Piston Rod

Abstract

A setting tool that sets a packer or bridge plug in a wellbore using an improved piston rod design.

Claims

1. A piston assembly for a setting tool comprising: a substantially cylindrical piston head 12 that is rotationally symmetrical about an axis and having an inner bore 17 extending from a lower face 50 of the piston head 12 partially into the piston head 12 toward an upper face 51 of the piston head 12 along the axis; and a piston rod having a threaded portion 19 threadably engaged in the inner bore and an elongated portion extending away from the piston head.

2. The piston assembly of claim 1 further comprising a threaded portion and a thread relief portion 18 of the inner bore having no threads between the threaded portion of the inner bore and the lower face.

3. The piston assembly of claim 2 wherein the threaded portion of the inner bore has a maximum diameter corresponding to the relief portion of the threads and the thread relief portion of the inner bore has a diameter larger than the maximum diameter of the threaded portion of the inner bore.

4. The piston assembly of claim 3 further comprising a set screw bore and corresponding set screw in the piston head extending radially from the thread relief portion of the inner bore.

5. The piston assembly of claim 1 further comprising a set screw bore and corresponding set screw in the piston head extending radially from the inner bore.

6. The piston assembly of claim 1 further comprising a first o-ring groove 16 about a circumference of the piston head.

7. The piston assembly of claim 1 further comprising a plurality of o-ring grooves 16 about a circumference of the piston head.

8. The piston assembly of claim 1 wherein the piston rod further comprises a slot 52 distal from the threaded portion 19 adapted to engage a crosslink 28.

9. A setting tool comprising: a lower cylinder 30; a substantially cylindrical piston head 12 within lower cylinder 30 that is rotationally symmetrical about an axis and having a threaded inner bore extending from a lower face 50 of the piston head partially into the piston head toward an upper face 51 of the piston head along the axis; a piston rod having a threaded portion 19 threadably engaged in the inner bore and an elongated portion extending away from the piston head; a mandrel extending from the lower cylinder away from the piston head; a crosslink sleeve 29 slideably engaged around the mandrel; a crosslink 28 coupling the elongated portion of the piston rod to the crosslink sleeve; and wherein movement of the piston head causes relative movement between the mandrel 35 and the crosslink sleeve 29.

10. The setting tool of claim 9 further comprising a threaded portion and a thread relief portion of the inner bore having no threads between the threaded portion of the inner bore and the lower face.

11. The setting tool of claim 10 wherein the threaded portion of the inner bore has a maximum diameter corresponding to the relief portion of the threads and the thread relief portion of the inner bore has a diameter larger than the maximum diameter of the threaded portion of the inner bore.

12. The setting tool of claim 11 further comprising a set screw bore and corresponding set screw in the piston head extending radially from the thread relief portion of the inner bore.

13. The setting tool of claim 9 further comprising a set screw bore and corresponding set screw in the piston head extending radially from the inner bore.

14. The setting tool of claim 9 further comprising a first o-ring groove about a circumference of the piston head.

15. The setting tool of claim 9 wherein the piston rod further comprises a slot 52 distal from the threaded portion 19 adapted to engage a crosslink 28.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference numbers designate like or similar elements throughout the several figures of the drawing. Briefly:

[0022] FIG. 1 depicts a cross-sectional side view of a piston rod.

[0023] FIG. 2A depicts a cross-sectional side view of a setting tool.

[0024] FIG. 2B depicts a close-up of a cross-section side view of a lower piston on a setting tool.

[0025] FIG. 3A depicts a cross-sectional side view of a tool string after setting.

[0026] FIG. 3B depicts a close-up of a cross-section side view of a lower piston on a setting tool.

DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION

[0027] In the following description, certain terms have been used for brevity, clarity, and examples. No unnecessary limitations are to be implied therefrom and such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus, systems and method steps described herein may be used alone or in combination with other apparatus, systems and method steps. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims.

[0028] An example embodiment may include a cablehead assembly which has a wireline coupled to the uphole end of a fish neck assembly. A casing collar locator, sometimes abbreviated CCL, is located downhole from and coupled to the downhole end of the fish neck assembly. A quick change assembly is located downhole from and coupled to the downhole end of the casing collar locator assembly. A firing head assembly is located downhole from and coupled to the downhole end of the quick change assembly. A setting tool assembly is located downhole from and coupled to the downhole end of the firing head assembly. The downhole end of the setting tool assembly is coupled to a setting sleeve and a tension mandrel. The tension mandrel is coupled to a bridge plug using a shear stud.

[0029] In operation the operator sends a signal through the wireline, which causes the firing head assembly to ignite a chemical power charge. The expanding gas generated from the power charge causes the setting tool assembly to mechanically extend in such a way that the setting sleeve moves downhole relative to a tension mandrel, which stays stationary. The setting sleeve mechanically collapses a bridge plug, or other expandable completions tool, which causes it to expand and seal off the casing at a desired location in which the tool string is located. After the bridge plug is expanded, sufficient stress builds up in a shear stud to cause it to separate from the bridge plug. Once separated, the rest of the tool string can be moved uphole while the bridge plug stays in place in the casing. In addition to a bridge plug, the setting tool can be used to expand or plug a variety of downhole completions equipment at desired locations within the borehole.

[0030] Referring to FIG. 1, a setting tool uses a piston assembly 10 to convert a working fluid, such as gas or fluid, pressure into a mechanical longitudinal motion for setting a packer. The working fluid acts on the piston head 12. The piston head 12 has an inner bore 17 with threads 15 and a thread relief 18. Inner bore 17 is located partially in the piston head 12, starting from inner face 50 and extending to the upper face 51. O-ring grooves 16 allow for one or more o-rings to seal the piston head 12 within a cylinder. A piston rod 11 has a threaded portion 19 that screws into the threads 15 of the piston head 12. Piston rod 11 has a slot 52 adapted for engaging with a crosslink. This threaded couple allows for the piston to be rigidly engaged and held to a closer concentric tolerance than previous designs. The force acting on the piston head 12 is transferred to the distal end. The threaded portion 19 and the threads 15 prevent the piston rod from moving axially off center. The threaded couple reduces bending forces in the piston rod 11, thereby preventing failures and deformation of the piston rod 11. Bending of the elongated portion 20 of the piston rod 11 may cause failure which may result in an incomplete setting job. Another problem of piston rod bending is that it can cause the piston assembly 10 to get stuck in the cylinder. Piston rod bending or failure could also damage the rest of the setting tool, thus negatively impacting the reusability of the setting tool.

[0031] Referring to FIG. 2A, a cross-section of the setting tool assembly 100 is shown in a pre-setting configuration, prior to coupling with additional tool string components and prior to placement downhole. A power charge chamber 21 is located uphole from and coupled to the ported bleeder sub 22. The ported bleeder sub 22 is located uphole from and coupled to the upper cylinder housing 32. The inner bore of upper cylinder housing 32 forms upper cylinder 24. The upper piston 23 is slideably engaged with the upper cylinder 24. The upper cylinder housing 32 is uphole from and coupled to the tandem connector 25. Generally the upper cylinder 24 will contain a working fluid, such as a hydraulic fluid, between the upper piston 23 and the tandem connector 25. The tandem connector 25 contains a metering fluid passageway 33 for regulating the flow of the working fluid through the tandem connector 25. The tandem connector 25 is located uphole from and coupled to the lower cylinder housing 34. The inner bore of the lower cylinder housing 34 forms a lower cylinder 30.

[0032] Still referring to FIG. 2A, a piston rod assembly 10 is slideably disposed within the lower cylinder 30. The piston rod assembly 10 includes a piston head 12 and a piston rod 11. The piston rod head 12 is slideably engaged with the lower cylinder 30. The piston rod 11 is slideably engaged with the cylinder head 26. The piston rod 11 is engaged with and coupled to the crosslink 28 via slot 52 and held in place using crosslink retaining ring 31. The crosslink 28 is engaged with and coupled to the crosslink sleeve 29. The crosslink sleeve 29 is slideably engaged over mandrel 35. Mandrel 35 is static as the cross link sleeve 29 slides longitudinally downhole when the setting tool assembly 100 is engaged. This allows the setting tool assembly 100 to push downward on the exterior of a packer while holding the interior of the packer, forcing the packer to expand radially and engage against the borehole.

[0033] Referring to FIG. 2B, a close up of the piston rod assembly 10 located within the setting tool assembly 100, a piston rod assembly 10 is slideably disposed within the lower cylinder 30. The piston rod assembly 10 includes a piston head 12 and a piston rod 11. The piston rod head 12 is slideably engaged with the lower cylinder 30. The piston rod 11 is slideably engaged with the cylinder head 26. The piston rod 11 is engaged with and coupled to the crosslink 28 via slot 52 and held in place using crosslink retaining ring 31. The crosslink 28 is engaged with and coupled to the crosslink sleeve 29. The crosslink sleeve 29 is slideably engaged over mandrel 35.

[0034] Referring to FIG. 3A, a cross-section of the setting tool assembly 100 is shown in a post-setting configuration. A power charge chamber 21 is located uphole from and coupled to the ported bleeder sub 22. The ported bleeder sub 22 is located uphole from and coupled to the upper cylinder housing 32. The inner bore of upper cylinder housing 32 forms upper cylinder 24. The upper piston 23 is slideably engaged with the upper cylinder 24. The upper cylinder housing 32 is uphole from and coupled to the tandem connector 25. Generally the upper cylinder 24 will contain a working fluid, such as a hydraulic fluid, between the upper piston 23 and the tandem connector 25. The tandem connector 25 contains a metering fluid passageway 33 for regulating the flow of the working fluid through the tandem connector 25. The tandem connector 25 is located uphole from and coupled to the lower cylinder housing 34. The inner bore of the lower cylinder housing 34 forms a lower cylinder 30.

[0035] Still referring to FIG. 3A, a piston rod assembly 10 is slideably disposed within the lower cylinder 30. The piston rod assembly 10 includes a piston head 12 and a piston rod 11. The piston rod head 12 is slideably engaged with the lower cylinder 30. The piston rod 11 is slideably engaged with the cylinder head 26. The piston rod 11 is engaged with and coupled to the crosslink 28 via slot 52 and held in place using crosslink retaining ring 31. The crosslink 28 is engaged with and coupled to the crosslink sleeve 29. The crosslink sleeve 29 is slideably engaged over mandrel 35. Mandrel 35 is static as the cross link sleeve 29 slides longitudinally downhole when the setting tool assembly 100 is engaged. In this post-setting configuration the working fluid has pushed the piston assembly 10 downhole until it bottoms out against the cylinder head 26. This results in the crosslink sleeve 29 moving downhole, with the mandrel 35, slideably disposed within the crosslink sleeve 29, remaining stationary. The end result is a combination of pushing and holding that allows for the setting of a bridge plug, packer, or other expandable completion tool.

[0036] Referring to FIG. 3B, a close up of the piston rod assembly 10 located within the setting tool assembly 100 after the setting tool assembly 100 has been engaged. A piston rod assembly 10 is slideably disposed within the lower cylinder 30. The piston rod assembly 10 includes a piston head 12 and a piston rod 11. The piston rod head 12 is slideably engaged with the lower cylinder 30. The piston rod 11 is slideably engaged with the cylinder head 26. The piston rod 11 is engaged with and coupled to the crosslink 28 via slot 52 and held in place using crosslink retaining ring 31. The crosslink 28 is engaged with and coupled to the crosslink sleeve 29. The crosslink sleeve 29 is slideably engaged over mandrel 35.

[0037] Operating the described embodiment includes assembling the tool string, lowering it into a wellbore, using, for example, the casing collar locator assembly to accurately determine the position of the tool string, positioning a bridge plug, packer, or other expandable at a desired location within the wellbore, igniting the power charge via a signal from the wireline to the firing head assembly, extending the setting tool assembly 100 using the gases from the power charge, setting the bridge plug with the crosslink sleeve 29 moving downhole while the mandrel 35 remains stationary, then pulling the tool string uphole.

[0038] A bridge plug is used in the examples disclosed herein, however several other tools could be used in this application, such as packers, which may be deployed using a setting tool assembly as disclosed herein.

[0039] Although the invention has been described in terms of embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto. For example, terms such as upper and lower or top and bottom can be substituted with uphole and downhole, respectfully. Top and bottom could be left and right, respectively. Uphole and downhole could be shown in figures as left and right, respectively, or top and bottom, respectively. Generally downhole tools initially enter the borehole in a vertical orientation, but since some boreholes end up horizontal, the orientation of the tool may change. In that case downhole, lower, or bottom is generally a component in the tool string that enters the borehole before a component referred to as uphole, upper, or top, relatively speaking. The first housing and second housing may be top housing and bottom housing, respectfully. Terms like wellbore, borehole, well, bore, oil well, and other alternatives may be used synonymously. Terms like tool string, tool, perforating gun string, gun string, or downhole tools, and other alternatives may be used synonymously. The alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the invention are contemplated which may be made without departing from the spirit of the claimed invention.