Fuel cell apparatus and method for downhole power systems

Patent metadata

Field	Value
Publication number	US-10113398-B2
Application number	US-201615078186-A
Country	US
Kind code	B2
Filing date	Mar 23, 2016
Priority date	May 11, 2005
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

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, 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 located between the proton exchange membrane and the second electrode;
(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, 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.

Assignees

• Schlumberger Technology Corp

Inventors

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

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/0656

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

• H01M8/241

  with solid or matrix-supported electrolytes · CPC title

• H01M8/186

  by electrolytic decomposition of the electrolytic solution or the formed water product · CPC title