US20110079390A1

US20110079390A1 - Cementing sub for annulus cementing

Info

Publication number: US20110079390A1
Application number: US12/995,138
Authority: US
Inventors: Daniel Jon Themig
Original assignee: Packers Plus Energy Services Inc
Current assignee: Packers Plus Energy Services Inc
Priority date: 2008-05-30
Filing date: 2009-06-01
Publication date: 2011-04-07
Also published as: EP2297427A1; EP2297427A4; WO2009143628A1; AU2009253700A1; CA2726200A1

Abstract

A cementing sub for wellbore annulus cementing that allows certain regions of the wellbore annulus to be cemented while other regions are left open for perforating, activation or controllable ported access. The cementing sub may include a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface; a port through the wall of the tubular body providing communication between the inner bore and the outer surface, the port including an openable closure; a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface and being isolated from communication with the inner bore; a first annular packer encircling the tubular body and positioned between the port and the inlet; and a second annular packer encircling the tubular body and positioned between the port and the outlet.

Description

FIELD

The present invention relates to downhole tubulars and, in particular, a wellbore tubular device for assisting annulus cementing operations.

BACKGROUND

Wellbores are often completed by introduction of cement around the tubular in the annulus between the tubular and the borehole wall. The cement holds the tubular in place in the well and creates isolation by controlling against fluid passage through the wellbore annulus from one section of the well to another. Isolation serves the purpose of preventing flow of fluids or gas from one section of a well that may be undesirable such as water, to a section of the well that would otherwise produce hydrocarbon.
In addition, certain operations require that fluid be placed into the well at specific locations. These operations may include acidizing or hydraulic fracturing. The cement in these cases provides isolation by containing the fluid placement to the desired locations in the well to produce desired results. If ports are placed along a tubular string in the well, either cement or packers can be used to isolate one section of the well about one or more ports from one another section. If the ports are cemented in place, the cement circulated into the annulus section of the well may cause problems operating the ports. In addition, the ability to inject fluid into the formation through the ports may prove difficult because the cement will prevent contact and communication with the formation rock. If fracturing is planned, the cement may cause high fracture initiation pressures.
When a ported tubular is positioned in a well, cement generally cannot be used in the usual way since the cement will block the outside of the port such that although the port is opened, fluid treatments are blocked from entering the wellbore because of the presence of the cement. If fluid is introduced at a pressure that would normally fracture the well, the force of the fluid injection is distributed over a wider area by the cement such that the force is dissipated and the treatment may be rendered less than effective.

SUMMARY

The invention relates to a wellbore tubular for assisting annulus cementing operations by allowing some sections of the well to be left uncemented and to provide the option to either perforate or to activate or open and close ports within these uncemented areas.
If ports are used and the annulus surrounding the ports is not cemented, but the adjoining areas on each side of the ports contain a cemented annulus, then the ports, when opened, will provide direct contact with the formation for production or fluid placement (formation stimulation), and the benefits of cement to perform zonal isolation.
This invention provides a wellbore tubular, a method and a wellbore tubular installation to allow cementing of the annulus while leaving the area surrounding the ports uncemented.
In accordance with a broad aspect of the present invention, there is provided method for installing a tubular string in a wellbore, the method comprising: providing a tubular string including an inner bore and an outer surface, an upper annular packer encircling the tubular string, a lower annular packer encircling the tubular string below the upper annular packer and a conduit extending to provide a fluid tight path from a conduit first open end below the lower packer in communication with the outer surface and a conduit second open end above the upper packer in communication with the outer surface; running the tubular string into the wellbore to create an annulus between the tubular string and the wellbore wall; setting the packers to isolate an intermediate portion of the annulus from annular regions above the upper packer and below the lower packer; pumping cement into the annular regions and through the conduit, such that the conduit and the annular regions above the upper packer and below the lower packer become filled with cement while the intermediate portion of the annulus is isolated from introduction of cement thereto; and allowing the cement to set.
In accordance with another broad aspect of the present invention, there is provided a wellbore tubular comprising: a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface; a port through the wall of the tubular body providing communication between the inner bore and the outer surface, the port including an openable closure; a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface and being isolated from communication with the inner bore; a first annular packer encircling the tubular body and positioned between the port and the inlet; and a second annular packer encircling the tubular body and positioned between the port and the outlet.
In accordance with another broad aspect of the present invention, there is provided a tubular installation in place in a borehole comprising: a tubing string in a borehole creating an annular space between the tubing string and a wall of the borehole, the tubing string including a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface; a port through the wall of the tubular body, which when open provides communication between the inner bore and the outer surface; a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface but being isolated from communication with the inner bore; a first annular packer encircling the tubular body and expanded to seal against communication between the port and the inlet; and a second annular packer encircling the tubular body and expanded to seal against communication between the port and the outlet, the first packer and the second packer dividing the annular space into an upper annular space above the second packer, a middle annular space between the first packer and the second packer and a lower annular space below the first packer.
It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawings, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:

FIG. 1 is a schematic sectional view along a portion of a well bore with a tubular therein, according to one aspect of the invention.

FIG. 2 is a sectional view along a portion of a well bore with a tubular string therein.

FIG. 3 is a perspective view of a wellbore tubular according to the present invention.

FIG. 4 is a sectional view along the long axis of another wellbore tubular according to the present invention.

DESCRIPTION OF VARIOUS EMBODIMENTS

The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
With reference to the FIG. 1, a wellbore tubular and an installation are shown according to various aspects of the present invention.
A wellbore tubular may include tubular body 10 including a first end, an opposite end and a wall defined between an inner bore 10 a extending from the first end to the opposite end and an outer surface 10 b; one or more ports 18 through the wall of the tubular body providing communication between the inner bore and the outer surface, each port including an openable closure 20; a conduit 24 along the wall of the tubular extending between openings from the area around the outer surface to the conduit. For ease of reference, the openings can be considered to include an inlet 26 adjacent the first end and an outlet 28 adjacent the opposite end. The inlet and the outlet open to the outer surface but are isolated from communication with inner bore 10 a of the tubular. In this way fluids can pass through the conduit from the inlet to the outlet (or vice versa) along the wall of the tubular without flowing from the conduit out through the ports toward the outer surface of the tubular body and without flowing from the conduit into the inner diameter of the tubular. As will be appreciated, the port and the conduit are out of fluid communication. For example, the conduit may extend along the wall and the port may pass through the wall without the port and conduit opening into each other.
The wellbore tubular further may include a first annular packer 30 encircling the tubular body and positioned between port 18 and the inlet 26 and a second annular packer 36 encircling the tubular body and positioned between the port and outlet 28.
The ports and their openable closures may take various forms. For example, the openable closures may include burst discs, dissolvable materials, a shearable cap, a sliding sleeve valve (as shown), etc.
The conduit may take various forms. For example, the conduit may include one or more discreet tubulars attached on or embedded in the tubular body wall, the tubular body wall may be formed of thick materials and the conduit may bored axially therethrough, the tubular body wall may include a hollow annular space that defines the conduit, etc. Likewise, the inlets and outlets may take various forms such as discreet openings from the outer surface into the conduit. Alternately, the inlets and outlets may be defined by larger open areas such as the full annular opening between inner and outer tubular shells forming a hollow wall of the tubular body.
The annular packers may also take various forms. The packers may be expandable, inflatable, etc. In one embodiment, the packers are solid body-type packers such as including one or more extrudable elements. The extrudable elements may be driven to expand by hydraulic swelling or compression drivers. For example, one useful packer type may be a hydraulically driven compression set packer such as one available from the assignee of this application, under the trade name Rockseal™.
The wellbore tubular may be used to form a tubular installation for placement in a wellbore. In such an installation an annular space 40 may be formed between the wellbore tubular and a wall 50 of the borehole. Using a wellbore tubular such as that described above as an example, the tubular installation may include the wellbore tubular placed in the wellbore with the first annular packer and the second annular packer expanded. In such an installation, the first packer and the second packer divide the annular space into an upper annular space above the second packer, an intermediate annular space 40 a between the first packer and the second packer and a lower annular space below the first packer. When set against a wellbore wall (cased or open hole), the first annular packer seals against communication between the port and the inlet through the annular space and the second annular packer seals against fluid communication along the annular space between the port and the outlet.
Such an installation may be employed to affect a method for installing a tubular string in a wellbore. According to one embodiment, the method may include first providing a tubular including a port extending from an inner bore of the tubular to open on the outer surface, an upper annular packer encircling the tubular above the port, a lower annular packer encircling the tubular below the port and a conduit extending to provide a fluid path from a conduit first open end below the lower packer and a conduit second open end above the upper packer. Such a tubular can run into the wellbore, thereby creating an annulus between the tubular and a wall of the wellbore. Of course, the tubular will likely be installed in a string of tubulars and is run in by running in the string, by methods well known in the art. In such an embodiment, the inner bore of the tubular may be in communication with the surface through an upper string extending above the tubular. Once in position in the wellbore, the packers may be set to isolate an intermediate portion of the annulus from regions of the annulus above the upper packer and below the lower packer. Thereafter, cement may be pumped (arrows C) into through the annular regions and through the conduit.
The conduit allows the cement to pass from the regions below the lower packer to the regions above the upper packer without cementing the intermediate annular region. Closures on the ports prevent the cement from passing into the intermediate annular region through the port. As such the tubular can be annularly cemented into the wellbore while leaving the annular area about the port of the tubular open. As such fluids can pass from the inner bore of the tubular out into contact with the wellbore (and vice versa) without hindrance by cement in the annular region about the port.
It will be appreciated that cement is usually pumped through the tubular inner bore from surface to an end of the tubular. Pumping is continued such that the cement then moves up through the annular space about the tubular back toward surface. However, it is to be understood that the method encompasses, and the wellbore tubular is useful for, a procedure where cement is pumped down towards the upper packer and passes through the conduit to exit below the lower packer.
After the cement is pumped through the annular space, the cement is allowed to set as by holding the cement in the annular space by holding pressure above the cement or by use of a cement float. Thereafter, the ports may be opened by, for example, opening or removing the closures. Wellbore operations can then begin, for example, production or wellbore treatments though the port such as for example by injection of fracturing fluid, stimulation fluids, etc.
With reference to FIG. 2, a wellbore installation could include a string 60 incorporating one or, as shown, more of the wellbore tubulars according to the invention such as, for example, as shown in any one of FIG. 1, 3 or 4 or others not specifically illustrated. While two tubulars are shown, the string could include many such tubulars and possibly other components. The tubulars include a port 18 extending from an inner bore 10 a of the tubular to open on the outer surface 10 b, an upper annular packer 36 encircling the tubular above the port, a lower annular packer 30 encircling the tubular below the port and a conduit 24 extending to provide fluid communication between the outer surface below the lower packer and the outer surface above the upper packer without opening into the outer surface between the packers. The inner bores 10 a of the tubulars are open to the inner diameter 60 a of the string 60.
Such a string 60 can run into a wellbore 50, thereby creating an annulus 40 between the string and the wall of the wellbore. Of course, the tubular will likely be installed in a string of tubulars and is run in by running in the string, by methods well known in the art. Once in position in the wellbore, the packers may be expanded or allowed to expand to isolate an intermediate portion 40 a of the annulus from regions of the annulus above the upper packers and below the lower packers. Thereafter, cement may be pumped through the annular regions and through the conduits. In the illustration of FIG. 2, the cement can be seen, as shown by stippling, in the annular region 40 about the string but not in the intermediate portions 40 a between the packers of the tubulars. In this way, the intermediate portions 40 a remain open such that when ports 18 are opened, fluids can pass through inner bore 60 a of the string, which is continuous with inner bores 10 a of the tubulars, and out through the ports into contact with the wellbore without hindrance by cement in the annular region about the port. Fluids, for example, may effect a fracing operation such as that shown wherein fractures 62 are generated in the formation about the wellbore.
The ports may be opened by various means such as by tubing manipulation, bursting, shearing, etc. For example, the ports may be opened by shearing as disclosed in applicant's corresponding U.S. Pat. No. 6,907,936, issued Jun. 21, 2005 or by a sliding sleeve type valve as more fully disclosed in applicant's U.S. Pat. No. 7,134,505, issued Nov. 14, 2006. Alternately or in addition, the ports may be opened all at once, as by use of a hydraulically openable valve as disclosed in applicants corresponding PCT application PCT/CA2009/000599, filed Apr. 29, 2009. Alternately, the ports may be opened in stages, as more fully disclosed in applicant's U.S. Pat. No. 7,134,505, issued Nov. 14, 2006.
With reference to FIG. 3, another wellbore tubular is shown according to various aspects of the present invention. This wellbore tubular is shown sectioned through its tubular body 110 just below its ports 118. Ends 110 c and the other of which cannot be seen in this view, include forms, such as threading as shown for connection into a tubular string. As will be appreciated, such a tubular is often called a sub. Ports 118 extend laterally out through the wall of the tubular body providing communication between the tubulars inner bore and its outer surface. A sliding sleeve valve 120, shown partially open in this view, acts as an openable closure for the ports.
A plurality of conduits 124 are formed along the wall of the tubular by attaching axial tubular segments to the outer surface of the tubular. The conduits extend from upper and lower open ends 128, only one of which can be seen in this view. First and second annular packers 132, only one of which can be seen in this view, are installed about the tubular. The conduits pass through the packers and along the tubular wall to provide a fluid passage along the wall of the tubular without opening to the outer surface of the tubular between the packers and or into the inner bore of the tubular.
With reference to FIG. 4, yet another wellbore tubular is shown according to various aspects of the present invention. This wellbore tubular is shown sectioned along its long axis through a port 218. Ends 210 c, while shown as blanks, can be formed to allow connection of the tubular body 210 into a tubular string. As will be appreciated, such a tubular is often called a sub. Port 218 extends laterally out through the wall of the tubular body providing communication between the tubular body inner bore 210 a and its outer surface 210 b. A sliding sleeve valve 220, in this view shown closed but in the process of being opened, acts as an openable closure for the port 218.
In this illustrated embodiment, the sliding sleeve is moveable remotely from its closed port position, substantially as shown, to its position permitting through-port fluid flow, for example, without having to run in a line or string for manipulation thereof. In one embodiment, the sliding sleeve is actuated by a device, such as a ball 221 (as shown) or plug, which can be conveyed by gravity or fluid flow through the tubing string. The device, in this case ball 221, engages against the sleeve and, when pressure is applied through the inner bore 210 a, as from surface through a string to the tool, ball 221 seats against and creates a pressure differential above and below the sleeve which drives the sleeve toward the lower pressure side.
In the illustrated embodiment, the inner surface of the sleeve which is open to the inner bore 210 a of the sub defines a seat 223 onto which a suitably sized ball, when launched from surface, can land and seal thereagainst. When the ball seals against the sleeve seat and pressure is applied or increased from surface, a pressure differential is set up which causes the sliding sleeve on which the ball has landed to slide to a port-open position. When the port 218 is opened, fluid can flow therethrough to the annulus between the tubing string and the wellbore and thereafter into contact with formation.
A conduit 224 is formed along the wall of the tubular body by attaching an axial tubular segment to the outer surface of the tubular. The axial tubular segment can, for example, be obtained from a pipe having a radius smaller than the radius of the wellbore tubular and a section of the wall of the tubular can be cut along the tubular's length substantially parallel to the long axis of the tubular. Alternately, the axial tubular segment can be obtained by bending a sheet of material along its length. In any event, the axial tubular segment is attached with its concave side facing against the outer surface of the wellbore tubular, as by welding, etc. The conduit extends between open ends 228, only one of which can be seen in this view. First and second annular packers 232 are installed about the tubular body. The conduits pass through the packers, when they are expanded, and along the tubular wall to provide a fluid passage along the wall of the tubular without opening to the outer surface of the tubular between the packers and or into the inner bore of the tubular.
Although other types of packers may be employed, in the illustrated embodiment, packers 232 are shown as the type set by hydraulic compression. Such a packer includes an extrudable packing element 266 carried in an unset condition which is driven to extrude by a hydraulically actuated setting mechanism 268. These parts are mounted on the tubular body and radially outwardly of the conduit. Element 266 is formed of an elastomer, such as for example, rubber and may include an enlarged cross section to provide excellent expansion ratios to set in oversized holes.
Packing element 266 may be, for example, mounted between a fixed stop ring 268 a and compressing ring 268 b. The hydraulically actuated setting mechanism may include a port 268 c through the tubular body which provides fluid access to a hydraulic chamber 268 d defined behind compressing ring 268 b. Compressing ring 268 b includes a piston face 268 e against which the hydraulic pressure in chamber 268 d acts to drive the ring against the packing element to compress and, therefore, expand it outwardly.
Thus, the packers illustrated in FIG. 4 are set by pressuring up the tubing string such that fluid enters the hydraulic chamber and acts to drive compression of the packing elements, thereby extruding them outwardly. A lock may be provided to act against retraction of the packing elements out of the extruded position.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or “step for”.

Claims

1. A method for installing a tubular string in a wellbore, the method comprising:

providing a tubular string including an inner bore and an outer surface, an upper annular packer encircling the tubular string, a lower annular packer encircling the tubular string below the upper annular packer and a conduit extending to provide a fluid tight path from a conduit first open end below the lower packer in communication with the outer surface and a conduit second open end above the upper packer in communication with the outer surface; running the tubular string into the wellbore to create an annulus between the tubular string and the wellbore wall; setting the packers to isolate an intermediate portion of the annulus from annular regions above the upper packer and below the lower packer; pumping cement into the annular regions and through the conduit, such that the conduit and the annular regions above the upper packer and below the lower packer become filled with cement while the intermediate portion of the annulus is isolated from introduction of cement thereto; and allowing the cement to set.

2. The method of claim 1 wherein the tubular string includes a port through its wall providing communication between the inner bore and the outer surface, the port positioned in the intermediate portion, and the method further comprises: opening the port after allowing the cement to set.

3. The method of claim 1 further comprising: introducing wellbore treatment fluids to the intermediate portion from the tubular string.

4. The method of claim 1 further comprising: allowing produced fluids to pass through the intermediate portion and into the tubular string.

5. The method of claim 1 wherein the tubular string includes a second set of packers below the lower packer and a second conduit providing a fluid communication channel from the outer surface below a lower-most packer of the second set of packers to the outer surface above an upper-most packer of the second set of packers, the method includes setting the second set of packers to isolate a second intermediate portion of the annulus from annular regions above the upper-most packer and below the lower-most packer; pumping cement into the annulus to fill the annular region below the lower-most packer, the second conduit, the annular region between the upper-most packer of the second set of packers and the lower packer, the conduit and the annular region above the upper packer, while the intermediate portion and the second intermediate portion of the annulus remain isolated from introduction of cement thereto.

6. A wellbore tubular comprising: a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface; a port through the wall of the tubular body providing communication between the inner bore and the outer surface, the port including an openable closure; a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface and being isolated from communication with the inner bore; a first annular packer encircling the tubular body and positioned between the port and the inlet; and a second annular packer encircling the tubular body and positioned between the port and the outlet.

7. The wellbore tubular of claim 6, wherein the conduit is formed of at least an axial segment of a tubular carried on the tubular body wall.

8. The wellbore tubular of claim 6, wherein the conduit is formed of a tubular carried on the tubular body wall.

9. The wellbore tubular of claim 6, wherein the conduit is formed of a hollow annular space along the tubular body wall.

10. The wellbore tubular of claim 6, wherein the openable closure includes a sliding sleeve valve.

11. The wellbore tubular of claim 6, wherein the first annular packer and the second annular packer are hydraulically settable.

12. A tubular installation in place in a borehole comprising: a tubing string in a borehole creating an annular space between the tubing string and a wall of the borehole, the tubing string including a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface; a port through the wall of the tubular body, which when open provides communication between the inner bore and the outer surface; a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface but being isolated from communication with the inner bore; a first annular packer encircling the tubular body and expanded to seal against communication between the port and the inlet; and a second annular packer encircling the tubular body and expanded to seal against communication between the port and the outlet, the first packer and the second packer dividing the annular space into an upper annular space above the second packer, a middle annular space between the first packer and the second packer and a lower annular space below the first packer.

13. The tubular installation of claim 12, wherein the conduit is formed of at least an axial segment of a tubular carried on the tubular body wall.

14. The tubular installation of claim 12, wherein the conduit is formed of a tubular carried on the tubular body wall.

15. The tubular installation of claim 12, wherein the conduit is formed of a hollow annular space along the tubular body wall.

16. The tubular installation of claim 12, wherein the openable closure includes a sliding sleeve valve.

17. The tubular installation of claim 12, wherein the first packer and the second packer are hydraulically settable.

18. The tubular installation of claim 12 further comprising a second set of packers below the lower packer, the second set of packers expanded to seal the annulus between the tubing string and the wall, creating a second middle annular space and a second conduit providing a fluid communication channel from the annulus below a lower-most packer of the second set of packers to the annulus above an upper-most packer of the second set of packers without opening into the middle annular space.