Downhole gravel packing apparatus and method

Abstract

A downhole gravel packing apparatus, comprising: a tubular assembly for being arranged within a wellbore to define an annulus between said tubular assembly and a wall of the wellbore; and a control valve provided within the tubular assembly to control flow of a gravel pack carrier fluid between external and internal regions of the tubular assembly, the control valve comprising a fluid reactant arrangement which reacts with a first fluid to reconfigure the control valve from a first configuration in which flow through the control valve is permitted during a gravel packing operation, and a second configuration in which flow through the control valve is restricted.

Claims

1. A downhole gravel packing apparatus, comprising: a tubular assembly for being arranged within a wellbore to define an annulus between said tubular assembly and a wall of the wellbore; and a control valve provided within the tubular assembly to control flow of a gravel pack carrier fluid between external and internal regions of the tubular assembly, the control valve comprising a fluid reactant arrangement which reacts with a first fluid to reconfigure the control valve from a first configuration in which flow through the control valve is permitted during a gravel packing operation, and a second configuration in which flow through the control valve is restricted; wherein the downhole gravel packing apparatus comprises a sand screen and a base pipe; wherein the sand screen circumscribes the base pipe and defines a screen annulus between the sand screen and the base pipe, the screen annulus being arranged such that fluid may enter the screen annulus from the annulus via the sand screen; wherein the control valve is located in the base pipe to permit flow from the screen annulus into the interior of the base pipe.

2. The downhole gravel packing apparatus according to claim 1, further comprising an inflow control device arranged parallel to the control valve.

3. The downhole gravel packing apparatus according to claim 1, wherein the fluid reactant arrangement comprises a dissolvable support arranged to hold the control valve in the first arrangement, said dissolvable support comprising a material which dissolves in the first fluid.

4. The downhole gravel packing apparatus according to claim 1, wherein the control valve comprises a flow control member and an orifice; wherein when the control valve is in the first configuration, the flow control member is in a first position and fluid may flow through the orifice; and when the control valve is in the second configuration, the flow control member is in a second position and restricts flow through the orifice.

5. The downhole gravel packing apparatus according to claim 4, wherein the fluid reactant arrangement is arranged to hold the flow control member in the first position when the control valve is in the first configuration.

6. The downhole gravel packing apparatus according to claim 5, wherein the control valve comprises a chamber arranged such that fluid flowing through the control valve flows through the chamber and out of the orifice, wherein the flow control member is trapped in the chamber and the fluid reactant arrangement comprises a dissolvable support.

7. The downhole gravel packing apparatus according to claim 6, wherein the flow control member is a ball and the dissolvable support is a second ball.

8. The downhole gravel packing apparatus according to claim 5, wherein the control valve comprises a chamber arranged such that fluid flowing through the control valve flows through the chamber and out of the orifice; wherein the fluid reactant arrangement comprises a dissolvable support in the form of a castellated ring located around the orifice; and in the first configuration, the flow control member and dissolvable support are arranged such that fluid can flow through gaps formed by the flow control member and the castellations and out of the orifice.

9. The downhole gravel packing apparatus according to claim 4, wherein the flow control member comprises a fluid port and the flow control member and fluid port are arranged such that fluid can flow through the fluid port in the flow control member and out of the orifice when the flow control member is in the second position.

10. The downhole gravel packing apparatus according to claim 4, wherein the flow control member comprises a tubular sleeve.

11. The downhole gravel packing apparatus according to claim 10, wherein the base pipe arranged concentrically with the tubular sleeve; wherein the orifice is located in the base pipe; the fluid reactant arrangement comprises a snap ring and dissolvable support arranged in an interface between the base pipe and the tubular sleeve to prevent relative movement of the tubular sleeve and the base pipe when the control valve is in the first configuration; and the snap ring is arranged such that, when the dissolvable support dissolves in the first fluid, the snap ring moves such that it is no longer preventing relative movement of the base pipe and tubular sleeve.

12. The downhole gravel packing apparatus according to claim 10, wherein the base pipe arranged concentrically with the tubular sleeve; wherein the orifice is located in the base pipe; the fluid reactant arrangement comprises a snap ring and a swellable ring arranged in an interface between the base pipe and the tubular sleeve to prevent relative movement of the tubular sleeve and the base pipe when the control valve is in the first configuration; and the snap ring is arranged such that, when the swellable ring swells in the first fluid, the snap ring is moved to an arrangement such that it is no longer preventing relative movement of the base pipe and tubular sleeve.

13. The downhole gravel packing apparatus according to claim 1, wherein the fluid reactant arrangement comprises a material which swells in the first fluid.

14. The downhole gravel packing apparatus according to claim 1, wherein the first fluid comprises one of: the gravel pack carrier fluid, water, acid and oil.

15. A method for gravel packing, comprising: providing a downhole gravel packing apparatus comprising a tubular assembly, within a wellbore to define an annulus between said tubular assembly and a wall of the wellbore, wherein the tubular assembly includes a control valve configured in a first configuration, wherein the downhole gravel packing apparatus comprises a sand screen and a base pipe, wherein the sand screen circumscribes the base pipe and defines a screen annulus between the sand screen and the base pipe, the screen annulus being arranged such that fluid may enter the screen annulus from the annulus via the sand screen, wherein the control valve is located in the base pipe to permit flow from the screen annulus into the interior of the base pipe; delivering a slurry of gravel and a carrier fluid into the annulus; permitting the carrier fluid to enter the tubular assembly via the control valve to retain the gravel within the annulus; exposing a fluid reactant arrangement of the control valve to a first fluid to cause the control valve to be reconfigured to a second configuration in which further flow through the control valve is restricted.

16. The method according to claim 15, further comprising permitting fluid to enter the tubular assembly via an inflow control device.

17. The method according to claim 15, wherein the control valve comprises a flow control member and an orifice and when the control valve is being reconfigured from the first configuration to the second configuration, the flow control member moves from a first position to a second position and restricts flow through the orifice.

18. The method according to claim 17, wherein the fluid reactant arrangement comprises a dissolvable support which holds the flow control member in the first position when the control valve is in the first configuration; and when the dissolvable support is exposed to a first fluid, the dissolvable support dissolves and the flow control member moves from a first position to a second position.

19. The method according to claim 18, wherein fluid flow is permitted through a fluid port in the flow control member when the flow control member is in the second position.

20. The method according to claim 17, wherein the flow control member is a tubular sleeve and the orifice is in the base pipe arranged concentrically with the tubular sleeve; the fluid reactant arrangement comprises a snap ring and a dissolvable support and prevents relative movement of the tubular sleeve and the base pipe when the control valve is in a first configuration; wherein when the fluid reactant arrangement is exposed to a first fluid, the dissolvable support dissolves and the snap ring moves out of a blocking position such that it is no longer preventing relative movement of the base pipe and tubular sleeve.

21. The method according to claim 20, further comprising moving the tubular sleeve from a first position to a second position under the action of a biasing member.

22. The method according to claim 17, wherein the flow control member is a tubular sleeve and the orifice is in the base pipe arranged concentrically with the tubular sleeve; the fluid reactant arrangement comprises a snap ring and a swellable ring and prevents relative movement of the tubular sleeve and the base pipe when the control valve is in a first configuration; wherein when the fluid reactant arrangement is exposed to a first fluid, the swellable ring swells and moves the snap ring out of a blocking position such that it is no longer preventing relative movement of the base pipe and tubular sleeve.

23. The method according to claim 22, further comprising moving the tubular sleeve from a first position to a second position under the action of a biasing member.

24. The method according to claim 15, wherein the fluid reactant arrangement comprises a material which swells in the first fluid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Examples of the present disclosure will now be provided with reference to the following figures:

(2) FIG. 1 is a schematic cross section view of a wellbore completion according to the present disclosure;

(3) FIG. 2A is a schematic cross section view of a downhole gravel packing apparatus according to the present disclosure with a control valve in a first configuration;

(4) FIG. 2B is a schematic cross section view of a downhole gravel packing apparatus according to the present disclosure with a control valve in a second configuration;

(5) FIG. 3 is a partial cut-away view of a downhole gravel packing apparatus according to the present disclosure;

(6) FIG. 4 is a schematic cross section view of a control valve according to the present disclosure;

(7) FIG. 5 is a partial cut-away view of a control valve according to the present disclosure;

(8) FIG. 6 is a perspective view of a fluid reactant arrangement according to the present disclosure;

(9) FIG. 7 is a perspective sectional view of a control valve according to the present disclosure;

(10) FIG. 8 is a schematic cross section view of a downhole gravel packing apparatus according to the present disclosure; and

(11) FIG. 9 is an enlarged view of FIG. 8.

DETAILED DESCRIPTION OF THE DRAWINGS

(12) FIG. 1 shows a wellbore completion. A wellbore 16 has been drilled through foundation 14. A downhole gravel packing apparatus 10 comprising a tubular assembly 18 is located in the wellbore 16. The wellbore completion also comprises a zonal isolation packer 12.

(13) FIG. 1 illustrates how the annulus surrounding the un-expanded packer 12 is smaller than that surrounding the downhole gravel packing apparatus 10. Aspects according to the present disclosure provide more control over annular velocities during gravel packing and annulus pressures both before and after gravel packing, to help provide a good quality gravel pack while maintaining effective zonal isolation.

(14) FIG. 2A shows a downhole gravel packing apparatus 10 in a wellbore during gravel packing. The gravel packing apparatus comprises a sand screen 20 connected to ICD housing 22. The tubular assembly 18 of the apparatus 10 comprises a base pipe 24 via which fluid can reach the surface. The sand screen 20 is arranged to circumscribe the base pipe 24 in a traditional manner and thereby defines a screen annulus between the sand screen 20 and the base pipe 24. An ICD 26 and a control valve 28 are located in parallel in the base pipe 24. The control valve 28 is in a first configuration in which fluid may flow through the control valve 28 between internal and external regions of the tubular assembly.

(15) During gravel packing, a slurry of fluid and gravel is pumped into the annulus formed by the tubular assembly 18 and the wellbore. The arrows show the movement of the fluid. The fluid enters the screen annulus formed between the sand screen 20 and the base pipe 24 via the sand screen 20; travels along this annulus; and enters the interior of the base pipe 24 to travel to the surface via the inflow control device (ICD) 26 and the control valve 28.

(16) The control valve 28 provides an additional route (in addition to the ICD) by which the gravel pack carrier fluid can enter the base pipe 24. Accordingly, the pressure build up in the annulus during gravel packing is less than it would be in the absence of the control valve 28.

(17) FIG. 2B shows the downhole gravel packing apparatus of FIG. 2A, after a fluid reactant arrangement (not shown) has reacted with a first fluid, causing the control valve 28 to reconfigure to a second configuration.

(18) The fluid reactant arrangement may react in any of a plurality of ways. For example it may swell, dissolve, distort, or a combination of any of these. This reaction causes the control valve to go from a first configuration to a second configuration.

(19) The first fluid may be any fluid and may be selected in order to provide the desired operation. The first fluid may be oil, water, acid, fluid carrier fluid or any other fluid which could be found or injected into the wellbore in order to react with the fluid reactant arrangement.

(20) In the second configuration, the control valve 28 of FIGS. 2A and 2B is closed and no fluid flow can pass therethrough. As such, the only route into the base pipe 24 and to the surface is through the ICD 26. This configuration may be used during production. The fluid path is shown in arrows. The fluid enters the screen annulus via sand screen 20; travels along the screen annulus and enters the base pipe 24 via the ICD 26.

(21) The pressure in the annulus can now be controlled by means of the ICD 26 (since the control valve 28 does not provide a fluid flow path). Accordingly, the pressure in the annulus can be set to balance wellbore production using known techniques.

(22) As has been demonstrated by the above discussion, the present disclosure allows pressures within the annulus to be managed (i.e. kept low enough to avoid formation fracturing) during gravel packing, but then allows the pressure to be maintained at the desired level (i.e. a chosen level to balance production) during production. This is achieved by providing an additional flow path (through the control valve 28) which can be active during gravel packing, but then is automatically restricted or closed before, or during, production.

(23) FIG. 3 shows a further aspect of the present disclosure. Similarly to the embodiment of FIGS. 2A and 2B, the downhole gravel packing apparatus of FIG. 3 comprises a tubular assembly comprising a base pipe 24 and sand screen 20. The apparatus of FIG. 3 also includes a sand screen end ring 22 and a plurality of control valves 30. The downhole gravel packing apparatus of FIG. 3 may be used in water injection applications. In order to gravel pack with the apparatus of FIG. 3 in the string, the control valves 30 are held in a first configuration to permit flow through the control valve. Each control valve 30 (when open) provides a flow path for fluid to enter the base pipe 24 from the screen annulus.

(24) Having a large number of control valves 30 in the base pipe 24 increases the maximum flow rate into the base pipe 24 and hence minimises the pressure in the annulus during gravel packing.

(25) Each of the control valves 30 in FIG. 3 provides a fluid path into the base pipe 24 when in a first configuration, but is shut off and does not allow fluid flow in either direction when in a second configuration.

(26) The control valves 30 of FIG. 3 comprise an inlet and orifice with a central chamber. A flow control member in the form of a sphere is present in the central chamber and is surrounded by the fluid reactant arrangement which comprises a swellable material. When the fluid reactant arrangement reacts with the first fluid, it expands, filling the area surrounding the flow control member and thus preventing fluid from flowing through the chamber. Since the sphere is held in place by the swellable material, flow is prevented in both directions through the control valve 30.

(27) FIG. 4 is a cross section of a control valve 32 which may be used in an aspect according to the present disclosure, shown in a first configuration.

(28) The control valve 32 of FIG. 4 would normally be installed in a base pipe 24 such that gravel packing carrier fluid enters the control valve from the top, and exits from the bottom of the figure. The control valve 32 of FIG. 4 could be used in place of the control valves 30 in the embodiment of FIG. 3.

(29) The control valve 32 comprises a plurality of inlets 34 which lead to a chamber 36. In other embodiments a single inlet 36 may be provided. A plurality of orifices 38 lead from the chamber to allow fluid to exit the chamber 36 and the control valve 32. The plurality of orifices 38 are outlets from the control valve 32 and are not designed to create a pressure drop. In other embodiments a single orifice might be provided. A flow control member in the form of a ball 40 is entrapped within the chamber 36. A dissolvable support, in the form of a second ball 42, is also entrapped within the chamber 36. In the first configuration, as shown in FIG. 4, the dissolvable support ball 42 is located adjacent the orifices 38 but, due to the size and arrangement of the dissolvable support ball 42, it is unable to block fluid from passing through the orifices. Flow control member ball 40 is located above (i.e. upstream when gravel packing carrier fluid is entering the base pipe from the annulus) dissolvable support ball 42 and, in the embodiment of FIG. 4, has a much larger diameter than the dissolvable support ball 42. Dissolvable support ball 42 supports flow control member ball 40 in a position which does not obstruct the inlets 34 or the orifices 38—wedged between the dissolvable support ball 42 and a concave surface in the chamber 36. As such, fluid can enter the inlets 34 and leave the orifices 38 of the control valve 32.

(30) The dissolvable support ball 42 dissolves when the dissolvable support ball 42 comes into contact with the first fluid. As the support ball 42 dissolves, the control valve 32 reconfigures into the second configuration. In doing so, the flow member ball 40 is moved towards the orifices 38 due to the motion of the surrounding fluid. Flow control member ball 40 then sits in the curved lower surface of chamber 36 and blocks both orifices 38, thereby preventing fluid from flowing through the control valve 32.

(31) Aspects of the present disclosure are not limited to the geometry of the embodiment of FIG. 4. It is to be understood that in other embodiments the support ball 40 and dissolvable ball 42 may have other relative sizes or may be non-spherical in shape.

(32) FIG. 5 illustrates an alternative control valve 44 according to an aspect of this disclosure.

(33) The control valve 44 of FIG. 5 is of the type that can be used in a production configuration with an ICD, located on the inside of the sand screen. The control valve 44 may therefore be arranged to be located in parallel with an ICD, providing access to the production tubing. The control valve 44 of FIG. 5 is suitable for use as the control valve 28 in FIGS. 2A and 2B, or the control valves 30 in FIG. 3.

(34) The control valve 44 in FIG. 5 is shown in the first configuration.

(35) The control valve 44 of FIG. 5 comprises inlets (not shown) around the circumference of the valve 44 which lead to a chamber 50. Inlets allow fluid to pass into the chamber 50 radially through passages illustrated with arrows in FIG. 5. The control valve 44 has a circular orifice 48 at the base of the chamber 50. A flow control member in the form of a cylinder or disc 52 is located within the chamber 50. A biasing member 56 acts on the upper surface of the disc 52, biasing the disc 52 towards the orifice 48.

(36) In between the disc 52 and the orifice 48 is a dissolvable support in the form of a ring 54 with castellations, or protrusions, forming channels in the upper surface thereof. The ring 54 is shown in FIG. 6. When the control valve 44 is in the first configuration, fluid can reach the orifice 48 by travelling through channels formed between the castellated surface of the ring 54 and the lower surface of the disc 52.

(37) When the dissolvable support member (ring 54) has finished reacting to the first fluid, that is, once the ring 54 has dissolved, biasing member 56 moves the disc 52 towards the orifice 48. This is the reconfiguring of the control valve 44 from the first to the second configuration. Once the disc 52 reaches the bottom of the chamber 50, it seals the orifice 48, thus preventing fluid from travelling through the control valve 44. The control valve 44 is then in the second configuration.

(38) FIG. 7 shows a further example of a control valve 60 according to an aspect of the present disclosure. The housing, inlets 62 (now shown), chamber 50, ring 54, biasing member 56 and orifice 48 of the control valve 60 of FIG. 7 are the same as in FIG. 6 and so will not be discussed.

(39) The flow control member of FIG. 7 is substantially a disc 64. The disc 64 comprises a central fluid port 66. The diameter of the central fluid port 66 is less than the diameter of the orifice 48. The fluid port 66 allows fluid to flow through the disc 64.

(40) When the control valve 60 is in the first configuration, fluid port 66 provides an extra fluid pathway through the control valve 60.

(41) When the control valve 60 is in the second configuration (reconfiguration of the control valve is discussed with reference to FIG. 5), fluid can flow through the control valve 60 via fluid port 66. As such, fluid flow through the control valve 60 is restricted when the control valve 60 is reconfigured to the second configuration, rather than prevented. The control valve 60 therefore acts as an ICD when in the second configuration.

(42) It may therefore be possible to use control valves 60 as illustrated in FIG. 7 in a downhole gravel packing apparatus without a separate ICD—as the control valve can provide a large flow path when in the first configuration, and then restrict (but not eliminate) the flow path when in the second configuration.

(43) FIGS. 8 and 9 illustrate a further downhole gravel packing apparatus according to an aspect of the present disclosure. FIG. 9 is an enlarged view of part of FIG. 8.

(44) The downhole gravel packing apparatus of FIGS. 8 and 9 comprises a base pipe 68 for transporting fluids to the surface. A control valve of the downhole gravel packing apparatus comprises a flow control member 72 in the form of a tubular sleeve 72 which is located concentrically inside the base pipe 68. The control valve also comprises orifices 70 arranged through the base pipe 68 to allow fluid to enter the base pipe 68. Tubular sleeve 72 is arranged to move between a first position (as shown in FIGS. 8 and 9) in which fluid may flow through the orifices 70, and a second position in which it blocks the orifice and prevents fluid flow therethrough. The control valve is in a first configuration when the tubular sleeve 72 is in the first position and a second configuration when the tubular sleeve 72 is in the second position.

(45) Tubular sleeve 72 is acted upon by a biasing member in the form of a spring 74. The spring 74 biases the tubular sleeve 72 from the first position to the second position.

(46) Fluid reactant arrangement 76 comprises a swellable ring 78 and a snap ring 80, located at the interface between the base pipe 68 and the tubular sleeve 72. Swellable ring 78 is located at least partially in a circumferential groove in the base pipe 68 and the snap ring is located in a circumferential groove in the tubular sleeve 72.

(47) When the control valve is in the first configuration, as shown in FIGS. 8 and 9, the snap ring is located partially within the groove of the base pipe 68 and partially within the groove of the tubular sleeve 72. As such, the snap ring 80 prevents relative movement of the tubular sleeve 72 and base pipe 68 and prevents the control valve from reconfiguring to the second configuration.

(48) When the swellable ring 78 is exposed to the first fluid, it will swell. As the swellable ring 78 expands, it forces the snap ring 80 to contract. Once the snap ring 80 has contracted such that it is no longer partially located in grooves of both the tubular sleeve 72 and the base pipe 68 (i.e. once the snap ring 80 no longer protrudes into the groove of the base pipe 68), the tubular sleeve 72 is free to move relative to the base pipe 68. The control valve therefore reconfigures from the first to the second configuration as the spring 74 moves the tubular sleeve to a position where it covers the orifices 70.

(49) The downhole gravel packing apparatus of FIGS. 8 and 9 also includes a secondary sleeve 82 which is biased towards the tubular sleeve 72. The purpose of secondary sleeve 82 (and its associated spring) is to protect O-ring 84a. Several O-rings 84 are located in the downhole gravel packing apparatus in order to ensure adequate fluidic performance.

(50) Fluid channels 86 are located through the tubular sleeve 72 in order to allow fluid to escape from gaps between the tubular sleeve 72 and the base pipe 68 in order to avoid a build-up of pressure. Fluid channels 86 also provide access to the fluid reactant arrangement 76, such that the fluid reactant arrangement 76 can come into contact with the first fluid.

(51) The present invention has been described above purely by way of example. Modifications in detail may be made to the present invention within the scope of the claims as appended hereto.