Apparatus for launching wiper plugs

Abstract

A tool for launching wiper plugs into a casing string in a gas or oil well during cementing operations employs a collet-like mechanism carrying radially-movable jaws arranged to retain a plug in a fluid flow path when the tool is in a closed position, and to release the plug into the fluid flow path when the tool is in an open position. Selection of the desired operational position of the plug launcher (i.e., open or closed) is effected by actuation of an axially-movable sliding sleeve. Alternative means for actuating the sliding sleeve include rotary actuation about the tool's longitudinal axis, rotary actuation about a radial axis generally normal to the longitudinal axis, rotary actuation about a generally tangent axis, and pneumatic or hydraulic actuation. The tool may be adapted to carry multiple wiper plugs for sequential launching into a casing string.

Claims

1. A plug-launching tool comprising: (a) a generally axisymmetric housing having a housing bore; (b) a sliding sleeve coaxially movable within the housing bore between a closed position and an open position, said sliding sleeve having a cylindrical outer surface sealingly engageable with a cylindrical interval of the housing bore; (c) actuation means, for axially moving the sliding sleeve between a closed position and an open position; (d) a plug receiver bore carried by either the housing or the sliding sleeve, wherein the plug receiver bore: (d.1) is in upstream fluid communication with the housing bore; (d.2) includes a retained plug interval for receiving and releasably retaining a selected plug; and (d.3) is sized to allow passage of the plug downstream of the retained plug interval; (e) a collet assembly coaxially disposed within the housing bore and carried by either the sliding sleeve or the housing, wherein: (e.1) the collet assembly includes a collet body having a generally cylindrical bore configured to accommodate passage of the plug; and (e.2) the collet body carries one or more collet jaws linked to the collet body so as to be movable between a radially-inward closed position and a radially-outward open position, wherein the collet jaws, in their closed position, at least partially occlude the receiver bore, so as to retain the plug within the retained plug interval; and (f) linkage means, for linking axial movement of the sliding sleeve to radial movement of the collet jaws, such that the collet jaws will be urged toward their closed and open positions when the sliding sleeve is moved toward its closed and open positions, respectively.

2. A plug-launching tool as in claim 1 wherein: (a) the sliding sleeve incorporates a piston operatively linked to the sliding sleeve to facilitate movement of the sliding sleeve between its closed and open positions; (b) the housing has one or more piston-actuation openings extending through the wall of the housing; and (c) the piston defines the cylindrical outer surface of the sliding sleeve, with said cylindrical outer surface being sealingly engageable with the cylindrical interval of the housing bore above and below the one or more piston-actuation openings so as to close off the one or more piston-actuation openings.

3. A plug-launching tool as in claim 2 wherein the actuation means actuates the sliding sleeve by rotary actuation about a longitudinal axis of the housing.

4. A plug-launching tool as in claim 3, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein: (a) the rotary drive sleeve allows rotation about the housing axis while reacting against axial translation along the housing; and (b) the rotary drive sleeve threadingly engages a stroking drive sleeve that is close-fitting with and slidably mounted to the housing, while being connected to the piston via the piston-actuation openings so as to prevent rotation about the housing axis, such that it will stroke the sliding sleeve upon rotation of the rotary drive sleeve.

5. A plug-launching tool as in claim 2 wherein the actuation means actuates the sliding sleeve by rotary actuation about a radial axis generally normal to the housing surface.

6. A plug-launching tool as in claim 5, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein the rotary actuation is provided by means of a drive gear rotating on a radially-oriented axle externally mounted to the sliding sleeve, with the drive gear being arranged to mesh with ring gear teeth provided on the rotary drive sleeve.

7. A plug-launching tool as claim 2 wherein the actuation means actuates the sliding sleeve by rotary actuation about a generally tangent axis.

8. A plug-launching tool as in claim 7, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein the rotary actuation is provided by means of a drive gear rotating on a radially-oriented axle externally mounted to the sliding sleeve, with the drive gear being arranged to mesh with ring gear teeth provided on the rotary drive sleeve.

9. A plug-launching tool as in claim 2 wherein the piston is carried by the housing, and wherein the rotary actuation is provided by means of a worm gear tangentially mounted to the housing surface and engaging gear teeth provided on the rotary drive sleeve.

10. A plug-launching tool as in claim 2 wherein actuation of the sliding sleeve is provided by means of a double-acting hydraulic or pneumatic actuator, with the housing being configured to act as a cylinder body, and having external ports for entry of a pressurized actuating fluid, with either rigid or swiveling fluid line connections to the fluid entry ports as appropriate for particular operational requirements.

11. A plug-launching tool as in claim 1 wherein the collet arms bias the collet jaws toward the radially-open position.

12. A plug-launching tool as in claim 11 wherein the collet jaws are biased toward the radially-open position by the collet arms being elastically resilient.

13. A plug-launching tool as in claim 1 wherein the one or more collet jaws are provided with upstream-facing land surfaces collectively providing a land for the plug when the collet jaws are in the closed position.

14. A plug-launching tool comprising: (a) a generally axisymmetric housing having a housing bore; (b) a generally cylindrical receiver cage having a main body with upper and lower ends and defining a plug receiver bore, wherein: (b.1) the receiver cage is coaxially disposed within the housing; (b.2) the housing bore is configured to support the receiver cage at the upper end and/or at the lower end thereof, and defines a housing bore annulus between the housing and the receiver cage's main body; (b.3) the housing bore extends through housing and the receiver cage, and is configured to allow downstream passage of a selected plug; and (b.4) upper and lower sets of receiver cage ports extend through a wall of the receiver cage's main body, defining an unported receiver cage interval between the upper receiver cage ports and the lower receiver cage ports, and defining a retained plug interval in a middle region of the receiver cage's main body, with the length of the retained plug interval being at least approximately equal to the length of the selected plug; (c) a sliding sleeve coaxially and slidably disposed within the housing bore annulus in a region generally corresponding to the upper ports in the receiver cage, wherein the sliding sleeve is movable between: (c.1) a closed position in which the upper receiver cage ports are uncovered so as to allow fluid flow into the housing bore annulus through the upper receiver cage ports; and (c.2) an open position in which the upper receiver cage ports are at least partially blocked so as to restrict fluid flow into the housing bore annulus, such that at least part of the fluid flow will be diverted through the retained plug interval; (d) actuation means, for axially moving the sliding sleeve between a closed position and an open position; (e) a fluid flow path by-passing the retained plug interval, to allow downstream fluid flow within the housing annulus to the lower receiver cage ports; and (f) a collet assembly comprising a plurality of collet jaws linked to the sliding sleeve by collet arms extending axially downward from the sliding sleeve, wherein: (f.1) the collet assembly is configured to axially position each collet jaw in an associated lower receiver cage lower port such that the collet jaws will extend radially inward into the plug receiver bore; (f.2) the collet arms are engageable with the housing bore through a first cam interface to urge the collet jaws toward their closed position when the sliding sleeve is moved toward its closed position; and (f.3) the collet jaws are engageable with the receiver cage through a second cam interface between the jaw segments and surfaces of the receiver cage ports in which they move, so as to urge the collet jaws toward the open position when the sliding sleeve is moved toward its open position.

15. A plug-launching tool as in claim 14 wherein the housing is configured to accommodate one or more auxiliary receiver cages disposed coaxially with the receiver cage recited in claim 2, with each auxiliary receiver cage being provided with an associated auxiliary sliding sleeve, an associated auxiliary collet assembly, and associated auxiliary actuation means.

16. A plug-launching tool as in claim 14 wherein: (a) the tool further comprises a piston operatively linked to the sliding sleeve to facilitate movement of the sliding sleeve between its closed and open positions; and (b) the housing has one or more piston-actuation openings extending through the wall of the housing; wherein the piston is sealingly engageable with the housing bore so as to close off the piston-actuation openings.

17. A plug-launching tool as in claim 16 wherein the actuation means actuates the sliding sleeve by rotary actuation about a longitudinal axis of the housing.

18. A plug-launching tool as in claim 17, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein: (a) the rotary drive sleeve allows rotation about the housing axis while reacting against axial translation along the housing; and (b) the rotary drive sleeve threadingly engages a stroking drive sleeve that is close-fitting with and slidably mounted to the housing, while being connected to the sliding sleeve piston via the piston-actuation openings so as to prevent rotation about the housing axis, such that it will stroke the sliding sleeve upon rotation of the rotary drive sleeve.

19. A plug-launching tool as in claim 16 wherein the actuation means actuates the sliding sleeve by rotary actuation about a radial axis generally normal to the housing surface.

20. A plug-launching tool as in claim 19, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein the rotary actuation is provided by means of a drive gear rotating on a radially-oriented axle externally mounted to the sliding sleeve, with the drive gear being arranged to mesh with ring gear teeth provided on the rotary drive sleeve.

21. A plug-launching tool as claim 16 wherein the actuation means actuates the sliding sleeve by rotary actuation about a generally tangent axis.

22. A plug-launching tool as in claim 21, further comprising a rotary drive sleeve coaxially mounted to and close-fitting with the housing exterior, wherein the rotary actuation is provided by means of a drive gear rotating on a radially-oriented axle externally mounted to the sliding sleeve, with the drive gear being arranged to mesh with ring gear teeth provided on the rotary drive sleeve.

23. A plug-launching tool as in claim 16 wherein the piston is carried by the housing, and wherein the rotary actuation is provided by means of a worm gear tangentially mounted to the housing surface and engaging gear teeth provided on the rotary drive sleeve.

24. A plug-launching tool as in claim 16 wherein actuation of the sliding sleeve is provided by means of a double-acting hydraulic or pneumatic actuator, with the housing being configured to act as a cylinder body, and having external ports for entry of a pressurized actuating fluid, with either rigid or swiveling fluid line connections to the fluid entry ports as appropriate for particular operational requirements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments in accordance with the present disclosure will now be described with reference to the accompanying Figures, in which numerical references denote like parts, and in which:

(2) FIG. 1 is a longitudinal cross-section though one embodiment of a plug-launching tool in accordance with the present disclosure, shown in its retracted position.

(3) FIG. 1A is an enlarged cross-sectional detail view of the plug-launching tool in FIG. 1.

(4) FIG. 2 is a longitudinal cross-section through the plug-launching tool in FIG. 1, shown in its extended position.

(5) FIG. 3 is a side view of an actuation gear mechanism that may be used to move the sliding sleeve from its closed to open positions in the plug-launching tool in FIG. 1.

(6) FIG. 4 is a longitudinal cross-section through an alternative embodiment of a plug-launching tool in accordance with the present disclosure, having a stacked, multiple-wiper plug configuration. The lower stack is shown in the retracted position, and the upper stack is shown in the extended position.

(7) FIG. 5 is a longitudinal cross-section through a further alternative embodiment of a plug-launching tool in accordance with the present disclosure, with pneumatic actuation.

DETAILED DESCRIPTION

Plug-Launching ToolFirst Embodiment

(8) FIGS. 1, 1A, and 2 illustrate a first embodiment 100 of a plug-launching tool in accordance with the present disclosure, comprising: a generally axisymmetric housing assembly; a sliding sleeve assembly; means for axially moving the sliding sleeve; a collet assembly with collet jaws; and a linkage between the collet assembly, the housing assembly, and the sliding sleeve assembly.

(9) In the embodiment shown in FIG. 1 and FIG. 1A, the housing assembly is provided in the form of an elongate and generally axisymmetric housing configured for integration into a cementing head assembly. More specifically, the housing assembly includes: a generally cylindrical outer housing 1110 having upper and lower ends 1111 and 1112, and further having an internal bore 1099 defining a housing ramp 1113, an upper connection thread 1114, a lower connection thread 1115, translation slot through-wall openings 1116 (alternatively referred to herein as piston actuation slots), a seal groove 1117 and a wiper groove 1118, and a spline segment 1119; a generally cylindrical receiver cage 1130 coaxially disposed within internal bore 1099 of outer housing 1110; a generally cylindrical and stepped top cap 1100 having upper and lower ends 1101 and 1102; an external seal groove 1103, an internal seal groove 1104, an internal wiper groove 1105, and top cap splines 1106; and a generally cylindrical stepped bottom cap 1120 having upper and lower ends 1121 and 1122, an external thread 1123, a casing thread 1124 on lower end 1122, a stepped face 1125, and a seal groove 1126.

(10) Receiver cage 1130 comprises a main body 1139 having upper and lower ends 1132 and 1133 and defining a plug receiver bore 1131, with upper and lower sets of cage ports 1134 and 1135 to allow fluid flow through the side wall 1138 of receiver cage 1130. An upper spline pattern 1136 on upper end 1132 of receiver cage 1130 engages a mating spline pattern 1107 on top cap 1100 to react against rotation of cage 1130 relative to housing 1110 and bottom cam face 1137.

(11) The housing assembly is configured to be close-fitting with and to rigidly support cage 1130 at its upper and lower ends 1132 and 1133, including top cap 1100, bottom cap 1120, and outer housing 1110. More specifically, lower end 1133 of cage 1130 is supported by stepped face 1125, with rotational location timing being provided by engagement of cage splines 1136 and top cap splines 1106. Outer housing 1110 has an internal profile defining an annular region 1300 between outer housing 1110 and cage 1130, to thereby allow downstream passage under flow.

(12) Lower end 1102 of top cap 1100 has external threads that are engageable with internal threads on upper end 1111 of housing 1110, for transferring hoist loads from top cap 1100 to housing 1110. Upper end 1101 of top cap 1100 is adapted for securing the assembly (by any suitable means) to components rigged into a top-drive drilling rig.

(13) Seal grooves 1103 and 1104 are provided on the outer and inner diameters, respectively, of top cap 1100 at lower end 1102 thereof. A suitable seal element installed in external seal groove 1103 seals against the upper section of housing 1110 above piston actuation slots 1116 to prevent contaminants from entering annular space 1310 from above. A wiper groove 1105 is provided on the inner diameter of top cap 1100, just above inner seal groove 1104, with a suitable wiper being installed in the groove along the articulating surface between a generally cylindrical piston 1140 and top cap 1100. Seal groove 1117 and wiper grooves 1118 contain suitable seal and wiper elements to prevent the exit of contaminants or fluid from the fluid bore section of tool 100.

(14) Upper end 1121 of the bottom cap 1120 has external threads 1123 that engage internal threads 1115 on lower section 1112 of housing 1110. Upper end 1121 of bottom cap 1120 is configured for mating engagement with lower end 1133 of receiver cage 1130. Lower end 1122 of bottom cap 1120 is threadingly engageable with a casing string. As shown in FIG. 1, a bottom closure ring 1150 having an annular upper section 1151 and an annular lower section 1152 is provided to close off the annular gap between housing 1110 and bottom cap 1120 and to transfer torque from housing 1110 to bottom cap 1120. Seal grooves 1126 are provided in a lower region of the outer surface of bottom cap 1120 for sealing against upper section 1151 of bottom closure ring 1150, to prevent housing contamination from the lower end of tool 100.

(15) The sliding sleeve assembly includes a sliding sleeve 1161 coaxially disposed within an annular region 1300 at an axial position generally corresponding to the position of upper receiver cage ports 1134. In the illustrated embodiment, the sliding sleeve assembly includes a generally cylindrical piston 1140 that is axially movable within a cylindrical interval of the bore of housing 1110, with the length of this cylindrical bore interval being sized to accommodate the axial stroke of piston 1140 and sliding sleeve 1161 of a collet assembly 1160 (described below). Piston 1140 has an upper end 1141, a lower end 1142, and a radially-extending, stepped middle section 1143 with threaded lug holes 1144 and a top lug hole 1145. A seal element installed in inner seal groove 1104 seals against the outer diameter of upper section 1141 of piston 1140.

(16) Sliding sleeve 1161 is configured to interact with upper cage ports 1134 such that when sleeve 1161 is in the closed position (as seen in FIG. 1), cage ports 1134 are open, thus allowing flow into the annulus through upper cage ports 1134 and allowing annular flow downstream to lower receiver ports 1135. This annular flow follows a by-pass flow path around receiver plug interval 1131. When sliding sleeve 1161 is in the open position (as seen in FIG. 2), sleeve 1161 fully or partially blocks upper ports 1134, thereby preventing or restricting fluid flow into the annulus and forcing the fluid to flow through the receiver bore interval.

(17) Collet assembly 1160 in the illustrated embodiment comprises collet jaws 1163 linked to sliding sleeve 1161 by axially-extending arms 1164 that preferably are elastically resilient or otherwise configured to bias collet jaws 1163 toward the radially-open position. In the illustrated embodiment, sliding sleeve 1161 is generally cylindrical and has a top lug hole 1162, with each collet arm 1164 having a collet ramp 1165. This arrangement is configured to axially position jaws 1163 in receiver cage ports 1135, allowing them to extend radially through the receiver cage wall, so as to partially protrude into the receiver bore on the inner diameter of cage 1130, and thus to provide a land for the selected wiper plug 1170 and to retain it in the receiver bore.

(18) Collet ramps 1165 on collet arms 1164 are engageable with the profiled bore of housing 1110 on housing ramp 1113. These surfaces act as a first cam interface forcing collet jaws 1163 into the closed position when sliding sleeve 1161 is moved to its closed position. Cam surface 1137 on cage 1130 and collet jaw bottom ramps 1166 on collet jaws 1163 define a second cam interface as sleeve 1161 is moved to the open position, with collet arms 1164 tending to force jaws 1163 radially outward and thus removing the protrusion into the receiver bore. As such, the land for the selected plug is effectively removed from the receiver bore and no longer provides means for retaining plug 1170.

(19) Sliding sleeve 1161 is provided with axial movement means, for moving sleeve 1161 axially within and relative to housing 1110 for purposes of actuating the plug-launching tool 100 between the closed and open positions. As best seen in FIG. 1A, piston 1140 sealingly engages seal elements in grooves 1117 and 1118 on housing 1110 and seal elements in grooves 1104 and 1105 on top cap 1100, thus providing containment of wellbore fluids. This allows through-wall piston actuation slots 1116 to be placed in this interval, and creates an annular section 1310 between the exterior of housing 1110 and piston 1140. Piston actuation slots 1116 provide access through the wall of housing 1110 to enable direct application of axial force to move or hold piston 1140 in a desired axial position relative to housing 1110.

(20) Piston 1140 may be actuated by a variety of different means, and embodiments in accordance with the present disclosure are not limited or restricted to the use of any particular actuation means, whether disclosed herein or not. By way of non-limiting example, the piston actuation means may comprise a mechanical gear reduction assembly that mounts directly onto the outside of plug-launching tool 100.

(21) FIGS. 1, 1A, and 3 illustrate a gear actuation assembly adapted to convert rotation of a pinion gear 1180 along an axis radially perpendicular to the longitudinal axis of housing 1110 into an axial stroke of sleeve 1161, thereby moving collet jaws 1163 along the collet's two cam interfaces between their closed and open positions. The gear actuation assembly comprises a pinion-type drive gear 1180, a pinion gear lug 1190, a driven ring gear 1200 with profiled teeth 1201 coaxially mounted on the outer radial face of a generally cylindrical rotary drive sleeve 1220, an interfacing ring gear lug 1230 for transferring load from ring gear 1200 to rotary sleeve 1220, a lock key 1240, a lock key lug 1250, and a generally cylindrical anchor lock sleeve 1260 with an internal splined section 1261 and a seal groove 1262.

(22) Rotary drive sleeve 1220 has a seal groove 1221 and an external driving thread 1222 which is close-fitting with and coaxially mounted to the exterior of housing 1110, reacting against lock sleeve 1260 to prevent axial translation. A generally cylindrical stroking drive sleeve 1270 with seal grooves 1271 and 1272, an internal thread 1273, and a lug hole 1274 threadingly engages with rotary drive sleeve 1220 (as described later herein).

(23) Piston 1140 has an upper end 1141, a lower end 1142, and a middle radially-extended stepped section 1143 with threaded lug holes 1144 and a top lug hole 1145. In order to axially move the sliding sleeve 1161, pinion gear 1180 is rotated (such as by a socket wrench or other suitable torque application means), causing the gear teeth of pinion gear 1180 to engage ring gear teeth 1201 to rotate ring gear 1200 about the longitudinal axis of housing 1110, thus rotating rotary drive sleeve 1220 by load transfer through ring gear lugs 1230. This causes stroking drive sleeve 1270 to stroke axially along the exterior of housing 1110 as the rotation of rotary drive sleeve 1220 is converted to axial movement or stroke due to the threaded engagement of rotary drive sleeve 1220 and stroking drive sleeve 1270.

(24) As best seen in FIG. 1A, the illustrated embodiment includes linkage means to facilitate operational engagement between the external stroking components and the internal sliding sleeve assembly, with the linkage means being provided in the form of pins 1280 passing through radial openings 1274 in the wall of stroking drive sleeve 1270, through piston actuation slots 1116 in housing 1110, and into mating lug holes 1144 in piston 1140. Pins 1280 carry circumferential seal grooves 1281 for sealing openings 1274 passing through housing slots 1116 and threading into piston hole 1144.

(25) Piston actuation slots 1116 provide a reaction face against rotation for linkage 1280 and stroking drive sleeve 1270. Accordingly, piston 1140 strokes axially along with stroking drive sleeve 1270 and is further locked with the previously-described sliding sleeve assembly by lugs threaded into holes 1145 and extending into sliding sleeve holes 1162. To avoid premature actuation of this stroking mechanism, lock key 1240 is mounted to the radially exterior face of anchor lock sleeve 1260 and arranged such that it is locked in place between teeth 1201 and secured with lock key lug 1250, thereby preventing rotation of ring gear 1200 and rotary drive sleeve 1220.

(26) Anchor lock sleeve 1260 has an internal splined section 1261 engageable with splines 1106 on top cap 1100 and external splined section 1119 on housing 1110, and thus is capable of transferring torque from top cap 1100 and housing 1110. Anchor lock sleeve 1260 has a lower external face mating onto the upper end of rotary drive sleeve 1220, and stroking drive sleeve 1270 seals against the outer diameter of housing 1110. Circumferential seal grooves 1262, 1221, and 1271 and 1272 are provided in anchor lock sleeve 1260, rotary sleeve 1220, and stroking drive sleeve 1270, respectively.

(27) When plug-launching tool 100 has been fully assembled and rigged into a top-drive-suspended casing string, fluids such as drilling fluid and cement slurry can be pumped through plug-launching tool 100. When tool 100 is in the closed position as shown in FIG. 1, the fluid flow path, in sequence, will be: into tool 100 through internal cylindrical space 1320 through top cap 1100; into upper end 1330 of cage 1130, and down the cage until the flow path is blocked by the loaded wiper plug; out of cage 1130 through upper cage ports 1134 and into annular space 1300 between cage 1130 and housing 1110; downward within annular space 1300 until the flow path is blocked by bottom cap 1120; into cage 1130 through lower cage ports 1135; and downward through bottom cap 1120 and out of tool 100.

(28) After tool 100 has been moved into its open position as shown in FIG. 2, upper ports 1134 are closed off as sliding sleeve 1161 and collet ramps 1165 are stroked axially down housing 1110 along with radially-expanded collet arms 1164. Extended collet jaws 1163 extend radially such that they no longer block the receiver bore, thereby allowing passage of the plug axially downward within cage 1130. With tool 100 now in this configuration, the fluid flow path, in sequence, will be: into tool 100 through cylindrical space 1320 in top cap 1100; into upper end 1330 of cage section 1132 and then downward within the cage until the fluid reaches the top of the wiper plug 1170, pushing the wiper plug down through receiver bore of cage section 1133; and continuing down the receiver bore section until it reaches section 1340 in the bottom cap 1120, at which point the wiper plug exits tool 100.

Plug-Launching ToolStacked Embodiments

(29) There is often a need in cementing operations to launch multiple plugs down the casing string. FIG. 4 illustrates an alternative embodiment 200 of a plug-launching tool in accordance with the present disclosure, with multiple plug stages to facilitate the launching of multiple plugs. In this embodiment, the sliding sleeve assembly, the collet assembly, and the means for releasing individual plugs are generally the same as in previously-described embodiments (i.e., per plug-launching tool 100), but these components are provided in numbers corresponding to the number of plugs to be launched.

(30) Plug-launching tool 200 shown in FIG. 4 includes anchor lock sleeve 1260, external rotating ring 1220, external stroking drive sleeve 1270, interfacing pin 1280, piston 1140, and collet 1160, all generally as in embodiments that carry only one plug. However, the housing assembly is modified to include two independent housing stages (i.e., upper housing component stage 2100 and lower housing stage 2110), which lengthen the assembly to accommodate multiple plugs and activating actuation components inside tool 200. Upper housing stage 2100 retains an upper plug 2130, and lower housing stage 2110 retains a lower plug 2120. In order for these plugs to be launched in the proper sequence, bottom plug 2120 must be launched before top plug 2130.

(31) This stacked embodiment's ability to launch multiple plugs is not limited to two plugs. Theoretically, there is no limit to the number of plugs that can be accommodated by modifying tool 200 to include an additional housing stage for each additional plug, with each housing stage stage having its own set of actuation components (1140, 1160, 1270, 1220, 1260, 1280) and its own receiver cage 1130.

Plug-Launching ToolAdditional Actuation Embodiments

(32) Disclosed embodiments of the plug-launching tool may be readily adapted for pneumatic or hydraulic actuation (or other actuation means) by modifying the disclosed housing and piston assemblies in accordance with technology and methods within the knowledge and capabilities of persons skilled in the art, such that pneumatic or hydraulic components can be used to apply the stroking forces necessary to move the sliding sleeve between the closed and open positions and thus to launch the plug.

(33) By way of non-limiting example, FIG. 5 illustrates a further alternative embodiment 300 of a plug-launching tool in accordance with the present disclosure that uses a pneumatic system for stroking a modified piston 3100 and collet 1160 down a modified housing 3110. Housing 3110 has upper and lower pressure ports 3111 and 3112 extending through the wall of housing 3110 on upper and lower sides of a piston extension 3113, with appropriate pressure fittings mounted in ports 3111 and 3112. Piston 3100 does not have interfacing pin holes as in the embodiment shown in FIG. 1, but has a sealing groove 3114 (with appropriate sealing element) on the terminal circumferential face of piston extension 3113. This seal creates an upper chamber 3120 and a lower chamber 3130 on the upper and lower sides of piston extension 3113. Pressure can be applied into and bled out of chambers 3120 and 3130 through pressure ports 3111 and 3112. The axial stroke of piston 3100 is initiated by pressurizing upper chamber 3120 with compressed air (or other suitable pressurized gas), provided that the force provided to stroke the internal components axially down the housing is sufficiently large to break the friction in the seals in seal grooves 3114, 1104, and 1117. As previously described, the axial stroking of piston 3100 and collet 1160 will cause the plug to be released from plug-launching tool 300. Pressure may then be bled from upper chamber 3120, followed by pressurization of lower chamber 3130 through pressure port 3112, thus generating the axial force necessary to stroke piston 3100 back up housing 3110, and thereby returning tool 300 to its closed position.

(34) It will be readily appreciated by those skilled in the art that various modifications to embodiments in accordance with the present disclosure may be devised without departing from the scope of the present teachings, including modifications which may use equivalent structures or materials hereafter conceived or developed. It is to be especially understood that the scope of the present disclosure is not intended to be limited to described or illustrated embodiments, and that the substitution of a variant of a claimed or illustrated element or feature, without any substantial resultant change in functionality, will not constitute a departure from the scope of the disclosure.

(35) In this patent document, any form of the word comprise is to be understood in its non-limiting sense to mean that any item following such word is included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article a does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element. Any use of any form of the terms connect, engage, couple, attach, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure.

(36) Relational and conformational terms such as perpendicular, coaxial, and cylindrical are not intended to denote or require absolute mathematical or geometrical precision. Accordingly, such terms are to be understood as denoting or requiring substantial precision only (e.g., substantially perpendicular) unless the context clearly requires otherwise. Wherever used in this document, the terms typical and typically are to be interpreted in the sense of representative of common usage or practice, and are not to be understood as implying essentiality or invariability.