Casing shoe valve

Abstract

A casing shoe valve includes a valve body having an internal bore and a connection on each longitudinal end to enable connection of the valve body within a tubular string. A first valve element is fixedly disposed at a first axial location within the internal bore. A second valve element is disposed in the internal bore at a spaced apart axial location from the first valve element, the second valve element being held at the spaced apart axial location by a dissolvable retaining element. A biasing element is arranged to urge the second valve element toward the first valve element. The first and second valve elements are arranged to close the internal bore to fluid flow when they are engaged with each other.

Description

PATENT APPLICATION ATTORNEY DOCKET NO. FTL-24-08PCTCASING SHOE VALVE CROSS REFERENCE TO RELATED APPLICATIONS

[0001] Not Applicable.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not ApplicableNAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

[0003] Not Applicable.BACKGROUND

[0004] This disclosure relates to the field of valves used at the bottom of a “string” of conduit such as casing or liner inserted into a well drilled through subsurface earthen formation.

[0005] Wells drilled through subsurface earthen formations are typically “completed” by inserting in place a tubular string such as casing or liner. Some such strings of casing or liner may comprise perforated pipe segments or screens at selected axial locations along the string to enable flow into the tubular string of hydrocarbons from the surrounding earthen formations. Casing shoe valves are used to create a barrier to flow of fluid from below the bottom of the tubular string after it has been inserted into the drilled borehole. Casing shoe valves known in the art are designed to be open to fluid flow to facilitate movement of the tubular string into the borehole and then close after the tubular string is fully inserted. Such casing shoe valves typically include a timing device that automatically causes the valve to close after a predetermined period of time. Such valves are quite expensive to produce.PATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCT

[0006] There continues to be a need for improved, less expensive to produce casing shoe valves.SUMMARY

[0007] One aspect of the present disclosure relates to a casing shoe valve. A casing shoe valve according to this aspect includes a valve body having an internal bore and a connection on each longitudinal end to enable connection of the valve body within a tubular string. A first valve element is fixedly disposed at a first axial location within the internal bore. A second valve element is disposed in the internal bore at a spaced apart axial location from the first valve element, the second valve element being held at the spaced apart axial location by a dissolvable retaining element. A biasing element is arranged to urge the second valve element toward the first valve element. The first and second valve elements are arranged to close the internal bore to fluid flow when they are engaged with each other.

[0008] In some implementations, the biasing element comprises a coil spring.

[0009] In some implementations, the second valve element comprises a sleeve.

[0010] In some implementations, the first valve element comprises a plug having a small diameter segment arranged to fit within an internal bore of the sleeve and a large diameter segment arranged to sealingly fit within the internal bore of the valve body.

[0011] In some implementations, the large diameter segment comprises at least one flow port.

[0012] In some implementations, the first valve element comprises a sleeve.

[0013] In some implementations, the second valve element comprises a plug having a small diameter segment arranged to fit within an internal bore of the sleeve and a large diameter segment arranged to sealingly fit within the internal bore of the valve body.

[0014] In some implementations, the large diameter segment comprises at least one flow port.

[0015] In some implementations, the dissolvable retaining element comprises a pin.PATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCT

[0016] Other aspects and possible advantages will be apparent from the description and claims that follow.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 shows an axial cross sectional view of an example implementation of a casing shoe valve according to the present disclosure.

[0018] FIG. 1A shows a cross sectional view of a valve closure element of the example valve shown in FIG. 1

[0019] FIG. 2 shows an oblique cut away view of the example valve shown in FIG. 1.

[0020] FIG. 3 shows a cross sectional view of the example valve of FIG. 1 after a valve sleeve has moved into engagement with a valve closure element.DETAILED DESCRIPTION

[0021] Expressed generally, a casing shoe valve according to the present disclosure comprises a first valve element fixedly disposed within a valve housing and a second valve element disposed in the valve housing spaced apart from the first valve element and retained in axial position by a dissolvable retaining device. The second valve element is urged toward the first valve element by a biasing element, wherein dissolution of the dissolvable retaining device enables the second valve element to move to engage the first valve element. Engagement of the first valve element with the second valve element closes the casing shoe valve to flow in both directions. The second valve element may comprise a locking device to retain the second valve element into engagement with the first valve element once engagement takes place. The first valve element and the second valve element comprise flow features that enable fluid movement therethrough when the first and second valve elements are axially separated, and stop fluid movement when the first and second valve elements are engaged with each other. Example implementations will be explained below

[0022] FIG. 1 shows an axial cross sectional view of an example implementation of a casing shoe valve (“valve”) 1 according to the present disclosure; and FIG. 2 shows anPATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCToblique cut away view of the same example valve 1, wherein like components are labeled with like reference numerals. The valve 1 may comprise a generally cylindrically shaped housing or valve body 10 having a connection 10A, 10B at each longitudinal end, such as a threaded connection, to enable coupling the valve 1 into a tubular string (not shown) inserted into a subsurface wellbore (not shown). The type of the connection 10A, 10B is not a limitation on the scope of the present disclosure; it is only necessary that the connections 10A, 10B make a pressure tight seal when connected to an adjacent tubular element.

[0023] An internal bore of the valve body 10 may comprise a first shoulder 10D defined by a reduced internal diameter axial section wherein a spring retainer 14 may be inserted into the internal bore from one longitudinal end of the valve body 10 and stopped from movement longitudinally by the first shoulder 10D. The spring retainer 14 may be locked in place during assembly of the valve 1 by a locking element such as a snap ring 12 or similar retaining feature that engages the internal bore of the valve body 10. A biasing element 16 such as a spring, e.g., a coil spring, may at one longitudinal end thereof engage one side of the spring retainer 14. An opposed side of the biasing element 16 may be in contact with one side of a first valve element, which in the present example implementation may be a valve sleeve 26. The valve sleeve has an external diameter enabling longitudinal movement within the internal bore of the valve body 10, such movement limited as will be further explained.

[0024] A threaded port 18 is made through the wall of the valve body 10 at an axial location wherein the valve sleeve 26 is to be held in place prior to operation of the valve 1 , to be explained further below. A retaining device, such as a pin 19 may be disposed in the threaded port 18 such that it engages the exterior surface of the valve sleeve 26, e.g., in one or more openings 26A in the circumference of the valve sleeve 26, and thereby holds the valve sleeve 26 in axial position. The retaining pin 19 may be made from, e.g., chemically soluble material, e.g., aluminum, that can be readily dissolved by introducing liquid, e.g., caustic solution such as sodium hydroxide into the liquid as it is pumped through the valve body 10 (and through the tubular string). Another non-limiting example of material for the retaining pin 19 may be magnesium, to be dissolved in acidic fluid pumped through thePATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCTvalve 1. Upon sufficient solution of the retaining pin 19, the valve sleeve 26 may be free to move longitudinally along the internal bore of the valve body 10. The threaded port 18 may be closed to fluid flow, e.g., by a pipe plug 20 or other sealing device.

[0025] The valve sleeve 26 may comprise on its exterior surface a seal 22 such as an o- ring to exclude fluid movement between the valve sleeve 26 and the internal bore of the valve body 10. The valve sleeve 26 may also comprise on its exterior surface such as in a suitable retaining groove formed therein a retaining ring 24, e.g., a snap ring, C ring or collet that is biased outwardly so as to engage a snap ring groove 28 formed in the internal bore of the valve body 10 at an axial position proximate a second valve element, which in the present example is a valve closure element 13 disposed in the internal bore of the valve body 10. The valve closure element 13 is axially spaced apart from the initial position of the valve sleeve 26 as shown in FIG. 1.

[0026] The order in which the valve closure element 13 and its associated components, and the valve sleeve 26 and its associated components are assembled within the valve body 10 is not important. Assembly may begin at either longitudinal end of the valve body.

[0027] The valve closure element 13 may comprise a large diameter axial segment 13C that fits within the internal bore of the valve body 10 sufficiently closely to enable sealing using, e.g., an o ring (not shown) or similar seal. In some implementations, the valve 13 may be threaded into the valve housing 10. In such examples, there is no need to have an o-ring to seal the valve closure element because once the valve 1 is operated to close, the valve 1 will shut both flow paths thorugh seals 22 and 30 The internal bore of the valve body 10 may comprise a second shoulder 10C to provide a positive stop to further axial movement of the valve closure element 13 within the valve body 10. The valve closure element 13 may be retained in its axial position after being stopped by the second shoulder 10C by a retainer (not shown) such as a snap ring engaged with the internal bore of the valve body 10 as shown in FIG. 1 ; or as explained above the valve closure element may be threaded into the valve housing 10. The valve closure element 13 may comprise within the large diameter axial segment 13C one or more fluid flow ports, shown at 13 A in FIG. 1A, to enable fluid flow through the valve closure element when the components of the casingPATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCTshoe valve 1 are located as shown in FIG. 1, that is, the valve sleeve 26 and the valve closure element 13 are axially spaced apart. The valve closure element 13 may comprise a smaller diameter axial segment or “plug” 13B, which may comprise a seal 30 such as an o ring disposed on its exterior surface, that engages the interior surface of the valve sleeve 26 when the valve sleeve 26 moves toward and engages the valve closure element 13. Upon such engagement, the plug 13B sealing fills the internal diameter of the valve sleeve 26, whereby fluid flow through the casing shoe valve 1 is stopped in both directions.

[0028] In assembling the casing shoe valve 1, the valve closure element 13 may be inserted into the internal bore of the valve body 10 from the longitudinal end having connector 1 OB and moved until the valve closure element 13 contacts the second shoulder 10C. The retainer 34 may then be inserted into the internal bore of the valve body 10 so as to lock the valve closure element 13 in place. In some examples, as explained above, the valve closure element 13 may be threaded into the valve housing 10 and no retainer as shown at 34 is needed.

[0029] The valve sleeve 26 may be inserted into the internal bore in the valve body 10 until one of the openings 26A is disposed at the location of the port 18. The retaining pin 19 may then be inserted into the port 18 and through to the relevant opening 26A to retain the valve sleeve 26 in its initial axial position as shown in FIG. 1. The biasing device (e.g., coil spring) 16 may then be inserted into the internal bore so that it at one end contacts the valve sleeve 26. The spring retainer 14 and following snap ring 12 may then be inserted into the internal bore. A free length of the biasing device 14 may be chosen such that when installed as explained above within the valve body 10, the biasing device 16 exerts sufficient axial force to move the valve sleeve 26 to engage the valve closure element 13.

[0030] The assembled casing shoe valve 1 as shown in FIG. 1 and FIG. 2 is open to fluid flow in either direction. The casing shoe valve 1 may then be assembled into a tubular string (not shown) at a suitable axial location, e.g., near the casing shoe, and the tubular string be inserted into a subterranean wellbore (not shown). A fluid having chemical properties enabling dissolution of the retaining pin 19 may then be moved through the tubular string and the valve 1. When the retaining pin 19 is sufficiently dissolved to enablePATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCTmovement of the valve sleeve 26, the biasing device (coil spring) 16 will urge the valve sleeve 26 toward the valve closure element 13.

[0031] Referring to FIG. 3, the casing shoe valve 1 may be observed wherein the valve sleeve 26 has moved longitudinally so that its interior surface engages the exterior surface of the plug 13B, and the retaining ring 24 engages the groove 28 to lock the valve sleeve 26 in place axially. In this way, the valve sleeve 26 is closed to fluid flow in both directions. Operations on the well (not shown) may then proceed as intended.

[0032] The foregoing described example implementation of a casing shoe valve includes a movable valve sleeve (after dissolution of the retaining pin) and a fixed valve closure element. It will be apparent to those skilled in the art that it is equally possible to arrange a casing shoe valve to include a movable valve closure element and a fixed valve sleeve. Further, the direction in which the casing shoe valve is connected within a tubular string does not affect its operation or applicability. So, for example, the valve closure element 13 could be arranged to have its larger diameter portion 13C held in place by the retaining pin 19, and be in contact with the biasing device (spring) 16, wherein dissolution of the retaining pin 19 enables axial movement of the valve closure element 13 so that the plug 13B engages the valve sleeve 26 to close the valve 1 to fluid flow in both directions.

[0033] In light of the principles and example implementations described and illustrated herein, it will be recognized that the example implementations can be modified in arrangement and detail without departing from such principles. The foregoing discussion has focused on specific implementations, but other configurations are also contemplated. In particular, even though expressions such as in “an implementation," or the like are used herein, these phrases are meant to generally reference implementation possibilities, and are not intended to limit the disclosure to particular implementation configurations. As used herein, these terms may reference the same or different implementations that are combinable into other implementations. As a rule, any implementation referenced herein is freely combinable with any one or more of the other implementations referenced herein, and any number of features of different implementations are combinable with one another, unless indicated otherwise. Although only a few examples have been described in detailPATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCTabove, those skilled in the art will readily appreciate that many modifications are possible within the scope of the described examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

PATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCT CLAIMSWhat is claimed is:

1. A casing shoe valve, comprising:a valve body having an internal bore and a connection on each longitudinal end to enable connection of the valve body within a tubular string;a first valve element fixedly disposed at a first axial location within the internal bore; a second valve element disposed in the internal bore at a spaced apart axial location from the first valve element, the second valve element being held at the spaced apart axial location by a dissolvable retaining element;a biasing element arranged to urge the second valve element toward the first valve element;andwherein the first valve element and the second valve element are arranged to close the internal bore to fluid flow when the first valve element engages the second valve element.

2. The valve of claim 1 wherein the biasing element comprises a coil spring.

3. The valve of claim 1 wherein the second valve element comprises a sleeve.

4. The valve of claim 3 wherein the first valve element comprises a plug having a small diameter segment arranged to fit within an internal bore of the sleeve and a large diameter segment arranged to sealingly fit within the internal bore of the valve body.

5. The valve of claim 4 wherein the large diameter segment comprises at least one flow port.

6. The valve of claim 1 wherein the first valve element comprises a sleeve.

7. The valve of claim 6 wherein the second valve element comprises a plug having a small diameter segment arranged to fit within an internal bore of the sleeve and a large diameter segment arranged to sealingly fit within the internal bore of the valve body.

8. The valve of claim 7 wherein the large diameter segment comprises at least one flow port.PATENT APPLICATION ATTY DOCKET NO. FTL-24-08PCT 9. The valve of claim 1 wherein the dissolvable retaining element comprises a pin.

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