GB2583156A

GB2583156A - Flow diverter valve

Info

Publication number: GB2583156A
Application number: GB1915670.2A
Authority: GB
Inventors: S Lamont Paul; Ritchie Lee
Original assignee: Ums Flowell Assets Ltd
Current assignee: Ums Flowell Assets Ltd
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2020-10-21
Anticipated expiration: 2039-10-29
Also published as: GB201915670D0; GB2583156B

Abstract

A flow diverter valve for use with an electric submersible pump (ESP) system comprises a body with a bore, the body comprising at least one radial port 53, 55 extending through a side wall of the body and a shuttle 50 slidable within the bore of the body between a first position for restricting the bore flowpath and diverting fluid flow through the radial port 53, 55, and a second position for closing the radial flowpath and opening the bore flowpath; wherein a collar 60 of the shuttle extends into a sealed chamber between the shuttle and the body, and divides the sealed chamber into first and second cavities; wherein the valve incorporates first and second biasing devices adapted to urge the shuttle toward the first position; and wherein the valve incorporates a fluid conduit (Fig 5c, Fig 5D) to permit fluid flow across the collar between the first and second cavities.

Description

FLOW DIVERTER VALVE

The present invention relates to a flow diverter valve for use in an oil and gas well, particularly to a flow diverter valve adapted for use with an electrical submersible pump (ESP) system.

Background to the Invention

Electrical submersible pump (ESP) systems are a form of artificial lift system that can be deployed in the bore of oil and gas wells to improve and control the flow of fluids from the downhole formation to the surface. ESP systems are often used to compensate for low reservoir pressure in mature wells.

The service life of ESPs can be limited, and retrieval to the surface in order to repair, overhaul or replace a failed ESP can be difficult and time-consuming. ESPs are often deployed in sets of two or more, to provide redundancy, for this reason.

Known flow diverter valves maximise ESP lifetime by allowing formation fluids under sufficient pressure, for example in new wells, to enter the bore of the production tubing above one or more ESPs and flow naturally to the surface without assistance from the ESPs, which can remain inactive during that phase. The ESPs can optionally be activated later in the life of the well e.g. when required to improve flow rate and / or pressure to the surface. Known flow diverter valves also allow fluid that remains in the production tubing above an inactive ESP to be diverted from the bore of the tubing (and the outlet of the ESP) to the annulus outside the production tubing.

This prevents fluid flowing back through the inactive ESP when draining the production tubing, which reduces wear on the ESP and reduces the accumulation of debris or solids flowing through the ESP, which can cause damage to ESP components.

Examples of known designs of flow diverter valves are shown in GB 2411416 and US 7,900,707, which are useful for understanding the present invention.

Summary

According to the present invention, there is provided a flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system; and a shuttle slidable axially within the bore of the body between first and second positions; wherein in the first position, the shuttle engages a seat in the bore to restrict the bore flowpath and diverts fluid flow through a bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, and wherein the valve incorporates a fluid conduit to permit fluid flow across the collar between the first and second cavities.

The combined volume of the first and second cavities, and therefore the overall volume of the sealed chamber, can remain substantially unchanged when the shuttle is moving. Optionally the volume of the sealed chamber is independent of the position of the shuttle; in other words, as the shuttle slides in a first axial direction relative to the body, and correspondingly as the collar moves in the same first axial direction through the sealed chamber, the volume of the sealed chamber remains constant. Optionally, as the shuttle is moving, the rate of decrease in volume of the first cavity can be equivalent to the rate of increase in volume of the second cavity. Conversely, as the shuttle slides in a second opposing axial direction relative to the body, and correspondingly as the collar moves in the same second axial direction through the sealed chamber, the rate of increase in volume of the first cavity can be equivalent to the rate of decrease in volume of the second cavity. Optionally the pressure in both the first and second cavities can remain substantially equal as the shuttle slides axially relative to the body, which prevents any significant pressure differential developing across the collar of the shuttle, which would impede or prevent free axial movement of the shuttle.

Optionally the sealed chamber does not require any venting to, for example, the annulus of the well or the bore of the body, in order to balance pressure across the collar as the shuttle slides axially and as the volume of the first and second cavities increases and decreases. Such vents must be meshed or otherwise capable of filtering fluid as it flows in or out of the chamber, to prevent the ingress of debris or other contaminants into the chamber, which can leave the vents prone to partial or complete blockages. Also, any filter devices in the vents may be dislodged or ruptured by any rapid pressure change in the chamber caused by sudden movement of the shuttle and collar. If this occurs, debris can enter the chamber can begin to accumulate in the cavity, eventually impeding or preventing free axial movement of the shuttle.

The bore of the body optionally has multiple portions defined by different internal diameters. A central portion optionally has a larger diameter than at least one end portion. The shuttle optionally comprises a sleeve disposed within the central portion of the bore of the body. Optionally the shuttle is slidable within the larger bore of the central portion. Optionally the outer diameter of the shuttle is greater than the inner diameter of the at least one end portion of the bore; thus the sliding movement of the shuttle within the central portion is optionally limited by at least one shoulder extending radially into the bore and defining a boundary between the central portion and at least one end portion (optionally both end portions). Optionally the shuttle makes a sliding fit with the inner surface of the central portion of the bore of the body. Typically the outer diameter of the shuttle is a sliding fit within the inner diameter of the central portion of the bore of the body. Optionally the axial length of the large diameter central portion defines the maximum extent of permitted sliding movement of the shuttle within the bore of the body between the first and second positions of the shuttle.

The central portion of the bore of the body optionally comprises an expanded portion, which optionally has a larger inner diameter than the nominal inner diameter of the central portion of the bore. Typically the collar has a radially outer face which has a variable diameter. Optionally the greatest outer diameter of the outer face of the collar is a sliding fit within the inner diameter of the expanded portion. Optionally the outer surface of the shuttle overlaps with the expanded portion in an axial direction to form a closed chamber, optionally an annular chamber which optionally surrounds the shuttle. Optionally the shuttle axially overlaps with the expanded portion when the shuttle is in the first and second positions; in other words, whether the shuttle is in the first or the second position, the expanded portion is optionally bounded on its inner surface by the shuttle, which extends axially beyond the axial ends of the expanded portion in both the first and second position of the shuttle. Optionally the closed chamber comprises the sealed chamber.

Optionally the collar of the shuttle comprises a protrusion or flange which extends (optionally radially) from the outer surface of the shuttle. Optionally at least a portion of the collar extends circumferentially around the outer surface of the shuttle, and optionally surrounds the shuttle. The collar is optionally annular. Optionally the sliding movement of the collar (and optionally of the shuttle) is limited by a shoulder disposed at least at one axial end of the sealed chamber which optionally provides a stop for the collar.

Optionally the collar comprises first and second opposing end walls, which are optionally mutually parallel. Optionally the end walls are perpendicular to the axis of the shuttle, and optionally the end walls on opposing sides of the collar face in opposing axial directions through the sealed chamber. The collar optionally further comprises a circumferential rim, which is optionally parallel to the axis of the shuttle, disposed between and optionally connecting the end walls.

Optionally the circumferential rim of the collar comprises first and second portions which have different diameters. Optionally first and second portions alternate circumferentially around the rim. Optionally first portions of the rim are generally arcuate. Optionally second portions of the rim are generally flattened. Typically the first (arcuate) portions of the rim are matched to the inner surface of the sealed chamber. Optionally the first (arcuate) portions of the circumferential rim contact the inner surface of the sealed chamber, and optionally make a sliding fit with the inner surface of the sealed chamber. Optionally the second (flattened) portions of the circumferential rim make a clearance fit with the inner surface of the sealed chamber, in that they optionally diverge from the inner surface of the sealed chamber. Optionally the surface area of the first and second end walls of the collar is less than the area of the annulus between the outer surface of the shuttle and the inner surface of the sealed chamber.

Optionally the first and second end walls of the collar incorporate one or more apertures or ports which extend axially between the first and second end walls.

Optionally the one or more ports are disposed symmetrically around the axis of the bore of the shuttle, optionally at regular intervals.

As the shuttle slides axially between the first and second positions in the central portion of the bore of the body, the collar moves axially within the sealed chamber.

Optionally the fluid conduit permits fluid flow from the first (upper) cavity to the second (lower) cavity when the shuttle moves in an upward axial direction relative to the body (i.e. toward the surface), and optionally the fluid conduit permits fluid flow from the lower cavity to the upper cavity when the shuttle moves in an opposing downward axial direction (i.e. away from the surface).

Optionally the volume of the upper cavity decreases and the volume of the lower cavity increases in proportion as the shuttle moves from the first position toward the second position. Optionally the volume of the upper cavity increases and the volume of the lower cavity decreases in proportion as the shuttle moves from the second position toward the first position. Optionally the combined volume of the first and second cavities remains approximately constant while the shuttle is moving, and the volume is the same when the shuttle is in the first position as it is when the shuttle is in the second position.

Optionally the fluid flow between the upper and lower cavities as the shuttle moves between the first and second positions is evenly distributed around the axis of the bore of the shuttle. Optionally the total area of the flow path of the fluid conduit available for fluid flow between the upper and lower cavities is distributed equally (optionally symmetrically) around the axis of the bore of the shuttle. Optionally the total surface area of the fluid conduit is within 30-80% of the total surface area of one of the end walls of the collar.

Optionally the first biasing device urges the shuttle toward the first position when the shuttle is in any axial position relative to the body, and optionally the second biasing device urges the shuttle toward the first position as the shuttle approaches the first position, and optionally when the shuttle is in the first position.

Optionally the first and second biasing devices exert a force on the shuttle (optionally on the collar of the shuttle), optionally in the same (optionally downward) direction.

Optionally the first biasing device exerts a compressive force on the collar, and optionally the second biasing device exerts a tensile force on the collar. Optionally the first biasing device pushes against an (optionally upper) end wall of the collar, and optionally the second biasing device pulls on the opposing (optionally lower) end wall of the collar.

Optionally the first biasing device comprises a resilient member, optionally a spring. Optionally the second biasing device comprises a magnetic device.

Optionally the force exerted by the spring decreases (optionally gradually, optionally linearly) as the shuttle approaches the first position. Optionally the force exerted by the magnetic device increases (optionally rapidly, optionally exponentially) as the shuttle approaches the first position. Optionally the maximum force exerted by the spring (optionally when the shuttle is in the second position) is less than the maximum force exerted by the magnetic device (optionally when the shuttle is in the first position).

Optionally the spring surrounds the shuttle, and optionally the spring contacts the outer surface of the shuttle. Optionally the outer diameter of the spring is less than the inner diameter of the expanded portion of the bore, such that the spring is radially spaced from the inner surface of the expanded portion. Therefore, the lower axial end of the spring typically does not occlude the gaps between the flattened portions of the rim of the collar and the inner surface of the expanded portion.

Optionally the magnetic device exerts a magnetic force on the shuttle, optionally on the collar of the shuttle. Optionally the magnetic device is annular, and optionally surrounds the shuttle. Optionally the magnetic device is disposed within the sealed chamber, optionally adjacent to the lower axial end of the sealed chamber.

Optionally the collar of the shuttle approaches, and optionally contacts, the magnetic device when the shuttle is in the first position. Optionally the magnetic device comprises a plurality of magnetic elements. Optionally the magnetic elements are arranged circumferentially around a side wall of the magnetic device. Optionally the magnetic elements are arranged regularly (optionally symmetrically) around the magnetic device, and optionally adjacent magnetic elements are regularly spaced.

Optionally the magnetic elements have non-uniform radial spacing from the centre of the magnetic device. Optionally the magnetic elements which are aligned with the arcuate portions of the collar are closer to the rim of the magnetic device than the magnetic elements which are aligned with the flattened portions of the collar.

Optionally the magnetic elements are orientated such that one or more magnetic elements have a North pole facing the collar of the shuttle, and one or more magnetic elements have a South pole facing the collar of the shuttle. Optionally the magnetic elements are arranged such that adjacent magnetic elements have opposing magnetic polarity.

Optionally the shuttle moves away from the first position when the pressure in the second portion of the bore is greater than the pressure in the first portion of the bore, and optionally when the pressure differential between the first and second portions of the bore is greater than a threshold pressure differential. Optionally the shuttle remains in the second position when the rate of fluid flow from the second portion of the bore to the first portion of the bore is greater than a threshold fluid flow rate. Optionally the shuttle moves away from the second position when the rate of fluid flow from the second portion of the bore to the first portion of the bore is less than the threshold fluid flow rate. Optionally the shuttle remains in the first position when the pressure differential between the first and second portions of the bore is less than the threshold pressure differential.

Optionally the threshold pressure differential between the first and second portions of the bore (above which the shuttle optionally moves away from the first position), is approximately equal to the combined biasing force of the first and second biasing devices when the shuttle is in the first position.

Optionally the shuttle comprises a closure device, optionally a valve, optionally a flapper valve. Optionally the flapper valve is disposed within a reduced inner diameter portion of the bore of the shuttle. Optionally the flapper moves (optionally rotates, optionally pivots) between a closed position, in which the flapper occludes the bore of the shuttle, and an open position, which optionally opens a flow path through the bore of the shuttle. Optionally the closure device incorporates a biasing device, optionally a torsion device, optionally a spring, which optionally urges the flapper toward the closed position. Optionally fluid flow through the bore of the shuttle from the lower end of the shuttle toward the upper end of the shuttle urges the flapper from the closed position toward the open position, in opposition to the biasing force of the biasing device. Optionally fluid flow through the bore of the shuttle from the upper end of the shuttle toward the lower end of the shuttle is prevented when the flapper is in the closed position. Optionally the flapper valve comprises a sealing face adapted to form a seal, optionally a metal-to-metal seal, when the sealing face lands on a corresponding seat disposed on the reduced inner diameter portion of the bore of the shuttle.

Optionally fluid in the bore of the body above the flapper, and in tubing joined to the upper end of the flow diverter valve, exerts a downward force (optionally due to gravity acting on the fluid) on the flapper when the flapper is in the closed position. Optionally the downward force exerted on the shuttle by the flapper in the closed position in complements the force exerted by the first and second biasing devices on the shuttle, urging the shuttle into the first position.

Optionally the shuttle comprises one or more radial fluid ports which are axially aligned with the one or more radial ports of the body when the shuttle is in the first position. Optionally the flapper is disposed adjacent to the shuttle fluid ports, optionally below the shuttle fluid ports. Optionally the flapper prevents fluid flow from above the shuttle (optionally from above the flow diverter valve) from entering a lower portion of the shuttle below the flapper. Optionally the flapper prevents debris (optionally solids, optionally particulates, optionally granular material) from entering the lower portion of the shuttle. Optionally fluid flow out of the one or more radial fluid ports of the shuttle carries (optionally flushes) debris out of the shuttle. Optionally debris in the fluid is prevented from accumulating or settling on or adjacent to the flapper by fluid flow out of the one or more radial fluid ports of the shuttle.

Optionally the closure device remains in the first position until after the shuttle has moved axially into the second position from the first position, and optionally the closure device moves into the first position before the shuttle moves axially away from the second position toward the first position. Optionally the closure device moves between the first and second positions when the shuttle is in the second position. Optionally the closure device moves between the first and second positions when the first biasing device (e.g. the spring) exerts a force on the shuttle approaching a maximum force on the shuttle, and optionally when the first biasing device urging the movement of the shuttle has started to release potential energy. Optionally the closure device closes as the shuttle is moving from the second position to the first position, optionally immediately after a change of direction of the shuttle to move towards the first position from the second position. Optionally the closure device biasing device is relatively stronger than the first biasing device. Optionally the closure device is in the first position when the one or more shuttle ports are axially aligned with the one or more body ports, and optionally the shuttle ports are axially spaced from the body ports (optionally sealing the bore of the shuttle from the outer surface of the body) when the closure device is in the second position.

The present invention also provides a flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system; a shuttle slidable axially within the bore of the body between first and second positions; and a closure device disposed within a bore of the shuttle; wherein in the first position, the shuttle engages a seat in the bore of the body to restrict the bore flowpath and diverts fluid flow through the bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein a first portion of the collar makes a sliding fit with an inner surface of the body and a second portion of the collar makes a clearance fit with the inner surface of the body, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, wherein the closure device is adapted to move between a first position in which fluid flow through the bore of the shuttle is substantially prevented, and a second position in which fluid flow through the bore of the shuttle is permitted, and wherein the second portion of the collar permits fluid flow across the collar between the first and second cavities.

The present invention also provides a flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system; a shuttle slidable axially within the bore of the body between first and second positions; and a closure device disposed within a bore of the shuttle; wherein in the first position, the shuttle engages a seat in the bore of the body to restrict the bore flowpath and diverts fluid flow through the bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, wherein the first biasing device comprises a resilient member and the second biasing device comprises a magnetic device, wherein the closure device is adapted to move between a first position in which fluid flow through the bore of the shuttle is substantially prevented, and a second position in which fluid flow through the bore of the shuttle is permitted, wherein the closure device incorporates a third biasing device adapted to urge the closure device toward the first position, wherein the third biasing device is relatively stronger than the first biasing device, and wherein the valve incorporates a fluid conduit to permit fluid flow across the collar between the first and second cavities.

The present invention also provides a method of diverting fluid flow in an oil or gas well incorporating an electric submersible pump (ESP) system with a flow diverter valve, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a ESP tubular string in an oil or gas well; and a shuttle slidable axially within the bore of the body between first and second positions; wherein in the first position, the shuttle engages a seat in the bore to restrict the bore flowpath and diverts fluid flow through a bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between the first portion of the bore and a second portion of the bore below the seat, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, wherein the method includes flowing fluid through a fluid conduit across the collar between the first and second cavities when the shuttle is moving between the first and second positions.

The various aspects of the present invention can be practiced alone or in combination with one or more of the other aspects, as will be appreciated by those skilled in the relevant arts. The various aspects of the invention can optionally be provided in combination with one or more of the optional features of the other aspects of the invention. Also, optional features described in relation to one aspect can typically be combined alone or together with other features in different aspects of the invention. Any subject matter described in this specification can be combined with any other subject matter in the specification to form a novel combination.

Various aspects of the invention will now be described in detail with reference to the accompanying Figures. Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the Figures, which illustrates a number of exemplary aspects and implementations. The invention is also capable of other and different examples and aspects, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, each example herein should be understood to have broad application, and is meant to illustrate one possible way of carrying out the invention, without intending to suggest that the scope of this disclosure, including the claims, is limited to that example. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. In particular, unless otherwise stated, dimensions and numerical values included herein are presented as examples illustrating one possible aspect of the claimed subject matter, without limiting the disclosure to the particular dimensions or values recited. All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein are understood to include plural forms thereof and vice versa.

Language such as "including", "comprising", "having", "containing", or "involving" and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Thus, throughout the specification and claims unless the context requires otherwise, the word "comprise" or variations thereof such as "comprises" or "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Any discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention.

In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting essentially or, "consisting", "selected from the group of consisting of", "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words "typically" or "optionally" are to be understood as being intended to indicate optional or non-essential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention.

References to directional and positional descriptions such as upper and lower and directions e.g. "up", "down" etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee. References to "up" or "down" will be made for purposes of description with the terms "above", "up", "upward", "upper", or "upstream" meaning away from the bottom of the well and toward the surface, and "below", "down", "downward", "lower", or "downstream" meaning toward the bottom of the well and away from the surface and deeper into the well, whether the well being referred to is a conventional vertical well or a deviated well and therefore includes the typical situation where a rig is above a wellhead, and the well extends down from the wellhead into the formation, but also horizontal wells where the formation may not necessarily be below the wellhead.

In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce the desired results.

Brief Description of the Drawings

In the accompanying drawings: Figure 1 is an external perspective view of an example of a flow diverter valve; Figure 2 is a front section view of the magnetic ring of the flow diverter valve shown in Figure 1; Figures 3a to 3e are side section views of the flow diverter valve shown in Figure 1, which illustrate the sequence of the shuttle sliding from the first to the second position and the flapper opening in response to positive fluid flow from an activated ESP below the flow diverter valve, and the flapper closing and the shuttle sliding from the second to the first position when the ESP becomes inactive.

Figures 4a and 4b are detailed side section views of the sealed chamber of the flow diverter valve shown in Figure 1, which illustrate the shuttle in the first and second positions respectively; Figures 5a and 5b are side and front elevations of the body and the collar of the shuttle respectively; and Figures 5c and 5d are detailed side section views of the sealed chamber of the flow diverter valve shown in Figure 1, which illustrate fluid flow between the first and second cavities as the shuttle approaches and leaves the second position.

Detailed Description

Referring now to the drawings, a first example of a flow diverter valve 1 in accordance with the invention is shown in Figure 1. In this example the body of the flow diverter valve 1 comprises an upper sub 10, an intermediate housing 20, and a lower sub 30. The upper sub 10 is closest to the surface of the well, while the lower sub 30 is furthest from the surface of the well. The skilled reader will appreciate that "upper" and "lower" are useful non-limiting designations that are not intended to limit the present disclosure to exclude e.g. horizontal wells where the toe of production tubing incorporating the flow diverter valve 1 may not be below the wellhead.

Each of the upper sub 10, housing 20 and lower sub 30 are generally cylindrical and each has a bore with an axis. The upper sub 10, housing 20 and lower sub 30 are typically joined together by locking anti-rotation devices, which in this example comprise threaded lock ring assemblies 19, 39. Each threaded lock ring assembly 19, 39 comprises an anti-rotation clutch ring adapted to prevent relative rotation of the upper sub 10 and the housing 20, and of the housing 20 and the lower sub 30, and a threaded lock ring for restricting axial movement of the clutch ring. The upper sub 10, housing 20 and lower sub 30 are therefore rigidly connected together. When assembled, the housing 20 is disposed axially intermediate the upper and lower subs 10, 30, and the axes of the upper sub 10, housing 20 and lower sub 30 are optionally coaxial, forming a single bore lb through the flow diverter valve 1. Also in this example a shuttle 50 is disposed within the bore 1 b of the flow diverter valve 1, and is axially slidable therein between a first position in which the shuttle 50 is closer to the lower axial end of the flow diverter valve, and a second position in which the shuttle is closer to the upper axial end of the flow diverter valve.

In this example the upper axial end of the bore of the upper sub 10 is counterbored and threaded to form, for example, box and pin connections to allow the flow diverter valve 1 to be connected to a tubular string, for example production tubing installed above an ESP system. The opposing lower axial end of the bore of the upper sub 10 is also counterbored to provide an enlarged bore portion, and the corresponding outer surface of the upper sub comprises a reduced diameter portion (see Fig 3a,b). The enlarged bore portion and reduced diameter portion form respective inner and outer shoulders 14, 15 on the inner and outer surfaces of the upper sub 10, which are generally perpendicular to the axis of the upper sub. In other words, the bore of the upper sub 10 has a first inner diameter toward the upper axial end, and a second wider inner diameter toward the lower axial end. Also in this example the lower axial end of the upper sub 10 comprises an axial end face 12 having chamfered edges.

The end face 12 is optionally generally perpendicular to the axis of the bore of the upper sub. Seals 18a, 18b are disposed in respective recesses of the inner counterbored portion and the outer reduced diameter portion, adjacent to the axial end face 12. Optionally an annular threaded locking ring 19 is provided on the reduced diameter portion of the outer surface, adjacent to the outer shoulder 15, for joining the flow diverter valve 1 to a tubular string, such as production tubing, above the flow diverter valve.

Also in this example, the upper and lower axial ends of the bore of the housing 20 are counterbored, to provide enlarged bore portions at both axial ends of the housing. The enlarged bore portions form upper and lower shoulders 24, 25 on the inner surface of the housing 20, which are generally perpendicular to the axis of the housing. In other words, the housing 20 has a first inner diameter in a central portion 22 of the housing 20, and a second wider inner diameter at the distal axial ends of the housing. The housing 20 further comprises a plurality of radial apertures or ports 23 disposed through the wall of the central portion 22 of the housing. The ports 23 extend between the bore of the housing and an outer surface of the housing. In this example, there are six ports 23 arranged circumferentially and equidistantly around the outer surface of the housing, but in other examples there may be fewer or more than six ports, and the ports need not be arranged circumferentially, regularly, symmetrically or equidistantly. Seals 26a, 26b and 28a, 28b are disposed in respective recesses in the inner surface of the central portion 22. Seals 26a, 26b are arranged adjacent to, and axially positioned above and below the ports 23 through the bore of the housing, and seals 28a, 28b are slightly axially spaced from each other and both positioned adjacent to the upper shoulder 24 of the housing 20.

In this example the bore of lower sub 30 has a generally constant inner diameter outside of a counterbored portion which extends a short distance into the upper axial end of the bore, and which provides an enlarged bore portion at the upper axial end of the lower sub. The corresponding outer surface of the lower sub 30 comprises a reduced diameter portion. The reduced diameter portion forms an outer shoulder 35 on the outer surface of the lower sub 30, which is generally perpendicular to the axis of the lower sub. Also in this example the inner surface of the counterbored portion of the bore comprises a circumferential bevelled seat 34 and a circumferential shoulder 32 which is chamfered. The inner surface of the counterbored portion between the bevelled seat 34 and the chamfered inner edge of the shoulder 32 comprises an axial surface 36 with parallel sides. In this example the lower axial end of the bore of the lower sub 30 is also counterbored and threaded, in a similar way to the upper axial end of the upper sub 10, to allow the flow diverter valve 1 to be optionally connected directly to the upper end of an ESP system. Optionally an annular threaded locking ring 39 is provided on the reduced diameter portion of the outer surface, adjacent to the outer shoulder 35, for joining the flow diverter valve 1 to an ESP system below the flow diverter valve.

The shuttle 50 in this example comprises a cylindrical sleeve having a bore 50b with an axis. The lower axial end of the shuttle 50 comprises a nose 54, which has a reduced outer diameter relative to a body 52 of the shuttle 50. In this example, the shuttle has a two-piece construction and the body 52 and nose 54 are formed separately and connected by e.g. a screw thread and optionally sealed, but the shuttle 50 could be formed differently in other examples, for example as a single piece, or as more than two pieces. The transition between the body 52 and nose 54 of the shuttle comprises an inwardly tapered surface in the form of a flange 58a (see Figs 3c,d) on the outer surface of the nose 54 as it protrudes from the threaded bore of the body 52; the flange 58a is oriented downward away from the body 52. The lower axial end of the nose 54 comprises a nose cap 56, which occludes the lower axial end of the bore 50b of the shuttle 50. In this example the nose cap 56 is conical and extends axially downward away from the end of the nose 54 of the shuttle, but in other examples the nose cap 56 may be shaped differently, and in some examples may be a flat disc disposed perpendicularly to the axis of the bore of the shuttle. A radially outer portion of the nose cap 56 comprises a sealing face 58b. Flange 58a axially approaches but typically does not contact shoulder 32 (e.g. flange 58a is slightly axially spaced from shoulder 32) when the shuttle 50 is in the first (lower) position. However, transitional contact between the nose cap 56 of the shuttle and shoulder 32 as the shuttle approaches the first (lower) position can allow for correction of any minor radial deviation or misalignment of the axis of the shuttle 50 from the axis of the bore lb. In other words, the shoulder 32 can guide the nose cap 56 (and therefore the shuttle 70) such that the axis of the shuttle is substantially coaxial with the axis of the bore lb as the nose cap axially approaches the surface 36 set in the inner surface of the lower sub 30. Sealing face 58b seats against bevelled seat 34 set in the inner surface of the lower sub 30 when the shuttle 50 is in the first (lower) position within the bore lb. The shuttle 50 in this example also comprises two arrays of radial apertures or ports 53, 55 which extend between the bore of the shuttle and an outer surface of the shuttle, and which permit fluid communication between the bore of the shuttle and the outside of the shuttle. The first array of ports 53, best seen in Figure 5a, is disposed in the body 52 of the shuttle 50 (above the nose 54), and is axially spaced from the second array of ports 55 disposed in the nose 54 of the shuttle between the flange 58a and sealing face 58b. In this example there are six body ports 53 and four nose ports 55, with both arrays of ports circumferentially and equidistantly spaced around the outer surface of the shuttle 50, but in other examples there may be fewer or more than six body ports 53 and four nose ports 55, and the ports need not be arranged circumferentially, nor spaced equidistantly, symmetrically or regularly.

The shuttle 50 further comprises a collar 60, shown in Figures 5a and 5b, which extends radially from the outer surface of the body 52 of the shuttle. In this example the collar 60 is annular and surrounds the body 52 of the shuttle, but in other examples the collar may not surround the body. The collar 60 comprises first and second end walls 62a, 62b and a circumferential rim 63. As best seen in Figure 5b, in this example the rim 63 of the collar 60 comprises four arcuate portions 66 and four flattened portions 67. The four flattened portions 67 are optionally formed by removing (e.g. cutting or milling) some material from the outer diameter of the rim 63 of the collar 60. The outer diameter of the collar 60 between symmetrically opposed flattened portions 67 is therefore less than the outer diameter of the collar between symmetrically opposed arcuate portions 66When the shuttle 50 is installed in the bore of the housing 20, the arcuate portions 66 of the rim 63 contact the inner surface of the housing 20 in a sliding fit (as best seen in Figures 4a and 4b), while the flattened portions 67 are radially displaced from the inner surface of the housing (as best seen in Figures 5c and 5d) to form gaps. The gaps which remain between the flattened portions 67 of the rim and the inner surface of the housing 20 form a fluid conduit which allows fluid to pass from one axial side of the collar 60 to the other.

The flow diverter valve 1 may be assembled according to the following steps. The upper axial end of the lower sub 30 is first received into the lower axial end of the bore of the housing 20, such that the bore of the lower sub is coaxial with the bore of the housing. The outer diameter of the reduced diameter portion of the lower sub 30 is a sliding fit within the inner diameter of the lower counterbored portion of the housing 20. Therefore, the lower sub 30 can be moved (i.e. pushed, optionally rotated on a screw thread) into the bore of the housing 20 until the upper axial end of the lower sub lands on the lower shoulder 25 of the housing 20. The lower axial end of the housing 20 is then adjacent to the threaded locking ring 39 on the outer surface of the lower sub 30. The threaded locking ring 39 can then be tightened to make up the connection between the lower sub 30 and the housing 20.

A magnetic ring 40, shown in Figure 2, is then inserted into the upper axial end of the housing 20, and moved (i.e. pushed) into the bore of the housing until the magnetic ring lands on the upper shoulder 24 of the housing. In this example the magnetic ring 40 is annular and comprises a plurality of discrete rare earth magnets 42a, 42b arranged in a regular pattern, e.g. equidistantly, around a radially-aligned surface of the magnetic ring. Also in the example, the polarity of each magnet is the reverse of the polarity of at least one and optionally both adjacent magnets. In other words, magnets 42a having an exposed North pole are alternately interspersed with magnets 42b having an exposed South pole. Optionally the magnetic ring 40 can be fixed to the housing 20 adjacent to the upper shoulder 24 via a screw thread, optionally to prevent subsequent axial movement of the magnetic ring relative to the housing. Furthermore, in this example, the magnets 42a, 42b are arranged on the surface of the magnetic ring to ensure that the magnets are radially aligned with both the arcuate portions 66 and flattened portions 67 of the collar 60. In other words, the diameter of the ring of magnets 42a, 42b seen in Figure 2 is greater than the outer diameter of the shuttle 50, but less than the diameter of the collar 60 between symmetrically opposed flattened portions 67.

The shuttle 50 is then received into the upper axial end of the bore of the housing 20.

A spring 7 is first passed over the upper axial end of the shuttle 50, and moved (i.e. pushed) axially over the outer surface of the shuttle until a first axial end of the spring lands on the collar 60 of the shuttle. The nose 54 of the shuttle 50 is then moved (i.e. pushed) into the upper axial end of the housing 20, and the shuttle (and spring 7) are passed through the bore of the housing until the sealing face 58b of the shuttle lands on the bevelled seat 34 of the lower sub 30. The outer diameter of the body 52 of the shuttle 50 is a sliding fit within the inner diameter of the central portion 22 of the housing 20, and the outer diameter of the nose 54 of the shuttle is a sliding fit within the inner diameter of the counterbored portion of the lower sub 30, such that the shuttle makes a sliding fit within the bore of the housing. As the shuttle 50 is received in the bore of the housing 20, seals 26a, 26b and 28a, 28b disposed in recesses in the inner surface of the housing form respective seals against the outer surface of the shuttle.

Finally, the lower axial end of the upper sub 10 is received into the upper axial end of the bore of the housing 20, such that the bore of the upper sub is coaxial with the bore of the housing. The outer diameter of the reduced diameter portion of the upper sub 10 is a sliding fit with the inner diameter of the upper counterbored portion of the housing 20. Therefore, the upper sub 10 can be moved (i.e. pushed, optionally rotated on a screw thread) into the bore of the housing 20 until the upper axial end of the housing 20 is adjacent to the threaded locking ring 19 on the outer surface of the upper sub 10. The threaded locking ring 19 can then be tightened to make up the connection between the upper sub 10 and the housing 20. Seals 18a, 18b form seals between the outer surface of the shuttle 50 and the upper sub 10, and between the upper sub 10 and the housing 20, thus forming a sealed chamber 5 in the annulus between the shuttle and the housing.

In operation, the flow diverter valve 1 is typically deployed within the production casing of an oil or gas well. The upper axial end of the flow diverter valve 1 is typically connected to the lower end of a production tubing string above the flow diverter valve, and the lower axial end of the valve 1 is typically directly connected to one or more ESP units installed below the flow diverter valve 1, or may optionally be connected to one or more ESP units via a short length of intermediate tubing such as a pup joint.

When one or more ESP units below the flow diverter valve 1 are inactive (for example, to allow maintenance of equipment at the wellhead, or because the natural fluid pressure in the formation of the well is sufficient to provide an adequate flow rate of production fluids to the surface of the well, without assistance from the ESPs), the flow diverter valve is in the configuration shown in Figure 3a. The spring 7 and magnetic ring 40 both exert a downward force on the collar 60 of the shuttle 50. As shown in Figure 4a, in this configuration, the spring 7 is uncompressed, and may be close to, or at, its maximum uncompressed axial length, and therefore the spring exerts relatively little downward force on the collar 60. In contrast, in this configuration the collar 60 has least axial distance from the magnetic ring 40, so the magnetic force attracting the collar toward the magnetic ring is higher than the force exerted by the spring and is optionally at a maximum.

Therefore, as seen in Figure 3a, the sealing face 58b of the shuttle 50 is in contact with, and urged against, the bevelled seat 34 set in the inner surface of the lower sub 30. The bore of the lower sub 30 (and also the outlet of the ESP below the fluid diverter valve) is thus isolated from the bore of the shuttle 50b, and the bore of upper sub 10 by the seated nose 54. Downward fluid flow through the bore 1b of the flow diverter valve 1 toward the ESP units is therefore prevented.

When the flow diverter valve 1 is in the configuration shown in Figure 3a, the body ports 53 of the shuttle 50 are axially aligned with the ports 23 of the housing 20. In this example, the shuttle 50 can optionally rotate relative to the housing 20, and there can be a slight annular gap between the outer surface of the shuttle and the inner surface of the housing in the region of the body ports 53 between seals 26a, 26b. This annular gap provides a flow path for fluid between the body ports 53 and the housing ports 23 in the event of rotational misalignment of the body ports with respect to the housing ports. Thus, radial fluid flow is permitted between the bore of the shuttle (and the bore of the upper sub 10) and the annulus between the fluid diverter valve 1 and the production casing of the well. Fluid flow through the ports 53 and 23 can be in either direction. When the fluid pressure in the annulus (e.g. the natural formation fluid pressure) is greater than the static head of fluid in the production tubing above the fluid diverter valve, fluid can flow from the annulus, through the aligned ports 53 and 23, and into the bore of the upper sub 10 and production tubing and toward the surface. Conversely, if the static head of fluid in the production tubing is greater than the pressure in the annulus, fluid can flow from the bore of the upper sub 10, through the aligned ports 53 and 23, and out into the annulus.

Normally the ESP units below the valve 1 are inactive when the wellbore pressure is sufficient to produce fluids under natural pressure from the well, and flow of the production fluids is normally in the upward direction, from the reservoir, through the annulus, through the aligned ports 53, 23 and into the production tubing above the valve 1, optionally bypassing the inactive ESP units entirely.

When the wellbore pressure within the reservoir decreases to a level insufficient to flow the production fluids from the well naturally, one or more ESP units below the flow diverter valve 1 are activated to lift the production fluids into the production tubing above the valve 1. As the ESP unit(s) are activated, fluid pressure will increase in the bore of the lower sub 30 below the nose 54 of the shuttle 50. When the upward force on the nose 54 of the shuttle caused by the increasing pressure in the bore of the lower sub 30 exceeds the combined downward force of the spring 7 and magnetic ring 40, the shuttle begins to slide axially toward the upper end of the flow diverter valve, toward the position seen in Figures 3b, 3c and 3d. As the shuttle 50 begins to slide axially from its initial position shown in Figure 3a, the seal between sealing face 58b of the shuttle and bevelled seat 34 of the lower sub is released. In this example the radially outermost edge of the nose cap 56 of the shuttle is very slightly radially separated from axial surface 36, for example by an approximately 0.025 mm gap.. Therefore, fluid flow is restricted, but not prevented, through the bore of the lower sub 30 to the bore of the shuttle 50b until the nose cap 56 is axially spaced from the surface 36, as seen in Figures 3b, 3c and 3d. Permitting only residual fluid flow between surface 36 and the radially outermost edge of the nose cap 56 as the shuttle 50 approaches the second (upper) position causes pressure to build in the bore of the lower sub 30 below the nose cap 56, in turn causing upward axial thrust on the shuttle 50. Also as the shuttle 50 begins to slide axially, the body ports 53 of the shuttle 50 begin to slide axially out of alignment with the ports 23 in the housing 20, and move above the upper seal 26a between the housing and the shuttle, so that the bore of the shuttle 50b is sealed from the ports 23 and the annulus outside the fluid diverter valve 1. In this example the axial dimension of the ports 53 is less than the axial length of the surface 36 of the lower sub 30, and so the ports 53, 23 have moved substantially out of alignment (i.e. the flow path through the ports 53, 23 is closed) before the nose cap 56 is axially spaced from the surface 36.

As the shuttle 50 begins to slide up from its initial position, the collar 60 of the shuttle 50 begins to move away from the magnetic ring 40. Since the magnetic force exerted on the collar 60 by the magnetic ring 40 is inversely proportional to the square of the distance (i.e. axial displacement) between the collar and the magnetic ring, the magnetic force on the collar decreases exponentially with increasing distance from the magnetic ring. Conversely, as the axial separation between the collar 60 and the axial end face 12 of the upper sub 10 decreases, the spring 7 is compressed between the collar 60 and axial end face 12. Since the force exerted on the collar 60 by the spring 7 is inversely proportional to the distance between the collar 60 and the axial end face 12, the spring force on the collar 60 increases (optionally linearly) with decreasing distance to the axial end face 12.

As the shuttle 50 slides toward the upper axial end of the flow diverter valve 1, the collar 60 moves axially through sealed chamber 5. As the collar 60 moves away from the magnetic ring 40 toward the axial end face 12 of the upper sub 10, a first cavity 6a in the sealed chamber 5 between the collar 60 and the axial end face 12 (which surrounds the spring 7) decreases in volume, while a second cavity 6b between the collar and the magnetic ring 40 increases in volume, best seen by comparing Figures 4a and 4b. In this example, the initial volume of the second cavity 6b can approach zero, because the collar 60 can initially be in contact with the magnetic ring 40. As the collar 60 moves axially through the sealed chamber, fluid in the first cavity 6a (which may optionally be a liquid or a gas) is permitted to flow into the second cavity 6b, as best seen in Figure 5c. In this example fluid is permitted to flow across the collar 60 through the radial gaps between the flattened portions 67 and the inner surface of the housing 20, but in other examples fluid may pass the collar 60 from the first cavity 6a to the second cavity 6b by other means, for example through apertures or ports or other bypass channels through the collar 60 e.g. between the radial faces 62a, 62b of the collar. Allowing fluid to pass freely from the first cavity 6a to the second cavity 6b prevents or substantially reduces the formation of positive and negative hydraulic locks in the first and second cavities of the sealed chamber 5 that would otherwise prevent or impede the sliding movement of the shuttle 50.

When the shuttle 50 has reached the position shown in Figure 3c, radial fluid flow between the annulus and the bore of the shuttle 50 through housing ports 23 is substantially prevented. The shuttle body ports 53 are no longer axially aligned with the housing ports 23, and are axially separated by seal 28a disposed between the housing 20 and shuttle 50, which therefore forms a seal between the body ports and the housing ports. However, axial fluid flow between the bore of the lower sub 30 and the bore 50b of the shuttle 50 is permitted through shuttle nose ports 55. Therefore, fluid flow generated by one or more ESP units below the flow diverter valve 1 may pass through the bore of the shuttle from the bore of the lower sub 30 to the bore of the upper sub 10 (i.e. through the length of the bore lb of the fluid diverter valve) and into the production tubing above the fluid diverter valve and on to the surface of the well. Fluid flow from the active ESP units passing the nose cap 56 of the shuttle continues to generate an upward force on the shuttle. The axial position of the shuttle within the bore of the fluid diverter valve 1 is maintained in the second position shown in Figure 3c as long as the upward force of fluid flow exceeds the downward force of the spring 7 on the collar 60 of the shuttle.

When the ESP units are deactivated, upward fluid flow through the bore lb passing the nose cap 56 of the shuttle 50 begins to reduce. As the corresponding upward force generated on the shuttle reduces, it is exceeded by the downward force of the spring 7 on the collar 60 of the shuttle, and the shuttle 50 begins to slide toward its first position, shown in Figure 3e. The collar 60 also begins to move in an axially downward direction through sealed chamber 5. The first cavity 6a in the sealed chamber 5 therefore decreases in volume, while the second cavity 6b increases in volume. As the collar 60 moves through the sealed chamber, fluid in the second cavity 6b is permitted to flow into the first cavity 6a, as best seen in Figure 5d, through the radial gaps between the flattened portions 67 of the collar 60 and the inner surface of the housing 20.

When the fluid flow through the bore lb toward the surface stops, the fluid remaining in the production tubing above the flow diverter valve may expose the fluid in the bore lb to a significant static head, which will cause the fluid flow through the bore lb to reverse and flow toward the one or more ESP units below the flow diverter valve. Downward fluid flow passing the nose cap 56 of the shuttle generates a downward force on the shuttle 50 to complement the downward force of the spring 7 on the shuttle, which urges the shuttle more strongly toward the first position, until the collar 60 approaches the magnetic ring 40, which then rapidly urges the shuttle into the first position. When the shuttle has reached the first position, sealing face 58b of the shuttle lands on, and is urged against, the bevelled seat 34, re-forming the seal against the inner surface of the lower sub 30 and preventing any further (reversed) axial fluid flow through the shuttle toward the ESP units below. This is advantageous as reverse fluid flow through an ESP can cause damage to the pump components.

Additionally, as the shuttle 50 approaches the first position seen in Figure 3e, the ports 23, 53 also axially re-align with each other, permitting radial fluid flow from the bore of the shuttle, and allowing fluid remaining in the production tubing above the flow diverter valve to drain through the bore of the shuttle and into the annulus outside the flow diverter valve without passing through the shuttle nose 54. The advantage of this is that any solids or debris present in the production fluid which remains in the production tubing above the flow diverter valve is flushed into the annulus outside the valve, instead of flowing down through the bore of the lower sub 30 and into the ESP units below. This reduces wear and can extend the operational lifetime of the ESP units, as any solids or debris that flow into the ESP unit can clog or also otherwise damage components of the pump.

The shuttle 50 further optionally comprises a reduced inner diameter portion 57 which incorporates an optional closure device disposed in the bore of the reduced inner diameter portion. In this example the closure device optionally takes the form of a flapper 59. The flapper 59 is pivotally mounted on the inner surface of the bore of the shuttle 50b to move between a closed position shown in Figures 3a, 3b, 3d and 3e, and an open position shown in Figure 3c. In this example the flapper 59 opens and closes the bore 50b of the shuttle 50, and is biased with a torsion spring (not shown in the Figures) toward the closed position. In this example the flapper 59 is disposed axially intermediate the body ports 53 and the nose 54 of the shuttle 50, and advantageously the flapper is disposed axially adjacent to and optionally immediately below the body ports 53 of the shuttle, for reasons that will be explained below. When the flapper 59 is closed, the bore of the nose 54 of the shuttle between the flapper and the flange 58a is isolated from the bore of the body 52.

When one or more ESPs below the flow diverter valve 1 incorporating flapper 59 are activated, fluid pressure will increase in the bore of the lower sub 30 below the nose 54 of the shuttle 50. When the increasing pressure has generated sufficient upward force on the nose 54 to start sliding the shuttle 50 axially toward the upper end of the flow diverter, as shown in Figure 3b, the seal between sealing face 58b of the shuttle and bevelled seat 34 of the lower sub is released. Fluid flow between the radially outermost edge of the nose cap 56 of the shuttle and axial surface 36 is restricted, but not prevented, until the body ports 53 of the shuttle slide axially out of alignment with the ports 23 in the housing 20. Therefore, in this example the flapper 59 is not exposed to significant fluid flow from the activated ESP until the bore 50b of the shuttle is isolated from the annulus between the fluid diverter valve 1 and the production casing of the well. In other words, in this example, the flapper 59 remains in a substantially closed position until the radially outermost edge of the nose cap 56 of the shuttle is axially spaced from the surface 36 of the lower sub. When the outermost edge of the nose cap 56 is axially spaced from the surface 36, unrestricted fluid flow past the flapper 59 overcomes the biasing force of the torsion spring of the flapper, and the flapper fully opens, as shown in Figure 3c. Fluid may then flow from the bore of the lower sub 30, through the bore of the shuttle 50b, and through the production tubing string above the flow diverter valve 1. As long there is sufficient fluid flow from the active ESP units passing the nose cap 56 and flapper 59, the flapper 59 will remain in its open position, and the shuttle 50 will remain in its second position as shown in Figure 3c.

When the ESP units are deactivated and fluid flow passing the nose cap 56 and flapper 59 begins to reduce, the torsion spring starts to bias the flapper toward its closed position, and the spring 7 starts to urge the shuttle 50 toward its first position.

In this example the torsion spring is relatively weaker than the spring 7.Optionally the closure device (e.g. flapper 59) moves into its closed position while the shuttle 50 is approaching the first position, optionally before the body ports 53 of the shuttle have started to align with the housing ports 23.

Additionally, when the fluid flow through the bore 1b toward the surface stops, the fluid remaining in the production tubing above the flow diverter valve may expose the fluid in the bore lb to a significant static head, which will cause the fluid flow through the bore to reverse and flow toward the one or more ESP units below the flow diverter valve. Fluid flow through the bore 50b of the shuttle 50 toward the lower sub will also urge the flapper 59 toward its closed position, and cause the flapper to close more rapidly than it might if only biased by the torsion spring. Rapid closure of the flapper 59, as seen in Figures 3c and 3d, can be advantageous for two reasons.

Firstly, the closed flapper occludes the bore 50b of the shuttle 50, so any static head due to fluid in the production tubing above the flow diverter valve 1 will strongly urge the shuttle 50 toward its first position, thus complementing (and possibly greatly exceeding) the downward force exerted on the shuttle 50 by the spring 7 and magnetic ring 40.

Secondly, as indicated previously, the flapper 59 is disposed below and axially adjacent to the body ports 53 of the shuttle 50. When the ESP units below the flow diverter valve 1 are deactivated, the flapper 59 moves toward its closed position as the upward fluid flow through the bore 50b of the shuttle 50 begins to diminish, optionally as the shuttle is approaching the first position shown in Figure 3e, and optionally as or immediately after the direction of movement of the shuttle changes to move toward the first position from the second position. Any solids or debris that sink down through the production fluid toward the nose 54 of the shuttle when the flow of production fluid slows and eventually becomes stationary are thus prevented by the flapper 59 from entering the nose of the shuttle, where they might reduce or block the flow area of the nose ports 55, or prevent the formation of fluid-tight seals between the sealing surface 58b of the shuttle and the inner surface of the lower sub 30. Debris is also blocked in this way from entering the ESP below the valve 1 from the bore of the shuttle 50.

Additionally, any debris which settles on the closed flapper 59 will be flushed out of the shuttle 50 through the ports 23, 53 and into the annulus outside the flow diverter valve 1 as the shuttle 50 moves into the first position. When the housing ports 23 and body ports 53 start to come into alignment, there can be an initial period of rapid fluid acceleration as the flow path area through the ports 23, 53 opens and increases in size. The rapid increase in flow rate through the ports 23, 53 causes turbulence in the bore 50b of the shuttle 50 above the flapper 59, which agitates and suspends any solids or debris settled on or near the flapper 59 into the production fluid which then flows out of the aligned ports 23, 53, bypassing the ESP system below the valve 1. This prevents any significant accumulation of solids or debris building up on the upper surface of the flapper as production fluid present in the bore 1 b of the flow diverter valve and in the production tubing above the valve drains into the annulus, thereby ensuring that the flapper 59 is not blocked or impeded from moving toward the open position to open the flow path through the bore 1 b of the valve 1 when the ESP units are next activated, and reducing the accumulation of debris in the ESP system via the shuttle 50.

Claims

Claims: 1. A flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system; and a shuttle slidable axially within the bore of the body between first and second positions; wherein in the first position, the shuttle engages a seat in the bore to restrict the bore flowpath and diverts fluid flow through a bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, and wherein the valve incorporates a fluid conduit to permit fluid flow across the collar between the first and second cavities.
2. A flow diverter valve as claimed in claim 1, wherein the fluid conduit permits fluid flow from the first cavity to the second cavity when the shuttle moves in a first axial direction relative to the body, and wherein the fluid conduit permits fluid flow from the second cavity to the first cavity when the shuttle moves in an opposing second axial direction relative to the body.
3. A flow diverter valve as claimed in claim 1 or claim 2, wherein the fluid conduit allows the pressure in the first cavity to remain approximately equal to the pressure in the second cavity, and prevents a significant pressure differential across the collar of the shuttle as the shuttle is moving between the first and second positions.
4. A flow diverter valve as claimed in any preceding claim, wherein the fluid flow between the first and second cavities is evenly distributed around the axis of the bore of the body.
5. A flow diverter valve as claimed in any preceding claim, wherein a first portion of the collar makes a sliding fit with a radially inner surface of the body, and a second portion of the collar makes a clearance fit with the inner surface of the body.
6. A flow diverter valve as claimed in any preceding claim, wherein the collar comprises at least one aperture to permit fluid flow between the first and second cavities.
7. A flow diverter valve as claimed in any preceding claim, wherein a first portion of a rim of the collar is matched to the inner surface of the body, and a second portion of the rim is radially spaced from the inner surface of the body.
8. A flow diverter valve as claimed in any preceding claim, wherein the surface area of first and second opposing end walls of the collar is less than the area of the annulus between the shuttle and the body.
9. A flow diverter valve as claimed in any preceding claim, wherein the first biasing device urges the shuttle toward the first position when the shuttle is in any axial position, and wherein the second biasing device urges the shuttle toward the first position when the shuttle is in the first position and as the shuttle approaches the first position.
10. A flow diverter valve as claimed in any preceding claim, wherein the first biasing device exerts a compressive force on the shuttle, and the second biasing device exerts a tensile force on the shuttle.
11. A flow diverter valve as claimed in claim 10, wherein the force exerted by the first biasing device decreases, and the force exerted by the second biasing device increases, as the shuttle approaches the first position.
12. A flow diverter valve as claimed in claim 10 or claim 11, where the maximum force exerted by the first biasing device on the shuttle in the second position is greater than the maximum force exerted by the second biasing device on the shuttle in the first position.
13. A flow diverter valve as claimed in any preceding claim, wherein the first biasing device comprises a resilient member, and wherein the second biasing device comprises a magnetic device adapted to exert a magnetic force on the shuttle.
14. A flow diverter valve as claimed in claim 13, wherein the magnetic device comprises a plurality of magnetic elements arranged circumferentially and spaced regularly around the axis of the body.
15. A flow diverter valve as claimed in claim 14, wherein the magnetic elements are arranged such that adjacent magnetic elements have opposing magnetic polarity.
16. A flow diverter valve as claimed in any preceding claim, wherein the shuttle is adapted to slide from the first position toward the second position when the pressure in the second portion of the bore is greater than the pressure in the first portion of the bore, and the pressure differential between the first and second portions of the bore is greater than a threshold pressure differential.
17. A flow diverter valve as claimed in claim 16, wherein the pressure differential threshold corresponds to a force sufficient to overcome the combined biasing force of both the first and second biasing devices when the shuttle is in the first position.
18. A flow diverter valve as claimed in any preceding claim, wherein the shuttle is maintained in the second position by fluid flow from the second portion of the bore to the first portion of the bore.
19. A flow diverter valve as claimed in any preceding claim, wherein the shuttle comprises a closure device disposed within the bore of the shuttle, wherein the closure device urges the shuttle toward the first position when the closure device is in a closed position.
20. A flow diverter valve as claimed in claim 19, wherein the closure device occludes the bore of the shuttle when in the closed position and causes fluid above the flow diverter valve to exert a force on the shuttle in the same direction as the biasing force of the first and second biasing devices.
21. A flow diverter valve as claimed in claim 19 or claim 20, wherein the force exerted on the shuttle by the closure device in the closed position is due to gravity acting on fluid in the bore of the body and in the ESP tubular string above the flow diverter valve.
22. A flow diverter valve as claimed in any one of claims 19 to 21, wherein the shuttle comprises one or more fluid ports adapted to axially align with the with the one or more fluid ports of the body when the shuttle is in the first position, and wherein the closure device is positioned below and axially adjacent to the shuttle flow ports.
23. A flow diverter valve as claimed in any one of claims 19 to 22, wherein debris present in fluid in the bore of the shuttle is flushed out of the one or more fluid ports of the shuttle, and does not accumulate in the bore of the shuttle.
24. A flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system; a shuttle slidable axially within the bore of the body between first and second positions; and a closure device disposed within a bore of the shuttle; wherein in the first position, the shuttle engages a seat in the bore of the body to restrict the bore flowpath and diverts fluid flow through the bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein a first portion of the collar makes a sliding fit with an inner surface of the body and a second portion of the collar makes a clearance fit with the inner surface of the body, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, wherein the closure device is adapted to move between a first position in which fluid flow through the bore of the shuttle is substantially prevented, and a second position in which fluid flow through the bore of the shuttle is permitted, and wherein the second portion of the collar permits fluid flow across the collar between the first and second cavities.
25. A flow diverter valve for use with an electric submersible pump (ESP) system deployed in an oil or gas well, the flow diverter valve comprising: a body with a bore having an axis, wherein the body comprises at least one radial port extending through a side wall of the body and connecting the bore to an outer surface of the body, the body having end connectors adapted to connect to a tubular string in the ESP system a shuttle slidable axially within the bore of the body between first and second positions; and a closure device disposed within a bore of the shuttle; wherein in the first position, the shuttle engages a seat in the bore of the body to restrict the bore flowpath and diverts fluid flow through the bore of the shuttle between the radial port and a first portion of the bore above the seat, and wherein in the second position, the shuttle closes the radial flowpath, is disengaged from the seat in the body to open the bore flowpath, and diverts fluid flow through the bore of the shuttle between a second portion of the bore below the seat and the first portion of the bore, wherein a collar of the shuttle extends into a sealed chamber disposed within an annulus between the shuttle and the body, and divides the sealed chamber into first and second cavities, wherein the valve incorporates first and second biasing devices acting on the collar of the shuttle and adapted to urge the shuttle toward the first position, wherein the first biasing device comprises a resilient member and the second biasing device comprises a magnetic device, wherein the closure device is adapted to move between a first position in which fluid flow through the bore of the shuttle is substantially prevented, and a second position in which fluid flow through the bore of the shuttle is permitted, wherein the closure device incorporates a third biasing device adapted to urge the closure device toward the first position, wherein the third biasing device is relatively stronger than the first biasing device, and wherein the valve incorporates a fluid conduit to permit fluid flow across the collar between the first and second cavities.