ELECTRO-CHEMICAL SENSOR

• US 20090014325A1
• Filed: 06/03/2005
• Published: 01/15/2009
• Est. Priority Date: 06/09/2004
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Jiang, Li, Jones, Timothy Gareth John
• Granted Patent: US 8,613,843 B2
• Time in Patent Office: Days
• US Class Current: 204/400
• CPC Class Codes: E21B 49/10 using side-wall fluid samplers or testers
• CPC Class Codes: G01N 33/0047 for organic compounds

Abstract

An electro-chemical sensor for methane is described having a catalyst to react methane or other low molecular weight hydrocarbons and a detector to detect the turnover or reaction rate and using such information to determine the concentration of the methane or other low molecular weight species. The sensor is preferably used for measurements in a wellbore.

Claims

1. An electro-chemical sensor comprising

a catalyst for converting one or more species of hydrocarbons gaseous under standard conditions and a detector to measure a signal indicative of the reaction rate or turnover of said methane conversion.

2. The sensor of claim 1 being a sensor to determine the concentration of the species.

3. The sensor of claim 1 comprising

a plurality of activation centers as catalyst to activate hydrocarbons gaseous under standard conditions for a redox reaction,

an electrode in electrical connection to said activations center and

a metering circuit to determine current flowing through the electrode.

4. The sensor of claim 1 wherein the species of hydrocarbons are of the structure C_nH_2n+2 with n being an integer less than or equal to 5.

5. The sensor of claim 1 wherein the species is methane.

6. The sensor of claim 1 wherein the catalyst is immobilized on a surface of the electrode.

7. The sensor of claim 1 wherein the catalyst is immobilized through covalent chemical bonds on a surface of the electrode.

8. The sensor of claim 1 wherein the catalyst is embedded into a porous matrix.

9. The sensor of claim 1 wherein the catalyst is part of a room temperature ionic liquid.

10. The sensor of claim 1 wherein the catalyst is dissolved in an electrolytic solution.

11. The sensor of claim 1 wherein catalyst comprises catalytic compounds with iron, copper or transition metal based catalytic centers.

12. The sensor of claim 1 wherein catalyst is selected from a group comprising, diiron, Fe2(SO4)3, or tri-copper compounds.

13. The sensor of claim 1 wherein the catalysts covered by a gas-permeable membrane.

14. A downhole tool for measuring characteristic parameters of wellbore effluents comprising an electro-chemical sensor in accordance with claim 1.

15. The tool of claim 14 mounted onto a downhole fluid sampling tool.

16. The tool of claim 14 mounted onto a permanently installed part of the wellbore.

17. The tool of claim 14 mounted onto a drill string.