US20220049590A1

US20220049590A1 - Deployment tool & methodology for running and setting frac plugs and releasing frac balls

Info

Publication number: US20220049590A1
Application number: US17/400,987
Authority: US
Inventors: Dan S. DENNIS
Original assignee: Wildcat Oil Tools LLC
Current assignee: Wildcat Oil Tools LLC
Priority date: 2020-08-14
Filing date: 2021-08-12
Publication date: 2022-02-17

Abstract

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.

Description

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.

BRIEF DESCRIPTION OF THE DRAWINGS

The exemplary embodiments may be better understood, and numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. These drawings are used to illustrate only exemplary embodiments and are not to be considered limiting of its scope, for the disclosure may admit to other equally effective exemplary embodiments. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

FIG. 1 depicts a side view of an exemplary embodiment of a deployment wireline tool for running and setting a frac plug, wherein an outer sleeve of the tool is partially cut away or removed in the depiction.

FIG. 2 depicts a cross-section view of the exemplary embodiment of the deployment wireline tool of FIG. 1.

FIG. 3 depicts a cross-section view of an exemplary embodiment of a deployment wireline tool, without depiction of an outer sleeve, and wherein the frac plug is disengaged from the outer sleeve and an inner mandrel.

FIG. 4 depicts a cross-section view of an exemplary embodiment of the deployment wireline tool along line 4-4 in FIG. 3.

FIG. 5 depicts a side view of an exemplary embodiment of the deployment wireline tool and bottom hole assembly, wherein the frac plug has been set into the casing.

FIG. 5A depicts an enlarged cross-section side view of the exemplary embodiment of the deployment wireline tool in FIG. 5.

FIG. 6 depicts a side view of an exemplary embodiment of the deployment wireline tool and bottom hole assembly wherein the guns have fired and perforated the casing and the wellbore.

FIG. 6A depicts an enlarged cross-section side view of the exemplary embodiment of the deployment wireline tool in FIG. 6, wherein the frac ball is retained within the wireline tool during and after the successful firing of the guns.

FIG. 7 depicts a side view of an exemplary embodiment of the deployment wireline tool and bottom hole assembly wherein the pump is pumping an increased fluid flow rate above a predetermined flow rate, thus releasing the frac ball from the deployment wireline tool.

FIG. 7A depicts an enlarged cross-section side view of the exemplary embodiment of the deployment wireline tool in FIG. 7.

FIG. 8 depicts a side view of an exemplary embodiment of the released frac ball as set or engaged with the frac plug, wherein the exemplary embodiment of the deployment wireline tool and bottom hole assembly have been removed from the perforated casing and wellbore.

FIG. 9 depicts a side view of an exemplary embodiment of the released frac ball as set or engaged with the frac plug and isolating the zone uphole of the frac plug, wherein the pump is pumping fluid into the isolated zone and fracturing the perforations.

FIG. 10 depicts a cross-section view of an exemplary embodiment of the deployment wireline tool, wherein the frac ball is retained by one or more springs.

FIG. 11 depicts a cross-section view of an exemplary embodiment of the deployment wireline tool, wherein the frac ball is released from the one or more springs of FIG. 10.

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. 1 depicts a side view of an exemplary embodiment of a deployment wireline tool 10 for running and setting a frac plug 50, wherein an outer sleeve 13 of the running tool 10 is partially cut away to better depict the inner mandrel 20 within. FIG. 10 depicts a side cross-section view of an alternative exemplary embodiment of the tool 10, wherein the tool 10 has delivered or set the frac plug 50, and before release of the frac ball 30. The running and/or setting tool 10 may define an uphole end 11 and a downhole end 12. The uphole end 11 of the running tool 10 may further include an adjuster sub, a supporting member, coupler or other connector 15 which may support the inner mandrel 20 (see e.g. FIGS. 10s and 11) or, in alternative exemplary embodiments, connect the running tool 10 to other tools or parts of a bottom hole assembly (hereinafter, also referred to as “BHA”) 60. The adjuster sub 15 may ensure a proper fit and alignment of the components of BHA 60. A frac plug 50 may be connected or engaged at a downhole end 12 of the running tool 10.
The running tool 10 includes an outer sleeve 13 and an inner mandrel 20. In FIG. 1, part of the outer sleeve 13 is cut away or removed to better depict the interior of running tool 10. The outer sleeve 13 may define one or more outer sleeve flow or fluid ports, holes or openings 14. By way of example only, the outer sleeve 13 may have or define two or four ports 14; any number of ports 14 are considered within the scope of the disclosure. The inner mandrel 20 is located within the outer sleeve 13. The inner mandrel 20 may also define a first end 21 and a second end 22. The first end 21 of the inner mandrel 20 may be a substantially cylindrical body or portion 23, having a smaller outer diameter 23 a than the interior/inner diameter 13 a of that of the outer sleeve 13. The second end of the inner mandrel 20 may be a substantially tubular or cylindrical body or portion 25, wherein body 25 has a larger outer diameter 25 a than the inner mandrel cylindrical body 23 and which may complementarily fit within the outer sleeve 13. The first cylindrical body 23 and second cylindrical body 25 may be connected together via a frustoconical, angled or sloped shoulder 24 between the two bodies 23 and 25.
Referring at least to FIGS. 2-3, the inner mandrel 20 may further define a cavity or ball cavity 27 within the interior of the inner mandrel 20. The cavity 27 may be open at the second end 22 and extend at least partially into the first portion or body 23 of the inner mandrel 20. One or more inner mandrel fluid or flow ports, holes, or openings 26 may be defined on the first portion 23 of the inner mandrel 20, wherein each port or opening 26 is connected to the cavity 27. The openings 26 may be angled ports or openings, wherein the opening 26 is defined through the inner mandrel 20 at an angle 26 a to the longitudinal axis of the running tool 10, and connects to cavity 27 at an angle 26 a which is conducive to the movement of fluid 81 into the cavity 27 as pumped by pump 80. By way of example, and not to be limited to such, there may be three openings 26 distanced equally around the circumference or outer diameter 23 a of the first body portion 23 of the inner mandrel 20. The cavity 27 may have a larger or wider end 29 of the cavity 27, as located towards the second end 22 or the downhole end 12.
In a first orientation or position 10 a (see e.g. FIG. 10), the cavity 27 may house a ball, frack ball, frac ball, object or occluding object 30 (see further, e.g. FIGS. 1, 2, 5A, and 6A). The wireline tool 10 occupies the first position 10 a any time prior to the release of the frac ball 30. The cavity 27 may also partially house the first end 51 of the frac plug or isolation device 50. The frac plug 50 further defines a second end 52. A throughbore or through passage 57 is defined through the length of the frac plug 50. The throughbore 57 opens into a seat or ball seat 54 at the first end 51 of the frac plug 50. The ball seat 54 is complementary to the outer surface of the ball or occluding object 30, such that when the ball 30 is seated, plugged or engaged against the seat 54 and the frac plug 50 is set into the casing, no flow can occur through the passage 57. The frac plug 50 may also have a circumferential shoulder or extension 53 which may complementarily fit within the outer sleeve 13 when the running tool 10 is assembled.
The inner mandrel 20 and frac plug 50 may each define a series of shear pin openings 31 and 55, respectively. Shear pin openings 31 may be defined towards the second or downhole end 22 of the inner mandrel 20, in the widened portion 29 of the cavity 27. The shear pin openings 31 may allow for the fixture of the frac plug 50 and compression of the components of BHA 60 through the use or activation of shear pins or shear screws 56. Shear pin openings 55 may be defined towards the first or uphole end 51 and on the outer surface of the frac plug 50. Shear pins 56 may be inserted into shear pin openings 31 and shear pin openings 55 when same are aligned. The shear pins 56 may retain or secure the frac plug 50 into place within the cavity 27 while the BHA 60 is in the process of delivering the frac plug 50 to the desired location. The shear pins 56 are configured to break or shear when sufficient predetermined or preset force is applied to the inner mandrel 20 and outer sleeve 13.
The inner mandrel 20 further includes a number or a set of retention devices, springs or levers 40. As depicted in the figures, the springs 40 are attached to the exterior surface of the inner mandrel 20 on the frustoconical shoulder 24 and inserted into the cavity 27 through a spring opening 42 as defined on said shoulder 24. The springs 40 may be attached at a first end to the inner mandrel 20 via a fastener 41. The spring opening 42 should be large enough or wide enough to allow, by way of example only, at least a 20° angle deflection or flexibility of the flat spring 40 within the cavity 27. In an exemplary embodiment there may be three openings 26 and three springs 40 with the three openings 26 respectively generally aligned to direct flow pressure to the three springs 40. In further alternative exemplary embodiments, the spring 40 may instead be attached (via fasteners 41 or other means as known in the art) to the interior surface of the cavity 27, while allowing for the same or similar amount of angle of deflection in the spring 40. Other desired angles of deflection, thickness, material, length and strength in the spring 40 may be selected as desired by the operator of the system. An exemplary embodiment of the springs 40 and shear pin openings 31 as located on the inner mandrel 20 is depicted in FIG. 4.
When assembled with the frack plug, frac plug, mandrel plug, or isolation device 50 for running said frac plug 50 to the desired location or destination, the free end or unattached end of the springs or retention devices 40 may be located or situated in between the ball 30 and the ball seat 54. The free or unattached end of the springs 40 may optionally feature a means of retention such as a tab, hook, curve or lip 43 which further supports, retains or cages the ball 30 before the ball 30 is released via a preset flow rate 81 from the pump 80. As depicted in at least FIG. 2, a portion of the springs 40 and/or the spring tabs/hooks 43 may prevent the ball 30 from seating or engaging fully with the seat 54 such that there is a gap 32 allowing fluid to flow around the sides of the ball 30 and through the seat 54 and the throughbore 57 of the frac plug 50. The profile of the spring 40 may optionally include further irregularities such as additional curves, curls, crimps/kinks/angles or other geometry to facilitate fluid flow through the gap 32 while retaining and supporting the ball 30 within the cage formed by the springs 40. In further exemplary embodiments, the spring 40 may retain the ball 30 without the hook 43 or any other profile irregularities. The fluid 81 may be pumped or motivated via the pump 80 both before and after the frac plug 50 is set into the casing 61.
In a first position 10 a of the deployment wireline tool 10, wherein the springs 40 are containing, retaining or securing the ball 30, (by way of example, as depicted in at least FIGS. 1 and 10), the ball 30 is fully housed within the cavity 27 of the inner mandrel 20. The ball 30, as described above, may be in contact with or supported the springs 40 on an underside of the ball 30. The top of ball 30 may be in contact with or supported by an interior shoulder or extension 28 extended from the interior wall of the cavity 27. The frac plug 50 may or may not be within the deployment wireline tool 10 in the first position 10 a (as it may have already been set into the casing 61). In a second position 10 b of the deployment wireline tool 10, (by way of example, as depicted in at least FIGS. 7A and 11) wherein the springs 40 have released the ball 30, the ball 30 is free to move with any pumped fluid flow 81 and may no longer be in contact with the interior shoulder 28, the springs 40 and the spring hooks 43.
Once the deployment wireline tool 10 is at the desired location within the wellbore 63 (or other subterranean environment or location 63) for the frac plug 50, the tool 10 of BHA 60, carrying the ball or occluding object 30 within the cavity 27, is manipulated and powered through the wireline 62 to apply a sufficient pulling force on the inner mandrel 20 and/or a sufficient pushing force on the outer sleeve 13. As a result, the shear pins 56 are broken or sheared, and the frac plug 50 separates from the inner mandrel 20 and sets or engages into the casing 61 (or other subterranean environment) at the desired location. Subsequently, the FIGS. 5-9 depict the process of flow actuated release or releasing of the frac ball 30 after the setting of the frac plug 50. In FIGS. 5 and 5A, the frac plug or isolation device 50 of the bottom hole assembly 60 has been set via the wireline 62 into the casing 61 within the wellbore 63. Further, the bottom hole assembly or BHA 60 has been pulled, retracted or relocated uphole via wireline 62 to the desired or selected position within the wellbore 63 for the one or more guns 70 to perforate. In FIGS. 5 and 5A, the ball 30 is retained in the cavity 27 and supported or retained by the springs 40 and the interior shoulder 28 of the cavity 27. In FIGS. 6 and 6A, the operator has fired or powered the guns 70 via wireline 62 to puncture the casing 61 and wellbore 63 with perforations 71. The ball 30 is still retained within the cavity 27 by the springs 40 in FIGS. 2, 6 and 6A. In FIGS. 7 and 7A, the operator may now set, via pump 80, an increased fluid flow rate, as shown by arrows 81, to flow around the guns 70 and other portions of the bottom hole assembly 60 to the running tool 10. The flow of the fluid 81 may travel through the outer sleeve ports 14 to the inner mandrel ports 26 and into the ball cavity 27 and towards the springs 40. Each of the springs 40 have sufficient strength, thickness or stiffness to resist a flow rate 81 below the predetermined range or amount. As a result, the set of springs 40 retains the ball or object 30 within the cavity 27 when the flow of the fluid 81 from the pump 80 is below such a predetermined or preset rate (as shown in FIGS. 1-3, and 5-6A). By way of example only, the springs 40 may resist release of the ball 30 when the flow rate 81 is less than 5 gallons per minute. In an exemplary embodiment, when the flow rate 81 is between 5 to 10 gallons per minute or between 5 to 10 barrels per minute, or greater, the flow 81 may have sufficient force, pressure or strength to push or force the ball 30 against and deflect the springs 40 away from the bottom of the ball 30. The fluid pressure required to release the ball 30 (i.e. overcome the springs 40) is adjustable or dependent relative to the spring force. As the unattached ends of the springs 40 angle towards the interior of the cavity 27 during deflection, the ball 30 is released (as depicted in FIGS. 7A and 11). The operator thus can command the release of the ball 30 as desired by adjusting the flow rate 81 above or below the preset flow rate accordingly.
The fluid 81, as delivered by pump 80, continues to flow through cavity 27 to the throughbore 57 of the frac plug or isolation device 50. The ball 30, after release from the springs 40, travels with the fluid 81 to land, set or engage on or with the ball seat 54 on the frac plug 50, as seen in FIG. 8. As depicted in FIG. 9, once the ball 30 is seated on the seat 54, fluid flow is blocked/prevented through the passage 57, and additional fluid may be pumped via pump 80 to create one or more fractures 64 through the one or more perforations 71 in the wellbore 63, thus inducing or stimulating production in said wellbore 63. In essence the pump controller/operator has flexibility in determining when (i.e. the timing) and commanding release of the ball 30.
If one or more of the guns 70 misfire, or in the case of any other malfunction, or under any circumstance as desired by the operator of the system, so long as the fluid 81 has not been pumped to the wireline tool 10 at or above the predetermined flow rate, the BHA 60 having retained the frac ball 30 may be retrieved and a replacement redeployed to the desired location within the wellbore 63. 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 ball 30 by directing, controlling or manipulating the flow of fluid 81 from the pump 80, preventing the ball 30 from inadvertently, accidentally, or prematurely releasing and blocking the flow of fluid into wellbore 63 and past the frac plug 50. Without a ball 30 blocking pressure or fluid flow in the wellbore 63/casing 61, the BHA 60 may 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 tool 10 and BHA 60 are frequently depicted and described herein as within a casing 61 and or wellbore 64, 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.
Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter.

Claims

1. A method for deploying a frac ball within a subterranean location, comprising 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.

2. The method according to claim 1, further comprising the step of releasing the frac ball from the cavity when the fluid is pumped above the predetermined flow rate.

3. The method according to claim 2, wherein the step of retaining the frac ball in the cavity is performed by one or more retention devices retaining the ball within the cavity.

4. The method according to claim 3, wherein the predetermined flow rate is five gallons per minute.

5. The method according to claim 4, further comprising the step of deflecting an end of each of the one or more retention devices away from an underside of the ball in the cavity before the step of releasing the frac ball from the cavity.

6. The method according to claim 5, further comprising the step of preventing the frac ball from release after the firing fewer than all of the one or more guns.

7. The method according to claim 6, further comprising the step of retrieving the wireline tool and the frac ball from the subterranean location.

8. The method according to claim 6, further comprising the step of seating the frac ball into a seat of the frac plug.

9. The method according to claim 8, wherein the wireline tool comprises at least an outer sleeve and an inner mandrel, and wherein the cavity is located within the inner mandrel.

10. The method according to claim 9, wherein the step of setting the frac plug into the subterranean location further comprises the steps of applying a pushing force to the outer sleeve; applying a pulling force to the inner mandrel; and shearing one or more shear pins connected to the frac plug.

11. The method according to claim 10, wherein the step of firing one or more guns into the subterranean location comprises the step of creating one or more perforations in the subterranean location.

12. The method according to claim 11, further comprising the steps of preventing fluid flow through the frac plug; forcing fluid through the one or more perforations;

and creating fractures in the subterranean location.

13. A wireline deployment tool for release of a frac ball comprising:

a cavity defined within the wireline deployment tool;

wherein the frac ball is housed within the cavity; and

a retention device attached at a first end to a wall of the cavity, and wherein a second end of the retention device is unattached and releasably engaged with the frac ball.

14. The wireline deployment tool according to claim 13, wherein the retention device is configured to resist deflection if a fluid flow rate is below five gallons per minute.

15. The wireline deployment tool according to claim 14, further comprising

an outer sleeve housing an inner mandrel; and

wherein the cavity is located within the inner mandrel.

16. The wireline deployment tool according to claim 15, further comprising

a first fluid port defined on the outer sleeve; and

a second fluid port defined on the inner mandrel.

17. The wireline deployment tool according to claim 16, wherein the second fluid port is defined at an angle through the inner mandrel.

18. The wireline deployment tool according to claim 17, wherein the retention device is flexible to an angle of deflection of 20°.

19. The wireline deployment tool according to claim 18, further comprising a frac plug connected to the inner mandrel.

20. The wireline deployment tool according to claim 19, wherein the retention device comprises at least three retention devices.

21. A method for controlled release of a frac ball within a subterranean environment, comprising the steps of:

running a wireline tool downhole into the subterranean environment, wherein the frac ball is housed within the wireline tool;

pumping a fluid downhole at a current flow rate;

preventing the release of the frac ball from the wireline tool when the current flow rate is below a preselected flow rate;

increasing the current flow rate to the preselected flow rate and then releasing the frac ball from the wireline tool; and

seating the frac ball into a frac plug set within the subterranean location.