Downhole Gas Influx Detection

• US 20090078411A1
• Filed: 09/20/2007
• Published: 03/26/2009
• Est. Priority Date: 09/20/2007
• Status: Abandoned Application

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Kenison, Michael H., Kane, Moussa
• Application Number:
  US11/858,527
• Publication Number:
  US 20090078411A1
• Time in Patent Office: Days
• US Class Current: 166/250.30
• CPC Class Codes: E21B 47/107 using acoustic means

Abstract

A technique enables determination of gas influx in a fluid handling system. A tubing is provided for conducting fluid flow therethrough. Pressure signals are transmitted through the fluid in the tubing. Parameters of the pressure signal, e.g. time and/or attenuation, are measured at a first location and a second location along the tubing. Parameter data is evaluated to determine the occurrence of changes indicative of gas influx into the tubing.

Claims

1. A method of determining gas influx, comprising:

deploying a tubing in a wellbore;

transmitting a pressure signal downhole through a fluid in the tubing;

measuring a time delay and an attenuation of the pressure signal at a downhole location; and

outputting data, corresponding to the time delay and the attenuation, to a control system for determining the occurrence of gas influx into the tubing.

2. The method as recited in claim 1, wherein deploying comprises deploying a coiled tubing in the wellbore.

3. The method as recited in claim 1, wherein transmitting comprises utilizing a valve to create the pressure signal.

4. The method as recited in claim 1, wherein transmitting comprises transmitting a pulse signal.

5. The method as recited in claim 1, wherein transmitting comprises transmitting a continuous wave signal.

6. The method as recited in claim 1, further comprising utilizing the control system to calculate a gas fraction resulting from gas influx.

7. The method as recited in claim 1, further comprising utilizing the control system to compare the time delay and attenuation of a plurality of sequential pressure signals to determine changes indicative of gas influx.

8. The method as recited in claim 1, further comprising utilizing the control system to compare the time delay and attenuation to a baseline time delay and attenuation to determine the occurrence of gas influx.

9. A system, comprising:

a tubing deployed in a wellbore;

a pressure modulation device to transmit a pressure signal downhole through the tubing;

an uphole sensor to detect time and pressure of the pressure signal;

a downhole sensor to detect time and pressure of the pressure signal; and

a control system coupled to the uphole sensor and the downhole sensor to measure a time delay of the pressure signal as it moves from the uphole sensor to the downhole sensor, the control system being able to use the time delay to determine a gas influx in the tubing.

10. The system as recited in claim 9, wherein the tubing comprises coiled tubing.

11. The system as recited in claim 9, wherein the pressure modulation device comprises a valve.

12. The system as recited in claim 9, wherein the pressure modulation device is used to transmit a pulse signal.

13. The system as recited in claim 9, wherein the pressure modulation device is used to transmit a continuous wave signal.

14. The system as recited in claim 9, wherein the control system is operated to determine an attenuation of the pressure signal.

15. A method, comprising:

transmitting a pressure signal along a fluid disposed in a tubing; and

determining whether an influx of gas into a liquid has occurred within the tubing by measuring at least one of a speed change and an attenuation of the pressure signal.

16. The method as recited in claim 15, further comprising deploying the tubing in a wellbore.

17. The method as recited in claim 16, further comprising using the tubing for a cleanout procedure.

18. The method as recited in claim 16, wherein determining comprises measuring the pressure and time of the pressure signal at an uphole position and at a downhole position.

19. The method as recited in claim 18, further comprising outputting data obtained at the uphole position and the downhole position to a processor-based control system.

20. A method, comprising:

deploying a coiled tubing string downhole for a well operation;

transmitting a pressure signal along an interior of the coiled tubing;

measuring the length of time required for the pressure signal to travel between two locations along the coiled tubing; and

determining whether a gas has mixed with liquid in the coiled tubing based in the pressure signal travel time between the two locations.

21. The method as recited in claim 20, wherein transmitting comprises transmitting a pulse signal.

22. The method as recited in claim 20, wherein transmitting comprises transmitting a continuous wave signal.

23. The method as recited in claim 20, wherein transmitting comprises transmitting the pressure signal from an uphole location to a downhole location.

24. The method as recited in claim 20, wherein measuring further comprises measuring an attenuation of the pressure signal.

25. The method as recited in claim 24, wherein determining comprises processing time and attenuation data on a processor-based control system.