Leak detection in circulated fluid systems for heating subsurface formations

• US 8,631,866 B2
• Filed: 04/08/2011
• Issued: 01/21/2014
• Est. Priority Date: 04/09/2010
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Nguyen, Scott Vinh
• Primary Examiner(s): SUCHFIELD, GEORGE A
• Application Number:
  US13/083,246
• Publication Number:
  US 20110247808A1
• Time in Patent Office: 1,019 Days
• Field of Search: None
• US Class Current: 166/250.08
• CPC Class Codes: E21B 36/00 Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones
• CPC Class Codes: E21B 36/04 using electrical heaters
• CPC Class Codes: E21B 43/24 using heat, e.g. steam injection
• CPC Class Codes: E21B 43/2401 by means of electricity
• CPC Class Codes: E21B 43/305 comprising at least one inclined or horizontal well
• CPC Class Codes: E21B 47/113 using electrical indications; using light radiations
• CPC Class Codes: E21B 47/117 Detecting leaks, e.g. from tubing, by pressure testing

Abstract

A method of treating a subsurface formation includes circulating at least one molten salt through at least one conduit of a conduit-in-conduit heater located in the formation to heat hydrocarbons in the formation to at least a mobilization temperature of the hydrocarbons. At least some of the hydrocarbons are produced from the formation. An electrical resistance of at least one of the conduits of the conduit-in-conduit heater is assessed to assess a presence of a leak in at least one of the conduits.

Claims

1. A method of treating a subsurface formation, comprising:

circulating at least one molten salt through at least one conduit of a conduit-in-conduit heater located in the formation to heat hydrocarbons in the formation to at least a mobilization temperature of the hydrocarbons;

producing at least some of the hydrocarbons from the formation;

assessing an electrical resistance of at least one of the conduits of the conduit-in-conduit heater; and

assessing a presence of a leak in at least one of the conduits based on the assessed resistance.

2. The method of claim 1, wherein the leak comprises a breach in the conduit wall.

3. The method of claim 1, further comprising continuously assessing the electrical resistance to assess the presence of a leak.

4. The method of claim 1, further comprising intermittently assessing the electrical resistance to assess the presence of a leak.

5. The method of claim 1, further comprising assessing the electrical resistance to assess the presence of two or more leaks in at least one of the conduits.

6. The method of claim 1, further comprising assessing a depth below the surface of the leak.

7. The method of claim 1, further comprising assessing a depth below the surface of the leak based on a linear relationship between depth and electrical resistance.