DEPLOYMENT TOOL & METHODOLOGY FOR RUNNING AND SETTING FRAC PLUGS AND RELEASING FRAC BALLS

The disclosure relates to a method for deploying a frac ball within a subterranean location, having the steps of: deploying a wireline tool into the subterranean location, wherein the wireline tool defines a cavity housing the frac ball; pumping a fluid into the subterranean location; retaining the frac ball in the cavity while the fluid is pumped below a predetermined flow rate; setting a frac plug into the subterranean location; and firing one or more guns into the subterranean location.

STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not Applicable.

BACKGROUND

Technical Field: The disclosure relates to the field of plug and perforate processes in the petrochemical industry, in particular, devices and methods relating to the release or delivery of a frac ball or other occluding object onto a seat of a frac plug, after setting the frac plug into place.

In conventionally known plug and perforate systems, a bottom hole assembly (also referred to herein as “BHA”) may include one or more perforating guns, a plug setting tool, and a frac plug or isolation device. Some BHAs may optionally further include a ball release tool. The BHA delivers and sets a frac plug or isolation device at a desired location within the casing. The frac plug or isolation device typically has a throughbore which may be blocked or plugged with a frac ball or other object. A first known conventional means of delivering the frac ball include setting the frac plug, then firing the guns to perforate the well, and then dropping the frac ball through the casing and delivering the frac ball to the ball seat on the frac plug. This method of conveying the ball requires valuable time, fuel and fluid, which results in a relatively large environmental footprint. A second known conventional means of delivering the frac ball includes simultaneously carrying the frac ball and frac plug to the desired location, which is a comparatively smaller environmental footprint compared to the first known conventional means but is problematic when the perforating guns have misfired and the frac ball has nonetheless been inserted into the seat of the frac plug. In this scenario, the seating of the frac ball in the frac plug prevents the wireline from easily or efficiently running replacement guns. Effective or desired pumping is inhibited with the frac ball set into the seat of the frac plug if the guns are misfiring. To resume normal oilfield operations, a handful of processes may be used to unseat the frac ball or object from the frac plug seat and redeliver the BHA to the desired position. All of these corrective measures are generally expensive in terms of cost, operational delay and/or needed equipment and resources. US Patent Publication No. 20150252643, which is herein incorporated by reference in its entirety, proposes a device and method of automatic release of the frac ball upon the successful firing of at least one perforating gun, wherein the pressure released from the fired gun causes the release of the frac ball. However, the devices and methods under US20150252643 do not allow for precise operator control of when the frac ball is released. By way of example, the firing of any one gun may generate sufficient pressure for the frac ball to automatically release and engage the frac plug. In essence the frac ball may be automatically released regardless of whether the gun(s) fire correctly or misfire. The firing of less than all of the perforating guns may not be sufficient to proceed with additional fracturing activities, despite the automatic release of the frac ball. Thus, it may still be necessary to run replacement guns into the casing, but because the frac ball automatically seated onto the frac plug, this presents the same or similar problems as identified before. Additionally, the technology involved in perforating the casing is continually changing, including charge shaping, penetration depth and amount of explosive charge. When the amount of explosive charge is reduced but the penetration depth is the unchanged, these conventional methods may result in increased risk of failure of rupturing the fluid pathways. Hence mitigation would be required, and downhole mitigation takes up valuable rig time. Thus, a need exists for an improved device and method for a running tool and controlled frac ball release.

BRIEF SUMMARY

The disclosure relates to a method for deploying a frac ball within a subterranean location, having the steps of: deploying a wireline tool into the subterranean location, wherein the wireline tool defines a cavity housing the frac ball; pumping a fluid into the subterranean location; retaining the frac ball in the cavity while the fluid is pumped below a predetermined flow rate; setting a frac plug into the subterranean location; and firing one or more guns into the subterranean location.

As used herein, the terms “frac” or “frack” also includes encompasses the terms “fracture”, “fracturing”, “fracking”, “fracing”, or fraccing or “hydraulic fracturing” as commonly understood in the petrochemical field.

DESCRIPTION OF EMBODIMENT(S)

The description that follows includes exemplary apparatus, methods, techniques, and instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

FIG. 1depicts a side view of an exemplary embodiment of a deployment wireline tool10for running and setting a frac plug50, wherein an outer sleeve13of the running tool10is partially cut away to better depict the inner mandrel20within.FIG. 10depicts a side cross-section view of an alternative exemplary embodiment of the tool10, wherein the tool10has delivered or set the frac plug50, and before release of the frac ball30. The running and/or setting tool10may define an uphole end11and a downhole end12. The uphole end11of the running tool10may further include an adjuster sub, a supporting member, coupler or other connector15which may support the inner mandrel20(see e.g.FIGS. 10sand11) or, in alternative exemplary embodiments, connect the running tool10to other tools or parts of a bottom hole assembly (hereinafter, also referred to as “BHA”)60. The adjuster sub15may ensure a proper fit and alignment of the components of BHA60. A frac plug50may be connected or engaged at a downhole end12of the running tool10.

The running tool10includes an outer sleeve13and an inner mandrel20. InFIG. 1, part of the outer sleeve13is cut away or removed to better depict the interior of running tool10. The outer sleeve13may define one or more outer sleeve flow or fluid ports, holes or openings14. By way of example only, the outer sleeve13may have or define two or four ports14; any number of ports14are considered within the scope of the disclosure. The inner mandrel20is located within the outer sleeve13. The inner mandrel20may also define a first end21and a second end22. The first end21of the inner mandrel20may be a substantially cylindrical body or portion23, having a smaller outer diameter23athan the interior/inner diameter13aof that of the outer sleeve13. The second end of the inner mandrel20may be a substantially tubular or cylindrical body or portion25, wherein body25has a larger outer diameter25athan the inner mandrel cylindrical body23and which may complementarily fit within the outer sleeve13. The first cylindrical body23and second cylindrical body25may be connected together via a frustoconical, angled or sloped shoulder24between the two bodies23and25.

Referring at least toFIGS. 2-3, the inner mandrel20may further define a cavity or ball cavity27within the interior of the inner mandrel20. The cavity27may be open at the second end22and extend at least partially into the first portion or body23of the inner mandrel20. One or more inner mandrel fluid or flow ports, holes, or openings26may be defined on the first portion23of the inner mandrel20, wherein each port or opening26is connected to the cavity27. The openings26may be angled ports or openings, wherein the opening26is defined through the inner mandrel20at an angle26ato the longitudinal axis of the running tool10, and connects to cavity27at an angle26awhich is conducive to the movement of fluid81into the cavity27as pumped by pump80. By way of example, and not to be limited to such, there may be three openings26distanced equally around the circumference or outer diameter23aof the first body portion23of the inner mandrel20. The cavity27may have a larger or wider end29of the cavity27, as located towards the second end22or the downhole end12.

In a first orientation or position10a(see e.g.FIG. 10), the cavity27may house a ball, frack ball, frac ball, object or occluding object30(see further, e.g.FIGS. 1, 2, 5A, and6A). The wireline tool10occupies the first position10aany time prior to the release of the frac ball30. The cavity27may also partially house the first end51of the frac plug or isolation device50. The frac plug50further defines a second end52. A throughbore or through passage57is defined through the length of the frac plug50. The throughbore57opens into a seat or ball seat54at the first end51of the frac plug50. The ball seat54is complementary to the outer surface of the ball or occluding object30, such that when the ball30is seated, plugged or engaged against the seat54and the frac plug50is set into the casing, no flow can occur through the passage57. The frac plug50may also have a circumferential shoulder or extension53which may complementarily fit within the outer sleeve13when the running tool10is assembled.

The inner mandrel20and frac plug50may each define a series of shear pin openings31and55, respectively. Shear pin openings31may be defined towards the second or downhole end22of the inner mandrel20, in the widened portion29of the cavity27. The shear pin openings31may allow for the fixture of the frac plug50and compression of the components of BHA60through the use or activation of shear pins or shear screws56. Shear pin openings55may be defined towards the first or uphole end51and on the outer surface of the frac plug50. Shear pins56may be inserted into shear pin openings31and shear pin openings55when same are aligned. The shear pins56may retain or secure the frac plug50into place within the cavity27while the BHA60is in the process of delivering the frac plug50to the desired location. The shear pins56are configured to break or shear when sufficient predetermined or preset force is applied to the inner mandrel20and outer sleeve13.

The inner mandrel20further includes a number or a set of retention devices, springs or levers40. As depicted in the figures, the springs40are attached to the exterior surface of the inner mandrel20on the frustoconical shoulder24and inserted into the cavity27through a spring opening42as defined on said shoulder24. The springs40may be attached at a first end to the inner mandrel20via a fastener41. The spring opening42should be large enough or wide enough to allow, by way of example only, at least a 20° angle deflection or flexibility of the flat spring40within the cavity27. In an exemplary embodiment there may be three openings26and three springs40with the three openings26respectively generally aligned to direct flow pressure to the three springs40. In further alternative exemplary embodiments, the spring40may instead be attached (via fasteners41or other means as known in the art) to the interior surface of the cavity27, while allowing for the same or similar amount of angle of deflection in the spring40. Other desired angles of deflection, thickness, material, length and strength in the spring40may be selected as desired by the operator of the system. An exemplary embodiment of the springs40and shear pin openings31as located on the inner mandrel20is depicted inFIG. 4.

When assembled with the frack plug, frac plug, mandrel plug, or isolation device50for running said frac plug50to the desired location or destination, the free end or unattached end of the springs or retention devices40may be located or situated in between the ball30and the ball seat54. The free or unattached end of the springs40may optionally feature a means of retention such as a tab, hook, curve or lip43which further supports, retains or cages the ball30before the ball30is released via a preset flow rate81from the pump80. As depicted in at leastFIG. 2, a portion of the springs40and/or the spring tabs/hooks43may prevent the ball30from seating or engaging fully with the seat54such that there is a gap32allowing fluid to flow around the sides of the ball30and through the seat54and the throughbore57of the frac plug50. The profile of the spring40may optionally include further irregularities such as additional curves, curls, crimps/kinks/angles or other geometry to facilitate fluid flow through the gap32while retaining and supporting the ball30within the cage formed by the springs40. In further exemplary embodiments, the spring40may retain the ball30without the hook43or any other profile irregularities. The fluid81may be pumped or motivated via the pump80both before and after the frac plug50is set into the casing61.

In a first position10aof the deployment wireline tool10, wherein the springs40are containing, retaining or securing the ball30, (by way of example, as depicted in at leastFIGS. 1 and 10), the ball30is fully housed within the cavity27of the inner mandrel20. The ball30, as described above, may be in contact with or supported the springs40on an underside of the ball30. The top of ball30may be in contact with or supported by an interior shoulder or extension28extended from the interior wall of the cavity27. The frac plug50may or may not be within the deployment wireline tool10in the first position10a(as it may have already been set into the casing61). In a second position10bof the deployment wireline tool10, (by way of example, as depicted in at leastFIGS. 7A and 11) wherein the springs40have released the ball30, the ball30is free to move with any pumped fluid flow81and may no longer be in contact with the interior shoulder28, the springs40and the spring hooks43.

Once the deployment wireline tool10is at the desired location within the wellbore63(or other subterranean environment or location63) for the frac plug50, the tool10of BHA60, carrying the ball or occluding object30within the cavity27, is manipulated and powered through the wireline62to apply a sufficient pulling force on the inner mandrel20and/or a sufficient pushing force on the outer sleeve13. As a result, the shear pins56are broken or sheared, and the frac plug50separates from the inner mandrel20and sets or engages into the casing61(or other subterranean environment) at the desired location. Subsequently, theFIGS. 5-9depict the process of flow actuated release or releasing of the frac ball30after the setting of the frac plug50. InFIGS. 5 and 5A, the frac plug or isolation device50of the bottom hole assembly60has been set via the wireline62into the casing61within the wellbore63. Further, the bottom hole assembly or BHA60has been pulled, retracted or relocated uphole via wireline62to the desired or selected position within the wellbore63for the one or more guns70to perforate. InFIGS. 5 and 5A, the ball30is retained in the cavity27and supported or retained by the springs40and the interior shoulder28of the cavity27. InFIGS. 6 and 6A, the operator has fired or powered the guns70via wireline62to puncture the casing61and wellbore63with perforations71. The ball30is still retained within the cavity27by the springs40inFIGS. 2, 6 and 6A. InFIGS. 7 and 7A, the operator may now set, via pump80, an increased fluid flow rate, as shown by arrows81, to flow around the guns70and other portions of the bottom hole assembly60to the running tool10. The flow of the fluid81may travel through the outer sleeve ports14to the inner mandrel ports26and into the ball cavity27and towards the springs40. Each of the springs40have sufficient strength, thickness or stiffness to resist a flow rate81below the predetermined range or amount. As a result, the set of springs40retains the ball or object30within the cavity27when the flow of the fluid81from the pump80is below such a predetermined or preset rate (as shown inFIGS. 1-3, and 5-6A). By way of example only, the springs40may resist release of the ball30when the flow rate81is less than 5 gallons per minute. In an exemplary embodiment, when the flow rate81is between 5 to 10 gallons per minute or between 5 to 10 barrels per minute, or greater, the flow81may have sufficient force, pressure or strength to push or force the ball30against and deflect the springs40away from the bottom of the ball30. The fluid pressure required to release the ball30(i.e. overcome the springs40) is adjustable or dependent relative to the spring force. As the unattached ends of the springs40angle towards the interior of the cavity27during deflection, the ball30is released (as depicted inFIGS. 7A and 11). The operator thus can command the release of the ball30as desired by adjusting the flow rate81above or below the preset flow rate accordingly.

The fluid81, as delivered by pump80, continues to flow through cavity27to the throughbore57of the frac plug or isolation device50. The ball30, after release from the springs40, travels with the fluid81to land, set or engage on or with the ball seat54on the frac plug50, as seen inFIG. 8. As depicted inFIG. 9, once the ball30is seated on the seat54, fluid flow is blocked/prevented through the passage57, and additional fluid may be pumped via pump80to create one or more fractures64through the one or more perforations71in the wellbore63, thus inducing or stimulating production in said wellbore63. In essence the pump controller/operator has flexibility in determining when (i.e. the timing) and commanding release of the ball30.

If one or more of the guns70misfire, or in the case of any other malfunction, or under any circumstance as desired by the operator of the system, so long as the fluid81has not been pumped to the wireline tool10at or above the predetermined flow rate, the BHA60having retained the frac ball30may be retrieved and a replacement redeployed to the desired location within the wellbore63. Unlike the prior art or other conventionally known devices and methods, with the exemplary embodiments described herein, the operator may control or command the timing of the release of the frac ball30by directing, controlling or manipulating the flow of fluid81from the pump80, preventing the ball30from inadvertently, accidentally, or prematurely releasing and blocking the flow of fluid into wellbore63and past the frac plug50. Without a ball30blocking pressure or fluid flow in the wellbore63/casing61, the BHA60may be easily retrieved and redeployed using commonly known, inexpensive mitigation techniques and with relatively minor setback to the overall operation.

While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions, and improvements are possible. By way of example only, although the deployment wireline tool10and BHA60are frequently depicted and described herein as within a casing61and or wellbore64, it is to be appreciated that same or similar exemplary embodiments of the devices and processes disclosed within may be applied to any subterranean location or environment.