U.S. patent application number 13/231494 was filed with the patent office on 2013-03-14 for active waveshaper for deep penetrating oil-field charges.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. The applicant listed for this patent is David Betancourt, William B. Harvey. Invention is credited to David Betancourt, William B. Harvey.
Application Number | 20130061771 13/231494 |
Document ID | / |
Family ID | 47828658 |
Filed Date | 2013-03-14 |
United States Patent
Application |
20130061771 |
Kind Code |
A1 |
Betancourt; David ; et
al. |
March 14, 2013 |
ACTIVE WAVESHAPER FOR DEEP PENETRATING OIL-FIELD CHARGES
Abstract
A shaped charge having a liner, a shaped charge case, high
explosive between the ilner and the case, and an active wave
shaping element that is made of an energetic material that reacts
at a rate different from the high explosive. The wave shaping
element is disposed in the high explosive between an apex of the
liner and base of the shaped charge case. Example materials of the
wave shaping element include HMX, RDX, PBX types, PETN, HNS, TATB,
and combinations thereof.
Inventors: |
Betancourt; David; (Cypress,
TX) ; Harvey; William B.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Betancourt; David
Harvey; William B. |
Cypress
Houston |
TX
TX |
US
US |
|
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
47828658 |
Appl. No.: |
13/231494 |
Filed: |
September 13, 2011 |
Current U.S.
Class: |
102/307 ;
166/297; 89/1.15 |
Current CPC
Class: |
F42B 3/08 20130101; E21B
43/117 20130101; F42B 1/02 20130101 |
Class at
Publication: |
102/307 ;
89/1.15; 166/297 |
International
Class: |
F42B 3/08 20060101
F42B003/08; E21B 43/117 20060101 E21B043/117; E21B 43/11 20060101
E21B043/11; F42B 1/028 20060101 F42B001/028 |
Claims
1. A shaped charge for use in perforating a wellbore comprising: a
shaped charge case configured for use in a perforating gun; a high
explosive in the shaped charge case having a speed of detonation; a
liner adjacent the high explosive in the shaped charge case: a wave
shaping element comprising an energetic material having a speed of
reaction less than the speed of detonation and disposed in a path,
of a detonation wave that is between a location of initiation of
the detonation wave and the liner, so that when the detonation wave
is generated by detonation of the high explosive, the detonation
wave Is shaped by the wave shaping element.
2. The shaped charge of claim 1, wherein the detonation wave
upstream of the wave shaping element, is more divergent than when
the detonation wave is downstream, of the wave shaping element.
3. The shaped charge of claim 1, wherein the wave shaping element
comprises a material selected from the list consisting of HMX, RDX,
PBX types, PETN, HNS, TATB, and combinations thereof.
4. The shaped charge of claim 1, further comprising a cavity formed
through an end of the shaped charge case, wherein the high
explosive and liner is disposed in the cavity.
5. The shaped charge of claim 4, further comprising a booster
charge in an end of the shaped charge case opposite the end having
the cavity, wherein the liner has a generally conical shape with a
rounded apex facing the booster charge, and wherein the wave
shaping element is disposed in a space between the apex and the
booster charge.
6. The shaped charge of claim 1, wherein the wave shaping element
has a lenticular cross section and is generally coaxial with an
axis of the shaped charge.
7. The shaped charge of claim 1, wherein the high explosive
comprises a material selected from the list consisting of HMX, RDX,
PBX types, PETN, HNS, TATB, and combinations thereof.
8. A method of perforating a wellbore comprising: a. providing a
shaped charge having a shaped charge liner, high explosive adjacent
the shaped charge liner, and a wave shaping element in the high
explosive that comprises an energetic material that has a rate of
reaction, that differs from a rate of reaction of the high
explosive; b. disposing the shaped charge in a wellbore; and c.
initiating detonation of tie high explosive to form a detonation
wave for collapsing the shaped charge liner.
9. The method of claim 8, wherein the detonation wave downstream of
the wave shaping element diverges less than when upstream of the
wave shaping element.
10. The method of claim 8, wherein the step of initiating
detonation of the high explosive comprises generating a detonation
wave in a detonating cord, and transferring the detonation wave
from the detonating cord to the high explosive.
11. The method of claim 8, further comprising disposing the high
explosive, shaped charge liner, and wave shaping element in a
shaped charge ease to define a shaped charge.
12. The method of claim 8, further comprising repeating step (a)
multiple times to provide multiple shaped charges, disposing the
multiple shaped charges into a perforating gun having a detonation
cord.
13. A perforating system comprising: a cylindrical perforating gun
body; shaped charges in the gun body comprising a shaped charge
case having a cavity with, walls and a bottom, a shaped charge
liner in the cavity, high explosive between the shaped charge liner
and the walls and bottom of the cavity, and a wave shaping element
in the cavity between an apex of the shaped charge liner and bottom
of the cavity and that comprises a material that reacts at a rate
different from that at which the high explosive reacts.
14. The perforating system of claim 13, wherein the material of the
wave shaping element comprises HMX, RDX, PBX types, PETN, HNS,
TATB, and combinations thereof.
15. The perforating system of claim 13, further comprising a
detonating cord extending lengthwise through the gun body and
disposed adjacent an end of the shaped charge case having a booster
charge.
16. The perforating system of claim 13, wherein the wave shaping
element is coated with a fluorocarbon based polymer.
17. The perforating system of claim 13, wherein the apex extends
into the wave shaping element.
18. The perforating system of claim 13, wherein the wave shaping
element is spaced apart from the apex.
Description
BACKGROUND
[0001] 1. Field of Invention
[0002] The present invention relates to ballistics devices used in
oil and gas production. More specifically, the present invention
relates to a shaped charge having a wave shaping element having an
energetic material.
[0003] 2. Description of Prior Art
[0004] Hydrocarbon producing wellbores typically intersect multiple
zones within subterranean formations. Perforating systems are often
used for perforating hydraulic passages through walls of the
wellbores into one or more of the zones thereby hydraulically
communicating the perforated zones to the wellbore. Wellbores are
usually completed by coaxially inserting a pipe or casing into the
wellbore where it is then cemented in place by pumping cement into
the annular space between the wellbore and the casing. The cement
forms a flow barrier hydraulically isolating the zones from one
another in the annular space.
[0005] The perforating systems typically include a gun body that
houses a number of shaped charges. FIG. 1 illustrates a prior art
example of a shaped charge 10. Each shaped charge 10 generally
include a housing 12, a liner 14, and high explosive 16.
Traditionally some of the high explosives that have been used are
HMX, RDX, PBX types, and PETN. The housing 12 usually has an open
end and a cylindrically shaped open space or cavity 17 therein in
which the explosive 16 and liner 14 are provided. Liners 14 are
typically metal particles that are molded into thin walled, hollow,
and conically shaped members having a rounded apex and open at the
base. The liner 14 is disposed into the open space 17 of the
housing 12, apex side first, with the high explosive 16 between the
liner 14 and housing 12. Detonating the high explosive 16 forms
detonation waves 18 that transmit through the high explosive 16 and
collapse and invert the liner 14, converting the liner 14 into an
elongated metal jet that is ejected from the shaped charge housing
12. The jet exits the gun body and penetrates the well casing and
the surrounding geologic formations. The jet properties depend on
the shape of the charge case 12 and liner 14, released energy, as
well as the mass and composition of the liner 14. Generally the
high explosive 16 is detonated by exploding a booster charge 20
shown adjacent the high explosive 16, where the booster charge
explosion is initiated by an associated detonation cord 22.
[0006] Various efforts have been made to modify the performance of
shaped charges. Barriers and voids have been placed within the
explosive material to modify the detonation wave shape collapsing
the liner. Wave shaping techniques have involved positioning the
high explosive between the detonator cord and the liner. For
example, a spoiler was positioned within the liner cavity to modify
the perforating jet shape. Other efforts have been made to modify
perforating jet performance by changing the liner shape, thickness,
or configuration.
SUMMARY OF THE INVENTION
[0007] The present disclosure describes examples of a shaped charge
and methods of perforating a wellbore. In one example embodiment,
disclosed herein is a shaped charge that includes a high explosive
having a speed of detonation and a liner adjacent the high
explosive. A wave shaping element is included with the shaped
charge that is made of an energetic material, where the energetic
material has a speed of reaction less than the speed of detonation
of the high explosive. The wave shaping element is disposed in a
path of a detonation wave, which is between a location of
initiation of the detonation wave and the liner. Thus when the
detonation wave is generated by detonation of the high explosive
and propagates through the wave shaping element, the detonation
wave is shaped by the wave shaping element. In one example
embodiment, the detonation wave upstream of the wave shaping
element is more divergent than when the detonation wave is
downstream of the wave shaping element. Optionally, the wave
shaping element is made up of HMX, RDX, PBX types, PETN, HNS, TATB,
or combinations thereof. A shaped charge case may be included with
the shaped charge, where the shaped charge case has a cavity formed
through one of its ends for placing the high explosive and liner.
Also, a booster charge may optionally be disposed in an end of the
shaped charge case opposite the end having the cavity. In an
example, the liner has a generally conical shape with a rounded
apex facing the booster charge, and wherein the wave shaping
element is disposed in a space between the apex and the booster
charge. The wave shaping element may have a lenticular cross
section and can be generally coaxial with an axis of the shaped
charge. The high explosive may be made up of a material such as
HMX, RDX, PBX types, PETN, HNS, TATB, or combinations thereof.
[0008] Also included herein is a method of perforating a wellbore.
In one example the method involves providing a shaped charge having
a shaped charge liner and with high explosive adjacent the shaped
charge liner. The method also includes providing a wave shaping
element in the high explosive. The wave shaping element of this
example is made up of an energetic material whose rate of reaction
differs from the rate the high explosive reacts. The shaped charge
is then disposed in a wellbore and is initiated to form a
detonation wave for collapsing the shaped charge liner. Optionally,
the wave shaping element diverges less downstream than when
upstream of the wave shaping element. Alternatively, initiating
detonation of the high explosive can include generating a
detonation wave in a detonating cord and transferring the
detonation wave from the detonating cord to the high explosive. The
method can further optionally include disposing the high explosive,
shaped charge liner, and wave shaping element in a shaped charge
case to define a shaped charge. The steps of providing can be
repeated multiple times to obtain multiple shaped charges that can
be disposed into a perforating gun having a detonation cord.
[0009] A perforating system is also described herein that includes
a cylindrical perforating gun body having shaped charges. The
shaped charges include a shaped charge case having a cavity with
walls and a bottom, a shaped charge liner in the cavity, high
explosive between the shaped charge liner and the walls and bottom
of the cavity, and a wave shaping element in the cavity between an
apex of the shaped charge liner and bottom of the cavity. The wave
shaping element includes a material that reacts at a rate different
from that at which the high explosive reacts. In one optional
embodiment, the material of the wave shaping element includes HMX,
RDX, PBX types, PETN, HNS, TATB, or combinations thereof. Further
optionally included is a detonating cord extending lengthwise
through the gun body and disposed adjacent an end of the shaped
charge case having a booster charge. In one example, the wave
shaping element is coated with a fluorocarbon based polymer. The
apex may optionally extend into the wave shaping element.
Alternatively, the wave shaping element is spaced apart from the
apex.
BRIEF DESCRIPTION OF DRAWINGS
[0010] Some of the features and benefits of the present invention
having been stated, others will become apparent as the description
proceeds when taken in conjunction with the accompanying drawings,
in which:
[0011] FIG. 1 is a side sectional view of a prior art example of a
shaped charge.
[0012] FIG. 2 is a side sectional view of an example embodiment of
a shaped charge in accordance with the present invention.
[0013] FIG. 3 is a partial side sectional view of an example
embodiment of perforating a wellbore using the shaped charge of
FIG. 2 in accordance with the present invention.
[0014] FIGS. 4A and 4B are side sectional views of example
embodiments of the shaped charge of FIG. 2 in accordance with the
present invention.
[0015] While the invention will be described in connection with the
preferred embodiments, it will be understood that it is not
intended to limit the invention to that embodiment. On the
contrary, it is intended to cover all alternatives, modifications,
and equivalents, as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILED DESCRIPTION OF INVENTION
[0016] The method and system of the present disclosure will now be
described more fully hereinafter with reference to the accompanying
drawings in which embodiments are shown. The method and system of
the present disclosure may be 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 its
scope to those skilled in the art. Like numbers refer to like
elements throughout.
[0017] It is to be further understood that the scope of the present
disclosure is not limited to the exact details of construction,
operation, exact materials, or embodiments shown and described, as
modifications and equivalents will be apparent to one skilled in
the art. In the drawings and specification, there have been
disclosed illustrative embodiments and, although specific terms are
employed, they are used in a generic and descriptive sense only and
not for the purpose of limitation. Accordingly, the improvements
herein described are therefore to be limited only by the scope of
the appended claims.
[0018] An example embodiment of a shaped charge 30 is shown in a
side sectional view in FIG. 2 that is made up of a shaped charge
case 32 having a cavity 33 formed through one end of the shaped
charge case 32. A conically-shaped liner 34 is shown inserted
within the cavity 33 that has a rounded apex directed towards a
base or bottom of the cavity 33. In the example of FIG. 2, the
liner 34 is substantially coaxial with an axis Ax of the shaped
charge 30. High explosive 36 is shown disposed between the liner 34
and walls and base of the cavity 33. Optionally included with the
high explosive 36 is a binder 37 that in one example embodiment can
be used for shaping the high explosive 36 within the shaped charge
case 32. The binder 37 may be a wax-based material or may be a
polychlorotrifluoroethylene, as well as other fluorocarbon-based
polymers.
[0019] Provided in the space between the apex of the liner 34 and
base of the cavity 33 is a wave shaping element 38. The wave
shaping element 38 of FIG. 2 has a generally lenticular cross
section having a major axis and a minor axis; wherein the minor
axis is generally coaxial with the axis Ax. In the example
embodiment of FIG. 2, the wave shaping element 38 includes a
coating 39 on its outer surface that in an example embodiment
includes a fluorocarbon-based polymer. The material making up the
wave shaping element 38 is energetic and having a rate of reaction
that differs from a rate of reaction of the high explosive 36.
Example materials for the wave shaping element 38 include HMX, RDX,
PBX types, PETN, HNS, TATB, and combinations thereof.
[0020] The shaped charge 30 of FIG. 2 further includes a booster
charge 40 shown provided in the bottom end of the shaped charge
case 32 and opposite the opening to the cavity 33. The booster
charge 40 includes a material that reacts more readily than the
high explosive 36. In one example embodiment the booster charge 40
is made up of a primary explosive and the high explosive 36 is made
up of a secondary explosive; wherein the primary explosive
detonates in response to a stimulus that would generally not
initiate detonation within the high explosive 36. Detonation of the
booster charge 40 though is capable of detonating the high
explosive 36.
[0021] A detonating cord 42 is shown set adjacent an end of the
booster charge 40 opposite the high explosive 36 and is provided
for initiating explosion or detonation within the booster charge
40. An example detonation wave 44 is illustrated within FIG. 2,
that in an example depict how detonation of the high explosive 36
can initiate from the booster charge 40, propagate along a path
running substantially parallel with the axis Ax, and ultimately
exit the shaped charge 30.
[0022] In an example embodiment, the presence of the wave shaping
element 38, as illustrated, alters the shape of the detonation wave
44 to a less diverging configuration. For example, the detonation
wave 44 upstream of the wave shaping element 38 is shown having a
radius that is less than a radius of the detonation wave 44
downstream of the wave shaping element 38. As discussed above, the
material of the wave shaping element 38 as disclosed herein is
energetic and explodes and/or detonates in response to detonation
of the high explosive 36. Detonation or explosion of the wave
shaping element 38 may be caused directly by the detonation wave
44. An advantage of a wave shaping element 38 that is active,
rather than passive is that attenuation of the detonation wave 44
through the active wave shaping element 38 is less than attenuation
through wave shaping elements formed from a nonreactive
material.
[0023] In an example embodiment, the wave shaping element 38
provides a lensing effect of reshaping the configuration of the
detonation wave 44. Although the detonation wave 44 propagating
downstream of the wave shaping element 38 is shown as having a
non-linear wave front, the wave front may optionally be
substantially linear and oriented generally perpendicular with the
direction of the axis Ax. Other configurations exist wherein the
detonation wave 44 has a wave front inverted from that of FIG. 2;
that is having a radius with an origin on a side of the detonation
wave 44 opposite that of the booster charge 40.
[0024] A faster collapsing liner 34 and thus deeper penetration is
one advantage of shaping the wave front of the detonation wave 44.
An advantage of combining the binder 37 with the high explosive 36
is that the high explosive 36 may be conformed into a desired
shape, and having a precise contour and dimensions. The binder 37
also increases repeatability of forming high explosive 36 into a
desired shape with precise dimensions and contour. Increased
precision allows for more symmetrically shaped high explosives that
in turn form more coherent and straighter jets that those generated
by less symmetrically formed high explosives. Because incoherency
of jet formation is exacerbated with increasing jet velocity,
embodiments combining the wave shaping element 38 with precisely
configured high explosive 36 substantially symmetric about the axis
Ax, provides for the higher velocity detonation wave 44 and jet
formed by the inverting liner 34 that is on and not offset from the
axis Ax.
[0025] Referring now to FIG. 3, an example embodiment of a
perforating system 45 is shown in a partial sectional view and
disposed within a borehole 46. In the example of FIG. 3, the shaped
charge 30 of FIG. 2 is provided with an elongated and substantially
cylindrical perforating gun 48 that is attached to other
perforating guns to define a perforating string. Shaped charges 30
are provided in the perforating guns 48. An example of the step of
perforating is shown in FIG. 3 wherein jets 49 are shown being
discharged from the shaped charges 30 within the perforating guns
48 and that form perforations 50 into a formation 52 that surrounds
the borehole 46. An example advantage of using the wave shaping
element 38 is that the perforations 50 may penetrate deeper and
straighter within the formation 52 than shaped charges not having a
wave shaping element. Moreover, the wave shaping element 38 as
disclosed herein may form perforations 50 that are deeper than
those formed by other shaped charges having a passive wave shaping
element.
[0026] Further in the example of FIG. 3, a wireline 54 is included
that can be used for deploying the string of perforating guns 48
within the borehole 46. The wireline 54 may also be used for
directing a signal to the perforating guns 48 that causes
detonation of the shaped charges 30. The wireline 54 is shown
passing through a wellhead assembly 56 that is mounted on an upper
end of the bore hole 46. Control of the wireline 54, and optionally
the signals through the wire line 54, is maintained via a surface
truck 58 shown set on the surface and above the bore hole opening.
In the perforating system 45, an initiator 60 is shown on an upper
end that couples with the detonating cord 42, that as discussed
above, initiates explosion or detonation within the booster charge
40 (FIG. 2).
[0027] FIGS. 4A and 4B provide alternate embodiments of the shaped
charge 30 of FIG. 2. Specifically as illustrated in FIG. 4A, a
shaped charge 30A is provided wherein the wave shaping element 38
is not intersected by the apex of the liner 34, instead the wave
shaping element 38 is positioned to be in contact with and adjacent
the apex of the liner 34. In another optional embodiment, a shaped
charge 30B is shown in sectional view in FIG. 4B wherein the wave
shaping element 38 is spaced rearward of the apex of the liner 34,
thereby leaving a space between the wave shaping element 38 and
apex of the liner 34. In both embodiments of FIGS. 4A and 4B, the
resulting detonation waves 44 take on a less diverging
configuration downstream of the wave shaping element 38 than
upstream so that the collapsing of the liner 34 occurs at a rate
that is faster than that would occur without the strategically
located wave shaping element 38. As such, higher energy jets may be
produced for providing deeper penetrations within
hydrocarbon-producing formations.
[0028] The present invention described herein, therefore, is well
adapted to carry out the objects and attain the ends and advantages
mentioned, as well as others inherent therein. While a presently
preferred embodiment of the invention has been given for purposes
of disclosure, numerous changes exist in the details of procedures
for accomplishing the desired results. For example, coiled tubing
may be used in place of the wireline. These and other similar
modifications will readily suggest themselves to those skilled in
the art, and are intended to be encompassed within the spirit of
the present invention disclosed herein and the scope of the
appended claims.
* * * * *