Launching pipeline pigs

Patent metadata

Field	Value
Publication number	US-12276365-B2
Application number	US-202017766727-A
Country	US
Kind code	B2
Filing date	Oct 7, 2020
Priority date	Oct 7, 2019
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

A pipeline pig is launched by directing a flow of fluid to, and through, the pig while conveying a launching element to the pig, entrained in the flow. Interaction between the launching element and the pig then blocks the flow through the pig to launch the pig. The launching element can be a spherical plug that blocks a through-passage extending longitudinally through the pig, hence serving as a barrier to the flow through the pig, or can trigger a mechanism that blocks the flow through the pig. The flow entraining the launching element can be directed through at least one other pig to be launched subsequently, positioned upstream of the pig being launched. A succession of launching elements can be released into the flow, each configured to interact with a respective one of a series of pigs. Successively released launching elements can increase in diameter from element to element.

First claim

The invention claimed is:

1. A method of launching a pipeline pig comprising:
said pig having a longitudinal through passage that is arranged to permit a flow of fluid through the pig, the through passage comprising a relatively wide upstream funnel portion that is asymmetrical about a central longitudinal axis of the pig, and a relatively narrow downstream portion; and
a seat for a discrete launching element that, when positioned in the seat, blocks the flow of fluid through the through passage, the launching element being conveyable to the pig entrained in the flow of fluid to engage the pig, wherein the seat is disposed between the relatively wide upstream funnel portion and the relatively narrow downstream portion of the through passage,
wherein the method comprises:
directing a flow of fluid to, and through, the pig being launched;

conveying a launching element to the pig by entraining the launching element in the flow of fluid;
engaging the launching element with the pig being launched; and
by interaction between the launching element and the pig, blocking the flow of fluid through the pig to launch the pig.

2. The method of claim 1 , comprising locking the engaged launching element to the pig being launched.

3. The method of claim 1 , comprising holding the launching element against the pig by virtue of differential pressure applied to the launching element.

4. The method of claim 1 , wherein the launching element serves as a barrier to the flow of fluid through the pig when so engaged.

5. The method of claim 1 , wherein the launching element interacts with the pig being launched by triggering a blocking mechanism of that pig, which mechanism consequently blocks the flow of fluid through that pig.

6. The method of claim 1 , comprising directing the flow of fluid through at least one other pig to be launched subsequently, which pig is positioned upstream of the pig being launched, with respect to the flow of fluid.

7. The method of claim 6 , comprising allowing the launching element to pass through the or each other pig with the flow of fluid.

8. The method of claim 6 , comprising releasing a succession of launching elements into the flow of fluid, each launching element being configured to interact with, and thereby to block the flow of fluid through, a respective one of a series of pigs disposed end to end in longitudinal succession.

9. The method of claim 8 , wherein the successively released launching elements are of increasing diameter from element to element.

10. The method of claim 1 , wherein the or each launching element has substantially neutral or slightly negative buoyancy in the flowing fluid.

11. The method of claim 1 , wherein the or each launching element is substantially spherical.

12. A launcher for pipeline pigs comprises a tubular body having:
a fluid inlet and an open end, defining a flow direction extending along a flow path within the body from the fluid inlet to the open end;
a pig storage region in the flow path for holding a series of pigs; and
at least one launching mechanism, positioned upstream of the pig storage region with respect to the flow direction;
wherein the or each launching mechanism is configured to hold at least one launching element and is operable to release the or each launching element into the flow path to launch a pig of the series in use;
the launcher further comprising a pig held in the pig storage region and a launching element held in the at least one launching mechanism;
wherein the pig comprises a longitudinal through passage that is arranged to permit a flow of fluid through the pig in the flow direction along the flow path, wherein at least a portion of the through passage is narrower than the launching element, the through passage comprising a relatively wide upstream funnel portion that is asymmetrical about a central longitudinal axis of the pig, and a relatively narrow downstream portion; and
a seat for the launching element, wherein the seat is disposed between the relatively wide upstream funnel portion and the relatively narrow downstream portion of the through passage; and
wherein the launching element is configured to engage the pig and to block the flow of fluid along the through passage to launch the pig, in response to releasing the launching element from the at least one launching mechanism onto the flow path.

13. The launcher of claim 12 , wherein the seat is shaped to complement the launching element.

14. The launcher of claim 12 , wherein an upstream portion of the through passage is wider than the launching element and a downstream portion of the through passage is narrower than the launching element.

15. The launcher of claim 14 , wherein at least a portion of the through passage tapers downstream with respect to the flow direction.

16. The launcher of claim 12 , wherein the pig storage region contains a series of pigs disposed end to end in longitudinal succession in the flow direction, the through passages of at least two pigs of the series being in mutual fluid communication.

17. The launcher of claim 16 , wherein the communicating through passages of the at least two pigs are in mutual radial alignment with respect to a central longitudinal axis of the tubular body.

18. The launcher of claim 16 , wherein the through passages of the at least two pigs have respective minimum widths that reduce from pig to pig in the flow direction.

19. The launcher of claim 12 , wherein the or each launching element is substantially spherical.

20. A pipeline pig, comprising:
a longitudinal through passage that is arranged to permit a flow of fluid through the pig, the through passage comprising a relatively wide upstream funnel portion that is asymmetrical about a central longitudinal axis of the pig, and a relatively narrow downstream portion; and
a seat for a discrete launching element that, when positioned in the seat, blocks the flow of fluid through the through passage, the launching element being conveyable to the pig entrained in the flow of fluid to engage the pig, wherein the seat is disposed between the relatively wide upstream funnel portion and the relatively narrow downstream portion of the through passage.

21. The pig of claim 20 , wherein the funnel portion has different inclination relative to the central longitudinal axis of the pig on different sides of that axis.

22. The pig of claim 20 , wherein a downstream portion of the through passage is offset laterally from the central longitudinal axis of the pig.

23. A pipeline pig, comprising:
a longitudinal through passage that is arranged to permit a flow of fluid through the pig; and
a blocking mechanism that is configured to block the flow of fluid through the through-passage in response to interaction with a discrete launching element that is conveyable to the pig, entrained in the flow of fluid, to engage the pig,
wherein the blocking mechanism comprises a sleeve and shutter elements, the sleeve being arranged to move in the through-passage from an upstream position to a downstream position when engaged by the launching element, and wherein movement of the sleeve causes the shutter elements to come together to block the flow of fluid through the through-passage.

24. The pig of claim 23 , wherein the through passage comprises an upstream funnel portion that is asymmetrical about a central longitudinal axis of the pig.

25. The pig of claim 24 , wherein the funnel

Assignees

• Subsea 7 Norway As

Inventors

• Juhlin Rasmus Asp

Classifications

• F16L55/38 Primary

  driven by fluid pressure · CPC title

• F16L55/46 Primary

  Launching or retrieval of pigs or moles · CPC title