Apparatus for remote control of wellbore fluid flow

An apparatus for remotely controlling fluids in a well is provided. The flow control apparatus may include a body member having a flow port in an outer wall of the body member, and a flow aperture spaced inwardly from the outer wall. A remotely shiftable valve member may be disposed for reciprocal movement within the body member to regulate fluid flow through the flow aperture and flow port. An indexing sleeve may be rotatably disposed within the body member and engaged with the shiftable valve member to shift the valve member within the body member. An operating piston may be engaged with the indexing sleeve and movably disposed within the body member in response to pressurized fluid. A locking mechanism may also be included for locking the shiftable valve member in a closed, or sealing, position. Electrically-operated mechanisms for shifting the valve member is also provided.

BACKGROUND OF THE INVENTION
 1. Field of Invention
 The present invention relates to subsurface well completion equipment and,
 more particularly, to an apparatus and related methods for remotely
 controlling fluid recovery from a wellbore and/or any lateral wellbores
 extending therefrom.
 2. Related Art
 The economic climate of the petroleum industry demands that oil companies
 continually improve their recovery systems to produce oil and gas more
 efficiently and economically from sources that are continually more
 difficult to exploit and without increasing the cost to the consumer. One
 successful technique currently employed is the drilling of horizontal,
 deviated, and multilateral wells, in which a number of deviated wells are
 drilled from a main borehole. In such wells, and in standard vertical
 wells, the well may pass through various hydrocarbon bearing zones or may
 extend through a single zone for a long distance. One manner to increase
 the production of the well, therefore, is to perforate the well in a
 number of different locations, either in the same hydrocarbon bearing zone
 or in different hydrocarbon bearing zones, and thereby increase the flow
 of hydrocarbons into the well.
 One problem associated with producing from a well in this manner relates to
 the control of the flow of fluids from the well and to the management of
 the reservoir. For example, in a well producing from a number of separate
 zones, or laterals in a multilateral well, in which one zone has a higher
 pressure than another zone, the higher pressure zone may produce into the
 lower pressure zone rather than to the surface. Similarly, in a horizontal
 well that extends through a single zone, perforations near the "heal" of
 the well--nearer the surface--may begin to produce water before those
 perforations near the "toe" of the well. The production of water near the
 heal reduces the overall production from the well. Likewise, gas coning
 may reduce the overall production from the well.
 A manner of alleviating this problem is to insert a production tubing into
 the well, isolate each of the perforations or laterals with packers, and
 control the flow of fluids into or through the tubing. However, typical
 flow control systems provide for either on or off flow control with no
 provision for throttling of the flow. To fully control the reservoir and
 flow as needed to alleviate the above described problem, the flow must be
 throttled. A number of devices have been developed or suggested to provide
 this throttling although each has certain drawbacks. Note that throttling
 may also be desired in wells having a single perforated production zone.
 Specifically, the prior devices are typically either wireline retrievable
 valves, such as those that are set within the side pocket of a mandrel, or
 tubing retrievable valves that are affixed to the tubing string. An
 example of a wireline retrievable valve is shown in U.S. patent
 application Ser. No. 08/912,150 by Ronald E. Pringle entitled Variable
 Orifice Gas Lift Valve for High Flow Rates with Detachable Power Source
 and Method of Using Same that was filed Aug. 15, 1997 and which is hereby
 incorporated herein by reference. The variable orifice valve shown in that
 application is selectively positionable in the offset bore of a side
 pocket mandrel and provides for variable flow control of fluids into the
 tubing. The wireline retrievable valve has the advantage of retrieval and
 repair while providing effective flow control into the tubing without
 restricting the production bore. However, one drawback associated with the
 current wireline retrievable-type valves is that the valves have somewhat
 limited flow area an important consideration in developing a flow control
 systems.
 A typical tubing retrievable valve is the standard "sliding sleeve" valve,
 although other types of valves such as ball valves, flapper valves, and
 the like may also be used. In a sliding sleeve valve, a sleeve having
 orifices radially therethrough is positioned in the tubing. The sleeve is
 movable between an open position, in which the sleeve orifices are aligned
 with orifices extending through the wall of the tubing to allow flow into
 the tubing, and a closed position, in which the orifices are not aligned
 and fluid cannot flow into the tubing. Elastomeric seals extending the
 full circumference of the sleeve and located at the top of the sleeve and
 the bottom of the sleeve provide the desired sealing between the sleeve
 and the tubing. Due to the presence of the elastomeric seals, reliability
 may be an issue if the sleeve valve is left downhole for a long period of
 time because of exposure to caustic fluids.
 Remote actuators for the sleeve valves have recently been developed to
 overcome certain other difficulties often encountered with operating the
 valves in horizontal wells, highly deviated wells, and subsea wells using
 slickline or coil tubing to actuate the valve. The remote actuators are
 positioned in the well proximal the valve to control the throttle position
 of the sleeve.
 However, after a sleeve valve has been exposed to a wellbore environment
 for some time, the sleeve may be stuck or rendered more difficult to
 operate due to corrosion and debris. Additionally, the hydraulic seals of
 the sleeve add substantial drag to movement of the sleeve valve, rendering
 its operation even more difficult. Sleeve valves may require relatively
 large forces to overcome the drag from hydraulic seals in the valve,
 particularly when the sleeve valve is exposed to high pressure and
 corrosion. In addition, a sleeve valve may require a relatively long
 stroke to move between a fully open position and a fully closed position.
 As a result of the relatively large forces and long strokes employed to
 actuate a sleeve valve, an actuator employed to open and close the valve
 may need to be relatively high powered. Providing such high power may
 require a large actuator, sophisticated electronic circuitry, and
 relatively large diameter electrical cables, run from the surface to the
 valve actuator mechanism.
 An additional problem associated with the use of hydraulic actuators is the
 limitations in the number of possible choke positions. Some prior systems,
 such as that shown in the U.S. patent application Ser. No. 09/037,309 by
 Ronald E. Pringle entitled Variable Orifice Gas Lift Valve for High Flow
 Rates with Detachable Power Source and Method of Using Same that was filed
 Mar. 3, 1998 and which is incorporated herein by reference, utilize a
 shifting system employing slots to selectively move the valve to a variety
 of predetermined choke positions between open and closed. Because the
 shifting system required for a hydraulic actuator limits the number of
 possible positions within which the choke may be placed, the ability to
 control the flow and pressure is limited. Thus, a system providing finer
 control of the flow through the choke is desired.
 Consequently, despite the features of the prior art, there remains a need
 for a flow control system that provides a relatively high flow rate, that
 reduces the power requirements for operation over previous designs, that
 is adaptable to the requirements of the particular well, that provides for
 finer control of the choke when using a hydraulic actuator, and that
 provides an efficient, reliable, erosion-resistant system that can
 withstand the caustic environment of a well bore.
 SUMMARY
 To achieve such improvements, the present invention provides an apparatus
 for remote control of wellbore fluid that includes at least one aperture
 extending through the wall of a tubing, a shiftable valve member
 positioned and adapted to selectively open, close, and choke the valve
 member, and an actuator attached to and adapted to selectively shift valve
 member. By providing a plurality of valve members and providing variations
 to the shift mechanism, the flow into (or from) the tubing may be
 controlled and the shifting mechanism can be designed to provide a high
 number of shifting positions.
 One aspect of the present invention provides an apparatus for remote
 control of wellbore fluid flow that includes a body member having at least
 one flow port in an outer wall of the body member and at least one flow
 aperture spaced from the outer wall. At least one remotely shiftable valve
 member is offset from an inner bore in the body member and disposed for
 reciprocal movement within the body member to regulate fluid flow through
 at least one flow aperture and through at least one flow port. An actuator
 is adapted to selectively shift at least one remotely shiftable valve
 member between the open and closed positions.
 In one preferred embodiment, the actuator includes an indexing sleeve
 rotatably disposed within the body member and engaged with the shiftable
 valve member to shift the shiftable valve member within the body member.
 The indexing sleeve is disposed for rotatable movement about an inner wall
 within the body member and secured to the inner wall to restrict
 longitudinal movement therebetween. The first end of the indexing sleeve
 includes a flange movably engaged with a recess in the second end of the
 shiftable valve member, the flange includes at least one protuberance
 engageable with the recess. Further, the indexing sleeve is rotatable into
 a plurality of discrete positions to remotely control the degree to which
 the shiftable valve member is opened and closed.
 In a preferred embodiment, the actuator includes an operating piston
 engaged with the indexing sleeve and movably disposed within the body
 member in response to pressurized fluid. The indexing sleeve includes an
 indexing profile having an alternating series of ramped slots disposed in
 a zig-zag pattern about the indexing sleeve. The operating piston includes
 an arm having a finger disposed at a distal end thereof and engaged with
 the indexing profile. Each ramped slot includes a first end and a second
 end and inclines upwardly from its first end to its second end. The first
 and second ends of neighboring slots are adjacent to one another and an
 intersection of each of the adjacent first and second ends are defined by
 a retaining shoulder. In a selected embodiment, the operating piston is
 sealably disposed for movement within an operating piston cylinder in the
 body member between the inner and outer walls. Preferably, a first side of
 the operating piston is in fluid communication with a source of
 pressurized fluid and a second side of the operating piston is biased in
 opposition to the source of pressurized fluid by at least one of a spring,
 a contained source of pressurized gas within the body, and a remote source
 of pressure. A lockdown sleeve is engaged with the indexing sleeve and at
 least one lockdown piston. A first end of the lockdown sleeve has a
 locking protuberance releasably engageable with a locking recess in the
 body member. A first end of the lockdown piston is connected to an annular
 locking member. The lockdown piston causes the annular locking member to
 force the shiftable valve member into a locked position when the locking
 protuberance is engaged with the locking recess. The lockdown piston
 includes an arm having a finger disposed at a second end of the lockdown
 piston, is engaged with an annular groove in the lockdown sleeve. The arm
 is in fluid communication with a source of pressurized fluid, has a
 diameter less than a diameter of the operating piston, and is sealably
 disposed for movement within a lockdown piston cylinder in the body
 member.
 In an alternative preferred embodiment, the actuator includes an electrical
 conduit connected to an electric motor. The electric motor is secured to
 the body member and mechanically engaged with the indexing sleeve. The
 electric motor includes a shaft having a pinion gear connected thereto.
 The pinion gear is adapted for engagement with a plurality of teeth
 disposed about the indexing sleeve.
 In another preferred embodiment, the actuator includes an electrical
 conduit connected to an electric motor. The electric motor is secured to
 the body member and mechanically engaged with the remotely shiftable valve
 member. The electric motor includes a shaft having a pinion gear connected
 thereto. The pinion gear is adapted for engagement with a ball and screw
 assembly. The ball is rotatably engaged with the pinion gear and the screw
 is connected to the shiftable valve member and threadably disposed within
 the ball.
 In another selected embodiment, the body member includes a first end, a
 second end, and an inner wall disposed within the body member, spaced from
 the outer wall, extending from the second end of the body member, and has
 a distal end terminating within the body member. The flow aperture and the
 shiftable valve member is disposed between the inner and outer walls.
 Another preferred embodiment includes a spring biasing the shiftable valve
 member toward the flow aperture. The remotely shiftable valve member is
 preferably sealably disposed for movement within a valve cylinder in the
 body member.
 Another preferred embodiment includes at least one secondary shiftable
 valve member for controlling fluid flow through a corresponding secondary
 flow aperture in the body member. The diameters of the secondary shiftable
 valve member and the secondary flow aperture are less than the respective
 diameters of the shiftable valve member and the flow aperture.
 Another aspect of the present invention provides an apparatus for remote
 control of wellbore fluid flow that includes several parts. One part of
 the apparatus is a body member that has a first end, a second end, an
 outer wall, an inner wall, at least one flow port in the outer wall, and
 at least one flow aperture that is between the inner and outer walls. The
 inner wall is spaced from the outer wall, extends from the second end of
 the body member, and has a distal end terminating within the body member.
 The apparatus also includes at least one remotely shiftable valve member
 that is for reciprocal movement within the body member between the inner
 and outer walls. This valve regulates fluid flow through the flow aperture
 and through the flow port. Another part of the apparatus includes an
 indexing sleeve that rotates about the inner wall and is secured to the
 inner wall to restrict longitudinal movement therebetween. The indexing
 sleeve is engaged with the shiftable valve member to shift the shiftable
 valve member within the body member. And finally the apparatus has an
 operating piston engaged with the indexing sleeve, sealably disposed for
 movement within an operating piston cylinder in the body member between
 the inner and outer walls. A first side of the operating piston is in
 fluid communication with a source of pressurized fluid. A second side of
 the operating piston is biased in opposition to the source of pressurized
 fluid by at least one of a spring, a contained source of pressurized gas
 within the body member, and a remote source of pressure.
 In one preferred embodiment, a first end of the indexing sleeve includes a
 flange movably to engaged with a recess in a second end of the shiftable
 valve member. The flange includes at least one protuberance engageable
 with the recess. The indexing sleeve includes an indexing profile having
 an alternating series of ramped slots disposed in a zig-zag pattern about
 the indexing sleeve. The operating piston includes an arm having a finger
 disposed at a distal end that is engaged with the indexing profile. Each
 ramped slot includes a first end and a second end and inclines upwardly
 from its first end to its second end. The first and second ends of
 neighboring slots are disposed adjacent to one another and an intersection
 of each of the adjacent first and second ends are defined by a retaining
 shoulder. A lockdown sleeve is engaged with the indexing sleeve and with
 at least one lockdown piston. A first end of the lockdown sleeve has a
 locking protuberance releasably engageable with a locking recess in the
 body member. A first end of the lockdown piston is connected to an annular
 locking member. The lockdown piston causes the annular locking member to
 force the shiftable valve member into a locked position when the locking
 protuberance is engaged with the locking recess. To remotely control the
 degree to which the shiftable valve member is opened and closed, the
 indexing sleeve is rotatable into a plurality of discrete positions.
 Another aspect of the present invention provides an apparatus for remote
 control of wellbore fluid flow that comprises a body member that has at
 least one flow port in an outer wall of the body member and at least one
 flow aperture spaced from the outer wall. The apparatus also includes
 shiftable valve means for regulating fluid flow through the flow aperture
 and actuating means for selectively shifting the valve means between open
 and closed positions.
 In a preferred embodiment the actuating means includes rotatable indexing
 means engaged with the valve means for shifting the valve means, a piston
 means engaged with the indexing means for shifting the indexing means into
 a plurality of discrete positions, and means for remotely controlling
 movement of the piston means. In one alternative embodiment, the actuating
 means includes electrically-operated means connected to the body member
 and engaged with the valve means.

DETAILED DESCRIPTION OF THE INVENTION
 For the purposes of this discussion, the terms upper and lower, up hole and
 downhole, and upwardly and downwardly are relative terms to indicate
 position and direction of movement in easily recognized terms. Usually,
 these terms are relative to a line drawn from an upmost position at the
 surface to a point at the center of the earth, and would be appropriate
 for use in relatively straight, vertical wellbores. However, when the
 wellbore is highly deviated, such as from about 60 degrees from vertical,
 or horizontal these terms do not make sense and therefore should not be
 taken as limitations. These terms are only used for ease of understanding
 as an indication of what the position or movement would be if taken within
 a vertical wellbore.
 Referring now to the drawings in detail, wherein like numerals denote
 identical elements throughout the several views, it can be seen with
 reference to FIGS. 1A-1B that the flow control apparatus of the present
 invention is generally referred to by the numeral 10. The flow control
 apparatus 10 includes a body member 12 having a first end 14 (FIG. 1A), a
 second end 16 (FIG. 1B), an outer wall 18, and an inner wall 20 disposed
 within the body member 12 and spaced from the outer wall 18. The inner
 wall 20 extends from the second end 16 of the body member 12 and has a
 distal end 22 (FIG. 1A) terminating within the body member 12. In a
 specific embodiment, the distal end 22 may terminate between at least one
 flow port 24 in the outer wall 18 of the body member 12 and the first end
 14 of the body member 12. The inner wall 20 includes an inner bore 26 and
 an outer surface 28. The inner bore 26 extends from the distal end 22 to
 the second end 16 of the body member 12.
 With reference to FIG. 1A, the body member 12 further includes at least one
 flow aperture 30. In a specific embodiment, the at least one flow aperture
 30 may be disposed in the body member 12 between the outer wall 18 and the
 inner wall 20, and between the at least one flow port 24 and the first end
 14 of the body member 12. In a specific embodiment, the at least one flow
 aperture 30 may be disposed proximate the distal end 22 of the inner wall
 20. In a specific embodiment, the at least one flow aperture 30 may
 further include a first annular sealing surface 32. Still referring to
 FIG. 1A, the flow control apparatus 10 further includes at least one
 remotely shiftable valve member 34 offset from the inner bore 26 in the
 body member 12 and disposed for reciprocal movement within the body member
 12 to alternately permit and prevent fluid flow through the at least one
 flow aperture 30. The present invention is not limited to any particular
 number of valve members 34 although a preferred embodiment includes a
 plurality of valve members to provide a relatively high potential flow
 rate. Each valve member 34 may include a second annular sealing surface 36
 adjacent a first end 38 of the valve member 34 for cooperative sealing
 engagement with the first annular sealing surface 32 disposed about the at
 least one flow aperture 30. The valve member 34 is further provided with a
 recess 40 adjacent a second end 42 of the valve member 34, the purpose of
 which will be explained below. The valve member 34 may be biased toward
 the at least one flow aperture 30, and into a sealing position to prohibit
 fluid flow through the at least one flow aperture 30, by a spring 44
 disposed about the valve member 34, and between an annular shoulder 46 on
 the valve member 34 and a tubular insert 48 disposed between the outer
 wall 20 and the inner wall 18. The tubular insert 48 may be affixed to, or
 part of, the body member 12, and may include a valve cylinder 50 within
 which a cylindrical portion 35 of the valve member 34 may be sealably
 disposed for axial movement.
 The flow control apparatus 10 may further include an actuator adapted to
 selectively shift the at least one remotely shiftable valve member between
 open and closed positions. In a specific embodiment, as shown in FIGS. 1A
 and 4, the actuator may include an indexing sleeve 52 rotatably disposed
 within the body member 12 and engaged with the at least one shiftable
 valve member 34 to shift the at least one shiftable valve member 34 within
 the body member 12. In a specific embodiment, the indexing sleeve 52 may
 be rotatably disposed, as per bearings 54 and 56, about the outer surface
 28 of the inner wall 20. While the indexing sleeve 52 is rotatable
 relative to the body member 12, the valve 10 is adapted to restrict
 longitudinal movement between the indexing sleeve 52 and the body member
 12, as per a retaining ring 58 and an annular retaining shoulder 60, both
 of which may be disposed about the outer surface 28 of the inner wall 20.
 A first end 62 of the indexing sleeve 52 includes a flange 64 movably
 engaged with the recess 40 in the second end 42 of the shiftable valve
 member 34. As best shown in FIG. 4, the flange 64 includes at least one
 cam-like protuberance 66 extending away from the first end 62 of the
 indexing sleeve 52. In a specific embodiment, the protuberance 66 may have
 a semi-circular profile. As the indexing sleeve 52 rotates about the outer
 surface 28 of the inner wall 20, the flange 64 will move relative to the
 recess 40 in the at least one shiftable valve member 34. When only the
 flange 64 is engaged with the recess 40L, as shown with regard to the
 valve member 34L on the left side of FIG. 1A (hence the L designator), the
 second annular sealing surface 36L of the shiftable valve member 34L will
 be sealably engaged with the first annular sealing surface 32L so as to
 prohibit fluid flow through the at least one flow aperture 30L. But when
 the flange protuberance 66 moves into engagement with the recess 40, as
 shown with regard to the valve member 34 on the right side of FIG. 1A, the
 valve member 34 will be shifted, or pulled, away from the at least one
 flow aperture 30, thereby separating the first and second annular sealing
 surfaces 32 and 36 and permitting fluid flow through the at least one flow
 aperture 30. This will also establish fluid communication between a first
 bore 13 of the body member 12 and the at least one flow port 24 in the
 outer wall 18 of the body member 12.
 The indexing sleeve 52 is shown with only one protuberance 66 for clarity
 only. This should not be taken as a limitation. Instead, the flange 64 may
 be provided with any number of protuberances 66, depending upon on the
 number of shiftable valve members 34 and flow apertures 30 provided. In
 addition, the protuberance 66 may be provided with a height H1 variable up
 to approximately equal to a width W of the recess 40. By varying the
 height H1 of the protuberance 66, the degree to which the shiftable valve
 member 34 will be open when the protuberance 66 is engaged with the recess
 40 will also vary. The number and height H1 of the protuberances 66, as
 well as their respective locations along the flange 64, may be varied and
 provided in any number of combinations depending upon the number of
 shiftable valve members 34, and upon the degree to which it is desired to
 hold each valve member 34 open for a given position of the indexing sleeve
 52. Various manners in which the indexing sleeve 52 may be remotely
 rotated within the body member 12 will now be explained.
 As shown in FIGS. 1A-1B and 4, the indexing cylinder 52 includes an
 indexing profile 68 engaged with an operating piston 70 (FIG. 1B). In a
 specific embodiment, as shown in FIG. 4, the indexing profile 68 may
 include an alternating series of ramped slots 72 disposed in a zig-zag
 pattern about the indexing sleeve 52 and proximate a second end 63
 thereof. In a specific embodiment, each slot 72 may include a first end
 74, a second end 76, and a retaining shoulder 78. Each slot 72 inclines
 upwardly from its first end 74 to its second end 76. The first end 74 of
 any given slot 72 is disposed adjacent the second end 76 of its
 immediately neighboring slot 72. The intersection of each set of adjacent
 first and second ends 74 and 76 is defined by a corresponding retaining
 shoulder 78.
 As best shown in FIG. 1B, the operating piston 70 may include an arm 80
 having a finger 82 disposed at a distal end thereof and engaged with the
 indexing profile 68 in the indexing sleeve 52. The operating piston 70 may
 be sealably disposed for axial movement within a piston cylinder 84 formed
 in the body member 12. In a specific embodiment, the piston cylinder 84
 may be formed between the outer and inner walls 18 and 20. In a specific
 embodiment, a first surface 86 of the operating piston 70 may be in fluid
 communication with a source of pressurized fluid (not shown), which may be
 supplied through a hydraulic conduit 88 (see FIG. 1A). In a specific
 embodiment, the hydraulic conduit 88 may be connected between the body
 member 12 and the earth's surface (not shown). As indicated by the dashed
 line 90 in FIG. 1A, the hydraulic conduit 88 is in fluid communication
 with a sealed chamber 92 in the body member 12 and with the first surface
 86 of the operating piston 70 (see FIG. 1B).
 With reference to FIG. 1B, this specific embodiment of this aspect of the
 present invention may further include some means of exerting force on a
 second surface 87 of the operating piston 70. In a specific embodiment,
 this force may be supplied by a spring 94. In another specific embodiment,
 this force may by supplied by annulus pressure through a port 96 through
 the outer wall 18 of the body member 12. In another specific embodiment,
 this force may be supplied by another source of pressurized fluid (not
 shown) through another hydraulic conduit (not shown) connected to the port
 96. In another specific embodiment, the force may be supplied by
 pressurized gas, such as nitrogen, contained within a gas chamber 98 in
 the body member 12. In a specific embodiment, the pressurized gas may be
 contained within a gas conduit 100 coiled within an annular space 102 in
 the body member 12. In a specific embodiment, the port 96 may be a gas
 charging port, and may include a dill core valve (not shown), for charging
 the gas chamber 98 and/or gas conduit 100 with pressurized gas. The gas
 chamber 98 and/or gas conduit 100 may further include a lubricating
 barrier, such as silicone (not shown). The present invention is not
 intended to be limited to any particular means for biasing the operating
 piston 70 against the force of hydraulic fluid in the hydraulic conduit
 88. These specific embodiments (i.e., spring, annulus pressure, another
 hydraulic control line, and gas charge) are merely provided as examples,
 and may be used alone or in any combination.
 In operation, the piston finger 82 (see FIGS. 1B and 4) may be remotely
 moved within the indexing profile 68 in the indexing sleeve 52. If the
 force being applied to the first surface 86 of the operating piston 70 is
 greater than the force being applied to the second surface 87 of the
 operating piston 70, then the piston finger 82 will be biased downwardly
 against the first end 74 of one of the slots 72, as shown in FIG. 4. By
 the same token, if the force being applied to the first surface 86 of the
 operating piston 70 is less than the force being applied to the second
 surface 87 of the operating piston 70, then the piston finger 82 will be
 biased upwardly (not shown) against the first end 74 of one of the slots
 72. To shift the piston finger 82 from the position shown in FIG. 4 into a
 different position, pressure is removed from the hydraulic conduit 88
 until the force being applied to the second surface 87 of the operating
 piston 7015 (FIG. 1B) (e.g., by the spring 94, gas charge, additional
 hydraulic control line, and/or annulus pressure) is sufficient to force
 the piston finger 82 upwardly along the inclined surface of the slot 72
 until the piston finger 82 falls into the first end 74 of the immediately
 neighboring slot 72. If that pressure is maintained, the piston finger 82
 will remain in this position. If the pressure in the hydraulic conduit 88
 is increased above the upward force being applied to the second surface 87
 of the operating piston 70, then the piston finger 82 will travel
 downwardly against the retaining shoulder 78 and along the upwardly
 inclined surface of the neighboring slot 72 into which it was just
 shifted. The retaining shoulder 78 will prevent the piston finger 82 from
 going back into the slot 72 from which it just came. The piston finger 82
 will continue along the upwardly inclined surface until it falls into the
 next slot 72. By remotely moving the piston finger 82 within the indexing
 profile 68 in this manner, the indexing sleeve 52 is rotated into a
 plurality of discrete positions, thereby remotely controlling which of the
 shiftable valve members 34 are open and closed, depending on the number of
 protuberances 66 engaged with the recesses 40, and for those that are
 open, the extent to which they are opened. In this regard, movement of the
 piston finger 82 within the zig-zag indexing profile 68 will result in a
 separate discrete position of the indexing sleeve 52 for each position of
 the piston finger 82 in each of the first ends 74 of the slots 72. The
 number of discrete positions of the indexing sleeve 52 may be varied by
 varying the zig-zag profile 68, and may be designed to correspond to the
 number of shiftable valve members 34.
 The flow control apparatus 10 of the present invention may further be
 provided with a mechanism for locking the at least one shiftable valve
 member 34 in a fully-closed, or sealing, position. In this regard, with
 reference to FIGS. 1A and 4, the apparatus 10 may further include a
 lockdown sleeve 104 engaged with the indexing sleeve 52 and with at least
 one lockdown piston 106. In a specific embodiment, the lockdown sleeve 104
 may be disposed about the indexing sleeve 52, and, as best shown in FIG.
 4, may include at least one locking finger 108 engaged with a
 corresponding at least one locking slot 110 in the indexing sleeve 52. The
 engagement of the locking fingers 108 with the locking slots 110 prohibits
 relative rotational movement between the indexing sleeve 52 and the
 lockdown sleeve 104, but permits relative longitudinal movement between
 the two only when the indexing sleeve 52 and the lockdown sleeve 104 are
 in a particular discrete rotational position. Specifically, longitudinal
 relative movement between the indexing sleeve 52 and the lockdown sleeve
 104 will be permitted when a locking protuberance 112 extending from a
 first end 114 of the lockdown sleeve 104 is aligned with a locking recess
 116 disposed in a locking shoulder 118 extending from the outer wall 18 of
 the body member 12. The locking shoulder may include a first surface 128
 and a second surface 129. In a specific embodiment, the locking recess 116
 may be disposed in the second surface 129 of the locking shoulder 118.
 This aspect of the present invention will be more fully described
 momentarily.
 With reference to FIG. 1A, the at least one lockdown piston 106 may include
 a first end 107 connected to an annular locking member 119, as by threads.
 In a specific embodiment, the annular locking member 119 may be disposed
 between the outer and inner walls 18 and 20, and between the second ends
 42 of the shiftable valve members 34 and the first surface 128 of the
 locking shoulder 118. The lockdown piston 106 may further include an arm
 120 having a finger 122 disposed at a second end 109 of the lockdown
 piston 106 and engaged with an annular groove 124 in the lockdown sleeve
 104. In a specific embodiment, as shown in FIG. 1A, the at least one
 lockdown piston 106 may be sealably disposed for axial movement within a
 lockdown cylinder 126 in the body member 12, and be in fluid communication
 with pressurized fluid in the hydraulic conduit 88. In a specific
 embodiment, the lockdown cylinder 126 may be disposed in the locking
 shoulder 118. In a specific embodiment, the diameter of the lockdown
 piston cylinder 126 may be less than the diameter of the operating piston
 cylinder 84 (FIG. 1B).
 In operation, when pressurized fluid is being supplied from the hydraulic
 conduit 88 to the sealed chamber 92, the pressurized fluid will apply an
 upward force to the at least one lockdown piston 106 and a downward force
 to the operating piston 70. The upward force applied to the at least one
 lockdown piston 106 is translated to the lockdown sleeve 104 through the
 lockdown finger 122 on the lockdown piston 106 and the annular groove 124
 in the lockdown sleeve 104. As best shown in FIG. 4, so long as the
 locking protuberance 112 on the first end 114 of the lockdown sleeve 104
 is not aligned with the locking recess 116 in the body member 12, the
 first end 114 of the lockdown sleeve 104 and the second surface 129 of the
 lockdown shoulder 118 will be separated by a gap G, and no upward force
 will be applied through the annular locking member 119 to the at least one
 shiftable valve member 34. When the locking protuberance 112 is rotated
 into alignment with the locking recess 116, however, the at least one
 lockdown piston 106 will shift upwardly, carrying the locking protuberance
 112 into engagement with the locking recess 116 and forcing the annular
 locking member 119 against the second end 42 of the at least one shiftable
 valve member 34 to lock the at least one shiftable valve member 34 into
 its closed, or sealing, position. To unlock the at least one shiftable
 valve member 34, the indexing sleeve 52 is rotated into its next discrete
 position, in the manner explained above, thereby disengaging the locking
 protuberance 112 from the locking recess 116. It is noted that the locking
 recess 116 may include a ramped surface 117 to facilitate the
 disengagement of the locking protuberance 112 therefrom.
 With reference to FIG. 4, it is noted that the cam-like protuberance 66 on
 the flange 64 at the first end 62 of the indexing sleeve 52 are preferably
 not engaged with any of the recesses 40 of the shiftable valve members 34
 when the locking protuberance 112 on the first end 114 of the lockdown
 sleeve 104 is aligned with the locking recess 116 in the body member 12.
 It is further noted that the at least one locking finger 108 on the
 lockdown sleeve 104 has a height H2 larger than the gap G so that the at
 least one locking finger 108 will not become disengaged from the at least
 one locking slot 110 in the indexing sleeve 52 when the locking
 protuberance 112 shifts into engagement with the locking recess 116.
 Referring now to FIG. 5, it can be seen that, in addition to the shiftable
 valve members 34, the flow control apparatus 10 of the present invention
 may further include at least one secondary shiftable valve member 130 for
 controlling fluid flow through a secondary flow aperture 132 in the body
 member 12. The secondary valve member 130 and secondary flow aperture 132
 may include annular sealing surfaces as described above in relation to the
 valve member 34 and flow aperture 30. The structure and operation of the
 secondary valve member 130 is substantially the same as described above
 with regard to the valve member 34. In a specific embodiment, the
 diameters of the secondary valve member 130 and the secondary flow
 aperture 132 may be smaller than the respective diameters of the shiftable
 valve member 34 and flow aperture 30. In a specific embodiment, the
 secondary flow apertures 132 may be disposed in a portion of the body
 member 12 nearer the first end 14 of the body member 12 than the flow
 apertures 30.
 Another manner by which the indexing sleeve 52 may be remotely rotated will
 now be described with reference to FIGS. 7 and 8. In this specific
 embodiment, an electric motor 134 is secured to the body member 12' and
 connected to an electrical conduit 136 running from the earth's surface
 (not shown). The electric motor 134 is mechanically engaged with the
 indexing sleeve 52'. The electric motor 134 may include a shaft 138 having
 a pinion gear 140 connected thereto. As shown in FIG. 7, the pinion gear
 140 may be engaged with a plurality of teeth 142 disposed about the
 indexing sleeve 52'. When electrical energy is supplied to the motor 134,
 the pinion gear 140 will be rotated, which will cause the indexing sleeve
 52' to rotate. Operation of the apparatus 10' is as described above in all
 other respects.
 Another electrically-operated embodiment of the present invention is shown
 in FIG. 8. In this specific embodiment, the indexing sleeve 52 is omitted,
 and an electric motor 134' is engaged with one of the at least one
 shiftable valve members 34'. A ball and screw assembly 144 may be
 connected between the electric motor 134' and the valve member 34'. The
 electric motor 134' may be connected to the body member 12" and to an
 electrical conductor 136' in the same manner as described above. The
 electric motor 134' may also include a shaft 138' having a pinion gear
 140' connected thereto, in the same manner as described above. The pinion
 gear 140' may be engaged with the ball 146, which is threadably engaged
 with the screw 148. The screw 148 may be connected to or part of the valve
 member 34'. By energizing the motor 134', the pinion 140' will be rotated,
 which will rotate the ball 146. Rotation of the ball 146 results in
 longitudinal movement of the screw 148 and valve member 34'. The direction
 of longitudinal movement depends on the direction of rotation of the
 pinion 140'. Additional valve members may be controlled by the motor 134'
 by disposing an idler gear 150 between the ball 146 and another ball 146'
 of another ball and screw assembly 144', to which another valve member may
 be connected. Any number of additional valve members may be controlled by
 the motor 134' in this manner.
 The flow control apparatus 10 of the present invention may be used to
 remotely control the production of hydrocarbons from a producing formation
 or to inject fluids (e.g., injection chemicals) from the earth's surface
 into a well and/or producing formation. If used to produce hydrocarbons
 from a formation, the apparatus 10 is preferably connected to a production
 tubing (not shown) with the first end 14 of the body member 12 nearer the
 earth's surface than the second end 16 of the body member 12. If, on the
 other hand, the apparatus 10 is used to inject chemicals from the earth's
 surface, then it is preferably connected to a production tubing (not
 shown) with the second end 16 of the body member 12 nearer the earth's
 surface than the first end 14 of the body member 12.
 While the foregoing is directed to the preferred embodiment of the present
 invention, other and further embodiments of the invention may be devised
 without departing from the basic scope thereof, and the scope thereof is
 determined by the claims which follow. It is the express intention of the
 applicant not to invoke 35 U.S.C. .sctn. 112, paragraph 6 for any
 limitations of any of the claims herein, except when the claim expressly
 uses the words "means for" together.