U.S. patent application number 11/860776 was filed with the patent office on 2009-03-26 for perforator charge with a case containing a reactive material.
This patent application is currently assigned to SCHLUMBERGER TECHNOLOGY CORPORATION. Invention is credited to Lawrence A. Behrmann, Richard T. Caminari.
Application Number | 20090078420 11/860776 |
Document ID | / |
Family ID | 40470409 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090078420 |
Kind Code |
A1 |
Caminari; Richard T. ; et
al. |
March 26, 2009 |
PERFORATOR CHARGE WITH A CASE CONTAINING A REACTIVE MATERIAL
Abstract
A perforator charge includes a case formed of a material blend
that includes a reactive material that is activated during
explosive detonation of the perforator charge. An explosive and a
liner are contained in the case, with the liner to collapse in
response to detonation of the explosive.
Inventors: |
Caminari; Richard T.;
(Rosharon, TX) ; Behrmann; Lawrence A.; (Houston,
TX) |
Correspondence
Address: |
SCHLUMBERGER RESERVOIR COMPLETIONS
14910 AIRLINE ROAD
ROSHARON
TX
77583
US
|
Assignee: |
SCHLUMBERGER TECHNOLOGY
CORPORATION
Sugar Land
TX
|
Family ID: |
40470409 |
Appl. No.: |
11/860776 |
Filed: |
September 25, 2007 |
Current U.S.
Class: |
166/297 ;
175/3.5; 175/4.5 |
Current CPC
Class: |
F42B 1/02 20130101; F42B
1/036 20130101; F42B 12/76 20130101; E21B 43/117 20130101 |
Class at
Publication: |
166/297 ;
175/3.5; 175/4.5 |
International
Class: |
E21B 29/02 20060101
E21B029/02 |
Claims
1. A perforator charge comprising: a case formed of a material
blend that includes a reactive material that is activated during
explosive detonation of the perforator charge; an explosive
contained in the case; and a liner contained ill the case, the
liner to collapse in response to detonation of the explosive.
2. The perforator charge of claim 1, wherein the reactive material
when activated during explosive detonation of the perforator charge
produces a pressure pulse in a wellbore interval.
3. The perforator charge of claim 2, wherein the reactive material
when activated produces a dynamic overbalance condition.
4. The perforator charge of claim 1, wherein the reactive material
is activated by at least one selected from the following: a
detonation gas, a wellbore fluid, and another reactive
material.
5. The perforator charge of claim 1, wherein the reactive material
comprises a powdered reactive material.
6. The perforator charge of claim 1, wherein the reactive material
is at least one material selected from the following: titanium, a
titanium alloy, titanium mixed with another metal, a titanium alloy
mixed with another metal, and nickel aluminum.
7. The perforator charge of claim 1, wherein the material blend of
the case further comprises a non-reactive material mixed with the
reactive material.
8. The perforator charge of claim 7, wherein the non-reactive
material is selected from the following: tungsten, copper, tin,
lead, and bismuth.
9. The perforator charge of claim 7, wherein the non-reactive
material provides enhanced density and strength for the case.
10. The perforator charge of claim 7, wherein the non-reactive
material and reactive material are compacted to form the case.
11. The perforator charge of claim 1, wherein the material blend
comprises a powdered material blend.
12. A perforating gun comprising: a carrier; and at least one
perforator charge mounted to the carrier, wherein the at least one
perforator charge comprises: a case formed of a material blend that
includes a reactive material that is activated in an explosive
detonation environment generated by the perforator charge; an
explosive contained in the case; and a liner contained in the case,
the liner to collapse in response to detonation of the
explosive.
13. The perforating gun of claim 12, wherein the material blend
further comprises a non-reactive material mixed with the reactive
material, the non-reactive material to provide density and green
strength.
14. The perforating gun of claim 12, wherein the at least one
perforator charge comprises at least one capsule perforator
charge.
15. The perforating gun of claim 12, wherein the at least one
perforator charge comprises at least one non-capsule perforator
charge.
16. The perforating gun of claim 12, wherein the carrier comprises
a carrier strip.
17. The perforating gun of claim 12, wherein the reactive material
is activated by at least one selected from the following:
detonation gases and a wellbore fluid.
18. The perforating gun of claim 12, wherein the reactive material
comprises at least one material selected from the following:
titanium, a titanium alloy, titanium mixed with another metal, a
titanium alloy mixed with another metal, and nickel aluminum.
19. A method for use in a wellbore, comprising: lowering a
perforating tool into the wellbore, wherein the perforating tool
comprises at least one perforator charge including a case that
contains an explosive, wherein the case is formed of a material
blend including a reactive material; and activating the at least
one perforator charge, wherein the reactive material of the at
least one perforator charge is activated during detonation of the
at least one perforator charge to create a corresponding pressure
pulse.
20. The method of claim 19, wherein the pressure pulse causes
generation of a dynamic overbalance condition in an interval of the
wellbore.
21. The method of claim 20, further comprising: performing at least
one of the following in presence of the dynamic overbalance
condition: fluid injection, transient overbalance generation, and
fracturing.
22. The method of claim 19, wherein the reactive material comprises
at least one material selected from the following: titanium, a
titanium alloy, titanium mixed with another metal, a titanium alloy
mixed with another metal, and nickel aluminum.
Description
TECHNICAL FIELD
[0001] The invention relates generally to a perforator charge
having a case including a reactive material.
BACKGROUND
[0002] To complete a well for purposes of producing fluids (such as
hydrocarbons) from a reservoir, or to inject fluids into the
reservoir, one or more zones in the well are perforated to allow
for fluid communication between the wellbore and the reservoir.
Normally, perforation is accomplished by lowering a perforating gun
string that has one or more perforating guns to the desired
intervals within the well. Activation of the one or more guns in
the perforating gun string creates openings in any surrounding
casing and extends perforations into the surrounding formation.
[0003] A perforating gun typically includes a gun carrier and a
number of shaped charges mounted to the gun carrier. The gun
carrier can be a sealed gun carrier that contains the shaped
charges and that protects the shaped charges from the external
wellbore environment. Alternatively, the gun carriers can be on a
strip carrier onto which capsule shaped charges are mounted. A
capsule shaped charge is a shaped charge whose internal components
are sealably protected against the wellbore environment.
[0004] The explosive nature of the formation of perforation tunnels
shatters sand grains of the formation. A layer of "shock damaged
region" having a permeability lower than that of the virgin
formation matrix may be formed around each perforation tunnel. The
process of forming perforation tunnels may also produce a tunnel
full of debris mixed with shaped charge debris. The extent of
damage and the amount of loose debris in the tunnels, may impair
the productivity of production wells or the injectivity of injector
wells.
[0005] Various approaches have been proposed to address damage and
the issue of debris associated with forming perforations using
perforating guns. However, it is desirable for additional solutions
that are not offered by conventional techniques.
SUMMARY
[0006] In general, according to an embodiment, a perforator charge
includes a case formed of a material blend that includes a reactive
material that is activated during explosive detonation of the
perforator charge. The reactive material of the case of the
perforator charge when activated can provide for various beneficial
effects, according to some embodiments. For example, a pressure
pulse may be created in a wellbore interval as a result of the
activation of the reactive material.
[0007] Other or alternative features will become apparent from the
following description, from the drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates an example tool string having a
perforating gun with perforator charges according to some
embodiments.
[0009] FIG. 2 illustrates a non-capsule perforator charge according
to an embodiment.
[0010] FIG. 3 illustrates a capsule perforator charge according to
another embodiment.
DETAILED DESCRIPTION
[0011] In the following description, numerous details are set forth
to provide an understanding of the present invention. However, it
will be understood by those skilled in the art that the present
invention may be practiced without these details and that numerous
variations or modifications from the described embodiments are
possible.
[0012] As used here, the terms "above" and "below"; "up" and
"down"; "upper" and "lower"; "upwardly" and "downwardly"; and other
like terms indicating relative positions above or below a given
point or element are used in this description to more clearly
describe some embodiments of the invention. However, when applied
to equipment and methods for use in wells that are deviated or
horizontal, such terms may refer to a left to right, right to left,
or diagonal relationship as appropriate.
[0013] FIG. 1 illustrates a tool string 102 that has been deployed
in a wellbore 104, where the tool string includes a perforating gun
106 that has a carrier 108 to which are mounted various perforator
charges 110 (e.g., shaped charges or other explosive devices that
form perforating jets) according to some embodiments. The carrier
108 can be an expendable carrier that is designed to shatter as a
result of detonation of the perforator charges 110. An example of
such an expendable carrier is a strip carrier, such as a carrier
formed of a metal strip. In a different implementation, instead of
mounting the perforator charges 110 on a strip carrier, the carrier
can be a seated housing that has an inner chamber in which the
perforator charges are located, with the chamber being sealed
against external wellbore fluids in the wellbore 104.
[0014] As depicted in FIG. 1, when the perforator charges 110 are
mounted to the carrier strip 108 such that the perforator charges
110 are exposed to wellbore fluids, the perforator charges 110 are
capsule perforator charges that have a capsule to provide a fluid
seal to protect internal components of the perforator charges 110
against the wellbore fluids. Alternatively, if the perforator
charges 110 are provided in a sealed chamber of a carrier housing,
in a different implementation, then the perforator charges can be
non-capsule perforator charges.
[0015] The perforator charges 110 in the example of FIG. 1 are
ballistically connected to a detonating cord 112. The detonating
cord 112 is connected to a firing head 114. When activated, the
firing head 114 initiates the detonating cord 112, which in turn
causes detonation of the perforator charges 110.
[0016] In a different implementation, the detonating cord 112 can
be replaced with one or more electrical wires connecting the firing
head 114 to the perforator charges. Electrical signal(s) can be
sent by the firing head 114 over the one or more electrical wires
to activate the perforator charges. For example, the perforator
charges can be associated with electrically-activated initiators
(e.g., electrical foil initiators or EFIs), which when activated by
an electrical signal causes initiation of a detonator or explosive
to detonate the corresponding perforator charge.
[0017] The perforating gun 106 is carried by a carrier line 116,
which can be a wireline, slickline, coiled tubing, production
tubing, and so forth. In accordance with some embodiments, each
perforator charge 110 has an outer case that is formed of a
material blend that includes a reactive material. A reactive
material refers to a material that reacts with detonation gases,
wellbore fluids, and/or with another reactive material during
explosive detonation of the perforator charge. Reaction of the
reactive material in the outer case of the perforator charge can
produce a pressure pulse that can last for some amount of time
longer (e.g., one or two orders of magnitude longer) than the
explosive detonation of the perforator charge.
[0018] In some embodiments, the material blend of the case of the
perforator charge can be a powdered material that includes the
reactive material as well as a non-reactive material that provides
for enhanced density and strength of the case. In a different
embodiment, the material blend of the outer case can be a solid,
rather than a powdered, material blend.
[0019] The pressure pulse generated as a result of activation of
the reactive material during perforator charge detonation can
produce a dynamic overbalance condition in a particular wellbore
interval (the interval in which the perforator charge or
perforating gun is located), which is a pressure condition in which
the particular wellbore interval achieves a higher pressure than
the pressure of a surrounding reservoir (or at least the
near-wellbore region of the surrounding reservoir). Creating a
dynamic overbalance condition in a wellbore interval has several
potential applications, including injecting one or more target
fluids into perforation tunnels, producing a transient overbalance
condition, fracturing perforation tunnels, and so forth.
[0020] In some examples, the one or more target fluids that can be
injected into perforation tunnels include a treating fluid such as
a consolidation fluid that can be used to strengthen perforation
tunnels and near-wellbore regions of the reservoir to prevent
formation movement or movement of fine particles. One example type
of consolidation fluid includes an epoxy fluid that is embedded
with micro-capsules, where the micro-capsules have inner cavities
that contain a hardener or catalyst fluid. A different type of
treating fluid can be a post-wash fluid. Another type of treating
fluid can be acid, such as HCl to treat a carbonate reservoir.
Acidizing helps remove or reduce perforation damage. Yet another
type of treating fluid can be proppant-laden fracturing fluid,
where the proppant includes particles mixed with fracturing fluid,
which can be used in a fracturing operation to hold fractures
open.
[0021] FIG. 2 shows an example perforator charge 110 that has an
outer case 200. The outer case 200 defines an inner chamber 202 to
receive a main explosive 204. Also, a liner 206 is provided inside
the outer case 202, where the liner 206 generally has a generally
conical shape. The conical shape of the liner 206 provides for a
deeper perforation hole. Alternatively, the liner 206 can have a
different shape, such as a general bowl shape, which would allow
for creation of larger holes. The main explosive 204 is provided
between the liner 206 and the inside of the outer case 200.
[0022] In some embodiments, the outer case 200 can be formed of a
powered material, using a compaction technique, where the powdered
material includes both a non-reactive material for density and
green strength (which refers to the ability of the case to undergo
handling without distortion), and a reactive material that is
activated by detonation gases, wellbore fluids, and/or with another
reactive material during detonation of the perforator charge.
[0023] The compaction technique used to form the outer case 200
involves mixing the non-reactive and reactive material and applying
compaction to the mixture to form the case 200. In other
implementations, other manufacturing techniques can be used to make
the outer case 200, such as an injection molding technique or other
technique.
[0024] A reactive material can include just a single material or a
combination of multiple reactive materials. Examples of the
reactive material that can be used in the case 200 include titanium
(Ti), nickel-aluminum (Ni--Al), a titanium alloy (e.g., titanium
iron, titanium silicon, titanium nickel, titanium aluminum,
titanium copper, etc.), a titanium powder mixed with other metal
powder (e.g., magnesium, tungsten, copper, lead, tin, zinc, gold,
silver, steel, tantalum, etc.), a titanium alloy powder mixed with
other metal powder, and any other reactive materials. Examples of
non-reactive materials include tungsten, copper, lead, bismuth,
tin, and so forth.
[0025] To increase the green strength of the powdered material case
200, a high-temperature epoxy coating can be applied to the
external surface of the case 200, or alternatively, the case 200
can be impregnated with a high-temperature epoxy. The epoxy can
also contain a fuel and/or an oxidizer in some implementations to
aid in disintegration of the case 200.
[0026] As further depicted in FIG. 2, an opening 208 at the rear of
the case 200 allows for an explosive material portion 210 to be
provided, where the explosive material portion 210 is ballistically
coupled to the detonating cord 112 to allow for initiation in the
detonating cord 112 to cause the explosive material portion 210 to
detonate, which in turn causes the main explosive 204 to detonate.
Detonation of the main explosive 204 causes the liner 206 to
collapse such that a perforating jet is formed, where the
perforating jet extends away from the perforator charge 110. The
perforating jet is directed towards the structure (e.g., casing
and/or surrounding formation) in which a corresponding perforation
tunnel is to be formed.
[0027] During detonation of the main explosive 204, the reactive
material inside the outer case 200 reacts with the detonation
environment such that the reactive material is activated to
generate heat or gas that increases pressure. As a result, a
pressure pulse can be produced from reaction or activation of the
reactive material, where the pressure pulse lasts longer than the
explosive detonation of the perforator charge 110.
[0028] As noted above, the pressure pulse produces a dynamic
overbalance condition in a wellbore interval, where the dynamic
overbalance condition can be used for various purposes, including
fluid injection, transient overbalance creation, and fracturing, as
examples.
[0029] FIG. 3 shows an alternative embodiment of a perforator
charge, identified as 110A. The perforator charge 110A is identical
in construction with the perforator charge 110 of FIG. 2, except
that a cap 300 is also provided in the perforator charge 110A to
sealably engage with the outer case 200, where the cap 300 allows
for the internal components of the perforator charge (liner and
explosive material to be protected from the external wellbore
environment.
[0030] Effectively, the cap 300 and outer case 200 form a capsule
that sealably defines a sealed inner chamber containing the
internal components of the perforator charge. The perforator charge
110A is a capsule perforator charge, whereas the perforator charge
110 of FIG. 2 is a non-capsule perforator charge.
[0031] A further benefit of using an outer casing (particularly one
formed of a powdered material) that includes a reactive material is
that activation of the reactive material helps to further reduce
debris associated with the perforator charge. Activation of the
reactive material helps to further disintegrate the outer
casing.
[0032] While the invention has been disclosed with respect to a
limited number of embodiments, those skilled in the art, having the
benefit of this disclosure, will appreciate numerous modifications
and variations therefrom. It is intended that the appended claims
cover such modifications and variations as fall within the true
spirit and scope of the invention.
* * * * *