U.S. patent application number 10/411506 was filed with the patent office on 2004-11-04 for detonating cord interrupt device and method for transporting an explosive device.
Invention is credited to Finsterwald, Mark A..
Application Number | 20040216632 10/411506 |
Document ID | / |
Family ID | 33309481 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216632 |
Kind Code |
A1 |
Finsterwald, Mark A. |
November 4, 2004 |
Detonating cord interrupt device and method for transporting an
explosive device
Abstract
A detonating cord interrupt device (140) is positionable between
two segments of detonating cord (126, 134). The detonating cord
interrupt device (140) includes a housing (130), a first booster
(128) at least partially disposed within the housing (130) and a
second booster (132) at least partially disposed within the housing
(130) and having a spaced apart relationship with the first booster
(128). A detonation transfer interrupt member (138) is removably
positionable within the housing (130) in the space between the
first and second boosters (128, 132) such that the transfer of a
detonation from one of the first and the second boosters (128, 132)
to the other of the first and the second boosters (128, 132) is
prevented when the detonation transfer interrupt member (138) is
positioned within the housing (130).
Inventors: |
Finsterwald, Mark A.;
(Alvarado, TX) |
Correspondence
Address: |
LAWRENCE R. YOUST
DANAMRAJ & YOUST, P.C.
5910 NORTH CENTRAL EXPRESSWAY
SUITE 1450
DALLAS
TX
75206
US
|
Family ID: |
33309481 |
Appl. No.: |
10/411506 |
Filed: |
April 10, 2003 |
Current U.S.
Class: |
102/310 ;
102/275.12 |
Current CPC
Class: |
F42D 1/043 20130101 |
Class at
Publication: |
102/310 ;
102/275.12 |
International
Class: |
F42B 001/00 |
Claims
1. A perforating gun assembly comprising: a plurality of shaped
charges positioned within a charge carrier; a detonating cord
operably coupled to the shaped charges; a detonator operable to
initiate a detonation within the detonating cord; and a detonating
cord interrupt device positioned within the detonating cord between
the detonator and the shaped charges.
2. The perforating gun assembly as recited in claim 1 wherein the
charge carrier is a ported carrier having ports substantially
radially aligned with the shaped charges and a port axially aligned
with the detonating cord interrupt device, the ports having port
plugs positioned therein prior to firing the perforating gun
assembly that provide a fluid seal with the ports.
3. The perforating gun assembly as recited in claim 1 wherein the
detonating cord has a first segment and a second segment and
wherein the detonating cord interrupt device is positioned between
the first and second segments.
4. The perforating gun assembly as recited in claim 3 wherein the
detonating cord interrupt device further comprises a first booster
operably associated with the first segment of the detonating cord
and a second booster operably associated with the second segment of
the detonating cord, the first and second boosters at least
partially disposed within a housing and having a spaced apart
relationship with one another.
5. The perforating gun assembly as recited in claim 4 wherein the
first booster is securably coupled to the first ,segment of the
detonating cord by crimping, the second booster is securably
coupled to the second segment of the detonating cord by crimping
and the first and second boosters are securably coupled to the
housing by crimping.
6. The perforating gun assembly as recited in claim 4 wherein the
detonating cord interrupt device further comprises a detonation
transfer interrupt member removably positionable within the housing
in the space between the first and second boosters.
7. The perforating gun assembly as recited in claim 6 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
prevented when the detonation transfer interrupt member is
positioned within the housing.
8. The perforating gun assembly as recited in claim 6 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
allowed when the detonation transfer interrupt member is not
positioned within the housing.
9. The perforating gun assembly as recited in claim 6 wherein the
detonation transfer interrupt member extends transversely through
an opening in the housing.
10. The perforating gun assembly as recited in claim 6 wherein the
detonation transfer interrupt member further comprises a
substantially cylindrical member.
11-26. (Cancelled)
27. A perforating gun assembly comprising: a plurality of shaped
charges positioned within a charge carrier; a detonating cord
having first and second segments, the second segment of the
detonating cord operably coupled to the shaped charges; a detonator
operable to initiate a detonation within the first segment of the
detonating cord; and a detonating cord interrupt device positioned
between the first and second segments of the detonating cord, the
detonating cord interrupt device having a housing, a first booster
operably associated with the first segment of the detonating cord,
a second booster operably associated with the second segment of the
detonating cord, the first and second boosters at least partially
disposed within the housing and having a spaced apart relationship
with one another and a detonation transfer interrupt member
removably positionable within the housing in the space between the
first and second boosters, such that the transfer of a detonation
from the first booster to the second booster is prevented when the
detonation transfer interrupt member is positioned within the
housing and the transfer of a detonation from the first booster to
the second booster is allowed when the detonation transfer
interrupt member is not positioned within the housing.
28. The perforating gun assembly as recited in claim 27 wherein the
charge carrier is a ported carrier having ports substantially
radially aligned with the shaped charges and a port axially aligned
with the detonating cord interrupt device, the ports having port
plugs positioned therein prior to firing the perforating gun
assembly that provide a fluid seal with the ports.
29. The perforating gun assembly as recited in claim 27 wherein the
first booster is securably coupled to the first segment of the
detonating cord by crimping, the second booster is securably
coupled to the second segment of the detonating cord by crimping
and the first and second boosters are securably coupled to the
housing by crimping.
30. The perforating gun assembly as recited in claim 27 wherein the
detonation transfer interrupt member extends transversely through
an opening in the housing.
31. The perforating gun assembly as recited in claim 27 wherein the
detonation transfer interrupt member further comprises a
substantially cylindrical member.
32-41. (Cancelled)
42. A perforating gun assembly comprising: a plurality of shaped
charges positioned within a charge carrier; a detonating cord
operably coupled to the shaped charges; a detonator operable to
initiate the detonating cord; and a detonating cord interrupt
device positioned within the detonating cord between the detonator
and the shaped charges, the detonating cord interrupt device having
a detonation transfer interrupt member that is removably
positionable therein to selectively prevent and allow a detonation
to be transferred thereacross.
43. The perforating gun assembly as recited in claim 42 wherein the
charge carrier is a ported carrier having ports substantially
radially aligned with the shaped charges and a port axially aligned
with the detonating cord interrupt device, the ports having port
plugs positioned therein prior to firing the perforating gun
assembly that provide a fluid seal with the ports.
44. The perforating gun assembly as recited in claim 42 wherein the
detonating cord has a first segment and a second segment and
wherein the detonating cord interrupt device is positioned between
the first and second segments.
45. The perforating gun assembly as recited in claim 44 wherein the
detonating cord interrupt device further comprises a first booster
operably associated with the first segment of the detonating cord
and a second booster operably associated with the second segment of
the detonating cord, the first and second boosters at least
partially disposed within a housing and having a spaced apart
relationship with one another.
46. The perforating gun assembly as recited in claim 45 wherein the
first booster is securably coupled to the first segment of the
detonating cord by crimping, the second booster is securably
coupled to the second segment of the detonating cord by crimping
and the first and second boosters are securably coupled to the
housing by crimping.
47. The perforating gun assembly as recited in claim 45 wherein the
detonation transfer interrupt member is removably positionable
within the housing in the space between the first and second
boosters.
48. The perforating gun assembly as recited in claim 47 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
prevented when the detonation transfer interrupt member is
positioned within the housing.
49. The perforating gun assembly as recited in claim 47 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
allowed when the detonation transfer interrupt member is not
positioned within the housing.
50. The perforating gun assembly as recited in claim 47 wherein the
detonation transfer interrupt member extends transversely through
an opening in the housing.
51. The perforating gun assembly as recited in claim 47 wherein the
detonation transfer interrupt member further comprises a
substantially cylindrical member.
52. A perforating gun assembly having a plurality of shaped charges
positioned within a charge carrier, a detonating cord operably
coupled to the shaped charges and a detonator operable to initiate
the detonating cord, the perforating gun assembly comprising: a
detonating cord interrupt device positioned within the detonating
cord between the detonator and the shaped charges, the detonating
cord interrupt device having a detonation transfer interrupt member
that is removably positionable therein to selectively prevent and
allow a detonation to be transferred thereacross.
53. The perforating gun assembly as recited in claim 52 wherein the
charge carrier is a ported carrier having ports substantially
radially aligned with the shaped charges and a port axially aligned
with the detonating cord interrupt device, the ports having port
plugs positioned therein prior to firing the perforating gun
assembly that provide a fluid seal with the ports.
54. The perforating gun assembly as recited in claim 52 wherein the
detonating cord has a first segment and a second segment and
wherein the detonating cord interrupt device is positioned between
the first and second segments.
55. The perforating gun assembly as recited in claim 54 wherein the
detonating cord interrupt device further comprises a first booster
operably associated with the first segment of the detonating cord
and a second booster operably associated with the second segment of
the detonating cord, the first and second boosters at least
partially disposed within a housing and having a spaced apart
relationship with one another.
56. The perforating gun assembly as recited in claim 55 wherein the
first booster is securably coupled to the first segment of the
detonating cord by crimping, the second booster is securably
coupled to the second segment of the detonating cord by crimping
and the first and second boosters are securably coupled to the
housing by crimping.
57. The perforating gun assembly as recited in claim 55 wherein the
detonation transfer interrupt member is removably positionable
within the housing in the space between the first and second
boosters.
58. The perforating gun assembly as recited in claim 57 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
prevented when the detonation transfer interrupt member is
positioned within the housing.
59. The perforating gun assembly as recited in claim 57 wherein the
transfer of a detonation from one of the first and the second
boosters to the other of the first and the second boosters is
allowed when the detonation transfer interrupt member is not
positioned within the housing.
60. The perforating gun assembly as recited in claim 57 wherein the
detonation transfer interrupt member extends transversely through
an opening in the housing.
61. The perforating gun assembly as recited in claim 57 wherein the
detonation transfer interrupt member further comprises a
substantially cylindrical member.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates, in general, to perforating a cased
wellbore that traverses a subterranean hydrocarbon bearing
formation and, in particular, to a detonating cord interrupt device
for preventing the premature detonation of the shaped charges
within a perforating gun assembly during transportation.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its
background will be described with reference to perforating a
subterranean formation with a perforating gun assembly, as an
example.
[0003] After drilling a section of a subterranean wellbore that
traverses a formation, individual lengths of relatively large
diameter metal tubulars are typically secured together to form a
casing string that is positioned within the wellbore. This casing
string increases the integrity of the wellbore and provides a path
for producing fluids from the producing intervals to the surface.
Conventionally, the casing string is cemented within the wellbore.
To produce fluids into the casing string, hydraulic openings or
perforations must be made through the casing string, the cement and
a short distance into the formation.
[0004] Typically, these perforations are created by detonating a
series of shaped charges that are disposed within the casing string
and are positioned adjacent to the formation. Specifically, one or
more charge carriers are loaded with shaped charges that are
connected with a detonator via a detonating cord. The charge
carriers are then connected within a tool string that is lowered
into the cased wellbore at the end of a tubing string, wireline,
slick line, coil tubing or other conveyance. Once the charge
carriers are properly positioned in the wellbore such that the
shaped charges are adjacent to the formation to be perforated, the
shaped charges may be fired. If more than one downhole zone is to
be perforated, a select fire perforating gun assembly may be used
such that once the first zone is perforated, subsequent zones may
be perforated by repositioning and firing the previously unfired
shaped charges without tripping out of the well.
[0005] The shaped charges used to perforate the casing include high
explosives and must therefore be handled with extreme caution. For
example, it is imperative that the high explosives are not
prematurely initiated causing the shaped charge to detonate.
Accordingly, in the interest of safety and due to governmental
regulations relating to the transportation of explosive devices,
perforating gun assemblies are typically not armed, i.e., the
detonators are not installed, until the perforating gun assembly
arrives at the rig site.
[0006] It has been found, however, that installing detonators in
the perforating gun assembly at the rig site has several drawbacks.
For example, the person installing the detonators is commonly under
a time constraint to complete to the installation as rig time is
very expensive. In addition, the rig environment, such as weather
conditions, work area, lighting and the like, may not be as
conducive as the manufacturer's shop environment for the intricate
assembly required during the installation of the detonators.
Furthermore, the level of skill of the person installing the
detonators at the rig site may not be as great as that of a
technician in the manufacturer's shop. These inherent limitations
of the rig environment have lead to mistakes being made in the
installation of detonators into perforating gun assemblies
resulting in the failure of certain perforating gun assemblies to
fire.
[0007] Therefore a need has arisen for an apparatus and method that
provide for the safe transportation of an armed perforating gun
assembly such that the intricate work of installing the detonators
may be performed in the manufacturer's shop as opposed to the rig
site. A need has also arisen for such an apparatus and method that
prevent the premature detonation of the shaped charges in the armed
perforating gun assembly. Further, a need has arisen for such an
apparatus and method that minimize the required on site preparation
of the armed perforating gun assembly.
SUMMARY OF THE INVENTION
[0008] The present invention disclosed herein comprises a
perforating gun assembly that provides for the safe transportation
of an armed perforating gun assembly such that the intricate work
of installing the detonators may be performed in the manufacturer's
shop as opposed to the rig site. To achieve this result, the
perforating gun assembly of the present invention uses a detonating
cord interrupt device that prevents the premature detonation of the
shaped charges in the armed perforating gun assembly. In addition,
the detonating cord interrupt device requires minimal on site
manipulation to allow a planned detonation of the shaped
charges.
[0009] The detonating cord interrupt device of the present
invention comprises a housing, a first booster at least partially
disposed within the housing, a second booster at least partially
disposed within the housing and having a spaced apart relationship
with the first booster and a detonation transfer interrupt member
removably positionable within the housing in the space between the
first and second boosters.
[0010] In one embodiment, the detonation transfer interrupt member
extends transversely through an opening in the housing. In this
embodiment, the detonation transfer interrupt member may be a
substantially cylindrical member that is inserted through a round
opening in the housing. The detonation transfer interrupt member
may be constructed from a variety of materials such as metals,
polymers, elastomers and combination thereof.
[0011] In operation, the detonating cord interrupt device prevents
the transfer of a detonation from one of the boosters to the other
booster when the detonation transfer interrupt member is positioned
within the housing. Likewise, the detonating cord interrupt device
allows the transfer of a detonation from one of the boosters to the
other booster when the detonation transfer interrupt member is not
positioned within the housing.
[0012] The detonating cord interrupt device may be positioned
within a detonating cord to prevent the premature propagation of a
detonation wave through the detonating cord. For example, the
detonating cord interrupt device may be positioned between a first
and a second segment of a detonating cord. In this configuration,
the first booster is operably associated with the first segment of
detonating cord and the second booster operably associated with the
second segment of detonating cord. More specifically, the first
booster may be securably coupled to the first segment of detonating
cord by crimping and the second booster may be securably coupled to
the second segment of detonating cord by crimping. Likewise, the
first and second boosters may be securably coupled to the housing
by crimping.
[0013] Such an arrangement, may be used within a perforating gun
assembly such that the perforating gun assembly may be armed prior
to transportation. The perforating gun assembly of the present
invention comprises a plurality of shaped charges positioned within
a charge carrier and a detonating cord having first and second
segments. The second segment of the detonating cord is operably
coupled to the shaped charges. A detonator is operably coupled to
the first segment of the detonating cord and is operable to
initiate a detonation within the first segment of the detonating
cord. The detonating cord interrupt device is positioned between
the first and second segments of the detonating cord to prevent a
detonation of the shaped charges in the event of a premature
initiation of the detonator.
[0014] The charge carrier of the perforating gun assembly may be a
ported carrier having ports substantially radially aligned with the
shaped charges and a port axially aligned with the detonating cord
interrupt device. Port plugs are secured within the ports to
provide a fluid seal and prevent any fluids from entering the
perforating gun assembly prior to firing.
[0015] In another aspect, the present invention comprises a method
for preventing the detonation of shaped charges in an armed
perforating gun assembly. The method includes positioning a
plurality of shaped charges within a charge carrier, operably
coupling a detonating cord to the shaped charges, operably coupling
a detonator to the detonating cord and positioning a detonating
cord interrupt device within the detonating cord between the
detonator and the shaped charges.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For a more complete understanding of the features and
advantages of the present invention, reference is now made to the
detailed description of the invention along with the accompanying
figures in which corresponding numerals in the different figures
refer to corresponding parts and in which:
[0017] FIG. 1 is schematic illustration of an offshore oil and gas
platform operating a perforating gun assembly of the present
invention;
[0018] FIG. 2 is a side view partially cut away of a perforating
gun assembly of the present invention positioned within a
wellbore;
[0019] FIG. 3 is a side view of a detonator, two segments of
detonating cord and a detonating cord interrupt device of the
present invention;
[0020] FIG. 4 is a cross sectional view of detonating cord
interrupt device of the present invention positioned between two
segments of detonating cord prior to a premature detonation;
[0021] FIG. 5 is a cross sectional view of detonating cord
interrupt device of the present invention positioned between two
segments of detonating cord following a premature detonation;
[0022] FIG. 6 is a cross sectional view of detonating cord
interrupt device of the present invention positioned between two
segments of detonating cord prior to a planned detonation;
[0023] FIG. 7 is a cross sectional view of detonating cord
interrupt device of the present invention positioned between two
segments of detonating cord following a planned detonation; and
[0024] FIG. 8 is a cross sectional view of an alternate embodiment
of a detonating cord interrupt device of the present invention
positioned between two segments of detonating cord.
DETAILED DESCRIPTION OF THE INVENTION
[0025] While the making and using of various embodiments of the
present invention are discussed in detail below, it should be
appreciated that the present invention provides many applicable
inventive concepts which can be embodied in a wide variety of
specific contexts. The specific embodiments discussed herein are
merely illustrative of specific ways to make and use the invention,
and do not delimit the scope of the present invention.
[0026] Referring initially to FIG. 1, a perforating gun assembly
adapted for use in a wellbore operating from an offshore oil and
gas platform is schematically illustrated and generally designated
10. A semi-submersible platform 12 is centered over a submerged oil
and gas formation 14 located below sea floor 16. A subsea conduit
18 extends from deck 20 of platform 12 to wellhead installation 22
including blowout preventers 24. Platform 12 has a hoisting
apparatus 26 and a derrick 28 for raising and lowering pipe
strings.
[0027] A wellbore 36 extends through the various earth strata
including formation 14. Casing 38 is cemented within wellbore 36 by
cement 40. When it is desired to perforate casing 38 adjacent to
formation 14, a perforating gun assembly 42 is lowered into casing
38 via conveyance 44 such as a wireline, electric line or coiled
tubing. Thereafter, an electric signal is sent to a detonator 46
which initiates the detonation of the shaped charges that are
disposed within perforating gun assembly 42. Upon detonation,
perforations are created that extend outwardly through casing 38,
cement 40 and into formation 14.
[0028] Even though FIG. 1 depicts a vertical well, it should be
noted by one skilled in the art that the perforating gun assembly
of the present invention is equally well-suited for use in wells
having other geometries such as deviated wells, inclined wells or
horizontal wells. Also, even though FIG. 1 depicts an offshore
operation, it should be noted by one skilled in the art that the
perforating gun assembly of the present invention is equally
well-suited for use in onshore operations.
[0029] Referring now to FIG. 2, therein is depicted a perforating
gun assembly 60 positioned in a wellbore 62 that penetrates
formation 64. A casing 66 lines wellbore 62 and is secured in
position by cement 68. A conveyance 70 is coupled to perforating
gun assembly 60 at a cable head 72. A collar locator 74 is
positioned below cable head 72 to aid in the positioning of
perforating gun assembly 60 in wellbore 62.
[0030] A fluid such as drilling fluid (not shown) fills the annular
region between perforating gun assembly 60 and casing 66. In the
illustrated embodiment, perforating gun assembly 60 has a ported
carrier 80 having port plugs 82 positioned therein that create a
fluid seal and prevent any wellbore fluids from entering
perforating gun assembly 60. Radially aligned with port plugs 82 is
a respective one of a plurality of shaped charges, such as shaped
charge 86. Each of the shaped charges includes an outer housing,
such as housing 88 of shaped charge 86, and a liner, such as liner
90 of shaped charge 86. Disposed between each housing and liner is
a quantity of high explosive.
[0031] In the illustrated embodiment, the shaped charges are
retained within carrier 80 by a support member 92 which includes an
outer charge holder sleeve 94 and an inner charge holder sleeve 96.
In this configuration, outer charge holder sleeve 94 supports the
discharge ends of the shaped charges, while inner charge holder
sleeve 96 supports the initiation ends of the shaped charges.
Disposed within inner tube 96 is a detonating cord 98, such as a
primacord, which is operable to detonate the shaped charges. In the
illustrated embodiment, the initiation ends of the shaped charges
extend across the cental longitudinal axis of perforating gun
assembly 60 allowing detonating cord 98 to connect to the high
explosive within the shaped charges through an aperture defined at
the apex of the housings of the shaped charges.
[0032] Each of the shaped charges is longitudinally and radially
aligned with a port plug 82 in carrier 80 when perforating gun
assembly 60 is fully assembled. In the illustrated embodiment, the
shaped charges are arranged in a spiral pattern such that each
shaped charge is disposed on its own level or height and is to be
individually detonated so that only one shaped charge is fired at a
time. It should be noted, however, by those skilled in the art that
alternate arrangements of shaped charges may be used, including
cluster type designs wherein more than one shaped charge is at the
same level and is detonated at the same time, without departing
from the principles of the present invention.
[0033] Perforating gun assembly 60 also includes a detonator
subassembly 100. Detonator subassembly 100 has a ported housing 102
that receives a port plug 104. Disposed within detonator
subassembly 100 is a detonator 106 that is coupled to an electrical
energy source via electrical wire 108. Detonator 106 may be any
type of detonator that is suitable for initiating a detonation in a
detonating cord as the present invention is detonator independent,
such detonators being of the type that are well known in the art or
subsequently discovered. Detonator 106 is coupled to a segment of
detonating cord 110. Positioned between detonating cord 110 and
detonating cord 98, which extends into detonator subassembly 100
from carrier 80, is a detonating cord interrupt device 112.
[0034] Detonating cord interrupt device 112 is used to selectively
prevent and allow the propagation of a detonation from detonating
cord 110 to detonating cord 98. More specifically, when perforating
gun assembly 60 is assembled in the shop, detonator 106 is
installed within perforating gun assembly 60 along with the shaped
charges. Importantly, for safety during transportation of the armed
perforating gun assembly 60 from the shop to the rig site,
detonating cord interrupt device 112 is positioned in its
detonation interpret configuration within the explosive train
between detonator 106 and the shaped charges. Accordingly, even if
detonator 106 were to prematurely initiate a detonation, detonating
cord interrupt device 112 would prevent the detonation wave from
transferring from detonating cord 110 to detonating cord 98.
[0035] Once the armed perforating gun assembly 60 has been safely
transported to the rig site, port plug 104 is removed such that a
technician can reconfigure detonating cord interrupt device 112
from its detonation interpret configuration to its non detonation
interrupt configuration. Thereafter, perforating gun assembly 60
may be attached to a conveyance and run downhole to the desired
location. To detonate the shaped charges, an electrical signal is
sent to detonator 106 via electrical wire 108 that initiates a
detonation within detonating cord 110. The detonation transfers
from detonating cord 110 to detonating cord 98, as explained in
greater detail below, by passing through detonating cord interrupt
device 112 in its non detonation interrupt configuration. The
detonation wave then progresses through detonating cord 98 to
initiate the detonation of the shaped charges, thereby perforating
the well.
[0036] Even though a single perforating gun assembly is depicted in
FIG. 2, it should be appreciated by those skilled in the art that
any number of perforating gun assemblies may be included in the
tool string and are considered within the scope of the present
invention as the number of perforating gun assemblies will be
dependent upon the length of the interval or intervals being
perforated as well as the number of intervals being perforated in a
single trip using, for example, select fire perforating gun
assemblies which will require multiple detonating cord interrupt
devices. Also, even though perforating gun assembly 60 is depicted
in a bottom up firing configuration, it should be understood by
those skilled in the art that the present invention in equally
well-suited for use in perforating gun assemblies having a top down
firing configuration.
[0037] Referring next to FIG. 3, therein is presented an enlarged
view of a first portion of an explosive train according to the
present invention that is generally designated 120. Explosive train
120 includes detonator 122 that is coupled to an electrical input
line 124 and to a segment of detonating cord 126. On the opposite
end of detonating cord 126 is a booster 128 that is securably
coupled to detonating cord 126 by crimping. The opposite end of
booster 128 (not visible in FIG. 3) extends into housing 130 and is
secured therein by crimping housing 130. Housing 130 may be
constructed from a variety of materials including metals such as
steels and aluminum, polymers or other suitably durable material. A
booster 132 extends into the opposite end of housing 130 and is
similarly secured therein by crimping housing 130. Extending from
the opposite end of booster 132 is a segment of detonating cord
134. Housing 130 has an opening 136 through which a detonation
transfer interrupt member 138 transversely extends. Detonation
transfer interrupt member 138 may be constructed from any suitable
material such as metals including steels, copper, aluminum and the
like, polymers, elastomers or combination thereof and the like.
Together, housing 130, boosters 128, 132 and detonation transfer
interrupt member 138 form detonating cord interrupt device 140.
Even though the coupling of the detonating cords to the boosters
and the boosters to the housing has been depicted as crimping, it
should be noted by those skilled in the art that other techniques
could alternatively be used for such coupling, including, but not
limited to, use of adhesives, a friction fit or combinations
thereof and the like.
[0038] As best seen in FIG. 4, detonating cord interrupt device 140
is in its detonation interrupt configuration prior to the
detonation of either detonating cord 126 or detonating cord 134. In
the illustrated embodiment, detonating cord 126 includes explosive
142, booster 128 includes explosive 144, detonating cord 134
includes explosive 146 and booster 132 includes explosive 148. As
stated above, if one of the detonating cords were to be detonated
when detonating cord interrupt device 140 is in its detonation
interrupt configuration wherein detonation transfer interrupt
member 138 is positioned with opening 136, the detonation would not
transfer to the opposing detonating cord.
[0039] Specifically and as depicted in FIG. 5 in an idealized
manner, following the detonation of detonating cord 126 and booster
128, the detonation does not transfer to booster 132, detonating
cord 134 or any other explosive device in the downstream explosive
train as detonation transfer interrupt member 138 is positioned
within opening 136 of housing 130. As such, detonating cord
interrupt device 140 prevents the propagation of the detonation
thereacross.
[0040] Once the perforating gun assembly including detonating cord
interrupt device 140 is ready to be fired, detonation transfer
interrupt member 138 is removed from opening 136 in housing 130, as
best seen in FIG. 6. Thereafter and as depicted in FIG. 7 in an
idealized manner, following the detonation of detonating cord 126
and booster 128, the detonation transfers to the facing booster
132, detonating cord 134 and any other explosive device in the
downstream explosive train as detonation transfer interrupt member
138 is not positioned within opening 136 of housing 130. As such,
in this configuration, detonating cord interrupt device 140 allows
the propagation of the detonation thereacross.
[0041] Even though FIGS. 4-7 have depicted a gap between the ends
of boosters 128, 132 and detonating cord interrupt device 140, it
should be understood by those skilled in the art that the optimal
distance between the facing boosters will depend on a variety of
factors such as the type of booster used, the diameter of housing
130 and the like. For example, it may be desirable in some cases to
have the ends of the facing boosters contact the detonation
transfer interrupt member when the detonation transfer interrupt
member is positioned with the housing.
[0042] Specifically, as depicted in FIG. 8, detonating cord
interrupt device 240 includes a booster 228 that is connected to a
segment of detonating cord 226. Likewise, booster 232 is connected
to a segment of detonating cord 234. Boosters 228, 232 each extend
into housing 230 such that their respective ends contact detonation
transfer interrupt member 238 if detonation transfer interrupt
member 238 is positioned with opening 236 of housing 230. As
illustrated, detonating cord 226 includes explosive 242, booster
228 includes explosive 244, detonating cord 234 includes explosive
246 and booster 232 includes explosive 248. Detonating cord
interrupt device 240 selectively prevents and allows the transfer
of a detonation thereacross as described above with reference to
detonating cord interrupt device 140.
[0043] Even though FIGS. 3-8 have depicted the detonation transfer
interrupt member as being cylindrical and the opening in the
housing of the detonating cord interrupt device as being round, it
should be clearly understood by those skilled in the art that
detonation transfer interrupt members having alternate shapes being
positionable in correspondingly configured openings in the housing
of the detonating cord interrupt devices is contemplated and
considered within the scope of the present invention. Such other
shapes including, but not limited to, detonation transfer interrupt
members having square cross sections, rectangular cross sections,
or other polygon shaped cross sections, oval cross sections or
other symmetric or non symmetric cross sections.
[0044] While this invention has been described with reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments as well as other
embodiments of the invention, will be apparent to persons skilled
in the art upon reference to the description. It is, therefore,
intended that the appended claims encompass any such modifications
or embodiments.
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