Downhole sub with hydraulically actuable sleeve valve

[0001] This application is a continuation-in-part of PCT application no. PCT/CA2009/000599, filed Apr. 29, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/405,185, filed Mar. 16, 2009.

[0002] This application claims priority to U.S. provisional application Ser. No. 61/287,150, filed Dec. 16, 2009. This application also claims priority through the above-noted PCT application to U.S. provisional application Ser. No. 61/048,797, filed Apr. 29, 2008.

[0003] In downhole tubular strings, hydraulic pressure may be used to actuate various components. For example, packers may be pressure set, sleeve valves may be provided that are hydraulically moveable to open ports.

[0004] Although hydraulically actuable components are useful, difficulties can arise when there is more than one hydraulically actuable component to be separately actuated. In a system including pressure set packers and sleeve valves for tubular ports, difficulties have occurred when attempting to open the sleeve valves after the packers have been set.

[0005] Also, difficulties have occurred in strings where it is desired to run in the string with all ports closed by hydraulically actuable sleeve valves and then to open the sleeves at a selected time. If one port opens first, it is difficult to continue to hold pressure to move the sleeves from the remaining ports.

[0006] In accordance with a broad aspect of the present invention, there is provided a hydraulically actuable sleeve valve comprising: a tubular segment including a wall defining therein an inner bore; a port through the wall of the tubular segment; a sleeve supported by the tubular segment and installed to be axially moveable relative to the tubular segment from a first position covering the port to a second position and to a third position away from a covering position over the port, the sleeve including a first piston face open to tubing pressure and a second piston face open to annular pressure, such that a pressure differential can be set up between the first piston face and the second piston face to drive the sleeve toward a low pressure side from the first position into the second position with the sleeve continuing to cover the port; and a driver to move the sleeve from the second position into the third position, the driver being unable to move the sleeve until the pressure differential is substantially dissipated.

[0007] In accordance with another broad aspect of the present invention there is provided a method for opening a port through the wall of a ported sub, the method comprising: providing a sub with a port through its tubular side wall; providing a hydraulically actuable valve to cover the port, the valve being actuable to move away from a position covering the port to thereby open the port; increasing pressure within the sub to create a pressure differential across the valve to move the valve toward the low pressure side, while the port remains closed by the valve; thereafter, reducing pressure within the sub to reduce the pressure differential; and driving the valve to move it away from a position covering the port.

[0008] In accordance with another broad aspect of the present invention there is provided a wellbore tubing string assembly, comprising: a tubing string; and a first plurality of sleeve valves carried along the tubing string, each of the first plurality of sleeve valves capable of holding pressure when a tubing pressure within the tubing string is greater than an annular pressure about the tubing string and the first plurality of sleeve valves being driven to open at substantially the same time as the tubing pressure is substantially equalized with the annular pressure.

[0009] In accordance with another broad aspect of the present invention there is provided a method of accessing a hydrocarbon laden formation comprising: providing a plurality of fluid flow regulating mechanisms; constructing a tubing string wherein the plurality of fluid flow regulating mechanisms are grouped into a plurality of areas including a first area including one or more of the plurality of fluid flow regulating mechanisms and a second area including one or more of the plurality of fluid flow regulating mechanisms; placing the tubing string into a wellbore passing into the hydrocarbon laden formation; actuating substantially simultaneously all of the fluid flow regulating mechanisms comprising the first area to access the hydrocarbon laden formation along the first area; and actuating substantially simultaneously all of the fluid flow regulating mechanisms comprising the second area to access the hydrocarbon laden formation along the second area.

[0010] In accordance with another broad aspect, there is provided a sleeve valve sub comprising: a tubular segment including a wall defining therein an inner bore; a first port through the wall of the tubular segment; a second port through the wall of the tubular segment; and, a sleeve supported by the tubular segment and installed to be axially moveable relative to the tubular segment from a first position covering the first port to a second position away from a covering position over the first port, the sleeve covering second port in the first position and the second position, the sleeve including an inner facing surface defining a full bore diameter, an inner diameter constriction on the inner diameter of the sleeve having a diameter less than the full bore diameter; an outer facing surface, an indentation on the outer facing surface radially aligned with the inner diameter constriction, the indentation defined by a extension of the outer facing surface protruding inwardly of the full bore diameter, the indentation being positionable over the second port when the sleeve is in the second position such that the second port is openable to fluid flow therethrough by removal of the inner diameter constriction.

[0011] It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

[0036] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles of various aspects of the present invention. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the invention in its various aspects. In the description, similar parts are marked throughout the specification and the drawings with the same respective reference numerals. The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order more clearly to depict certain features.

[0037] Referring to the Figures, a hydraulically actuable sleeve valve 10 for a downhole tool is shown. Sleeve valve 10 may include a tubular segment 12, a sleeve 14 supported by the tubular segment and a driver, shown generally at reference number 16, to drive the sleeve to move.

[0038] Sleeve valve 10 may be intended for use in wellbore tool applications. For example, the sleeve valve may be employed in wellbore treatment applications. Tubular segment 12 may be a wellbore tubular such as of pipe, liner casing, etc. and may be a portion of a tubing string. Tubular segment 12 may include a bore 12a in communication with the inner bore of a tubing string such that pressures may be controlled therein and fluids may be communicated from surface therethrough, such as for wellbore treatment. Tubular segment 12 may be formed in various ways to be incorporated in a tubular string. For example, the tubular segment may be formed integral or connected by various means, such as threading, welding etc., with another portion of the tubular string. For example, ends 12b, 12c of the tubular segment, shown here as blanks, may be formed for engagement in sequence with adjacent tubulars in a string. For example, ends 12b, 12c may be formed as threaded pins or boxes to allow threaded engagement with adjacent tubulars.

[0039] Sleeve 14 may be installed to act as a piston in the tubular segment, in other words to be axially moveable relative to the tubular segment at least some movement of which is driven by fluid pressure. Sleeve 14 may be axially moveable through a plurality of positions. For example, as presently illustrated, sleeve 14 may be moveable through a first position (FIG. 1A), a second position (FIG. 1B) and a final or third position (FIG. 1C). The installation site for the sleeve in the tubular segment is formed to allow for such movement.

[0040] Sleeve 14 may include a first piston face 18 in communication, for example through ports 19, with the inner bore 12a of the tubular segment such that first piston face 18 is open to tubing pressure. Sleeve 14 may further include a second piston face 20 in communication with the outer surface 12d of the tubular segment. For example, one or more ports 22 may be formed from outer surface 12d of the tubular segment such that second piston face 20 is open to annulus, hydrostatic pressure about the tubular segment. First piston face 18 and second piston face 20 are positioned to act oppositely on the sleeve. Since the first piston face is open to tubing pressure and the second piston face is open to annulus pressure, a pressure differential can be set up between the first piston face and the second piston face to move the sleeve by offsetting or adjusting one or the other of the tubing pressure or annulus pressure. In particular, although hydrostatic pressure may generally be equalized between the tubing inner bore and the annulus, by increasing tubing pressure, as by increasing pressure in bore 12a from surface, pressure acting against first piston face 18 may be greater than the pressure acting against second piston face 20, which may cause sleeve 14 to move toward the low pressure side, which is the side open to face 20, into a selected second position (FIG. 1B). Seals 18a, such as o-rings, may be provided to act against leakage of fluid from the bore to the annulus about the tubular segment such that fluid from inner bore 12a is communicated only to face 18 and not to face 20.

[0041] One or more releasable setting devices 24 may be provided to releasably hold the sleeve in the first position. Releasable setting devices 24, such as one or more of a shear pin (a plurality of shear pins are shown), a collet, a c-ring, etc. provide that the sleeve may be held in place against inadvertent movement out of any selected position, but may be released to move only when it is desirable to do so. In the illustrated embodiment, releasable setting devices 24 may be installed to maintain the sleeve in its first position but can be released, as shown sheared in FIGS. 1B and 1C, by differential pressure between faces 18 and 20 to allow movement of the sleeve. Selection of a releasable setting device, such as shear pins to be overcome by a pressure differential is well understood in the art. In the present embodiment, the differential pressure required to shear out the sleeve is affected by the hydrostatic pressure and the rating and number of shear pins.

[0042] Driver 16 may be provided to move the sleeve into the final position. The driver may be selected to be unable to move the sleeve until releasable setting device 24 is released. Since driver 16 is unable to overcome the holding power of releasable setting devices 24, the driver can only move the sleeve once the releasable setting devices are released. Since driver 16 cannot overcome the holding pressure of releasable setting devices 24 but the differential pressure can overcome the holding force of devices 24, it will be appreciated then that driver 16 may apply a driving force less than the force exerted by the differential pressure such that driver 16 may also be unable to overcome or act against a differential pressure sufficient to overcome devices 24. Driver 16 may take various forms. For example, in one embodiment, driver 16 may include a spring 25 (FIG. 2) and/or a gas pressure chamber 26 (FIG. 1) to apply a push or pull force to the sleeve or to simply allow the sleeve to move in response to an applied force such as an inherent or applied pressure differential or gravity. In the illustrated embodiment of FIG. 1, driver 16 employs hydrostatic pressure through piston face 20 that acts against trapped gas chamber 26 defined between tubular segment 12 and sleeve 14. Chamber 26 is sealed by seals 18a, 28a, such as o-rings, such that any gas therein is trapped. Chamber 26 includes gas trapped at atmospheric or some other low pressure. Generally, chamber 26 includes air at surface atmospheric pressure, as may be present simply by assembly of the parts at surface. In any event, generally the pressure in chamber 26 is somewhat less than the hydrostatic pressure downhole. As such, when sleeve 14 is free to move, a pressure imbalance occurs across the sleeve at piston face 20 causing the sleeve to move toward the low pressure side, as provided by chamber 26, if no greater forces are acting against such movement.

[0043] In the illustrated embodiment, sleeve 14 moves axially in a first direction when moving from the first position to the second position and reverses to move axially in a direction opposite to the first direction when it moves from the second position to the third position. In the illustrated embodiment, sleeve 14 passes through the first position on its way to the third position. The illustrated sleeve configuration and sequence of movement allows the sleeve to continue to hold pressure in the first position and the second position. When driven by tubing pressure to move from the first position into the second position, the sleeve moves from one overlapping, sealing position over port 28 into a further overlapping, port closed position and not towards opening of the port. As such, as long as tubing pressure is held or increased, the sleeve will remain in a port closed position and the tubing string in which the valve is positioned will be capable of holding pressure. The second position may be considered a closed but activated or passive position, wherein the sleeve has been acted upon, but the valve remains closed. In the presently illustrated embodiment, the pressure differential between faces 18 and 20 caused by pressuring up in bore 12c does not move the sleeve into or even toward a port open position. Pressuring up the tubing string only releases the sleeve for later opening. Only when tubing pressure is dissipated to reduce or remove the pressure differential, can sleeve 14 move into the third, port open position.

[0044] While the above-described sleeve movement may provide certain benefits, of course other directions, traveling distances and sequences of movement may be employed depending on the configuration of the sleeve, piston chambers, releasable setting devices, driver, etc. In the illustrated embodiment, the first direction, when moving from the first position to the second position, may be towards surface and the reverse direction may be downhole.

[0045] Sleeve 14 may be installed in various ways on or in the tubular segment and may take various forms, while being axially moveable along a length of the tubular segment. For example, as illustrated, sleeve 14 may be installed in an annular opening 27 defined between an inner wall 29a and an outer wall 29b of the tubular segment. In the illustrated embodiment, piston face 18 is positioned at an end of the sleeve in annular opening 27, with pressure communication through ports 19 passing through inner wall 29a. Also in this illustrated embodiment, chamber 26 is defined between sleeve 14 and inner wall 29a. Also shown in this embodiment but again variable as desired, an opposite end of sleeve 14 extends out from annular opening 27 to have a surface in direct communication with inner bore 12a. Sleeve 14 may include one or more stepped portions 31 to adjust its inner diameter and thickness. Stepped portions 31, if desired, may alternately be selected to provide for piston face sizing and force selection. In the illustrated embodiment, for example, stepped portion 31 provides another piston face on the sleeve in communication with inner bore 12a, and therefore tubing pressure, through ports 33. The piston face of portion 31 acts with face 20 to counteract forces generated at piston face 18. In the illustrated embodiment, ports 33 also act to avoid a pressure lock condition at stepped portion 31. The face area provided by stepped portion 31 may be considered when calculating the total piston face area of the sleeve and the overall pressure effect thereon. For example, faces 18, 20 and 31 must all be considered with respect to pressure differentials acting across the sleeve and the effect of applied or inherent pressure conditions, such as applied tubing pressure, hydrostatic pressure acting as driver 16. Faces 18, 20 and 31 may all be considered to obtain a sleeve across which pressure differentials can be readily achieved.

[0046] In operation, sleeve 14 may be axially moved relative to tubular segment 12 between the three positions. For example, as shown in FIG. 1A, the sleeve valve may initially be in the first position with releasable setting devices 24 holding the sleeve in that position. To move the sleeve to the second position shown in FIG. 1B, pressure may be increased in bore 12a, which pressure is not communicated to the annulus, such that a pressure differential is created between face 18 and face 20 across the sleeve. This tends to force the sleeve toward the low pressure side, which is the side at face 20. Such force releases devices 24, for example shears the shear pins, such that sleeve 14 can move toward the end defining face 20 until it arrives at the second position (FIG. 1B). Thereafter, pressure in bore 12a can be allowed to relax such that the pressure differential is reduced or eliminated between faces 18 and 20. At this point, since the sleeve is free from the holding force of devices 24, once the pressure differential is sufficiently reduced, the force in driver 16 may be sufficient to move the sleeve into the third position (FIG. 1C). In the illustrated embodiment, for example, the hydrostatic pressure may act on face 20 and, relative to low pressure chamber 26, a pressure imbalance is established that may tend to drive sleeve 14 to the third, and in the illustrated embodiment of FIG. 1C, final position.

[0047] As such, a pressure increase within the tubular segment causes a pressure differential that releases the sleeve and renders the sleeve into a condition such that it can be acted upon by a driving force to move the sleeve to a further position. Pressuring up is only required to release the sleeve and not to move the sleeve into a port open position. In fact, since any pressure differential where the tubing pressure is greater than the annular pressure holds the sleeve in a port-closed, pressure holding position, the sleeve can only be acted upon by the driving force once the tubing pressure generated differential is dissipated. The sleeve may, therefore, be actuated by pressure cycling wherein a pressure increase within the tubular segment causes a pressure differential that releases the sleeve and renders the sleeve in a condition such that it can be acted upon by a driver, such as existing hydrostatic pressure, to move the sleeve to a further position.

[0048] The sleeve valve of the present invention may be useful in various applications where it is desired to move a sleeve through a plurality of positions, where it is desired to actuate a sleeve to open after increasing tubing pressure, where it is desired to open a port in a tubing string hydraulically but where the fluid pressure must be held in the tubing string for other purposes prior to opening the ports to equalize pressure and/or where it is desired to open a plurality of sleeve valves in the tubing string hydraulically at substantially the same time without a risk of certain of the valves failing to open due to pressure equalization through certain others of the valves that opened first. In the illustrated embodiment, for example, sleeve 14 in both the first and second positions is positioned to cover port 28 and seal it against fluid flow therethrough. However, in the third position, sleeve 14 has moved away from port and leaves it open, at least to some degree, for fluid flow therethrough. Although a tubing pressure increase releases the sleeve to move into the second position, the valve can still hold pressure in the second position and, in fact, tubing pressure creating a pressure differential across the sleeve actually holds the sleeve in a port closed position. Only when pressure is released after a pressure up condition, can the sleeve move to the port open position. Seals 30 may be provided to assist with the sealing properties of sleeve 14 relative to port 28. Such port 28 may open to an annular string component, such as a packer to be inflated, or may open bore 12a to the annular area about the tubular segment, such as may be required for wellbore treatment or production. In one embodiment, for example, the sleeve may be moved to open port 28 through the tubular segment such that fluids from the annulus, such as produced fluids can pass into bore 12a. Alternately, the port may be intended to allow fluids from bore 12a to pass into the annulus.

[0049] In the illustrated embodiment, for example, a plurality of ports 28 pass through the wall of tubular segment 12 for passage of fluids between bore 12a and outer surface 12d and, in particular, the annulus about the string. In the illustrated embodiment ports 28 each include a nozzle insert 35 for jetting fluids radially outwardly therethrough. Nozzle insert 35 may include a convergent type orifice, having a fluid opening that narrows from a wide diameter to a smaller diameter in the direction of the flow, which is outwardly from bore 12a to outer surface 12d. As such, nozzle insert 35 may be useful to generate a fluid jet with a high exit velocity passing through the port in which the insert is positioned. Alternately or in addition, ports 28 may have installed therein a choking device for regulating the rate or volume of flow therethrough, such as may be useful in limited entry systems. Port configurations may be selected and employed, as desired. For example, the ports may operate with or include screening devices. In another embodiment, the ports may communicate with inflow control device (ICD) channels such as those acting to create a pressure drop for incoming production fluids.

[0050] As illustrated, valve 10 may include one or more locks, as desired. For example, a lock may be provided to resist sleeve 14 of the valve from moving from the first position directly to the third position and/or a lock may be provided to resist the sleeve from moving from the third position back to the second position. In the illustrated embodiment, for example, an inwardly biased c-ring 32 is installed to act between a shoulder 34 on tubular member 12 and a shoulder 36 on sleeve 14. By acting between the shoulders, they cannot approach each other and, therefore, sleeve 14 cannot move from the first position directly toward the third position, even when shear pins 24 are no longer holding the sleeve. C-ring 32 does not resist movement of the sleeve from the first position to the second position. However, the c-ring may be held by another shoulder 38 on tubular member 12 against movement with the sleeve, such that when sleeve 14 moves from the first position to the second position the sleeve moves past the c-ring. Sleeve 14 includes a gland 40 that is positioned to pass under the c-ring as the sleeve moves and, when this occurs, c-ring 32, being biased inwardly, can drop into the gland. Gland 40 may be sized to accommodate the c-ring no more than flush with the outer diameter of the sleeve such that after dropping into gland 40, c-ring 32 may be carried with the sleeve without catching again on parts beyond the gland. As such, after c-ring 32 drops into the gland, it does not inhibit further movement of the sleeve.

[0051] Another lock may be provided, for example, in the illustrated embodiment to resist movement of the sleeve from the third position back to the second position. The lock may also employ a device such as a c-ring 42 with a biasing force to expand from a gland 44 in sleeve 14 to land against a shoulder 46 on tubular member 12, when the sleeve carries the c-ring to a position where it can expand. The gland for c-ring 42 and the shoulder may be positioned such that they align when the sleeve moves substantially into the third position. When c-ring 42 expands, it acts between one side of gland 44 and shoulder 46 to prevent the sleeve from moving from the third position back toward the second position.

[0052] The tool may be formed in various ways. As will be appreciated, it is common to form wellbore components in tubular, cylindrical form and oftentimes, of threadedly or weldedly connected subcomponents. For example, tubular segment in the illustrated embodiment is formed of a plurality of parts connected at threaded intervals. The threaded intervals may be selected to hold pressure, to form useful shoulders, etc., as desired.

[0053] It may be desirable in some applications to provide the sleeve valve with a port-reclosable function. For example, in some applications it may be useful to open ports 28 to permit fluid flow therethrough and then later close the ports to shut in the well. This reclosure may be useful for wellbore treatment (i.e. soaking), for back flow or production control, etc. As such sleeve 14 may be moveable from the third position to a position overlying and blocking flow through ports. Alternately, in another embodiment with reference to FIG. 2, another downhole tool may be provided with a sleeve valve including a sleeve 48 in a tubular segment 49, the sleeve being moveable from a position initially overlying and closing ports 50 to a position away from the ports (as shown), wherein ports 50 become opened for fluid flow therethrough. To provide a reclosable functionality for ports 50, tubular segment 49 may include a second sleeve 51 that is positioned adjacent ports 50 and moveable from a position away from the ports to a position overlying and closing them. Second sleeve 51, for example, may be positioned on a side of the ports opposite sleeve 48 and can be moved into place when and if it is desired to close the ports. Sleeve 51 may include seals 52 to seal between the tubular segment and the sleeve, if desired. Sleeve 51 may be capable of moving in any of various ways. In one embodiment, for example, sleeve 51 may include a shifting catch groove 53 allowing it to be engaged and moved by a shifting tool conveyed and manipulated from surface. Alternately, sleeve 51 may include seat to catch a drop plug so that it can be moved into a sealing position over the ports. Sleeve 51 may include a releasable setting device such as a shear pin, a collet or a spring that holds the sleeve in place until the holding force of the releasable setting device is overcome. Sleeve 51 may be reopenable, if desired, by engaging the sleeve again and moving it away from ports 50. Another valve according to an aspect of the present invention is shown in FIG. 18. In this embodiment, the valve is designed to allow for a single pressure cycle to move the valve from a first, closed position (as shown), to a second closed and activated position and thereafter it cycles from the closed activated position to a third, open position. The valve may be moved from the closed position to the closed and activated position by differential pressure from tubing to annulus and may include a driver to bias the sleeve from the closed but activated position to the open position. The valve driver may include a spring, a pressure chamber containing nitrogen or atmospheric gas that will be worked on by hydrostatic pressure or applied pressure in the wellbore.

[0054] The valve of FIG. 18 comprises an outer tube, also termed a housing 202 that has threaded ends 201 such that it is attachable to the tubing or casing string in the well. The outer tube in this embodiment, includes an upper housing 202a and a lower housing 202b that are threaded together to form the final housing. The outer housing has a port 204 through its side wall that is closed off by an inner tube 213 that serves both as a sealing sleeve and as a piston. As the tool is assembled, a spring 206 is placed to act between the inner tube and the housing. It shoulders against an upset 205 in the outer housing. The inner tube is installed with seals 209 and 203 that form a seal between the housing and the inner tube, and that seal above and below ports 204 in the outer housing.

[0055] Seals 203, 209 are positioned to create a chamber 212 in communication with the outer surface of the housing through ports. As such, a piston face 210 is formed on the inner tube that can be affected by pressure differentials between the inner diameter of the housing and the annulus.

[0056] When the inner tube 213 is installed, it traps the spring 206 between a shoulder 207 on the inner tube and upset shoulder 205 on the housing and radially between itself and the housing. As the inner tube is pushed into place, it compresses the spring 206. The spring is compressed and the inner tube is pushed into the outer tube until a slot in the piston becomes lined up with the shear screw holes in the outer housing. Once this alignment is achieved, shear screws 208 are installed locking the inner tube in position.

[0057] As the inner tube of a sleeve valve in generally positioned, in an annular groove to avoid restriction of the inner diameter, it is noted that a gap 215 remains between the top of the inner tube and any shoulder 214 forming the upper end of the annular groove. This gap is required to allow movement of the inner tube within the housing. In particular, pressure applied internally will act against piston face 210 and force the inner tube to move upward (away from the end on which piston face 210 is formed). This upward movement will load into the shear pins. Once the force from the internal pressure is increased to a predetermined amount, it will shear the pins 208 allowing the inner tube to move upward until the upper end of the inner tube contacts the shoulder 214 on the housing. When the piston is forced against the housing shoulder, the valve is positioned in the activated and closed position.

[0058] The valve will remain in the activated and closed position as long as the internal pressure is sufficient to keep the spring compressed. The pressure differential across face 210 prevents the sleeve from moving down. The tubing pressure can be maintained for an indefinite period of time. Once the pressure differential between the tubing inner diameter and the chamber 212 (which is annular pressure) is dissipated such that the force of spring can overcome the holding force across face 210, the inner tube will be driven down to open the ports.

[0059] As the spring expands, it pushes against the shoulders 205 and 207 and moves the inner tube down so that the upper seals 203 move below the port 204 in the outer housing. The valve is then fully open, and fluids from inside the tubing string can be pumped into the annulus, or can be produced from the annulus into the tubing.

[0060] The valve can also contain a locking device to keep it in the open position or it can contain the ability to close the piston by forcing it back into the closed position. It may also contain a separate closing sleeve to allow a sleeve to move across the port 204, if required.

[0061] While the sleeve is held by tubing pressure against shoulder 214, pressure can be held in the tubing string. At this time tubing or casing pressure operations can be conducted, if desired, such as setting hydraulically actuated packers, such as hydraulically compressible or inflatable packers. Once pressure operations are conducted and completed, the pressure between the tubing and annulus can be adjusted towards equalization, which will allow the driver to open the ports closed by the inner tube.

[0062] Several of these valves can be run in a tubing string, and can be moved to the activated but closed and the open positions substantially simultaneously.

[0063] The pressures on either side of piston face 210 can be adjusted toward equalization by releasing pressure on the tubing at surface, or by opening a hydraulic opened sleeve or pump-out plug downhole. For example, once a single valve is opened, allowing the pressure to equalize inside and outside of the tubing, all the valves in the tubing string that have been activated will be moved to the open position by the driver, which in this case is spring 206. In one embodiment, for example, a plurality of sleeves as shown in FIG. 18 can be employed that become activated but closed at about 2500 to 3500 psi and additionally a hydraulically openable port could be employed that moves directly from a closed to an open position at a pressure above 3500 psi, for example at about 4000 psi, to provide for pressure equalization on demand. As such, an increase in tubing pressure to at least 2500 psi would cause the inner tubes of the valves of FIG. 18 to be activated but held closed and, while the inner tubes are held in a closed position, tubing pressure could be further increased to above 3500 psi to open the port to cause equalization, thereby dissipating the pressure differential to allow the inner tubes to move away from ports 204, as driven by spring 206. A suitable hydraulically openable sleeve is available as a FracPORT™ product from Packers Plus Energy Services Inc.

[0064] These tools can be run in series with other similar devices to selectively open several valves at the same time. In addition, several series of these tools can be run, with each series having a different activation pressure.

[0065] As shown in FIG. 3, a downhole tool including a valve according to the present invention can be used in a wellbore string 58 where it is desired to activate multiple sleeves on demand and at substantially the same time. For example, in a tubular string carrying a plurality of ICD or screen devices 60, sleeve valves, such as one of those described herein above or similar, can be used to control fluid flow through the ports of devices 60. Such sleeve valves may also or alternately be useful where the tubing string carries packers 62 that must first be pressure set before the sleeves can be opened. In such an embodiment, for example, the pressure up condition required to set the packers may move the sleeves into the second position, where they continue to cover ports and hold pressure, and a subsequent pressure relaxation may then allow the sleeves to be driven to open the ports in devices 60 to permit fluid flow therethrough. Of course, even if the tubing string does not include packers, there may be a desire to install a tubing string with its flow control devices 60 in a closed (non-fluid conveying) condition and to open the devices all at once and without physical manipulation thereof and without a concern of certain devices becoming opened to fluid flow while others fail to open because of early pressure equalization caused by one sleeve valve opening before the others (i.e. although the sleeve valves are released hydraulically to be capable of opening, even if one sleeve opens its port first, the others are not adversely affected by such opening). In such applications, the sleeve valves described herein may be useful installed in, on or adjacent devices 60 to control fluid flow therethrough. One or more sleeve valve may be installed to control flow through each device 60.

[0066] An indexing J keyway may be installed between the sleeve and the tubular segment to hold the sleeve against opening the ports until a selected number of pressure cycles have been applied to the tubing string, after which the keyway releases the sleeve such that the driver can act to drive the sleeve to the third, port open position. An indexing J keyway may be employed to allow some selected sleeves to open while others remain closed and only to be opened after a selected number of further pressure cycles. The selected sleeves may be positioned together in the well or may be spaced apart.

[0067] For example, referring to the drawings and particularly to FIGS. 4-9, there is shown an apparatus 120 for placing in a wellbore through a formation to effect fluid handling therethrough. In this embodiment, the apparatus is described for fluid handling is for the purpose of wellbore stimulation, and in particular fracing. However, the fluid handling could also be for the purposes of handling produced fluids.

[0068] The illustrated apparatus 120 comprises the plurality of fracing mechanisms 121, 122 each of which includes at least one port 142 through which fluid flow may occur. A plurality of packers 124 are positioned with one or more fracing mechanisms 121, 122 therebetween along at least a portion of the length of the apparatus 120. In some cases, only one fracing mechanism is positioned between adjacent packers, such as in Area I, while in other cases there may be more than one fracing mechanism between each set of adjacent packers, as shown in Area VIII. Although the packers 124 are generically illustrated in FIGS. 4-9, the packers 124 may, for example, comprise Rockseal® packers of the type manufactured and sold by Packers Plus Energy Services Inc. of Calgary, Alberta, Canada, hydraulically actuable swellable polymer packers, inflatable packers, etc.

[0069] By way of example, the apparatus 120 in the illustration is divided into eight areas designated as Areas I-VIII (Areas III through VII are omitted in the drawings for clarity). In this example, as illustrated, each area comprises four fracing mechanisms 121 or 122 which are designated in FIGS. 4-9, inclusive, by the letters A, B, C and D. Thus, the apparatus 120 comprises thirty-two fracing mechanisms 121, 122. As will be understood by those skilled in the art, the apparatus 120 may comprise as many fracing mechanisms as may be required for particular applications of the invention, the fracing mechanisms can be arranged in one or more areas as may be required for particular applications of the invention, and each area may comprise one or more fracing mechanisms depending upon the requirements of particular applications of the invention. The amount of fracing fluid that can exit each of the ports of the fracing mechanisms, when they are open, may be controlled by the sizing of the individual frac port nozzles. For example, the ports may be selected to provide limited entry along an Area. Limited entry technology relies on selection of the number, size and placement of fluid ports 142 along a selected length of a tubing string such that critical or choked flow occurs across the selected ports. Such technology ensures that fluid can be passed through the ports in a selected way along the selected length. For example, rather than having uneven flow through ports 142 of mechanisms 122 A, B, C and D in Area VIII, a limited entry approach may be used by selection of the rating of choking inserts in ports 142 to ensure that, under critical flow conditions, an amount of fluid passes through each port at a substantially even rate to ensure that a substantially uniform treatment occurs along the entirety of the wellbore spanned by Area VIII of the apparatus.

[0070] Referring first to FIGS. 4 and 5, the apparatus 120 is initially positioned in a hydrocarbon well with each of the packers 124 being in its non-actuated state. The distal end of the tubing string comprising the apparatus 120 may be initially open to facilitate the flow of fluid through the tubing string and then back through at least a portion of the well annulus toward surface to condition the well. At the conclusion of the conditioning procedure, a ball 126 is passed through the tubing string until it engages a ball receiving mechanism 128, such as a seat, thereby closing the distal end of the tubing string. After the ball 126 has been seated, the tubing string is pressurized thereby actuating the packers 124. FIG. 5 illustrates the apparatus 120 after the packers 124 have been actuated.

[0071] All of the fracing mechanisms in a single area can be opened at the same time. In other words, fracing mechanisms 121 A, B, C and D that reside in Area I (the area nearest the lower end of the well) all open at the same time which occurs after pressurization takes place after ball 126 seats. The fracing mechanisms 122 A, B, C and D, etc. of Areas II, III, etc. remain closed during the opening of fracing mechanisms 121 of Area I and possibly even during any fracing therethrough. Once the Area I mechanisms are open, and if desired the frac is complete, another ball 126a is dropped that lands in a ball receiving mechanism 128a above the top fracing mechanism 121D in Area I. This ball provides two functions; first, it seats and seals off the open fracing mechanisms 121 in Area I; and second, it allows pressure to be applied to the fracing mechanisms 122 that are located above Area I. This next pressurization opens all of the fracing ports in Area II (which is located adjacent to and up-hole from Area I in the string). At the same time, the fracing mechanisms in Area III and higher remain closed. After completing a frac in Area II, another ball is dropped that seats above the fracing mechanisms in Area II and below the fracing mechanisms in Area III, the string is pressured up to open the mechanisms of Area III, and so on.

[0072] The fracing mechanisms 121 of Area I may be as described above in FIG. 1 or 2, such that they may be opened all at once by a single pressure pulse. For example, the mechanisms may be released to open by an increase in tubing pressure as affected after ball 126 seats and when packers are being set and may be driven to open as tubing pressure is released. However, the fracing mechanisms 122 of the remaining areas remain closed during the initial pressure cycle and only open after a second or further pressure up condition in the string. FIGS. 10-17 illustrate the construction and operation of a possible fracing mechanism 122 of the apparatus 120. Fracing mechanism 122 comprises a tubular body including an upper housing 136 and a lower housing 138, which is secured to the upper housing 136. A sleeve-type piston 140 is slidably supported within the upper housing 136 and the lower housing 138. Piston 140 includes a face 149 acted upon by tubing pressure, while the opposite end of the piston is open to annular pressure. The upper housing 136 is provided with a plurality of frac ports 142. The number, diameter and construction of the frac ports 142 may vary along the length of the tubing string, depending upon the characteristics of various zones and desired treatments to be effected within the hydrocarbon well. The frac ports are normally closed by the piston 140 and are opened when apertures 144 formed in the piston 140 are positioned in alignment with the frac ports 142. The fracing mechanism includes a driver such as an atmosphere trap 143, a spring, etc.

[0073] FIG. 10 illustrates the fracing mechanism 122 with the piston 140 in its lower most position.

[0074] FIG. 11 illustrates the fracing mechanism 122 with the piston 140 located somewhere above its location as illustrated in FIG. 10, as driven by pressure applied against face 149 which is greater than annular pressure.

[0075] FIG. 12 illustrates the frac port 122 with the piston 140 in its uppermost position wherein the apertures 144 align with the frac ports 142.

[0076] Referring to FIG. 13, the piston 140 of each fracing mechanism 122 is provided with a slot 146 which engages, and rides over a J-pin 148 as shown in FIGS. 10-12. The J-pin 148 is installed, as by sealable engagement with the upper housing 136.

[0077] FIG. 14 illustrates, as an example, the profile of the slot 146a formed in the exterior wall of the piston 140 for use in all Area II mechanisms. The J-pin 148 initially resides in position 1 in the slot 146a. When the apparatus 120 is first pressurized to set the packers 124, the piston moves as by pressure applied against face 149, so that the J-pin 148 resides in position 2. When the pressure is released, the piston is driven, as by hydrostatic pressure creating a differential relative to chamber 143, so that the J-pin 148 resides in position 3, and when the apparatus 120 is pressurized the second time, the piston moves so that the J-pin 148 resides in position 4. Upon release of the second pressurization within the apparatus 120, the piston is biased by the driver so that the J-pin 148 resides in position 11 whereupon the apertures 144 in the piston 140 align with the frac ports 142 formed through the upper housing 136 of the fracing mechanism 122 thereby opening the ports at Area II and, if desired, facilitating fracing of the portion of the hydrocarbon well located at Area II. As will be appreciated by those skilled in the art, the fracing ports located in Area II are simultaneously opened upon the second pressurization and release thereof.

[0078] FIG. 15 illustrates the profile of a slot 146b for all Area III tools. The profile illustrated in FIG. 15 operates identically to the profile illustrated in FIG. 14 as described herein in conjunction therewith above except that an additional pressurization and release cycle is required for the J-pin to arrive at position 11, thereby aligning the apertures 144 in the piston 140 with the fracing ports 142 of the tool.

[0079] FIG. 16 illustrates the profile of the slot 146c for all Area IV tools. The configuration of slot 146c shown in FIG. 16 operates identically to that of the slot 146b shown in FIG. 15 except that an additional pressurization and release is necessary in order to bring the J-pin riding in slot 146c into position 11, thereby aligning the apertures 144 of the piston 140 with the fracing ports 142.

[0080] FIG. 17 illustrates the profile of the slot 146d as used in all of the Area V tools. The operation of the slot 146d of the Area V tools is substantially identical to that of the Area IV tools except that an additional pressurization and release is necessary in order to bring the J-pin riding in that slot to position 11 wherein the apertures 144 of the piston 140 are aligned with the fracing ports 142 to effect fracing of the Area V location of the well.

[0081] Those skilled in the art will understand that the pattern of the slots can be continued by wrapping the slot around the extension of the piston to the extent necessary to open all of the facing ports 142 comprising particular applications of the invention.

[0082] Those skilled in the art will also realize and appreciate that although the present invention has been described above and illustrated in the drawings as comprising eight areas other configurations can also be used depending upon the requirements of particular applications of the invention. For example, the number of areas comprising the invention can be equal to, greater than, or less than eight.

[0083] In the embodiments of FIGS. 10 to 12, the valves can be opened when it is selected to do so. As such if a string includes a plurality of pressure cycle operable valves, some valves can be opened while others remain closed. In that embodiment, the selective opening may be based on the number of pressure cycles applied to the valve. In another embodiment, valves can be opened when it is selected to do so, while others remain closed, as by isolation of tubing pressure from the valve piston until it is desired to open the valve piston to communication with the pressure cycles.

[0084] In one embodiment, for example the sub can include an isolator that isolates tubing pressure from the pressure actuated components of the sleeve until it is desired to open the sleeve to tubing pressure. For example, the tool of FIGS. 19 to 23 illustrate a sleeve valve sub installed in a tubing string, the sub including a tubular body 412 with fluid treatment/production ports 442 therethrough closed by a valve in the form of a sleeve 440 that is released for movement to open the ports by pressure cycling. In particular, in a similar manner to the sub of FIG. 1, the sleeve 440 of the sub of FIGS. 19 to 23 can be driven (by generating a pressure differential across the sleeve) from a first position to a second position, which allows the sleeve to be further acted upon by a driver 416 to move into a third position: opening the ports. However, the sleeve valve sub in this illustrated embodiment further includes an isolator, in this embodiment in the form of an isolation sleeve 470 that can, depending on its position, selectively isolate or allow communication of tubing pressure from/to sleeve 440. As such, sleeve 440 is not affected by tubing pressure and a pressure differential cannot be established, when the isolator, such as isolation sleeve 470, is in an active position but may be actuated by the tubing pressure when the isolator is disabled. The isolator may be actuated in various ways to open tubing pressure access to the piston face of sleeve 440. In the illustrated embodiment, for example, where the isolator includes isolation sleeve 470, the isolation sleeve may be moved along the tubular body from a position closing access to the piston face (FIG. 19) to a position allowing access to the piston face (FIG. 20).

[0085] The isolation sleeve includes seals 470a that isolate tubing pressure from the piston face of sleeve 440, when the sleeve is in the position closing access. However, sleeve 470 includes an access port 472 that can be moved into alignment with the tubing pressure fluid access channel to the piston face of sleeve 440 to allow tubing pressure communication to the piston face. If the sleeve overlies fluid treatment/production ports 442, the sleeve, when positioned to permit communication to the fluid access channel (FIG. 20), may also be retracted to permit ports to be open to some degree. In the illustrated embodiment, as will be better understood with reference to the description of sleeve 440 below, the fluid access channel to the sleeve's piston face is through fluid treatment/production ports 442 and, as such, the movement of access port 472 into alignment with the fluid access channel also serves to open ports 442. It will be appreciated that other arrangements may be possible depending on the length and form of isolation sleeve 470 and the form and positions of the fluid access channel and ports 442.

[0086] Isolation sleeve 470 may be moved, by any of various methods and/or mechanisms, along the tubular body from the position closing access to the piston face to the position allowing access to the piston face. For example, sleeve 470 may be moved using actuation by a downhole tool from surface, electrically or remotely by mechanical means unattached to surface. For example, in the illustrated embodiment, sleeve 470 may be moved by landing a ball 474 or other plugging device such as may include a dart, plug, etc., in a sleeve shifting seat 476 (FIG. 20). In such an embodiment, ball 474, which is selected to land and seal against seat 476, may be launched from surface to arrive at, as by fluid carriage or gravity, and seal against the seat. Fluid pressure may then be built up behind the ball to create a pressure differential to drive the sleeve along the tubular body 412 of the sub.

[0087] To better understand the operation of isolation sleeve 470 and sleeve 440, the operation of sleeve is discussed below.

[0088] As shown in the illustrated embodiment, for example, the sleeve valve sub may include tubular body 412 with ports 442 extending to provide fluid treatment/production communication between the inner bore 412a of the tubular body and its outer surface 412c. Ports 442 may be closed (FIGS. 19-21) and opened (FIG. 22) to fluid flow therethrough by a valve in the form of sleeve 440 that rides along the tubular body and, in this illustrated embodiment, axially along the outer surface of the tubular body. Because sleeve 440 is positioned on the outer surface, it may be subject to shocks during installation. As such the leading ends 440e, 441a of sleeve 440 and its support structure 441 may be chamfered to facilitate riding over structures and resist catching. While the illustrated embodiment shows sleeve 440 as riding along the outer surface, other positions are possible such as in an intermediate position or beneath an outer protective sleeve. Sleeve 440 includes a face 449 that can be acted upon by tubing pressure while an opposite face 420 is open to annular pressure. Tubing pressure is conveyed by a fluid channel defined in sequence through ports 442, an annulus 443 between tubular body 412 and sleeve 440, a channel (generally indicated at 445) and into chamber 447. Seals 440a, 440b, 440c, 440d contain and direct any fluid through the channel defined by the foregoing interconnected parts. Channel 445 can be provided in various forms such as bore drilled axially through sleeve 440, a groove formed along a surface of the sleeve, an installed conduit, etc. Details of the conduit are difficult to appreciate in the drawings, but conduit 445a may be installed along a surface of sleeve and have a fluid communication opening at one end to annulus 443 and a fluid communication opening at the opposite end to chamber 447. In the illustrated embodiment, conduit 445a is installed on the outer surface of sleeve 440 in a groove 445b formed therealong. By positioning of conduit 445a in groove 445b, the conduit is provided protection against the rigors of wellbore operations. Holes are opened through sleeve to provide access between the conduit's inner flow passage and both annulus 443 and chamber 447, respectively.

[0089] Annulus pressure is communicated to face 420 through unsealed interfaces such as the space 451 between the sleeve and set screws 424 or through other non pressure holding interfaces in sleeve that are open to face 420.

[0090] Sleeve 440 can be moved along the tubular body by creating a pressure differential between faces 449 and 420, for example by pressuring up the tubing string to increase the pressure against face 449, while that tubing pressure is sealed from communication to the annulus about the tool and, thereby, to face 420. Set screws 424 in glands 424a or other releasable setting devices retain the sleeve in a selected position on the tubular body, for example, in the run in position (FIG. 19) and until it is desired to begin the process to open the ports by generating a pressure differential sufficient to overcome the holding force of set screws (FIG. 21).

[0091] Driver, herein shown in the form of spring 416 (but alternately may be in the form of an atmospheric chamber, a pressurized chamber, an elastomeric insert, etc.), can be installed to act between the sleeve and tubular body to drive the sleeve once it is initially released to move (by application of a pressure differential). Spring 416 is a compression spring (biased against compression) which acts, when it is free to do so (FIG. 22), to drive the sleeve to reduce the volume of chamber 447, which is reverse to the direction traveled when the tubing pressure initially moves the sleeve.

[0092] Movement of the illustrated sleeve 440 to open ports 442 proceeds as follows, first a pressure differential may be set up across faces 449, 420 with the pressure acting against face 449 exceeding that acting against face 420 (FIG. 20-21). This pressure overcomes the holding force of screws 424 and drives the sleeve towards the low pressure side, which compresses spring 416 (FIG. 21). As long as the tubing pressure is held in excess of the force of spring to expand against its compressed state, the sleeve remains driven towards the low pressure side. However, when the pressure differential dissipates to the point that the spring force is greater than the force exerted by tubing pressure, the sleeve moves back by the driving force of the spring toward chamber 447 (FIG. 22). This movement opens the sub's ports to fluid flow therethrough by retracting the sleeve from a covering position over ports 442 through the tubular body.

[0093] In view of the foregoing, it can be now more fully appreciated that isolation sleeve 470 may be positioned to close or positioned to allow access of tubing pressure to the fluid channel arising through ports 442, according to the position of access ports 472 on the sleeve. When access ports 472 are in a position preventing fluid access to ports 442, any pressure fluctuations in the tubing string inner diameter through inner bore 412a are isolated from sleeve 440. However, when access ports 472 are at least to some degree open to ports 442, sleeve 440 may be acted upon by fluid pressure to retract the sleeve from ports 442 to open the ports to fluid flow, for formation treatment or production, through ports 472 and 442.

[0094] In some embodiments, it may be useful for the ball to continue past its seat after the sleeve has been moved. In such embodiments, yieldable seats or balls may be employed which allow a pressure differential to be set up to move the sleeve, but when the sleeve is stopped against further movement, such as by stopping against shoulder 478, the ball can pass through the seat. For example, the illustrated embodiment includes seat 476 that is yieldable. The ball 474 is capable of passing through the seat after the sleeve has shouldered into a stopped position. Thus, while the ball is seated in FIG. 20, the ball has passed through the seat in FIG. 21.

[0095] An isolator may be employed to open access to one sleeve at a time. If the isolator is a sleeve for example, the ball may land in the sleeve, move the sleeve and seal off fluid flow past the sleeve. If there is more than one isolator sleeve in a tubing string, the seats 476 of the sleeves may be differently sized such that different sized balls will seal in each of the two or more sleeves. In such an embodiment, the sleeve with the smallest ball is positioned below sleeves with larger seats in order to ensure that the ball capable of seating and sealing therein can pass through the seats above. In particular, where there are a plurality of sleeves with ball seats, each one that is to be actuated independently of the others and is progressively closer to surface, has a seat formed larger than the one below it in order to ensure that the balls can pass through any seats above that ball's intended seat.

[0096] In some embodiments, a plurality of isolators may be employed that are actuated by a common function. For example, if it is desired to segment the well, such as for example as shown in FIG. 4, into a plurality of areas with one or more selected fluid delivery mechanisms therein, one or more of the selected fluid delivery mechanisms in a selected area may have an isolator actuated by a common function. Using the illustrated embodiment of FIG. 19 as a reference, for example, a plurality of isolator sleeves may be employed in an area of the well that are each actuated by the same ball. In such an embodiment, the above-noted yieldable seats or balls may be employed which allow a pressure differential to be set up to move the sleeve, but when the sleeve is stopped against further movement, such as by stopping against shoulder 478, the ball can pass through the seat and move to the next seat, land therein to create a seal therewith and move that sleeve. This single ball driven multiple sleeve movement can continue until all the sleeves of interest are moved by the ball. Since it may be useful to have the ball create a final seal in the tubing string to restrict fluid access to structures above the finally seated ball, the final sleeve seat or a seat fixed below the final sleeve seat may be formed to prevent the ball from passing therethrough. While the ball and/or the seat may be yieldable, selecting the seat to be yieldable, rather than the ball may ensure that the finally seated ball is less likely to be expelled through its final seat and may avoid problems that may arise by plastic deformation of the ball. For example, a yieldable ball seat may be yieldable by material selection and/or by mechanical mechanisms. For example, the ball seat may be formed of a material yieldable under the intended pressure conditions such as an elastomer, a plastic, a soft metal, etc. that can elastically or plastically deform to allow a ball to pass. Alternately or in addition, the seat may include a solid or segmented surface with a biasing mechanism or failable component that can be overcome, biased out of the way or broken off, to allow the ball to pass. For a better understanding, reference may be made to FIG. 5 showing three areas I, II and VII in a well. While the apparatus of FIG. 5 has previously been described with respect to a foregoing tool embodiment of FIGS. 10 to 13, FIG. 5 can be useful also to illustrate possible operations with the tool embodiment of FIGS. 19 to 23. The apparatus 120 of FIG. 5 is initially positioned in a hydrocarbon well with each of the packers 124 being in a non-actuated state. The distal end of the tubing string comprising the apparatus 120 may be initially open to facilitate the flow of fluid through the tubing string and then back through at least a portion of the well annulus toward surface to condition the well. Of course, the end of the tubing string can alternately be closed during run in. However in the illustrated embodiment, a ball 126 is eventually passed through the tubing string until it engages a ball receiving mechanism 128, such as a seat, thereby closing the distal end of the tubing string. After the ball 126 has been seated, the tubing string is pressurized thereby actuating the packers 124. FIG. 5 illustrates the apparatus 120 after ball 126 has landed and the packers 124 have been actuated.

[0097] All of the fracing mechanisms in a single area can be opened at the same time. In other words, fracing mechanisms 121 A, B, C and D that reside in Area I (the area nearest the lower end of the well) all can be opened at the same time which occurs after pressurization takes place after ball 126 seats. The fracing mechanisms 122 A, B, C and D, etc. of Areas II, III, etc. remain closed during the opening of fracing mechanisms 121 of Area I and possibly even during any fracing therethrough. Once the Area I mechanisms are open, and if desired the frac is complete, it may be desired to open mechanisms 122 A, B, C and D, etc. of Areas II. To do so, we will assume here that each of the mechanisms include a sleeve-type isolator that isolates the pressure cycling, port opening sleeve from the tubing pressure such as for example shown in FIG. 19. The isolators in this embodiment may include a sleeve with a yieldable seat. To open the frac mechanisms, the isolation sleeves must be moved to permit tubing pressure to be communicated to the pressure cycling port-opening sleeves that control the open/closed condition of frac ports 142 A, B, C and D. To open the sleeves, another ball 126a (illustrated in FIG. 7) is dropped that lands in the seat of each isolator sleeve and moves each isolator sleeve to a position permitting communication to the pressure cycling sleeve. In particular, ball 126a would (i) first land in the seat of the isolator sleeve of mechanism 122 at port 142D, (ii) seal against the seat of that mechanism, (iii) shift, as driven by fluid pressure, the isolator sleeve, (iv) pass through that seat, (v) flow and land in the seat of the isolator sleeve of the next mechanism 122 at port 142C, (vi) seal against the seat of that isolator sleeve, (vii) shift, as driven by fluid pressure, the isolator sleeve, (viii) pass through that seat and so on until it passes through the seat of the last isolator sleeve at mechanism 122 of port 142A and arrives at ball receiving mechanism 128a above the top fracing mechanism 121D in Area I. In this position, ball 126a provides three functions; first, it has opened the isolator sleeves that have seats sized to accept and temporarily retain ball 126a; second, it has seated and created a seal between Area II and the open fracing mechanisms 121 in Area I; and third, it allows pressure to be applied and increased in the tubing string adjacent to the fracing mechanisms 122 that are located above Area I. It is to be appreciated that the last isolator sleeve seat could alternately be formed to retain the ball, rather than allowing it to pass to ball retainer 128a and still fulfill these three functions. After ball 126a lands in ball retainer 128a, the tubing pressure can again be elevated and this pressurization communicates to the pressure cycling sleeves to open all of the fracing ports 142 A, B, C and D in Area II (which is located adjacent to and up-hole from Area I in the string). At the same time, the fracing mechanisms in Area III and higher remain closed since their isolator sleeves remain positioned thereover: isolating their pressure cycling port-opening sleeves from tubing pressure. After completing a frac in Area II, another ball may be dropped that is sized to pass through the isolator sleeve seats and ball retaining mechanisms (if any) of Areas IV to VIII and to land in and seal against the isolator sleeve seats of the fracing mechanisms 122 of Area III. That ball also finally seats above the fracing mechanisms in Area II and below the fracing mechanisms in Area III, the string is pressured up to open the frac ports of Area III, and so on until all ports of interest are opened, such as in this illustrated embodiment, up to and including the frac ports 142 A, B, C and D of Area VIII.

[0098] The fracing mechanisms 121 of Area I may be as described above in FIG. 1 or 2, such that they may be opened all at once by a single pressure pulse. For example, the mechanisms may be released to open by an increase in tubing pressure as affected after ball 126 seats and when packers are being set and may be driven to open as tubing pressure is released. However, the fracing mechanisms 122 of the remaining areas remain closed during the initial pressure cycle and can only open after their isolator sleeves are opened and tubing pressure is increased and then dissipated to actuate their pressure cycling sleeves to open their ports.

[0099] The embodiment of FIGS. 19 to 23 further offer a feature facilitating production through the string after the fracing operation is complete. While production fluids may pass through aligned ports 442, 472, the illustrated tool includes further ports that may be opened only when it is desired to have greater access between inner bore 412a and the formation about the string. As such, the embodiment of FIGS. 19 to 23 includes production ports 482 (see FIG. 21) that may be opened when greater access through the tubular body 412 is desired between its inner bore 412a and its outer surface 412c. Production ports 482 may be normally covered by isolation sleeve 470. However, a sleeve of the sub may be openable by actuation or removal of a component thereof to open access from inner bore 412a to outer surface 412c through ports 482. Sleeve 470 in the illustrated embodiment includes a removable component in the form of a constriction 484 and opposite indentation 486 that is positioned to lie adjacent, in this embodiment radially inwardly of, the production ports. Constriction 484, which protrudes into the inner bore 412a has an inner diameter ID_C less than the desired full open bore diameter D of the tubing string and indentation 486 protrudes beyond the full open bore diameter of the tubing string. Constriction 484 can be removed by milling through the inner bore to open up the inner diameter ID_C at constriction to full bore. In so doing, access will be made to indentation 486, which will form an opening 486a through the sleeve where the indentation had protruded beyond diameter D. Milling axially through the inner diameter of the tubing string may be a desired step in any event to remove other ID obstructions such as seats 476.

[0100] Seals 488 may be positioned on sleeve 470 to provide seals against fluid leakage between the sleeve and body 412 between ports 482 and inner bore 412a.

[0101] Even if the sub does not include an isolation sleeve, a sleeve may be employed that is operable, as noted above to open production ports. For example, a production port may be positioned through the tubular body of the tool of FIG. 1, which is openable by removal of a portion of that tool's sleeve 14.

[0102] Sleeve 470 may be configured to be reclosable over ports 442 and/or 482. In particular, sleeve 470 may be moveable to overlie one or both of ports 442, 482. For example, in the illustrated embodiment, sleeve may include a profiled neck 496 formed for engagement by a pulling tool, such that the sleeve can be engaged by a tool and pulled up to reclose the ports. The position of the ports through the tubular body and seals on sleeve may be selected to permit closure and fluid sealing. If it is desired to later open the ports again, the isolator sleeve can be moved, as by use of a manipulator tool, back into a port-open position.

[0103] If desired, an inflow control device may be positioned to act on fluids passing through one or more of ports 442, 482. In one embodiment, an inflow control device, generally indicated as 482a, such as a screen or a choke, such as an ICD, can be provided to act on fluids passing through the production ports 482 and the sub can be configured such that flow from outer surface 412c to inner bore 412a can only be through production ports and the inflow control device installed therein.

[0104] If there are a plurality of sleeves along a length of a tubing string, the chokes may be selected to achieve a production profile. In particular, some chokes may allow greater flow than others to control the rate of production along a plurality of segments in the well.

[0105] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or “step for”.