Annulus plugging detection using a pressure transmitter in gas-lift oil production

• US 20050173112A1
• Filed: 02/03/2005
• Published: 08/11/2005
• Est. Priority Date: 02/05/2004
• Status: Abandoned Application

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Kavaklioglu, Kadir, Peluso, Marcos
• Application Number:
  US11/050,637
• Publication Number:
  US 20050173112A1
• Time in Patent Office: Days
• US Class Current: 166/250.10
• CPC Class Codes: E21B 43/122 Gas lift
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure

Abstract

Outer annulus plugging detection is provided for gas-lift oil wells. The outer annulus detection is effected using a pressure transmitter. The pressure transmitter provides an indication of pressure within an outer annulus of the oil well. A statistical parameter related to a plurality of outer annulus pressure readings is used to provide an indication of annulus plugging. Examples of the statistical parameter include mean and standard deviation.

Claims

1. A system for detecting outer annulus plugging in a gas-lift oil well, the system comprising:

a pressure transmitter operably coupleable to the outer annulus of the gas-lift oil well, the pressure transmitter being adapted to provide a signal related to pressure within the outer annulus; and

a controller configured to receive the signal and obtain a plurality of pressure measurements relative to the outer annulus, which measurements are temporally spaced, the controller being configured to calculate a parameter indicative of annulus plugging based on the plurality of pressure measurements.

2. The system of claim 1, wherein the controller is a component of the pressure transmitter.

3. The system of claim 1, wherein the pressure transmitter is adapted to provide a first signal indicative of pressure within the outer annulus, and a second signal indicative of plugging.

4. The system of claim 3, wherein the pressure transmitter communicates over a digital process communication loop.

5. The system of claim 1, wherein the pressure transmitter is powered by a digital process communication loop.

6. The system of claim 1, wherein the pressure transmitter further comprises an analog-to-digital converter providing digital conversions to the controller.

7. The system of claim 1, wherein the pressure transmitter further comprises an analog-to-digital converter providing a high-speed bitstream to the controller.

8. The system of claim 1, wherein the parameter is a statistical parameter.

9. The system of claim 8, wherein the statistical parameter is mean.

10. The system of claim 8, wherein the statistical parameter is standard deviation.

11. The system of claim 8, wherein the statistical parameter is a combination of mean and standard deviation.

12. The system of claim 1, wherein the parameter is calculated using fuzzy logic.

13. The system of claim 1, wherein the parameter is calculated using a neural network.

14. A method of determining whether an outer annulus of a gas-lift oil well is at least partially plugged, the method comprising:

obtaining a plurality of temporally spaced pressure measurements within the outer annulus;

calculating a statistical parameter using the plurality of measurements; and

providing an indication of plugging based upon the statistical parameter.

15. The method of claim 14, wherein the method is performed by a pressure transmitter.

16. The method of claim 14, wherein the statistical parameter is mean.

17. The method of claim 14, wherein the statistical parameter is standard deviation.

18. A gas-lift oil well comprising:

a first pipe having a first pipe wall defining an interior adapted to convey pressurized crude oil;

a second pipe having a second pipe wall defining an inner annulus with the first pipe wall;

an outer shell defining an outer annulus with the second pipe wall; and

means for detecting plugging of the outer annulus.