U.S. patent application number 13/533600 was filed with the patent office on 2013-02-28 for perforating gun with internal shock mitigation.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. The applicant listed for this patent is John D. BURLESON, Edwin A. EATON, Timothy S. GLENN, John H. HALES, John P. RODGERS, Marco SERRA. Invention is credited to John D. BURLESON, Edwin A. EATON, Timothy S. GLENN, John H. HALES, John P. RODGERS, Marco SERRA.
Application Number | 20130048376 13/533600 |
Document ID | / |
Family ID | 47742016 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130048376 |
Kind Code |
A1 |
RODGERS; John P. ; et
al. |
February 28, 2013 |
PERFORATING GUN WITH INTERNAL SHOCK MITIGATION
Abstract
A perforating gun can include at least one explosive component,
and a shock mitigation device including a shock reflector which
indirectly reflects a shock wave produced by detonation of the
explosive component. Another perforating gun can include a gun
housing, at least one explosive component, and a shock mitigation
device in the gun housing. The shock mitigation device can include
a shock attenuator which attenuates a shock wave produced by
detonation of the explosive component. Yet another perforating gun
can include a shock mitigation device with an explosive material
which produces a shock wave that interacts with another shock wave
produced by detonation of an explosive component in a gun
housing.
Inventors: |
RODGERS; John P.; (Roanoke,
TX) ; GLENN; Timothy S.; (Dracut, MA) ; SERRA;
Marco; (Winterthur, CH) ; EATON; Edwin A.;
(Grapevine, TX) ; BURLESON; John D.; (Denton,
TX) ; HALES; John H.; (Choctaw, OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RODGERS; John P.
GLENN; Timothy S.
SERRA; Marco
EATON; Edwin A.
BURLESON; John D.
HALES; John H. |
Roanoke
Dracut
Winterthur
Grapevine
Denton
Choctaw |
TX
MA
TX
TX
OK |
US
US
CH
US
US
US |
|
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Houston
TX
|
Family ID: |
47742016 |
Appl. No.: |
13/533600 |
Filed: |
June 26, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13493327 |
Jun 11, 2012 |
|
|
|
13533600 |
|
|
|
|
Current U.S.
Class: |
175/4.6 ;
175/2 |
Current CPC
Class: |
E21B 43/1195
20130101 |
Class at
Publication: |
175/4.6 ;
175/2 |
International
Class: |
E21B 43/116 20060101
E21B043/116; E21B 43/11 20060101 E21B043/11 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2011 |
US |
PCT/US11/49882 |
Claims
1-12. (canceled)
13. A perforating gun, comprising: a gun housing; at least one
explosive component; and a shock mitigation device in the gun
housing, the shock mitigation device including a shock attenuator
which attenuates a shock wave produced by detonation of the
explosive component.
14. The perforating gun of claim 13, wherein the shock mitigation
device reflects the attenuated shock wave.
15. The perforating gun of claim 13, wherein the shock mitigation
device absorbs, breaks-up, scatters or disperses the shock
wave.
16. The perforating gun of claim 13, wherein the shock attenuator
comprises layers of resilient and non-resilient materials.
17. The perforating gun of claim 13, wherein the shock attenuator
comprises variations in acoustic impedance.
18-39. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/493,327 filed on 11 Jun. 2012 which claims the benefit under
35 USC .sctn.119 of the filing date of International Application
Serial No. PCT/US11/49882 filed 31 Aug. 2011. The entire disclosure
of these prior applications are incorporated herein by this
reference.
BACKGROUND
[0002] The present disclosure relates generally to equipment
utilized and operations performed in conjunction with a
subterranean well and, in an embodiment described herein, more
particularly provides for mitigating shock produced by well
perforating.
[0003] Shock absorbers have been used in the past to absorb shock
produced by detonation of perforating guns in wells. Unfortunately,
prior shock absorbers have had only very limited success.
Therefore, it will be appreciated that improvements are needed in
the art of mitigating shock produced by perforating strings.
SUMMARY
[0004] In carrying out the principles of this disclosure, a
perforating gun is provided with improvements in the art. One
example is described below in which a shock mitigation device in a
perforating gun reflects shock produced by detonation of the
perforating gun. Another example is described below in which the
shock mitigation device attenuates the shock. Yet another example
is described in which the device produces a shock wave that
interacts with a shock wave produced by detonation of the
perforating gun.
[0005] In one aspect, a perforating gun is provided to the art by
this disclosure. In one example, the perforating gun can include at
least one explosive component, and a shock mitigation device with a
shock reflector which indirectly reflects a shock wave produced by
detonation of the explosive component.
[0006] In another aspect, a perforating gun is described below
which, in one example, can include a gun housing, at least one
explosive component, and a shock mitigation device in the gun
housing. The shock mitigation device includes a shock attenuator
which attenuates a shock wave produced by detonation of the
explosive component.
[0007] In yet another aspect, the disclosure below describes a
perforating gun in which a shock mitigation device includes an
explosive material which produces a shock wave that interacts with
another shock wave produced by detonation of an explosive component
in a gun housing.
[0008] These and other features, advantages and benefits will
become apparent to one of ordinary skill in the art upon careful
consideration of the detailed description of representative
embodiments of the disclosure hereinbelow and the accompanying
drawings, in which similar elements are indicated in the various
figures using the same reference numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a representative partially cross-sectional view of
a well system and associated method which can embody principles of
this disclosure.
[0010] FIG. 2 is a representative cross-sectional view of a
perforating gun which may be used in the system and method of FIG.
1, and which can embody principles of this disclosure.
[0011] FIGS. 3-6 are representative cross-sectional views of
additional configurations of a shock mitigating device in the
perforating gun.
DETAILED DESCRIPTION
[0012] Representatively illustrated in FIG. 1 is a system 10 for
use with a well, and an associated method, which can embody
principles of this disclosure. In the system 10, a perforating
string 12 is positioned in a wellbore 14 lined with casing 16 and
cement 18. Perforating guns 20 in the perforating string 12 are
positioned opposite predetermined locations for forming
perforations 22 through the casing 16 and cement 18, and outward
into an earth formation 24 surrounding the wellbore 14.
[0013] The perforating string 12 is sealed and secured in the
casing 16 by a packer 26. The packer 26 seals off an annulus 28
formed radially between the tubular string 12 and the wellbore 14.
A tubular string 34 (such as a work string, a production tubing
string, an injection string, etc.) may be interconnected above the
packer 26.
[0014] A firing head 30 is used to initiate firing or detonation of
the perforating guns 20 (e.g., in response to a mechanical,
hydraulic, electrical, optical or other type of signal, passage of
time, etc.), when it is desired to form the perforations 22.
Although the firing head 30 is depicted in FIG. 1 as being
connected above the perforating guns 20, one or more firing heads
may be interconnected in the perforating string 12 at any location,
with the location(s) preferably being connected to the perforating
guns by a detonation train.
[0015] At this point, it should be noted that the well system 10 of
FIG. 1 is merely one example of an unlimited variety of different
well systems which can embody principles of this disclosure. Thus,
the scope of this disclosure is not limited at all to the details
of the well system 10, its associated methods, the perforating
string 12, etc. described herein or depicted in the drawings.
[0016] For example, it is not necessary for the wellbore 14 to be
vertical, for there to be two of the perforating guns 20, or for
the firing head 30 to be positioned between the perforating guns
and the packer 26, etc. Instead, the well system 10 configuration
of FIG. 1 is intended merely to illustrate how the principles of
this disclosure may be applied to an example perforating string 12,
in order to mitigate the effects of a perforating event. These
principles can be applied to many other examples of well systems
and perforating strings, while remaining within the scope of this
disclosure.
[0017] It will be appreciated by those skilled in the art that
detonation of the perforating guns 20 produces shock which can
damage or unset the packer 26, or damage the tubular string 34,
firing head 30 or other components of the perforating string 12. In
the past, it has been common practice to attempt to absorb shock
produced by detonation of perforating guns, using shock absorbers
interconnected between components of perforating strings.
[0018] In contrast, the present inventors have conceived unique
ways of mitigating shock that do not involve the use of shock
absorbers between components of a perforating string. Of course,
shock absorbers could be used in combination with the concepts
described herein, while remaining within the scope of this
disclosure.
[0019] Referring additionally now to FIG. 2, an enlarged scale
cross-sectional view of a portion of one of the perforating guns 20
is representatively illustrated. This perforating gun 20 example
may be used in the well system 10 and method described above, or it
may be used in other well systems and methods.
[0020] As depicted in FIG. 2, the perforating gun 20 includes a
generally tubular gun housing 32 and explosive components (such as
detonating cord 36, perforating charges 38, detonation boosters 40,
etc.) in the gun housing. When the explosive components are
detonated (e.g., to form the perforations 22), shock waves 42 are
produced. For clarity of illustration, only one of the shock waves
42 is representatively depicted as a dashed line in FIG. 2.
[0021] To mitigate transmission of the shock wave 42 to other
components of a perforating string, the perforating gun 20 also
includes a shock mitigating device 44. In this example, the shock
mitigating device 44 is enclosed within the gun housing 32 and
functions to mitigate shock prior to the shock reaching any other
components of the perforating string. One advantage of this
arrangement is that such shock mitigating devices 44 can be used in
each of multiple perforating guns in a perforating string, so that
the shock produced by each perforating gun is internally
mitigated.
[0022] In the FIG. 2 example, the device 44 includes a shock
attenuator 46 which attenuates the shock wave 42. The attenuator 46
includes alternating layers of resilient material 48 (e.g.,
elastomers, rubber, fluoro-elastomers, etc.) and non-resilient
material 50 (e.g., soft metals such as aluminum, bronze, etc.,
crushable materials, etc.).
[0023] The attenuator 46 desirably decreases the amplitude of the
shock wave 42. However, other types of shock attenuators may be
used, if desired.
[0024] Preferably, the attenuator 46 provides sharply varying
acoustic impendances (e.g., due to the layers of resilient and
non-resilient materials 48, 50). For example, density, modulus,
and/or other characteristics of materials can affect their acoustic
impendances. By varying these characteristics from one layer to
another, corresponding varying acoustic impendances are obtained
(e.g., alternating layers of metal and poly-ether-ether-ketone,
etc.). Thus, the attenuator 46 can be constructed without
alternating layers of materials 48, 50 which are necessarily
resilient and non-resilient, but which have substantially different
acoustic impedances.
[0025] Referring additionally now to FIG. 3, the perforating gun
20, with another configuration of the shock mitigating device 44,
is representatively illustrated. The explosive components are not
depicted in FIG. 3 for clarity of illustration.
[0026] In this example, the shock mitigating device 44 includes a
shock reflector 52 which reflects the shock wave 42 produced by
detonation of the explosive components. Preferably, the reflected
shock wave(s) 54 are not reflected directly back in a direction
opposite to the direction of the shock wave 42. Instead, the shock
wave 42 is reflected outward by a convex generally conical surface
56 of the reflector 52. In other examples, the surface 56 is not
necessarily convex or conical, but preferably the surface does
indirectly reflect the shock wave 42.
[0027] Referring additionally now to FIG. 4, another configuration
of the shock mitigating device 44 is representatively illustrated.
In this example, the shock mitigating device 44 includes both the
reflector 52 of FIG. 3 and the attenuator 46 of FIG. 2 (albeit
formed into a generally conical shape).
[0028] This demonstrates that the features of the various examples
described herein can be combined as desired, for example, to obtain
benefits of those combined features. In the FIG. 4 example, the
shock wave 42 will be attenuated by the attenuator 46 prior to
being reflected by the surface 56 of the reflector 52.
[0029] Referring additionally now to FIG. 5, another configuration
of the shock mitigating device 44 is representatively illustrated.
In this example, the surface 56 of the reflector 52 comprises
multiple individual surfaces, instead of a single conical surface,
although the surfaces are still in a generally conical arrangement.
A shock attenuator 46 may be used with the reflector 52 (similar to
the combined attenuator 46 and reflector 52 in the device 44
configuration of FIG. 4), if desired.
[0030] The surfaces 56 cause many smaller (as compared to the
reflected shock wave in the FIG. 3 configuration) shock waves 54 to
be reflected in various directions. Preferably, the reflected shock
waves 54 are directed generally outward toward the gun housing 32,
and are not reflected directly back in the opposite direction of
the shock wave 42. Furthermore, it is preferable that the many
reflected shock waves 54 interfere with each other and at least
partially cancel or attenuate one another.
[0031] For example, the impact of the shock wavefront from the
blast can be spread over time to reduce peak amplitudes of shock in
the steel tools of the perforating string 12. The various incidence
angles can provide a reduction in energy transfer from the fluid to
the steel as more of the wave is reflected.
[0032] There is a distinction between the objective of reducing the
initial response (and peak stress) due to the incoming shock wave,
and reducing the multitude of reflections in the fluid or the
structure which result in repeated peak stresses over some
time.
[0033] The reflected waves in the fluid can be dispersed or
scattered in timing and direction to reduce reflected waves in the
fluid. The angled faces of the steel can also break up the internal
reflections of the waves within the steel part. This is in sharp
contrast to conventional perforating guns with a uniform flat
surface impacted at 90 degrees by an incoming wave, allowing for
maximum transmission of energy and peak amplitudes in a steel gun
housing.
[0034] In practice, exactly which direction the waves are reflected
(by the angle(s) on the surface(s) 56) should be carefully
considered to avoid creating a local stress problem on the gun
housing 32 wall. This is relevant to all of the examples described
above.
[0035] Thus, it will be appreciated that the shock mitigation
device 44 may mitigate shock by reflecting, absorbing, breaking-up,
scattering and/or dispersing the shock wave 42.
[0036] Referring additionally now to FIG. 6, yet another
configuration of the shock mitigating device 44 is representatively
illustrated. In this example, the device 44 includes a material 58
which produces a shock wave 60 that is oppositely directed relative
to the shock wave 42 produced by detonation of the explosive
components of the perforating gun 20, and is preferably timed to be
at least partially out of phase with the shock wave 42.
[0037] The material 58 could be, for example, an explosive sheet
material. The material 58 may be detonated in response to
detonation of any of the other explosive components (such as, the
detonating cord 36, perforating charge 38 or detonation booster 40,
etc.). Alternatively, the material 58 could be detonated a certain
amount of time before or after the other explosive components are
detonated.
[0038] Preferably, the shock wave 60 produced by detonation of the
material 58 at least partially "cancels" the shock wave 42, thereby
attenuating the shock wave. A sum of the shock waves 42, 60 is
preferably less than an amplitude of either of the shock waves.
[0039] A shock attenuator 46 may be used with the FIG. 6 example.
The shock attenuator 46 could include the materials 48, 50
described above, or in other examples, the shock attenuator could
include a dispersive media 62 (such as sand or glass beads, etc.)
to dissipate shock between a fluid interface and a structure (such
as a connector body 64). For example, the dispersive media could be
positioned between a steel plate and the connector body 64.
[0040] In any of the examples described above, the device 44 can be
configured so that it has a desired amount of shock mitigation. For
example, the amount of explosive material 58 or the timing of the
detonation in the FIG. 6 configuration can be changed as desired to
produce the shock wave 60 having certain characteristics. As
another example, the compliance, density, thickness, number and
resilience of the layers of materials 48, 50 in the configurations
of FIGS. 2 & 4 can be varied to produce corresponding
variations in shock attenuation.
[0041] This feature (the ability to vary the amount of internal
shock mitigation) can be used to "tune" the overall perforating
string 12, so that shock effects on the perforating string are
mitigated. Suitable methods of accomplishing this result are
described in International Application serial nos. PCT/US10/61104
(filed 17 Dec. 2010), PCT/US11/34690 (filed 30 Apr. 2011), and
PCT/US11/46955 (filed 8 Aug. 2011). The entire disclosures of these
prior applications are incorporated herein by this reference.
[0042] The examples of the shock mitigating device 44 described
above demonstrate that a wide variety of different configurations
are possible, while remaining within the scope of this disclosure.
Accordingly, the principles of this disclosure are not limited in
any manner to the details of the device 44 examples described above
or depicted in the drawings.
[0043] It may now be fully appreciated that this disclosure
provides several advancements to the art of mitigating shock
effects in subterranean wells. Various examples of shock mitigating
devices 44 described above can effectively prevent or at least
reduce transmission of shock to other components of the perforating
string 12.
[0044] In one aspect, the above disclosure provides to the art a
perforating gun 20. In one example, the perforating gun 20 can
include at least one explosive component (such as, the detonating
cord 36, perforating charge 38 or detonation booster 40, etc.), and
a shock mitigation device 44 including a shock reflector 52 which
indirectly reflects a shock wave 42 produced by detonation of the
explosive component.
[0045] The shock mitigation device 44 may close off an end of a gun
housing 32 containing the explosive component.
[0046] At least one surface 56 on the shock reflector 52 may
indirectly reflect the shock wave 42. The surface 56 can reflect
the shock wave 42 toward a gun housing 32 containing the explosive
component. The surface 56 may be generally conical-shaped.
[0047] The surface 56 may comprise multiple surfaces which reflect
the shock wave 42 as respective multiple reflected shock waves 54.
The reflected shock waves 54 may interfere with each other.
[0048] The shock mitigation device 44 can include a shock
attenuator 46 which attenuates the shock wave 42. The shock
reflector 52 may reflect the attenuated shock wave 42. The shock
attenuator 46 may comprise layers of resilient and non-resilient
materials 48, 50. Additional examples of resilient structures
include mechanical springs, etc. Additional examples of
non-resilient materials include crushable structures, such as
honeycomb or other celled structure, etc.
[0049] The shock attenuator 46 may comprises variations in acoustic
impedance. The shock attenuator 46 may comprise a dispersive media
62.
[0050] Also described above is a perforating gun 20 which, in one
example, can include a gun housing 32, at least one explosive
component (such as, the detonating cord 36, perforating charge 38
or detonation booster 40, etc.), and a shock mitigation device 44
in the gun housing 32. The shock mitigation device 44 may include a
shock attenuator 46 which attenuates a shock wave 42 produced by
detonation of the explosive component.
[0051] The shock mitigation device 44 may reflect the attenuated
shock wave 42, directly or indirectly. The shock mitigation device
44 may mitigate shock by reflecting, absorbing, breaking-up,
scattering and/or dispersing a shock wave 42.
[0052] This disclosure also describes a perforating gun 20 which,
in one example, includes a gun housing, at least one explosive
component (such as, the detonating cord 36, perforating charge 38
or detonation booster 40, etc.), and a shock mitigation device 44
in the gun housing 32, the shock mitigation device 44 including an
explosive material 58 which produces a first shock wave 60 that
interacts with a second shock wave 42 produced by detonation of the
explosive component.
[0053] The first shock wave 60 may at least partially counteract or
cancel the second shock wave 42. A sum of the first and second
shock waves 42, 60 can have an amplitude which is less than that of
each of the first and second shock waves 42, 60.
[0054] The explosive material 58 may detonate a predetermined
amount of time before or after the explosive component detonates.
The explosive component and the explosive material 58 may detonate
substantially simultaneously.
[0055] The first shock wave 60 may be produced in response to
impingement of the second shock wave 42 on the shock mitigation
device 44. The first shock wave 60 preferably propagates in a
direction opposite to a direction of propagation of the second
shock wave 42.
[0056] It is to be understood that the various embodiments of this
disclosure described herein may be utilized in various
orientations, such as inclined, inverted, horizontal, vertical,
etc., and in various configurations, without departing from the
principles of this disclosure. The embodiments are described merely
as examples of useful applications of the principles of the
disclosure, which is not limited to any specific details of these
embodiments.
[0057] In the above description of the representative examples,
directional terms (such as "above," "below," "upper," "lower,"
etc.) are used for convenience in referring to the accompanying
drawings. However, it should be clearly understood that the scope
of this disclosure is not limited to any particular directions
described herein.
[0058] Of course, a person skilled in the art would, upon a careful
consideration of the above description of representative
embodiments of the disclosure, readily appreciate that many
modifications, additions, substitutions, deletions, and other
changes may be made to the specific embodiments, and such changes
are contemplated by the principles of this disclosure. Accordingly,
the foregoing detailed description is to be clearly understood as
being given by way of illustration and example only, the spirit and
scope of the invention being limited solely by the appended claims
and their equivalents.
* * * * *