U.S. patent application number 13/337985 was filed with the patent office on 2013-06-27 for modular dart launcher with status indicator.
This patent application is currently assigned to VETCO GRAY INC.. The applicant listed for this patent is Shripad Hedge, Dinesh Narayan, Chad Eric Yates. Invention is credited to Shripad Hedge, Dinesh Narayan, Chad Eric Yates.
Application Number | 20130161005 13/337985 |
Document ID | / |
Family ID | 48653423 |
Filed Date | 2013-06-27 |
United States Patent
Application |
20130161005 |
Kind Code |
A1 |
Yates; Chad Eric ; et
al. |
June 27, 2013 |
MODULAR DART LAUNCHER WITH STATUS INDICATOR
Abstract
A dart launcher launches a dart by placing the dart within a
launcher bore formed within a launcher body. The launcher body also
defines a central bore coupled inline with a tubing string and in
fluid communication with the launcher bore. The launcher bore is
formed at an angle to the central bore. A release assembly is
coupled to the launcher body and includes a release rod protruding
into the launcher bore to selectively release the dart. A visual
indicator assembly is coupled to the launcher body downstream from
the release assembly and includes a flapper protruding into the
launcher bore. The release assembly is actuated by the dart
rotating the flapper to rotate an arm from a non-released position
to a released position.
Inventors: |
Yates; Chad Eric; (Houston,
TX) ; Hedge; Shripad; (Bangalore, IN) ;
Narayan; Dinesh; (Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yates; Chad Eric
Hedge; Shripad
Narayan; Dinesh |
Houston
Bangalore
Bangalore |
TX |
US
IN
IN |
|
|
Assignee: |
VETCO GRAY INC.
Houston
TX
|
Family ID: |
48653423 |
Appl. No.: |
13/337985 |
Filed: |
December 27, 2011 |
Current U.S.
Class: |
166/284 ;
166/75.15 |
Current CPC
Class: |
E21B 23/10 20130101;
E21B 33/05 20130101 |
Class at
Publication: |
166/284 ;
166/75.15 |
International
Class: |
E21B 33/13 20060101
E21B033/13 |
Claims
1. A wellbore drop member launcher comprising: a launcher body
defining a central bore having a central bore axis, the launcher
body having a lower end configured to attach to a string of pipe
extending into a wellbore; the launcher body defining a launcher
bore having a launcher bore axis at an angle to the central bore
axis, the launcher bore in fluid communication with the central
bore; a release assembly coupled to the launcher body and having a
release rod protruding into the launcher bore to prevent movement
of a drop member positioned within the launcher bore in a drop
member hold position; wherein the release assembly is configured to
move the release rod to a drop member release position to
selectively release the drop member positioned within the launcher
bore; and a visual indicator assembly coupled to the launcher body
and configured to provide a mechanically produced visual indication
that the drop member has moved from the launcher bore to the
central bore.
2. The wellbore drop member launcher of claim 1, wherein the
release assembly comprises: a piston assembly coupled to the
release rod and configured to move the release rod between the drop
member hold position and the drop member release position; and
wherein the piston assembly biases the release rod to the drop
member hold position.
3. The wellbore drop member launcher of claim 2, further
comprising: a release body housing interposed between the piston
assembly and the launcher body, the release rod at least partially
disposed within the release body housing when in the drop member
hold position and a portion of the piston assembly coupling to the
release rod within the release body housing; a window having a
length formed in a portion of a release body housing; an indicator
screw threaded into the portion of the piston assembly so that an
end of the screw is visible through the window; and wherein the
indicator screw moves from a first end of the window to a second
end of the window when the piston assembly operates to move the
release rod between the drop member hold and the drop member
release positions, providing a visual indication of release
assembly actuation.
4. The wellbore drop member launcher of claim 3, wherein: the
release rod defines a pressure passage extending from an end of the
release rod disposed within the launcher bore through a center of
the release rod to an annular chamber within the release body
housing; and wherein the pressure passage is configured to equalize
pressure between the release body housing and the launcher bore to
prevent premature dart member release.
5. The wellbore drop member launcher of claim 2, wherein the piston
assembly is a hydraulically actuated piston assembly.
6. The wellbore drop member launcher of claim 2, wherein the piston
assembly is a pneumatically actuated piston assembly.
7. The wellbore drop member launcher of claim 1, wherein the visual
indicator assembly comprises: an indicator bore defined by the
launcher body extending from an exterior of the launcher body to
the launcher bore; an indicator housing coupled to the launcher
body proximate to the indicator bore; an indicator rod extending
through the indicator housing into the indicator bore; a flapper on
an end portion of the indicator rod; wherein the flapper is
perpendicular to the indicator rod and extends from the indicator
bore into the launcher bore; an arm secured to an end of the
indicator rod that protrudes from the indicator housing and located
so as to be visible to an operator; wherein the arm extends from
the indicator rod perpendicular to the indicator rod and parallel
to the flapper; and wherein as the drop member passes the flapper
it rotates the flapper, indicator rod, and arm to indicate release
of the drop member.
8. The wellbore drop member launcher of claim 7, further
comprising: a pre-release detent formed in a surface of the
indicator rod; a post-release detent formed in a surface of the
indicator rod axially aligned with the pre-release detent and
circumferentially spaced from the pre-release detent; and a spring
plunger disposed within the indicator housing and adapted to insert
into the pre-release detent to limit rotation of the indicator rod
prior to passage of the drop member; and the spring plunger further
adapted to release from the pre-release detent to allow rotation of
the indicator, rod as the drop member passes and insert into the
post-release detent to prevent further rotation of the indicator
rod following passage of the drop member.
9. The wellbore drop member launcher of claim 7, wherein the
flapper, indicator rod, and arm rotate ninety degrees.
10. A wellbore drop member launcher comprising: a launcher body
defining a central bore having a central bore axis, the launcher
body having a lower end configured to attach to a tubing string
extending into a wellbore; the launcher body defining a launcher
bore having a launcher bore axis at an angle to the central bore
axis, the launcher bore in fluid communication with the central
bore; a release assembly coupled to the launcher body and having a
release rod protruding into the launcher bore to prevent movement
of a drop member positioned within the launcher bore into the
tubing string; wherein the release assembly is configured to move
the release rod with a piston assembly from a drop member hold
position to a drop member release position to selectively release
the drop member; wherein the piston assembly biases the release rod
to the drop member hold position; a pressure passage defined by the
release rod and configured to equalize pressure between a
compressible portion of the piston assembly and the launcher body
to prevent premature drop member release, the pressure passage
extending from an end of the release rod disposed within the
launcher bore through a center of the release rod to an annular
chamber within the piston assembly; an indicator housing coupled to
the launcher body proximate to an indicator bore defined by the
launcher body and extending from an exterior of the launcher body
to the launcher bore; an indicator rod extending through the
indicator housing into the indicator bore, the indicator rod having
a flapper on an end portion of the indicator rod and an arm secured
to an opposite end of the indicator rod; wherein the flapper and
the arm are perpendicular to the indicator rod and parallel to each
other; wherein the flapper extends from the indicator bore into the
launcher bore and the arm is located so as to be visible to an
operator; wherein as the drop member passes the flapper it will
rotate the flapper, indicator rod, and arm to indicate release of
the drop member.
11. The wellbore drop member launcher of claim 10, further
comprising: a release body housing coupling the piston assembly to
the launcher bore, the release rod partially disposed within the
release body housing; a window having a length formed in a portion
of a release body housing; an indicator screw threaded into a
portion of the piston assembly so that an end of the screw is
visible through the window; and wherein the indicator screw moves
from a first end of the window to a second end of the window when
the piston assembly operates to move the release rod, providing a
visual indication of release assembly actuation.
12. The wellbore drop member launcher of claim 10, wherein the
piston assembly is a hydraulically actuated piston assembly.
13. The wellbore drop member launcher of claim 10, wherein the
piston assembly is a pneumatically actuated piston assembly.
14. The wellbore drop member launcher of claim 10, further
comprising: a pre-release detent formed in a surface of the
indicator rod; a post-release detent formed in a surface of the
indicator rod axially aligned with the pre-release detent and
circumferentially spaced from the pre-release detent; and a spring
plunger disposed within the indicator housing and adapted to insert
into the pre-release detent to limit rotation of the indicator rod
prior to passage of the drop member; and the spring plunger further
adapted to release from the pre-release detent to allow rotation of
the indicator rod as the drop member passes and insert into the
post release detent to prevent further rotation of the indicator
rod following passage of the drop member.
15. The wellbore drop member launcher of claim 10, wherein the
flapper, indicator rod, and arm rotate ninety degrees.
16. A method for launching a drop member into a wellbore tubing
string, comprising: (a) providing a launcher body having a central
bore with a central bore axis and a launcher bore with a launcher
bore axis at an angle to the central bore axis and in fluid
communication with the central bore; (b) placing a drop member in
the launcher bore and resting the drop member on a release rod of a
release assembly coupled to the launcher body; (c) coupling a
visual indicator assembly to the launcher body so that the visual
indicator assembly is in communication with the launcher bore at a
location downstream from the release assembly; (d) coupling the
launcher body in line with the tubing string so that the central
bore of the launcher body aligns with a body passage through the
tubing string; (e) actuating the release assembly to allow the drop
member to move from the launcher body into the central bore where
the drop member may move down the tubing string; and (f) actuating
the visual indicator assembly with the drop member as the drop
member moves from the launcher bore into the central bore.
17. The method of claim 16, wherein step (e) comprises applying
hydraulic pressure to a piston assembly of the release assembly to
move the release rod from the launcher bore.
18. The method of claim 16, wherein step (e) comprises applying
pneumatic pressure to a piston assembly of the release assembly to
move the release rod from the launcher bore.
19. The method of claim 16, wherein step (f) comprises: moving a
flapper of the visual indicator assembly with the drop member to
rotate an indicator rod and an arm coupled to the indicator rod;
and signaling to an operator that the drop member has moved into
the central bore with rotation of the arm.
20. The method of claim 19, wherein further comprising: securing a
spring plunger within a housing of the visual indicator assembly
adapted to insert into a pair of circumferentially spaced detents;
and limiting rotation of the indicator rod by inserting a plunger
of the spring plunger into the detents.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates in general to drop balls, plugs, or
darts used to operate well tool functions and, in particular, to a
drop ball, plug, or dart launcher with a status indicator.
[0003] 2. Brief Description of Related Art
[0004] Standard dart or ball launchers have a member that defines a
central bore that may be coupled inline with a drill or tubing
string. The launchers also include an angular bore that intersects
the central bore at a shallow angle between the angular bore and
the central bore. A dart or ball is dropped into the angular bore,
and after opening a series of valves, the ball or dart is
introduced into the central bore for further movement of the dart
or ball down the borehole. There, the dart or ball will land at a
predetermined location to block the borehole and allow hydraulic
tool operations. In order to minimize the potential that the ball
will snag or hang up as it moves from the angular bore to the
central bore, the angle of the intersection between the two axes is
as close to zero degrees as possible. This necessitates that the
launcher must be very tall to smooth out the transition between the
angular bore and the central bore. The height can make the launcher
very difficult to access and operate.
[0005] Other devices couple inline with the drill or tubing string
and use a series of valves to launch the ball or dart. The dart or
ball may become stuck or snagged at the valve openings, preventing
successful release of the dart or drop ball. In addition, these
types of devices require bypass passages within the valves so that
fluids may flow around the darts and valves prior to launching the
dart or ball. These passages restrict fluid flow through the
running string and may become clogged. Clogging of these passages
will, in turn, require stoppage of drilling operations in order to
remove and reset the launcher for operation. Even when not blocked,
these passages may restrict the flow of fluid downhole, causing
further complications in drilling operations.
[0006] Still other devices may couple inline with the drill or
tubing string and use a series of balls to launch darts or plugs
contained within the device. These devices rely on complex landing
and sliding sleeve devices, to bypass the fluids around the landed
balls and darts, again restricting fluid flow through the string.
These devices also do not provide an indication that the proper
dart or plug has been launched following landing of the ball.
[0007] Generally, following launch of a ball, dart, or plug,
operators wait for an increase in pressure within the tubing string
to indicate that the ball, dart, or plug has properly released into
the drill string and landed at the ball, dart, or plug seat.
Operators may then proceed with operations such as cementing or
running tool actuation. However, in some wells, particularly in
deep subsea wells, the distances between the operating platform and
the landing location are large enough that it may take over an hour
for the dart to land at the seat. As a result, operators may
proceed with operations following release of the ball, dart, or
plug but before they have received any indication that the ball,
dart, or plug has landed. In the event that the ball, dart, or plug
becomes hung up or snagged in the launcher and does not release
into the tubing string, the well may be significantly damaged,
necessitating expensive and time consuming repair operations. Some
launchers include an electrical system for indicating that the
dart, ball, or plug has released, however these systems require
complex components that are prone to failure and difficult to adapt
to changing types and sizes of balls, darts, and plugs. Thus, there
is a need for a launcher that launches the dart or ball from an
inline coupling without restricting fluid flow through the central
bore of the tubing and that may provide an indication of a
successful launch of the ball, dart, or plug.
SUMMARY OF THE INVENTION
[0008] These and other problems are generally solved or
circumvented, and technical advantages are generally achieved, by
preferred embodiments of the present invention that provide a
modular dart launcher with a status indicator and a method for
using the same.
[0009] In accordance with an embodiment of the present invention, a
wellbore drop member launcher is disclosed. The launcher includes a
launcher body defining a central bore having a central bore axis,
the launcher body having a lower end configured to attach to a
string of pipe extending into a wellbore. The launcher body also
defines a launcher bore having a launcher bore axis at an angle to
the central bore axis, the launcher bore in fluid communication
with the central bore. A release assembly is coupled to the
launcher body and has a release rod protruding into the launcher
bore to prevent movement of a drop member positioned within the
launcher bore in a drop member hold position. The release assembly
is configured to move the release rod to a drop member release
position to selectively release the drop member positioned within
the launcher bore. A visual indicator assembly is, coupled to the
launcher body and is configured to provide a mechanically produced
visual indication that the drop member has moved from the launcher
bore to the central bore.
[0010] In accordance with another embodiment of the present
invention, a wellbore drop member launcher is disclosed. The
launcher includes a launcher body defining a central bore having a
central bore axis, the launcher body having a lower end configured
to attach to a tubing string extending into a wellbore. The
launcher body also defines a launcher bore having a launcher bore
axis at an angle to the central bore axis. The launcher bore is in
fluid communication with the central bore. A release assembly is
coupled to the launcher body and has a release rod protruding into
the launcher bore to prevent movement of a drop member positioned
within the launcher bore into the tubing string. The release
assembly is configured to move the release rod with a piston
assembly from a drop member hold position to a drop member release
position to selectively release the drop member. The piston
assembly also biases the release rod to the drop member hold
position. A pressure passage is defined by the release rod and is
configured to equalize pressure between a compressible portion of
the piston assembly and the launcher body, preventing premature
drop member release. The pressure passage extends from an end of
the release rod disposed within the launcher bore through a center
of the release rod to an annular chamber within the piston
assembly. An indicator housing is coupled to the launcher body
proximate to an indicator bore that is defined by the launcher body
and extends from an exterior of the launcher body to the launcher
bore. An indicator rod extends through the indicator housing into
the indicator bore. The indicator rod has a flapper formed near an
end of the indicator rod and an arm secured to an opposite end of
the indicator rod. The flapper and the arm are perpendicular to the
indicator rod and parallel to each other. The flapper extends from
the indicator bore into the launcher bore and the arm is visible to
an operator. As the drop member passes the flapper it will rotate
the flapper, indicator rod, and arm to indicate release of the drop
member.
[0011] In accordance with yet another embodiment of the present
invention, a method for launching a drop member into a wellbore
tubing string is disclosed. The method provides a launcher body
having a central bore with a central bore axis and a launcher bore
with a launcher bore axis at an angle to the central bore axis and
in fluid communication with the central bore. The method places a
drop member in the launcher bore and resting the drop member on a
release rod of a release assembly coupled to the launcher body. The
method couples a visual indicator assembly to the launcher body so
that the visual indicator assembly is in communication with the
launcher bore at a location downstream from the release assembly.
The method couples the launcher body in line with the tubing string
so that the central bore of the launcher body aligns with a body
passage through the tubing string. The method then actuates the
release assembly to allow the drop member to flow from the launcher
body into the central bore where the drop member may move down the
tubing string. The method actuates the visual indicator assembly
with the drop member as the drop member moves from the launcher
bore into the central bore.
[0012] An advantage of a preferred embodiment is that it provides a
dart launcher that may be used in high fluid pressures situations.
In addition, the disclosed embodiments provide an apparatus and
method to easily launch a ball, dart, or plug with minimal human
intervention. Still further, the disclosed embodiments provide a
modular apparatus that allows for variation in the size of the
ball, dart, or plug launched. Sill further, the disclosed
embodiment provides a visual indicator for an operator to confirm
the successful launch of the ball, dart, or plug that does not rely
on complicated electronics systems that may be prone to failure in
harsh operating environments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] So that the manner in which the features, advantages and
objects of the invention, as well as others which will become
apparent, are attained, and can be understood in more detail, more
particular description of the invention briefly summarized above
may be had by reference to the embodiments thereof which are
illustrated in the appended drawings that form a part of this
specification. It is to be noted, however, that the drawings
illustrate only a preferred embodiment of the invention and are
therefore not to be considered limiting of its scope as the
invention may admit to other equally effective embodiments.
[0014] FIG. 1 is a perspective view of a dart launcher in
accordance with an embodiment of the present invention.
[0015] FIG. 2 is a sectional view of the dart launcher taken along
ling 2-2 of FIG. 1.
[0016] FIG. 3 is a sectional view of a release assembly of the dart
launcher taken along line 3-3 of FIG. 1.
[0017] FIG. 4 is an enlarged view of a portion of the dart launcher
indicated at FIG. 2.
[0018] FIG. 4A is an enlarged view of a surface of the release
assembly taken along line 4A of FIG. 3.
[0019] FIG. 5 is an enlarged view of the portion of the dart
launcher indicated at FIG. 2 following release of a dart.
[0020] FIG. 5A is an enlarged view of the surface of the release
assembly taken along line 5A of FIG. 5.
[0021] FIG. 6 is a perspective view of a visual indicator assembly
of the dart launcher.
[0022] FIG. 6A is a front view of the visual indicator assembly of
FIG. 6.
[0023] FIG. 7 is a sectional view of the visual indicator assembly
taken along line 7-7 of FIG. 2.
[0024] FIG. 8 is a sectional view of a portion of a spring plunger
of the visual indicator assembly in pre-release position taken
along line 8-8 of FIG. 6.
[0025] FIG. 9 is a perspective view of the visual indicator
assembly following release of the dart.
[0026] FIG. 9A is a front view of the visual indicator assembly of
FIG. 9.
[0027] FIG. 9B is a sectional view of a portion of a spring plunger
of the visual indicator assembly in a post-release position taken
along line 9B-9B of FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings which
illustrate embodiments of the invention. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the illustrated embodiments set forth
herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art. Like numbers
refer to like elements throughout, and the prime notation, if used,
indicates similar elements in alternative embodiments or
positions.
[0029] In the following discussion, numerous specific details are
set forth to provide a thorough understanding of the present
invention. However, it will be obvious to those skilled in the art
that the present invention may be practiced without such specific
details. Additionally, for the most part, details concerning
drilling rig operation, well tool manufacture, well tool operation,
well tool uses, and the like have been omitted inasmuch as such
details are not considered necessary to obtain a complete
understanding of the present invention, and are considered to be
within the skills of persons skilled in the relevant art.
[0030] Referring to FIG. 1, a dart launcher 11 is shown. Dart
launcher 11 includes an upper tubular member or top pup 13 adapted
to connect to a tubular member of a tubing or drill string. Fluid,
such as drilling fluid, may circulate through dart launcher 11 from
an external source coupled to top pup 13. Dart launcher 11 also
includes a lower tubular member or bottom pup 15 adapted to connect
to a tubular member of a tubing or drill string. The tubing string
may continue into a well to transport the fluid to a. subsurface
location. A person skilled in the art will recognize that top pup
13 and bottom pup 15 have ends adapted to connect dart launcher 11
in line in a tubing string. In the illustrated embodiment, the ends
of top pup 13 and bottom pup 15 comprise threaded connectors. In
other exemplary embodiments, the ends of top pup 13 and bottom pup
15 may be any suitable connector type such that dart launcher 11
may couple inline to a tubing string.
[0031] Dart launcher 11 also includes a launcher body 17, a dart
release assembly 19, and a visual indicator assembly 21. Top pup 13
and bottom pup 15 may secure to or couple to launcher body 17 on
opposite ends of launcher body 17 so that top pup 13 and bottom pup
15 are coaxial with an axis 23 of a central bore 25 of launcher
body 17 (FIG. 2). In an exemplary embodiment, top pup 13 and bottom
pup 15 secure to launcher body 17 through threaded connections. A
person skilled in the art will understand that other connection
types may be used.
[0032] Referring to FIG. 2, a sectional view of launcher body 17 is
shown. Launcher body 17 defines central bore 25 and a launcher bore
27 that intersects central bore 25, allowing for fluid
communication between central bore 25 and launcher bore 27.
Launcher bore 27 intersects central bore 25 at opening 35. Opening
35 will be of a size and shape to allow a ball, plug, or dart 33 to
pass from launcher bore 27 into central bore 25. Launcher bore 27
has an axis 29. Axis 29 my intersect axis 23 at an angle 31. Angle
31 may comprise any suitable angle such that a drop member or dart
33 may pass from launcher bore 27 into central bore 25 for travel
through a coupled tubing string. In the illustrated embodiment,
central bore 25 and launcher bore 27 are formed from a single
launcher body 17. In other exemplary embodiments, central bore 25
and launcher bore 27 may be defined by separate bodies coupled or
secured together. Dart release assembly 19 couples to launcher body
17 proximate to launcher bore 27 such that dart release assembly 19
may selectively allow passage of dart 33 from launcher bore 27 into
central bore 25 through opening 35. Visual indicator assembly 21
will couple or secure to launcher body 17 proximate to opening 35
such that as dart 33 passes from launcher bore 27 into central bore
25, described in more detail below, visual indicator assembly 21
will indicate such passage. For illustrative purposes, visual
indicator assembly 21 has been shown in the sectional view of FIG.
2 to aid in the illustration of the relationship between visual
indicator assembly 21 and dart release assembly 19.
[0033] Referring to FIG. 3, a side sectional view of dart release
assembly 19 is shown. Dart release assembly 19 includes a release
housing 37 and a pressure chamber 39. Pressure chamber 39 may be a
hydraulic pressure chamber, pneumatic pressure chamber, or the
like. Pressure chamber 39 is coupled to an end of release housing
37 by any suitable means. In an exemplary embodiment, pressure
chamber 39 is bolted to release housing 37. Pressure chamber 39
includes a piston 41 extending from an interior of pressure chamber
39 into an actuator bore 43 of release housing 37. Piston 41 has a
piston head 45 that seals to the interior surfaces of pressure
chamber 39 to divide pressure chamber 39 into two sections. Each
section of pressure chamber 39 is in communication with a pressure
source through ports 47, 49. The pressure source may be a hydraulic
pressure source that supplies hydraulic pressure through ports 47,
49. In other embodiments, the pressure source may be a pneumatic
pressure source that supplies pneumatic pressure through ports 47,
49. In the exemplary embodiment, port 47 comprises a dart release
port, and port 49 comprises a vent. Pressure may be supplied to
port 47 to assert a force on piston head 45 to move piston 41 from
a dart hold position, where dart 33 (FIG. 2) is prevented from
moving into central bore 25, to a dart release position, where dart
33 (FIG. 5) is allowed to move into central bore 25. Pressure
within pressure chamber 39 will vent through port 49 when pressure
is supplied through port 47 to move piston 41 from the dart hold to
the dart release position. In other embodiments, pressure may be
supplied to port 49 to assert a force on piston head 45 to move
piston 41 from the dart release position to the dart hold position,
shown in FIG. 3.
[0034] A shaft of piston 41 passes through a spring 51 disposed
within actuator bore 43. An end of the shaft of piston 41 will
couple to a spring perch 53 disposed within actuator bore 43
opposite pressure chamber 39 in the dart hold position. Spring
perch 53 may move through actuator bore 43 with piston 41 in
response to application of pressure to pressure chamber 39. Spring
51 will be positioned to bias spring perch 51 to the dart hold
position of FIG. 3. Actuator bore 43 will include an indicator
window 55 extending a portion of a length of actuator bore 43. An
indicator screw 57 will pass through indicator window 55 and couple
to spring perch 53 such that a head of indicator screw 57 will
remain disposed within indicator window 55. As spring perch 53
moves through actuator bore 43 indicator screw 57 will move from an
end of window 55 to an opposite end of window 55. In an exemplary
embodiment, indicator screw moves from an area spaced from pressure
chamber 39 to an area proximate to pressure chamber 39.
[0035] Release housing 37 defines actuator bore 43 and a rod bore
59. Rod bore 59 and actuator bore 43 are separated by a chamber
wall 61 having a port for communication between actuator bore 43
and rod bore 59. Spring perch 53 may include a protrusion extending
into the port of chamber wall 61 such that a release rod 63 may
couple to spring perch 53. As shown in FIG. 4, a seal 60 may be
positioned within chamber wall 61 to seal to release rod 63.
Referring to FIG. 3, a surface of spring perch 53 may contact
chamber wall 61 in the dart hold position, limiting movement of
spring perch 53 away from pressure chamber 39. Release rod 63
extends from rod bore 59 to an exterior of release housing 37.
Release rod 63 couples to spring perch 53 such that as spring perch
53 moves with piston 61, release rod 63 will move in response.
Release rod 63 includes a flange portion 65 that seals with a seal
66 (FIG. 4) to rod bore 59. Flange portion 65 may be spaced from an
end of release rod 63 coupled to spring perch 53 to define an
annular passage 69 between flange portion 65 and chamber wall 61 in
the dart hold position of FIGS. 3 and 4. Release rod 63 will
include a pressure passage 67 extending through a length of release
rod 63 and in fluid communication with annular passage 69. Launcher
bore 27 will be in fluid communication with annular passage 69
through pressure passage 67 such that a hydraulic pressure of
launcher bore 27 will be substantially equivalent to the hydraulic
pressure within annular passage 69. Release housing 37 further
includes a flange 71 formed on an end of release housing 37
opposite pressure chamber 39. Flange 71 provides a mating contact
to couple dart release assembly 19 to launcher body 17. In the
illustrated embodiment, flange 71 is bolted to launcher body
17.
[0036] Referring to FIG. 4, dart release assembly 19 is shown
coupled to launcher body 17 and in the dart hold position of FIG.
3. As shown, an end of release rod 63 will extend from an end of
releasing housing 37 and pass through a release rod bore 73 formed
in a wall of launcher body 17. Release rod 63 will seal to release
rod bore 73 with a seal 74 positioned within release rod bore 73.
Release rod 63 will extend a sufficient distance into launcher bore
27 to prevent passage of dart 33 from launcher bore 27 into central
bore 25. A person skilled in the art will recognize that release
rod 63 extends into launcher bore 27 a sufficient length to allow
for variation in the size of dart 33. Thus, dart launcher 11 may be
used in various types of operations to release or launch multiple
types of darts 33.
[0037] As shown in FIG. 4A, indicator screw 57 will be positioned
in an end of window 55 proximate to launcher body 17. Referring to
FIG. 5, pressure has been supplied to port 47, causing piston 41 to
move to the dart release position. In response, spring perch 53 has
moved toward pressure chamber 39, compressing spring 51. Release
rod 63 will be pulled into rod bore 59 until flange portion 65
contacts chamber wall 61 opposite actuator bore 43. This will pull
release rod 63 completely from launcher bore 27, allowing dart 33
to move freely from launcher bore 27 into central bore 25 for
further movement through a tubing string coupled to bottom pup 15
(FIG. 1). As shown in FIG. 5A, when spring perch 53 moves from the
dart hold position to the dart release position, indicator screw 57
will move through indicator window 55 from a position proximate to
launcher body 17 (FIG. 4A) to a position proximate to pressure
chamber 39 (FIG. 5A).
[0038] Referring to FIG. 6, visual indicator assembly 21 is shown.
Visual indicator assembly 21 includes an indicator housing 75, and
an indicator rod 77. Indicator rod 77 has an interior end 76 and an
exterior end 78. Indicator rod 77 will pass through an indicator
housing bore 79 (FIG. 7) extending through indicator housing 75.
Indicator housing 75 will define a flange 81 adapted to secure
visual indicator assembly 21 to launcher body 17. In the
illustrated embodiment, flange 81 defines a plurality of bores
through which a plurality of bolts are passed to thread into
corresponding threaded bores of launcher body 17. A flapper 83 is
formed near interior end 76 of indicator rod 77. Flapper 83 will be
orthogonal to indicator rod 77. Indicator rod 77 will have a length
greater than a length of indicator housing 75 such that, when
indicator rod 77 is passed through indicator housing 75, interior
end 76 having flapper 83 will protrude from indicator housing 75
into launcher body 17 as shown in FIG. 7. Exterior end 78 of
indicator rod 77 will protrude from an opposite side of indicator
housing 75. An arm 85 will be secured to indicator rod 77 on
exterior end 78. In the illustrated embodiment, arm 85 is
orthogonal to indicator rod 77 and extends from indicator rod 77
parallel to flapper 83.
[0039] Referring to FIG. 7, indicator rod 77 also includes an
indicator flange 87 formed between interior end 76 and exterior end
78. Indicator flange 87 will define an outward facing shoulder 89
adapted to contact an inwardly facing shoulder 91 formed on an
interior end of indicator housing 75. Contact between outward
facing shoulder 89 and inwardly facing shoulder 91 will limit
movement of indicator rod 77 in an outward direction. A seal 90
will be positioned in indicator housing bore 79 to seal indicator
rod 77 to indicator housing bore 79 between outward facing shoulder
89 of indicator flange 87 and exterior end 78 of indicator rod
77.
[0040] Indicator housing 75 will secure to launcher body 17 so that
indicator rod 77 will extend into an indicator bore 93. A seal 94
will be positioned within indicator housing 75 to seal an outer
diameter of indicator housing 75 to indicator bore 93. Indicator
bore 93 extends from an exterior surface of launcher body 17 to
launcher bore 27. A keyhole 95 may be formed in an interior end of
indicator bore 93. Interior end 76 of indicator rod 77 inserts into
keyhole 95 so that indicator rod 77 may rotate on an axis 97.
Flapper 83 will be spaced along axis 97 from interior end 76 so
that interior end 76 may fully seat within keyhole 95. When
indicator rod 77 is positioned within indicator bore 93 and seated
within keyhole 95, flapper 83 will extend into launcher bore 27. In
the illustrated embodiment, flapper 83 will extend from indicator
rod 77 such that axis 29 of launcher bore 27 may pass through an
outer end of flapper 83. In other embodiments, the outer end of
flapper 83 may be proximate to axis 29 of launcher bore 27, but
axis 29 may not pass through the outer end of flapper 83.
[0041] As shown in FIG. 6, visual indicator assembly 21 also
includes a spring plunger 99 positioned within a spring plunger
bore 101 formed in indicator housing 75. Referring to FIG. 8,
spring plunger bore 101 extends from an exterior of indicator
housing 75 to indicator housing bore 79. Spring plunger 99 will be
disposed within spring plunger bore 101. Spring plunger 99 includes
a plunger housing 103, a plunger 105, and a spring member 107.
Plunger housing 103 secures within spring plunger bore 101 against
a downward facing shoulder 109. Plunger housing 103 has an open end
proximate to indicator housing bore 79 into which plunger 105
inserts. Spring member 107 will be disposed between an internal
shoulder 111 of indicator housing 103 and an end 113 of plunger 105
proximate to an exterior of indicator housing 75. Plunger 105
includes an end 115 opposite end 113 and proximate to indicator
housing bore 79. Plunger 105 includes a flange 117 between end 113
and exterior end 115. Flange 117 defines a shoulder 119 facing
indicator housing bore 79. Exterior end 115 protrudes from flange
117 toward indicator housing bore 79. During operation of visual
indicator assembly 21, spring member 107 will bias plunger 105 to
the position illustrated in FIG. 8, where shoulder 119 will contact
an oppositely facing shoulder 121 to limit movement of plunger 105.
As shown, exterior end 115 may seat within a pre-launch detent 123
formed on an exterior surface of indicator rod 77. When exterior
end 115 seats within pre-launch detent 123 rotation of indicator
rod 77 will be stopped. When not in the position shown in FIG. 8,
exterior end 115 may be in contact with an exterior surface of
indicator rod 77, but shoulder 119 will be spaced from oppositely
facing shoulder 121, allowing for exterior end 115 to move into
pre-launch detent 123 when indicator rod 77 is rotated.
[0042] As shown in FIG. 9B, indicator rod 77 includes a post-launch
detent 123'. Pre-launch detent 123 will be circumferentially spaced
from post-launch detent 123'. When flapper 83 extends into launcher
bore 27 as shown in FIGS. 2, 6, and 7, exterior end 115 of plunger
105 will extend into pre-launch detent 123 as shown in FIG. 8. In
this manner, spring plunger 99 will prevent rotation of indicator
rod 77 prior to launch of dart 33 so that visual indicator assembly
21 will not incorrectly indicate a launch of dart 33. When dart 33
is launched, dart 33 will overcome the spring force of spring
member 107, allowing for rotation of indicator rod 77 and moving
flapper 83 to the position of FIG. 9. Exterior end 115 of plunger
105 will then extend into post-launch detent 123' (FIG. 9B), which
is circumferentially spaced from pre-launch detent 123, to prevent
additional rotation of indicator rod 77.
[0043] During operation of dart launcher 11, dart release assembly
19 will be in the position shown in FIGS. 2, 3, 4, and 4A; visual
indicator assembly 21 will be in the position illustrated in FIGS.
2, 6, 6A, and 7. Referring to FIG. 2, dart 33 will be placed into
launcher bore 27 and an end of dart 33 will rest on release rod 63
(FIG. 4). As shown in FIG. 2, a plug 125 will be placed within
launcher bore 27 behind dart 33 to limit entry of undesired objects
into launcher bore 27 and prevent release of fluid from launcher
bore 27. As shown in FIGS. 2, 6, 6A, and 7, flapper 83 will extend
into launcher bore 27 perpendicular to axis 29 of launcher bore 27
so that a flat portion of flapper 83 may contact an object moving
through launcher bore 27. Similarly, arm 85 will be perpendicular
to launcher bore 27. Pressure passage 67 will equalize pressure
between annular passage 69 and launcher bore 27 to prevent
hydraulic pressure in launcher bore 27 from acting on release rod
63 to cause premature release. Plunger 115 of FIG. 8 will be
positioned within pre-launch detent 123.
[0044] When release of dart 33 is desired, pressure will be
supplied to port 47 to act on piston head 45. This will result in
movement of piston 41 from the position shown in FIG. 3 to a
position where piston head 45 is proximate to port 49. As shown in
FIG. 5, this will result in movement of release rod 63 from
launcher bore 27 to allow dart 33 to move from launcher bore 27
into central bore 25. Indicator screw 57 will move from the
position proximate to launcher body 17 as shown in FIG. 4A to the
position spaced further from launcher body 17 as shown in FIG.
5A.
[0045] As dart 33 moves through launcher bore 27, it will contact
flapper 83 as shown in FIG. 7. Flapper 83 will minimally resist
movement of dart 33; thus, dart 33 will cause flapper 83, and
consequently indicator rod 77 to rotate as dart 33 moves past
visual indicator assembly 21. As indicator rod 77 rotates, plunger
105 will release from pre-launch detent 123 and bring post-launch
detent 123' proximate to plunger 105, allowing exterior end 115 of
plunger 105 to move into post-launch detent 123' as shown in FIG.
9B. This will arrest rotation of indicator rod 77 in the position
shown in FIGS. 9 and 9A. As shown, arm 85 will undergo a ninety
degree rotation so that arm 83 will be generally parallel to
launcher bore 27 as shown in FIG. 5. This ninety degree rotation
will indicate to an operator that dart 33 has successfully moved
from launcher bore 27 into central bore 25 for further movement
down a coupled drill string.
[0046] Accordingly, the disclosed embodiments provide numerous
advantages. For example, the disclosed embodiments provide a dart
launcher capable of launching darts, balls, or plugs of different
sizes. In addition, the disclosed embodiments provide a pressure
balancing system to prevent premature release of the dart that may
be caused by hydraulic pressure within the launcher bore. The
disclosed embodiments also allow for maintenance of circulation
pressure within the coupled tubing string while dropping the dart.
Still further, the disclosed embodiments provide a visual indicator
of a successful dart launch, that requires no external energy
source, can be seen from a distance, and is easy to assemble.
[0047] It is understood that the present invention may take many
forms and embodiments. Accordingly, several variations may be made
in the foregoing without departing from the spirit or scope of the
invention. Having thus described the present invention by reference
to certain of its preferred embodiments, it is noted that the
embodiments disclosed are illustrative rather than limiting in
nature and that a wide range of variations, modifications, changes,
and substitutions are contemplated in the foregoing disclosure and,
in some instances, some features of the present invention may be
employed without a corresponding use of the other features. Many
such variations and modifications may be considered obvious and
desirable by those skilled in the art based upon a review of the
foregoing description of preferred embodiments. Accordingly, it is
appropriate that the appended claims be construed broadly and in a
manner consistent with the scope of the invention.
* * * * *