EP0331295B1 - Assemblage de pipelines pour séparer au moins un courant diphasique - Google Patents

Assemblage de pipelines pour séparer au moins un courant diphasique Download PDF

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Publication number
EP0331295B1
EP0331295B1 EP89301091A EP89301091A EP0331295B1 EP 0331295 B1 EP0331295 B1 EP 0331295B1 EP 89301091 A EP89301091 A EP 89301091A EP 89301091 A EP89301091 A EP 89301091A EP 0331295 B1 EP0331295 B1 EP 0331295B1
Authority
EP
European Patent Office
Prior art keywords
pipeline
riser
gas
junction
main
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP89301091A
Other languages
German (de)
English (en)
Other versions
EP0331295A1 (fr
Inventor
Oyvind Kaasa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Norsk Hydro ASA
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Norsk Hydro ASA
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Filing date
Publication date
Application filed by Norsk Hydro ASA filed Critical Norsk Hydro ASA
Publication of EP0331295A1 publication Critical patent/EP0331295A1/fr
Application granted granted Critical
Publication of EP0331295B1 publication Critical patent/EP0331295B1/fr
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17D—PIPE-LINE SYSTEMS; PIPE-LINES
    • F17D1/00—Pipe-line systems
    • F17D1/005—Pipe-line systems for a two-phase gas-liquid flow
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/34—Arrangements for separating materials produced by the well
    • E21B43/36—Underwater separating arrangements
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B2200/00—Special features related to earth drilling for obtaining oil, gas or water
    • E21B2200/09—Detecting, eliminating, preventing liquid slugs in production pipes

Definitions

  • the present invention relates to a system for the separation underwater of the phases of a two-phase fluid flow into respective risers, e.g. as with an offshore platform, where oil and gas are transported by a pipeline along the seabed and by risers to the platform.
  • a two-phase flow in a horizontal pipeline system gives various flow patterns depending on the pipe diameter, geometry temperature and type of oil. Generally said, the flow pattern can be divided into the following categories: stratified, bubble, slug and annular flow.
  • a two-phase flow in a vertical pipe can also be divided into various flow patterns.
  • the slug flow will give the greatest problems as mentioned above.
  • the extreme slugging depends on the geometry and occurs only in the riser when the oil and gas velocity is so low that the horizontal flow is stratified.
  • Normal slugging is hydrodynamic and can be formed both in the horizontal and the vertical pipe section.
  • a separator for separation of the liquid- and gaseous phase has previously been developed.
  • the gas and oil are separated by feeding the flow from one common pipe into two or more parallel pipes.
  • Such separators require large space and are expensive to build.
  • a common feature of the aforementioned three types of slug catchers is that all three make use of some type of phase separator on the platform. Since the total capacity of the slug catchers has to be-.larger than the largest expected slugs it will occupy expensive and limited space on the platform.
  • a system for underwater phase separation of a fluid flow having at least two phases, such as oil and gas, from a seabed oil well including an underwater pipeline, a main riser connected to the pipeline and a secondary riser provided with flow restriction means and connected to the pipeline via a T-junction located upstream of the main riser is characterised in that the main riser is connected to a storage tank, the secondary riser is for gas transport and is connected to a gas scrubber, the flow restriction means is a controlled regulating valve, and in that there is a control means in the pipeline between the risers and responsive to the position of the liquid/gas interface along the pipeline so as to control the setting of the regulating valve to maintain the position of the said interface constant.
  • This allows for a total separation of the phases of a two-phase flow on the seabed and outside the platform, e.g. in a pipe system connecting the oil/gas pipeline on the seabed with the processing plant onshore.
  • the system is especially designed to deal with extreme slugs which occur normally at low liquid and gas velocity, i.e. at startup and shut-down of the production.
  • the main advantage of the system, which is designed to be located on the seabed, is that it has no moving parts, is simple and easy to manufacture, and is reliable and simple to maintain.
  • Figure 1 illustrates an offshore platform 10 for transportation and processing of oil and gas from a remote subsea installation or well via riser 2 to the processing plant on the platform 10.
  • the pipeline 1 is connected to a separate secondary riser 3 via T-junction 5 located at a distance X from the riser 2.
  • the secondary riser is connected to a gas scrubber 6 located on the platform.
  • a storage tank 4 is provided with a drainpipe 12 for the oil and one discharge pipe 13 for any gas that has evaporated from or was mixed with the oil.
  • a detection means 8 is provided to determine the location along the pipe 1 of any oil/gas interface. As shown, this detector comprises five capacitive detectors K1-K5 arranged in the pipeline section between the T-junction 5 and the riser 2. The capacitive detectors K1-K5 detect the presence of an oil/gas interface in the pipeline. The capacitive detectors are connected to a level indicator and give electrical signals to a control unit (not shown) which controls a regulating valve 7 located on the secondary riser 3.
  • the oil and gas transported in the main pipeline 1 are separated at the T-junction 5, where the gas components of the two-phase flow pass into the secondary riser 3 and the oil components pass into the pipeline 1 downstream of the T-junction and into the riser 2.
  • the pipeline 1 between the T-junction and the riser 2 should be slightly sloped so that a liquid seal is formed in the riser.
  • the regulating valve 7, by venting the gas, regulates the pressure in the pipeline 1 and in the riser 2. The regulation is done according to the signals from the capacitive detectors K1-K5 in the pipeline.
  • the regulating valve 7 will open at increasing gas pressure in the secondary riser when the liquid/gas interface reaches the detector K1.
  • the riser 2 will therefore contain fluid which is 100% oil and the oil/gas interface at all times will be located between the T-junction and the riser 2.
  • the accuracy of the oil/gas interface detection is of course dependent on the number of detectors situated in the pipeline and the distance between them.
  • the detection means may comprise more or less than five capacitive detectors or equivalent detectors of another type capable of detecting the presence of the liquid/gas interface.
  • Such detectors might comprise pressure sensors located in the scrubber, the storing tank and the pipeline. By means of the difference and the variation of pressure the position of the liquid/gas interface in the pipeline can be determined.
  • the pipes may have different diameters and lengths. To determine the optimum length of the pipes it is important to make sure that the system can deal with the peak values of slugs. Tests have shown that a distance X between the T-junction 5 and the riser 2 should be at least two times the height of the riser.
  • the pipes can be of different diameters, it is regarded as being an advantage to be able to clean the inside of the pipes by using a "pig".
  • the pipeline 1 and the risers 2, 3 should therefore have the same diameter and be as free as possible of obstacles such as valves, bends, etc.
  • the angle of inclination of the pipeline between the tee section and the riser is also important. Tests have indicated that it should be approximately 2° to the horizontal. To achieve the best separation of the two-phase flow the angle between the upright of the T-junction 5 and the main pipeline 1 may be an angle other than 90°, as illustrated in the drawings.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Geology (AREA)
  • Fluid Mechanics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Pipeline Systems (AREA)
  • Earth Drilling (AREA)
  • Paper (AREA)
  • Maintenance And Management Of Digital Transmission (AREA)

Claims (7)

  1. Système de séparation sous-marine de phases d'un débit de fluide comportant un minimum de deux phases, telles que l'huile et le gaz, à partir d'un puits de pétrole au fond de la mer, le système comportant un oléo-gazoduc sous-marin, un montant principal raccordé à l'oléo-gazoduc sous-marin et un montant secondaire comportant des moyens d'étranglement du débit et raccordé à l'oléo-gazoduc, caractérisé en ce que, le montant principal (2) est raccordé à un réservoir (4), le montant secondaire (3) prévu pour transporter le gaz est raccordé à un épurateur de gaz (6), les moyens d'étranglement (7) consistent d'un robinet régulateur, et en ce que des moyens de commande (8) sont prévus dans l'oléo-gazoduc entre les montants et répondent à la position de l'interface liquide/gaz le long de l'oléo-gazoduc de manière à ajuster le réglage du robinet régulateur (7) de manière à maintenir constante la position de la dite interface.
  2. Système selon la revendication 1 dont les moyens régulateurs comportent des moyens capteurs K¹ à K⁵ situés au minimum le long de l'oléo-gazoduc entre le montant principal (2) et le raccord en Té (5) raccordant le montant secondaire (3) à l'oléo-gazoduc.
  3. Système selon la revendication 2 dont les moyens capteurs comportent une série de capteurs capacitifs K¹-K⁵ situés dans l'oléo-gazoduc, chacun répondant à la proximité de l'interface du gaz/liquide.
  4. Système selon la revendication 2 dont les moyens capteurs comportent des capteurs de pression, ces derniers étant également agencés dans l'épurateur de gaz (6) et le réservoir (4), tous deux étant situés dans le matériel de séparation.
  5. Système selon l'une des revendications précédentes selon lesquelles la distance entre le raccord en Té (5) reliant le montant secondaire (3) à l'oléo-gazoduc (1) et au montant principal (2) mesure au minimum deux fois la hauteur du montant principal.
  6. Système selon l'une des revendications précédentes dont le tronçon d'oléo-gazoduc situé entre les deux montants est incliné pour s'éloigner du raccord en Té.
  7. Système selon la revendication 6 dont l'angle d'inclinaison est de 2°.
EP89301091A 1988-02-03 1989-02-03 Assemblage de pipelines pour séparer au moins un courant diphasique Expired EP0331295B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO880465A NO163424C (no) 1988-02-03 1988-02-03 Integrert system for omforming av stroemningsmoenster.
NO880465 1988-02-03

Publications (2)

Publication Number Publication Date
EP0331295A1 EP0331295A1 (fr) 1989-09-06
EP0331295B1 true EP0331295B1 (fr) 1992-12-09

Family

ID=19890632

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89301091A Expired EP0331295B1 (fr) 1988-02-03 1989-02-03 Assemblage de pipelines pour séparer au moins un courant diphasique

Country Status (5)

Country Link
EP (1) EP0331295B1 (fr)
BR (1) BR8900411A (fr)
DE (1) DE68903771T2 (fr)
ES (1) ES2036339T3 (fr)
NO (1) NO163424C (fr)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8917026D0 (en) * 1989-07-25 1989-09-13 Shell Int Research Method and apparatus for preventing slug growth in a pipeline
BR9303910A (pt) * 1993-09-27 1995-05-30 Petroleo Brasileiro Sa Método para eliminação de intermitência severa em linhas submarinas de fluxo multifásico
BR9602747A (pt) * 1996-06-12 1998-09-08 Petroleo Brasileiro Sa Método e aparelhagem para produç o submarina de petróleo através da injeç o intermitente de gás
EP1409834A2 (fr) 2000-01-17 2004-04-21 Lattice Intellectual Property Limited Prevention de la formation de bouchons
GB0000945D0 (en) * 2000-01-17 2000-03-08 Bg Intellectual Pty Ltd Control of slugging in a riser
NO320414B1 (no) * 2002-02-04 2005-12-05 Statoil Asa Undervanns flerfaserorledning
NO316840B1 (no) * 2002-08-16 2004-05-24 Norsk Hydro As Rorseparator for separasjon av fluid, spesielt olje, gass og vann
FR2875260B1 (fr) * 2004-09-13 2006-10-27 Inst Francais Du Petrole Systeme pour neutraliser la formation de bouchon de liquide dans une colonne montante
DE602006016475D1 (de) * 2005-11-28 2010-10-07 Shell Int Research Verfahren zum empfang von fluid aus einem erdgasrohr
US8726982B2 (en) 2008-04-28 2014-05-20 Shell Oil Company Method of producing gaseous and liquid components from one or more multi-phase streams and apparatus therefor
AU2009242194B2 (en) * 2008-04-28 2012-02-09 Shell Internationale Research Maatschappij B.V. Method of bypassing a pipeline in a multiple pipeline system
IT1396435B1 (it) 2009-11-16 2012-11-23 Eni Spa Procedimento di separazione di una corrente multifise che scorre lungo una condotta mediante giunto a t.

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4160652A (en) * 1977-08-26 1979-07-10 Texas Eastern Engineering, Ltd. Method and apparatus for handling the fluids in a two-phase flow pipeline system
NO157467C (no) * 1985-09-18 1988-03-23 Sintef Anordning for oppsamling av vaeskeplugger i en gassfoerende roerledning.
US4708793A (en) * 1986-06-13 1987-11-24 Atlantic Richfield Company System for separating gas-liquid flowstreams

Also Published As

Publication number Publication date
BR8900411A (pt) 1989-09-26
EP0331295A1 (fr) 1989-09-06
NO880465L (no) 1989-08-04
NO880465D0 (no) 1988-02-03
ES2036339T3 (es) 1993-05-16
DE68903771D1 (de) 1993-01-21
DE68903771T2 (de) 1993-05-13
NO163424B (no) 1990-02-12
NO163424C (no) 1991-11-28

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