MULTI-STAGE HYDRAULIC FRACTURING TOOL AND SYSTEM WITH RELEASABLE ENGAGEMENT

Abstract

The invention relates to a multi-stage hydraulic fracturing tool and system for controllably exposing selected locations along a wellbore to a pressurized fluid. The system includes a casing having one or more ports, one or more actuation members which travel down a borehole, and one or more sliding sleeves which initially cover some of the ports and are movable using a mating actuation member to uncover those ports. The system further includes a stop mechanism to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole under a first predefined amount of force, and a release mechanism to cause the actuation member to disengage from the sliding sleeve member release under a second predetermined amount of force.

Description

CROSS REFERENCE TO RELATED APPLICATION

This document claims the benefit under 35 U.S.C. § 119 of U.S. Provisional Patent Application No. 62/718,757, filed Aug. 14, 2018, which is hereby incorporated by reference in its entirety.

FIELD

The present invention pertains to the field of hydraulic fracturing in general and in particular to multi-stage hydraulic fracturing involving controlled exposure of selected locations along a wellbore to create multiple fracture treatments from a wellbore.

BACKGROUND

Hydraulic fracturing (“fracking”) and multi-stage hydraulic fracturing are methods used to increase the economic viability of the production of oil and gas wells. Hydraulic fracturing to extract oil and natural gas involves injecting pressurized fluid and proppant through the wellbore down to and into the reservoir that contains the hydrocarbons, in order to propagate fissures in the rock layers. By this process the fissures are filled with proppant, and become the paths by which the oil and gas flow out of the rock layers and into the wellbore system. Several methods of hydraulic fracturing have been utilized.

Multi-stage hydraulic fracturing methods typically require the use of multiple isolation members installed sequentially in the wellbore that allow for sequential isolation and treatment of intervals of the wellbore. Usually, the sequential isolation and fracturing of the wellbore is completed from the lower end to the upper end as this is traditionally considered to be the most operationally efficient and the lowest risk approach. Isolation members have included wireline set plugs, graduated balls, balls in a ‘counting’ or ‘ratcheting’ style systems, plugs that have geometric profiles on them that only will engage a unique location in the wellbore, coiled tubing run packers as well as others. Often sliding sleeves will also be employed together with the sequentially installed isolation members so that a sliding sleeve can be shifted into an open position which exposes ports through the casing to the reservoir which may be used as a conduit to place a fracture treatment into the reservoir from surface pumps.

The graduated ball activated sliding sleeve style of system as disclosed in U.S. Pat. No. 6,907,936 uses balls pumped from the surface as the isolation members. This method involves the sliding sleeve ball drop method which uses a graduated ball size functionality. This process involves first installing a production casing or liner having ports, which are covered with sliding sleeves. Each sleeve has a ball seat of a different and gradually larger diameter. To pump a fracture treatment, a ball is dropped into the wellbore and is pumped down to its corresponding size of ball seat where it lands and forms at least a partial seal. Pressure is increased in the upper portion of the wellbore above the seated ball until a shear member in the sleeve shears due to the pressure differential, causing the now free sliding sleeve to move deeper into the wellbore and exposing a now opened port between the wellbore and the reservoir. In this method, the ball and ball seat are the isolation member. The fracture treatment is then pumped through that port until completed, and the next larger ball is then dropped which will land and seal at the next shallowest stage. The process is repeated until all desired stages have been opened and fracked. Each fracturing stage is isolated from the one below it with a slightly larger ball. The system has a finite number of stages because the size of the balls eventually increases to a size that is too large to be pumped down the wellbore. The major drawback to this method is that the number of stages is limited by the diameter of the casing, which limits the number of balls used, and in turn the number of stages that can be fractured. Another drawback is that the ball seats are restrictions in the wellbore that will restrict well production or need to be milled out with coiled tubing increasing well costs.

Coiled tubing activated sliding sleeves use a packer and slips on the bottom hole assembly of coiled tubing to seal and engage on a sliding sleeve. The well is then pressured up which transmits a hydraulic force to the sliding sleeve shearing it open and exposing ports that a fracture placement may be pumped through. In this method the seals and slips on the bottom hole assembly act as the isolation member. The limitation of the method is that coiled tubing is required adding extra costs. Also, because coiled tubing is required, the lateral length that sleeves can be actuated is limited to as far as coiled tubing can reach. Coiled tubing cannot reach the same lateral lengths of casing as casing can be buoyed and or rotated to bottom increasing reach. The benefit of this type of method is that a substantially unlimited number of intervals may be fractured. Another benefit is that if a screenout is experienced during fracturing it can easily be cleared via circulation and the next uphole stage can be easily opened to regain connectivity to the reservoir.

Plug activated sliding sleeve systems, in which the plug and plug seal is the isolation member, involve first installing a casing or liner having ports which are covered with sliding sleeves. Each sliding sleeve has a particular profile which allows it to selectively engage with plugs having corresponding “matching” profiles. To pump a fracture treatment, a plug is dropped into the wellbore and is pumped down to its corresponding sliding sleeve where it mates, engages and at least partially forms a seal. Pressure is increased in the upper portion of the wellbore above the engaged plug until a shear member in the sleeve shears due to pressure differential. This causes the now free sliding sleeve to move deeper into the wellbore and exposes a now-opened port between the wellbore and the reservoir. The fracture treatment is then pumped through that port until completed. After this, another plug is pumped down the well which mates with the sliding sleeve at the next shallowest stage. The process is repeated until all desired stages have been opened and fractured. Each fracturing stage is isolated from the one below it with sequentially landed plug. This type of system may accommodate a greater number of stages than ball drop systems because there is significantly more freedom in creating different plug and sliding sleeve member profiles than there is in creating different ball diameters. As an example, 300 single point of entry fracture intervals can be obtained with this style of system.

A limitation with existing plug activated sliding sleeve systems is that the plug, once mated to the sliding sleeve, becomes a restriction in the wellbore. The plugs generally cannot be milled out economically because they are made from high strength steel. It is also not economical to retrieve them with coiled tubing or wireline because of the large number of runs in and out of the hole that would be required, as well as the horizontal reach limitations of coiled tubing and wireline. These restrictions lower well production when compared to a full bore well and can inhibit a full range of remedial wellbore operations such as refracturing. These systems also do not allow for immediate remediation of screenout events. If a screenout occurs and cannot be cleared by flowback, then coiled tubing must be run into the well to clear the screenout. Alternatively, perforating above the screened-out interval may be required to regain injectivity to the reservoir so that plugs can be pumped down. Another potential drawback with these systems is that they typically require a dissolving material to be present in the bore of the plug. Such materials can be costly to produce, representing a significant portion of the cost of the systems.

Therefore, there is a need for a system for multistage hydraulic fracturing that is not subject to one or more limitations of the prior art.

This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.

SUMMARY

In accordance with an aspect of the invention, there is provided a multi-stage hydraulic fracturing tool and system. In accordance with an embodiment of the present invention, there is provided a system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein, the casing defining an internal borehole extending longitudinally with the wellbore, the casing having one or more ports extending through the casing. The system comprises an actuation member configured for travelling down the borehole in a longitudinal direction; a first sliding sleeve member for disposal within the borehole and having an aperture for receiving the actuation member therein. The first sliding sleeve member is configured to initially cover one of the one or more ports, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port. The actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the sleeve member. A stopping member is affixed to the casing downhole of the sliding sleeve member. The stopping member is configured to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the sliding sleeve member. The stopping member is further configured to release under a second predetermined/defined amount of force to allow the further downhole travel of the sliding sleeve member. The first engagement portion and the second engagement portion are configured to release from one another upon the further downhole travel of the sliding sleeve member under the second predetermined amount of force, to cause the actuation member to disengage from the sliding sleeve member.

In accordance with another embodiment of the present invention, there is provided a system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein. The casing defining an internal borehole extending longitudinally with the wellbore, and the casing having one or more ports extending through the casing. The system comprises an actuation member configured for travelling down the borehole in a longitudinal direction and at least one sliding sleeve member for disposal within the borehole and each having an aperture for receiving the actuation member therein. The at least one sliding sleeve member configured to initially cover a respective port, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port. The actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the at least one sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the sleeve member. A stopping member is affixed to the casing downhole of more or more of the at least one sliding sleeve member, the stopping member is configured to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the sliding sleeve member. The stopping member is also configured to release under a second predetermined amount of force to allow the further downhole travel of the sliding sleeve member. The first engagement portion and the second engagement portion are configured to release from one another upon the further downhole travel of the sliding sleeve member under the second predetermined amount of force, to cause the actuation member to disengage from the sliding sleeve member.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages will become apparent from the following detailed description, taken in combination with the appended drawing, in which:

FIG. 1 illustrates, in a sectional view, a system in accordance with an embodiment of the present invention in a wellbore;

FIG. 2A illustrates, in a cross sectional view, an actuation member in accordance with an embodiment of the present invention;

FIG. 2B illustrates, in a cross sectional view, an actuation member in accordance with another embodiment of the present invention;

FIG. 2C illustrates, in a cross sectional view, an actuation member in accordance with another embodiment of the present invention;

FIG. 3 illustrates, in a cross sectional view, a sliding sleeve member in accordance with an embodiment of the present invention in a casing, for interoperation with the actuation member of FIG. 2A, 2B or 2C;

FIGS. 4A to 4B illustrate, in sectional views, operation of an actuation member with respect to the casing having a release mechanism in accordance with an embodiment of the present invention.

FIGS. 5A to 5J illustrate, in sectional views, operation of an actuation member with respect to the casing having a stopping member and a release mechanism in accordance with another embodiment of the present invention.

FIGS. 6A to 6I illustrate, in sectional views, operation of an actuation member with respect to the casing having a stopping member and a release mechanism in accordance with another embodiment of the present invention.

FIGS. 7A to 7H illustrate, in sectional views, operation of an actuation member with respect to the casing, in accordance with another embodiment of the present invention.

FIGS. 8A to 8I illustrate, in sectional views, operation of an actuation member having an optional stopping member, with respect to the casing, in accordance with another embodiment of the present invention.

FIGS. 9A to 9C illustrate, in sectional views, operation of an actuation member having an optional stopping member, with respect to the casing, in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention provide a system for controllably exposing selected locations along a wellbore to a pressurized fluid, wherein the wellbore includes an elongated casing disposed therein, which defines an internal borehole extending longitudinally with the wellbore, and the casing has one or more ports extending through the casing. The system includes a casing having one or more ports, one or more actuation members which travel down a borehole, and one or more sliding sleeves which initially cover some of the ports and are movable using a mating actuation member to uncover those ports. The system further comprises a release mechanism and a stopping mechanism downhole of the sliding sleeve member. The stopping mechanism is configured to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole under a first predetermined/predefined amount of force (e.g. due to hydraulic pressure) and initially inhibit further downhole travel of the sliding sleeve member. The stopping member is further configured to release (e.g. by breaking) under a second predetermined amount of force to allow the further downhole travel of the sliding sleeve member, and interact with the release mechanism to cause the actuation member to disengage from the sliding sleeve member.

In accordance with an embodiment, there is provided a system comprising casing having one or more ports, one or more actuation members which travel down a borehole, and one or more sliding sleeves which initially cover some of the ports (e.g. using shear pins) and are movable using a mating actuation member to uncover those ports. The one or more sleeves are configured to move downhole in response to a predetermined/predefined amount of force in the longitudinal direction to uncover the port. The actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the sleeve member.

Further provided is a stopping member affixed to the casing downhole of the sliding sleeve member, the stopping member configured to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the sliding sleeve member. The stopping member is configured to release under a second predetermined/predefined amount of force to allow the further downhole travel of the sliding sleeve member. The first engagement portion and the second engagement portion are further configured to release from one another upon the further downhole travel of the sliding sleeve member under the second predetermined amount of force, to cause the actuation member to disengage from the sliding sleeve member.

Once disengaged, an actuation member can be pumped further down the borehole.

Actuation members may also be referred to herein as plugs in the sense that they plug the borehole when engaged with a sliding sleeve. Embodiments of the present invention can be configured to release actuation members from sleeves.

In some embodiments, the first engagement portion of the actuation member comprises a wedged portion and a groove formed at least partially circumferentially around an outer surface of the actuation member, and the first engagement portion of the sliding sleeve comprises one or more inward-facing protrusions connected to the sliding sleeve member, and protruding radially into the aperture. One or both of the protrusions and the groove are configured, upon alignment of the protrusions and the groove, to move radially toward the other due to a biasing force so that the protrusions are received within the groove, whereupon the predetermined amount of force is transferred from the actuation member to the sleeve member.

In some embodiments, the groove can be instead formed on the sliding sleeve member and the mating protrusion can be formed on the actuation member. A variety of such releasable mating mechanisms can be provided.

In the embodiments involving the above-mentioned wedged portion, when the wedged portion is subjected to a force oriented opposite to the downhole direction (in which the actuation member is tending to travel), this force tends to push the part of the actuation member having the grooves (or protrusions) radially inward due to a levering action. This levering action can be used to facilitate the mating of actuation member and sliding sleeve member. Furthermore, this levering action can be used to facilitate the subsequent release of the actuation member from the sliding sleeve member.

In some embodiments, the wedged portion is located along a leading edge of the actuation member.

In some embodiments, the wedged portion protrudes from the outer surface of the actuation member at a location between a leading edge and a trailing edge of the actuation member.

In some embodiments, one or both of the actuation member and the sliding sleeve member have a resilient deformation region.

In some embodiments, the actuation member itself can be resiliently deformable in the radial inward direction. A portion of the actuation member which is resiliently deformable may also be referred to as a (resilient) deformation region.

In some embodiments, the actuation member has a deformation region comprising the groove disposed thereon; wherein the biasing force is generated by resilient radial inward deformation of the deformation region, the resilient radial inward deformation occurs in response to action of the wedged portion on the protrusions during downhole motion of the actuation member past the protrusions.

In some embodiments, the deformation region of the actuation member is the trailing portion of the actuation member. The deformation region of the actuation member may be colleted and includes the actuation member groove. Longitudinal cuts (collets) can be formed within a resilient material forming the (hollow) actuation member in order to allow the actuation member to be radially inwardly compressible in response to force imparted on the wedged portion by the protrusions (of the sliding sleeve member) when the actuation member moves downhole past the protrusions. It is noted that a variety of design options are available in which: a portion of the sliding sleeve member radially outwardly deforms while the actuation member remains undeformed; the actuation member radially inwardly deforms while the sliding sleeve member remains undeformed; or both the portion of the sliding sleeve member radially outwardly deforms and the actuation member radially inwardly deforms.

In some embodiments, downhole of the stopping member, the borehole or casing has a narrowing portion configured to contact and apply force on the wedged portion of the actuation member due to the further downhole travel. This force causes a second instance of radial inward deformation of the deformation region to release the protrusions from the groove, to cause the actuation member to disengage from the sliding sleeve member, thereby providing a release mechanism.

In some embodiments, downhole of the stopping member the casing comprises a protruding body configured to contact to and apply force on the wedged portion of the actuation member due to the further downhole travel. This force causes a second instance of radial inward deformation of the deformation region to release the protrusions from the groove, to cause the actuation member to disengage from the sliding sleeve member, thereby providing a release mechanism. In some embodiments, the protruding body is wedge shaped.

In some embodiments, the release mechanism comprises a wedge-shaped body configured to contact a wedged portion of an actuation member having grooves, and radially inwardly deform the wedged portion and a trailing portion as the actuation member moves downhole, the groove mounted on the trailing portion, thereby disengaging the groove from the protrusions of the sliding sleeve member.

In some embodiments, the system further comprises a second sliding sleeve member for disposal within the borehole uphole of the first sliding sleeve member. The second sliding sleeve member has a second aperture for receiving the actuation member therein. The second sliding sleeve member initially covers a second port of the one or more ports extending through the casing and configured, upon application of a second predetermined amount of force applied in the longitudinal direction, to move downhole in the longitudinal direction, thereby uncovering the second port. A second stopping member affixed to the casing downhole of the second sliding sleeve member. The second stopping member is configured to contact the second sliding sleeve member after the sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the second sliding sleeve member. The second stopping member is further configured to release under another predetermined/predefined amount of force to allow the further downhole travel of the sliding sleeve member. The second sliding sleeve member comprises an engagement portion configured to matingly engage the first engagement portion of the actuation member, to allow for the predetermined amount of force to be transferred from the actuation member to the sleeve member. The first engagement portion and the engagement portion of the second sleeve are configured to release from one another upon the further downhole travel of the sliding sleeve member under the second predetermined amount of force, to cause the actuation member to disengage from the sliding sleeve member.

The system further comprises one or more second inward-facing protrusions connected to the second sliding sleeve member, wherein the second protrusions at least initially protrude radially into the second aperture, wherein the second protrusions has a second further length in the longitudinal direction, and the second further length is less than or equal to the further length. One or both of the second protrusions and the second groove is configured, upon alignment of the second protrusions and the second groove, to move radially toward the other due to a biasing force so that the second protrusions are received within the second groove, whereupon the predetermined amount of force is transferred from the second actuation member to the second sleeve member. The one or both of the second actuation member and the second sliding sleeve have a second deformation region, wherein the second deformation region of the second sliding sleeve has the one or more inward facing protrusions, wherein the biasing force is generated by one or both of: resilient radial outward deformation of the second deformation region of the second sliding sleeve member, and resilient radial inward deformation of the second actuation member, the resilient radial outward and inward deformation occurring in response to action of the second wedged portion on the second protrusions during downhole motion of the second actuation member past the second protrusions.

In some embodiments, the actuation member initially is configured to substantially fill the borehole and travels down the borehole in response to hydraulic pressure applied uphole of the actuation member.

In some embodiments, actuation member includes a longitudinal aperture extending from an uphole face of the actuation member to a downhole face of the actuation member, and a plug member seat within the longitudinal aperture, the plug member seat configured for receiving and retaining a plug member for blocking the longitudinal aperture. In some embodiments, the plug member is controllably dissolvable.

In some embodiments, the actuation member includes a leading portion and a trailing portion, wherein the leading portion located downhole of the trailing portion. The trailing portion is compressible radially inwardly due to force applied by the one or more inward-facing protrusions on the wedged portion when the actuation member moves downhole past the one or more inward-facing protrusions of a sleeve.

In some embodiments, the trailing portion comprises resiliently deformable collets actuated for radially inward compression.

In some embodiments, the actuation member includes a longitudinal aperture extending from an uphole face of the actuation member to a downhole face of the actuation member, and wherein the leading portion comprises a plug member seat within the longitudinal aperture, the plug member seat configured for receiving and retaining a plug member for blocking the longitudinal aperture and receiving a downhole hydraulic force for propelling the actuation member.

In another aspect, the system of the present invention comprises an actuation member configured for travelling down the borehole in a longitudinal direction; one or more sliding sleeve members for disposal within the borehole, and each having an aperture for receiving the actuation member therein. The one or more sliding sleeve members are configured to initially cover a respective port, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port. The actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the one or more sliding sleeve members to allow for the predetermined/predefined amount of force to be transferred from the actuation member to the sleeve member. The system is further provided with a stopping member affixed to the casing downhole of one or more of the at least one sliding sleeve member. The stopping member is configured to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the sliding sleeve member. The stopping member is further configured to release under a second predetermined amount of force to allow the further downhole travel of the sliding sleeve member. The first engagement portion and the second engagement portion are configured to release from one another upon the further downhole travel of the sliding sleeve member under the second predetermined amount of force, to cause the actuation member to disengage from the sliding sleeve member.

In some embodiments, the stopping member is affixed to the casing downhole of each of the at least one sliding sleeve member.

In some embodiments, the system further comprises at least one additional actuation member, wherein the at least one additional actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the at least one sliding sleeve member, which is different than the sliding sleeve member engaged with the first actuation member. This configuration can be achieve by providing different mating structures and/or by difference in outer diameter of the additional actuation members as discussed elsewhere herein.

In some embodiments, the stopping members and release mechanisms are included with only some of the sliding sleeve members.

The combination of the stopping member, and the releasable mating mechanism operates as follows. Following engagement of the actuation member and the sliding sleeve member, the sliding sleeve member is pushed downhole until it abuts a frangible stopping mechanism (stopping member), such as a shear pin or shear ring. The stopping mechanism is breakable under a predetermined amount of force in the downhole direction, this force being greater than the amount of force due to hydraulic pressure applied when initially moving the sliding sleeve member to uncover the port. When release of the actuation member is desired, this amount of force can be applied by increased hydraulic pressure, optionally following a blocking of the port (and other uphole ports). This hydraulic pressure presses on the actuation member, which in turn presses on the sliding sleeve member, which further in turn presses on the stopping mechanism, causing it to break or release. The sliding sleeve member and actuation member then travel further downhole a limited distance, until the actuation member's wedged portion encounters a radially inwardly (possibly angled) protruding body affixed to the borehole perimeter. This encounter causes the levering action as discussed above, which disengages the actuation member's groove (or protrusions) from the sliding sleeve member's protrusions (or groove). This causes the actuation member to release from the sliding sleeve member so that it can continue to be pushed downhole away from the sliding sleeve member.

Increasing hydraulic pressure can be assisted by re-blocking the ports, either with balls, or an intentional or unintentional screenout event, or a port not accepting fluid for whatever reason.

The stopping member can comprise a shear mechanism, such as a shear pin, a plurality of shear pins, or a shear ring, configured to break under a predetermined pressure.

The inclusion of a release mechanism allows a single actuation member to engage with and move multiple sliding sleeve members. As explained elsewhere herein, the actuation member only engages with and moves sliding sleeve members which have protrusions of the appropriate dimensions (e.g. length) to fit within the actuation member's groove. However, multiple such sliding sleeve members can be included within the borehole and the actuation member can sequentially engage with and actuate each sliding sleeve member as the actuation member moves downhole. Each of these multiple sliding sleeve members, except optionally the sliding sleeve member furthest downhole, is associated with a release mechanism.

In some embodiments, the actuation member is configured to selectively engage with the sliding sleeve member and one or more first further sliding sleeve members disposed within the borehole, and to pass without engagement through one or more second further sliding sleeve members, disposed within the borehole. The first further sliding sleeve members and the second sliding sleeve members are configured to initially cover respective ones of the ports and move downhole to uncover the respective ones of the ports.

In some embodiments, the system further comprises a second actuation member configured for travelling down the borehole in the longitudinal direction, wherein the second actuation member includes a second wedged portion and a second groove formed at least partially circumferentially around an outer surface of the second actuation member. The second groove has a further length in the longitudinal direction, wherein the second actuation member has an outer diameter that is smaller, by a predetermined factor, than a diameter of the aperture of the sliding sleeve member. The predetermined factor is sufficiently large to inhibit the protrusions from being retained within the second groove during downhole motion of the second actuation member past the sliding sleeve member.

In some embodiments, an anti-rotation mechanism, such as a pin-and-groove mechanism, is provided between the sliding sleeve member and the casing. The anti-rotation mechanism inhibits rotation of the sliding sleeve member. This may be useful for example when the sliding sleeve member or aperture thereof is being milled out.

In some embodiments, a C-ring or other one-way-motion or locking mechanism is provided with the sliding sleeve member and configured to retain the sliding sleeve member in the downhole (open) position once the sliding sleeve member has been moved so as to uncover the ports.

Embodiments of the present invention can utilize two or more families of tools in the same wellbore. A tool refers to a sliding sleeve member or actuation member, and a family of tools refers to a set of actuation members and sliding sleeve members, such that the actuation members are capable of engaging with and moving the sliding sleeve members, provided that the grooves and protrusions are of mating size. For further clarity, even if the protrusions and grooves of a sliding sleeve member and an actuation member, respectively, are mismatched such that engagement is inhibited, the sliding sleeve member and actuation member are still considered part of the same family if this is the only feature inhibiting the engagement.

As an example, a first family of tools can include sliding sleeve members whose aperture is of a first diameter, and actuation members sized to approximately the same first diameter, while a second family of tools can include sliding sleeve members whose aperture is of a second diameter (smaller than the first diameter), and actuation members sized to approximately the same second diameter. Sliding sleeve members within each family can have different lengths of protrusions, and actuation members within each family can have different lengths of grooves. Sliding sleeve members belonging to the second family can be located downhole from sliding sleeve members belonging to the first family. Actuation members belonging to the second family can then travel downhole past all sliding sleeve members belonging to the first family, even if the grooves of these actuation members are the same length or longer than the protrusions of one or more sliding sleeve members of the first family. The ability of the actuation members in the second family to avoid capture by sliding sleeve members of the first family is due to the mismatch in diameters.

The use of multiple families can allow further diversity in the sliding sleeve members, so that the stage count within the wellbore (i.e. the number of sliding sleeve members and ports) be increased.

Embodiments of the present invention provide for a multi-stage hydraulic fracturing completions system that allows for sequential and/or staggered (e.g. leapfrogged) treatment of wellbore intervals. This may be achieved while avoiding obstruction of productive length of the wellbore with actuation members, plugs or balls after the treatments at each stage are completed. Embodiments of the present invention may achieve this while also maintaining a substantially unencumbered production pathway. This may be facilitated by the controllable release of actuation members from mated sliding sleeve members.

Embodiments of the present invention can provide for the automatic release of actuation members in the event of a screenout event, to clear the proppant from the wellbore and move completion operations to the next stage without the need for coiled tubing, wireline or perforating guns to perforate the well casing to regain reservoir injectivity. This releasing action will open up the wellbore below the (now released) actuation member to hydraulic pressure from surface, thus allowing pumping operations to continue. This can allow the treatment fluids to continue to be injected into the intervals below the screened out zone.

Embodiments of the present invention can also allow for the release of actuation members in the event of an interval of the reservoir being unable to accept treatment fluid at a desirable rate. This can again facilitate continuation of the completion operations without the need for coiled tubing, wireline or perforating guns to perforate the well casing and establish a new injectivity point to the reservoir.

Embodiments of the present invention can be applied for screenout remediation or untreatable sections of a reservoir.

Embodiments of the present invention aim to increase efficiency of multistage hydraulic fracturing operations by providing a method for actuation members (plugs) in actuation member-activated sliding sleeve systems to be released from their mated sliding sleeves after fracturing placement at the corresponding interval is complete. A released actuation member can then be displaced to a lower portion of the wellbore (e.g. a storage rathole) where it will remain, and where it will not interfere with further operations.

Embodiments of the present invention may be used to purposefully create screenout events. Some reservoirs are observed to have better production when they are screened out.

Embodiments of the present invention may be employed to provide a method of leapfrog fracturing, also known as staggered fracturing. Leapfrog fracturing is a method of non-sequential fracturing that is believed to increase the productivity from fracture treatments in certain type of reservoirs. Leapfrog fracturing can be described as a method in which a lowermost stage is fractured, a stage more shallow then the next shallowest stage is fractured and then one or more stages between these two fractured stages are fractured. Embodiments of the present invention provide a method and system for leapfrog fracturing without the use of coiled tubing and which may potentially be performed as efficiently as other current fracturing methods. In one embodiment, leapfrog fracturing comprises fracturing the well in the following sequence; deepest stage, third deepest stage, second deepest stage, fourth deepest stage, sixth deepest stage, fifth deepest stage, etc.

In some embodiments, in the leapfrog fracturing, an actuation member can be used to uncover a first one of a plurality of ports by interoperating with a corresponding first sliding sleeve member. The actuation member can then be released from the first sliding sleeve member as described above and moved downhole. The same actuation member or a different actuation member can then be used to uncover a second one of a plurality of ports by interoperating with a corresponding second sliding sleeve member. This second port is non-adjacent to the first port, in the sense that one or more further ports are located along the borehole between the first port and the second port. These further ports can be subsequently uncovered, or previously uncovered.

In the following paragraphs, embodiments will be described in detail by way of example with reference to the accompanying drawings, which are not drawn to scale, and the illustrated components are not necessarily drawn proportionately to one another. Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than as limitations of the present disclosure.

FIG. 1 illustrates a wellbore 110 and a casing 112 (not showing the stopping member and the release mechanism) included in the wellbore, and having a plurality of ports 114 located along the length of the casing. An actuation member 116 according to the present invention is pieced within a borehole 118 which is defined by the inner sidewalls of the casing, and travels (under hydraulic pressure) through the borehole in the downhole direction. Multiple sliding sleeve members 120 according to the present invention are shown which initially cover the various ports 114. The sliding sleeve members include protrusions 122 of varying lengths, and the actuation member 116 includes a groove 124 (radial keyway) of a given length. The actuation member 116 travels down the borehole until it reaches a sliding sleeve member 120 having protrusions 122 which are equal to or shorter in (longitudinal) length than the corresponding groove in the actuation member. At this point the protrusions matingly fit within the groove 124 of the actuation member 116, This mating allows downhole force to be applied to the sliding sleeve member in order to move it downhole, thereby uncovering the associated ports.

Alternatively, the grooves may be disposed on the sliding sleeve members and the corresponding protrusions may be disposed on the actuation members. Other keyed systems which allow for actuation members to selectively engage with particular sliding sleeve members may also be employed.

The casing can be viewed as a structure within the wellbore which is relatively impermeable to hydraulic fracking fluid. The casing can be formed of one or more mating sections of selected materials.

FIGS. 2A, 2B and 2C illustrate, in cross-sectional view, embodiments of actuation member 200 a/b/c (before being placed in the casing), and FIG. 3 illustrates a part of a casing 370 and a sliding sleeve member 340, provided in accordance with an embodiment of the present invention. The actuation member 200a/b/c, the casing 370 and the sliding sleeve member 340 are typically of generally cylindrical shape and are located, in operation, within a wellbore. One or more ports are located at various locations along the length of the casing, which provide for fluidic communication between the borehole defined by the casing and the sidewalls of the wellbore. The fluidic communication via an exposed port facilitates hydraulic fracturing operations, in which fracking fluid is pumped downhole through the borehole and out of the exposed ports. Each of the sliding sleeve members is placed within the borehole and initially covers one or more of the ports and is movable, using a mating actuation member, so as to selectably uncover these ports. The actuation member is configured for travelling down the borehole in a longitudinal direction and has an uphole end portion 202a/b/c and a downhole portion 204a/b/c.

The outer face of the actuation member 200 a/b/c includes a wedged portion 220a/b/c towards downhole end portion 204a/b/c. The wedged portion 220a/b/c can be frusto-conical in shape. A groove 225a/b/c is formed at least partially circumferentially around an outer face of the actuation member 200a/b/c. The groove has a first length 227a/b/c in the longitudinal direction 201. The groove 225 a/b/c includes a radially oriented face 229a/b/c which is located at the uphole end of the groove. The face 229a/b/c may be, but is not necessarily radially oriented at right angles to the longitudinal direction 201. The face 229 a/b may be oriented at an acute angle to the longitudinal direction 201 (that is, toward the downhole and in the direction of travel of the actuation member). The acute angle can be an 89 degree angle, an 85 degree angle, or another angle, e.g. smaller than 89 degrees, or between 85 degrees and 90 degrees. In another embodiment, the acute angle can be 50 degrees, or 45 to 55 degrees, or another angle, e.g. between 40 and 90 degrees. The angle and size of the face 229a/b/c is selected so that, upon engagement with a protrusion of the sliding sleeve member 340 (as described below), the protrusion will remain engaged in the groove 225a/b/c (and with the face 229a/b/c). The protrusion 359 of the corresponding sliding sleeve has a similarly sized and angled mating face.

The configuration of the actuation member for travelling down the borehole in a longitudinal direction includes sizing and shaping the actuation member to closely match the borehole of the casing (such as the actuation member of FIG. 2A). Some variation in diameter may be allowed in the case that different families of actuation members are provided.

Alternatively the configuration of the actuation member includes providing an actuation member with a longitudinal aperture 215 extending from an uphole face of the actuation member to a downhole face of the actuation member, and a plug member seat 110 within the longitudinal aperture, and placing of a plug member 205 (such as a ball) into a the plug member seat 210. The plug member 205 blocks a longitudinal aperture 215 of the actuator member which, when unblocked, allows fluidic communication between an uphole end 102 of the actuation member and a downhole end 204 of the actuation member (for example actuation members of FIGS. 2B and 2C).

Hydraulic fluid is applied under pressure uphole of the actuation member. Due to its slidability within the borehole and its size, shape and/or blocked longitudinal aperture, the actuation member is motivated to move downhole under the hydraulic fluid pressure. In some embodiments, the plug member is dissolvable or otherwise removable. This provides the capability to unblock the borehole after the actuation member has engaged with and operated a sliding sleeve member to open a port in the borehole sidewall.

In some embodiments the wedged portion is provided along a leading edge of the actuation member proximate to the downhole end (FIG. 2c). The wedged portion can be frustro-conical in shape and, in the embodiment illustrated in FIG. 4c, extends from the outer edge of the aperture 215c to a largest outer diameter of the actuation member.

As depicted in FIG. 3, the sliding sleeve member 340 includes an aperture 342 for receiving the actuation member therein. For example, the sliding sleeve member can be generally shaped as a hollow cylinder. The aperture has a diameter which is approximately the same or incrementally larger than the overall largest diameter of the actuation member, such as 200a, 200b or 200c, so that the actuation member can enter and potentially pass through the aperture 242.

The sliding sleeve member 340 initially covers a port 345 in the borehole. The port can extend partially or fully around the circumference of the casing, and multiple such ports may be provided. The sliding sleeve member 340 can be fixed in place using shear pins 350 or another frangible or disengagable securing member. Once the shear pins 350 have been broken due to application of force in the longitudinal direction, the sliding sleeve member 340 is slidable within the borehole. As such, the sliding sleeve member 340 is configured, upon application of force in the longitudinal direction 301, to move downhole in the longitudinal direction, thereby uncovering the port 345. The shear pins may be rated to break under application of a rated amount of force, and hence the sliding sleeve member may be configured to move only in response to a predetermined amount of force which is at least the rated amount of force.

In some embodiments, a seal may be provided between the sliding sleeve member 340 and the casing 370. The seal is configured to seal/isolate the port 345 when the sliding sleeve member is in the closed position.

The sliding sleeve member 340 includes a deformation region and one or more inward-facing protrusions 355 connected to the sliding sleeve member in the deformation region. The protrusions 355 are biased to protrude radially into the aperture 342 so as to contact the wedged portion 320 during travel of the actuation member 200 past the protrusions 355. The protrusions 355 are movable radially outward by the wedged portion 320 of the actuation member 200 when the actuation member moves downhole past the protrusions 355.

In the presently illustrated embodiment, the deformation region of the sliding sleeve member 340 is defined by longitudinal extensions 360 extending towards downhole, wherein the protrusions 355 are located at or near ends of longitudinal extensions 360. The extensions 360 may be viewed as cantilever springs upon which the protrusions 355 are mounted. The cantilever springs are formed of a resilient material, such as metal, which applies inward biasing force to the protrusions in response to being pushed outward by the wedged portion 320 of the actuating member 200. The cantilever springs can refer to elongated, resiliently flexible bodies anchored at one end. It is noted that the borehole includes a cavity 365 which surrounds a portion of the sliding sleeve member in the vicinity of the protrusions 355. This cavity 365 provides space for outward motion of the protrusions 355 (and portions of the extensions 360). The extensions 360 can be formed by creating longitudinal cuts 357 in the cylindrical body of the sliding sleeve member 340, the cuts extending to a downhole edge 359 of the cylindrical body. The cuts also extend through an inwardly-projecting (full or partial) annulus from which the protrusions 355 are formed. Strain relief 358 can also be included to facilitate flexing of the extensions 360 as cantilever springs.

Alternative structures for holding and inwardly biasing the protrusions 355 can also be used. For example, the cuts 357 are not necessarily longitudinal and do not necessarily extend to the downhole edge 359. The cuts pass through a deformation region of the sliding sleeve member, the deformation region including the inward-facing protrusions 355 formed on an interior face of the sliding sleeve member hollow tube. Resilient material (e.g. spring steel) in the deformation region provides inward bias to the protrusions, and the cuts allow radial outward movement of the protrusions due to the wedged portion 320. Again, the borehole includes the cavity 365 to allow the radial outward movement of the protrusions. In another embodiment, the protrusions are movably housed in a cartridge placed in a hole of the sliding sleeve. The protrusions move radially, and are biased inwardly for example using coil springs, hydraulic fluid or another mechanism.

The protrusions 355 have a second length 356 in the longitudinal direction 301. In the presently illustrated case, the second length is less than or equal to the first length 327 of the groove 325 in the actuation member 200. As such, the protrusions 355 are configured, upon alignment with the groove 325 of the actuation member, to move radially inward due to the biasing force applied on the protrusions (the biasing force being generated in response to deformation of the resilient deformation region by travel of the wedged portion of the actuation member). Upon such radial inward motion, the protrusions 355 are received within the groove 325 of the actuation member 200. The protrusions and the groove are configured so that, once received, the protrusions are retained within the groove substantially without slippage that would cause the protrusions to fall out of the groove. This action is referred to as a keying action, in which only actuation members having a sufficiently long groove allow for protrusions of a given (same or shorter) length to be received in the groove.

Upon retention of the protrusions 355 within the groove 325, the radially oriented face 329 of the groove matingly engages respective radially oriented faces 359 of each of the protrusions 355. This engagement allows a transfer of the predetermined amount of force (required to slide the sliding sleeve) from the actuation member to the sleeve member. In more detail, hydraulic pressure imparts the predetermined amount of force onto the actuation member, the force is transferred via the mating faces 329, 359 onto the protrusions, and, by virtue of connection of the protrusions with the sliding sleeve member 340, the force causes shearing of the shear pins 350 and sliding of the sliding sleeve member. In some embodiments, the predetermined amount of force is at least equal to the rated shearing force of the shear pins.

It is noted that, if the second length 356 of the protrusions were greater than the first length 327 of the groove, then the protrusions would be too long to fit within the groove. In this case, the actuation member would pass through the sliding sleeve without the protrusions being received in the groove. This feature can be used to selectably pass the actuation member through other sliding sleeve members (having protrusions which are longer than the first length 327), upstream of the illustrated sliding sleeve member. This feature can also be used to selectably pass another actuation member (having a groove which is shorter than the second length 356) through the illustrated sliding sleeve member, and toward other sliding sleeve members downstream of the illustrated sliding sleeve member. A plurality of sliding sleeve members and actuation members can be provided and used within the borehole, in which different sliding sleeve members have differently-lengthed protrusions, and different actuation members have differently-lengthed grooves.

The inner diameter of the wedged portion may be smaller than the diameter defined by the inner edges of the protrusions 355, so as to reduce shock when the wedged portion contacts the protrusions.

The depth of the groove is generally sufficient for holding at least part of the protrusions 355 without slippage, over-stressing of the springs, etc.

In some embodiments, rather than or in addition to providing a resilient deformation region of the sliding sleeve member (which allows the protrusions on the sliding sleeve member to be pushed outward by the wedged portion of the actuation member), the actuation member itself can be resiliently deformable in the radial inward direction. A portion of the actuation member which is resiliently deformable may also be referred to as a (resilient) deformation region. In some embodiments, the deformation region of the actuation member is the trailing portion of the actuation member. The deformation region of the actuation member may be colleted and includes the actuation member groove. Longitudinal cuts (collets) can be formed within a resilient material forming the (hollow) actuation member in order to allow the actuation member to be radially inwardly compressible in response to force imparted on the wedged portion by the protrusions (of the sliding sleeve member) when the actuation member moves downhole past the protrusions. It is noted that a variety of design options are available in which: a portion of the sliding sleeve member radially outwardly deforms while the actuation member remains undeformed; the actuation member radially inwardly deforms while the sliding sleeve member remains undeformed; or both the portion of the sliding sleeve member radially outwardly deforms and the actuation member radially inwardly deforms.

FIGS. 4A and 4B illustrate, in cross-section, an exemplary release mechanism 410 in the form of a wedge-shaped body engaging with an exemplary actuation member 420 (having groove(s)) to cause the actuation member to disengage from an exemplary sliding sleeve member 430 (having protrusion(s)) after the actuation member 420 has received the sliding sleeve member's protrusions 436 within the actuation member's grooves 426, and after the actuation member has moved the sliding sleeve member downhole. FIG. 4D shows the sliding sleeve member having moved downhole from its position in FIG. 4C, thus uncovering the port. When the sliding sleeve member 430 moves toward its open position, the actuation member 420, correspondingly moves downhole, thus encountering the wedge-shaped body 410 protruding inward into the borehole. The wedge-shaped body 410 of the release mechanism is tapered toward (i.e. narrows in) the downhole direction. In some embodiments, the wedge-shaped body 410 can be an annulus with an inner surface which is tapered toward the downhole direction. In some embodiments, one or more portions of the annulus can be omitted. The release mechanism can alternatively be non-tapered and non-wedge-shaped. For example the release mechanism can protrude radially inward with an uphole face that is perpendicular to the downhole direction.

As the actuation member 420 moves downhole, the wedge-shaped body 410 interferes with the wedged portion 422 of the actuation member, as described elsewhere herein. The wedged portion 422 is integrated with an inwardly deformable portion 424 of the actuation member 410. As the deformable portion of the actuation member 420 is more deformable than the wedge-shaped body 410, this part of the actuation member is deformed radially inward as the actuation member moves downhole, as shown in FIG. 4D. The grooves 426 of the actuation member 420 are also mounted on the inwardly deformable portion 424 and consequently are pushed radially inward. This causes the grooves 426 to disengage from the protrusions 436 of the sliding sleeve member. The consequence of this deformation is that the actuation member 420 releases from the sliding sleeve member 430 and is then able to travel downhole where it may potentially encounter other mating and/or non-mating sliding sleeve members. As such, a levering action is performed which releases the actuation member. The consequence of the levering action, radially inward deformation of the actuation member and its release is shown in FIG. 4E

FIGS. 5A to 5J illustrate operation of a system comprising a stopping member along with the release mechanism. In FIG. 5A, the sliding sleeve member 530 initially covers the ports 516. In FIG. 5B, the actuation member enters the aperture of the sliding sleeve member and approaches the protrusions 536 under a first predetermined amount of force/pressure. In FIG. 5C, the protrusions 536 of the sliding sleeve member have engaged the groove 526 of the actuation member, the protrusions having been pressed into the groove due to the biasing force. In FIG. 5D, the locked actuation member and the sliding sleeve has moved further downhole to the opening position thereby opening the ports 516, and leading edge 514 of sleeve resting on the stopping member(s) 512, 518. The stopping members inhibit (at least initially) further downhole motion of the sliding sleeve member and actuation member locked thereto. This keeps the wedged portion of the actuation member from contacting the release mechanism 510.

In FIGS. 5E and 5F balls have been used to block the opened ports 516, which results in or otherwise facilitates increasing the pressure to a second predetermined amount, which would disengage the stopping member 514. In more detail, because the ports are blocked, hydraulic pressure on the actuation member increases, or is easier to increase because hydraulic fluid can no longer exit the ports. This increased pressure on the actuation member causes increased force on the stopping member, which is designed to break or otherwise disengage under a predetermined force, such as the increased force. As already mentioned, the stopping member can be a shear pin or shear ring.

FIGS. 5G and 5H show disengagement of the stopping member to allow further downhole movement of the actuation member and its interaction with the release mechanism 510, to release the actuation member 520 from the sliding sleeve member 530. (The release of the actuation member is via the mechanism or levering action as discussed further, for example with respect to FIGS. 4A and 4B.) The actuation member is then able to travel downhole where it may potentially encounter other mating and/or non-mating sliding sleeve members, and eventually be expelled out of the system or held in an end reservoir of the borehole. The release mechanism can be unanchored and also travel downhole, or anchored on a track, tether, etc.

FIGS. 6A to 6I illustrate operation of a system comprising a stopping member along with the release mechanism same as described in FIGS. 5a to 5J, with the difference that in this embodiment, interval screenout event(s) provide the increase in pressure for disengagement of the stopping member. The screenout event is shown in FIG. 6E, where a “T” shaped body blocking the ports represents a screenout event, for example in which granular material has clogged the ports. The screenout events may be intentional or unintentional.

FIGS. 7A to 7H illustrate operation of a system comprising a stopping member along with the release mechanism same as described in FIGS. 5A to 5J, with the difference that in this embodiment, failure of port(s) to accept hydraulic fluid provides the increase in pressure for disengagement of the stopping member. Although the ports are shown as unblocked, hydraulic fluid is inhibited from exiting via the ports, or can only exit to a limited amount. Automatic release under such circumstances can be beneficial in moving the fracturing operations onward to a further stage.

FIGS. 8A to 8I illustrate a non-sequential (leap frog) fracking system operation. In FIG. 8A, an actuation member 860 begins travelling downhole, and all sliding sleeve members 815, 825, 835, 845 are in the closed (port-covering) position. In FIG. 8B, the actuation member 860 has engaged with the sliding sleeve member 835, and moved the sliding sleeve member 835 to the open position, wherein ports 836 are opened, and a leading edge of the sleeve member 835 is resting on the stopping member 832. In FIG. 8C “drop balls” 862 being travelling downhole to close the opened ports and to increase the pressure in the system. In FIG. 8D, the ports 836 have been closed with the balls 862 and the actuation member has been disengaged due to shearing of the stopping member 832 by increased pressure, and the action of the release mechanism 830, and is now engaged with the sliding sleeve member 845. In FIG. 8D, the actuation member 860 has moved the sliding sleeve member 845 to the open position, thereby opening ports 846, and a second actuation member 864 begins travelling downhole.

In FIG. 8E the second actuation member 864 is travelling further downhole towards sliding sleeve 825, after engaging and moving the sliding sleeve 815 to open position and opening ports 816 for fracking, when the leading edge of the sliding sleeve was engaged with the stopping member 812 under a predetermined pressure, and now being released due to increase in pressure achieved by closing the ports 816 with drop balls 866.

In FIG. 8F the second actuation member 864 has engaged with the sliding sleeve member 825, and moved the sliding sleeve member 825 to the open position, wherein ports 826 are opened, and a leading edge of the sleeve member 835 is resting on the stopping member 822 under another predetermined pressure conditions.

In FIG. 8G “drop balls” 868 travelling downhole to close the opened ports 826 and to increase the pressure in the system to another predetermined level.

In FIG. 8H, the ports 826 have been closed with the balls 868 and the actuation member 864 has been disengaged due to shearing of the stopping member 822 by increased pressure, and the action of the release mechanism 820, and is now being expelled from the system.

In FIG. 8I the various drop balls have been cleared from the system.

As such two actuation members have been used to achieve non-sequential opening of ports.

FIGS. 9A to 9C illustrate alternative embodiments wherein the actuation member can be configured to hold a plug member 905 (such as a ball) into a corresponding (e.g. tapered) plug member seat 910 of the actuation member. The plug member 905 blocks a longitudinal aperture 915 of the actuator member which, when unblocked, allows fluidic communication between an uphole end 902 of the actuation member and a downhole end 904 of the actuation member.

As used herein, the “present disclosure” or “present invention” refers to any one of the embodiments described herein, and any equivalents. Furthermore, reference to various aspects of the invention throughout this document does not mean that all claimed embodiments or methods must include the referenced aspects or features.

It should be understood that any of the foregoing configurations and specialized components or may be interchangeably used with any of the apparatus or systems of the preceding embodiments. Although illustrative embodiments are described hereinabove, it will be evident to one skilled in the art that various changes and modifications may be made therein without departing from the scope of the disclosure. It is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the disclosure.

Although embodiments of the invention have been described above, it is not limited thereto and it will be apparent to those skilled in the art that numerous modifications form part of the present invention insofar as they do not depart from the spirit, nature and scope of the claimed and described invention.

Claims

1. A system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein, the casing defining an internal borehole extending longitudinally with the wellbore, the casing having one or more ports extending through the casing, the system comprising:

an actuation member configured for travelling down the borehole in a longitudinal direction;

a first sliding sleeve member for disposal within the borehole and having an aperture for receiving the actuation member therein, the first sliding sleeve member configured to initially cover one of the one or more ports, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port;

wherein the actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the first sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the first sliding sleeve member; and

a stopping member affixed to the casing downhole of the first sliding sleeve member, the stopping member configured to contact the first sliding sleeve member after the first sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the first sliding sleeve member, the stopping member configured to release under a second predetermined amount of force to allow said further downhole travel of the first sliding sleeve member;

wherein the first engagement portion and the second engagement portion are configured to release from one another upon said further downhole travel of the first sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the first sliding sleeve member.

2. The system of claim 1, wherein the first engagement portion of the actuation member comprises a wedged portion and a groove formed at least partially circumferentially around an outer surface of the actuation member, and

the first engagement portion of the first sliding sleeve member comprises one or more inward-facing protrusions connected to the first sliding sleeve member, and protruding radially into the aperture, one or both of the protrusions and the groove configured, upon alignment of the protrusions and the groove, to move radially toward the other due to a biasing force so that the protrusions are received within the groove, whereupon the predetermined amount of force is transferred from the actuation member to the first sliding sleeve member.

3. The system of claim 2, wherein one or both of the actuation member and the first sliding sleeve member have a deformation region.

4. The system of claim 2, wherein the actuation member has a deformation region comprising the groove disposed thereon; wherein the biasing force is generated by resilient radial inward deformation of the deformation region, said resilient radial inward deformation occurring in response to action of the wedged portion on the inward-facing protrusions during downhole motion of the actuation member past the inward-facing protrusions.

5. The system of claim 3, wherein downhole of the stopping member, the borehole or casing has a narrowing portion configured to contact and apply force on the wedged portion of the actuation member due to said further downhole travel, said force causing a second instance of radial inward deformation of the deformation region to release the inward-facing protrusions from the groove, to cause the actuation member to disengage from the first sliding sleeve member.

6. The system of claim 3, wherein downhole of the stopping member the casing comprises a wedge-shaped body configured to contact to and apply force on the wedged portion of the actuation member due to said further downhole travel, said force causing a second instance of radial inward deformation of the deformation region to release the inward-facing protrusions from the groove, to cause the actuation member to disengage from the first sliding sleeve member.

7. The system claim 1, further comprising:

a second sliding sleeve member for disposal within the borehole uphole of the first sliding sleeve member, the second sliding sleeve member having a second aperture for receiving the actuation member therein, the second sliding sleeve member initially covering a second port of the one or more ports extending through the casing and configured, upon application of a second predetermined amount of force applied in the longitudinal direction, to move downhole in the longitudinal direction, thereby uncovering the second port;

a second stopping member affixed to the casing downhole of the second sliding sleeve member, the second stopping member configured to contact the second sliding sleeve member after the second sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the second sliding sleeve member, the second stopping member configured to release under another predetermined amount of force to allow said further downhole travel of the second sliding sleeve member;

wherein the second sliding sleeve member comprises an engagement portion configured to matingly engage the first engagement portion of the actuation member, to allow for the predetermined amount of force to be transferred from the actuation member to the second sliding sleeve member;

wherein the first engagement portion and the engagement portion of the second sliding sleeve member are configured to release from one another upon said further downhole travel of the second sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the second sliding sleeve member.

8. The system of claim 2, wherein the wedged portion is located along a leading edge of the actuation member.

9. The system of claim 2, wherein the wedged portion protrudes from the outer surface of the actuation member at a location between a leading edge and a trailing edge of the actuation member.

10. The system of claim 1, wherein the actuation member the actuation member initially substantially fills the borehole and travels down the borehole in response to hydraulic pressure applied uphole of the actuation member.

11. The system of claim 1, wherein the actuation member includes a longitudinal aperture extending from an uphole face of the actuation member to a downhole face of the actuation member, and a plug member seat within the longitudinal aperture, the plug member seat configured for receiving and retaining a plug member for blocking the longitudinal aperture.

12. The system of claim 11, wherein the plug member is controllably dissolvable.

13. The system of claim 2, wherein the actuation member includes a leading portion and a trailing portion, the leading portion located downhole of the trailing portion, and wherein the trailing portion is compressible radially inwardly due to force applied by the one or more inward-facing protrusions on the wedged portion when the actuation member moves downhole past the one or more inward-facing protrusions.

14. The system of claim 13, wherein the trailing portion comprises resiliently deformable collets actuated for radially inward compression.

15. A system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein, the casing defining an internal borehole extending longitudinally with the wellbore, the casing having one or more ports extending through the casing, the system comprising:

an actuation member configured for travelling down the borehole in a longitudinal direction;

at least one sliding sleeve member for disposal within the borehole and each having an aperture for receiving the actuation member therein, the at least one sliding sleeve member configured to initially cover a respective port, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port;

wherein the actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the at least one sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the at least one sliding sleeve member;

a stopping member affixed to the casing downhole of one or more of the at least one sliding sleeve member, the stopping member configured to contact the at least one sliding sleeve member after the at least one sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the at least one sliding sleeve member, the stopping member configured to release under a second predetermined amount of force to allow said further downhole travel of the at least one sliding sleeve member;

wherein the first engagement portion and the second engagement portion are configured to release from one another upon said further downhole travel of the at least one sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the at least one sliding sleeve member.

16. The system of claim 15, wherein the stopping member is affixed to the casing downhole of each of the at least one sliding sleeve member.