U.S. patent application number 15/319704 was filed with the patent office on 2017-05-04 for fiber optic cable in det cord.
This patent application is currently assigned to Hunting Titan, Inc.. The applicant listed for this patent is Hunting Titan, Inc.. Invention is credited to Richard Wayne Bradley, William R. Collins, Andy Lane, Dale Langford, Charles Levine, Faraidoon Pundole, Rick Smith.
Application Number | 20170121236 15/319704 |
Document ID | / |
Family ID | 54936147 |
Filed Date | 2017-05-04 |
United States Patent
Application |
20170121236 |
Kind Code |
A1 |
Bradley; Richard Wayne ; et
al. |
May 4, 2017 |
Fiber optic cable in det cord
Abstract
An apparatus and method for providing a fiber optic cord in a
perforating gun.
Inventors: |
Bradley; Richard Wayne;
(Pinehurst, TX) ; Collins; William R.; (Burleson,
TX) ; Lane; Andy; (Pampa, TX) ; Langford;
Dale; (Pampa, TX) ; Levine; Charles;
(Waxahachie, TX) ; Pundole; Faraidoon; (Sugar
Land, TX) ; Smith; Rick; (Whitney, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hunting Titan, Inc. |
Pampa |
TX |
US |
|
|
Assignee: |
Hunting Titan, Inc.
Pampa
TX
|
Family ID: |
54936147 |
Appl. No.: |
15/319704 |
Filed: |
June 19, 2015 |
PCT Filed: |
June 19, 2015 |
PCT NO: |
PCT/US15/36731 |
371 Date: |
December 16, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62014931 |
Jun 20, 2014 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C06C 5/04 20130101; F42D
3/00 20130101; E21B 43/117 20130101; E21B 43/116 20130101; E21B
47/135 20200501 |
International
Class: |
C06C 5/04 20060101
C06C005/04; E21B 47/12 20060101 E21B047/12; E21B 43/117 20060101
E21B043/117 |
Claims
1. An elongated detonating cord comprising: an explosive encased in
a sheath; a fiber optic cable.
2. The detonating cord of claim 1 wherein the sheath and encased
explosives are substantially cylindrical.
3. The detonating cord of claim 1 wherein the fiber optic cable is
substantially parallel to the sheath.
4. The detonating cord of claim 1 further comprising an optical
shield between the fiber optic cable and the explosive.
5. The detonating cord of claim 3 wherein the fiber optic cable is
substantially coaxial with the sheath.
6. The detonating cord of claim 3 wherein the fiber optic cable is
affixed to the sheath.
7. The detonating cord of claim 3 wherein the fiber optic cable is
encased by the sheath.
8. The detonating cord of claim 3 wherein the fiber optic cable is
embedded in the sheath.
9. The detonating cord of claim 3 wherein the fiber optic cable is
spirally wound around the sheath.
10. The detonating cord of claim 7 wherein the fiber optic cable is
offset from a centerline of the sheath.
11. A method of perforating an oil well comprising: assembling a
string of perforating guns including a fiber optic cable; conveying
the string of perforating guns into a subterranean well;
communicating with the perforating guns using the fiber optic
cable.
12. The method of claim 11 further comprising: sending a detonation
signal to the perforating guns using the fiber optic cable;
detonating the perforating guns in response to the detonation
signal.
13. An integrated ballistic and optic communications cable
comprising: a tubular sheath; an explosive contained within the
sheath; a fiber optic cable.
14. The integrated ballistic and optic communications cable of
claim 13 wherein the sheath is substantially cylindrical.
15. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is substantially parallel to
the sheath.
16. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is substantially coaxial
with the sheath.
17. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is affixed to the
sheath.
18. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is encased by the
sheath.
19. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is embedded in the
sheath.
20. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is spirally wound around the
sheath.
21. The integrated ballistic and optic communications cable of
claim 18 wherein the fiber optic cable is offset from a centerline
of the sheath.
22. The integrated ballistic and optic communications cable of
claim 13 further comprising an optical shield between the fiber
optic cable and the explosive.
23. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is a single mode fiber optic
cable.
24. The integrated ballistic and optic communications cable of
claim 13 wherein the fiber optic cable is a multi-mode fiber optic
cable.
Description
RELATED APPLICATIONS
[0001] This application is the non-provisional of U.S. Provisional
Application No. 62/014,931, filed Jun. 20, 2014.
BACKGROUND OF THE INVENTION
[0002] Generally, when completing a subterranean well for the
production of fluids, minerals, or gases from underground
reservoirs, several types of tubulars are placed downhole as part
of the drilling, exploration, and completions process. These
tubulars can include casing, tubing, pipes, liners, and devices
conveyed downhole by tubulars of various types. Each well is
unique, so combinations of different tubulars may be lowered into a
well for a multitude of purposes.
[0003] A subsurface or subterranean well transits one or more
formations. The formation is a body of rock or strata that contains
one or more compositions. The formation is treated as a continuous
body. Within the formation hydrocarbon deposits may exist.
Typically a wellbore will be drilled from a surface location,
placing a hole into a formation of interest. Completion equipment
will be put into place, including casing, tubing, and other
downhole equipment as needed. Perforating the casing and the
formation with a perforating gun is a well known method in the art
for accessing hydrocarbon deposits within a formation from a
wellbore.
[0004] Explosively perforating the formation using a shaped charge
is a widely known method for completing an oil well. A shaped
charge is a term of art for a device that when detonated generates
a focused explosive output. This is achieved in part by the
geometry of the explosive in conjunction with an adjacent liner.
Generally, a shaped charge includes a metal case that contains an
explosive material with a concave shape, which has a thin metal
liner on the inner surface. Many materials are used for the liner;
some of the more common metals include brass, copper, tungsten, and
lead. When the explosive detonates the liner metal is compressed
into a super-heated, super pressurized jet that can penetrate
metal, concrete, and rock.
[0005] A perforating gun has a gun body. The gun body typically is
composed of metal and is cylindrical in shape. Within a typical gun
tube is a charge holder or carrier tube, which is a tube that is
designed to hold the actual shaped charges. The charge holder will
contain cutouts called charge holes where the shaped charges will
be placed.
[0006] A shaped charge is typically detonated by a booster or
primer. Shaped charges may be detonated by electrical igniters,
pressure activated igniters, or detonating cord. One way to ignite
several shaped charges is to connect a common detonating cord that
is placed proximate to the primer of each shaped charge. The
detonating cord is comprised of material that explodes upon
ignition. The energy of the exploding detonating cord can ignite
shaped charges that are properly placed proximate to the detonating
cord. Often a series of shaped charges may be daisy chained
together using detonating cord.
[0007] In addition to a detonating cord running through the
perforating gun, a wire may also run through the detonating cord.
The wire is used to enable power to the different switch systems.
The wires of multiple perforating guns connected together may also
be connected. The wire is sometimes run to control device on gun
string or sometimes it is run to a location at the surface with a
controller. Additionally, each perforating gun may have its own
control device for independent activation.
[0008] The problem with the wire is that is has poor reliability
due to shock and vibration. Also, the wire may increase inductance
that can inhibit communication signals along the gun string. This
inhibition can limit the length of the wire, which may limit the
depth of the drill string. Furthermore, the wire can suffer from
insulation loss. Insulation loss may result in sparking or arcing
between the wire and another conductor. The arcing or sparking may
cause pre-detonation of the explosive shaped charges, detonation
cord, or interfere with the electronics generally. Finally, the
wire is susceptible to radio frequency (RF) interference. RF
interference may cause unintended detonation of the explosives in
the perforating gun. As a result, the transportation of loaded
perforating guns maybe made safer by the removal of the wire.
SUMMARY OF EXAMPLES OF THE INVENTION
[0009] In this invention a fiber optic cable is used instead of a
wire to communicate with equipment on the perforating gun. Fiber
optics have been around for a long time, but they have not been
used in downhole perforating guns because of complexity,
reliability issues, and the difficulty of getting a powerful signal
to the shaped charges that has not been degraded by the Stimulated
Brioullin Scattering (SBS) effect. The Stimulated Brioullin
Scattering effect causes the transmission of signals in a fiber
optic cable to scatter and reflect in adverse ways that negates the
ability of a fiber optic cable to transmit enough power downhole to
cause a detonation. Newer fiber optic cables overcome these
problems and provide the potential for using a fiber optic over
many miles in length to communicate with a perforating gun located
in a harsh environment. This invention aims to provide a fiber
optic cable as an effective replacement for a wire on a perforating
gun.
[0010] An example of the invention may include an elongated
detonating cord comprising an explosive encased in a sheath and a
fiber optic cable. The sheath and encased explosives may be
substantially cylindrical. The fiber optic cable may be
substantially parallel to the sheath. The example may further
comprise an optical shield between the fiber optic cable and the
explosive. The fiber optic cable may be substantially coaxial with
the sheath. The fiber optic cable may be affixed to the sheath. The
fiber optic cable may be encased by the sheath. The fiber optic
cable may be embedded in the sheath. The fiber optic cable may be
spirally wound around the sheath. The fiber optic cable may be
offset from the centerline. The fiber optic cable may be single
mode or multi-mode. The fiber optic cable may include one or more
optical fibers encased in a shield.
[0011] Another example of the invention may include a method of
perforating an oil well comprising assembling a string of
perforating guns including a fiber optic cable, conveying the
string of perforating guns into a subterranean well, communicating
with the perforating guns using the fiber optic cable. The example
may further comprise sending a detonation signal to the perforating
guns using the fiber optic cable and detonating the perforating
guns in response to the detonation signal. The fiber optic cable
may be single mode or multi-mode. The fiber optic cable may include
one or more optical fibers encased in a shield.
[0012] Another example of the invention may include an integrated
ballistic and optic communications cable comprising a tubular
sheath, an explosive contained within the sheath, and a fiber optic
cable. The sheath may be substantially cylindrical. The fiber optic
cable may be substantially parallel to the sheath. The fiber optic
cable may be substantially coaxial with the sheath. The fiber optic
cable may be affixed to the sheath. The fiber optic cable may be
encased by the sheath. The fiber optic cable may be embedded in the
sheath. The fiber optic cable may be spirally wound around the
sheath. The fiber optic cable may be offset from the centerline.
The example may further comprise an optical shield between the
fiber optic cable and the explosive. The fiber optic cable may be
single mode or multi-mode. The fiber optic cable may include one or
more optical fibers encased in a shield.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a thorough understanding of the present invention,
reference is made to the following detailed description of the
preferred embodiments, taken in conjunction with the accompanying
drawings in which reference numbers designate like or similar
elements throughout the several figures of the drawing.
Briefly:
[0014] FIG. 1 is a detonating cord with an internally located
coaxial fiber optic cable.
[0015] FIG. 2 is a detonating cord with an internally located
off-centered fiber optic cable.
[0016] FIG. 3 is a cross section of a detonating cord with an
internally located off-centered fiber optic cable.
[0017] FIG. 4 is a detonating cord bundled to a fiber optic
cord.
[0018] FIG. 5 is a charge tube wrapped with a detonating cord
bundled to a fiber optic cord.
DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION
[0019] In the following description, certain terms have been used
for brevity, clarity, and examples. No unnecessary limitations are
to be implied therefrom and such terms are used for descriptive
purposes only and are intended to be broadly construed. The
different apparatus, systems and method steps described herein may
be used alone or in combination with other apparatus, systems and
method steps. It is to be expected that various equivalents,
alternatives, and modifications are possible within the scope of
the appended claims.
[0020] A typical perforating gun comprises a gun body that houses a
charge tube, which further houses the shaped charges. The gun body
contains end fittings which secure the charge tube inside the
perforating gun. The charge tube has charge holes and apex holes
for installing shaped charges. The gun body may have threaded ends
that allow it to be connected to a series of perforating guns or to
other downhole tubulars. Typically the detonating cord runs the
majority of the length of the gun body. One or more shaped charges
can be placed in the charge tube. Sometimes the shaped charges can
all point in the same direction, other times some or all may be
oriented in different directions about the center axis of the
charge tube. Different orientations of the shaped charges may have
different angles between each shaped charge. The detonating cord
wraps around the charge tube to accommodate the different
orientations of the shaped charges in phased perforating guns.
[0021] The shaped charges include a shaped charge case that holds
the energetic material, a liner and an explosive. The shaped charge
case typically is composed of a high strength metal, such as alloy
steel. The liner is usually composed of a powdered metal that is
either pressed or stamped into place. The metals used in liner may
include brass, copper, tungsten, and lead.
[0022] An example of an embodiment of the invention may include a
perforating gun with a charge tube located within the perforating
gun. The charge tube would contain cutouts for each shaped charge.
The fiber optic cable may be adapted to interface with the shaped
charges located in the charge tube. The fiber optic cable may wind
around the charge tube such that all of the shaped charges are
connected to the same fiber optic cable.
[0023] The fiber optic cable in this example could terminate at
either end of the charge tube and interface with another
communication device or another fiber optic cable. The fiber optic
could eventually reach the surface where the operator can control
the perforating gun. The perforating gun could be detonated by
sending a signal downhole through the fiber optic cable. The
detonation command could be achieved by a single pulse or a series
of pulses. The pulses could be used to detonate all the shaped
charges, individual shaped charges in a unique sequence, or
individual perforating guns.
[0024] Referring to FIG. 1, a fiber optic cable 52 is located
within a detonating cord 51. Detonating cord 51 includes explosive
material 59 enclosed in a sheath 58. The fiber optic cable 52 may
include one or more optical fibers 60 encased in a shield 61. The
fiber optic cable may be single mode or multi-mode. In this example
the fiber optic cable 52 is located substantially centrally within
the detonating cord 51. The fiber optic cable 52 may have one or
more Application Specific integrated Circuit (referred to as
"ASIC") devices 53 attached that could be capable of interfacing
with a device outside of the detonating cord 51. The ASIC device 53
may be secured to the fiber optic cable 52 by snapping, screwing,
adhering to, or press fitting.
[0025] In another example, as shown in FIG. 2, the fiber optic
cable 52 is located off-center within the detonating cord 51.
Detonating cord 51 includes explosive material 59 enclosed in a
sheath 58. At one or more locations along the fiber optic cord 52
there may be an ASIC device 53 attached as shown in FIG. 3. In the
example shown, a signal could be sent or received through the fiber
optic cable 52 and that signal could then be sent to a device
outside of the detonating cord 51. Types of devices that could be
attached to the ASIC device 53 may include sensors, detonators,
switches, or communication devices. In this example the ASIC device
53 is configured to allow the fiber optic cable 52 to communicate
with other electronics outside of the detonating cord sheath 58.
The fiber optic cable offers the advantage of being radio frequency
(RF) interference free as opposed to a conductive wire because a
fiber optic does not transmit electricity, therefore it is
considered safer that a conductor such as a wire.
[0026] In another example, as shown in FIG. 4, the fiber optic
cable 52 is affixed to the outside of a detonating cord 51 to make
an integrated communications cable 55. The fiber optic cable 52 is
bundled to the detonating cord 51 using a fastening device 54. The
fastening device 54 shown is a tie that wraps around both the fiber
optic cable 52 and the detonating cord 51. The fastening device 54
may be a metal or plastic tie, a cable, a wire, u-bolt, a ring,
additional sheath, tape, heat shrink, tubing, conduit, adhesive or
a similar fastening mechanism.
[0027] The integrated communications cable 55 may then be wrapped
around a charge tube 57 as shown in FIG. 5. A charge tube 57 holds
shaped charges and is then placed inside a perforating gun. In a
typical perforating job, shaped charges may be lined up along the
charge tube 57 all pointing the same direction, which is referred
to as zero phase. The shaped charges may be offset from each other
by rotating a certain number of degrees about the center of the
charge tube 57 from one shaped charge to the next. The offset angle
is referred to as the phase angle. Because the charges are often
offset from each other and therefore pointing in different
directions, the integrated communications cable 55 has to wrap
around the gun such that the detonating cord 51 and the fiber optic
cable 52 may interface with each and every shaped charges apex. The
shaped charge apex may have additional equipment or devices
attached to it. Generally the shaped charge apex will be located at
an apex hole on the shaped charge.
[0028] In the example of FIG. 5, the integrated communications
cable 55 may be attached to the charge tube 57 using a variety of
fastening devices 54 including ties, wires, cables, rings, u-bolts,
or similar fastening mechanisms. Further, the fiber optic cord 52
may be individually secured to the charge tube 57 using a variety
of fastening devices 56 including metal or plastic tie, a cable, a
wire, a ring, additional sheath, tape, heat shrink, tubing,
u-bolts, conduit, adhesive or a similar fastening mechanism. The
integrated communications cable 55 may also be fastened to the
shaped charges directly.
[0029] Although the invention has been described in terms of
particular embodiments which are set forth in detail, it should be
understood that this is by illustration only and that the invention
is not necessarily limited thereto. Alternative embodiments and
operating techniques will become apparent to those of ordinary
skill in the art in view of the present disclosure. Accordingly,
modifications of the invention are contemplated which may be made
without departing from the spirit of the claimed invention.
* * * * *