Combined Fracturing Outlet and Production Port for a Tubular String

Abstract

One or more openings in a zone have an adjacent screen assembly that is axially movable to a position away from the port when pressure in the tubing exceeds the annulus pressure by a predetermined value. Upon the differential being reduced below a predetermined value or when annulus pressure exceeds the tubing pressure, the screen moves over the port to block at least some of the solids in the formation or the well fluids from entering the tubing string. The screen movement can be aided by a bias force and the movement can be locked in to prevent the screen that has moved to a position over the port from moving back away from the port.

Description

FIELD OF THE INVENTION

The field of the invention is fracturing systems that allow subsequent production through the fracture openings and more particularly an automatic way to control solids from entering during the transition time between fracturing and production.

BACKGROUND OF THE INVENTION

A variety of systems that allow fracturing ports to be opened to fracture a zone have been developed. Some of these systems also use telescoping members that extend out of the sting and across an annular gap to contact the borehole wall. In some designs the impact with the borehole wall from an extension of these telescoping passages is intended to start the fracture process which is then continued with the delivery of fluid through the ports at high velocities that result from high applied pressures. The fluid usually contains high concentration of proppants.

The openings for fracturing are preferably not obstructed with screens for handling subsequent production. As a result the designs have provided one set of ports for fracturing and another for subsequent production where a sliding sleeve or some other valve operator is used to shift between the wide open tubular ports and the production ports that have screens. However, in this arrangement there is a transition time to shift a variety of sliding sleeves from fracturing mode to production mode. In that transition time the tubing pressure can drop below the formation pressure and some solids or proppant migration can take place into the tubular string and create operational difficulties with the uphole equipment. Putting screens in the fracturing outlets provides protection against solids or proppant return flow after fracturing operation is completed. Some examples of related previous designs are U.S. Pat. Nos. 7,401,648; 7,591,312; U.S. Publication 2010/0263871and 2010/0282469.

What is needed is a system that allows a given port to be wide open for fracturing and then have a screen material move into place over the port when the fracturing is done. In a preferred embodiment the movement of the screen would be automatic and it could further be triggered by pressure reduction in the tubing string. Optionally the movement of the screen can be tied to a differential pressure between the tubing and the surrounding annulus that moves the screen. The screen can be biased to assist in the movement and the movement can be locked against a return to the former screen position. These and other advantages of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.

SUMMARY OF THE INVENTION

One or more openings in a zone have an adjacent screen assembly that is axially movable to a position away from the port when pressure in the tubing exceeds the annulus pressure by a predetermined value. Upon the differential being reduced below a predetermined value or when annulus pressure exceeds the tubing pressure, the screen moves over the port to block at least some of the solids in the formation or/and proppants in fracture from entering the tubing string. The screen movement can be aided by a bias force and the movement can be locked in to prevent the screen that has moved to a position over the port from moving back away from the port.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view showing the screen out of the way of the port during fracturing; and

FIG. 2 is the view of FIG. 1 with the tubing pressure reduced to the point that formation pressure and an optional bias force push the screen assembly into alignment with the fracturing port that can now be used for production.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a portion of a tubular string 10 that extends through a zone that is defined at opposed ends such as by packers 12 and 14 that are schematically illustrated. Although a single port 16 is illustrated in the zone 18, those skilled in the art will appreciate that multiple ports 16 and their associated equipment described below can be used. The string 10 can extend beyond zone 18 on either or both ends but such extension or extensions are omitted for greater clarity in the FIG. The port 16 can optionally have a telescoping assembly 20 that extends the outlet 22 to the borehole wall where the impact initially can cause formation fractures on extension. Pumped fluid from the surface through passage 24 as represented by arrow 26 also pushes on piston area 30 as indicated by arrows 28. The piston area 30 is preferably is just below a series of rows of ports 34. Those skilled in the art will appreciate that different styles of screens can be used such a wire wrap or Dutch Twill or simply a porous cylindrically shaped block near the piston area 30 and inside the passage 24 or an annularly shaped screen member over the ports 34 in the sleeve 32.

Sleeve 32 has an external ring 36 with an o-ring 38 against the inner wall 40 of the tubular 10. The tubular 10 has an inner ring 42 with an o-ring 44 against an outer wall 46 of the sleeve 32. As a result, there is an annular variable volume 48 with access to the formation through passage 50. Arrow 52 represents formation or surrounding annulus pressure acting in volume 48.

Biasing sleeve 52 has a biasing member such as a spring 54 supported off an internal shoulder 56 from the inside wall 40 of the tubular 10. Other biasing techniques can be used such as a stack of Belleville washers or a pressurized chamber of compressible fluid. Although sleeves 32 and 52 are shown as separate sleeves they can be one integrated sleeve as to one or a row of ports 16 or to axially spaced circumferential rows of ports 16.

The telescoping members 20 can be initially extended by fluid velocity through ports 22 or by rupture discs (not shown) that can break under pressure after the telescoping assemblies 20 fully extend and pressure continues to be built up.

Depending on the strength of the spring 54 and the pressures represented by arrows 26 and 52 the sleeves 32 and 52 will be in the FIG. 1 or FIG. 2 positions. In FIG. 2 arrow 58 represents inflow of production and fluid in the wellbore through the port 16 and the screen 33 that has automatically shifted into alignment with port 16 due to the bias of spring 54 and pressure in volume 48 from ports 50 represented by arrow 60 exceed the pressure in passage in passage 24 and the opposing force it puts on piston area 30. In FIG. 2 the piston area 62 pushing the screen 33 to the port 16 using the pressure indicated by arrow 60 and the added force from spring 54 overcomes the opposing force in passage 24 acting on the area of opposing surface 30, which is preferably the same piston area as 62. If the sleeves 32 and 52 are unrestrained during run in, the FIG. 2 position happens when pressure in the passage 24 is equal to or less than the annulus pressure outside the housing 10. As the tubing pressure rises relative to the annular pressure to overcome the force of the spring 54, such as at the start of fracturing, the sleeves 32 and 52 move the screen 33 away from port 16. If fracturing pressure is lost the screen 33 can move back to the port 16. Such opposed direction movement can be repeated unless otherwise restrained.

Spring 54 can be nested and or stacked coil springs as an option. As another option the spring 54 can be eliminated so that movement to the FIG. 2 position is just a function of pressure differential between the tubing pressure in passage 24 and the surrounding formation and well pressure in the zone 18. Alternatively, the FIG. 1 position can be held by a breakable member, not shown that is broken when the differential between formation and tubing pressure exceeds a predetermined value. As another option the sleeve 32 or 52 can have a one way ratchet (not shown) so that it will stay in the FIG. 2 position once reaching it or alternatively it will only move in the direction toward the port 16 and not in the reverse direction.

Those skilled in the art will appreciate that the movement of the screen into position by a port that had been used earlier to fracture lends many advantages. For one, the same port can be used at different times and in different conditions for fracturing and then production. Another advantage is that the system is pressure sensitive to reconfigure the fracturing ports to filtration mode on a loss or reduction of tubing pressure to a predetermined amount.

As another alternative to avoid an automatic conversion from fully open ports as in FIG. 1 to fully screened ports as in FIG. 2 when any pressure change happens, a j-slot (not shown) between the sleeves 32, 52 and the inner wall 40 of the tubular 10 can be provided. If that is done any momentary pressure loss during fracturing will not necessarily move the screen 33 into alignment with the port 16. Instead, there will need to be a defined number of pressure applications and removals using the j-slot before sufficient movement of the screen 33 occurs to place it in alignment with the port 16. Even with the j-slot the final movement of the screen 33 into alignment with the port 16 can still be a one way movement by engaging a ratchet (not shown) at the end of such movement that puts the screen 33 in alignment with the port 16.

As another configuration if the fracturing pressure is lost momentarily resulting in shifting of the screen 33 into alignment with the port 16, the pressure in the tubing passage 24 can simply be raised to reverse such movement if the fracturing process has still not been completed.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:

Claims

1. A completion apparatus for subterranean use, comprising:

a housing having an internal passage and at least one wall flow port from said passage that is automatically reconfigured as to flow restriction therethrough.

2. The apparatus of claim 1, wherein:

said port has an unrestricted configuration and a screened configuration.

3. The apparatus of claim 2, wherein:

said reconfiguration is responsive to pressure differential between said internal passage and subterranean pressure around said housing.

4. The apparatus of claim 3, further comprising:

a movably mounted screen assembly in said passage.

5. The apparatus of claim 4, wherein:

a pressure port extending through said wall of said housing and leading to a variable sealed volume between said wall and said movably mounted screen assembly.

6. The apparatus of claim 5, wherein:

screen assembly comprises a first and second opposed annular surfaces, said second annular surface defines at least a part of said variable volume.

7. The apparatus of claim 6, wherein:

said first annular surface on said screen assembly moves said screen assembly, in response to pressure in said passage, to reduce the volume of said variable volume.

8. The apparatus of claim 7, wherein:

said screen assembly is biased toward a position where said port is in said screened configuration.

9. The apparatus of claim 8, wherein:

said biasing comprises at least one of a coiled spring, Belleville washer or a compartment holding a compressible fluid.

10. The apparatus of claim 9, wherein:

said screen assembly comprises a sleeve assembly in said passage having an outer surface;

said variable volume and said biasing disposed in said housing between said sleeve and said wall.

11. The apparatus of claim 10, wherein:

said sleeve comprises a plurality of wall openings covered by at least one annularly shaped screen.

12. The apparatus of claim 11, wherein:

said at least one screen selectively aligns with at least one circumferential row of wall flow ports.

13. The apparatus of claim 10, wherein:

said sleeve assembly moves only in a direction toward putting said port in a screened configuration.

14. The apparatus of claim 10, wherein:

said sleeve assembly moves in opposed directions.

15. The apparatus of claim 10, wherein:

said sleeve is restrained with a breakable member.

16. The apparatus of claim 14, wherein:

said sleeve puts said port in said screened configuration in response to at least one pressure application and removal cycle in said passage.

17. The apparatus of claim 10, wherein:

said port further comprises a telescoping passage.

18. The apparatus of claim 8, wherein:

said bias and pressure in said variable volume against said second annular surface push said screen assembly toward a position where said port is in said screened configuration.

19. The apparatus of claim 18, wherein:

passage pressure acting on said first annular surface opposes the force of said bias and variable volume pressure on said second annular surface.

20. The apparatus of claim 1, wherein:

said at least one flow port comprises multiple flow ports in an isolated subterranean zone.