Patent Grant
10975663
This application claims priority to Canadian Patent Application Serial No. 3042542, entitled “APPARATUS FOR DOWNHOLE FRACKING AND A METHOD THEREOF” filed on May 7, 2019, published Jun. 26, 2019, and which issued as CA 3,042,542 on Aug. 11, 2020, the content of which is incorporated herein by reference in its entirety.
The present disclosure relates generally to an apparatus and method for downhole fracking, and in particular to an apparatus and method for downhole fracking using a pressure-actuated sliding sleeve set.
Downhole fracking has been widely used for increasing the hydrocarbon production of a subterranean formation. For example, downhole fracking may be conducted by running a downhole fracking tool in a wellbore to a target location via a tubing string. The fracking tool comprises a plurality of fracking ports and a valve. The valve is initially in a closed configuration closing the fracking ports and may be actuated to open the fracking ports.
After isolating a section of the wellbore about the target location e.g., by using a pair of packers, the valve is configured to an open configuration opening the fracking ports. Then, a high-pressure fracking fluid is injected into the wellbore along the annulus between the wellbore and the tubing string and jetted out from the opened fracking ports into the formation about the target location to create cracks therein for improving the flow conditions of the hydrocarbon therein, thereby increasing the hydrocarbon production. Usually, the high-pressure fracking fluid comprises suitable solids such as sands for maintaining the created cracks in the formation.
The valve controlling the opening and closing of the fracking ports may be a sliding-sleeve valve which uses a sliding sleeve to open and close the fracking ports. For example, U.S. Pat. No. 7,926,580 to Darnell et al. teaches a coiled tubing multi-zone frac system for fracking a formation adjacent a well using a sliding sleeve and erodible jets. Erodible jets may provide a means for perforating, fracking and flowing the well which takes the place of two separate tools that are otherwise needed to cause a well to flow.
U.S. Pat. No. 8,235,114 to Clem et al. teaches a fracturing and gravel packing tool having features that prevent well swabbing when the tool is picked up with respect to a set isolation packer. An upper or jet valve allows switching between the squeeze and circulation positions without risk of closing the wash pipe valve. The wash pipe valve can only be closed with multiple movements in opposed direction that occur after a predetermined force is held for a finite time to allow movement that arms the wash pipe valve. The jet valve can prevent fluid loss to the formation when being set down whether the crossover tool is supported on the packer or on the smart collet.
U.S. Pat. No. 8,893,810 to Zimmerman et al. teaches the use of a plurality of sliding sleeves deployed on tubing in a wellbore annulus for wellbore fluid treatment. Operators deploy a plug down the tubing to a first sleeve. The plug seats in this first sleeve, and pumped fluid pressure opens the first sleeve and communicates from the tubing to the wellbore annulus. In the annulus, the fluid pressure creates a pressure differential between the wellbore annulus pressure and a pressure chamber on second sleeves on the tubing. The resulting pressure differential opens the second sleeves so that fluid pressure from the tubing can communicate through the second open sleeves. Using this arrangement, one sleeve can be opened in a cluster of sleeves without opening all of them at the same time. The deployed plug is only required to open the fluid pressure to the annulus by opening the first sleeve. The pressure chambers actuate the second sleeves to open up the tubing to the annulus.
U.S. Pat. No. 10,087,734 to Fehr et al. teaches a method for fracturing a formation which includes positioning a fluid treatment string in the formation. The fluid treatment string includes a port configured to pass fracturing fluid from within the string's inner bore to outside the string, and a sliding sleeve located inside string and configured to move by fluid pressure within the inner bore of the fluid treatment string between (i) a first position in which the sliding sleeve covers the port and (ii) a second position in which the sliding sleeve exposes the port to the inner bore. The method also includes applying a fluid pressure within the inner bore such that the sliding sleeve moves from the first position to the second position without the sliding sleeve engaging a sealing device, and pumping fracturing fluid through the inner bore and through the port to fracture a portion of the formation.
US Patent Publication No. 2017/0058644 to Andreychuk et al. teaches a bottom hole actuator tool for locating and actuating one or more sleeve valves spaced along a completion string. A shifting tool includes radially extending dogs at ends of radially controllable, and circumferentially spaced support arms. Conveyance tubing actuated shifting of an activation mandrel, indexed by a J-Slot, cams the arms radially inward to overcome the biasing for in and out of hole movement, and for releasing the arms for sleeve locating and sleeve profile engagement. A cone, movable with the mandrel engages the dogs for positive locking of the dogs in the profile for sleeve opening and closing. A treatment isolation packer can be actuated with cone engagement. The positive engagement and compact axial components results in short sleeve valves.
U.S. Pat. No. 7,398,832 to Brisco teaches an apparatus and method for forming a monodiameter wellbore casing. The casing includes a second casing positioned in an overlapping relation to a first casing. The inside diameter of the overlapping portion and at least a portion of the second casing are substantially equal to the inside diameter of the non-overlapping portion of the first casing. The apparatus includes a support member, an adaptor coupled to the support member, an outer sleeve coupled to the adaptor, a hydraulic slip body coupled to the outer sleeve, a packer cup mandrel coupled to the hydraulic slip body, hydraulic slips coupled to the hydraulic slip body, a shoe coupled to the outer sleeve, an inner mandrel coupled to the shoe and hydraulic slip body, an expansion cone mandrel coupled to the inner mandrel, an expansion cone coupled to the expansion cone mandrel, and a guide nose coupled to the expansion cone mandrel.
The prior-art downhole fracking tools, however, still have disadvantages. For example, some prior-art downhole fracking tools may require a collar locator for proper positioning of the downhole fracking tools. However, with the increased use of premium-thread connections, a casing string may not have any gaps at the collars for the collar locator to position the downhole fracking tool.
Moreover, many prior-art downhole fracking tools require operators to be skilled in not overly pulling the downhole fracking tool through the gap, which depends on how strongly the drag blocks in the collar locator are spring loaded. An insufficient pulling may cause the collar to fail to register on the weight indicator. On the other hand, an overly pulling may, due to the tension in tubing, cause the downhole fracking tool to “jump” uphole through the gap to be engaged, thereby causing the downhole fracking tool be set too high in a fracking sleeve and leading to severe adverse consequences or failures that may be expensive to fix.
Some prior-art downhole fracking tools such as those using J-slots generally require a plurality of steps and consequently a long time to complete a fracking process. For example, in some prior-art downhole fracking tools, a J-slot having up to six positions is used, and the downhole fracking tool needs to cycle through the six positions to complete the fracking process which significantly increases the fracking time.
Many prior-art downhole fracking tools have sophisticated designs with a plurality of parts, and in particular a plurality of moving parts, causing the downhole fracking tools prone to failure in complicated downhole environment due to various factors such as sand clogging, wearing out, insufficient pressure resistance, and/or the like.
Moreover, downhole fracking tools with more parts generally require longer lengths, thereby increasing the manufacturing cost, and causing significant burden to operators because of their larger sizes and higher weights.
According to one aspect of this disclosure, there is provided a downhole valve comprising: a valve body having a longitudinal bore extending therethrough, an uphole shoulder and a downhole shoulder in the longitudinal bore, and at least one port on a sidewall of the valve body and intermediate the uphole and downhole shoulders; and a sliding-sleeve set received in the bore of the valve body and slidable between the uphole and downhole shoulders thereof for configuring the sliding-sleeve set between a closed configuration for closing the at least one port and an open configuration for opening the at least one port. The sliding-sleeve set comprises an uphole sliding sleeve and a downhole sliding sleeve each longitudinally slidable within the longitudinal bore of the valve body; the sliding-sleeve set is in the closed configuration when the downhole sliding sleeve contacts the downhole shoulder of the valve body and the uphole sliding sleeve and the downhole sliding sleeve are in contact with each other; and the sliding-sleeve set is in the open configuration when the downhole sliding sleeve contacts the downhole shoulder of the valve body and the uphole sliding sleeve contacts the uphole shoulder of the valve body.
In some embodiments, the sliding-sleeve set is in an additional closed configuration when the uphole sliding sleeve contacts the uphole shoulder of the valve body and the downhole sliding sleeve contacts the uphole sliding sleeve.
According to one aspect of this disclosure, there is provided a downhole valve comprising: a valve body having a given longitudinal bore extending therethrough, and at least one port at a longitudinal location therealong circumferentially spaced about a sidewall thereof; and a sliding-sleeve set slidably received in the bore of the valve body and comprising an uphole sliding sleeve and a downhole sliding sleeve. The sliding-sleeve set is in a closed configuration for closing the at least one port when the downhole sliding sleeve is at a downhole position in the valve body and the uphole sliding sleeve engages the downhole sliding sleeve; and the sliding-sleeve set is in an open configuration for opening the at least one port when the downhole sliding sleeve is at the downhole position in the valve body and the uphole sliding sleeve is at an uphole position in the valve body.
In some embodiments, the sliding-sleeve set is in an additional closed configuration when the uphole sliding sleeve is at the uphole position in the valve body and the downhole sliding sleeve engages the uphole sliding sleeve and covers said at least one port.
In some embodiments, the downhole valve further comprises an actuation assembly configured for engaging the sliding-sleeve set and actuating the sliding-sleeve set to the open configuration.
In some embodiments, the actuation assembly is further configured for engaging the sliding-sleeve set and actuating the sliding-sleeve set to the additional closed configuration.
According to one aspect of this disclosure, there is provided a downhole valve comprising: a valve assembly having a valve body and at least a first sliding sleeve, the valve body having at least one port, the first sliding sleeve slidably received in a longitudinal bore of the valve body for indirectly or directly opening and closing the at least one port, the first sliding sleeve comprising a circumferential actuation groove; and an actuation assembly, at least a portion of which is extendable into the first sliding sleeve, said actuation assembly comprising an actuation housing axially movably receiving therein a slip assembly, the slip assembly comprising one or more slips in an initial radially inwardly retracted configuration and being radially outwardly extendable upon application of a hydraulic pressure to a radially outwardly extended configuration for engaging the circumferential actuation groove of the first sliding sleeve and for radially outwardly extending said one or more slips to allow engagement thereof with said circumferential actuation groove to then allow for moving the first sliding sleeve thereby opening the at least one port. When the one or more slips are at the radially outwardly extended configuration, the actuation housing of the actuation assembly is longitudinally movable to position a supporting structure on an inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
In some embodiments, the supporting structure is portion of the actuation housing.
In some embodiments, at least one of the one or more slips comprises one or more buttons brazed on an outward surface thereof.
In some embodiments, the one or more buttons are made of tungsten carbide.
In some embodiments, the actuation housing further receives thereon a compressible sealing element uphole of the slip assembly.
In some embodiments, the actuation housing further comprises a circumferential recess on an outer surface thereof for receiving the compressible sealing element.
In some embodiments, when the one or more slips are at the radially outwardly extended configuration and when the portion of the actuation housing is on an radially inward side of the one or more slips, and the compressible sealing element is compressed to engage an inner surface of the valve assembly for forming a seal downhole to the at least one port in an annulus between the valve assembly and the actuation assembly.
In some embodiments, each of the one or more slips comprises at least a second chamfer engageable with an edge of the circumferential actuation groove for, upon application of a longitudinal downward force and release of application of said hydraulic pressure, configuring the one or more slips to a radially inwardly retracted configuration.
In some embodiments, each of the one or more slips is coupled to a spring for biasing the slip to a radially inwardly retracted configuration.
In some embodiments, the actuation assembly further comprises a fluid path for supplying the hydraulic pressure for radially outwardly actuating the one or more slips; the fluid path is in fluid communication with the bore of the valve body when downward force is applied to the actuation assembly and the one or more slips are maintained in, or to be configured to, the radially inwardly retracted configuration and no fracking pressure is applied; and the actuation assembly further comprises a flow-restriction structure or a sealing structure for restricting or completely blocking the fluid communication between the fluid path and the bore of the valve body and for maintaining the hydraulic pressure for radially outwardly actuating the one or more slips when upward force is applied to the actuation assembly and the one or more slips are maintained in, or to be configured to, the radially outwardly extended configuration.
In some embodiments, the slip assembly comprises a piston in the fluid path for being actuated by the hydraulic pressure and having a cone-shaped end engageable with the one or more slips for, upon the application of the hydraulic pressure, radially outwardly actuating the one or more slips.
In some embodiments, each of the one or more slips comprises at least a first chamfer engageable with the cone-shaped end of the piston.
In some embodiments, the compressible sealing element is uphole of and spaced from the piston so as to maintain a gap therebetween, said gap being a part of the fluid path.
In some embodiments, the actuation assembly further comprises an elongated actuation mandrel assembly axially movably received in a longitudinal bore of the actuation housing, said actuation mandrel assembly comprising a longitudinal bore forming a portion of the fluid path; the actuation housing comprises a reduced inner diameter (ID) section; and the actuation mandrel assembly comprises an increased outer diameter (OD) section engageable with the reduced ID section of the actuation housing body when the reduced ID section of the actuation housing body is moved relative to and in close proximity but without contact to said increased OD section so as to thereby form the flow-restriction structure.
In some embodiments, the actuation assembly further comprises an elongated actuation mandrel assembly axially movably received in a longitudinal bore of the actuation housing, said actuation mandrel assembly comprising a longitudinal bore forming a portion of the fluid path; the actuation housing comprises a reduced inner diameter (ID) section at a first location; and the actuation mandrel assembly comprises an increased outer diameter (OD) section engageable with the reduced ID section of the actuation housing body at the first location without contact for forming the flow-restriction structure at the first location when the actuation mandrel assembly is pulled uphole relative to the valve body.
In some embodiments, the actuation assembly further comprises a plug engageable with a plug seat at a second location of the bore of the valve body for forming the sealing structure at the second location.
In some embodiments, upon downhole movement of said actuation mandrel assembly and application of the hydraulic pressure, said increased OD section is less engaged with said actuation housing body, so as to allow passage or increased passage of hydraulic fluid between said increased OD section and said reduced ID section so as to allow flushing said fluid path using said hydraulic fluid.
In some embodiments, the plug is a ball.
In some embodiments, the plug is coupled to a downhole end of the actuation mandrel assembly; and the actuation housing further comprises a circumferential ridge on an inner surface thereof about the second location for engaging the actuation mandrel assembly and establishing a seal or forming a flow-restriction structure about the second location, when the actuation mandrel assembly is pulled uphole relative to the valve body.
In some embodiments, the plug is coupled at an uphole end thereof a collet for receiving a downhole end of the actuation mandrel assembly.
In some embodiments, the downhole valve further comprises a second sliding sleeve slidably received in the longitudinal bore of the valve body and uphole to the first sliding sleeve. The at least one port is opened when the first sliding sleeve is at a downhole position and the second sliding sleeve is at an uphole position; and the at least one port is closed when the first sliding sleeve is at a downhole position and the second sliding sleeve is adjacent the first sliding sleeve, or when the second sliding sleeve is at the uphole position and the first sliding sleeve is adjacent the second sliding sleeve.
In some embodiments, the at least one port is closed when the first sliding sleeve is at an uphole position covering the at least one port; and the at least one port is opened when the first sliding sleeve is at a downhole position uncovering the at least one port.
In some embodiments, the first sliding sleeve comprises at least one aperture at a position overlapping the at least one port of the valve body when the first sliding sleeve is at an uphole position, thereby opening the at least one port of the valve body; and the first sliding sleeve covers the at least one port and the at least one aperture is misaligned with the at least one port when the first sliding sleeve is at a downhole position thereby closing the at least one port of the valve body.
According to one aspect of this disclosure, there is provided a method of fracking a subterranean formation about a section of a wellbore using the above-described downhole valve. The method comprises: locating the valve assembly in said section of the wellbore; running the actuation assembly downhole to pass the valve assembly; pulling the actuation mandrel assembly uphole to move the actuation assembly uphole and form the flow-restriction structure; while pulling the actuation mandrel assembly uphole, injecting a pressurized fluid through the longitudinal bore of the actuation mandrel assembly to actuate the one or more slips radially outwardly; continuing to pull the actuation mandrel assembly uphole to allow the one or more slips to engage the circumferential actuation groove; further continuing to pull the actuation mandrel assembly uphole to slide the first and second sliding sleeves uphole until the second sliding sleeve is at the uphole position and the first sliding sleeve is adjacent the second sliding sleeve; pushing the actuation mandrel assembly downhole while maintain the pressurized fluid to slide the first sliding sleeve to the downhole position to open the at least one port; further moving an uphole portion of the actuation assembly downhole while maintaining the application of the pressurized fluid to extend the actuation housing of the actuation assembly downhole so as to position the portion of the actuation housing on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration; and fracking the formation by injecting a fracking fluid stream downhole and jetting the fracking fluid stream through the at least one port into the formation.
In some embodiments, the method further comprises: after said fracking the formation, pulling the actuation mandrel assembly uphole and injecting the pressurized fluid to slide the first sliding sleeve to adjacent the second sliding sleeve to close the at least one port.
In some embodiments, the method further comprises: stopping the application of the pressurized fluid and pulling the actuation mandrel assembly uphole to configure the one or more slips to a radially inwardly retracted configuration and allow moving the actuation assembly uphole and out of the valve assembly.
According to one aspect of this disclosure, there is provided a method of fracking a subterranean formation about a section of a wellbore. The method comprises: locating a valve assembly in said section of the wellbore, said valve assembly having a valve body and a first and a second sliding sleeves slidably received in a longitudinal bore thereof, the valve body having at least one fracking port, the first sliding sleeve located at a downhole position and comprising a circumferential actuation groove, and the second sliding sleeve is uphole to but adjacent to the first sliding sleeve and covering the at least one fracking port; running an actuation assembly downhole to pass the valve assembly, said actuation assembly comprising one or more slips reconfigurably in a radially inwardly retracted configuration; pulling the actuation assembly uphole; while pulling the actuation assembly uphole, applying a hydraulic pressure so as to actuate the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve; continuing to pull the actuation assembly uphole to slide the first and second sliding sleeves uphole until the second sliding sleeve is uphole to the at least one fracking port; pushing the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port; further moving an uphole portion of the actuation assembly downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration; and fracking the formation by injecting a fracking fluid stream downhole and jetting the fracking fluid stream through the at least one fracking port into the formation.
In some embodiments, the step of said further moving the uphole portion of the actuation assembly downhole comprises: further moving the uphole portion of the actuation assembly downhole to position the supporting structure on the radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration and to compress a compressible sealing element to radially outwardly expand at least at a central portion thereof and engage an inner surface of the first sliding sleeve, thereby forming a seal downhole to the at least one fracking port in the annulus between the valve assembly and the actuation assembly.
In some embodiments, said actuation assembly further comprises a flow path fluidly connecting a bore of the actuation assembly to the bore of the valve assembly and to a slip-actuation structure for actuating the one or more slips; and said actuating the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve comprises: restricting or isolating the flow path to the bore of the valve assembly and applying a hydraulic pressure from the bore of the actuation assembly through the flow path to the slip-actuation structure to actuate the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve.
In some embodiments, the method further comprises: after said step of restricting or isolating the flow path, reducing said restriction of the flow path to the bore of the valve assembly so as to allow passage or increased passage of hydraulic fluid therethrough so as to allow flushing said fluid path using said hydraulic fluid.
In some embodiments, the slip-actuation structure comprises a longitudinally movable piston having a chamfer engageable with a chamfer of each of the one or more slips for radially outwardly actuating the one or more slips; and said restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the slip-actuation structure comprises: restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the piston to actuate the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve.
In some embodiments, the slip-actuation structure comprises the radially inward side of each of the one or more slips; and said applying the hydraulic pressure through the flow path to the one or more slips to actuate the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve comprises: restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the radially inward side of the one or more slips to actuate the one or more slips radially outwardly to engage the circumferential actuation groove of the first sliding sleeve.
In some embodiments, said pushing the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port comprises: maintaining the hydraulic pressure and pushing the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port.
In some embodiments, the method further comprises: after said pushing the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port and before said fracking the formation, increasing the hydraulic pressure to compress a compressible sealing element to radially outwardly expand at least at a central portion thereof and engage an inner surface of the first sliding sleeve, thereby forming a seal downhole to the at least one fracking port in the annulus between the valve assembly and the actuation assembly.
In some embodiments, said further moving the uphole portion of the actuation assembly downhole comprises: after the actuation assembly has been moved to a downhole position to slide the first sliding sleeve downhole to open the at least one fracking port and while a downhole portion of the actuation assembly is stopped at the downhole position, allowing the uphole portion of the actuation assembly to further move downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
In some embodiments, said further moving the uphole portion of the actuation assembly downhole comprises: further pushing the uphole portion of the actuation assembly downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
In some embodiments, said further moving an uphole portion of the actuation assembly downhole and said fracking the formation comprises: injecting the fracking fluid stream downhole and jetting the fracking fluid stream through the at least one fracking port into the formation for fracking the formation and for further moving the uphole portion of the actuation assembly downhole to cause a supporting structure to move to a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
According to one aspect of this disclosure, there is provided a method of fracking a subterranean formation about a section of a wellbore. The method comprises: locating a valve assembly in said section of the wellbore, said valve assembly having a valve body and a first sliding sleeve slidably received in a longitudinal bore thereof, the valve body having at least one fracking port, the first sliding sleeve comprising a circumferential actuation groove, and the first sliding sleeve being secured at an uphole position covering the at least one fracking port and at a distance to a downhole shoulder of the valve body; running an actuation assembly downhole to pass the valve assembly, said actuation assembly comprising one or more slips reconfigurably in a radially inwardly retracted configuration; pulling the actuation assembly uphole; while pulling the actuation assembly uphole, actuating the one or more slips radially outwardly to a radially outwardly extended configuration so as to engage a downhole end of the first sliding sleeve; continuing to pull the actuation assembly uphole to unsecure the first sliding sleeve; reconfiguring the one or more slips to the radially inwardly retracted configuration and further pulling the actuation assembly uphole; actuating the one or more slips radially outwardly to the radially outwardly extended configuration and pushing the actuation assembly downhole to engage the one or more slips with the circumferential actuation groove of the first sliding sleeve; continuing to push the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port; further moving an uphole portion of the actuation assembly downhole to position a supporting structure on the radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration; and fracking the formation by injecting a fracking fluid stream downhole and jetting the fracking fluid stream through the at least one fracking port into the formation.
In some embodiments, the step of said further moving the uphole portion of the actuation assembly downhole comprises: further moving the uphole portion of the actuation assembly downhole to position the supporting structure on the radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration and to compress a compressible sealing element to radially outwardly expand at least at a central portion thereof and engage an inner surface of the first sliding sleeve, thereby forming a seal downhole to the at least one fracking port in the annulus between the valve assembly and the actuation assembly.
In some embodiments, said actuation assembly further comprises a flow path fluidly connecting a bore of the actuation assembly to the bore of the valve assembly and to a slip-actuation structure for actuating the one or more slips; and the steps of said actuating the one or more slips radially outwardly comprise: restricting or isolating the flow path to the bore of the valve assembly and applying a hydraulic pressure from the bore of the actuation assembly through the flow path to the slip-actuation structure to actuate the one or more slips radially outwardly.
In some embodiments, the slip-actuation structure comprises a longitudinally movable piston having a chamfer engageable with a chamfer of each of the one or more slips for radially outwardly actuating the one or more slips; and said restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the slip-actuation structure comprises: restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the piston to actuate the one or more slips radially outwardly.
In some embodiments, the slip-actuation structure comprises the radially inward side of each of the one or more slips; and said applying the hydraulic pressure through the flow path to the slip-actuation structure comprises: restricting or isolating the flow path to the bore of the valve assembly and applying the hydraulic pressure from the bore of the actuation assembly through the flow path to the radially inward side of the one or more slips to actuate the one or more slips radially outwardly.
In some embodiments, said continuing to push the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port comprises: maintaining the hydraulic pressure and continuing to push the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port.
In some embodiments, the method further comprises: after said continuing to push the actuation assembly downhole to slide the first sliding sleeve downhole to open the at least one fracking port and before said fracking the formation, increasing the hydraulic pressure to compress a compressible sealing element to radially outwardly expand at least at a central portion thereof and engage an inner surface of the first sliding sleeve, thereby forming a seal downhole to the at least one fracking port in the annulus between the valve assembly and the actuation assembly.
In some embodiments, said step of further moving the uphole portion of the actuation assembly downhole comprises: after the actuation assembly moved to a downhole position to slide the first sliding sleeve downhole to open the at least one fracking port and while a downhole portion of the actuation assembly is stopped at the downhole position, allowing the uphole portion of the actuation assembly to further move downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
In some embodiments, said step of further moving the uphole portion of the actuation assembly downhole comprises: further pushing the uphole portion of the actuation assembly downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
In some embodiments, said further moving an uphole portion of the actuation assembly downhole and said fracking the formation comprises: injecting the fracking fluid stream downhole and jetting the fracking fluid stream through the at least one fracking port into the formation for fracking the formation and for further moving the uphole portion of the actuation assembly downhole to position a supporting structure on a radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration.
According to one aspect of this disclosure, there is provided a method of fracking a subterranean formation about a section of a wellbore. The method comprises: locating a valve assembly in said section of the wellbore, said valve assembly having a valve body and a first sliding sleeve slidably received in a longitudinal bore thereof, the valve body having at least one fracking port, the first sliding sleeve comprising at least one aperture alignable with the at least one fracking port of the valve body and a circumferential actuation groove, and the first sliding sleeve located at a downhole position covering the at least one fracking port; running an actuation assembly downhole to pass the valve assembly, said actuation assembly comprising one or more slips reconfigurably in a radially inwardly retracted configuration; pulling the actuation assembly uphole; while pulling the actuation assembly uphole, actuating the one or more slips radially outwardly to reconfigure the one or more slips to a radially outwardly extended configuration and engage the circumferential actuation groove of the first sliding sleeve; continuing to pull the actuation assembly uphole to slide the first sliding sleeve to an uphole position and secured therein to align the at least one aperture thereof with the at least one fracking port of the valve body thereby opening the at least one fracking port; injecting a fracking fluid stream downhole into the valve assembly; allowing the fracking fluid stream to further push the actuation assembly downhole to position a supporting structure on the inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration; and jetting the fracking fluid stream through the at least one fracking port into the formation.
According to one aspect of this disclosure, there is provided a method of fracking a subterranean formation about a section of a wellbore. The method comprises: locating a valve assembly in said section of the wellbore, said valve assembly having a valve body and a first sliding sleeve slidably received in a longitudinal bore thereof, the valve body having at least one fracking port, the first sliding sleeve comprising a circumferential actuation groove, and the first sliding sleeve being secured at an uphole or downhole position covering the at least one fracking port and at a distance to a respective uphole or downhole shoulder of the valve body; running an actuation assembly downhole to pass the valve assembly, said actuation assembly comprising one or more slips reconfigurably in a radially inwardly retracted configuration; pulling the actuation assembly uphole; while pulling the actuation assembly uphole, actuating the one or more slips radially outwardly to a radially outwardly extended configuration so as to engage a downhole end of the first sliding sleeve; continuing to move the actuation assembly uphole or downhole to slide the first sliding sleeve to open the at least one fracking port; further moving an uphole portion of the actuation assembly downhole to position a supporting structure on the radially inward side of the one or more slips for supporting the one or more slips at the radially outwardly extended configuration; and fracking the formation by injecting a fracking fluid stream downhole and jetting the fracking fluid stream through the at least one fracking port into the formation.
Further advantages and other embodiments of the invention will now appear from the above along with the following detailed description of the various particular embodiments of the invention, taken together with the accompanying drawings each of which are intended to be non-limiting and for illustrative purpose only, in which:
Embodiments herein disclose an apparatus and method for downhole fracking using a pressure-actuated sliding sleeve set. In the following description, the term “downhole” refers to a direction along a wellbore towards the end of the wellbore, and may (e.g., in a vertical wellbore) or may not (e.g., in a horizontal wellbore) coincide with a “downward” direction. The term “uphole” refers to a direction along a wellbore towards surface, and may (e.g., in a vertical wellbore) or may not (e.g., in a horizontal wellbore) coincide with an “upward” direction.
Turning to
Also shown in
The valve housing 122 is coupled to two couplings 124 and 126 at an uphole end 128 and a downhole end 130, respectively, using suitable coupling means such as threading, bolting, welding, and/or the like. The couplings 124 and 126 extend into the tubular body 122 and form a pair of stoppers 132 and 134, respectively, for limiting the sleeve set 108 movable therebetween. The valve housing 122 also comprises a retaining groove 136 adjacent the uphole stopper 132.
As shown in
The downhole sliding sleeve 108B comprises a circumferential actuation groove 142 adjacent a downhole end 130 thereof for engaging the actuation assembly 110 to open and close the fracking ports 104.
The uphole sliding sleeve 108A has a length Lu shorter than the distance Du, between the uphole stopper 132 and the fracking port 104, and the downhole sliding sleeve 108A has a length Ld shorter than the distance Dd between the downhole stopper 134 and the fracking ports 104 (see
As shown in
When the slips 160 are in a radially inwardly retracted or collapsed configuration, the actuation assembly 110 has an outer diameter (OD) smaller than the inner diameter (ID) of the sleeve set 108 to allow the actuation assembly 110 to move therethrough as needed.
When the slips 160 are in a radially outwardly extended configuration (see
As shown in
The actuation housing body 162 comprises an uphole body section 162A and a downhole body section 162B coupled together using suitable means such as threading, bolting, pins, welding, and/or the like. The uphole body section 162A comprises a section 172 with a reduced ID such as a circumferential inner ridge radially inwardly extending from the inner surface thereof, for forming a flow-restriction structure against the actuation mandrel assembly 156 to facilitate the radially outwardly actuation of the slips 160 using a fluid pressure (described in more detail later).
On its outer surface, the actuation housing body 162 comprises one or more clean-out ports 174 adjacent an uphole end 128 thereof. Downhole to the clean-out ports 174, the actuation housing body 162 comprises a circumferential recess 176 on the outer surface thereof and one or more fluid-actuation ports 182 in the recess 176.
The circumferential recess 176 axially extending from an uphole shoulder 178 on the uphole body section 162A to a downhole shoulder 180 (having a radial height of HS) on the downhole body section 162B for receiving therein the compressible sealing element 152 and the slip assembly 154. The axial length of the circumferential recess 176 between the uphole and downhole shoulders 178 and 180 is greater than the total axial length of the compressible sealing element 152, the piston 204, and the slip 160 such that a gap 188 between the compressible sealing element 152 (or the coupling section 152B thereof) and the piston 204 is maintained for applying a downhole actuation force to the piston 204 (detailed in more detail later).
In these embodiments, the downhole body section 162B extends into the uphole body section 162A and forms a circumferential shoulder for supporting a plug seat 184 received in the uphole body section 162A. On the outer surface, the downhole end 186 of the uphole body section 162A forms a supporting structure (also denoted a “tongue”) which, at certain stage of operation, may move under the radially outwardly extended slips 160 to support the slips 160 in position (described later).
As shown in
The downhole section 214 of the slip 160 has a radial thickness HD smaller than that of the main section 212.
As shown in
Downhole from the coupling section 152B, the slip holder 202 comprises a plurality of flushing holes 224 for flushing the tool 100 to remove any debris or solids entering therein, and one or more windows 226 on a sidewall thereof adjacent the downhole end 130 for receiving the one or more slips 160 therein. The one or more windows 226 have a longitudinal length greater than or equal to that of the main section 212 of the slips 160. When the slips 160 are received in the windows 226, the downhole section 214 of each slip 160 is received into the bore 106 of the slip holder 202 such that the sidewall portion 228 of the slip holder 202 downhole to the windows 226 retains the slips 106.
The slip holder 202 further comprises a ring-shaped end wall 230 at the downhole end 130 having a central opening 232 with an ID substantially the same as the OD of the downhole body section 162B of the actuation housing body 162 for allowing the downhole body section 162B to extend therethrough. The radial thickness of the ring-shaped end wall 230, calculated as the difference of the ID of the slip holder 202 and that of the end-wall opening 232, is denoted as HE. In these embodiments, the radial thickness HE of the end wall 230, the radial height of HS of the downhole shoulder 180 of the circumferential recess 176 (see
As the radial thickness HD of the downhole section 214 of the slip 160 is greater than the radial thickness HE of the end wall 230 of the slip holder 202 and is also greater than the radial height of HS of the downhole shoulder 180 of the circumferential recess 176, the compressible sealing element 152 and the slip assembly 154 would not slide downhole off the actuation housing 150 regardless whether the slips 160 are configured in the radially inwardly retracted configuration or are actuated to the radially outwardly extended configuration.
The hollow mandrel 276 generally has an OD smaller than the ID of the actuation housing 150 to allow it movable in the bore 106 of the actuation housing 150, and the downhole end 282 thereof comprises a plurality of openings or slots 284 for fluid communication.
In these embodiments, the hollow mandrel 276 comprises an OD-enlarged section 280 with an OD slightly smaller than the ID of the ID-reduced section 172 of the actuation housing body 162, at an axial location engageable therewith without contact, when the actuation mandrel assembly 156 is pulled or otherwise configured to an uphole position. For example, in some embodiments, the ID-reduced section 172 has an ID of 1.125″ (i.e., 1.125 inches) +0.005″/−0.000″, and the OD-enlarged section 280 has an OD of 1.120″+0.000″/−0.005″, which give rise to a 0.005″ to 0.015″ clearance therebetween.
Thus, when the actuation mandrel assembly 156 is pulled or otherwise configured to an uphole position, the OD-enlarged section 280 of the hollow mandrel 276 and the ID-reduced section 172 of the actuation housing body 162 may form a flow restriction for maintaining the fluid pressure in a related fluid path (described later) without the risk of wearing caused by the relative movement between the OD-enlarged section 280 and the ID-reduced section 172 and/or the risk of damage during an equalization process after fracking.
Those skilled in the art will appreciate that, in some embodiments, the OD of the OD-enlarged section 280 of the hollow mandrel 276 may be substantially the same as the ID of the ID-reduced section 172 of the actuation housing body 162 to allow them to form a seal that completely blocks the fluid communication between the two opposite sides thereof, when the actuation mandrel assembly 156 is pulled or otherwise configured to an uphole position. Such a seal will also maintain the fluid pressure in the related fluid path. However, the relative movement between the OD-enlarged section 280 of the hollow mandrel 276 and the ID-reduced section 172 of the actuation housing body 162 may cause either or both of them to wear out and fail.
The downhole tool 100 may be used in a downhole fracking system for subterranean formation fracking. In various embodiments, the downhole fracking system may comprise one or more spaced valve assemblies 102 and one actuation assembly 110 may be used for actuating the valve assemblies 102 to the open configuration for fracking.
As shown, a wellbore having a horizontal wellbore portion 302 is drilled in the subterranean formation 304. Although
In various embodiments, the wellbore 302 may be an oil or gas well and is cased with a casing string 306 which may be cemented or uncemented in the wellbore 302.
The casing string 306 comprises a plurality of valve assemblies 102 spaced by other suitable subs. Each valve assembly 102 is used for fracturing a respective frack zone or stage and the sleeve set 108 thereof is in the closed configuration before fracking. Hereinafter, the term “zone” and “stage” refer to a portion of the wellbore to be fractured, and may be used interchangeably.
In some embodiments, an actuation assembly 110 is coupled to a coiled or jointed tubing 308 for fracking one stage at a time starting from the toe-most stage and then moving uphole. During the fracking of each stage, the actuation assembly 110 is extended into the stage to be fractured and actuates the sleeve set 108 of the valve assembly 102 to the open configuration and opens the fracking ports 104 to provide access to the formation 304.
For example, the actuation assembly 110 may first extend into the valve assembly 102A in the toe-most stage and actuate the sleeve set 108 thereof to open the fracking ports 104 for fracking. As will be described in more detail later, the actuation of the sleeve set 108 also seals the bore 106 of the valve assembly 102A at a position downhole to the fracking ports 104. A high-pressure fracking fluid stream is then pumped downhole along the annulus between the casing string 306 and the coiled tubing 308 and jets out of the opened fracking ports 104 for fracking the formation 304 thereabout.
After fracking, the fracking ports 104 may be closed as needed to isolate the fractured stage for various purposes such as for preventing cross flow to previously fractured stages, minimizing sand backflow into the wellbore 302 during production, and/or the like. Then, the actuation assembly 110 is moved uphole into the valve assembly 102B for fracking the stage thereof, and then the valve assembly 102C after the stage of the valve assembly 102B is fractured.
In the following, the fracking process is described with an example of fracking a formation stage using one valve assembly and one actuation assembly 110 as shown in
As shown in
The valve assembly 102 is then coupled to a casing string 306 of about the same ID thereof (e.g., both the valve assembly 102 (and in particular the sleeve set 108 thereof) and the casing string 306 having an ID of about 4″), inserted into a wellbore 302, and positioned therein at a target fracking location for fracking the subterranean formation about a section of the wellbore 302. The casing string 306 may be cemented or uncemented.
As shown in
As shown in
As shown in
As shown in
A fluid path is thus formed, guiding the pressurized fluid 318 to flow through the bore 106 of the actuation mandrel assembly 156, the slots 284 of the hollow mandrel 276, the annulus 322 between the collet 254/hollow mandrel 276 and the actuation housing 150, the slots 256 of the plug assembly 158, the annulus 322 between the collet 254 of the plug assembly 158 and the actuation housing 150, the one or more fluid-actuation ports 182, and the fluid passage 192 (i.e., the annulus between the actuation housing body 162 and the compressible sealing element 152; see
As shown in
The leaked fluid 320 may flow through the annulus between the mandrel 276 and the actuation housing 150, and out of the clean-out ports 174 of the actuation housing body 162 into the annulus between the actuation assembly 110 and the sleeve set 108 for circulation.
As shown in
As shown in
Stopping the sleeve set 108 causes a tension to the coiled tubing 308 which may be detected at the surface. In response, the actuation assembly 110 is pushed downhole, as shown in
Consequently, the actuation assembly 110 pushes the downhole sliding sleeve 108B downhole to engage the downhole stopper 134 of the valve assembly 102. The fracking ports 104 are then opened.
As shown in
As shown in
During fracking, the actuation assembly 110 is under a downhole pressure caused by the high-pressure fracking fluid stream 332. As the actuation assembly 110 is retained in position by the engagement between the downhole edge 142B of the actuation groove 142 and the slips 160, each slip 160 is under an inward force applied to the downhole outward-facing chamfer 220 thereof. However, the tongue 186 under the slips 160 supports the slips 160 against the inward force and improves the pressure-resistance of the actuation assembly 110.
Thus, the downhole edge 142B of the actuation groove 142, the slips 160, and the tongue 186 under the slips 160 provide a load-bearing structure for retaining the actuation assembly 110 in place under the high fracking pressure during the fracking process.
The high-pressure fracking fluid stream 332 reinforces the load-bearing structure. As can be seen from
The plug 252 of the plug assembly 158 is pressed by the high-pressure fracking fluid stream 332 against the plug seat 184 and forms a metal-to-metal seal to prevent the high-pressure fracking fluid stream 332 from flowing further downhole through the bore 106. In some alternative embodiments, the plug 252 may be made of or comprise other suitable material such as elastomer for forming a seal to prevent the high-pressure fracking fluid stream 332 from flowing further downhole through the bore 106.
At the step shown in
As shown in
As shown in
By the end of the process of fracking a stage, a pressure differential may form across the compressible sealing element 152 as the pressure “below” (or downhole to) the compressible sealing element 152 is usually higher than the pressure “thereabove” (or uphole thereto). Such a pressure differential across the two ends of the compressible sealing element 152 may maintain the compressible sealing element 152 in a compressed configuration and not allow the compressible sealing element 152 to relax and return to its uncompressed shape, even after the compressive load has been removed. In this case, moving the compressed compressible sealing element 152 elements may cause damage thereto.
Therefore, at the end of the process of fracking a stage, a pressure equalization is required to equalize the pressure between the uphole and downhole ends of the compressible sealing element 152 by pulling the plug 252 away from the seat 184 to allow fluid to flow from downhole through the seat 184 and the clean-out ports 174 (acting as equalization ports) to above the compressible sealing element 152.
Those skilled in the art will appreciate that, in some embodiments, after the fracking ports 104 are opened, the actuation assembly 110 may be pushed downhole for a short distance such that the downhole edge 142B actuates the slips 160 to the radially inwardly retracted configuration. Then, the actuation assembly 110 may be moved to another fracking location.
In the embodiments shown in
For example, in some alternative embodiments, at the end of step shown in
As another example, in some alternative embodiments, after the step shown in
While the high-pressure fracking fluid stream 332 is jetted out through the fracking ports 104 for fracking the formation thereabout, the high-pressure fracking fluid stream 332 also pushes the actuation housing body 162 and the tongue 186 thereof downhole thereby compressing the compressible sealing element 152 to radially outwardly expand at least at a central portion thereof and moving the tongue 186 thereof “under” the radially outwardly extended slips 160 to support the slips 160 in position.
In some alternative embodiments, after the step shown in
During the fracking process, the high-pressure fracking fluid stream 332 locks the tongue 186 under the slips 160 to support the slips 160 and maintains the compression of the compressible sealing element 152 thereby reinforcing the seal of the annulus between the actuation assembly 110 and the valve assembly 102.
In some embodiments similar to that shown in
After fracking, the actuation assembly 110 moves uphole through the valve assemblies 102 and in some embodiments may close the fracking ports 104 of each valve assembly 102 while moving therethrough.
In these embodiments, the wellbore 302 may be a vertical well or a horizontal well and may be cased or uncased. The valve assembly 102 is configured to the closed configuration and sandwiched between a pair of sealing components such as a pair of packers 336 which are coupled to a tubing string 338. The tubing string 338 is then extended downhole to a target location 340A in the wellbore 302.
Then, the packers 310 are actuated to seal the annulus between the wellbore 302 and the tubing string 338. An actuation assembly 110 is coupled to a coiled tubing 308 and extended downhole into the valve assembly 102 to open the fracking ports 104 and then the formation 304 about the target location 340A is fractured in a manner similar to
After fracking the formation 304 about target location 340A, the valve assembly 102 may be reconfigured to the closed configuration and move to another location 340B or 340C for further fracking.
As those skilled in the art will appreciate, in various embodiments with suitable stage-isolation means, the fracking stages may be fractured in any suitable order such as from heel to toe, from toe to heel, or in other predefined order. However, it may be required that prior to fracking a stage, all fracking ports 104 uphole thereto to be closed.
In some embodiments, the downhole tool 100 disclosed herein may also be used with a sand-jet perforator uphole thereto for sand-jet perforating a stage in the situation that a screen-out occurs (i.e., the flow path for the fracking fluid stream 332 is plugged in the formation, at the fracking ports, or at another place thereof), such that operators may sand-jet perforate the casing and fracking the formation a few meters uphole to the target fracking location, without abandoning the stage.
In these embodiments, the sand-jet perforator may be a cylinder with four holes (e.g., with a diameter of about 3/16″) spaced equally around the circumference thereof. When a screen-out occurs, the actuation assembly 110 actuates the valve assembly 102 and closes the fracking ports 104. Then, a slurry is pumped down the tubing (e.g., at about 500 liters per minute) and jets out from the holes to perforate the casing-string section. A high-pressure fracking fluid stream is then pumped downhole to frack the formation through the newly perforated casing-string section.
The downhole tool 100 disclosed herein has several advantages. For example, the downhole tool 100 disclosed herein generally only has two operational positions (pulling uphole and running downhole), thereby significantly reducing the time for completing a fracking process.
Compared to some prior-art downhole fracking tools, the downhole tool 100 disclosed herein comprises less components and in particular less moving parts with a simpler design.
According to various aspects, the downhole tool 100 disclosed herein provides a plurality of circulation paths with a plurality of flushing holes 224 and 242 (see
Those skilled in the art will appreciate that alternative embodiments are readily available. For example, referring to
Similar to the embodiments described above, when the actuation assembly 110 is pulled uphole and a pressurized fluid is injected into the bore of the hollow mandrel 276, the flow restriction or seal between the first circumferential inner ridge 172 and the first OD-enlarged section 280 of the hollow mandrel 276 and the flow restriction or seal between the second circumferential inner ridge 352 and the second OD-enlarged section 292 of the hollow mandrel 276 downhole to the ports 284 ensure a fluid path to the uphole side of the piston 204 for creating a back pressure thereto to actuate the piston 204 downhole and radially outwardly extend the slips 160. Such flow restriction and seal are removed when the actuation assembly 110 is pushed downhole.
Those skilled in the art will appreciate that in some alternative embodiments similar to that shown in
In above embodiments, the OD-enlarged section 280 of the hollow mandrel 276 is required to have an OD about the same or slightly smaller than the ID of the circumferential inner ridge 172 of the actuation housing body 162 to form a seal or a flow restriction when the actuation assembly 110 is pulled uphole.
The actuation assembly 110 is similar to that shown in
When the button-slips 404 are in the radially inwardly retracted configuration, the actuation assembly 110 has an OD smaller than the ID of the sleeve set 108 to allow the actuation assembly 110 to move therethrough as needed.
The actuation housing 150 is similar to that shown in
The actuation housing body 162 comprises an uphole body section 162A and a downhole body section 162B coupled together using suitable means such as threading, bolting, pins, welding, and/or the like. Similar to the actuation housing body 162 shown in
The uphole body section 162A comprises a first circumferential inner ridge 172 for forming a flow restriction against the actuation mandrel assembly 156 to radially outwardly actuate the slips 160 using a fluid pressure (described in more detail later).
On its outer surface, the actuation housing body 162 comprises one or more clean-out ports 174 adjacent an uphole end 128 thereof. Downhole to the clean-out ports 174, the actuation housing body 162 comprises a circumferential recess 176 on the outer surface thereof. The circumferential recess 176 axially extending from an uphole shoulder 178 on the uphole body section 162A to a downhole shoulder 180 on the downhole body section 162B for receiving therein the compressible sealing element 152 and the button-slip assembly 402. The actuation housing body 162 further comprises one or more slip-accessing holes 406 for the one or more button-slips 404 to access, and a second circumferential inner ridge 352 downhole to the slip-accessing holes 406 and suitable for engaging the hollow mandrel 276 when the actuation mandrel assembly 156 is pulled uphole against the circumferential ridge 168 of the actuation housing 150.
As shown, the button-slip assembly 402 comprises a tubular button-slip holder 422 having a longitudinal bore 106 extending therethrough and one or more slip-recesses 424 (e.g., two sets of eight recesses) on an outer surface of the sidewall thereof for receiving therein the one or more button-slips 404. Each slip-recess 424 has a suitable size of area (e.g., about 1.75 square inches) for providing sufficient force to the sleeve 108B, and is in communication with a reduced-diameter slip-hole 426 at the bottom thereof thereby allowing the respective button-slip 404 to partially move through the sidewall of the button-slip holder 422 into the bore 106.
Referring back to
A locking bar 430 is then fastened to the button-slip holder 422 overlapping the grooves 446 of one or more longitudinally aligned button-slips 404 by using suitable fastening means such as screws 432.
The downhole tool 100 in these embodiments may be operated in a similar manner as shown in
Similar to the first stage shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
The high-pressure fracking fluid stream 332 also applies a downhole pressure to the actuation assembly 110.
The downhole edge 142B of the actuation groove 142, the button-slip 404, and the actuation housing body 162 under the button-slip 404 provide a load-bearing structure for retaining the actuation assembly 110 in place under the high fracking pressure during the fracking process. The plug 252 is pressed against the plug seat 184 and forms a metal-to-metal seal to prevent the high-pressure fracking fluid stream 332 from flowing further downhole through the bore 106. As described above, in some alternative embodiments, the plug 252 may be made of or comprise other suitable material such as elastomer for forming a seal to prevent the high-pressure fracking fluid stream 332 from flowing further downhole through the bore 106.
At the step shown in
As shown in
As shown in
Other alternative embodiments are also readily available. For example, while in above embodiments the actuation assembly 110 comprises a slip assembly 154/402 for engaging a circumferential actuation groove 142 of the sleeve set 108, in some alternative embodiments the slip assembly 154/402 and the circumferential actuation groove 142 may comprise matching profiles. The sleeve sets 108 of different valve assemblies 102 may comprise different sleeve-profiles each may only match the slip-profile of one slip assembly 154/402. In this manner, a plurality of valve assemblies 102 may be used, and may be selectively actuated to the open configuration by selectively using an actuation assembly 110 having a corresponding slip-profile.
In another embodiment wherein button-slips 404 are used, the downhole sleeve 108B may comprise a plurality of circumferential actuation-grooves each having a width matching the diameter of a corresponding button-slip 404. The actuation-grooves of different valve assembly 102 may have different widths and/or spacing thereby giving rise to different sleeve-profiles. Each profile only matches one actuation assembly 110 having button-slips 404 with corresponding diameters and/or spacing.
Although in above embodiments the button-slips 404 may comprise tungsten carbide buttons 448, in some embodiments, at least some button-slips 404 may not comprise any tungsten carbide buttons 448.
As shown in
Although in above embodiments, the actuation groove 142 is used for actuating the sleeve set 108, in some embodiments, the downhole sliding sleeve 108B does not comprise any actuation groove 142. In these embodiments, the actuation assembly 110 comprises one or more spring-biased button-slips 404 having tungsten carbide buttons 448. Moreover, positioning means such as a collar locator may be needed for properly positioning the actuation assembly 110 for fracking. When the actuation assembly 110 is positioned at a proper location, the button-slips 404 are actuated by using a hydraulic pressure as described above to the radially outwardly extended configuration. The tungsten carbide buttons 448 thereof may “bite” into the downhole sliding sleeve 108B for engaging and moving the sleeve set 108. As described above, after the hydraulic pressure is removed, the springs may bias the button-slips 404 to the radially inwardly retracted configuration.
In some embodiments, the actuation assembly 110 may not comprise the compressible sealing element 152. Rather, the actuation assembly 110 may comprise other suitable compressible-element such as an axially compressible spring for, when under a predetermined downhole pressure, actuating the tongue downhole under the slips 160 to support the slips 160. However, additional means is required for forming a seal downhole to the fracking ports 104 in the annulus between the valve assembly 102 and the actuation assembly 110 for preventing the fracking fluid from flowing downhole through the valve assembly 102.
In some embodiments, the actuation assembly 110 may not comprise the compressible sealing element 152 or other suitable compressible-element. The actuation housing body 162 and the tongue 186 thereof may still be actuated downhole to move the tongue 186 under the slips 160 to support the slips 160. However, additional means is required for forming a seal downhole to the fracking ports 104 in the annulus between the valve assembly 102 and the actuation assembly 110 for preventing the fracking fluid from flowing downhole through the valve assembly 102.
Although in above embodiments, the sleeve set 108 comprises an uphole sliding sleeve 108A and a downhole sliding sleeve 108B, in some alternative embodiments as shown in
In these embodiments, the sleeve set 108 only comprise the downhole sliding sleeve 108B (simply denoted the sliding sleeve 108B hereinafter) which is initially secured by a shear pin (not shown) at an uphole position with a small distance to the uphole stopper 132 for closing the fracking ports 104. A gap 502 is thus formed between the sliding sleeve 108B and the downhole stopper 134.
As shown in
As shown in
As shown in
Then as shown in
As shown in
As shown in
As shown in
As shown in
As shown in
The downhole tool 100 in the embodiments shown in
In some embodiments related to those shown in
The J-slot 504 comprises an initial location P1 for engaging the J-pin when the sliding sleeve 108B is in the closed configuration. The location P1 is connected to an intermediate location P2 at a small distance downhole thereto, which in turn connected to an end position P3 at a large distance uphole thereto. Therefore, the initial location of the J-pin in position P1 prevents any downhole movement of the sliding sleeve 108B, thereby preventing the sliding sleeve 108B from being prematurely or accidentally actuated by a downward stroke to the open configuration and opening the fracking ports 104.
The transition of the J-pin from position P1 to P2 corresponds to the above-described uphole actuation of the sliding sleeve 108B for shearing the shear pin. The transition of the J-pin from position P2 to P3 corresponds to the above-described subsequent downhole actuation of the sliding sleeve 108B to the open configuration and opening the fracking ports 104.
In some embodiments, an indexing J-slot wrapping around the circumference of the sliding-sleeve 108B may be used for locking the sliding sleeve 108B at the open configuration for opening the plurality of ports. In some embodiments, such an indexing J-slot may comprise a plurality of positions for locking and preventing the sliding-sleeve 108B from moving uphole or downhole. The indexing J-slot may also have positions to allow the sliding sleeve 108B to at least partially open the fracking ports 104 in various stages (e.g., configuring the fracking ports 104 to fully open, 75% open, 50% open, or open to any other port-opening percentage, based on the position of the sleeve and determined by the profile of the indexing J-slot, thereby providing a choke or flow control. In these embodiments, the downhole sliding sleeve 108B is essentially a flow control device.
The sliding sleeve 108B also comprises a set of ratchet threads (not shown) about the uphole end thereof for engaging a set of ratchet threads (not shown) on the valve housing 122 about the uphole stopper 132.
The same actuation assembly 110 as described in above embodiments may be used for actuating the sliding sleeve 108B from the downhole closed position to the uphole open position.
As shown in
As shown in
With pressurized fluid 318 maintained, the actuation assembly 110 is further pulled uphole to shift the sliding sleeve 108B to the uphole open position. The ratchet threads of the sliding sleeve 108B then engage the ratchet threads of the valve housing 122 to lock the sliding sleeve 108B at the uphole open position.
As shown in
As shown in
After fracking, the actuation assembly 110 may be pulled uphole to reset the compressible sealing element 152 to its original uncompressed configuration and slide the actuation assembly 110 uphole to the next fracking location or to the surface.
In above embodiments, a plug 252 or ball 342 is used to block (fully or with a small amount of leak) the fluid communication between the bore of the actuation assembly 110 and the wellbore downhole thereto. In some alternative embodiments, a check valve such as a flapper valve may be used for blocking the fluid communication between the bore of the actuation assembly 110 and the wellbore downhole thereto.
Those skilled the art will appreciate that the apparatus, system, and method described in above embodiments are for illustrative purpose only, and variations and modifications are readily available, which in various embodiments, may be a combination and/or permutation of different structural components, method steps, features, and/or the like of the apparatus, system, and method described in above embodiments.
For example, in some embodiments, a method of fracking a subterranean formation about a section of a wellbore may comprise the steps of:
Although embodiments have been described above with reference to the accompanying drawings, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.
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| CA 3042542 | May 2019 | CA | national |
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