FLOW CONTROL VALVE FOR USE IN COMPLETION OF A WELLBORE

Abstract

A flow control valve (FCV) tool for a wellbore lined with a tubing string including a plurality of ports is presented. The FCV tool includes a body with a lower housing and an upper housing, the upper housing adapted to enable establishing a fluid path between the annulus of the wellbore and the plurality of ports. The lower housing and the upper housing form a pocket therebetween. The FCV valve also includes a unidirectional flow control valve designed to be received in the pocket and adapted to switch between a closed position and an open position and between the open position and the closed position based on a pressure differential between the annulus pressure and the internal pressure of the tubing string. The FCV tool enables multiple completion operations during the closed or open position of the valve.

Description

TECHNICAL FIELD

This specification is directed to improved well completion methods and tools, and in particular it proposes a one-way flow control valve for use for completing a wellbore.

BACKGROUND

After a well is drilled into a formation (reservoir) and lined, the wellbore must be ‘completed’, which involves installing a complex system of tubes and valves in or around the wellbore, called interval or flow control valves, for conveying, pumping, or controlling the injection or production of fluids, for enabling extraction of oil or natural gas from the reservoir. Flow control valves are used to control multiple zones selectively; they should reduce water cut and gas cut, minimize well interventions, and maximize well productivity.

Installing the completion equipment, as well as conducting downhole operations associated with completing the well, involve multiple runs (trips) into the well, each trip adding to the cost and complexity of the well completing operation.

Most designs use internal sleeves (also referred to as shift sleeves) that are shifted to open or close the ports to permit or prevent fluid flow through a set flow path as needed for specific completion operations. Currently, shifting tools, on coiled tubing for example, are used to allow for the system to be run in the hole with the ports in the closed position, allowing for fluid circulation from surface to the toe during run-in. Also, as most wells employ packers to isolate specific zones of the wellbore for delivery of fluids from the selected zone, keeping the ports closed allows for packer setting during completion. The downside is the need for numerous trips to run-in-hole (RIH), various tools with coil, or other methods to open the production ports for extracting the oil from the reservoir.

The invention described herein presents a solution for reducing the number of costly RIH trips. Some of the disadvantages of the current solutions are presented first.

With most current designs, an additional inner string or wash pipe is run inside the tubing string to enable a circulation path of fluid from the surface to the bottom. This additional operation also costs time and money on the rig and does not enable packer setting.

RFID (Radio Frequency Indication) technology is used sometimes to remotely communicate open and close commands to port openings of subs. The opening and closing actions can take place under battery power, the power excerpted by a ball drop action (the RFID tags would be on the ball and or a sleeve in the sub that can register passage of the ball), or other means knowns to those skilled in the art. For example, in some systems a plug with an RFID tag is launched in the wellbore, and the signals received from a preconfigured sub move it to a chosen position in the wellbore. When the plug communicates that it is in position relative to the sub, an open/close command is transmitted from the surface, after which a port sleeve of the sub is displaced to the required position. This technology alleviates use of balls seats and balls for closing/opening the ports, thus averting reductions in the internal diameter (ID) needed when ball seats are used. However, this method requires use of downhole electronics and may have limitations of time and temperature to operations if utilizing batteries.

Also known are systems where a nozzle or a tube used during completion is plugged, and the obstruction is removed when needed. In some systems, the nozzle is plugged with degradable materials. This approach raises concerns about degradation rates and unknown water saturations.

The wells that use Inflow Control Devices (ICD) to provide uniform fluid flow, particularly in formations with dynamic properties (pressure, permeability, low/high production, viscosity, etc.) currently use similar methods for run-in. The ICD systems inherently require that the circulation path from the surface to the bottom be isolated during run-in. Therefore, these systems require that an inner string/wash pipe be run inside the tubing string to allow for circulation.

There is a need for a tool which allows for fluid circulation in the tubing string system while running it in the wellbore enabling completion operations, and then allow for the system to shift into production mode without mechanical intervention.

SUMMARY

A new flow control valve (FCV) tool has been developed which enables wellbore completion without the need of running a wash pipe or an additional inner string for enabling fluid circulation inside the tubing string. By blocking the flow through the production ports, a pressure-tight flow path is created through the inner diameter (ID) of the tubing string during run-in. Isolating the inside of the tubing string from the annulus allows subsequent hydraulic completion operations such as packer and hanger setting. The FCV tool alleviates the need for a trip into the hole with a manual intervention tool to open the ports for enabling collection of the production fluid.

The proposed flow control valve (FCV) tool comprises a flow control valve, also referred to as an FCV, or as a valve herein, which covers the ports to ensure that no fluid pumped from the surface can exit through the ports over which it is placed during run-in-hole (RIH) and other completion operations. In one embodiment the valve is a check valve or a valve implementing a unidirectional flow. The valve seals the internal higher pressure from the lower annular pressure, allowing fluid to flow inside the tubing string ID, and not allowing fluid to flow from the ID to the annulus. Once the well is ready to be put on production, a decrease of pressure within the tubing string simultaneously opens the valves providing access to the ports. The valve can be used to close and open the ports by changing the difference between the internal pressures.

In one embodiment, the valve has a limited life and it degrades (e.g. dissolves) after a certain time. However, the valve may be constructed from a non-degradable material and used for one-way isolation of the inside of the tubing string as needed.

It is also to be noted that the FCV can be used to block any ports in the tubing string as needed.

It is also to be noted that the FCV can be used, for example, for ICD completions or standard on-off screen assemblies. Other uses may be envisaged. For an ICD completion, the FCV tool can be incorporated with an ICD. The FCV tool can also be used in a variety of other production valve configurations such as on/off screen, ICD applications etc.

To summarize, conventional systems rely on well intervention trips (e.g. with manual shifting tools) to open or close the ports between the ‘packer setting’ and ‘open to production’ modes of the system. In contrast, use of the FCV tool requires a low differential pressure to open the ports, and has the ability to open/close the ports multiple times by adequately manipulating the internal pressure. This is a significant advantageous feature of the proposed flow control valve. The temporary nature of the valve is also an advantage in some embodiments, because systems that do not have this functionality require additional trips with a service tool. The temporary nature of the valve prevents the need to complete an intervention trip later in the well life.

Another advantage of the embodiments described in this specification is that they enable an operator to control simultaneous operation of all ports from surface by decreasing the internal pressure by a relatively small value to open the ports, and increasing the internal pressure by a relatively small value to close the ports.

Accordingly, a flow control valve (FCV) tool for a wellbore lined with a tubing string including a plurality of ports is proposed in this specification. The FCV tool comprises: a body with a lower housing and an upper housing, the upper housing adapted to enable establishing a fluid path between the annulus of the wellbore and the plurality of ports; a pocket formed between the lower housing and the upper housing; and a unidirectional flow control valve designed to be received in the pocket and adapted to switch between a closed position and an open position and between the open position and the closed position based on a pressure differential between the annulus pressure and the internal pressure of the tubing string, wherein multiple completion operations are enabled during the closed or open position of the valve.

In another embodiment, a method of completing a wellbore for fluid extraction is described in this specification. The method comprises running in a tubing string having a plurality of ports and a toe circulation sub, the tubing string being equipped with a flow control valve (FCV) tool, maintaining the FCV tool in the closed position to block fluid from entering the tubing string through the plurality of ports, while enabling fluid circulation in the tubing string through the toe circulation sub, closing the toe circulation sub and performing multiple completion operations which require an internal pressure higher that the annulus pressure; and decreasing the internal pressure to a first threshold differential, so as to open the FCV tool and allow fluid circulation from the annulus to the inner diameter of the tubing string.

Other aspects of this invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

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 with reference to the drawings. The drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. Embodiments of the present invention will now be described, by way of example only, with reference to the attached figures:

FIG. 1 is a perspective view of the flow control valve (FCV).

FIG. 2 shows the tubing string with the flow control valve tool in a closed position and the shift sleeve in the port open position.

FIGS. 3A and 3B show the flow control valve in more detail. In FIG. 3a the flow control valve tool is in the closed position and in FIG. 3b the flow control valve tool is in the open position.

FIG. 4 illustrates the tubing string with an FCV tool in an open position and the shift sleeve in the open position.

FIG. 5 shows the tubing string with the FCV tool and the shift sleeve in the close position.

As will be realized by a person skilled in the art, different embodiments are also possible, and several details of each embodiment are capable of modification in various respects, all within the scope of the present invention.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

It should be noted that terms “upper,” “back” and “rear” are used to refer to being on or closer to the surface side (upwell side) relative to a corresponding feature that is “lower,” “forward” or “front”. For example, an “upper” end of a tubular component generally refers to the feature relatively closer to the surface than a corresponding “lower” end. A feature that may be referred to as an “upper” feature relative to a “lower” feature even if the features that are vertically aligned may occur, for example, in a horizontal well. Similarly, the terms “uphole,” “up,” “downhole” and “down” refer to the relative position or movement of various tools or objects, features, with respect to the wellhead. These terms are used similarly in horizontal wells.

In this specification, the pressure outside of the tubing string placed inside a wellbore is referred to as the “annulus pressure”, and the pressure inside the tubing string is referred as the “internal pressure”.

FIG. 1 illustrates flow control valve (FCV) 10. The valve is ring shaped and has a main body 5 and a profile 2, also referred to as ‘a rim’, at a first end 6. The second end is denoted with 4. Preferable, FCV 10 is designed to hold pressure from ID to annulus. As an example, the valve will hold 4000 psi for up to 36 hours.

For the direction of the flow from the annulus to the inside of the string, the valve is designed to:

(a) isolate the internal diameter of the tubing string from the annulus when the internal pressure is higher than the annulus pressure,

(b) collapse at the second end 4 when the annulus pressure is higher than the internal pressure, allowing the fluid to enter the string through ports 11, and,

(c) degrade and disappear (e.g. dissolve itself) over a period of time, leaving the ports open.

It is to be understood that the above parameters depend on the material used for the valve 10. Preferably, the valve 10 should be constructed from various materials ranging from polymers to elastomers to degradable materials with supporting rings.

An FCV tool 100, comprising a flow control valve 10, is placed around the tubing string 3 as seen in FIG. 2, and next explained. FCV tool 100 includes a body made of an upper housing 30 and a lower housing 20 which overlap partially to provide a pocket 17 therebetween. A shift sleeve 12, which is a conventional sleeve that can be actuated by any known means to close or open the ports 11 by sliding to expose or cover the ports 11 of the tubing string, is also illustrated. Sleeve 12 has one or more openings 13. In FIG. 2, sleeve 12 is illustrated in an open position (i.e., shift sleeve openings 13 correspond to ports 11 of the tubing 3. However, the ports 11 are still closed by the valve 10 interposed between the ports 11 and the openings 13.

The pocket 17 has an end wall 18 at its upper end. The pocket 17 is sized to receive the flow control valve 10 with the first end 4 abutting on wall 18. At the lower end of the pocket 17, the rim 2 provided at the second end 6 of the valve 10 is attached to the lower housing 20 as shown. The external wall of the pocket made by the upper housing 30 has a plurality of ports 19 provided on its circumference. The ports 19 in the upper housing 30 are formed over an area corresponding to the area of the tubing string 3 that has the ports 11, so that these two areas overlap, and are isolated from one another when the FCV tool 100 is installed on the tubing string and in the closed position, as shown on FIG. 2.

It is to be noted that ports 19 could be of different shapes and sizes, such as holes, or channels.

When FCV 100 is deployed around the tubing string 3, valve 10 is sandwiched between the portion of the upper housing that has the ports 19, and the area with the ports 11 on the tubing string. When the internal pressure is greater than the annulus pressure, the valve 10 blocks the flow between ports 11 and 19 in the direction from the inner diameter of tubing 3, to the annulus, so that the fluid stays inside the tubing.

As indicated above, in FIG. 2, shift sleeve 12 is in the open position, with the openings 13 over ports 11. In this view, the valve 10 is in the closed position, covering the ports 11 as can be seen through opening 13 in the shift sleeve 12.

FIGS. 3A and 3B show the FCV tool 100 in more detail.

In FIG. 3A the flow control valve tool 100 is in the closed position. As seen, the valve 10 is placed between the port 19 of the upper housing 30 and the port 11 of the tubing string 3. In the closed position, the inner diameter (ID) pressure is maintained above the annulus pressure, the valve is decompressed and the main body 5 of the FCV 10 closes the ports enabling completion operations to take place by isolating the ID from the annulus. This pressure difference keeps ports 11 closed to flow circulation in both directions, to and from the inside of the tubing 3. The specification uses the term “closed position of the FCV” for this state.

When the internal pressure in the tubing string 3 is decreased below the annulus pressure by a first threshold differential pressure, the fluid from the annulus pushes the valve 10 into the open position, as squeezable valve 10 is compressed, enabling the fluid to enter the internal diameter. This results in an instantaneous flow of fluid from the annulus to the inside of the liner through the ports. Conventional tools require pressure to shear pins and collapse springs in order to displace any port closing device/sleeve for enabling fluid flow through the ports. An FCV, by contrast, merely requires a pre-defined and smaller threshold pressure differential to be applied from surface.

FIG. 3B shows the valve in the open position, for which the term “open position of the FCV” is used. As indicated before, the open and closed positions of the valve are controlled from surface during well completion. The FCV tool 100 can be used for opening and closing any port type, as apparent to those skilled in the art.

As seen in FIG. 3B, once the annulus pressure becomes greater than the internal pressure by a ‘second threshold differential pressure’, the first end 4 of the valve 10 is pushed into the pocket 17 as shown, the second end 6 being kept in a fixed position at the attachment with the lower housing 20. In this way, a channel opens for a flow from the annulus to the inside of the tubing string, as shown by the arrows in FIG. 3B. The ports can be closed back by increasing the internal pressure, and the close/open operations can be repeated as needed.

In embodiments of the invention, the FCV 10 is degradable, which means the operation of the FCV 10 is time dependent; ports 11 remain open after the valve 10 degrades.

Embodiments where the valve does not degrade are also possible and may be needed in wells where future stimulation isn't required or where cross flow between reservoirs may occur.

As indicated above, closing and opening the ports with FCV tool 100 can be done by changing the internal pressure to obtain a desired pressure differential between the annulus pressure and the internal pressure. Manipulating the pressure differential from the surface controls simultaneous operation of all ports.

To summarize, running the FCV tool with the FCV 5 in the well results in sealing flow from the internal diameter (ID) to the annulus. As shown in FIGS. 2 and 3A in this state, the fluid cannot exit the ports, which are covered by the valve 10. As a result, all flow goes out the toe of a tubing string through a float shoe and toe circulation sub (not shown), and as indicated above, production ports are closed because of a higher internal pressure and a lower annulus pressure.

FIG. 4 illustrates the tubing string with an FCV tool 100 in the open position and the shift sleeve 12 also in the open position. In this case, the fluid flows from the annulus into the tubing string 3 as shown by the arrows, since the annulus pressure is greater than the internal pressure.

FIG. 5 shows the tubing string with the FCV tool 100 and the shift sleeve 12 in the closed position. As indicated above, sleeve 12 can be used to open and close ports 11 as known, once the FCV is in the open position or degraded/dissolved.

The completion operations of the wellbore are described next. The tubing/casing 3 is equipped with a toe circulation sub in the open position, and is maintained in that position for a run-in-hole (RIH) operation. Once the RIH operation is complete, and the system is on depth, the toe circulation sub is shifted closed, using for example a ball launched from surface or other known means. The tubing string is now isolated from the annulus, which allows for pressure build-up to set tubing string hangers, the packers and/or other isolation devices if required.

Thereafter, the FCV tool 100, which was run into the wellbore attached to the tubing/casing 3 as part of the RIH operation, is actuated by increasing the internal pressure until it is above the annulus pressure by some predefined threshold (the second threshold differential). This results in the valve 10 sealing all production ports 11 to stop any flow from the inner diameter (ID) to the annulus, as shown in FIGS. 2 and 3A. By isolating the inner diameter of the tubing string 3 from the annulus, the pressure can be further increased to set the packers and the liner hangers. Other operations that require having the inner diameter sealed may also be performed, such as deploying tools and cementing.

The FCV tool 100 can be switched closed or open as needed without additional run-in-hole (RIH) operations, resulting in important savings in time and money and important reduction of operational risk.

When the well is ready for production, a decrease in internal pressure below the pressure of the annulus allows the one-way valve to open, to allow immediate unencumbered flow from the annulus to the tubing string ID as shown in FIGS. 3B and 4. By lowering the pressure, all valves 10 are unset at the same time, which shortens the time needed to prepare the well for production.

The temporary existence of the valve 10 is advantageous for the performance of the tool 100. As indicated above, in one embodiment the valve degrades or erodes over time (without operator intervention) to ensure full access to the reservoir for future stimulation activities.

Claims

1. A flow control valve (FCV) tool for a wellbore lined with a tubing string including a plurality of ports, comprising: a body with a lower housing and an upper housing, the upper housing adapted to enable establishing a fluid path between the annulus of the wellbore and the plurality of ports;a pocket formed between the lower housing and the upper housing; anda unidirectional flow control valve designed to be received in the pocket and adapted to switch between a closed position and an open position and between the open position and the closed position based on a pressure differential between the annulus pressure and the internal pressure of the tubing string,wherein multiple completion operations are enabled during the closed or open position of the valve.

2. The FCV tool of claim 1, wherein in the closed position, the flow control valve seals the fluid path, to enable the multiple completion operations without the need for additional run-in-hole trips.

3. The FCV tool of claim 1, wherein in the open position the flow control valve opens the fluid path to enable extraction of production fluids.

4. The FCV tool of claim 1, wherein the multiple completion operations include setting one or more packers.

5. The FCV tool of claim 1, wherein the multiple completion operations include setting one or more liner hangers.

6. The FCV tool of claim 1, wherein the fluid path includes a plurality of housing ports provided in the upper housing for enabling fluid circulation between the annulus and the tubing string when the flow control valve is in the open position.

7. The FCV tool of claim 1, wherein the plurality of ports open simultaneously when the pressure in the tubing string is lowered below the pressure in the annulus by a first threshold differential pressure.

8. The FCV tool of claim 1, wherein the plurality of ports are maintained closed when the pressure in the ID of the tubing string is higher than the pressure in the annulus by a second threshold differential pressure, while the flow control valve is in the closed position.

9. The FCV tool of claim 1, wherein the flow control valve comprises a first and a second end, wherein a rim provided at the second end enables attachment of the valve to the lower housing, when the valve is installed in the pocket.

10. The FCV tool of claim 10 wherein the first end is deflected by a higher annulus pressure higher than the internal pressure to open the fluid path.

11. A method of completing a wellbore for fluid extraction, comprising running in a tubing string having a plurality of ports and a toe circulation sub, the tubing string being equipped with a flow control valve (FCV) tool,maintaining the FCV tool in the closed position to block fluid from entering in the tubing string through the plurality of ports, while enabling fluid circulation in the tubing string through the toe circulation sub,closing the toe circulation sub and performing multiple completion operations which require an internal pressure higher that the annulus pressure; anddecreasing the internal pressure to a first threshold differential, so as to open the FCV tool and allow fluid circulation from the annulus to the inner diameter of the tubing string.

12. The method of claim 11, further comprising increasing the internal pressure over a first threshold differential to close the FCV tool and disallow fluid circulation from the annulus to the inner diameter of the tubing string.

13. The method of claim 11, wherein the FCV tool has a temporary unidirectional flow control valve which degrades after a period of time.

14. The method of claim 13, further comprising closing and opening the plurality of ports with a shift sleeve after the flow control valve degrades.