Methods and apparatus for long term monitoring of a hydrocarbon reservoir

• US 6,230,800 B1
• Filed: 07/23/1999
• Issued: 05/15/2001
• Est. Priority Date: 07/23/1999
• Status: Expired due to Term

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Bryant, Ian
• Primary Examiner(s): Tsay, Frank
• Application Number:
  US09/359,780
• Time in Patent Office: 662 Days
• Field of Search: 166/250.01, 166/66, 166/65.1, 166/64, 166/113, 166/254.2, 166/254.1
• US Class Current: 166/250.01
• CPC Class Codes: E21B 33/13 Methods or devices for cementing, for plugging holes, crevices or the like
• CPC Class Codes: E21B 47/017 Protecting measuring instruments
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure

Abstract

The methods and apparatus of the invention include installing sensors in one or more of the many hole sections which are abandoned before the holes are sealed with cement. According to the invention, a sensor array is attached to the cement delivery device which is used to seal a hole which would otherwise be abandoned. The preferred apparatus for cement delivery is a “coiled tubing”. Preferably, the sensor array is passed through the center of the tubing so that it is protected from damage or snagging while being delivered to its deployment position. The coiled tubing may be withdrawn or left in place after the cement is delivered into the hole. When the cement cures, the sensor array is centered in the cement plug which seals the reservoir. According to the invention, the sensor array may be placed in any well which is to be abandoned. Such wells include exploration wells, appraisal wells, delineation wells, collapsed wells, oil wells which develop high levels of gas or water production, and gas wells which develop high levels of water production. In addition, the sensor array may be deployed in an unused portion of a production or injection well. For example, the sensor array may be located in a logging pocket. Similarly, the sensor array may be located in the pilot hole of a horizontal well.

Claims

1. A method for long term monitoring of a hydrocarbon reservoir, comprising:

a) selecting a well bore which is destined to be sealed with cement;

b) delivering a sensor array coupled to a cable through the well bore to a selected location;

c) filling the well bore with cement so that the sensor array is embedded in cement and the well bore is sealed; and

d) using the sensor array to monitor reservoir conditions during the course of hydrocarbon production, wherein

said step of delivering includes releasably attaching the sensor array to a cement delivery device and running-in the cement delivery device to the selected location.

2. A method according to claim 1, wherein:

the well bore to be sealed is selected from the group consisting of exploration wells, appraisal wells, delineation wells, collapsed wells, oil wells which have developed high levels of gas or water production, and gas wells which have developed high levels of water production.

3. A method according to claim 1, wherein:

said step of filling includes pumping cement through the cement delivery device and releasing the sensor array from the delivery device.

4. A method according to claim 1, wherein:

said step or releasably attaching includes disposing the sensor array inside the delivery device.

5. A method according to claim 4, wherein:

said step of filling includes pumping cement through the cement delivery device and releasing the sensor array from the delivery device.

6. A method according to claim 5, further comprising:

e) raising the delivery device while filling so that the delivery device is completely removed from the well bore when filling is completed.

7. A method according to claim 5, further comprising:

e) raising the delivery device while filling so that the sensor array is exposed from the delivery device but a portion of the delivery device remains embedded in the cement.

8. A method according to claim 1, wherein:

said step of delivering includes running the cable outside the tubing of a production well.

9. A method according to claim 1, wherein:

said step of delivering includes running the cable outside the casing of a cased well.

10. A system for long term monitoring of a hydrocarbon reservoir, comprising:

a) a sensor array;

b) a cable coupled to said sensor array;

c) deployment means for deploying said sensor array at a location in a well bore which is destined to be sealed with cement; and

d) cement delivery means for delivering cement to said location so that said sensor array is embedded in cement and the well bore is sealed, wherein

said deployment means includes coupling means for releasably coupling said sensor array to said cement delivery means.

11. A system according to claim 10, wherein:

said coupling means includes means for releasably retaining said sensor array within said cement delivery means.

12. A system according to claim 10, wherein:

said sensor array includes a resistivity sensor.

13. A system according to claim 10, wherein:

said sensor array includes a pressure sensor.

14. A system according to claim 10, wherein:

said sensor array includes a temperature sensor.

15. A system according to claim 11, wherein:

said means for releasably retaining said sensor array within said cement delivery means includes a pump-out plug.