U.S. patent application number 17/500111 was filed with the patent office on 2022-04-28 for low-drag perforating gun scallops and method.
The applicant listed for this patent is GEODYNAMICS, INC.. Invention is credited to James A. ROLLINS, Wenbo YANG.
Application Number | 20220127936 17/500111 |
Document ID | / |
Family ID | |
Filed Date | 2022-04-28 |
United States Patent
Application |
20220127936 |
Kind Code |
A1 |
YANG; Wenbo ; et
al. |
April 28, 2022 |
LOW-DRAG PERFORATING GUN SCALLOPS AND METHOD
Abstract
A perforating gun for making perforations in a well, the
perforating gun including a carrier extending along a longitudinal
axis X and having a bore; a tube extending along the longitudinal
axis X and having a radius smaller than a radius of the carrier so
that the tube slides inside the bore of the carrier; a shaped
charge placed inside the tube and configured to make a hole through
the carrier; and a scallop formed in a body of the carrier,
corresponding to a location of the shaped charge along the
longitudinal axis X. The scallop has a side surface that makes an
angle .alpha. with the longitudinal axis X, and the angle .alpha.
is different from 90 degrees.
Inventors: |
YANG; Wenbo; (Arlington,
TX) ; ROLLINS; James A.; (Lipan, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GEODYNAMICS, INC. |
Millsap |
TX |
US |
|
|
Appl. No.: |
17/500111 |
Filed: |
October 13, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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63105959 |
Oct 27, 2020 |
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International
Class: |
E21B 43/117 20060101
E21B043/117 |
Claims
1. A perforating gun for making perforations in a well, the
perforating gun comprising: a carrier extending along a
longitudinal axis X and having a bore; a tube extending along the
longitudinal axis X and having a radius smaller than a radius of
the carrier so that the tube slides inside the bore of the carrier;
a shaped charge placed inside the tube and configured to make a
hole through the carrier; and a scallop formed in a body of the
carrier, corresponding to a location of the shaped charge along the
longitudinal axis X, wherein the scallop has a side surface that
makes an angle .alpha. with the longitudinal axis X, and the angle
.alpha. is different from 90 degrees.
2. The perforating gun of claim 1, wherein the angle .alpha. is
between 15 and 80 degrees.
3. The perforating gun of claim 1, wherein the scallop is made on
an external surface of the body of the carrier.
4. The perforating gun of claim 1, wherein a value of the angle
.alpha. is correlated with a value of an internal diameter of the
carrier.
5. The perforating gun of claim 1, wherein the scallop has a bottom
circular circumference and a top non-circular circumference.
6. The perforating gun of claim 5, wherein the top non-circular
circumference is elliptical.
7. The perforating gun of claim 5, wherein the top non-circular
circumference has first and second diameters, with the first
diameter being larger than the second diameter.
8. The perforating gun of claim 7, wherein the first diameter is
substantially equal to an outside diameter of the shaped
charge.
9. The perforating gun of claim 1, wherein the side surface of the
scallop is formed of a first region having a first curvature radius
and a second region having a second curvature region.
10. The perforating gun of claim 9, wherein the first curvature
radius is smaller than the second curvature radius.
11. The perforating gun of claim 1, wherein a longitudinal axis Z
of the shaped charge makes a non-zero angle with a radial axis R of
the carrier, and a central point of the scallop is located along
the longitudinal axis Z.
12. A carrier of a perforating gun for making perforations in a
well, the carrier comprising: a body extending along a longitudinal
axis X and having a bore; and a scallop formed in the body of the
carrier, corresponding to a location of a shaped charge of the
perforating gun along the longitudinal axis X, wherein the scallop
has a side surface that makes an angle .alpha. with the
longitudinal axis X, and the angle .alpha. is different from 90
degrees.
13. The carrier of claim 12, wherein the angle .alpha. is between
15 and 80 degrees.
14. The carrier of claim 12, wherein the scallop is made on an
external surface of the body.
15. The carrier of claim 12, wherein a value of the angle .alpha.
is correlated with a value of an internal diameter of the
carrier.
16. The carrier of claim 12, wherein the scallop has a bottom
circular circumference and a top non-circular circumference.
17. The carrier of claim 16, wherein the top non-circular
circumference is elliptical having first and second diameters, with
the first diameter being larger than the second diameter.
18. The carrier of claim 17, wherein the first diameter is
substantially equal to an outside diameter of the shaped
charge.
19. The carrier of claim 12, wherein the side surface of the
scallop is formed of a first region having a first curvature radius
and a second region having a second curvature region, and wherein
the first curvature radius is smaller than the second curvature
radius.
20. The carrier of claim 12, wherein a longitudinal axis Z of the
shaped charge makes a non-zero angle with a radial axis R of the
carrier, and a central point of the scallop is located on the
longitudinal axis Z.
Description
BACKGROUND
Technical Field
[0001] Embodiments of the subject matter disclosed herein generally
relate to a system and method for delivering one or more
perforating guns to a given location in a wellbore, and more
particularly, to minimizing the risk of having the one or more
perforating guns being caught on casing couplings, perforations or
other restrictions that are present in a wellbore.
Discussion of the Background
[0002] During a well completion process, a gun string assembly 100,
as shown in FIG. 1, which includes plural perforation guns 110
(only one is shown for simplicity), is positioned in an isolated
zone in the wellbore's casing 130. The perforating guns 110 are
coupled to each other, either through tandems or subs 112. One or
more of the perforating guns 110 are then fired, creating holes 113
through the casing 130 and the cement 132 and into the targeted
rock formation 134. These perforating holes allow fluid
communication between the formation containing the oil and gas, and
the wellbore. The firing of the perforating gun detonates charges
116 that are loaded within the perforation gun. Typically, these
are shaped charges that produce an explosive-formed penetrating jet
in the chosen direction in which the charge is directed.
[0003] The perforating gun 110 includes a conveyance for the shaped
charges 116, such as a hollow carrier 118, often in the shape of a
tube, charge holder end plates (not shown), shaped charges 116, a
detonating cord 120, and the detonator 122. The tube 118 with the
shaped charges 116 is placed within a gun carrier 124, which body
124' is made of metal and is configured to prevent a well fluid 136
to reach the shaped charges 116 and the detonator 122. In general,
the shaped energetic charges 116 perforate through scallops 126,
which are formed on the outside of the body 124' of the gun carrier
124 of the perforating gun 110. Typical high shot density
perforating guns employ an array of shaped charges spaced at
intervals along the length of the perforating gun. Each array
typically utilizes three or four shaped charges with each array
spaced three to four inches apart.
[0004] Standard perforating gun scallop (or spotface) designs are
features on an inner and/or outer gun carrier 124's body and they
are intended to reduce the wall's thickness that a shape charge 116
must fire through. Typical scallops 126 are machined perpendicular
to the carrier 124's wall, as shown in FIG. 2. The term
"perpendicular" in this context means that a side 127 of the
scallop 126 extends along longitudinal axis Z of the shaped charge
116 (the longitudinal axis Z is also the radial axis of the
carrier), which is perpendicular on the longitudinal axis X of the
carrier 124 or tube 118. Such machining leaves an elevated edge or
ridge 128 along the periphery of the scallop 126, i.e., a feature
that creates a potential snag point on the carrier 124 that can
catch on the casing 130 and increase friction when deploying or
retrieving the perforating gun 110 from the wellbore.
[0005] Perforating guns are also prone to get caught on casing
couplings, perforations, and other restrictions as the standard
spot faces typically has a 90 deg angle side wall to the scallop as
shown in FIG. 2. In addition, when the shaped charge is angled for
angled perforating, the standard scallop with perpendicular sides
results in the perforating jet at least partially hitting the
carrier wall outside the scallop, thus disturbing the shape of the
jet, which results in a decrease in the perforating gun performance
and quality of perforation.
[0006] Thus, there is a need for a new system that is capable of
reducing the thickness of the carrier's wall without negatively
impacting the moving of the perforating guns in and out of the
wellbore.
BRIEF SUMMARY OF THE INVENTION
[0007] According to an embodiment, there is a perforating gun for
making perforations in a well. The perforating gun includes a
carrier extending along a longitudinal axis X and having a bore, a
tube extending along the longitudinal axis X and having a radius
smaller than a radius of the carrier so that the tube slides inside
the bore of the carrier, a shaped charge placed inside the tube and
configured to make a hole through the carrier, and a scallop formed
in a body of the carrier, corresponding to a location of the shaped
charge along the longitudinal axis X. The scallop has a side
surface that makes an angle .alpha. with the longitudinal axis X,
and the angle .alpha. is different from 90 degrees.
[0008] According to another embodiment, there is a carrier of a
perforating gun for making perforations in a well. The carrier
includes a body extending along a longitudinal axis X and having a
bore, and a scallop formed in the body of the carrier,
corresponding to a location of a shaped charge of the perforating
gun along the longitudinal axis X. The scallop has a side surface
that makes an angle .alpha. with the longitudinal axis X, and the
angle .alpha. is different from 90 degrees.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of the present invention,
reference is now made to the following descriptions taken in
conjunction with the accompanying drawings, in which:
[0010] FIG. 1 is a schematic diagram of a perforating gun placed in
a horizontal well;
[0011] FIG. 2 shows a traditional scallop made in a wall of the
carrier of the perforating gun and having a side surface
perpendicular to a longitudinal axis of the carrier;
[0012] FIG. 3 illustrates a new scallop made in the wall of the
carrier and having a side surface that is not perpendicular to the
longitudinal axis of the carrier;
[0013] FIG. 4 is a perspective view of the scallop and the
carrier;
[0014] FIGS. 5A and 5B show cross-sectional views of the scallop
and the carrier;
[0015] FIGS. 6A and 6B show longitudinal sectional views of the
scallop and the carrier;
[0016] FIG. 7 shows in more detail the shape of the scallop;
[0017] FIG. 8 shows another possible shape of the side surface of
the scallop;
[0018] FIG. 9 shows an angled shaped charge and the location of the
scallop to accommodate the jet generated by the such a charge;
and
[0019] FIG. 10 is a flow chart of a method for making a scallop
having non-perpendicular sides.
DETAILED DESCRIPTION OF THE INVENTION
[0020] 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 scallop with a tapered side of 35 degrees relative to a
longitudinal axis of the carrier. However, the embodiments to be
discussed next are not limited to such a taper angle, but may be
applied with other angles, for example, between 15 and 80
degrees.
[0021] 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.
[0022] According to an embodiment, a novel perforating gun has one
or more scallops formed in the body of the carrier, so that the
sides of the scallop are not perpendicular to the surface of the
body, but rather make an angle, between 15 and 80 degrees, with the
surface of the body. This smooth transition spotface side wall is
less likely to get stuck or jammed on or with imperfections in the
casing.
[0023] More specifically, as shown in FIG. 3, a perforating gun 110
has one or more shaped charges 116 distributed within a tube 118,
which is placed inside a carrier 124. An external surface 124A of
the body 124' of the carrier 124 has at least a scallop 310 aligned
with a corresponding shaped charge 116. The term "aligned" in this
context means that a symmetry or longitudinal axis Z of the shaped
charge 116 is coincident with a symmetry axis of the scallop 310. A
side wall 312 of the scallop 310 makes an angle .alpha. with the
external surface 124A (which is parallel to the longitudinal axis X
of the carrier 124) of the carrier 124, and this angle is between
15 and 80 degrees. In one embodiment, the selection of the value of
the angle .alpha. is correlated with the value of the internal
diameter D of the carrier 124. For example, it has been found by
the inventors that for a diameter D of 7.92 cm, the desired angle
.alpha. is about 35 degrees.
[0024] The shape of the scallop 310 and its side surface 312 are
further illustrated in FIG. 4. A transversal cross-section A-A
through the scallop is shown in FIGS. 5A and 5B and a longitudinal
cross-section B-B through the scallop is shown in FIGS. 6A and 6B.
It is noted that a bottom surface 314 of the scallop 310 is located
within the body 124' of the carrier 124, and does not communicate
with the bore 125 of the carrier 124. FIG. 7 shows these features
at a larger scale for easy visualization. The smooth transition
side surface 312 is less likely to get stuck or jammed on or with
imperfections in the casing 130. FIG. 7 also shows a bore 131 of
the casing 130 and how the carrier 124 is placed inside the bore
131 and the scallop 310 faces the inside wall of the casing
130.
[0025] While the scallop 310 may have a perfectly circular shape,
in one embodiment, as shown in FIG. 6B, the scallop has a bottom
circular circumference 610 and a top non-circular circumference
620, for example, an elliptical shape. In this embodiment, the
large diameter LD (see FIG. 7) of the top non-circular
circumference 620 extends along the X axis while its small diameter
SD extends along the circumference of the carrier 124 (see FIG.
6B). These orientations may be changed as necessary.
[0026] In another embodiment, the large diameter LD of the top
non-circular circumference 620 is selected to be substantially
equal to the opening diameter OP of the top surface of the shaped
charge 116, i.e., the opening through which the jet is expelled
when the shaped charge is fired (see FIG. 3). The term
"substantially" is understood herein to mean 10% or less than the
reference length.
[0027] In yet another embodiment, as illustrated in FIG. 8, the
side surface 312 of the scallop 310 may be configured to be curved
(for example, the entire surface is curved), with a first radius R1
of curvature for the region 810 defining the top circumference 620
and a second radius R2 of curvature for the region 820 defining the
bottom circumference 610. The first and second radii of curvature
are different, with the first radius being smaller than the second
radius. In this way, the first region 810 and the second region 820
form the side surface 312 of the scallop 310. The first region 810,
by being curved and smooth, ensures that there is no strong
engagement with the casing 130 when sliding along the casing.
[0028] In one application, it is possible to coat the side surface
312 of the scallop 310 (e.g., only the region 810) with a material
830 that has a smaller friction coefficient with the casing 130
than the wall of the carrier 124, so that there is less friction
when the perforating gun 110 advances in a horizontal well. The
coating material 310 may be placed, for example, only on the region
810, or both on the wall 124A of the carrier 124 and the region
810. In one application, the coating material 810 is graphite, or
copper or brass, or an acrylic material or an equivalent
material.
[0029] In another embodiment, the shaped charge 116 is placed at a
non-zero angle .beta. relative to the radial axis R (which is
defined as a radial direction of the tube 118), as shown in FIG. 9.
This arrangement of the shaped charge is called herein an angled
shaped charge. For this situation, depending on the value of the
angle .beta., the position of the scallop 310 is adjusted relative
to the body of the carrier 124 so that a central location 810 of
the scallop 310 sits on the longitudinal axis Z of the shaped
charge 116. This means that the large diameter LD (see FIG. 7) of
the scallop 310 is still substantially equal to the outside
diameter OD of the shaped charge. To achieve this relationship, the
entire location of the scallop 310 is shifted along the
longitudinal axis X of the carrier 124. The scallop 310 for this
case may have any or all features of the scallops previously
discussed, i.e., the various features of the scallops discussed in
the previous embodiments may be combined in any way in this or
another embodiment. In one application, it is possible that the a
and .beta. angles are substantially equal to each other. While the
scallops discussed herein have been provided on the outside wall of
the carrier 124, the same type of scallop may be provided on the
inside wall of the carrier.
[0030] With angled perforating as with Geodynamics' SandIQ system,
there is an additional benefit of having the scallop 310, in that
the shaped charge is also tilted to a similar angle to correspond
to the angled or tapered side wall. This combination results in a
target spotface that is easier to hit with the charge jet without
damaging the side of the carrier. With the "low drag scallop," the
perforating jet has a larger area to shoot thru without hitting the
carrier.
[0031] A method for making a carrier 124 having one of the scallops
310 discussed above is now discussed with regard to FIG. 10. The
method starts with a step 1000 of providing the body 124' of the
carrier, which extends along the longitudinal axis X and has a bore
125. In step 1002, the scallop 310 is machined to have a side
surface 312 and a bottom surface 314. This step may include a
substep of making the bottom surface 314 to be circular and a top
circumference to be non-circular. The side surface 312 is
manufactured to make an angle .alpha. with the longitudinal axis,
and the angle .alpha. is different from 90 degrees. In one
application, the angle .alpha. is between 15 and 80 degrees. The
method may further include making the scallop on an external
surface of the carrier. The method may also include an optional
step 1004 of selecting a value of the angle .alpha. to be
correlated with a value of an internal diameter of the carrier.
[0032] The scallop has a bottom circular circumference and a top
non-circular circumference where the top non-circular circumference
is elliptical. In one application, the top non-circular
circumference has first and second diameters, with the first
diameter being larger than the second diameter. The first diameter
may be substantially equal to an outside diameter of the shaped
charge. In yet another application, which may be combined with any
of the previous application or embodiments, the side surface of the
scallop is formed of a first region having a first curvature radius
and a second region having a second curvature region. The first
curvature radius is smaller than the second curvature radius. In
one application, a longitudinal axis Z' of the shaped charge makes
a non-zero angle with a radial axis Z of the carrier, and a central
point of the scallop is located along the longitudinal axis Z'.
[0033] The disclosed embodiments provide a scallop on the wall of
the carrier of a perforating gun and the scallop has a side surface
not perpendicular to the surface of the wall, so that a smooth
contact surface is formed between the carrier and the casing in
which the carrier is placed. It should be understood that this
description is not intended to limit the invention. On the
contrary, the 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 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.
[0034] Although the features and elements of the present
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.
[0035] 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.
* * * * *