WO2018184093A1

WO2018184093A1 - Methods and apparatuses for steam injection in wellbores for hydrocaron recovery

Info

Publication number: WO2018184093A1
Application number: PCT/CA2018/000067
Authority: WO
Inventors: Serhiy Arabskyy; Andrew BARABASH
Original assignee: Interra Energy Services Ltd.
Priority date: 2017-04-04
Filing date: 2018-04-03
Publication date: 2018-10-11

Abstract

An apparatus is disclosed for injecting steam into a wellbore that may comprise an outer casing section for lining a portion of the wellbore and forming a portion of the casing string, and a steam dispersion device that may include an inner tubing disposed in the outer casing section bore and defining an inner tubing bore. The steam dispersion device may be sealingly coupled to the outer casing section prior to the apparatus being disposed in the wellbore, such that, when the outer casing section is coupled in-line with the adjacent portion of the casing string in the wellbore, the apparatus permits steam communication between the casing string bore of the adjacent portion of casing string and the wellbore via the inner tubing bore, inner tubing radials openings, an annulus between the outer casing section and the inner tubing, and outer casing section radial openings.

Description

METHODS AND APPARATUSES FOR STEAM INJECTION IN WELLBORES FOR

HYDROCARON RECOVERY

CROSS REFERENCE TO RELATED APPLICATIONS: The present application claims priority to U.S. Provisional Patent Application

Serial No. 62/481 ,260 filed April 4, 2017, the entire contents of which is hereby expressly incorporated herein by reference.

TECHNICAL FIELD:

The present disclosure relates to steam injection in wellbores, including in particular steam injection for SAGD operations for recovery of hydrocarbons.

BACKGROUND:

Steam Assisted Gravity Drainage (SAGD) is a method for recovering viscous oil and bitumen from underground heavy oil deposits. During a SAGD process, two vertically spaced apart, coextensive horizontal wells are drilled close to the base of a viscous oil or bitumen deposit. A steam generator located at the surface of the steam injection well generates and injects steam down a steam tubular, which is run downhole in the wellbore casing. The steam is released from the steam tubular through exit ports, flows into the steam injection wellbore (the upper wellbore) and moves outward into the formation. The injected steam forms a steam chamber which heats the formation, and thereby reduces the viscosity of the oil and increases its mobility. This allows the heated oil to drain downwardly, through the force of gravity, towards the production wellbore (the lower wellbore). The production well is opened so that it can collect the draining liquid.

Figure 1 shows a conventional steam injection well of a SAGD system with a tubing deployed steam injection control device located within a slotted liner. For example, a casing having a diameter of about 7.5 inches (19 cm) is run into the wellbore prior to running the steam tubular having a diameter of about 4.5 inches (1 1 cm) and associated steam injection tool downhole within the casing. This requires a substantial amount of time before production operations can begin. Further, the steam tubular and steam injection tool may be inadvertently damaged when being run downhole into the casing. Further still, the steam tubular and steam injection tool reduces the cross-sectional flow area of the casing, thus limiting the production rate from the well and creating pressure drops across the casing (for example, where the well also serves as a production well relative to another well). Further still, the steam injection tubular is prone to breakage and/or cracking due to thermal cycling. If broken, the steam will escape through a crack in the steam injection tubular as opposed to through the steam injection tool, and not be distributed through the wellbore as intended.

SUMMARY:

Objects of the present disclosure can include saving time and cost associated with completing steam injection wells, reducing the risk of damage to steam injection equipment, and optimizing the capacity of steam injection wells. In one aspect, the present disclosure provides an apparatus for injecting steam from a casing string bore of a casing string into a wellbore. The apparatus includes an outer casing section, and a steam dispersion device.

The outer casing section is for lining a portion of the wellbore and for coupling inline with an adjacent portion of the casing string to form part of the casing string. The outer casing section defines an outer casing section bore.

The steam dispersion device includes an inner tubing disposed in the outer casing section bore to define an annulus between the inner tubing and the outer casing section. The inner tubing defines an inner tubing bore for steam communication with the casing string bore of the adjacent portion of casing string.

The steam dispersion device is sealingly coupled to the outer casing section prior to the apparatus being disposed in the wellbore, such that, when the apparatus is disposed in the wellbore with the outer casing section coupled inline with the adjacent portion of the casing string and the inner tubing bore in steam communication with the casing string bore of the adjacent portion of the casing string, the apparatus permits steam communication between the casing string bore of the adjacent portion of casing string and the wellbore only via at least one inner tubing radial opening for steam communication between the inner tubing bore and the annulus, and at least one outer casing section radial opening for steam communication between the annulus and the wellbore.

In embodiments, the inner tubing comprises a plurality of portions removably attached to each other. In embodiments, the steam dispersion device includes a moveable member that is disposed in the outer casing section bore. The moveable member is movable relative to the at least one inner tubing radial opening to vary an open area of the inner tubing radial opening and thereby control steam communication between the inner tubing bore and the annulus. In embodiments, the movable member is a sleeve slideably disposed within the inner tubing bore.

In embodiments, the apparatus further includes at least one coupler. In embodiments, the apparatus can include a first coupler for coupling the steam dispersion device to the outer casing section. In other embodiments, the apparatus further includes a second coupler for coupling the outer casing section inline with the adjacent portion of the casing string. In some embodiments, the at least one coupler comprises: an outer connection for connecting the coupler to the outer casing section; an inner connection for connecting the coupler to the inner tubing; and a casing connection for connecting the coupler to the adjacent portion of the casing string; and the coupler defines a coupler bore for steam communication from the casing string bore of the adjacent portion of the casing string to the inner tubing bore.

In embodiments, the at least one coupler comprises: an uphole coupler for coupling the outer casing section inline with an adjacent uphole portion of the casing string; and a downhole coupler for coupling the outer casing section inline with an adjacent downhole portion of the casing string. In embodiments, the annulus has a radial dimension as measured between the outside diameter of the inner tubing and the inside diameter of the outer casing section of equal or less than about 10 mm.

In another aspect, the present disclosure provides a method for completing a casing string for injecting steam into a wellbore. The method includes the steps of:

(a) coupling the outer casing section of the apparatus described above inline with an adjacent portion of the casing string to form a part of the casing string, with the inner tubing bore of the apparatus in steam communication with a casing string bore of the adjacent portion of the casing string; and

(b) running the part of the casing string downhole into the wellbore.

In another aspect an apparatus is provided that is operable to be installed inline with an adjacent downhole portion of a casing string to form a part of the casing string. The apparatus comprises: (a) an outer casing section comprising an outer section bore, the outer casing section operable to line a portion of a wellbore and be coupled in-line with the adjacent downhole portion of the casing string when the casing string is deployed in the wellbore; (b) a steam dispersion device located within the outer section bore of the outer casing section, the steam dispersion device operable to disperse steam through the outer casing section into the wellbore when the casing string is deployed in the wellbore and the outer casing section is coupled in-line with the adjacent downhole portion of the casing string; and (c) at least one coupling mechanism operable to couple the apparatus in-line with the adjacent downhole section of the casing string.

The steam dispersion device may be coupled by at least one coupling mechanism to the outer casing section. The steam dispersion device may be sealingly coupled to the outer casing section, such that when the casing string is in the wellbore and the outer casing section is coupled in-line with the adjacent downhole portion of the casing string, the steam dispersion device is in communication with steam supplied from the adjacent downhole portion of the casing string. The steam dispersion device may comprise an inner tubing with an inner tubing bore in communication with steam supplied from the adjacent downhole portion of the casing string and have at least one opening operable to communicate steam to the outer casing section for dispersion into the wellbore; and wherein the at least one coupling mechanism may comprise a coupler that is operable to provide: (i) an outer connection operable for sealing connection with the outer casing section; (ii) an inner connection operable for sealing connection with the inner tubing; and (iii) a third connection operable for connecting to the adjacent downhole portion of the casing string; and wherein the coupler provides a coupler bore for communication of steam supplied from the adjacent downhole portion of the casing string to the inner tubing bore. In another aspect an apparatus is provided that is operable to be installed inline with adjacent uphole and downhole sections of a casing string to form a part of the casing string. The apparatus comprises:(a) an outer casing section comprising an outer section bore; (b) a steam dispersion device located within the outer section bore comprising an inner tubing defining an annulus between the inner tubing and outer casing section, the inner tubing comprising an inner tubing bore and a plurality of inner tubing radial openings arranged along a length of the inner tubing; and (c) a first coupler and a second coupler for coupling the apparatus in-line with the adjacent up-hole and downhole sections of the casing string, wherein the first coupler is located at a downhole end of the apparatus and the second coupler is located at an up-hole end of the apparatus.

The outer casing section may further comprise at least one outer casing section radial opening. The outer casing section may further comprise a permeable material disposed about an exterior area of the outer casing section. The inner tubing may comprise an inner tubing up-hole portion, an intermediate portion, and a downhole portion. A plurality of inner tubing radial openings may be arranged in multiple rows along the length of and circumferentially around the intermediate portion. The steam dispersion device may further comprise a moveable member wherein the moveable member is movable relative to the plurality of inner tubing radial openings. The moveable member may be a sliding sleeve. The apparatus may further comprise a latching mechanism to secure the moveable member in a plurality of positions. The first coupler may be a dual coupler comprising an outer connection for sealing connection with the outer casing section, an inner connection for sealing connection with a downhole portion of the inner tubing, and a downhole casing connection for sealing connection with the downhole section of the casing string. The second coupler may be an expansion coupler comprising an outer connection for sealing connection with the outer casing section, an inner connection for sealing connection with an up-hole portion of the inner tubing, and an up-hole casing connection for sealing connection with the up-hole section of the casing string. In another aspect an apparatus is provided for injecting steam from a casing string bore of a casing string into a wellbore, the apparatus comprising: (a) an outer casing section for lining a portion of the wellbore and for coupling in-line with an adjacent portion of the casing string to form part of the casing string, wherein the outer casing section defines an outer casing section bore; and (b) a steam dispersion device comprising an inner tubing disposed in the outer casing section bore to define an annulus between the inner tubing and the outer casing section, wherein the inner tubing defines an inner tubing bore for steam communication with the casing string bore of the adjacent portion of casing string. The steam dispersion device is sealingly coupled to the outer casing section prior to the apparatus being disposed in the wellbore, such that, when the apparatus is disposed in the wellbore with the outer casing section coupled in-line with the adjacent portion of the casing string and the inner tubing bore in steam communication with the casing string bore of the adjacent portion of the casing string, the apparatus permits steam communication between the casing string bore of the adjacent portion of casing string and the wellbore only via at least one inner tubing radial opening for steam communication between the inner tubing bore and the annulus, and at least one outer casing section radial opening for steam communication between the annulus and the wellbore.

The steam dispersion device may comprise a moveable member movable relative to the at least one inner tubing radial opening to vary an open area of the inner tubing radial opening and thereby control steam communication between the inner tubing bore and the annulus. The apparatus may further comprise a first coupler for coupling the steam dispersing device to the outer casing section. The apparatus may also further comprise a second coupler for coupling the outer casing section in-line with the adjacent portion of the casing string. The apparatus may further comprising at least one coupler, each of the at least one coupler comprising: (i) an outer connection for connecting the coupler to the outer casing section; (ii) an inner connection for connecting the coupler to the inner tubing; and (iii) a casing connection for connecting the coupler to the adjacent portion of the casing string; wherein the coupler defines a coupler bore for steam communication from the casing string bore of the adjacent portion of the casing string to the inner tubing bore.

The apparatus may further comprise: an up-hole dual coupler for coupling the outer casing section in-line with an adjacent up-hole portion of the casing string; and a downhole dual coupler for coupling the outer casing section in-line with an adjacent downhole portion of the casing string. The inner tubing may comprise a plurality of portions removably attached to each other. The movable member may be a sleeve slideably disposed within the inner tubing bore. The annulus may have a radial dimension as measured between an outside diameter of the inner tubing and an inside diameter of the outer casing section of equal or less than about 10 mm.

In another aspect a method is provided for completing a casing string for injecting steam into a wellbore, the method comprising: (a) coupling the outer casing section of any apparatus referenced above in-line with an adjacent portion of the casing string to form a part of the casing string, with the inner tubing bore of the apparatus in steam communication with a casing string bore of the adjacent portion of the casing string; and (b) running the part of the casing string downhole into the wellbore. Step (a) may be performed a plurality of times.

In another aspect an apparatus is provided that comprises a completed casing string for injecting steam into a wellbore produced according to the methods referenced immediately above. In another aspect there is provided a method for injecting steam into a wellbore comprising transferring steam through such a casing string.

In another aspect is provided the use of any of the apparatuses referenced above to inject steam into a wellbore. In another aspect is provided the use of any of the apparatuses referenced above to recover hydrocarbons from a subterranean formation in a steam assisted gravity drainage operation.

BRIEF DESCRIPTION OF THE DRAWINGS:

Exemplary embodiments of the present disclosure are described with reference to the following drawings. In the drawings, like elements are assigned like reference numerals. The drawings are not necessarily to scale, with the emphasis instead placed upon the principles of the present disclosure. Additionally, each of the embodiments depicted is but one of a number of possible arrangements utilizing the fundamental concepts of the present disclosure. The drawings are briefly described as follows:

Figure 1 is a diagram of a prior art steam injection system;

Figures 2A and 2B are side cross-sectional views of an embodiment of an apparatus of the present disclosure for the injection of steam into a hydrocarbon well in a closed and open position, respectively;

Figure 3 is an enlarged scale view of an intermediate portion of Figure 2B;

Figure 4 is an enlarged scale view of the downhole portion of Figures 2A and

2B; Figure 5 is an enlarged scale view of the uphole portion of Figures 2A and 2B; Figures 6A and 6B are side cross-sectional views of another embodiment of an apparatus of the present disclosure for the injection of steam into a hydrocarbon well in a closed and open position, respectively; and

Figure 7 is a side cross-sectional view of an exemplary embodiment of a well comprising an exemplary embodiment of an apparatus of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS:

In exemplary applications, the apparatus and method of the present disclosure may be used for Steam Assisted Gravity Drainage (SAGD) operations to recover hydrocarbons from subterranean formations. Any term or expression not expressly defined herein shall have its commonly accepted definition understood by a person skilled in the art. It should be understood that terms such as top, bottom, upper, lower, downhole and uphole are relative terms used for convenience only.

As used herein, the terms "couple", "coupled", "coupling", and like terms in describing the relationship between two parts, includes the two parts being directly connected to each other so as to be in contact with each other, as well as the two parts being indirectly connected to each other without being in contact with each other. Further, it will be understood that two parts may be coupled by a variety of connection mechanisms, including without limitation, threaded connections, frictional interference fit mechanisms (e.g., elastomeric seals, and snap rings), welded connections, crimp connections, connections whereby one part bears against another (e.g., by use of shoulders formed on the parts), and packers that are actuated by mechanical and/or hydraulic means, or by swelling upon contact with wellbore fluids.

Overview of apparatus With reference to Figures 2A and 2B, an exemplary embodiment of an apparatus 10 of the present disclosure comprises an outer casing section 12, an inner tubing 19, a moveable member 20, a downhole dual coupler 40 and an uphole dual coupler 50. The inner tubing 19 and the moveable member 20 collectively form a steam dispersion device. The exemplary embodiment of the apparatus of the present disclosure shown in Figures 6A and 6B, is similar to the exemplary embodiment of the apparatus shown in Figures 2A to 5 with one difference being the size of the proportions of the annulus 15. Accordingly, the following description of the embodiment of the apparatus shown in Figures 2A to 5 applies equally to the embodiment of the apparatus shown in Figures 6A and 6B, with like elements assigned like reference numerals.

In an exemplary use, as shown in Figure 7, the apparatus 10 of the present disclosure can be installed inline in a steam injection line 120 with adjacent uphole and downhole sections of a casing/lining string, in substitution for a portion of the casing/lining string and the steam injection tubing of a conventional steam injection well, such as shown in Figure 1 . The steam injection line 120 may run generally parallel to a retrieval line.121 as shown in Figure 7 Outer casing section

The outer casing section 12 is for lining a portion of the wellbore. The outer casing section 12 is also for coupling inline with an adjacent portion of the casing string to form part of the casing string. The outer casing section 12 defines an outer casing section bore 1 1 . The outer casing section 12 can be similar to wellbore casing or liner used in the rest of the casing string.

In an exemplary embodiment, the outer casing section 12 defines at least one outer casing section radial opening (not shown) (e.g., one or more apertures or slots spaced about outer casing section 12) for steam communication between the annulus 15 (as described below) and the wellbore. Examples of suitable holed or slotted casings that may be used for the outer casing section 12 are available from National Oilwell Varco Elmar (Aberdeen, Scotland).

In exemplary embodiments, a fine, permeable material designed to allow steam from the outer casing section bore 1 1 to flow into the wellbore formation, but prevent debris from entering the outer casing section bore 1 1 can be disposed about the exterior of outer casing section 12. Examples of such materials are MeshRite™ filtration screen (Absolute Completion Technologies, Calgary, Canada).

Steam dispersion device

The steam dispersion device allows for the injection of steam from the casing string into the wellbore. The steam dispersion device is located within the outer casing section bore 1 1 . In embodiments, the steam dispersion device may also include a moveable member 20 to control steam communication through the openings 30 by varying an open area of the openings 30. As used herein "varying an open area of the openings" and like expressions includes any change in the area of one or more openings through which steam communication is permitted, and includes changing the open area to part of the area of the openings (30) (i.e., a partially open state), as well as fully closed and fully open states.

In the exemplary embodiment, the steam dispersion device includes the inner tubing 19 and the movable member 20, as further described below. In other embodiments, the steam dispersion device may not include the moveable member 20. Inner tubing

The inner tubing 19 is disposed in the outer casing section bore 1 1 to define an annulus 15 between the inner tubing 19 and the outer casing section 12. The inner tubing 19 defines an inner tubing bore 18, and at least one inner tubing radial opening 30 for steam communication from the inner tubing bore 18 to the annulus 15.

In the exemplary embodiment shown in the Figures, the inner tubing 19 comprises an inner tubing uphole portion 13, intermediate portion 16, and downhole portion 14. The intermediate portion 16 is connected to uphole and downhole portions 13, 14 via fluid-tight threaded connections or other suitable means known in the art so as to form a continuous inner tubing bore 18. The intermediate portion 16 defines a plurality of inner tubing radial openings 30 that are arranged in multiple rows along the length of and circumferentially around the intermediate inner tubing portion 16.

In the exemplary embodiment shown in the Figures, the inner tubing 19 is dimensioned such that the inside diameter of the inner tubing bore 18 comprises a substantial majority of the inside diameter of the outer casing section bore 1 1 . In this manner, the production capacity of the inner tubing 19 is almost equal to that of the outer casing section 12. Further, the radial dimension of the annulus 15 (as measured between the outside diameter of the inner tubing 19 and the inside diameter of the outer casing section 12) is relatively small such as, for example, in the range of about 4 mm to about 10 mm. It will be appreciated, however, that in other embodiments, the radial dimension of the annulus may be outside of this range of sizes without departing from the principles of the present invention.

The inner tubing 19 may be formed from a single tubing member rather than multiple detachable portions 13, 14, and 16. However, the use of multiple detachable portions 13, 14, 16 allows the intermediate portion 16 and associated moveable member 20 to be combined with uphole and downhole portions 13, 14 of different selected lengths. In this manner, openings 30 can be located at a desired location along the outer casing sections 12, and the intermediate portion 16 and associated moveable member 20 can be used with different standardized lengths of outer casing sections 12. For example, in an exemplary embodiment, the outer casing section 12 has a length of 20 feet, and the intermediate portion 16 has a length of 2 feet. The tubing portions 13, 14 are selected to have a combined length of 18 feet such that the inner tubing 19 as a whole and the outer casing section 12 have the same length. In further exemplary embodiments, inner tubing 19 can include a plurality of portions (like intermediate portions 16) that define openings 30, which portions can be positioned at different parts of the inner tubing 19 to allow for multiple points of entry into the annulus 15. This again allows for better control of location and flow of (dispersion) of steam between the inner bore 18 and the annulus 15.

In the exemplary embodiment shown in the Figures, multiple shrouds 32 are disposed on an exterior surface of intermediate portion 16 over the inner tubing radial openings 30 so as to control the flow of steam passing from inner tubing bore 18 into annulus 15. For example, in the exemplary embodiment shown in the Figures, the shrouds 32 are configured to direct steam into portions of the annulus 15 that are relatively uphole and downhole of the inner tubing radial openings 30.

Moveable member The moveable member 20 is movable relative to the inner tubing radial openings 30 to vary an open area of the openings 30 and thereby control steam communication between the inner tubing bore 18 and the annulus 15.

In the exemplary embodiment shown in the Figures, the moveable member 20 is in the form of a sliding sleeve 20 disposed within the intermediate portion 16. The sleeve 20 can be actuated between a closed position (Figure 2A) and an open position (Figure 2B). In the closed position (Figure 2A), sealing elements 24 located on the outer surface of the sleeve 20 straddle the openings 30, such that at least one sealing element 24 is located uphole from the one or more openings 30 and one sealing element is located downhole from the one or more openings 30, thereby preventing steam in the inner tubing bore 18 from being released into the annulus 15 and subsequently the hydrocarbon formation. Thus, when the sleeve 20 is in the closed position, the open area of the openings 30 is varied to nil.

In the open position (Figure 2B), sealing elements 24 are located downhole from the one or more openings 30, thereby exposing the openings 30 to the inner tubing bore 18 and permitting steam communication between the inner tubing bore 18 and the annulus 15. Thus, when the sleeve 20 is in the open position, the open area of the openings 30 is varied to the area of the openings 30.

In other embodiments (not shown), the orientation of the intermediate portion 16 and the sleeve 20 can be inverted. That is, the sleeve can be shifted such that sealing elements 24 are located uphole from the one or more openings 30 to establish fluid communication between inner tubing bore 18 and annulus 15.

In embodiments, the apparatus 10 may include a latching mechanism to secure the moveable member 20 in a plurality of positions such that the open area of openings 30 are in various states of opening (e.g., fully open, partially open, or fully closed). In the exemplary embodiment shown in Figure 3, for example, a system of grooves and clips cooperate to secure the sleeve 20 in fully open and fully closed positions. First and second circumferential grooves 26, 27 are formed on the inner surface of the intermediate portion 16. A plurality of resilient clips 21 are attached to and spaced circumferentially about the sleeve 20. Each of the plurality of clips 21 have a radially outwardly extending shoulder 22, which is shaped and sized to form an interference fit with the inner surface of the intermediate portion 16, and to complement the shape of circumferential grooves 26, 27. When in the closed position (Figure 2A), shoulders 22 are seated in first groove 26 such that the sleeve 20 does not move axially unless a threshold force is overcome to unseat the shoulders 22 from groove 26 by bending clips 21 radially inward. Likewise, when in the open position, shoulders 22 are seated in second groove 27 to prevent axial movement of sleeve 20 unless a threshold force is overcome. The upper and lower edges of shoulders 22 can be angled, rounded, or otherwise shaped to facilitate the radially inward bending of clips 21 when sufficient axial force is applied to the sleeve to overcome the threshold force.

It will be understood that the openings 30 and the moveable member 20 effectively form a valve assembly for controlling steam communication between the inner tubing bore 18 and the annulus 15. In other embodiments (not shown), the moveable member 20 may assume a form other than a sleeve 20, and may move relative to the openings 30 in manners other than sliding. In other non-limiting examples (not shown), the moveable member 20 may move relative to the openings 30 by one or a combination of longitudinal or radial translation, or rotation relative to the inner tubing 19. As still further non-limiting examples, the moveable member 20 may comprise an obturator such as a dart, or ball, that moves to partially or fully cover the openings 30. As still further non-limiting examples, the moveable member 20 may comprise a burst disc or burst plug valve that occludes the openings 30, and ruptures when subjected to a threshold pressure to expose the openings 30.

In other embodiments (not shown), for example, when inner tubing 19 includes a plurality of portions (like intermediate portions 16) that define openings 30, each of the plurality of portions can have a corresponding movable member 20. Alternatively, one movable member 20 can correspond to two or more of the plurality of portions, or even all of the plurality of portions, such that a single movable member 20 varies the open area of the openings 30 of multiple portions . In other embodiments (not shown), the steam dispersion device may include any suitable device known in the art comprising an inner tubing 19 defining an inner tubing bore 18 and at least one inner tubing radial opening 30 for steam communication from the inner tubing bore 19 to the annulus 15. Non-limiting examples of steam dispersion devices that may be adapted for use with the present invention are disclosed in United States Patent no. 7,631 ,694 B2 (Struyk et al.), Canadian Patent no. 2,765,812 C (Waterhouse et al.), PCT International Application Publication WO2015/026340 (Gano), and PCT International Application Publication WO20 5/176158 A1 (Arabsky et al.), the contents of which are incorporated by reference where permitted. Suitable steam dispersion devices may be referred to by persons in the art as "steam splitters". However, in contrast to the teachings of the prior art references, it will appreciated that such prior art steam dispersion devices will be adapted for use with the present disclosure by being connectable to the outer casing section 12, rather than connectable to a steam tubing that is inserted into a casing that has already been inserted into a wellbore.

Couplers

The couplers 40, 50 couple the apparatus 10 inline with an adjacent downhole portion and uphole portion, respectively, of the casing string. Further, the couplers 40, 50 also directly or indirectly couple the outer casing section 12 to the inner tubing 19. Further still, the couplers 40, 50 permit steam communication between the adjacent downhole portion and uphole portions, respectively, of the casing string and the inner tubing bore 18. At the same time, the couplers 40, 50 prevent steam communication directly between the adjacent uphole and downhole portions of the casing string and the annulus 15, except via the inner tubing bore 18 and the inner tubing radial openings 30.

In the exemplary embodiment shown in Figure 4, the coupler 40 is a dual coupler located at the downhole end 8 of the apparatus 10 to connect the apparatus 10 to an adjacent downhole portion of a casing string (not shown). In the exemplary embodiment, the dual coupler 40 supports the weight of the steam injection assembly and prevents rotation thereof during production operations. Dual coupler 40 comprises an outer connection 42 for sealing connection with outer casing section 12, an inner connection 44 for sealing connection with the downhole portion 14, and a downhole casing connection 46 for sealing connection with the downhole portion of the casing string. Connections 42, 44, 46 can be threaded connections. One or more sealing elements (not shown) can be provided for forming a fluid-tight seals at each of the connections 42, 44, 46. The dual coupler 40 defines a coupler bore that permits steam communication between the downhole portion of the casing string connected to the downhole portion 14.

In the exemplary embodiment shown in Figure 5, coupler 50 is an expansion coupler located at the uphoie end 6 of the apparatus 10 to connect the apparatus 10 to an adjacent uphoie portion of a casing string (not shown). Expansion coupler 50 comprises an outer connection 52 for sealing connection with the outer casing section 12, an inner connection 54 for sealing connection with the uphoie portion 13, and an uphoie casing connection 58 for sealing connection with the adjacent uphoie portion of the casing string. The outer connection 52 and uphoie casing connection 58 can be a threaded connection with sealing elements in the same manner as the outer connection and downhole casing connection of dual coupler 40. Inner connection 54 of expansion coupling 50 can have one or more sealing elements 56 disposed on its inner surface for frictionally coupling with the uphoie portion 13. The frictional coupling allows the inner tubing 19 to expand or contract (e.g., due to temperature changes) within the inner connection 54.

Accordingly, with the use of couplers 40, 50, it will be understood that the steam dispersion device is sealingly coupled to the outer casing section 12 prior to the apparatus 10 being disposed in the wellbore. Further, when the apparatus 10 is disposed in the wellbore with outer casing section 12 coupled inline with the adjacent downhole and uphoie portions of the casing string and the inner tubing bore 18 in steam communication with the adjacent downhole and uphoie portions of the casing string, the apparatus permits steam communication between the casing string bore of the adjacent downhole and uphole portions of casing string and the wellbore only via inner tubing bore 18, inner tubing radial openings 30, annulus 15, and the outer casing section radial opening(s). In other embodiments (not shown), the couplers 40, 50 may comprise one or more separate or integral components for forming direct or indirect connections between the outer casing section 12, the casing string, and the inner tubing 19. For example, a first coupler may be used to couple the outer casing section 12 to the casing string, while a separate second coupler may be used to couple the outer casing string to the inner tubing 19. As an alternative to the connection mechanisms used in the couplers 40, 50 as described above, other suitable connection mechanisms include other frictional interference fit mechanisms (e.g., elastomeric seals, and snap rings), weld connections, crimp connections, connections whereby one part bears against another (e.g., by use of shoulders formed on the parts), and packers that are actuated by mechanical and/or hydraulic means, or by swelling upon contact with wellbore fluids. It will be understood that one or a combination of such connection mechanisms may be used to couple the outer casing section 12 to adjacent portions of the casing string, and to couple the outer casing section 12 to the steam dispersion device. Use and operation

In use and operation of the exemplary embodiment of the apparatus 10 shown in the Figures, the steam injection assembly (or steam dispersion device) is assembled and connected to the outer casing section 12 before being run into a wellbore. For example, moveable member 20 is inserted inside the intermediate portion 16. Intermediate portion 16 is coupled with uphole portion 13, and downhole portion 14, thus forming the assembled steam dispersion device. The assembled steam dispersion device is then inserted into the outer casing section 12. Expansion coupler 50 is installed at the uphole end 6 of the apparatus 10 by threading outer connection 52 onto the corresponding threads of outer casing section 12, and by inserting the uphole portion 13 into inner connection 54 so that its outer surface engages with the sealing elements 56. Dual coupler 40 is then installed at the downhole end 8 of the apparatus 10 by threading outer connection 42 onto the corresponding threads of outer casing section 12, and inner connection 44 onto the corresponding threads of downhole portion 14.

The apparatus 10 (or a plurality of apparatus' 10) as a whole can then be connected inline with adjacent sections of the casing string using the downhole casing connection 46 and the uphole casing connection 58 to form part of the casing string, such as shown in Figure 7. Steam can be provided from the surface, for example by a pump or injector, through the casing string and into inner tubing bore 18 of the apparatus 10. A shifting tool (not shown), such as a sleeve shifting tool when the moveable member is a sleeve, can be run downhole in the bore of the casing string, for example using a wireline, until it reaches inner tubing bore 18 of the apparatus 10. The shifting tool can then be used to exert sufficient axial force on the moveable member, for example, sleeve 20, to slide the sleeve 20 from the closed position into the open position, thereby permitting fluid communication between inner tubing bore 18 and annulus 15. Steam can then flow from the inner tubing bore 18 into annulus 15, and from annulus 15 into the hydrocarbon formation through the radial openings of outer casing section 12. When it is desired to cease the release of steam from inner tubing bore 18 into the formation, the shifting tool can be used to actuate the moveable member, for example, sleeve 20, back into the closed position.

In a further embodiment, a plurality of apparatus' 10 may be assembled and connected inline with a plurality of adjacent sections of the casing string as described above using downhole casing connections 46 and uphole casing connections 58 to form part of the casing string. Steam can be transferred from the surface, for example by a pump or injector, through the casing string and into inner tubing bore 18 of a first apparatus 10. A shifting tool can be run downhole in the bore of the casing string, for example using a wireline, until it reaches inner tubing bore 18 of the first apparatus 10. The shifting tool can then be used to exert sufficient axial force on the moveable member to slide the moveable member from the closed position into the open position, thereby permitting fluid communication between inner tubing bore 18 and annulus 15. Steam can then flow from the inner tubing bore 18 into annulus 15, and from annulus 15 into the hydrocarbon formation through the radial openings of outer casing section 12. When it is desired to cease the release of steam from inner tubing bore 18 into the formation, the shifting tool can be used to actuate the moveable member 20 back into the closed position. The shifting tool can then be moved to inner tubing bore 18 of at least a second apparatus 10 and the steps above may be repeated.

The apparatus 10 of the present disclosure obviates the need for a separate steam tubular to be run downhole after the casing string is in position. This may result in substantial time and cost savings in completing a steam injection well. Additionally, in exemplary embodiments, the inner tubing bore 18 (being similar in diameter to the casing section bore 1 1 ) is relatively open when compared with a wellbore casing incorporating a steam tubular as conventionally used in a SAGD operation. This may allow for greater production through the casing string. Further still, the steam dispersion device is run downhole with the outer casing section 12 only after being installed and anchored in the outer casing section 12 by means of the couplers 40, 50. This may reduce the risk of damage to the steam dispersion device as compared with the risk of damage to conventional steam injection tools located on steam tubulars that are run into casings installed in the wellbore. Although exemplary embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the disclosure. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the invention is defined and limited only by the claims that follow.

Claims

An apparatus operable to be installed in-line with an adjacent downhole portion of a casing string to form a part of the casing string, the apparatus comprising:

(a) an outer casing section comprising an outer section bore, said outer casing section operable to line a portion of a wellbore and be coupled in-line with said adjacent downhole portion of said casing string when said casing string is deployed in said wellbore;

(b) a steam dispersion device located within the outer section bore of the outer casing section, said steam dispersion device operable to disperse steam through said outer casing section into said wellbore when said casing string is deployed in said wellbore and said outer casing section is coupled in-line with said adjacent downhole portion of said casing string;

(c) at least one coupling mechanism operable to couple the apparatus in-line with the adjacent downhole section of the casing string.

An apparatus as claimed in claim 1 wherein said steam dispersion device is coupled by at least one coupling mechanism to said outer casing section.

An apparatus as claimed in claim 1 wherein said steam dispersion device is sealingly coupled to said outer casing section, such that when said casing string is in said wellbore and said outer casing section is coupled in-line with said adjacent downhole portion of said casing string, said steam dispersion device is in communication with steam supplied from said adjacent downhole portion of said casing string.

The apparatus of claim 1 wherein:

- said steam dispersion device comprises an inner tubing with an inner tubing bore in communication with steam supplied from said adjacent downhole portion of said casing string and having at least one opening operable to communicate steam to said outer casing section for dispersion into said wellbore; and wherein said at least one coupling mechanism comprises a coupler that is operable to provide:

(i) an outer connection operable for sealing connection with said outer casing section;

(ii) an inner connection operable for sealing connection with said inner tubing; and

(iii) a third connection operable for connecting to said adjacent downhole portion of said casing string;

and wherein said coupler provides a coupler bore for communication of steam supplied from said adjacent downhole portion of said casing string to the inner tubing bore.

An apparatus operable to be installed in-line with adjacent uphole and downhole sections of a casing string to form a part of the casing string, the apparatus comprising: (a) an outer casing section comprising an outer section bore;

(b) a steam dispersion device located within the outer section bore comprising an inner tubing defining an annulus between the inner tubing and outer casing section, the inner tubing comprising an inner tubing bore and a plurality of inner tubing radial openings arranged along a length of the inner tubing; and

(c) a first coupler and a second coupler for coupling the apparatus in-line with the adjacent up-hole and downhole sections of the casing string, wherein the first coupler is located at a downhole end of the apparatus and the second coupler is located at an up-hole end of the apparatus.

The apparatus of any one of claims 1 to 5, wherein the outer casing section further comprises at least one outer casing section radial opening.

The apparatus of any one of claims 1 to 6, wherein the outer casing section further comprises a permeable material disposed about an exterior area of the outer casing section.

The apparatus of any one of claims 5 to 7, wherein the inner tubing comprises an inner tubing up-hole portion, an intermediate portion, and a downhole portion.

The apparatus of claim 8, wherein the plurality of inner tubing radial openings are arranged in multiple rows along the length of and circumferentially around the intermediate portion.

10. The apparatus of any one of claims 5 to 9, wherein the steam dispersion device further comprises a moveable member wherein the moveable member is movable relative to the plurality of inner tubing radial openings.

1 1 . The apparatus of any one of claims 5 to 10, wherein the moveable member is a sliding sleeve.

12. The apparatus of any one of claims 10 to 1 1 , wherein the apparatus further comprises a latching mechanism to secure the moveable member in a plurality of positions.

13. The apparatus of any one of claims 5 to 12, wherein the first coupler is a dual coupler comprising an outer connection for sealing connection with the outer casing section, an inner connection for sealing connection with a downhole portion of the inner tubing, and a downhole casing connection for sealing connection with the downhole section of the casing string.

14. The apparatus of any one of claims 5 to 13, wherein the second coupler is an expansion coupler comprising an outer connection for sealing connection with the outer casing section, an inner connection for sealing connection with an up-hole portion of the inner tubing, and an up-hole casing connection for sealing connection with the up-hole section of the casing string.

15. An apparatus for injecting steam from a casing string bore of a casing string into a wellbore, the apparatus comprising: (a) an outer casing section for lining a portion of the wellbore and for coupling in-line with an adjacent portion of the casing string to form part of the casing string, wherein the outer casing section defines an outer casing section bore; and

(b) a steam dispersion device comprising an inner tubing disposed in the outer casing section bore to define an annulus between the inner tubing and the outer casing section, wherein the inner tubing defines an inner tubing bore for steam communication with the casing string bore of the adjacent portion of casing string; wherein the steam dispersion device is sealingly coupled to the outer casing section prior to the apparatus being disposed in the wellbore, such that, when the apparatus is disposed in the wellbore with the outer casing section coupled in-line with the adjacent portion of the casing string and the inner tubing bore in steam communication with the casing string bore of the adjacent portion of the casing string, the apparatus permits steam communication between the casing string bore of the adjacent portion of casing string and the wellbore only via at least one inner tubing radial opening for steam communication between the inner tubing bore and the annulus, and at least one outer casing section radial opening for steam communication between the annulus and the wellbore.

16. The apparatus of claim 15 wherein the steam dispersion device comprises a moveable member movable relative to the at least one inner tubing radial opening to vary an open area of the inner tubing radial opening and thereby control steam communication between the inner tubing bore and the annulus.

17. The apparatus of any one of claims 15 to 16, further comprising a first coupler for coupling the steam dispersing device to the outer casing section.

18. The apparatus of any one of claims 15 to 17, further comprising a second coupler for coupling the outer casing section in-line with the adjacent portion of the casing string.

19. The apparatus of any one of claims 15 to 16, further comprising at least one coupler, each of the at least one coupler comprising:

(i) an outer connection for connecting the coupler to the outer casing section;

(ii) an inner connection for connecting the coupler to the inner tubing; and

(iii) a casing connection for connecting the coupler to the adjacent portion of the casing string; wherein the coupler defines a coupler bore for steam communication from the casing string bore of the adjacent portion of the casing string to the inner tubing bore.

20. The apparatus of any one of claims 15 to 16, further comprising:

- an up-hole dual coupler for coupling the outer casing section in-line with an adjacent up-hole portion of the casing string; and - a downhole dual coupler for coupling the outer casing section in-line with an adjacent downhole portion of the casing string.

21 . The apparatus of any one of claims 15 to 20, wherein the inner tubing comprises a plurality of portions removably attached to each other.

22. The apparatus of any one of claims 15 to 21 , wherein the movable member is a sleeve slideably disposed within the inner tubing bore.

23. The apparatus of any one of claims 15 to 22, wherein the annulus has a radial dimension as measured between an outside diameter of the inner tubing and an inside diameter of the outer casing section of equal or less than about 10 mm.

24. A method for completing a casing string for injecting steam into a wellbore, the method comprising:

(a) coupling the outer casing section of the apparatus of any one of claims 1 -23 in-line with an adjacent portion of the casing string to form a part of the casing string, with the inner tubing bore of the apparatus in steam communication with a casing string bore of the adjacent portion of the casing string; and

(b) running the part of the casing string downhole into the wellbore.

25. The method of claim 24, wherein step (a) is performed a plurality of times.

26. A completed casing string for injecting steam into a wellbore produced according to the method of claims 24 or 25.

27. A method for injecting steam into a wellbore comprising transferring steam through the casing string of claim 26.

28. Use of the apparatus of any one of claims 1 to 23 to inject steam into a wellbore.

29. Use of the apparatus of any one of claims 1 to 23 to recover hydrocarbons from a subterranean formation in a steam assisted gravity drainage operation.