U.S. patent application number 17/330699 was filed with the patent office on 2022-01-20 for multi-layer loading tube for perforating gun.
The applicant listed for this patent is GEODYNAMICS, INC.. Invention is credited to Jim ROLLINS, Wenbo YANG.
Application Number | 20220018224 17/330699 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-20 |
United States Patent
Application |
20220018224 |
Kind Code |
A1 |
YANG; Wenbo ; et
al. |
January 20, 2022 |
MULTI-LAYER LOADING TUBE FOR PERFORATING GUN
Abstract
A perforating gun for perforating a casing of a well includes
one or more shaped charges configured to perforate the casing; a
loading tube configured to hold the one or more shaped charges; a
housing having a cylindrical shape and configured to receive inside
the loading tube and the one or more shaped charges; and a
protective tube located in an annulus formed between the housing
and the loading tube.
Inventors: |
YANG; Wenbo; (Kennedale,
TX) ; ROLLINS; Jim; (Lipan, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GEODYNAMICS, INC. |
Millsap |
TX |
US |
|
|
Appl. No.: |
17/330699 |
Filed: |
May 26, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63053778 |
Jul 20, 2020 |
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International
Class: |
E21B 43/117 20060101
E21B043/117; E21B 43/119 20060101 E21B043/119; E21B 43/1185
20060101 E21B043/1185 |
Claims
1. A perforating gun for perforating a casing of a well, the
perforating gun comprising: one or more shaped charges configured
to perforate the casing; a loading tube configured to hold the one
or more shaped charges; a housing having a cylindrical shape and
configured to receive inside the loading tube and the one or more
shaped charges; and a protective tube located in an annulus formed
between the housing and the loading tube.
2. The perforating gun of claim 1, wherein the loading tube, the
protective tube, and the housing are concentric to each other.
3. The perforating gun of claim 1, wherein the protective tube
fully encircles the loading tube.
4. The perforating gun of claim 1, wherein the protective tube
includes plural discrete sections, each section fully enclosing a
corresponding portion of the loading tube.
5. The perforating gun of claim 1, wherein the protective tube has
plural holes, each hole being configured to receive a corresponding
shaped charge of the one or more shaped charges.
6. The perforating gun of claim 1, wherein the housing has plural
scallops, and the protective tube has plural holes, and each hole
is radially aligned with a corresponding scallop.
7. The perforating gun of claim 1, wherein the protective tube is
located so that there is a first annulus between the loading tube
and the protective tube and a second annulus between the protective
tube and the housing.
8. The perforating gun of claim 1, further comprising: plural legs
that extend throughout an entire wall of the protective tube to
contact the loading tube, wherein the plural legs maintain the
protective tube centered around the loading tube.
9. The perforating gun of claim 1, further comprising: end plates
that attach to the loading tube, the end plates having one or more
slots so that tabs of the protective tube enter the one or more
slots and the protective tube is maintained around the loading tube
without touching the loading tube.
10. The perforating gun of claim 1, wherein only the one or more
shaped charges holds the protective tube around the loading
tube.
11. The perforating gun of claim 1, wherein the protective tube
includes two or more concentric tubes having different thicknesses
or made of different materials.
12. The perforating gun of claim 1, further comprising: a detonator
cord that connects to the one or more shaped charges; and a
detonator configured to ignite the detonation cord, wherein the
detonator is located inside the housing but outside the protective
tube.
13. The perforating gun of claim 1, wherein the protective tube is
configured to not interfere with a melted jet produced by the one
or more shaped charges.
14. A perforating gun for perforating a casing of a well, the
perforating gun comprising: one or more shaped charges configured
to perforate the casing; a loading tube configured to hold the one
or more shaped charges; a protective tube located around the
loading tube and configured to receive the one or more shaped
charges in corresponding holes; and a housing located around the
protective tube.
15. The perforating gun of claim 14, wherein the loading tube, the
protective tube, and the housing are concentric to each other.
16. The perforating gun of claim 14, wherein the protective tube is
located so that there is a first annulus between the loading tube
and the protective tube and a second annulus between the protective
tube and the housing.
17. The perforating gun of claim 14, further comprising: plural
legs that extend throughout an entire wall of the protective tube
to contact the loading tube, wherein the plural legs maintain the
protective tube centered around and radially distanced from the
loading tube.
18. The perforating gun of claim 14, further comprising: end plates
that attach to the loading tube, the end plates having one or more
slots so that tabs of the protective tube enter the one or more
slots and the protective tube is maintained around the loading tube
without touching the loading tube.
19. A method for protecting a housing of a perforating gun from
excessive damage, the method comprising: placing one or more shaped
charges into a loading tube of a perforating gun; covering the
loading tube with a protective tube; and loading the loading tube
with the protective tube into a housing of the perforating gun,
wherein the protective tube is located in an annulus formed between
the loading tube and the housing.
20. The method of claim 19, further comprising: centering the
protective tube around the loading tube.
Description
BACKGROUND
Technical Field
[0001] Embodiments of the subject matter disclosed herein generally
relate to a perforating gun for making perforations into a casing
of a well, and more specifically, to a multi-layer loading tube
that holds the shaped charges and prevents damage to a housing of
the perforating gun.
Discussion of the Background
[0002] In the oil and gas field, once a well is drilled to a
desired depth H relative to the surface, and the casing protecting
the wellbore has been installed and cemented in place, it is time
to connect the wellbore to the subterranean formation to extract
the oil and/or gas. This process of connecting the wellbore to the
subterranean formation may include a step of plugging a previously
fractured stage of the well with a plug, a step of perforating a
portion of the casing, which corresponds to a new stage, with a
perforating gun string such that various channels are formed to
connect the subterranean formation to the inside of the casing, a
step of removing the perforating gun string, and a step of
fracturing the various channels of the new stage. These steps are
repeated until all the stages of the formation are fractured.
[0003] During the perforating step for a given stage, one or more
perforating guns of the perforating gun string are used to create
perforation clusters in the multistage well. Clusters are typically
spaced along the length of a stage (a portion of the casing that is
separated with plugs from the other portions of the casing), and
each cluster comprises multiple perforations (or holes). Each
cluster is intended to function as a point of contact between the
wellbore and the formation. Each perforation is made by a
corresponding shaped charge, which is located inside the housing of
the perforating gun. The shaped charge includes an explosive
material which when ignited, melts a lining of the shaped charge
and generates a travelling melted jet. The travelling melted jet is
projected outward from the shaped charge, to make a perforation
into the housing of the perforating gun and then a perforation into
the casing of the well, to establish the fluid communication
between the oil formation outside the well and the bore of the
casing.
[0004] After each stage is perforated, a slurry of proppant (sand)
and liquid (water) is pumped into the stage at high rates and then,
through the perforation holes, into the formation, with the intent
of hydraulically fracturing the formation to increase the contact
area between that stage and the formation. A typical design goal is
for each of the clusters to take a proportional share of the slurry
volume, and to generate effective fractures, or contact points,
with the formation, so that the well produces a consistent amount
of oil cluster to cluster and stage to stage.
[0005] However, due to the improved efficiency of the shaped
charges and their increased firing angle, the traveling melted jet
may severely damage the housing of the perforating gun, in addition
to the intended perforation, so that the housing may split or
become so deformed that would inhibit the ability to move the used
up perforating gun within the casing. In other words, as shown in
FIG. 1, a perforating gun string 110, that includes first and
second perforating guns 112 and 114, is lowered into a well 116,
with a wireline 118. The wireline 118 is connected to a derrick
120, that is controlled by a controller 122, for example, a
computing device. The derrick 120 and the controller 122 are
located at the surface 124. The first and second perforating guns
112 and 114 sit on the casing 130 of the well 116 and each
perforating gun may include plural shaped charges 112A and 114A,
respectively. While the shaped charges 112A of the first
perforating gun 112 have not yet been detonated, the shaped charges
114A of the second perforating gun 114 have been detonated. In this
regard, it is noted that the housing 115 of the second perforating
gun 114 has various holes, which correspond to each of the fired
shaped charges. Further, FIG. 1 shows that the margins 132 of a
given hole formed in the housing 115, which is a metal cylinder,
have suffered severe damage due to the detonation of the charges
and these margins are now bent and in contact with the casing 130
of the well. This means that either there is a large friction
between the housing 115 and the casing 130, or the entire second
perforating gun 114 is stuck in the casing 130. This is undesirable
because the first perforating gun 112 needs to be moved to its
desired location relative to the oil and has formation 134, and
this action now cannot be completed because of the damaged housing
115.
[0006] Such severe deformation of the housing 115 of the
perforating gun 114 is possible to be prevented if the thickness of
the housing is increased or the housing is made of multiple layers.
However, these approaches impact the shaped charge's performance
and add weight, expense and complexity to the perforating gun, all
of which are undesirable.
[0007] Thus, there is a need for a new approach for preventing the
housing of the perforating gun from deforming or breaking into
pieces so that the perforating gun does not become stuck in the
casing.
SUMMARY
[0008] According to an embodiment, there a perforating gun for
perforating a casing of a well, and the perforating gun includes
one or more shaped charges configured to perforate the casing, a
loading tube configured to hold the one or more shaped charges, a
housing having a cylindrical shape and configured to receive inside
the loading tube and the one or more shaped charges, and a
protective tube located in an annulus formed between the housing
and the loading tube.
[0009] According to another embodiment, there is a perforating gun
for perforating a casing of a well. The perforating gun includes
one or more shaped charges configured to perforate the casing, a
loading tube configured to hold the one or more shaped charges, a
protective tube located around the loading tube and configured to
receive the one or more shaped charges in corresponding holes, and
a housing located around the protective tube.
[0010] According to still another embodiment, there is a method for
protecting a housing of a perforating gun from excessive damage.
The method includes placing one or more shaped charges into a
loading tube of a perforating gun, covering the loading tube with a
protective tube, and loading the loading tube with the protective
tube into a housing of the perforating gun. The protective tube is
located in an annulus formed between the loading tube and the
housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate one or more
embodiments and, together with the description, explain these
embodiments. In the drawings:
[0012] FIG. 1 illustrates a perforating gun having a housing
damaged by a detonated shaped charge so that the perforating gun
cannot move through the casing of the perforated well;
[0013] FIG. 2 illustrates a perforating gun having a protective
tube located in an annulus defined by a loading tube and the
housing, to protect the housing from excessive damage from the
shaped charges;
[0014] FIG. 3 shows a cross-section through the perforating gun of
FIG. 2, showing the protective tube disposed inside the housing,
and fully enclosing the loading tube;
[0015] FIG. 4 shows another implementation of the perforating gun
of FIG. 2, where the protective tube is formed of plural elements,
each element enclosing a corresponding portion of the loading
tube;
[0016] FIG. 5 shows a cross-section of the perforating gun having
legs that hold the protective tube around the loading tube;
[0017] FIG. 6 shows end plates of the perforating gun that have
slots for receiving corresponding tabs of the protective tube;
[0018] FIG. 7 shows an embodiment in which the protective tube is
hold exclusively by the shaped charges around the loading tube;
[0019] FIG. 8 shows the protective tube being made to include
plural discrete tubes; and
[0020] FIG. 9 is a flow chart of a method for adding a protective
tube to a perforating gun for protecting the housing from excessive
damage.
DETAILED DESCRIPTION
[0021] The following description of the embodiments refers to the
accompanying drawings. The same reference numbers in different
drawings identify the same or similar elements. The following
detailed description does not limit the invention. Instead, the
scope of the invention is defined by the appended claims. The
following embodiments are discussed, for simplicity, with regard to
a perforating gun used for perforating a casing in a well. However,
the embodiments discussed herein may be used for guns in another
context.
[0022] Reference throughout the specification to "one embodiment"
or "an embodiment" means that a particular feature, structure or
characteristic described in connection with an embodiment is
included in at least one embodiment of the subject matter
disclosed. Thus, the appearance of the phrases "in one embodiment"
or "in an embodiment" in various places throughout the
specification is not necessarily referring to the same embodiment.
Further, the particular features, structures or characteristics may
be combined in any suitable manner in one or more embodiments.
[0023] According to an embodiment, a perforating gun includes, in
addition to a loading tube that holds the shaped charges, and a
housing that encapsulates the shaped charges, a protective tube
that is provided between the loading tube and the casing. Thus, a
multi-layered loading tube includes an existing loading tube and
the protective tube. The protective tube is configured to limit the
possibility of the melted jet generated by the shaped charges to
severely damage the housing except for the intended location of the
perforation. In other words, the protective tube acts as a shield
protecting the housing of the perforating gun from the shaped
charge detonation effects which may include charge fragments, heat,
loading tube debris, pressure spikes, or other debris generated
during the detonation process.
[0024] More specifically, as shown in the embodiment of FIG. 2, a
perforating gun 200 includes one or more shaped charges 210 located
around and partially within a loading tube 220. The loading tube
220 may have plural holes 222 distributed with a desired pattern
and the plural holes 222 are configured to receive the plural
shaped charges 210. In one embodiment, each shaped charge 210 is
fixedly attached to a corresponding hole 222 formed into the
loading tube 220. The loading tube 220 and the shaped charges 210
are fully enclosed (except for their ends) by the housing 230. The
housing 230 separates the fluids from the well from the shaped
charges and the other components of the perforating gun 200, for
example, the detonation cord 212. The housing 230 may be processed
to have internal or external scallops or both, which correspond to
the shaped charges, so that the melted jet generated by a shaped
charge can easily make a perforation into the housing. FIG. 2 shows
only external scallops 232. However, none of the scallops extends
from one side of the housing to the other side so that the fluid
from the well is prevented from entering inside the perforating
gun.
[0025] FIG. 2 also shows a protective tube 240, which in this
embodiment is concentric to the loading tube 220 and to the housing
230. The protective tube 240 is thus located in the annulus 242
formed by the loading tube 220 and the housing 230. Note that each
of the loading tube 220, the protective tube 240, and the housing
230 has a cylindrical shape in this embodiment. While FIG. 2 shows
that the three cylinders are concentrical to each other, in one
application, the loading tube and/or the protective tube are not
concentric to the housing or to each other.
[0026] The protective tube 240 has plural through holes 244 that
correspond to the plural shaped charges 210. For example, as shown
in FIG. 2, each shaped charge 210 has a lip 214 that protrudes
through the holes 244 in the protective tube 240. FIG. 3 shows a
longitudinal cross-section through the perforating gun 200. It is
noted that the housing 230 has threads 234A and 234B at each end
230A and 230B, so that the housing 230 can be attached to a sub
300, for being attached to another perforating gun (not shown).
FIG. 3 also shows end plates 236A and 236B that close the ends of
the loading tube 220 and the protective tube 240 so that the inside
of the loading tube 220 is fluidly insulated from the outside of
the gun. FIG. 3 shows that the detonation cord 212 exits through
the end plates 236A and 236B, so that it can be connected to a
corresponding detonator 310, which can be placed either inside the
housing 230, or inside the sub 300. In one application, the
detonator 310 may be placed inside the loading tube 220, in which
case the element 212 in FIG. 3 is an electrical connection, for
example, a bulkhead assembly having one or more electrical
connections. The loading tube 220 is not visible in FIG. 3 because
it sits completely inside the protective tube 240. In one
application, the detonator 310 is placed inside the housing, but
outside the protective tube 240.
[0027] In another embodiment, the protective tube 240 is not
continuous, i.e., it does not extend over the entire length of the
loading tube 220, as shown in FIG. 4. In this embodiment, the
protective tube 240 includes plural elements 240-1 and 240-2, each
fully enclosing only a corresponding portion of the loading tube
220. The plural elements 240-1 and 240-2 (only two are shown in the
figure for simplicity, but their number is not limited, only by the
length of the loading tube) are shaped as cylinders. FIG. 4 shows
that only a portion of the loading tube 220 not being covered by
the elements 240-1 and 240-2. However, in one embodiment, plural
portions of the loading tube are not covered by the elements of the
protective tube 240.
[0028] The protective tube 240 may be attached to the interior of
the perforating gun in various ways. For example, FIG. 5 shows the
protective tube 240 being placed around the loading tube 220 and
having plural legs (e.g., screws or other fixtures) 500 that enter
through the protective tube 240 and sit on the outer surface of the
loading tube 220. The leg 500 has a tip portion 500A that sits in
direct contact with the outer surface of the loading tube 220 and a
head portion 500B that is located in the external annulus 242A,
formed between the protective tube 240 and the housing 230. Note
that the leg 500 extends throughout the wall of the protective tube
240 so that the tip portion 500A is located in the internal annulus
242B, formed between the protective tube 240 and the loading tube
220. The head portion 500B may have a rotating mechanism 502, for
example, a handle or a groove 502 that is configured to engage a
screwdriver or another tool. Thus, the person that assemblies the
perforating gun can adjust the amount of the leg 500 that is
located inside the internal annulus 242B, to effectively adjust the
position of the protective tube 240 relative to the loading tube
220, along a radial direction R. By operating three legs 500, the
two cylindric elements may be made concentric to each other. In one
embodiment, each end of the protective tube 240 may be provided
with the three legs 500.
[0029] In another embodiment, as illustrated in FIG. 6, the end
plates 236A and 236B (only one is shown for simplicity) may have
slots 600 that are configured to receive tabs 610 that are provided
at each end 240A and 240B of the protective tube 240. In this way,
the protective tube is connected to the end plates and does not
touch the loading tube 220 or the housing 230 and also does not
need the legs 500. The tabs 610 may be formed in any shape. In one
embodiment, no tabs are necessary as the protective tube 240 can be
attached with bolts or screws directly to the side plates. In one
application, the protective tube may be welded to the end plates.
The loading tube 220 may also be connected to the end plates in the
same manner as discussed above. In yet another embodiment, the
protective tube 240 may be bolted or snapped onto the loading tube
220. Any of these means may be combined for a given perforating
gun.
[0030] In yet another embodiment, the shaped charges 210 are used
to hold the protective tube 240 away from the loading tube 220, as
shown in FIG. 7. In other words, there is no leg, bolt, screw or
metal part present between the protective tube 240 and the loading
tube 220, except for the shaped charges 210. In yet another
embodiment, the protective tube 240 may be attached to the housing
230, for example, using wings attached to the exterior of the
protective tube 240 and these wings may be configured to engage
with corresponding locks provided on the interior surface of the
housing 230.
[0031] The spacing between the protective tube 240 and the loading
tube 220 may be selected to be between zero and several mm,
depending on the gun diameter and other design parameters
associated with the shaped charges. In one embodiment, the gap
between the two tubes may be even larger than several mm. The
loading tube, the protective tube and the housing may be made of
various materials. For example, all these elements may be made of
steel or similarly strong materials. In one application, these
elements may be made of different materials, for example, the
housing may be made of steel and the loading tube and the
protective tube may be made of a composite material.
[0032] By making the loading tube to be a multi-layer loading tube,
i.e., to include the additional protective tube, the housing of the
perforating gun is protected from severe damage with minimal
additional material and expense and without adding any material to
the housing, thus without changing the mass or thickness of the
housing. Therefore, the performance of the shaped charges is not
affected by the addition of the protective tube.
[0033] In yet another embodiment, the protective tube 240 may
include two or more tubes of varying thicknesses, as illustrated in
FIG. 8. For example, the protective tube 240 may have a first tube
810 having a first thickness and a second concentric tube 820
having a different thickness. More than two tubes may be used. The
first and second tubes may be in direct contact or have a small
annulus between them. The first and second tubes may be made from
the same material or different materials.
[0034] A method for protecting a housing of a perforating gun from
excessive damage is now discussed with regard to FIG. 9. The method
includes a step 900 of placing one or more shaped charges into a
loading tube of a perforating gun, a step 902 of covering the
loading tube with a protective tube, and a step 904 of loading the
loading tube with the protective tube into a housing of the
perforating gun. The protective tube is located in an annulus
formed between the loading tube and the housing.
[0035] The disclosed embodiments provide methods and systems for
adding a protective tube to a loading tube, between the loading
tube and the housing of a perforating gun, for minimizing the risk
of severely damaging the housing so that the perforating gun can
still move through the casing of the well after the shaped charges
are fired. It should be understood that this description is not
intended to limit the invention. On the contrary, the exemplary
embodiments are intended to cover alternatives, modifications and
equivalents, which are included in the spirit and scope of the
invention as defined by the appended claims. Further, in the
detailed description of the exemplary embodiments, numerous
specific details are set forth in order to provide a comprehensive
understanding of the claimed invention. However, one skilled in the
art would understand that various embodiments may be practiced
without such specific details.
[0036] Although the features and elements of the present exemplary
embodiments are described in the embodiments in particular
combinations, each feature or element can be used alone without the
other features and elements of the embodiments or in various
combinations with or without other features and elements disclosed
herein.
[0037] This written description uses examples of the subject matter
disclosed to enable any person skilled in the art to practice the
same, including making and using any devices or systems and
performing any incorporated methods. The patentable scope of the
subject matter is defined by the claims, and may include other
examples that occur to those skilled in the art. Such other
examples are intended to be within the scope of the claims.
* * * * *