with the stored hydraulic energy.

2. The method of claim 1 , wherein the step of activating the well control equipment comprises activating a shear ram, and wherein activating the shear ram comprises:

activating the shear ram with the stored electrical energy to move the shear ram a first distance; and

activating the shear ram with the stored hydraulic energy to move the shear ram a second distance.

3. The method of claim 2 , wherein the first distance is less than the second distance.

4. The method of claim 2 , wherein the first distance is a portion of a path the shear ram traverses before contacting an obstruction.

5. The method of claim 4 , wherein the obstruction is a drill pipe.

6. The method of claim 1 , further comprising:

storing hydraulic medium at ambient-pressure near the well on the sea floor; and

pressurizing the hydraulic medium with the pump powered by the stored electrical energy.

7. The method of claim 6 , further comprising receiving ambient-pressure hydraulic medium from a remotely-operated vehicle (ROV).

8. The method of claim 1 , further comprising:

receiving pressurized hydraulic medium from a remotely-operated vehicle (ROV); and

operating the pump as a generator from the received pressurized hydraulic medium to recharge the stored electrical energy.

9. The method of claim 1 , further comprising returning hydraulic medium to be re-used in the well control equipment.

10. The method of claim 1 , further comprising:

receiving data from a sensor near the well; and

activating the well control equipment based on data received from the sensor.

11. The method of claim 10 , further comprising:

recording data from the sensor for a period of time;

comparing the recorded data to at least one of a predetermined event signature and a historical event signature; and

determining an event has occurred involving the well control equipment based, at least in part, on the step of comparing.

12. An apparatus, comprising:

well control equipment;

a subsea electrical power supply coupled to the well control equipment and configured to provide stored electrical energy to operate the well control equipment;

a hydraulic reservoir configured to provide stored hydraulic energy;

a hydraulic line coupled to the hydraulic reservoir and coupled to the well control equipment, the hydraulic line configured to supply the well control equipment with the stored hydraulic energy; and

a control system configured to operate the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy, wherein the control system is configured to:

operate the well control equipment for a first time period with the stored electrical energy; and

operate the well control equipment for a second time period with the stored hydraulic energy.

13. The apparatus of claim 12 , wherein the control system is configured to operate a shear ram, and wherein the control system is configured to operate the shear ram by performing steps comprising:

operating the subsea electrical power supply to move the shear ram a first distance using the stored electrical energy; and

operating a hydraulic actuator to move the shear ram a second distance using the stored hydraulic energy.

14. The apparatus of claim 12 , further comprising:

a hydraulic valve; and

a hydraulic actuator coupled to the hydraulic valve,

wherein the control system is coupled to the hydraulic actuator and coupled to the subsea electrical power supply, the control system being configured to operate the well control equipment with stored electrical energy from the subsea electrical power supply and with stored hydraulic energy from the hydraulic line.

15. The apparatus of claim 12 , further comprising a sensor coupled to the control system, in which the control system is configured to activate the well control equipment based, at least in part, on data received from the sensor.

16. The apparatus of claim 15 , in which the control system is further configured to:

record data from the sensor for a period of time to obtain recorded data;

compare the recorded data to at least one of a predetermined event signature and a historical event signature; and

determine an event involving the well control equipment has occurred based, at least in part, on the step of comparing.

17. The apparatus of claim 12 , further comprising a subsea pump coupled to the hydraulic line and coupled to the subsea electrical power supply, the subsea pump configured to generate hydraulic pressure in the hydraulic line from the stored electrical energy in the subsea electrical power supply.

18. The apparatus of claim 17 , in which the hydraulic reservoir comprises an ambient-pressure hydraulic reservoir, and in which the subsea pump is configured to pressurize hydraulic medium of the ambient-pressure hydraulic reservoir to operate the well control equipment using the hydraulic line.

19. The apparatus of claim 12 , further comprising a port configured to receive ambient-pressure hydraulic medium from a remotely-operated vehicle.

20. The apparatus of claim 17 , further comprising a port configured to receive pressurized hydraulic medium from a remotely-operated vehicle (ROV), in which the subsea pump is configured to operate as a generator to recharge the subsea electrical power supply from the received pressured hydraulic medium.

21. A method, comprising:

storing electrical energy near a well on a sea floor in an energy storage device, wherein the energy storage device is configured to provide stored electrical energy to operate well control equipment;

storing hydraulic energy near the well on the sea floor in a hydraulic energy storage tank, wherein the hydraulic energy storage tank is configured to provide stored hydraulic energy to operate the well control equipment;

operating a subsea pump from the stored electrical energy to generate the stored hydraulic energy;

activating the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy;

receiving pressurized hydraulic medium from a remotely-operated vehicle (ROV); and

operating the subsea pump as a generator from the received pressurized hydraulic medium to recharge the stored electrical energy.

22. The method of claim 21 , wherein the step of activating the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy comprises activating the well control equipment for a first duration of time with the stored electrical energy and activating the well control equipment for a second duration of time with the stored hydraulic energy.

23. An apparatus, comprising:

well control equipment;

a subsea electrical power supply coupled to the well control equipment and configured to provide stored electrical energy to operate the well control equipment;

a hydraulic reservoir configured to provide stored hydraulic energy;

a hydraulic line coupled to the hydraulic reservoir and coupled to the well control equipment, the hydraulic line configured to supply the well control equipment with the stored hydraulic energy;

a control system configured to operate the well control equipment with a combination of the stored electrical energy and the stored hydraulic energy;

a subsea pump coupled to the hydraulic line and coupled to the subsea electrical power supply, the subsea pump configured to generate hydraulic pressure in the hydraulic line from the stored electrical energy in the subsea electrical power supply; and

a port configured to receive pressurized hydraulic medium from a remotely-operated vehicle (ROV), in which the subsea pump is configured to operate as a generator to recharge the subsea electrical power supply from the received pressured hydraulic medium.

24. The apparatus of claim 23 , wherein the control system is configured to:

operate the well control equipment for a first time period with the stored electrical energy; and

operate the well control equipment for a second time period with the stored hydraulic energy.