OA11878A - Downhole device for controlling fluid flow in a well. - Google Patents

Abstract

A downhole device for controlling the flow of fluids through an oil and/or gas production well comprises a deformable chamber which contains an electromagnetic field or other stimuli responsive gel and a fluid passage which is closed off in response to a volume increase of the gel and the deformable chamber.

Description

1 118 78

DOWNHOLE DEVICE FOR CONTROLLING FLUID FLOW IN A WELL

Background of the Invention

The invention relates to a downhole device for controlling fluid flow through a hydrocarbon fluidproduction well. 5 Numerous devices exist for controlling fluid flow in wells. These devices generally comprise a valve bodywhich opens or closes a fluid passage in response toactuation of the valve body by an electric or hydraulicmotor. 10 Since the fluid pressure and pressure differentials across the downhole valve are generally high, powerfulelectric or hydraulic motors are required which requiresa significant space in the generally narrow wellbore anddeployment of high power and high voltage or high 15 pressure electric or hydraulic power supply conduits.

It is an object of the présent invention to provide a downhole fluid control device for use in a hydrocarbonproduction well which is compact and can be operatedwithout requiring high voltage or high pressure power 20 supply conduits.

Summary of the Invention

The downhole device according to the inventioncomprises a déformable chamber which contains a stimuliresponsive gel, which gel has a volume that varies in 25 response to variation of a selected physical stimulating parameter, and a fluid passage which is closed off inresponse to a volume increase of at least part of the geland the déformable chamber.

Preferably the gel is an electromagnetic field 30 responsive gel which releases water if an electromagnetic field of a certain field strength is exerted to the gel 2 118 7 8 and which absorbs water in the absence of an electro-magnetic field and the device is equipped with anelectromagnetic field transmitter which is adapted toexert an electromagnetic field of a selected fieldstrength to the gel.

Suitable electromagnetic field responsive gels arepolyacrylamide gels and polymethylacrylic acid gels.Electromagnetic field responsive gels of this type areknown from US patent No. 5,100,933, International patentapplication WO 9202005 and Japanese patent No. 2711119.These prior art references disclose that electromagneticfield responsive gels can be used for severalapplications, such as microcapsules of colourants ormedicines, mechanico-chemical memories or switches,sensors, actuators, transducers, memories, controlledrelease Systems and sélective pumps.

The known applications are confined to surfaceequipment and usé in relatively small mechanicalassemblies which are operated in a controlledenvironment.

However, applicant has surprisingly discovered thatsuch gels can be applied in a downhole flow controldevice which opérâtes at high pressure and température ina well. The gels can be actuated by an electromagneticfield which is between 0.5 and 50 Volt per cm length ofthe déformable chamber so that the required power issmall in comparison with mechanical valves and can easilybe generated by a downhole battery, power cell, powergenerator and/or transmitted via the wall of the welltubulars.

It is preferred that the gel is contained in aflexible bladder which seals off the fluid passage inresponse of a volume increase of at least part of the gelin the chamber. 3 118 7 8

Suitably, the flexible bladder has a toroidal shapeand surrounds an orifice in a production liner in theinflow région of an oil and/or gas production well andwherein the gel in the flexible bladder is induced toswell so that the bladder seals off the orifice inresponse to the détection of influx of water into thewell via the orifice.

Alternatively, the flexible bladder has a toroidalshape and is arranged in an annular space between two co-axial production tubing sections of which the walls areperforated near one end of the annular space such thatthe perforations are closed off in response to a volumeincrease of at least part of the body of gel within thebladder and the perforations are opened in response to avolume decrease of at least part of the body of gelwithin the bladder.

It is observed that International patent applicationWO 97/0330 discloses a drilling composition includingnon-polyampholite polymers and gels which change theirState of hydration in response to an environmentaltrigger.

The know drilling composition selectively blocks thepores of the stratum surrounding the wellbore andtherefore relates to treatment of a stratum outside thewellbore in contrast with the présent invention whichrelates to a downhole flow control device which isarranged inside a wellbore.

Description of preferred embodiment

The invention will be described in more detail withreference to the accompanying drawings in which:

Fig. IA shows a device according to the inventionwith a gel-filled bladder in the open position;

Fig. IB shows the device of Fig. IA where the gel-filled bladder closes off the fluid passage; 4 118 7 8

Fig. 2A shows an alternative embodiment of the deviceaccording to the invention in the open position thereof;

Fig. 2B shows the device of Fig. 2A in the closedposition thereof;

Fig. 3A shows yet another embodiment of the deviceaccording to the invention in the open position thereof;

Fig. 3B shows the device of Fig. 3Ά in the closedposition;

Figs. 4A and 4B are schematic top- and three-dimensional views of slight modifications of the deviceof Figs. 3A and 3B;

Fig. 5 shows a schematic cross-sectional view of thedevice according to Figs. 4A and 4B in a well tubular;and

Fig. 6 is a three-dimensional view of the welltubular of Fig. 5 in which a plurality of devicesaccording to the invention are embedded.

Referring now to Figs. IA and IB there is shown anoil and/or gas production well 1, which traverses an oiland/or gas bearing formation 2. A well liner 3 provides a lining of the wellbore andperforations 10 in the liner 3 allow oil and/or gas toflow into the well 1 from the surrounding formation. A sleeve 4 is removably secured within the well liner3 by means of a pair of inflatable packers 5.

The sleeve 4 comprises an annular space 6 which isformed between an inner and an outer wall 7 and 8 of thesleeve 4 and at the right-hand side of the drawing theannular space 6 both the inner and outer walls of thesleeve comprise perforations 9. A gel-filled bladder 11 is arranged in the annularspace 6. The bladder 11 comprises two segments 11A and11B which are separated by a bulkhead 12. The bulkhead 12is permeable to water, but imperméable to the 5 1187 8 electromagnetic field responsive gel 13 in the bladder 11.

The sleeve 4 is equipped with a rechargeablebattery 14 and an electrical power receiver and/ortransmitter assembly 15 which are adapted to exert anelectric field to either the first or the secondsegment 11 or 11B, respectively of the bladder.

In Fig. IA the electromagnetic field is exerted tothe first segment 11A and water is squeezed out of thegel 13 contained therein through the bulkhead 12 into thesecond segment 11B in which the gel 13 absorbs water. Asa resuit the bladder 11 is pushed to the right hand sideof the drawing and closes off the perforations 9 so thatinflux of fluids into the interior of the sleeve 4 isprevented. Pressure balancing conduits 17 allow a freemovement of the bladder segments 11A and 11B through theannular space 6.

In Fig. IB the electromagnetic field is exerted tothe second segment 11B and water is then squeezed fromthe gel 13 contained therein into the first segment 11Aso that the bladder moves to the left and allows wellfluids to flow via the perforations 9 and 10 from theformation 2 into the well 1.

Fig. 2 shows a device substantially similar to thatof Fig. 1 and in which similar reference numerals dénotésimilar components, with the exception that in thebladder two water-permeable bulkheads 12A and 12B arearranged between which a body of free water 16 is présentto facilitate water to flow easily between the segments 11A and 11B.

Fig. 2A shows the device in the open position andFig. 2B in the closed position.

Referring to Figs. 3A and 3B there is shown anotherembodiment of the downhole fluid flow control device 6 1187 8 according to the invention which can, as shown in Fig. 6,be embedded in an opening of a well tubular.

Fig. 3A shows the device 30 in the open position sothat fluid is permitted to flow into the well as shown byarrow 31.

The device 30 comprises a disk-shaped housing 32, inwhich a disk-shaped cavity 33 is présent. A toroidal bladder 34 is mounted in the housing 32such that a central opening 33 in the bladder 34 isaligned with a central fluid passage 36 in thehousing 32. A sandscreen 37 is arranged at the entranceof the fluid passage 36 to prevent influx of sand andother solid particles into the well.

The bladder 34 is surrounded by a toroidal body offoam 38 of which the pores are filled with water. Thefoam also contains cells or granules that are filled withan expandable gas. The bladder 34 is filled with anelectromagnetic field responsive gel 39 and has acylindrical outer wall 40 which is permeable to water butimperméable to the gel 39.

An electrical coil 41 is embedded in the body offoam 38. The coil 41 forms part of an electricalcircuit 42 which comprises an electric switch 43 and anelectrical source 44 in the form of an in-siturechargeable battery. The battery may be powered bypassing a low voltage electrical current through the wallof the well tubulars and/or by a downhole electricalpower generator (not shown) which is driven by a smallfan or turbine which is itself rotated by the fluid flowthrough the well.

In Fig. 3A the switch 43 is open so that noelectrical current flows through the coil 41. As a resuitno electromagnetic field is exerted to the gel 39 and thegel will release water which trickles through the waterpermeable outer wall 40 of the bladder 34 and is absorbed 118 7 8 7 by the foam 38. This causes the gel 38 to shrink so thatthe bladder 34 contracts towards the cylindrical outerwall 40 thereof and a central opening 35 is createdthrough which fluids are permitted to flow into the wellas indicated by arrow 31.

In Fig. 3B the switch 43 is closed so that t-heelectrical coil 41 induces an electromagnetic field tothe gel 39. As a resuit the gel 39 will absorb water fromthe foam 38 via the cylindrical outer wall 40 of thebladder 34. This causes the gel 39 to swell so that thebladder 34 expands and thereby closes off the centralfluid passage 36.

The switch 43 may be connected to a downhole sensor(not shown) which closes the switch if an influx of waterthrough the device is detected. The sensor may also formpart of a sensor assembly which monitors a range ofparameters and which is connected to a data processingunit that is programmed to optimize the production ofhydrocarbon fluids from the réservoir.

Figs. 4A and 4B show an embodiment of a deviceaccording to the invention in which the housing 50 has anoblong or elliptical shape. As illustrated in Fig. 4A inthat case the gel filled bladder 51 may be separated froma pair of bodies of water filled foam 52 by a pair ofwater permeable bulkheads 53. The central fluid passagemay hâve a cylindrical or elliptical shape and contain asandscreen 54 and the electric coil (not shown) isembedded in the housing 50.

Fig. 5 is a cross-sectional view of the device ofFigs. 4A and 4B which is embedded in the wall of a welltubular 55. Fig. 6 is a three-dimensional view of thewell tubular 55 of Fig. 5 in which a pair of inflowcontrol devices as shown in Figs. 4A, 4B and 5 areembedded. 8 118 7 8

The housings 50 of the devices shown in Fig. 6 areoriented in a longitudinal direction with respect to thewell tubular to allow that the housings 50 hâve asubstantially fiat shape which simplifies the 5 manufacturing process.

It will be understood that the gel filled bladder mayhâve a water permeable wall which is in contact with wellfluids and which allows the gel to absorb and releasewater from and into the well fluids. In such case the 10 wall of the bladder should be permeable to water, but imperméable to the gel and produced oil and/or gas.

It will also be understood that the electromagneticfield responsive gel may be replaced by another stimuliresponsive gel such as a température responsive gel and 15 that the bladder may be replaced by another déformable chamber, such as a cylindrical chamber where the gelinduces a piston to move up and down in response tovariations of the volume of the gel.

Claims (10)

1. 9 118 7 8 C L A I M S

   1. A downhole device for controlling the flow of fluidsthrough a hydrocarbon fluid production well, the devicecomprising a déformable chamber which contains a stimuliresponsive gel, which gel has a volume that varies inresponse to variation of a selected physical stimulatingparameter, the device further comprising a fluid passagewhich is closed off in response to a volume increase ofat least part of the gel and the déformable chamber.
2. 2. The device of claim 1, wherein the gel is an electromagnetic field responsive gel which releases waterif an electromagnetic field of a certain field strengthis exerted to the gel and which absorbs water in theabsence of an electromagnetic field and wherein thedevice is equipped with an electromagnetic fieldtransmitter which is adapted to exert an electromagneticfield of a selected field strength to the gel.
3. 3. The device of claim 2, wherein the gel is selectedfrom the group of polyacrylamide gels and polymethyl-acrylic acid gels.
4. 4. The device of claim 1, wherein the gel is containedin a flexible bladder which seals off the fluid passagein response of a volume increase of at least part of thegel in the chamber.
5. 5. The device of claim 4, wherein the flexible bladderhas a toroidal shape and surrounds an orifice in aproduction liner in the inflow région of an oil and/orgas production well and wherein the gel in the flexiblebladder is induced to swell so that the bladder seals offthe orifice in response to the détection of influx ofwater into the well via the orifice. 10 118 7 8
6. 6. The device of claim 4, wherein the flexible bladderhas a toroidal shape and is arranged in an annular spacebetween two co-axial production tubing sections of whichthe walls are perforated near one end of the annularspace such that the perforations are closed off inresponse to a volume increase of at least part of thebody of gel within the bladder and the perforations areopened in response to a volume decrease of at least partof the body of gel within the bladder.
7. 7. The device of claim 5, wherein the flexible bladdercomprises two segments which are separated by at leastone bulkhead which is imperméable to the gel and which isat least temporarily permeable to water.
8. 8. The device of claim 7, wherein said at least onebulkhead is made of a material which is permeable towater if an electromagnetic field is imposed on thebulkhead and which is imperméable to water if noelectromagnetic field is éxerted to the bulkhead.
9. 9. The device of claim 8, wherein said at least onebulkhead séparâtes two segments of the flexible bladderwhich each comprise a gel according to claim 2 or 3 andthe device comprises one or more electromagnetic sourceswhich are adapted to selectively impose an electromagnetic field on one of the segments of thechamber and/or the bulkhead.
10. 10. The device of claim 7, wherein the flexible bladdercomprises two gel-filled segments which are separated bya pair of gel imperméable bulkheads which are separatedby an intermediate segment of the chamber which is filledwith water.