US6716268B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Slugging control
Assignee: Lattice Intellectual Property Ltd
•
Filing: 2001-01-12
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Granted: 2004-04-06
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Expires: 2021-01-12
Abstract
Abstract A method of controlling occurrence of slugging in a riser of a pipeline arrangement including a riser base and pipeline conveying a multiphase fluid system in which the gas phase may be natural gas. The upper end of riser is connected to a separator vessel. The gas phase of the multiphase fluid system is separated from the liquid phase so that the separated gas leaves through gas outlet pipe controlled by a first valve, and the liquid leaves through an outlet pipe controlled by a first valve. The first valve regulates the velocity of gas along the pipeline towards the riser. A pressure sensor observes the gas pressure in the riser base, and if the observed pressure exceeds a predetermined control pressure value a three term pressure indication control causes the first valve to be operated to pen to an extent that increases the gas outflow through the pipe, and thus increases the velocity of gas in the pipeline to avoid occurrence of severe slugging in the riser. The observation of the predetermined control pressure value is deemed to signify incipient slugging.
Inventors
- 👤 Peter David Molyneux
- 👤 John Paul Kinvig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:24
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/34; E21B43/01; E21B43/12; F; F17; F17D; F17D1/00; F17D1/005; E21B2200/00; E21B2200/09; Y; Y10; Y10T; Y10T137/00; Y10T137/0318; Y10T137/0324; Y10T137/0379; Y10T137/8158; Y10T137/8326
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
143 words
A method of controlling occurrence of slugging in a riser of a pipeline conveying a multiphase fluid system, comprising: providing separator vessel means connected to an upper part of the riser to receive from the riser the multiphase fluid system for separation of a gas phase of the fluid system from a liquid phase; providing the separator vessel means with a gas outlet comprising valve means to regulate a flow gas from the separator vessel means and thereby regulate velocity of gas flow along the pipeline towards the riser in at least a vicinity of a lower end of the riser; observing pressure in the pipeline at a position adjacent to the riser; and varying an extent to which the valve means is open to vary gas velocity in the pipeline to a value opposing or preventing occurrence of slugging in the riser.
Claim 2
Independent Claim
143 words
A method of controlling occurrence of slugging in a riser of a pipeline conveying a multiphase fluid system, comprising: providing separator vessel means connected to an upper part of the riser to receive from the riser the multiphase fluid system for separation of a gas phase of the fluid system from a liquid phase; providing the separator vessel means with a gas outlet comprising valve means to regulate a flow gas from the separator vessel means and thereby regulate velocity of gas flow along the pipeline towards the riser in at least a vicinity of a lower end of the riser; observing pressure in the pipeline at a position adjacent to the riser; and varying an extent to which the valve means is open to vary gas velocity in the pipeline to a value opposing or preventing occurrence of slugging in the riser.
Claim 3
Dependent Claim
32 words
A method as claimed in claim 1 , wherein increasing the extent to which the valve means is opened increases velocity of the gas flow in the pipeline adjacent to the riser.
Claim 4
Dependent Claim
31 words
A method as claimed in claim 1 , wherein the extent to which the valve means is opened is increased in value when the observed pressure rises above a predetermined value.
Claim 5
Dependent Claim
29 words
A method as claimed in claim 1 , wherein the extent to which the valve means is opened is decreased when the observed pressure falls below a pre-determined value.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 4 , wherein said predetermined value is derived empirically.
Claim 7
Dependent Claim
32 words
A method as claimed in claim 1 , wherein the extent to which the valve means is opened is a function of an error between the observed pressure and a predetermined value.
Claim 8
Dependent Claim
29 words
A method as claimed in claim 1 , wherein the extent to which the valve means is opened is a function of an output from a three term control.
Claim 9
Dependent Claim
28 words
A method as claimed in claim 1 , wherein the valve means is operated to maintain the observed pressure in the pipeline substantially within a predetermined pressure range.
Claim 10
Dependent Claim
28 words
A method as claimed in claim 1 , wherein the valve means is operated to maintain the observed pressure in the pipeline at a substantially constant predetermined value.
Claim 11
Dependent Claim
52 words
A method as claimed in claim 1 , further comprising: providing the separator vessel means with a liquid outlet comprising second valve means; observing a level of the liquid in the separator vessel means; and closing the second valve means when the level of the liquid falls below a first predetermined level.
Claim 12
Dependent Claim
38 words
A method as claimed in claim 10 , wherein the second valve means is opened when the level of the liquid in the separator vessel means rises above a second predetermined level higher than the first predetermined level.
Claim 13
Dependent Claim
165 words
A pipeline to convey a multiphase fluid system, comprising: a riser; separator vessel means connected to an upper part of the riser to receive from the riser the multiphase fluid system to separate a gas phase of the system from a liquid phase, the separator vessel means being provided with a gas outlet comprising valve means to regulate flow of gas from the separator vessel means; pressure observing means to observe pressure in the pipeline adjacent to the riser and to provide a signal corresponding to observed pressure; control means responsive to the signal to cause the valve means to operate to vary an extent to which the valve means is open; wherein when the pressure observing means observes a pressure greater than a predetermined value the control means causes operation of the valve means to vary an extent to which the valve means is open to vary gas velocity in the pipeline to a value opposing or preventing occurrence of slugging in the riser.
Claim 14
Dependent Claim
165 words
A pipeline to convey a multiphase fluid system, comprising: a riser; separator vessel means connected to an upper part of the riser to receive from the riser the multiphase fluid system to separate a gas phase of the system from a liquid phase, the separator vessel means being provided with a gas outlet comprising valve means to regulate flow of gas from the separator vessel means; pressure observing means to observe pressure in the pipeline adjacent to the riser and to provide a signal corresponding to observed pressure; control means responsive to the signal to cause the valve means to operate to vary an extent to which the valve means is open; wherein when the pressure observing means observes a pressure greater than a predetermined value the control means causes operation of the valve means to vary an extent to which the valve means is open to vary gas velocity in the pipeline to a value opposing or preventing occurrence of slugging in the riser.
Claim 15
Dependent Claim
37 words
A pipeline as claimed in claim 12 , wherein the control means is arranged to cause the extent to which the valve means is opened to be increased when the observed pressure rises above the predetermined value.
Claim 16
Dependent Claim
45 words
A pipeline as claimed in claim 12 , wherein the control means is arranged such that the extent to which the valve means is opened in response to the control means is a function of an error between the observed pressure and the predetermined value.
References Cited (Backward Citations)
WO1987001759A1
Cited
EP0331295A1
Cited
EP0410522B1
Cited
US5478504A
Cited
US5390547A
Cited
WO1996000604A1
Cited
US6390114B1
Cited
WO2003033870A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-04-06 | 2007-10-06 | 2008-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-04-06 | 2011-10-06 | 2012-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-04-06 | 2015-10-06 | 2016-04-06 | $7700.00 | Window Closed / Lapsed |