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EP 1 759 086 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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29.07.2009 Bulletin 2009/31 |
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Date of filing: 23.06.2005 |
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International Patent Classification (IPC):
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International application number: |
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PCT/EP2005/052947 |
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International publication number: |
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WO 2006/003112 (12.01.2006 Gazette 2006/02) |
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SCREEN FOR CONTROLLING SAND PRODUCTION IN A WELLBORE
SIEB ZUR STEUERUNG DER SANDPRODUKTION IN EINEM BOHRLOCH
CREPINE PERMETTANT DE COMMANDER LA PRODUCTION DE SABLE DANS UN PUITS DE FORAGE
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Designated Contracting States: |
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DE FR GB NL |
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Priority: |
25.06.2004 EP 04253821
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Date of publication of application: |
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07.03.2007 Bulletin 2007/10 |
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Proprietor: Shell Internationale Research Maatschappij B.V. |
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2596 HR Den Haag (NL) |
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Inventors: |
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- BAAIJENS, Matheus Norbertus
NL-2288 GS Rijswijk (NL)
- CORNELISSEN, Erik Kerst
NL-2288 GS Rijswijk (NL)
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Representative: Zeestraten, Albertus W. J. et al |
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Shell International B.V.
Intellectual Property Services
P.O. Box 384 2501 CJ The Hague 2501 CJ The Hague (NL) |
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References cited: :
WO-A-00/45031 US-A1- 2002 020 527 US-A1- 2004 035 590
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WO-A-20/04022911 US-A1- 2002 148 612 US-A1- 2004 112 609
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a wellbore screen for controlling inflow of solid
particles into a wellbore, the wellbore screen comprising a conduit for transporting
fluid and an outer layer comprising a filter for filtering solid particles from fluid
flowing into the conduit.
[0002] Stand-alone sand exclusion systems, such as slotted liners or a wire-wrapped screens,
are generally applied in wells for producing a stream of fluid from the earth formation
and wells for injecting a stream of fluid into the earth formation. The produced and/or
injected stream of fluid can be, for example, oil, gas or water. A frequently occurring
problem in using such sand exclusion system relates to axial flow of fluid in the
annular space between the wellbore wall and the screen. Solids from the surrounding
formation which flow with the stream of fluid into the wellbore are thereby transported
along the screen and deposited as a layer of very low permeability on the screen.
The problem is particularly pronounced in case clay particles enter the wellbore.
As a result of such flow of fluid through the annular space plugging of the screen
potentially takes place over the full length thereof, which may lead to reduced production
of hydrocarbon fluid or water from the well. Moreover, if flow of fluid into the screen
is reduced to a local section of the screen not (yet) plugged, excessive erosion of
the screen may result.
[0003] WO 2004/022911 discloses a wellbore screen according to the preamble of claim 1.
[0004] US-A-2002/20527 discloses an outer perforated liner, an inner screen, and a matrix comprising a polymer
arranged between the outer perforated liner and the inner screen.
[0005] It is an object of the invention to provide an improved wellbore screen which overcomes
the aforementioned problems.
[0006] In accordance with the invention there is provided a wellbore screen for controlling
inflow of solid particles into a wellbore, the wellbore screen comprising a conduit
for transporting fluid, an outer layer comprising a filter for reducing inflow of
solid particles into the conduit, the outer layer extending around the conduit and
being radially expandable against the wellbore wall, and swelling means arranged between
the conduit and the outer layer, the swelling means being susceptible of swelling
upon contact with a selected fluid so as to radially expand the outer layer against
the wellbore wall.
[0007] In this manner it is achieved that, after contact of the swelling means with the
selected fluid, the outer layer with the filter included is biased against the wellbore
wall. Solid particles which locally enter the wellbore are thereby prevented from
flowing in longitudinal direction along the entire screen so that the risk of plugging
of the entire filter as a result of local inflow of solids is eliminated. Furthermore,
the expanded outer layer supports the wellbore wall so that sand failure at the wellbore
wall is largely reduced. Moreover the expanded outer layer provides a large inflow
area for the screen.
[0008] The wellbore can be, for example, a production well for the production of hydrocarbon
fluid (crude oil or gas) or water. Alternatively the wellbore can be an injection
well for injecting water, oil, gas, waste fluid or another fluid into the earth formation.
In either case the selected fluid which causes swelling of the swelling means can
be a produced fluid, such as hydrocarbon fluid or water, or an injected fluid such
as hydrocarbon fluid (e.g. crude oil, diesel or gas) or water.
[0009] In case of a production well for hydrocarbon fluid, fast activation can be achieved
by pumping a hydrocarbon fluid, such as diesel, into the wellbore to induce fast swelling
of the swelling means. Once fast swelling is achieved, swelling is maintained by virtue
of contact of the swelling means with produced hydrocarbon fluid.
[0010] It will be understood that in case of an injection well, the problem of plugging
can occur during time intervals that injection of fluid is stopped and fluid is allowed
to flow back from the wellbore into the screen.
[0011] Suitably the swelling means includes a plurality of swelleable rings, each ring extending
around the conduit and being susceptible of swelling upon contact with the selected
fluid, the rings being mutually spaced along the conduit, for example at regular mutual
spacings.
[0012] In another arrangement the swelling means includes a sleeve extending around the
conduit, the sleeve being provided with a plurality of through-openings spaced along
the sleeve, for example through-opening having a substantially rectangular shape or
a substantially circular shape.
[0013] In a preferred embodiment the swelling means includes a material susceptible of swelling
upon contact with hydrocarbon fluid or water.
[0014] In case of swelling upon contact with water the material for example is a rubber
selected from NBR, HNBR, XNBR, FKM, FFKM, TFE/P or EPDM base rubber.
[0015] In case of swelling upon contact with hydrocarbon fluid the material preferably includes
a rubber selected from natural rubber, nitrile rubber, hydrogenated nitrile rubber,
acrylate butadiene rubber, poly acrylate rubber, butyl rubber, brominated butyl rubber,
chlorinated butyl rubber, chlorinated polyethylene, neoprene rubber, styrene butadiene
copolymer rubber, sulphonated polyethylene, ethylene acrylate rubber, epichlorohydrin
ethylene oxide copolymer, ethylene-propylene-copolymer (peroxide crosslinked), ethylene-propylene-copolymer
(sulphur crosslinked), ethylene-propylene-diene terpolymer rubber, ethylene vinyl
acetate copolymer, fluoro rubber, fluoro silicone rubber, and silicone rubber.
[0016] Preferably said material is selected from EP(D)M rubber (ethylene-propylene-copolymer,
either peroxide or sulphur crosslinked), EPT rubber (ethylene-propylene-diene terpolymer
rubber), butyl rubber, brominated butyl rubber, chlorinated butyl rubber, and chlorinated
polyethylene.
[0017] Suitably the outer layer includes an annular filter layer and an annular shroud extending
around the annular filter layer.
[0018] The invention will be described hereinafter in more detail by way of example, with
reference to the accompanying drawings in which:
Fig. 1 schematically shows a longitudinal view in section of an embodiment of a wellbore
screen according to the invention, before swelling of the swelling means;
Fig. 2 schematically shows a longitudinal view in section of the embodiment of Fig.
1, after swelling of the swelling means;
Fig. 3 schematically shows cross-section 3-3 of Fig. 1; and
Fig. 4 schematically shows cross-section 4-4 of Fig. 2.
[0019] In the Figures like reference signs relate to like components.
[0020] Referring to Figs. 1 and 2 there is shown a wellbore screen 1 arranged in a wellbore
2 for the production of hydrocarbon fluid. The screen 1 comprises a tubular member
3, a permeable annular outer layer 4 extending at a radial distance around the tubular
member 3, the outer layer 4 being formed of a filter layer 4a and a shroud 4b at the
outside of the filter layer 4a, and a plurality of swelleable elements in the form
of rings 6 arranged between the tubular member 3 and the outer layer 4. The rings
6 are arranged at regular spacings along the tubular member 3. The outer layer 4 is
flexible and radially expandable to at least an expansion ratio whereby the shroud
4b contacts the wellbore wall. Furthermore the filter layer 4a has a sieve opening
size adapted to prevent flow of solid particles into the tubular member 3. The rings
6 are made of an elastomer which swells upon contact with hydrocarbon fluid, the elastomer
being for example EPDM rubber. The tubular member 3 has a plurality of perforations
7 for inflow of produced hydrocarbon fluid into the tubular member 3, and is at it
ends provided with respective connector portions 8, 10 for interconnecting the wellbore
screen 1 to a conduit 9 for transporting produced hydrocarbon fluid to surface.
[0021] In Fig. 1 is shown the wellbore screen 1 before swelling of the rings 6 upon contact
with produced hydrocarbon fluid, so that the outer layer 4 is in its unexpanded state
whereby a clearance 11 exists between the shroud 4b and the wellbore wall.
[0022] In Fig. 2 is shown the wellbore screen 1 after swelling of the rings 6 upon contact
with hydrocarbon fluid, whereby the outer layer 4 has been radially expanded by the
swelling rings 6 so that the annular shroud 4b contacts the wall of the wellbore 2.
[0023] In Fig. 3 is shown the wellbore screen 1 and wellbore 2 in cross-section before swelling
of the rings 6. As shown the filter layer 4a is formed of a plurality of mutually
overlapping filter sheets 5. Each filter sheet 5 is at one end thereof connected to
one or more of the rings 6 by a respective lug 14, and overlaps with an adjacent filter
sheet 5. The shroud 4b is a thin metal sleeve provided with a mesh of longitudinal
slots (not shown) overlapping in longitudinal direction which renders the shroud 4b
extremely flexible to radial expansion while providing adequate protection to the
filter layer 4a.
[0024] Referring to Fig. 4 there is shown the wellbore screen 1 and wellbore 2 in cross-section
after swelling of the rings 6. The outer layer 4 has been expanded against the wellbore
wall, whereby during expansion of the filter layer 4a sliding of adjacent filter sheets
5 relative each other has occurred, and whereby during expansion of the shroud 4b
widening of the slots of the shroud 4b has occurred.
[0025] For reason of simplicity, in the figures not all rings 6 and perforations 7 are indicated
with a reference sign.
[0026] During normal use the wellbore screen 1 is lowered into the wellbore 2 and positioned
in the hydrocarbon fluid bearing zone of the surrounding formation, whereby the rings
6 are in their respective un-swollen state and the clearance 11 is present between
the outer layer 4 and the wall of the wellbore 2 (Fig. 1). When the well 2 is taken
in production, a stream of crude oil flows from the surrounding formation into the
wellbore 2 and from there via the outer layer 4 and the perforations 7 into the tubular
member 3. Thus the stream of hydrocarbon fluid flows along the rings 6 which thereby
swell from their unexpanded state (Fig. 1) to their expanded state (Fig. 2). Upon
swelling, the rings 6 push in radially outward direction against the outer layer 4
which as a result thereof is expanded against the wall of the wellbore 2. Since the
swelling force exerted by the set of rings is distributed along the length of the
outer layer 4, the outer layer 4, after expansion thereof, will be substantially compliant
with the larger irregularities of the wellbore wall. The sieve opening size of the
filter layer 4a does not change by the radial expansion since during expansion of
the filter layer 4a the individual filter sheets 5 slide relative to each other so
that the amount of overlap of adjacent filter sheets 5 decreases. The degree of overlap
of adjacent filter sheets 5 is selected so that after expansion of the filter layer
4a sufficient overlap of the filter sheets 5 remains to ensure that no open spots
occur which could allow fluid to bypass the filter layer 4a.
[0027] If desired, accelerated swelling of the rings 6 can be achieved by pumping diesel,
or any other suitable fluid, into the wellbore 2 before the well is taken in production.
[0028] It is thus achieved that the stream of hydrocarbon fluid is prevented from flowing
in axial direction along the outside of the outer layer 4 so that sand or clay particles
which may have locally entered into the stream of hydrocarbon fluid, are prevented
from flowing in longitudinal direction along the entire outer layer 4. Thus is an
important advantage because such flow of particles along the entire outer layer 4
could otherwise lead to plugging of the entire filter layer 4b, particularly in case
of clay particles entering the wellbore.
[0029] Additional advantages of the wellbore screen relate to the solid pre-drilled tubular
member which has a high collapse resistance, the annular space between the tubular
member and the outer layer which provides good inflow characteristics for produced
fluid, and the expansion mechanism which obviates the need to mechanically expand
the tubular member.
[0030] Instead of all rings being made of an elastomer which swells upon contact with hydrocarbon
fluid, one or more of the rings can be made of a material which swells upon contact
with water produced from the earth formation. For example the rings can include a
first set of rings susceptible of swelling in hydrocarbon fluid and a second set of
rings susceptible of swelling in water, whereby the rings of the first and second
sets are arranged in alternating order.
[0031] Furthermore, instead of connecting each filter sheet at one end thereof to some or
all of the rings, any other suitable portion of the filter sheet can be connected
to the rings. Also the filter sheets can be held in place by the shroud so that there
is no need for connecting the filter sheets to some or al of the rings.
[0032] As an alternative to the slotted shroud with overlapping longitudinal slots, any
other suitable shroud can be used, for example a foldable shroud provided with hinges
to allow unfolding of the shroud, or a shroud formed of a plurality of interconnected
small tubulars whereby the individual tubulars become flattened upon expansion of
the shroud.
1. A wellbore screen for controlling inflow of solid particles into a wellbore, the wellbore
screen (1) comprising a conduit (3) for transporting fluid, an outer layer (4) comprising
a filter (4a) for reducing inflow of solid particles into the conduit (3), the outer
layer (4) extending around the conduit (3) and being radially expandable, and swelling
means (6) susceptible of swelling upon contact with a selected fluid, characterised in that the outer layer (4) is radially expandable against the wellbore wall (2), that the
swelling means (6) is arranged between the conduit (3) and the outer layer, and that
swelling of the swelling means (6) is so as to radially expand the outer layer (4)
against the wellbore wall.
2. The wellbore screen of claim 1, wherein the swelling means (6) includes a plurality
of swelleable rings (6), each ring extending around the conduit (3) and being susceptible
of swelling upon contact with the selected fluid, the rings (6) being mutually spaced
along the conduit.
3. The wellbore screen of claim 2, wherein the rings (6) are arranged at regular mutual
spacings along the conduit (3).
4. The wellbore screen of claim 1, wherein the swelling means (6) includes a sleeve extending
around the conduit (3), the sleeve being provided with a plurality of through-openings
spaced along the sleeve.
5. The wellbore screen of claim 4, wherein each through-opening has a substantially rectangular
shape or a substantially circular shape.
6. The wellbore screen of any one of claims 1-5, wherein the swelling means (6) includes
a material susceptible of swelling upon contact with hydrocarbon fluid or water.
7. The wellbore screen of claim 6, wherein said material is susceptible of swelling upon
contact with water and includes a rubber selected from Nitrile Butadiene rubber, Hydrogenated
Nitrile Butadiene rubber, Carboxylated Nitrile Butadiene rubber, Fluor Polymer, TetraFluorEthylene/PolyPropylene,
Ethylene-Propylene-Diene Terpolymer rubber, Chloroprene rubber, ChloroSulfonated Polyethylene,
Chlorinated Polyethylene, and PolyUrethane rubber.
8. The wellbore screen of claim 6, wherein said material is susceptible of swelling upon
contact with hydrocarbon fluid and includes a rubber selected from Natural rubber,
Acrylate Butadiene rubber, Butyl rubber, Brominated Butyl rubber, Chlorinated Butyl
rubber, Chlorinated Polyethylene, Chloroprene rubber, Styrene Butadiene rubber, Sulphonated
Polyethylene, Ethylene Acrylate rubber, Epichlorohydrin Ethylene Oxide Copolymer,
Epichlorohydrin Ethylene Oxide Terpolymer, Ethylene-Propylene-Copolymer (Peroxide
crosslinked), Ethylene-Propylene-Diene Terpolymer rubber, and Silicone rubber.
9. The wellbore screen of claim 8, wherein said material is selected from Ethylene Propylene
Copolymer (Peroxide crosslinked), Ethylene-Propylene-Diene Terpolymer rubber, Butyl
rubber, Brominated Butyl rubber, Chlorinated Butyl rubber, and Chlorinated Polyethylene.
10. The wellbore screen of any one of claims 1-9, wherein the outer layer (4) includes
an annular filter layer (4a) and an annular shroud (4b) extending around the annular
filter layer (4a).
11. The wellbore screen of any one of claims 1-10, wherein the wellbore is a wellbore
for the production of hydrocarbon fluid or water from the earth formation.
1. Bohrlochfilter zum Steuern des Einströmens von Feststoffteilchen in ein Bohrloch,
wobei der Bohrlochfilter (1) eine Leitung (3) für den Fluidtransport aufweist, eine
äußere Lage (4), die einen Filter (4a) zum Reduzieren des Einströmens von Feststoffteilchen
in die Leitung (3) aufweist, wobei sich die äußere Lage (4) um die Leitung (3) erstreckt
und radial expandierbar ist, und Schwellmittel (6), die befähigt sind, bei Kontakt
mit einem vorbestimmten Fluid anzuschwellen, dadurch gekennzeichnet, daß die äußere Lage (4) radial gegen die Bohrlochwand (2) expandierbar ist, daß die Schwellmittel
(6) zwischen der Leitung (3) und der äußeren Lage (4) angeordnet sind, und daß das
Schwellen der Schwellmittel (6) derart erfolgt, daß sie die äußere Lage (4) radial
gegen die Bohrlochwand expandieren.
2. Bohrlochfilter nach Anspruch 1, bei welchem die Schwellmittel (6) eine Vielzahl von
Schwellringen (6) aufweisen, wobei sich jeder Ring um die Leitung (3) erstreckt und
bei Kontakt mit einem vorbestimmten Fluid anschwillt, wobei die Ringe (6) entlang
der Leitung gegenseitigen Abstand haben.
3. Bohrlochfilter nach Anspruch 2, bei welchem die Ringe (6) in gleichmäßigen gegenseitigen
Abständen entlang der Leitung (3) angeordnet sind.
4. Bohrlochfilter nach Anspruch 1, bei welchem die Schwellmittel (6) eine Umhüllung aufweisen,
die sich um die Leitung (3) erstreckt, wobei die Umhüllung mit einer Vielzahl von
Durchtrittsöffnungen versehen ist, die entlang der Umhüllung beabstandet sind.
5. Bohrlochfilter nach Anspruch 4, bei welchem jede Durchtrittsöffnung im wesentlichen
rechteckige Gestalt oder im wesentlichen kreisförmige Gestalt hat.
6. Bohrlochfilter nach einem der Ansprüche 1-5, bei welchem die Schwellmittel (6) ein
Material aufweisen, das befähigt ist, bei Kontakt mit Kohlenwasserstofffluid oder
Wasser anzuschwellen.
7. Bohrlochfilter nach Anspruch 6, bei welchem das Material bei Kontakt mit Wasser anschwillt
und einen Gummi enthält, der aus Nitrilbutadiengummi, hydriertem Nitrilbutadien-gummi,
carboxyliertem Nitrilbutadiengummi, Fluorpolymer, Tetrafluorethylen/Polypropylen,
Ethylen-Propylen-Dienterpolymergummi, Chloroprengummi, chlorsulfoniertem Polyethylen,
chloriertem Polyethylen und Polyurethangummi gewählt ist.
8. Bohrlochfilter nach Anspruch 6, bei welchem das Material bei Kontakt mit Kohlenwasserstofffluid
anschwillt und einen Gummi enthält, der aus Naturkautschuk, Acrylatbutadiengummi,
Butylgummi, bromiertem Butylgummi, chlorier- tem Butylgummi, chloriertem Polyethylen,
Chloroprengummi, Styrolbutadiengummi, sulfoniertem Polyethylen, Ethylen-acrylatgummi,
Epichlorhydrin-Ethylenoxid-Copolymer, Epi-chlorhydrin-Ethylenoxid-Terpolymer, Ethylen-Propylen-Copolymer
(peroxidvernetzt), Ethylen-Propylen-Dienterpolymergummi und Silikongummi gewählt ist.
9. Bohrlochfilter nach Anspruch 8, bei welchem das Material aus Ethylen-Propylen-Copolymer
(peroxidvernetzt), Ethylen-Propylen-Dienterpolymergummi, Butylgummi, bromiertem Butylgummi,
chloriertem Butylgummi und chloriertem Polyethylen gewählt ist.
10. Bohrlochfilter nach einem der Ansprüche 1-9, bei welchem die äußere Lage (4) eine
ringförmige Filterlage (4a) und eine ringförmige Abschirmung (4b) umfaßt, die sich
um die ringförmige Filterlage (4a) erstreckt.
11. Bohrlochfilter nach einem der Ansprüche 1-10, bei welchem das Bohrloch ein Bohrloch
zur Förderung von Kohlenwasserstofffluid oder Wasser aus der Erdformation ist.
1. Crépine de puits de forage destinée à maîtriser un afflux de particules solides dans
un puits de forage, la crépine de puits de forage (1) comprenant une
conduite (3) destinée à transporter un fluide, une couche extérieure (4) comprenant
un filtre (4a) destiné à réduire l'afflux de particules solides dans la
conduite (3), la couche extérieure (4) s'étendant autour de la conduite (3) et étant
radialement extensible, et un moyen de gonflement (6) susceptible de gonfler au contact
d'un fluide sélectionné, caractérisée en ce que la couche extérieure (4) peut s'étendre radialement contre la paroi du puits de forage
(2), en ce que le moyen de
gonflement (6) est disposé entre la conduite (3) et la couche extérieure, et en ce que le gonflement du moyen de gonflement (6) est tel qu'il étend radialement la couche
extérieure (4) contre la paroi du puits de forage.
2. Crépine de puits de forage selon la revendication 1, dans laquelle le moyen de gonflement
(6) comprend une pluralité d'anneaux gonflables (6), chaque anneau s'étendant autour
de la conduite (3) et étant susceptible de gonfler au contact du fluide sélectionné,
les anneaux (6) étant espacés les uns des autres le long de la conduite.
3. Crépine de puits de forage selon la revendication 2, dans laquelle les anneaux (6)
sont disposés selon des espacements réguliers les uns par rapport aux autres, le long
de la conduite (3).
4. Crépine de puits de forage selon la revendication 1, dans laquelle le moyen de gonflement
(6) comprend un manchon s'étendant autour de la conduite (3), le manchon étant muni
d'une pluralité d'ouvertures traversantes espacées le long du manchon.
5. Crépine de puits de forage selon la revendication 4, dans laquelle chaque ouverture
traversante a une forme sensiblement rectangulaire ou une forme sensiblement circulaire.
6. Crépine de puits de forage selon l'une quelconque des revendications 1 à 5, dans laquelle
le moyen de gonflement (6) comprend un matériau susceptible de gonfler au contact
d'un fluide hydrocarboné ou de l'eau.
7. Crépine de puits de forage selon la revendication 6, dans laquelle ledit matériau
est susceptible de gonfler au contact de l'eau et comprend un caoutchouc sélectionné
parmi un caoutchouc de nitrile-butadiène, un caoutchouc de nitrile-butadiène hydrogéné,
un caoutchouc de nitrile-butadiène carboxylé, un polymère fluoré, un tétrafluoroéthylène
/ polypropylène, un caoutchouc terpolymère d'éthylène-propylène-diène, un caoutchouc
de chloroprène, un polyéthylène chlorosulfoné, un polyéthylène chloré et un caoutchouc
de polyuréthane.
8. Crépine de puits de forage selon la revendication 6, dans laquelle ledit matériau
est susceptible de gonfler au contact d'un fluide hydrocarboné et comprend un caoutchouc
sélectionné parmi un caoutchouc naturel, un caoutchouc d'acrylate-butadiène, un caoutchouc
de butyle, un caoutchouc de butyle bromé, un caoutchouc de butyle chloré, un polyéthylène
chloré, un caoutchouc de chloroprène, un caoutchouc de styrène butadiène, un polyéthylène
sulfoné, un caoutchouc d'acrylate-éthylène, un copolymère d'épichlorhydrine et d'oxyde
d'éthylène, un terpolymère d'épichlorhydrine et d'oxyde d'éthylène, un copolymère
d'éthylène et de propylène (péroxyde réticulé), un caoutchouc terpolymère d'éthylène-propylène-diène,
et un caoutchouc de silicone.
9. Crépine de puits de forage selon la revendication 8, dans laquelle ledit matériau
est sélectionné parmi un copolymère d'éthylène et de propylène (péroxyde réticulé),
un caoutchouc terpolymère d'éthylène-propylène-diène, un caoutchouc de butyle, un
caoutchouc de butyle bromé, un caoutchouc de butyle chloré et un polyéthylène chloré.
10. Crépine de puits de forage selon l'une quelconque des revendications 1 à 9, dans laquelle
la couche extérieure (4) comprend une couche formant filtre annulaire (4a) et une
enveloppe annulaire (4b) s'étendant autour de la couche formant filtre annulaire (4a).
11. Crépine de puits de forage selon l'une quelconque des revendications 1 à 10, dans
laquelle le puits de forage est un puits de forage destiné à la production d'un fluide
hydrocarboné ou d'eau à partir de la formation terrestre.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description