Fuel cell apparatus and method for downhole power systems

Patent metadata

Field	Value
Publication number	US-2016201436-A1
Application number	US-201615078186-A
Country	US
Kind code	A1
Filing date	Mar 23, 2016
Priority date	May 11, 2005
Publication date	Jul 14, 2016
Grant date	—

Abstract

A rechargeable power system comprising: a drill string configured to operate in a well bore, the drill string comprising: a fuel cell system; a generator in electrical communication with the fuel cell system; a turbine, configured to rotate due to an impingement of drilling mud on one or more turbine blades, the turbine in operable communication with the generator; and where the fuel cell system is configured to provide power at least when drilling mud is not circulating in the well bore, and further configured to be recharged by the generator when drilling mud is circulating in the well bore. A method for operating a rechargeable downhole fuel cell. The method comprises: monitoring a fluid supply pressure; determining whether the fluid supply pressure is below a threshold value; and stopping a fuel cell discharge if the fluid supply pressure is below the threshold value.

First claim

What is claimed is:

1 . A method for generating electricity in a drill string disposed within a wellbore, wherein the drill string comprises a turbine, a generator, and a fuel cell system, the method comprising:
(i) generating electricity using the fuel cell system, wherein the fuel cell system generates electricity by producing an electrochemical reaction between hydrogen and oxygen within a fuel cell stack; (ii) retaining water produced by the electrochemical reaction within the fuel cell stack; (iii) stopping the electrochemical reaction within the fuel cell stack; (iv) circulating drilling mud through the wellbore; (v) generating electricity using the generator, the turbine, and the circulating drilling mud; and (vi) generating hydrogen and oxygen within the fuel cell stack by using the electricity generated in process (v) to electrolyze the water produced in process (i) and retained in process (ii).

2 . The method of claim 1 , further comprising:
drilling the wellbore while the drilling mud is circulating in process (iv).

3 . The method of claim 1 , further comprising:
(vii) stopping the electrolysis within the fuel cell stack; (viii) generating electricity using the fuel cell system, wherein the fuel cell system generates electricity by producing an electrochemical reaction between the hydrogen and the oxygen generated by the electrolysis in process (vi).

4 . The method of claim 3 , wherein process (viii) is performed while circulation of the wellbore mud has stopped.

5 . The method of claim 1 , wherein the fuel cell stack comprises:
a first electrode; a second electrode; a proton exchange membrane located between the first electrode and the second electrode; and at least one water storage medium.

6 . The method of claim 5 ,
wherein, in process (i), the first electrode acts as an anode and the second electrode acts as a cathode; and wherein, in process (vi), the first electrode acts as a cathode and the second electrode acts as an anode.

7 . The method of claim 6 , wherein the at least one water storage medium is located between the proton exchange membrane and the second electrode.

8 . A method for operating a rechargeable downhole fuel cell, the method comprising:
monitoring a fluid supply pressure; determining whether the fluid supply pressure is below a threshold value; stopping a fuel cell discharge if the fluid supply pressure is below the threshold value.

9 . The method of claim 8 , wherein the fluid is hydrogen, and the threshold value is a first threshold value.

10 . The method of claim 8 , wherein the fluid is oxygen, and the threshold value is a second threshold value.

11 . The method of claim 8 , further comprising:
monitoring a second fluid supply pressure; determining whether the first fluid supply pressure and the second fluid supply pressure are in proper proportion to each other; issuing an improper pressure proportion warning if the first fluid supply pressure and the second fluid supply pressure are not in proper proportion to each other.

12 . The method of claim 11 , wherein the first fluid is hydrogen and the second fluid is oxygen.

13 . A method for operating a rechargeable downhole fuel cell, the method comprising:
monitoring a fluid supply pressure; determining whether the fluid supply pressure is above a threshold value; stopping a fuel cell recharge if the fluid supply pressure is above the threshold value.

14 . The method of claim 13 , wherein the fluid is hydrogen, and the threshold value is a third threshold value.

15 . The method of claim 13 , wherein the fluid is oxygen, and the threshold value is a fourth threshold value.

16 . The method of claim 14 , further comprising:
monitoring a second fluid supply pressure; determining whether the first fluid supply pressure and the second fluid supply pressure are in proper proportion to each other; issuing an improper pressure proportion warning if the first fluid supply pressure and the second fluid supply pressure are not in proper proportion to each other.

17 . The method of claim 16 , wherein the first fluid is hydrogen and the second fluid is oxygen.

18 . A method for operating a rechargeable downhole fuel cell, the method comprising:
(i) monitoring at least one of voltage or current at a fuel cell stack; (ii) comparing the at least one of voltage or current to a threshold; and (iii) stopping at least one operation of the fuel cell stack based on the comparison.

19 . The method of claim 18 ,
wherein process (i) comprises monitoring voltage at the fuel cell stack; wherein process (ii) comprises determining whether the voltage is below a first voltage threshold for a given current; and wherein process (iii) comprises stopping a fuel cell discharge if the voltage is below the first voltage threshold.

20 . The method of claim 19 , wherein the first voltage threshold is a first voltage threshold for a given discharging current.

21 . The method of claim 19 , wherein the first voltage threshold is a first voltage threshold for a given power discharge.

22 . The method of claim 18 ,
wherein process (i) comprises monitoring a supply voltage at a fuel cell stack; wherein process (ii) comprises determining whether the voltage is above a second voltage threshold for a given charging current; and wherein process (iii) comprises stopping a fuel cell recharge if the voltage is above the second voltage threshold for a given charging current.

23 . The method of claim 18 ,
wherein process (i) comprises monitoring a discharge current at a fuel cell stack; wherein process (ii) comprises determining whether the discharge current is below a discharge current threshold for a fixed voltage; and wherein process (iii) comprises stopping a fuel cell discharge if the current is below the current threshold for a fixed voltage.

24 . The method of claim 18 ,
wherein process (i) comprises monitoring a current at a fuel cell stack; wherein process (ii) comprises determining whether the current is below a current threshold for a fixed voltage; and wherein process (iii) comprises stopping a fuel cell recharge if the current is below the current threshold for a fixed voltage.

25 . The method of claim 18 ,
wherein process (i) comprises (a) monitoring a current at a fuel cell stack and (b) monitoring a voltage at a fuel cell stack; wherein process (ii) comprises (a) determining whether the current is above a current threshold for a for a fixed power output and (b) determining whether the voltage is below a voltage threshold for a fixed power output; and wherein process (iii) comprises (a) stopping a fuel cell discharge if the current is above the current threshold for a fixed power output and (b) stopping a fuel cell discharge if the voltage is below the voltage threshold for a fixed power output.

26 . The method of claim 18 ,
wherein process (i) comprises (a) monitoring a current at a fuel cell stack and (b) monitoring a voltage at a fuel cell stack; wherein process (ii) comprises (a) determining whether the current is below a current threshold for a fixed recharge power and (b) determining whether the voltage is above a voltage threshold for a fixed recharge power; and wherein process (iii) comprises (a) stopping a fuel cell recharge if the current is below the current threshold for a fixed recharge power and (b) sto

Assignees

• Schlumberger Technology Corp

Inventors

• Zhang Wenlin
• Ramakrishnan Terizhandur S
• Walter Joseph
• Perez Jr Albert

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/241

  with solid or matrix-supported electrolytes · CPC title

• H01M8/0656

  by electrochemical means (H01M8/065 takes precedence) · CPC title

• E21B4/04

  Electric drives (E21B4/12 takes precedence) · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title