Deployable mandrel for downhole measurements
View Patent ↗The disclosed apparatus comprises a phase fraction meter and a compliant mandrel deployable within a production pipe, and may further comprise a flow velocity meter. The mandrel allows the determination of the phase fraction for a fluid comprising three phases by providing an additional cross sectional compliance within the conduit, thereby allowing the density of the fluid to be determined. The mandrel also provides a specified blockage through the flow velocity meter, thereby increasing flow velocity through the meter. This allows flow rate measurements in conditions under which flow velocity in the under-restricted cross-sectional area of the pipe would normally be very low. Further, the mandrel can provide a specified restriction in the pipe, i.e., a venturi. By measuring the differential pressure across the venturi and utilizing the measured fluid velocity from the flow velocity meter, the density of the fluid mixture can be calculated. This calculated density can be used in conjunction with other measurements to determine phase fractions or to double check or to calibrate the phase fraction meter. The mandrel can be deployed without removing the meter from the conduit, allowing for easy adaptation to changing flow parameters and fluid compositions.
1. A system for measuring at least one parameter of a fluid flowing in a conduit, the conduit having a first cross sectional compliance, the system comprising:
at least one first flow meter disposed on the outside of the conduit for measuring at least one parameter of the fluid mixture, wherein the flow meter has a length along the axis of the conduit;
a mandrel disposed within the conduit and at least partially within the length of the flow meter, the mandrel configured to provide a second cross sectional compliance different than the first cross sectional compliance; and
a line coupled to the mandrel for disposing the mandrel into position within the conduit.
2. The system of claim 1 , wherein the flow meter comprises a velocity meter.
3. The system of claim 1 , wherein the flow meter comprises a meter for determining the speed of sound of the fluid.
4. The system of claim 1 , wherein the flow meter is fiber optic based.
5. The system of claim 4 , wherein the flow meter comprises a series of wraps wrapped around the outside of the conduit.
6. The system of claim 5 , further comprising fiber Bragg gratings between the wraps.
7. The system of claim 1 , wherein the mandrel modulates the first cross sectional compliance of the conduit.
8. The system of claim 1 , wherein the mandrel is hollow.
9. The system of claim 1 , wherein the mandrel is evacuated.
10. The system of claim 1 , wherein the conduit further comprises a seat for holding the mandrel.
11. The system of claim 1 , wherein the mandrel comprises an annular venturi having first diameter and a second diameter smaller than the first diameter.
12. The system of claim 11 , further comprising a first pressure sensor for measuring the pressure of the fluid proximate to the first diameter and a second pressure sensor for measuring the pressure of the fluid proximate to the second diameter.
13. The system of claim 1 , further comprising a second flow meter, wherein the mandrel is not disposed within the second flow meter.
14. The system of claim 1 , wherein the conduit comprises a production pipe for a well.
15. A method for determining the phase fractions of a fluid mixture flowing within a conduit, wherein the conduit comprises at least one first flow meter disposed on the outside of the conduit along a first axial length of the conduit, the method comprising:
disposing a mandrel within the conduit at least partially within the first length of the first flow meter to change a cross sectional compliance, wherein disposing the mandrel comprises seating the mandrel within the conduit;
computing the density of the fluid mixture using data from at least the first flow meter; and
computing the phase fractions of the components in the fluid mixture using the computed density of the mixture.
16. The method of claim 15 , wherein disposing the mandrel comprises the use of a line.
17. The method of claim 15 , wherein the flow meter comprises a meter for measuring the speed of sound of the fluid, and wherein the density of the fluid is computed using the measured speed of sound.
18. The method of claim 15 , wherein the flow meter is fiber optic based.
19. The method of claim 18 , wherein the flow meter comprises a series of wraps wrapped around the outside of the conduit.
20. The method of claim 19 , further comprising fiber Bragg gratings between the wraps.
21. The method of claim 15 , wherein the mandrel is hollow.
22. The method of claim 15 , wherein the mandrel is evacuated.
23. The method of claim 15 , wherein computing the density comprises
measuring a first speed of sound of the fluid mixture where the mandrel is disposed within the first length; and
measuring a second speed of sound of the fluid mixture where the mandrel is not disposed within the first length.
24. The method of claim 15 , wherein at least one second flow meter is disposed on the outside of the conduit at a location separate from the first axial length, and wherein the mandrel is not disposed within the conduit proximate to the second flow meter, and wherein computing the density comprises
measuring a first speed of sound of the fluid mixture using the first flow meter; and
measuring a second speed of sound of the fluid mixture using the second flow meter.
25. The method of claim 15 , wherein the mandrel comprises an annular venturi having first diameter and a second diameter smaller than the first diameter.
26. The method of claim 25 , further comprising measuring the pressure of the fluid mixture proximate to the first diameter and the second diameter.
27. The method of claim 15 , wherein the conduit comprises a production pipe for a well.
28. A method for determining the phase fractions of a fluid mixture flowing within a conduit, comprising in no particular order:
disposing a mandrel within me conduit at a first location to change a cross sectional compliance, wherein disposing the mandrel comprises seating the mandrel within the conduit;
measuring a first speed of sound of the fluid at the first location;
measuring a second speed of sound of the fluid at a second location different from the first location; and
using the first speed of sound and the second speed of sound to calculate the phase fraction of the fluid mixture.
29. The method of claim 28 , wherein the cross sectional compliancies at the first and second locations are different.
30. The method of claim 28 , wherein disposing the mandrel comprises the use of a line.
31. The method of claim 28 , wherein the first speed of sound and second speed of sound are measured using at least one flow meter disposed on the outside of the conduit.
32. The method of claim 31 , wherein the flow meter is fiber optic based.
33. The method of claim 32 , wherein the flow meter comprises a series of wraps wrapped around the outside of the conduit.
34. The method of claim 33 , further comprising fiber Bragg gratings between the wraps.
35. The method of claim 28 , wherein the mandrel is hollow.
36. The method of claim 28 , wherein the mandrel is evacuated.
37. The method of claim 28 , wherein the mandrel comprises an annular venturi.
38. The method of claim 28 , wherein using the first and second speed of sounds comprises computing the density of the fluid mixture.
39. The method of claim 28 , wherein the first speed of sound is measured using a first flow meter and the second speed of sound is measured using a second flow meter.
40. The method of claim 28 , wherein the first and second speed of sound are measured using a single flow meter.
41. The method of claim 28 , wherein the conduit comprises a production pipe for a well.
42. A method for determining the density of a fluid mixture flowing within a conduit, comprising in no particular order:
disposing a mandrel within the conduit at a first location to change a cross sectional compliance, wherein disposing the mandrel comprises the use of a line;
measuring a first speed of sound of the fluid at the first location;
measuring a second speed of sound of the fluid at a second location different from the first location; and
using the first speed of sound and the second speed of sound to calculate the density of the fluid mixture.
43. The method of claim 42 , wherein the cross sectional compliancies at the first and second locations are different.
44. The method of claim 42 , wherein disposing the mandrel comprises seating the mandrel within the conduit.
45. The method of claim 42 , wherein the first speed of sound and second speed of sound are measured using at least one flow meter disposed on the outside of the conduit.
46. The method of claim 45 , wherein the flow meter is fiber optic based.
47. The method of claim 46 , wherein the flow meter comprises a series of wraps wrapped around the outside of the conduit.
48. The method of claim 47 , further comprising fiber Bragg gratings between the wraps.
49. The method of claim 42 , wherein the mandrel is hollow.
50. The method of claim 42 , wherein the mandrel is evacuated.
51. The method of claim 42 , wherein the mandrel comprises a venturi.
52. The method of claim 42 , wherein the first speed of sound is measured using a first flow meter and the second speed of sound is measured using a second flow meter.
53. The method of claim 42 , wherein the first and second speed of sound are measured using a single flow meter.
54. The method of claim 42 , wherein the conduit comprises a production pipe for a well.