U.S. patent application number 17/254198 was filed with the patent office on 2021-04-29 for tethered drone for downhole oil and gas wellbore operations.
This patent application is currently assigned to DynaEnergetics Europe GmbH. The applicant listed for this patent is DynaEnergetics Europe GmbH. Invention is credited to Christian Eitschberger, Liam McNelis, Thilo Scharf, Shmuel Silverman, Andreas Robert Zemla.
Application Number | 20210123330 17/254198 |
Document ID | / |
Family ID | 1000005328294 |
Filed Date | 2021-04-29 |
United States Patent
Application |
20210123330 |
Kind Code |
A1 |
Eitschberger; Christian ; et
al. |
April 29, 2021 |
TETHERED DRONE FOR DOWNHOLE OIL AND GAS WELLBORE OPERATIONS
Abstract
According to some embodiments, devices, systems, and methods for
conveying downhole oil and gas wellbore tools and performing
downhole oil and gas wellbore operations are disclosed. The
exemplary devices, systems, and methods may include a tethered
drone that substantially disintegrates and/or dissolves into a
proppant when shaped charges that the tethered drone carries are
detonated. Two or more tethered drones, wellbore tools, and/or data
collection devices may be connected in a tethered drone string for
efficiently performing wellbore operations and reducing the amount
of debris left in the wellbore after such operations.
Inventors: |
Eitschberger; Christian;
(Munich, DE) ; McNelis; Liam; (Bonn, DE) ;
Scharf; Thilo; (Letterkenny, Donegal, IE) ; Zemla;
Andreas Robert; (Much, DE) ; Silverman; Shmuel;
(Novato, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DynaEnergetics Europe GmbH |
Troisdorf |
|
DE |
|
|
Assignee: |
DynaEnergetics Europe GmbH
Troisdorf
DE
|
Family ID: |
1000005328294 |
Appl. No.: |
17/254198 |
Filed: |
March 29, 2019 |
PCT Filed: |
March 29, 2019 |
PCT NO: |
PCT/IB2019/000530 |
371 Date: |
December 18, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62690314 |
Jun 26, 2018 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/1185 20130101;
E21B 43/119 20130101; E21B 43/117 20130101; E21B 47/017
20200501 |
International
Class: |
E21B 43/117 20060101
E21B043/117; E21B 43/119 20060101 E21B043/119; E21B 47/017 20060101
E21B047/017; E21B 43/1185 20060101 E21B043/1185 |
Claims
1. A single-piece, self-contained tethered drone, comprising: a
body portion; a head portion extending from the body portion and
including an integrated electrical and mechanical connecting
assembly; a tail portion extending from the body portion in a
direction opposite the head portion; a wellbore data collection
device housed within the drone and configured for electrically
connecting to a wireline; and at least one shaped charge, wherein
the tethered drone is formed at least in part from a material that
will substantially disintegrate upon detonating the shaped charge,
while the wellbore data collection device remains intact and
operable for delivering the collected data.
2. The tethered drone of claim 1, further comprising a detonator
and optionally, a detonating cord coupled to the detonator, and a
plurality of shaped charges received in shaped charge apertures in
the body portion, wherein the shaped charge apertures are
respectively positioned adjacent to at least one of the detonator
and the detonating cord within an interior of the body portion.
3. The tethered drone of claim 2, further comprising circuitry
positioned within the tail portion and programmed to receive a
selective detonation signal from a control unit via the wireline
and to transmit the selective detonation signal to the
detonator.
4. The tethered drone of claim 3, wherein the integrated electrical
and mechanical connecting assembly includes an electrically
conductive pin connector and a mechanical connector respectively
configured for connecting to a complementary electrical component
and a complementary mechanical connector.
5. The tethered drone of claim 4, further comprising a conductive
wire configured for relaying an electrical signal along a length of
the tethered drone from the circuitry to the pin connector.
6. The tethered drone of claim 5, wherein the complementary
electrical component and the complementary mechanical connector are
parts of a complementary drone separate and distinct from the
tethered drone, and the integrated electrical and mechanical
connecting assembly of the head portion of the tethered drone is
configured for electrically connecting the pin connector of the
integrated electrical and mechanical assembly to the complementary
electrical component of the complementary drone when the mechanical
connector of the integrated electrical and mechanical assembly is
connected to the complementary mechanical connector of the
complementary drone to connect the tethered drone to the
complementary drone, and the head portion, alone, provides an
electrical transfer and mechanical coupling for connecting the
tethered drone to the complementary drone via the conductive wire,
the pin connector, and the mechanical connector.
7. The tethered drone of claim 5, wherein the conductive wire is
configured for receiving the electrical signal from the wireline
via a direct connection or through one or more electrically
conductive components.
8. The tethered drone of claim 1, wherein the wellbore data
collection device is configured for receiving at least one of a
power supply and an electrical signal from the wireline via a
direct connection or through one or more electrically conductive
components.
9. The tethered drone of claim 1, wherein the wellbore data
collection device is the only removeable component of the tethered
drone after detonating the shaped charge, and the wellbore data
collection device is configured for being removed from the wellbore
by the wireline.
10. A single-piece, self-contained tethered drone, comprising: a
body portion; a head portion extending from the body portion; a
tail portion extending from the body portion in a direction
opposite the head portion and configured for connecting to a
wireline, wherein the tail portion includes an electrical transfer
contact and circuitry for receiving an electrical signal from a
control unit via the wireline; a detonator and optionally, a
detonating cord coupled to the detonator, wherein the circuitry
transmits the electrical signal to the detonator; and a plurality
of shaped charges received in shaped charge apertures in the body
portion, wherein the shaped charge apertures are respectively
positioned adjacent to at least one of the detonator and the
detonating cord within an interior of the body portion, wherein the
tethered drone is formed at least in part from a material that will
substantially disintegrate upon detonating the shaped charge.
11. The tethered drone of claim 10, wherein the head portion
includes an integrated electrical and mechanical connecting
assembly, and the head portion, alone, provides an electrical
transfer and mechanical coupling for electrically and mechanically
connecting the tethered drone to a complementary electrical
component and a complementary mechanical component of a
complementary drone separate and distinct from the tethered
drone.
12. A tethered drone string for downhole delivery of one or more
wellbore tools, comprising: a first single-piece, self-contained
tethered drone connected to a second single-piece, self-contained
tethered drone, the first tethered drone and the second tethered
drone respectively including a body portion, a head portion, a tail
portion, and at least one shaped charge, wherein the head portion
of the first tethered drone extends from the body portion of the
first tethered drone in a direction towards the second tethered
drone and includes an integrated electrical and mechanical
connecting assembly, the tail portion of the first tethered drone
extends from the body portion of the first tethered drone in a
direction opposite the head portion and includes a tail connecting
portion, wherein the tail connecting portion of the first tethered
drone is configured for at least one of connecting to a wellbore
tool and connecting to a wireline, the tail portion of the second
tethered drone includes a tail connecting portion, wherein the tail
connecting portion of the second tethered drone is electrically and
mechanically connected to the integrated electrical and mechanical
connecting assembly of the first tethered drone, and the head
portion of the first tethered drone, alone, provides an electrical
transfer and mechanical coupling between the first tethered drone
and the second tethered drone via the integrated electrical and
mechanical connecting assembly; and a wellbore data collection
device configured for at least one of forming a connection between
the first tethered drone and the second tethered drone, forming a
connection between at least one of the first tethered drone and the
second tethered drone respectively and the wireline, and being
housed within at least one of the first tethered drone and the
second tethered drone, wherein the first tethered drone and the
second tethered drone are formed at least in part from a material
that will substantially disintegrate upon detonating the shaped
charge, while the wellbore data collection device remains intact
and operable for delivering the collected data.
13. The tethered drone string of claim 12, wherein the first
tethered drone and the second tethered drone respectively include a
detonator and optionally, a detonating cord coupled to the
detonator, and a plurality of shaped charges received in shaped
charge apertures in the body portion, wherein the shaped charge
apertures are respectively positioned adjacent to at least one of
the detonator and the detonating cord within an interior of the
body portion.
14. The tethered drone string of claim 13, wherein the first
tethered drone alone includes circuitry positioned within the tail
portion of the first tethered drone and programmed to receive a
selective detonation signal from a control unit via the wireline
and transmit the selective detonation signal to the respective
detonator in each of the first tethered drone and the second
tethered drone.
15. The tethered drone string of claim 14, wherein the first
tethered drone further includes a conductive wire configured for
relaying the selective detonation signal along a length of the
first tethered drone from the circuitry to the integrated
electrical and mechanical connecting assembly.
16. The tethered drone string of claim 15, wherein the integrated
electrical and mechanical connecting assembly transfers the
selective detonation signal, via the tail connecting portion of the
second tethered drone, from the conductive wire to the detonator of
the second tethered drone.
17. The tethered drone string of claim 16, wherein the integrated
electrical and mechanical connecting assembly of the first tethered
drone includes an electrically conductive pin connector
electrically connected to an electrical transfer contact of the
tail connecting portion of the second tethered drone and a
mechanical connector connected to a complementary mechanical
connector of the tail connecting portion of the second tethered
drone.
18. The tethered drone string of claim 17, wherein the mechanical
connector of the integrated electrical and mechanical connecting
assembly is threadingly connected to the complementary mechanical
connector of the tail connecting portion of the second tethered
drone.
19. The tethered drone string of claim 12, further comprising a
single battery positioned within the tail portion of the first
tethered drone, wherein the single battery provides a power supply
to each of the first tethered drone and the second tethered
drone.
20. The tethered drone string of claim 12, wherein the wellbore
tool is a wellbore data collection device connected to the tail
connecting portion via a complementary connection and configured
for connecting to the wireline, further wherein the wellbore data
collection device is the only removable component of the tethered
drone string after detonating the shaped charges, wherein the
wellbore data collection device is configured for being removed
from the wellbore by the wireline.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a national stage application of and
claims priority to Patent Cooperation Treaty (PCT) Application No.
PCT/M2019/000530 filed Mar. 29, 2019, which claims the benefit of
U.S. Provisional Patent Application No. 62/690,314 filed Jun. 26,
2018. The entire contents of each application listed above are
incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0002] Devices, systems, and methods for downhole delivery of one
or more wellbore tools in an oil or gas wellbore. More
specifically, devices, systems, and methods for improving
efficiency of downhole wellbore operations and minimizing debris in
the wellbore from such operations.
BACKGROUND OF THE DISCLOSURE
[0003] Hydraulic Fracturing (or, "fracking") is a commonly-used
method for extracting oil and gas from geological formations (i.e.,
"hydrocarbon formations") such as shale and tight-rock formations.
Fracking typically involves, among other things, drilling a
wellbore into a hydrocarbon formation; deploying a perforating gun
including shaped explosive charges in the wellbore via a wireline;
positioning the perforating gun within the wellbore at a desired
area; perforating the wellbore and the hydrocarbon formation by
detonating the shaped charges; pumping high hydraulic pressure
fracking fluid into the wellbore to force open perforations,
cracks, and imperfections in the hydrocarbon formation; delivering
a proppant material (such as sand or other hard, granular
materials) into the hydrocarbon formation to hold open the
perforations and cracks through which hydrocarbons flow out of the
hydrocarbon formation; and, collecting the liberated hydrocarbons
via the wellbore.
[0004] Perforating the wellbore and the hydrocarbon formations is
typically done using one more perforating guns. For example, as
shown in FIG. 1 and further described in U.S. Pat. No. 9,494,021
which is incorporated herein by reference in its entirety, a
conventional perforating gun string 100 may have two or more
perforating guns 110. Each perforating gun 110 may have a
substantially cylindrical carrier body 120 housing a charge carrier
130 including, among other things, one more shaped charges 140, a
detonating cord 150 for detonating the shaped charges 140, and a
conductive line 160 for relaying an electrical signal between
connected perforating guns 110. In such "enclosed" perforating guns
110, the carrier body 120 may use, for example, a variety of seals
and connections (unnumbered) to prevent the charge carrier 130,
shaped charges 140, and other internal components from being
exposed to harsh wellbore conditions which may include damaging
temperatures, pressures, fluids, corrosive materials, etc. Exposure
to such conditions may, for example, deactivate or destroy the
perforating gun 110 and associated components or cause premature
detonation.
[0005] Another known perforating gun type is an "exposed"
perforating gun 200, as shown in FIG. 2. The exposed perforating
gun 200 includes a charge carrier 220 with a plurality of
encapsulated shaped charges 210. The encapsulated shaped charges
210 are exposed to the surrounding environment. Thus, the
encapsulated shaped charges 210 may include a structure and/or
material that substantially isolates and seals the internal
components of the encapsulated shaped charge 210 from external
conditions. The exposed perforating gun 200 also includes a
conductive line 250 for relaying an electrical signal along the
length of the perforating gun 200 and a detonating cord 230 for
detonating the encapsulated shaped charges 210. The conductive line
250 and the detonating cord 230 are exposed to external conditions.
Thus, the conductive line 250 and the detonating cord 230 must be
configured to withstand the temperatures, pressures, and materials
that are found within a wellbore. In addition, as shown in FIG. 2,
the exposed perforating gun 200 includes a firing head 240 that
will initiate the detonating cord 230 upon activation. Multiple
exposed perforating guns 200 may also be connected in a gun
string.
[0006] Gun strings including multiple perforating guns help to
improve operational efficiency by allowing multiple perforating
intervals to be perforated during one wireline run into the
wellbore. The gun string may also include wellbore tools such as
one or more fracking plugs ("frac plug") or bridge plugs, tubing
cutters, etc. for downhole operations. For ease of reference in
this disclosure, a "gun string" may include any combination of
perforating guns and wellbore tools, which further encompasses
control devices and the like for use in downhole wellbore
operations. Each of the individual perforating guns and/or wellbore
tools in the string may have selective detonation/initiation
capability. By "selective" what is meant is that a detonator or
initiator assembly of an individual perforating gun or wellbore
tool is configured to receive one or more specific digital
sequence(s), which differs from a digital sequence that might be
used to arm and/or detonate another detonator or initiator assembly
in a different, adjacent perforating gun or tool. So, detonation of
the various perforating guns and/or tools does not necessarily have
to occur in a pre-programmed sequence. Any specific perforating gun
or tool can be selectively detonated/initiated. The
detonation/initiation of perforating guns typically occurs in a
bottom-up sequence, i.e., from the perforating gun (or wellbore
tool) that is farthest from the wireline to the perforating gun (or
wellbore tool) that is nearest, or connected to, the wireline.
Thus, in operation, the gun string is lowered or pumped down into
the wellbore to a desired location, one or more of the perforating
guns and/or tools is detonated/initiated, and the wireline is
retracted to the next desired location at which additional
perforating gun(s) and/or tool(s) are detonated/initiated. The
process repeats until all of the operations have been completed.
The wireline cable is then retracted to the surface of the wellbore
along with any components that have remained attached to the gun
string. Additional debris that remains in the wellbore may need to
be recovered as well.
[0007] Accordingly, current wellbore operations and system(s)
require substantial amounts of onsite personnel and equipment and
sometimes result in large residual debris post perforation in the
wellbore. Even with selective gun strings, a substantial amount of
time, equipment, and labor may be required to deploy the
perforating gun or wellbore tool string, position the perforating
gun or wellbore tool string at the desired location(s), and remove
residual debris post perforating. Further, current perforating
devices and systems may be made from materials that remain in the
wellbore after detonation of the shaped charges and leave a large
amount of debris that must be removed from the wellbore.
Accordingly, devices, systems, and methods that may reduce the
time, equipment, labor, and debris associated with downhole
operations would be beneficial.
BRIEF DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0008] In an aspect, an exemplary single-piece, self-contained
tethered drone comprises: a body portion; a head portion extending
from the body portion and including an integrated electrical and
mechanical connecting assembly; a tail portion extending from the
body portion in a direction opposite the head portion; a wellbore
data collection device housed within the drone and configured for
electrically connecting to a wireline; and at least one shaped
charge, wherein the tethered drone is formed at least in part from
a material that will substantially disintegrate upon detonating the
shaped charge, while the wellbore data collection device remains
intact and operable for delivering the collected data.
[0009] In another aspect, an exemplary single-piece, self-contained
tethered drone comprises: a body portion; a head portion extending
from the body portion; a tail portion extending from the body
portion in a direction opposite the head portion and configured for
connecting to a wireline, wherein the tail portion includes an
electrical transfer contact and circuitry for receiving an
electrical signal from a control unit via the wireline; a detonator
and optionally, a detonating cord coupled to the detonator, wherein
the circuitry transmits the electrical signal to the detonator; and
a plurality of shaped charges received in shaped charge apertures
in the body portion, wherein the shaped charge apertures are
respectively positioned adjacent to at least one of the detonator
and the detonating cord within an interior of the body portion,
wherein the tethered drone is formed at least in part from a
material that will substantially disintegrate upon detonating the
shaped charge.
[0010] In a further aspect, an exemplary tethered drone string for
downhole delivery of one or more wellbore tools comprises: a first
single-piece, self-contained tethered drone connected to a second
single-piece, self-contained tethered drone, the first tethered
drone and the second tethered drone respectively including a body
portion, a head portion, a tail portion, and at least one shaped
charge, wherein the head portion of the first tethered drone
extends from the body portion of the first tethered drone in a
direction towards the second tethered drone and includes an
integrated electrical and mechanical connecting assembly, the tail
portion of the first tethered drone extends from the body portion
of the first tethered drone in a direction opposite the head
portion and includes a tail connecting portion, wherein the tail
connecting portion of the first tethered drone is configured for at
least one of connecting to a wellbore tool and connecting to a
wireline, the tail portion of the second tethered drone includes a
tail connecting portion, wherein the tail connecting portion of the
second tethered drone is electrically and mechanically connected to
the integrated electrical and mechanical connecting assembly of the
first tethered drone, and the head portion of the first tethered
drone, alone, provides an electrical transfer and mechanical
coupling between the first tethered drone and the second tethered
drone via the integrated electrical and mechanical connecting
assembly; and a wellbore data collection device configured for at
least one of forming a connection between the first tethered drone
and the second tethered drone, forming a connection between at
least one of the first tethered drone and the second tethered drone
respectively and the wireline, and being housed within at least one
of the first tethered drone and the second tethered drone, wherein
the first tethered drone and the second tethered drone are formed
at least in part from a material that will substantially
disintegrate upon detonating the shaped charge, while the wellbore
data collection device remains intact and operable for delivering
the collected data.
[0011] For purposes of this disclosure, a "drone" is a
self-contained, autonomous or semi-autonomous vehicle for downhole
delivery of a wellbore tool. For purposes of this disclosure and
without limitation, "autonomous" means without a physical
connection or manual control and "semi-autonomous" means without
one of a physical connection or manual control.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more particular description will be rendered by reference
to specific embodiments thereof that are illustrated in the
appended drawings. Understanding that these drawings depict only
typical embodiments thereof and are not therefore to be considered
to be limiting of its scope, exemplary embodiments will be
described and explained with additional specificity and detail
through the use of the accompanying drawings in which:
[0013] FIG. 1 is a perspective view of a prior art perforating gun
string;
[0014] FIG. 2 is a perspective view of a prior art exposed
perforating gun;
[0015] FIG. 3A is a perspective view of a tethered drone according
to an exemplary embodiment;
[0016] FIG. 3B is another perspective view of the exemplary
embodiment shown in FIG. 3A;
[0017] FIG. 4 is a perspective view of a tethered drone string
according to an exemplary embodiment;
[0018] FIG. 5A is a lateral cross-sectional depiction of a
conductive detonating cord for use with the tethered drone
according to an exemplary embodiment;
[0019] FIG. 5B is a longitudinal cross-sectional depiction of the
conductive detonating cord of FIG. 5A;
[0020] FIG. 5C is a lateral cross-sectional depiction of another
conductive detonating cord for use with the tethered drone
according to an exemplary embodiment;
[0021] FIG. 5D is a longitudinal cross-sectional depiction of the
conductive detonating cord of FIG. 5C;
[0022] FIG. 6 illustrates a wellbore perforating system according
to an exemplary embodiment;
[0023] FIG. 7 is a cross-sectional view of a wireless detonator for
use with the tethered drone according to an exemplary embodiment;
and
[0024] FIG. 8 is a lateral cross-sectional depiction of a tethered
drone and arrangement of shaped charges according to an exemplary
embodiment.
[0025] Various features, aspects, and advantages of the embodiments
will become more apparent from the following detailed description,
along with the accompanying figures in which like numerals
represent like components throughout the figures and text. The
various described features are not necessarily drawn to scale but
are drawn to emphasize specific features relevant to some
embodiments.
[0026] The headings used herein are for organizational purposes
only and are not meant to limit the scope of the description or the
claims. To facilitate understanding, reference numerals have been
used, where possible, to designate like elements common to the
figures.
DETAILED DESCRIPTION
[0027] Reference will now be made in detail to various exemplary
embodiments. Each example is provided by way of explanation and is
not meant as a limitation and does not constitute a definition of
all possible embodiments.
[0028] With reference to FIGS. 3A and 3B, an exemplary embodiment
of a tethered drone 300 is shown. As described herein, the tethered
drone 300 may be conveyed via a wireline 620 (FIG. 6) into a
wellbore 670 (FIG. 6), for downhole delivery of one or more
wellbore tools such as, for example and without limitation, shaped
charges, a frac plug, a tubing cutter, and a wellbore data
collection system. The exemplary tethered drone 300 shown in FIGS.
3A and 3B includes a body portion 310 having a front end 311 and a
rear end 312. A head portion 320 extends from the front end 311 of
the body portion 310 and a tail portion 330 extends from the rear
end 312 of the body portion 310 in a direction opposite the head
portion 320. In an aspect, the head portion 320 includes a head
connecting portion 360 and the tail portion 330 includes a tail
connecting portion 370 for connecting a first tethered drone to a
second tethered drone in a tethered drone string 400, described
below with respect to FIG. 4, or to, for example and without
limitation, a wellbore tool or data collection system. The body
portion 310 includes a plurality of shaped charge apertures 313 and
open apertures 316 extending between an external surface 315 of the
body portion 310 and an interior 314 of the body portion 310. Each
of the plurality of shaped charge apertures 313 are configured for
receiving and retaining a shaped charge 340. The purpose and
configuration of the shaped charge apertures 313 and the open
apertures 316 will be further described below.
[0029] In the exemplary embodiment shown in FIGS. 3A and 3B, the
body portion 310, the head portion 320, and the tail portion 330
may be formed from a material that will substantially disintegrate
upon detonation of the shaped charges 340. In an exemplary
embodiment, the material may be an injection-molded plastic that
will substantially dissolve into a proppant when the shaped charges
340 are detonated. In the same or other embodiments, one or more
portions of the tethered drone 300 may be formed from a variety of
techniques and/or materials including, for example and without
limitation, injection molding, casting (e.g., plastic casting and
resin casting), metal casting, and 3D printing. Reference to the
exemplary embodiments including injection-molded plastics is thus
not limiting. A tethered drone 300 formed according to this
disclosure leaves a relatively small amount of debris in the
wellbore post perforation. In certain exemplary embodiments, one or
more of the body portion 310, the head portion 320, and the tail
portion 330 may be formed from plastic that is substantially
depleted of other components including metals. Substantially
depleted may mean, for example and without limitation, lacking
entirely or including only nominal or inconsequential amounts. In
other embodiments, the plastic may be combined with any other
materials consistent with this disclosure. For example, the
materials may include metal powders, glass beads or particles,
known proppant materials, and the like that may serve as a proppant
material when the shaped charges 340 are detonated. In addition,
the materials may include, for example, oil or hydrocarbon-based
materials that may combust and generate pressure when the shaped
charges 340 are detonated, synthetic materials potentially
including a fuel material and an oxidizer to generate heat and
pressure by an exothermic reaction, and materials that are
dissolvable in a hydraulic fracturing fluid.
[0030] In the exemplary disclosed embodiments, the body portion 310
is a unitary structure that may be formed from an injection-molded
material. In the same or other embodiments, at least two of the
body portion 310, the head portion 320, and the tail portion 330
are integrally formed from an injection-molded material. In other
embodiments, the body portion 310, the head portion 320, and the
tail portion 330 may constitute modular components or
connections.
[0031] As shown in FIGS. 3A and 3B, each of the body portion 310,
the head portion 320, and the tail portion 330 is substantially
cylindrically-shaped. The head portion 320 and the tail portion 330
each have a maximum diameter that is greater than a maximum
diameter of the body portion 310, and at least a portion of each of
the head portion 320 and the tail portion 330 extends beyond the
maximum diameter of the body portion 310. The exemplary disclosed
configuration may help protect the body portion 310, the shaped
charges 340, and the internal components of the body portion 310
from collisions and fluid pressures during the descent of the
tethered drone 300 into the wellbore 670. For example, the larger
diameter of the head portion 320 and tail portion 330 may block the
body portion 310 from collisions and force fluid pressure away from
the body portion 310. Each of the head portion 320 and the tail
portion 330 also includes fins 373 configured for reducing friction
during the descent of the tethered drone 300 into the wellbore
670.
[0032] With continuing reference to FIGS. 3A and 3B, each of the
plurality of shaped charge apertures 313 in the body portion 310
may receive and retain a portion of a shaped charge 340 in a
corresponding hollow portion (unnumbered) of the interior 314 of
the body portion 310. Another portion of the shaped charge 340
remains exposed to the surrounding environment. Thus, the body
portion 310 may be considered in some respects as an exposed charge
carrier, and the shaped charges 340 may be encapsulated, pressure
sealed shaped charges having a lid or cap. The plurality of open
apertures 316 may be configured for, among other things, reducing
friction against the body portion 310 as the tethered drone 310 is
conveyed into a wellbore 670 and/or for enhancing the
collapse/disintegration properties of the body portion 310 when the
shaped charges 340 are detonated.
[0033] The interior 314 of the body portion 310 may have hollow
regions and non-hollow regions. As discussed above, the shaped
charge apertures 313 receive and retain a portion of the shaped
charge 340 in a hollow portion of the interior 314 of the body
portion 310. Other regions of the interior 314 may be formed as
non-hollow or may include additional internal components of the
tethered drone 300 as applications dictate. While the shaped charge
apertures 313 (and correspondingly, the shaped charges 340) are
shown in a typical helical arrangement about the body portion 310
in the exemplary embodiment shown in FIGS. 3A and 3B, the
disclosure is not so limited and it is contemplated that any
arrangement of one or more shaped charges 340 may be accommodated,
within the spirit and scope of this disclosure, by the tethered
drone 300. For example, a single shaped charge aperture or a
plurality of shaped charge apertures for respectively receiving a
shaped charge may be positioned at any phasing (i.e.,
circumferential angle) on the body portion, and a plurality of
shaped charge apertures may be included, arranged, and aligned in
any number of ways. For example, and without limitation, the shaped
charge apertures 313 may be arranged, with respect to the body
portion, along a single longitudinal axis, within a single radial
plane, in a staggered or random configuration, spaced apart along a
length of the body portion, pointing in opposite directions, or the
like. An embodiment of a tethered drone 800 with shaped charges 840
in a planar radial arrangement according to this disclosure is
shown in FIG. 8 (discussed below), which is a lateral
cross-sectional view of a body portion 810 of such embodiment at a
line corresponding to line X shown in FIG. 3A, although not limited
thereto.
[0034] The body portion 310 of the exemplary tethered drone 300
also houses the detonating cord 350 for detonating the shaped
charges 340 and relaying ballistic energy along the length of the
tethered drone 300. In the exemplary embodiment shown in FIGS. 3A
and 3B, the detonating cord 350 is housed within the interior 314
of the body portion and is exposed to the surrounding environment
through the open apertures 316. Accordingly, the detonating cord
350 is configured for withstanding the conditions and materials
within a wellbore, without becoming destroyed or inoperable, or
detonating prematurely. Such exposed detonating cords are
known.
[0035] In some embodiments, and depending on the arrangement of the
shaped charge apertures 313 and shaped charges 340, the detonating
cord 350 may be arranged in a complementary manner to ensure that
the detonating cord 350 is in sufficient contact or proximity to
the shaped charges 340, for detonating the shaped charges 340.
[0036] In an aspect, the body portion 310 of the tethered drone 300
also houses a conductive line (not shown) for relaying an
electrical signal along the length of the tethered drone 300, as
discussed further below. In the exemplary embodiment shown in FIGS.
3A and 3B, the detonating cord 350 is a conductive detonating cord
and includes the conductive line. In other embodiments, the
conductive line and the detonating cord 350 may be separate
components. An exemplary conductive detonating cord 350 according
to the exemplary embodiments is discussed and shown with respect to
FIGS. 5A-5D and described in U.S. patent application Ser. No.
16/152,933 filed Oct. 5, 2018, which is incorporated herein by
reference in its entirety. The conductive detonating cord 350 is
configured for being in electrical communication at one end with an
electrical transfer contact 371a in the tail connecting portion
370, and at an opposite end with an electrical transfer contact
such as a pin contact 365 in the head connecting portion 360. In
the exemplary embodiment shown in FIG. 3B, the electrical transfer
contact 371a may be an electrical contact or "line in" on a
detonator 371, as discussed further below. In such case, the
conductive detonating cord 350 and/or conductive component of the
conductive detonating cord 350 (or, the conductive line in
embodiments where the conductive line and detonating cord are
separate components) may be in electrical communication with the
electrical transfer contact 371a via a "line out" on the detonator
371. In the same or other embodiments, electrical transfer contact
371a may be at least a part of an electrical relay to a line in of
a detonator and/or a conductive line or conductive detonating cord.
The conductive detonating cord 350 in the exemplary embodiments
transfers an electrical signal along the length of the tethered
drone from the electrical transfer contact 371a of the tail
connecting portion 370 to the pin contact 365 in the head
connecting portion 360. The electrical signal may be provided to
the electrical transfer contact 371a of the tail connecting portion
370 by the wireline 620 or an upstream tethered drone that is
connected to the tail connecting portion 370 in a tethered drone
string 400, as described below with respect to FIG. 4. The
electrical signal may provide, among other things, a selective
detonation signal for the tethered drone 300. For purposes of this
disclosure, "upstream" in a gun string means in a direction towards
the wireline 620 and "downstream" means in a direction away from
the wireline.
[0037] The tail connecting portion 370 in the exemplary embodiments
includes the detonator 371, an igniter, or an initiator
(collectively, "detonator") 371 for activating the conductive
detonating cord 350 upon receiving the selective detonation signal
or communicating downline through the electrically conductive cord.
A detonator bulkhead seal 372 may substantially isolate the
detonator or a relay/transition from the detonator 371 to the
detonating cord 350 from exposure to the wellbore fluid, including
the associated high temperatures, pressures, and potentially
corrosive components.
[0038] In an exemplary embodiment, the detonator 371 may be a
wireless detonator assembly as shown in FIG. 7 and further
described in U.S. Pat. No. 9,581,422 which is incorporated herein
by reference in its entirety. In an exemplary wireless detonator
assembly 710 shown in FIG. 7, a detonator shell 712 is shaped as a
hollow cylinder and houses at least a detonator head plug 714, a
fuse head 715, an electronic circuit board 716, and explosive
components 730. The electronic circuit board 716 is connected to
the fuse head 715 and is configured for allowing selective
detonation of the detonator assembly 710. The electronic circuit
board 716 is configured to wirelessly and selectively receive an
ignition signal I, (typically a digital code uniquely configured
for a specific detonator), to fire a perforating gun.
[0039] With continuing reference to FIG. 7, a detonator head 718
extends from one end of the detonator shell 712 and includes more
than one electrical contacting component including an electrically
contactable line-in portion 720 and an electrically contactable
line-out portion 722, according to an aspect. In an exemplary
embodiment of the tethered drone 300 including the detonator
assembly 710 shown in FIG. 7, line-in portion 720 may serve as the
electrical transfer contact 371a. According to one aspect, the
detonator assembly 710 may also include an electrically contactable
ground portion 713. The detonator head 718 may be disk-shaped. In
an aspect, at least a portion of the detonator shell 712 is
configured as the ground portion 713. The detonator head 718 also
includes an insulator 724, which is positioned between the line-in
portion 720 and the line-out portion 722. The insulator 724
functions to electrically isolate the line-in portion 720 from the
line-out portion 722. Insulation may also be positioned between
other lines of the detonator head 718. It is possible for all of
the contacts to be configured as part of the detonator head 718
(not shown), as found, for instance, in a banana connector used in
a headphone wire assembly in which the contacts are stacked
longitudinally along a central axis of the connector, with the
insulating portion situated between them.
[0040] In the exemplary wireless detonator assembly 710, a
capacitor 717 is positioned or otherwise assembled as part of the
electronic circuit board 716. The capacitor 717 is configured to be
discharged to initiate the detonator assembly 710 upon receipt of a
digital firing sequence via the ignition signal I, the ignition
signal being electrically relayed directly through the line-in
portion 720 and the line-out portion 722 of the detonator head 718.
The fuse head 715 initiates the explosive load 730. In a typical
arrangement, a first digital code is transmitted down-hole to and
received by the electronic circuit board 716. Once it is confirmed
that the first digital code is the correct code for that specific
detonator assembly, an electronic gate is closed and the capacitor
717 is charged. Then, as a safety feature, a second digital code is
transmitted to and received by the electronic circuit board 716.
The second digital code, which is also confirmed as the proper code
for the particular detonator, closes a second gate, which in turn
discharges the capacitor 717 via the fuse head 715 to initiate the
detonation.
[0041] The exemplary detonator assembly 710 according to an aspect
can be either an electric or an electronic detonator. In an
electric detonator, a direct wire from the surface is electrically
contactingly connected to the detonator assembly 710 and power is
increased to directly initiate the fuse head 715. In an electronic
detonator assembly, circuitry of the electronic circuit board 716
within the detonator assembly is used to initiate the fuse head
715.
[0042] With reference again now to FIGS. 3A and 3B and the
exemplary tethered drone 300, the tail connecting portion 370 may
further include an onboard computer or other circuitry (not shown)
for, among other things, receiving the selective detonation signal
and other commands from a control unit 630 (see FIG. 6) or
capturing information regarding the wellbore such as geometry,
distance, temperature, pressure, fluid properties, etc. The
tethered drone 300 and associated components may be powered by one
or more of a power source conveyed by the wireline 620, one or more
batteries in each tethered drone 300, or one or more batteries at
the top of a gun string 400 that relays power via the conductive
line to each tethered drone 300 in the gun string 400. In some
embodiments, the power source may include a capacitor, instead of a
single battery pack, charged on surface before the drone is
deployed into the wellbore and configured for providing power to
the tethered drone and associated components, and/or a data
collection device and other wellbore tool(s). Such capacitor may be
charged on surface by a power supply configured for electrically
connecting to the capacitor, either directly or via one or more
electrical relays, and providing a sufficient electric current to
load the capacitor. The power supply may take any form consistent
with this disclosure. As a safety measure, the wired power source
and/or battery(-ies) or other power sources may not be activated
until, for example and without limitation, the tethered drone 300
is deployed in the wellbore 670 to a particular distance or for a
particular amount of time. Thus, the detonator 371 may not be armed
until the tethered drone 300 reaches a safe position and the
power/battery(-ies) activate.
[0043] The head connecting portion 360 is configured for connecting
to and being in electrical contact with a downstream tethered drone
or wellbore tool in a tethered drone string 400 as described with
respect to FIG. 4. In the exemplary embodiment shown in FIGS. 3A
and 3B, the head connecting portion 360 and the tail connecting
portion 370 each include a threaded portion 361, 374 that is
respectively configured for being threadingly connected to a
complimentary connecting portion on an adjacent tethered drone. In
other embodiments, the connection between the head connecting
portion 360 and the tail connecting portion 370 may be by other
known devices or techniques that are consistent with the scope of
this disclosure. Additional components such as a wellbore tool or a
data collection system with a complimentary threaded connection (or
other connection) may also be connected to the tethered drone 300
via the head connecting portion 360 and/or the tail connecting
portion 370. For purposes of this disclosure, the exemplary
disclosed connections between adjacent tethered drones is
representative of connections between a tethered drone 300 and such
additional components.
[0044] According to an exemplary embodiment, the pin contact 365 of
the head connecting portion 360 is configured for being in
electrical contact with the electrical transfer contact 371a of the
tail connecting portion 370 of an adjacent tethered drone when the
head connecting portion 360 is connected to the tail connecting
portion 370 of the adjacent tethered drone. The pin contact 365 is
configured to transfer the electrical signal from the conductive
line or conductive detonating cord 350 to the electrical transfer
contact 371a of the tail connecting portion 370 of the adjacent
tethered drone such that the electrical signal may be provided to,
e.g., the detonator 371 or other component(s) of the adjacent
tethered drone and/or a conductive line or conductive detonating
cord of the adjacent tethered drone. In an aspect, the pin contact
365 may, among other things, also transfer control information,
instructions, data, or power from a control unit 630, wireline 620,
and/or battery (not illustrated) to the electrical transfer contact
371a or other onboard computer/circuitry of the tail connecting
portion 370 of the adjacent tethered drone. In another aspect, the
pin contact 365 may be a spring-loaded pin contact 365 that is
biased towards the adjacent tethered drone to maintain electrical
contact with the electrical transfer contact 371a of the tail
connecting portion 370 of the adjacent tethered drone. The
respective electrical transfer contacts of the head connecting
portion 360 and the tail connecting portion 370 are not limited
according to this disclosure. The respective electrical transfer
contacts of the head connecting portion 360 and the tail connecting
portion 370 may take any form or configuration consistent with this
disclosure--for example, configured for being in electrical contact
when the head connecting portion 360 of a first tethered drone 300
is connected to the tail connecting portion 370 of a second
tethered drone 300 and for relaying the electrical signal from the
conductive detonating cord 350 of the first tethered drone 300 to,
e.g., the detonator 371 or other component(s) of the second
tethered drone 300.
[0045] With continuing reference to FIGS. 3A and 3B, the exemplary
tethered drone 300 may also include a blast barrier 380 positioned
between at least a portion of the head portion 320 of the tethered
drone 300 and the tail portion (330) of a downstream tethered drone
that is attached to the head connecting portion 360 of the tethered
drone 300. The blast barrier 380 may be configured for shielding
the head portion 320 of the tethered drone 300 from detonation,
disintegration, and debris of the downstream tethered drone and
preventing destruction and/or disintegration of the head portion
320 of the tethered drone 300 as a result of the downstream
detonation. The blast barrier 380 may generally be any shape
consistent with this disclosure and may be formed from a variety of
materials consistent with this disclosure such as, for example and
without limitation, metals and plastics and combinations of those
materials. In the same or other embodiments, the head portion 320
of the tethered drone 300 may be formed from a material such as
metals, plastics, or combinations of those materials, and/or have a
material structure or size configured for resisting disintegration
under the force and heat of a downstream detonation.
[0046] With reference now to FIG. 4, an exemplary tethered drone
string 400 is shown. Two or more tethered drones 401, 402 may be
connected to form a tethered drone string 400. Each of a first
tethered drone 401 and a second tethered drone 402 is an exemplary
tethered drone as described above with respect to FIGS. 3A and 3B
and includes a body portion 410, 411, a head portion 420, 421
having a head connecting portion 460, and a tail portion 430, 431
having a tail connecting portion 470. Each of the first tethered
drone 401 and the second tethered drone 402 carries shaped charges
440, 441 in the body portion 410, 411 as discussed with respect to
FIGS. 3A and 3B. The head connecting portion 460 (not visible in
the illustration of FIG. 4) of the first tethered drone 401 is
connected to the tail connecting portion 470 (not visible in the
illustration of FIG. 4) of the second tethered drone 402. In the
same or other embodiments, the head connecting portion 460 or the
tail connecting portion 470 of a tethered drone 401, 402 in a drone
string 400 may be connected to, for example and without limitation,
a wellbore tool or a data collection system.
[0047] The head connecting portion 420, 421 of each of the first
tethered drone 401 and the second tethered drone 402 in the
exemplary embodiment shown in FIG. 4 includes, among other things,
an electrical transfer contact such as the pin contact 365 (not
visible in FIG. 4) as discussed with respect to FIGS. 3A and 3B.
The tail connecting portion 430, 431 of each of the first tethered
drone 401 and the second tethered drone 402 includes, among other
things, a detonator 471 and an electrical transfer contact 471a as
also discussed with respect to FIGS. 3A and 3B. Accordingly, a
conductive detonating cord 450, 451 may relay ballistic energy and
an electrical signal along a length of the respective tethered
drones 401, 402 from the electrical transfer contact 471a (in an
embodiment, via the line out connection of a detonator assembly or
an appropriate relay) of the tail connecting portion 470 to the pin
contact 365 in the same manner as discussed with respect to the
exemplary embodiment shown in FIGS. 3A and 3B. In the exemplary
embodiment shown in FIG. 4, the pin contact 365 of the first
tethered drone 401 is in electrical contact with the electrical
transfer contact 471a of the tail connecting portion 470 of the
second tethered drone 402.
[0048] In use, the first tethered drone 401 may be the topmost
tethered drone in the tethered drone string 400; i.e., the tethered
drone that is connected to the wireline 620 or, for example and
without limitation, a wellbore tool, a firing head, an electronic
control component, one or more batteries, or the like that is
connected between the wireline 620 and the first tethered drone
401. In any such embodiment, an electrical transfer contact of the
wireline 620 or other component is configured for being in
electrical contact with the electrical transfer contact 471a of the
tail connecting portion 470 of the first drone 401. In an aspect,
an electrical signal constituting a selective detonation signal may
be sent from the control unit 630 at a surface 601 of the wellbore
670 and conveyed via the wireline 620 to the electrical transfer
contact 471a of the tail connecting portion 470 of the first
tethered drone 401. The selective detonation signal may be
configured to activate the detonator 471 of a downstream tethered
drone 402 or wellbore tool. Thus, the detonator 471 of the first
tethered drone 401 will not be activated by the selective
detonation signal. The conductive detonating cord 450 of the first
tethered drone 401 will relay the selective detonation signal from
the electrical transfer contact 471a of the tail connecting portion
470 of the first tethered drone 401 to the pin contact 365 of the
first tethered drone 401. The pin contact 365 of the first tethered
drone 401 will transfer the selective detonation signal to the
electrical transfer contact 471a of the tail connecting portion 470
of the second tethered drone 402. If the selective detonation
signal corresponds to the second tethered drone 402, the detonator
471 of the second tethered drone 402 will activate and
ballistically initiate the conductive detonating cord 451 to
detonate the shaped charges 441 that the second tethered drone 402
carries. The process will repeat for each tethered drone and/or
wellbore tool in the tethered drone string 400. According to the
exemplary embodiment of the tethered drone 300, each tethered drone
401, 402 in the drone string 400 may be formed from an
injection-molded plastic material that will substantially
disintegrate and/or dissolve into a proppant upon detonation of the
shaped charges 440, 441, thereby reducing the amount of debris
generated by successive detonations of the tethered drones 401,
402.
[0049] Notably, the configuration of the tethered drone string 400
and, in particular, the conductive line (for example, in the
conductive detonating cord 450, 451 of the exemplary embodiments)
allows a single power source, such as a single battery at the top
of the tethered drone string 400, to provide power to each tethered
drone 401, 402 and/or wellbore tool in the tethered drone string
400. The power may be relayed between each tethered drone 401, 402
and/or wellbore tool via the conductive detonating cords 450, 451
in the same manner as, e.g., the selective detonation signal.
[0050] With reference now to FIGS. 5A-5D, FIGS. 5A and 5B
respectively show a lateral cross-section and a longitudinal
cross-section of a first exemplary embodiment of a conductive
detonating cord 10 for use with the exemplary tethered drone 300,
and FIGS. 5C and 5D respectively show a lateral cross-section and a
longitudinal cross-section of a second exemplary embodiment of a
conductive detonating cord 10 for use with the exemplary tethered
drone 300. The conductive detonating cord 10 may be a flexible
structure that allows the conductive detonating cord 10 to be bent
or wrapped around structures. According to an aspect, the
conductive detonating cord 10 may include a protective structure or
sheath 16 that prevents the flow of an extraneous or stray electric
current through an explosive layer 14 within the conductive
detonating cord 10. The explosive layer 14 may include an
insensitive secondary explosive (i.e., an explosive that is less
sensitive to electrostatic discharge (ESD), friction and impact
energy within the detonating cord, as compared to a primary
explosive). According to an aspect, the explosive layer 14 includes
at least one of pentaerythritol tetranitrate (PETN),
cyclotrimethylenetrinitramine (RDX),
octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine/cyclotetramethylene-tetr-
anitramine (HMX), Hexanitrostilbene (HNS),
2,6-Bis(picrylamino)-3,5-dinitropyridine (PYX), and
nonanitroterphenyl (NONA). The type of material selected to form
the explosive layer 14 may be based at least in part on the
temperature exposure, radial output and detonation velocity of the
material/explosive. In an embodiment, the explosive layer 14
includes a mixture of explosive materials, such as, HNS and NONA.
As would be understood by one of ordinary skill in the art, the
explosive layer 14 may include compressed explosive materials or
compressed explosive powder. The explosive layer 14 may include
constituents to improve the flowability of the explosive powder
during the manufacturing process. Such constituents may include
various dry lubricants, such as, plasticizers, graphite, and
wax.
[0051] The conductive detonating cord 10 further includes an
electrically conductive layer 12. The electrically conductive layer
12 is configured to transfer a communication signal along a length
L of the conductive detonating cord 10. The communication signal
may be a telemetry signal. According to an aspect, the
communication signal includes at least one of a signal to check and
count for detonators in a perforating gun string assembly, address
and switch to certain detonators, charge capacitors, send a signal
to initiate a detonator communicably connected to the conductive
detonating cord 10, and various other functions as described in
this disclosure. The integration of the electrically conductive
layer 12 in the conductive detonating cord 10 helps to omit
conductive lines as a separate component.
[0052] According to an aspect, the electrically conductive layer 12
extends around the explosive layer 14 in a spaced apart
configuration. An insulating layer 18 (FIGS. 5C and 5D) may be
sandwiched between the explosive layer 14 and the electrically
conductive layer 12. The electrically conductive layer 12 of the
detonating cord 10 may include a plurality of electrically
conductive threads/fibers spun or wrapped around the insulating
layer 18, or an electrically conductive sheath/pre-formed
electrically conductive sheath 13 in a covering relationship with
the insulating layer 18. According to an aspect, the electrically
conductive sheath 13 comprises layers of electrically conductive
woven threads/fibers that are pre-formed into a desired shape that
allows the electrically conductive sheath to be easily and
efficiently placed or arranged over the insulating layer 18. The
layers of electrically conductive woven threads may be configured
in a type of crisscross or overlapping pattern in order to minimize
the effective distance the electrical signal must travel when it
traverses through the conductive detonating cord 10. This
arrangement of the threads helps to reduce the electrical
resistance (Ohm/ft or Ohm/m) of the conductive detonating cord 10.
The electrically conductive threads and the electrically conductive
woven threads may include metal fibers or may be coated with a
metal, each metal fiber or metal coating having a defined
resistance value (Ohm/ft or Ohm/m). It is contemplated that longer
gun strings (i.e., more perforating guns in a single string) may be
formed using perforating guns that include the conductive
detonating cord 10.
[0053] FIGS. 5C and 5D illustrate the conductive detonating cord 10
including the insulating layer 18. The insulating layer 18 is
disposed/positioned between the explosive layer 14 and the
electrically conductive layer 12. As illustrated in FIG. 5D, for
example, the insulating layer 18 may extend along the length L of
the conductive detonating cord 10. In other embodiments, the
insulating layer 18 may only extend along a portion of the length L
of the detonating cord and the explosive layer 14 may be adjacent
to the electrically conductive layer 12. The insulating layer 18
may be formed of any nonconductive material. According to an
aspect, the insulating layer 18 may include at least one of a
plurality of non-conductive aramide threads, a polymer, such as
fluorethylenpropylene (FEP), polyamide (PA),
polyethylenterephthalate (PET), or polyvinylidenfluoride (PVDF),
and a coloring additive.
[0054] The conductive detonating cord 10 may include a layer of
material along its external surface to impart additional strength
and protection to the structure of the conductive detonating cord
10. FIGS. 5A-5D each illustrate a jacket/outer protective jacket 16
externally positioned on the conductive detonating cord 10.
According to an aspect, the jacket 16 is formed of at least one
layer of woven threads. The jacket 16 may be formed from a
nonconductive polymer material, such as FEP, PA, PET, and PVDF.
According to an aspect, the jacket 16 is formed of at least one
layer of non-conductive woven threads and covered by a sheath
formed from a plastic, composite or lead.
[0055] As illustrated in FIGS. 5A and 5C, the jacket 16 extends
around/surrounds/encases the electrically conductive layer
12/electrically conductive sheath 13, the insulating layer 18, and
the explosive layer 14. The jacket 16 extends along the length L of
the conductive detonating cord 10, and may be impervious to at
least one of sour gas (H.sub.2S), water, drilling fluid, and
electrical current.
[0056] According to an aspect, electric pulses, varying or
alternating current or constant/direct current may be induced into
or retrieved from the electrically conductive layer 12/electrically
conductive sheath 13 of the conductive detonating cord 10. The
conductive detonating cord 10 includes contacts (not shown) that
are configured to input a communication signal at a first end of
the conductive detonating cord 10, and output the communication
signal at a second end of the conductive detonating cord 10.
According to an aspect, the contacts may include a metal, such as
aluminum, brass, copper, stainless steel or galvanized steel
(including zinc). In order to facilitate the communication of the
communication signal, the contacts may at least partially be
embedded into the conductive detonating cord 10. The contacts may
be coupled to or otherwise secured to the conductive detonating
cord 10. According to an aspect, the contacts are crimped onto the
detonating cord 10, in such a way that the contacts pierce through
the protective outer jacket 16 of the conductive detonating cord 10
to engage the electrically conductive layer 12 or the conductive
sheath 13. In use with an exemplary tethered drone 300, the
contacts are configured without limitation for being in electrical
communication with the electrical transfer contact 371a and the pin
contact 365.
[0057] With reference now to FIG. 6, an exemplary wellbore
operation site and system is illustrated. The site includes a
hydrocarbon formation 602 under the surface 601 of the
ground/wellbore 670. The wellbore 670 extends into the hydrocarbon
formation 602 in both vertical and horizontal directions. A
wellbore casing or tubing 660 lines the inside of the wellbore 670.
One or more tethered drones 300 according to the exemplary
embodiment shown in FIGS. 3A and 3B are conveyed downhole in the
wellbore 670 via the wireline 620 in an interior 661 of the
tubing/casing 660. A wireline spool 610 at the surface 601 of the
wellbore 670 feeds the wireline 620 into the wellbore 670. Upon
reaching a desired position within the wellbore 670, the shaped
charges 340 of the tethered drone 300 are detonated 640 and
perforate 650 the tubing/casing 660 and the hydrocarbon formation
602. The tethered drone(s) 300 are controlled and/or powered by the
control unit 630 at the surface 601 of the wellbore 670. In an
exemplary embodiment, the control unit 630 may communicate
unidirectionally with the tethered drone via a relay on the
wireline 620. In other embodiments, the control unit 630 and the
tethered drone may communicate bi-directionally and/or via a
wireless link.
[0058] With reference now to FIG. 8, the lateral cross-sectional
view of the exemplary tethered drone 800 including shaped charges
840 arranged in a planar radial configuration, as discussed with
respect to FIG. 3A, is shown. The lateral cross-sectional view is
taken through the body portion in the direction indicated by line X
in FIG. 3A, although not limited to the position or configuration
shown in FIG. 3A. The lateral cross-sectional view of the exemplary
tethered drone shown in FIG. 8 bisects three shaped charges 840
arranged in the same radial plane with respect to the body portion
810 and spaced apart by about a 120-degree phasing around the body
portion 810. As previously discussed, the shaped charges 840 are
respectively received and retained in shaped charge apertures 813
at least in part within an interior 814 of the body portion 810. In
the exemplary configuration shown in FIG. 8, a detonator 871 for
detonating the shaped charges 840 is positioned within the interior
814 of the body portion 810 and adjacent to the shaped charges 840.
The shaped charges 840 extend radially outwardly from the detonator
871. In some embodiments, the shaped charges 840 may be adjacent to
and extending radially outwardly from a detonating cord for
detonating the shaped charges 840, depending on, e.g., a desired
configuration for particular applications. As previously discussed,
the planar radial configuration of the shaped charges 840 in the
tethered drone 800 embodiment shown in FIG. 8 is not limiting with
respect to the embodiments contemplated by this disclosure, nor is
the placement or position of a detonator, a detonating cord, or
other components of a tethered drone.
[0059] The present disclosure, in various embodiments,
configurations and aspects, includes components, methods,
processes, systems and/or apparatus substantially developed as
depicted and described herein, including various embodiments,
sub-combinations, and subsets thereof. Those of skill in the art
will understand how to make and use the present disclosure after
understanding the present disclosure. The present disclosure, in
various embodiments, configurations and aspects, includes providing
devices and processes in the absence of items not depicted and/or
described herein or in various embodiments, configurations, or
aspects hereof, including in the absence of such items as may have
been used in previous devices or processes, e.g., for improving
performance, achieving ease and/or reducing cost of
implementation.
[0060] The phrases "at least one", "one or more", and "and/or" are
open-ended expressions that are both conjunctive and disjunctive in
operation. For example, each of the expressions "at least one of A,
B and C", "at least one of A, B, or C", "one or more of A, B, and
C", "one or more of A, B, or C" and "A, B, and/or C" means A alone,
B alone, C alone, A and B together, A and C together, B and C
together, or A, B and C together.
[0061] In this specification and the claims that follow, reference
will be made to a number of terms that have the following meanings.
The terms "a" (or "an") and "the" refer to one or more of that
entity, thereby including plural referents unless the context
clearly dictates otherwise. As such, the terms "a" (or "an"), "one
or more" and "at least one" can be used interchangeably herein.
Furthermore, references to "one embodiment", "some embodiments",
"an embodiment" and the like are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Approximating language, as used
herein throughout the specification and claims, may be applied to
modify any quantitative representation that could permissibly vary
without resulting in a change in the basic function to which it is
related. Accordingly, a value modified by a term such as "about" is
not to be limited to the precise value specified. In some
instances, the approximating language may correspond to the
precision of an instrument for measuring the value. Terms such as
"first," "second," "upper," "lower" etc. are used to identify one
element from another, and unless otherwise specified are not meant
to refer to a particular order or number of elements.
[0062] As used herein, the terms "may" and "may be" indicate a
possibility of an occurrence within a set of circumstances; a
possession of a specified property, characteristic or function;
and/or qualify another verb by expressing one or more of an
ability, capability, or possibility associated with the qualified
verb. Accordingly, usage of "may" and "may be" indicates that a
modified term is apparently appropriate, capable, or suitable for
an indicated capacity, function, or usage, while taking into
account that in some circumstances the modified term may sometimes
not be appropriate, capable, or suitable. For example, in some
circumstances an event or capacity can be expected, while in other
circumstances the event or capacity cannot occur--this distinction
is captured by the terms "may" and "may be."
[0063] As used in the claims, the word "comprises" and its
grammatical variants logically also subtend and include phrases of
varying and differing extent such as for example, but not limited
thereto, "consisting essentially of" and "consisting of." Where
necessary, ranges have been supplied, and those ranges are
inclusive of all sub-ranges therebetween. It is to be expected that
variations in these ranges will suggest themselves to a
practitioner having ordinary skill in the art and, where not
already dedicated to the public, the appended claims should cover
those variations.
[0064] The terms "determine", "calculate" and "compute," and
variations thereof, as used herein, are used interchangeably and
include any type of methodology, process, mathematical operation or
technique.
[0065] The foregoing discussion of the present disclosure has been
presented for purposes of illustration and description. The
foregoing is not intended to limit the present disclosure to the
form or forms disclosed herein. In the foregoing Detailed
Description for example, various features of the present disclosure
are grouped together in one or more embodiments, configurations, or
aspects for the purpose of streamlining the disclosure. The
features of the embodiments, configurations, or aspects of the
present disclosure may be combined in alternate embodiments,
configurations, or aspects other than those discussed above. This
method of disclosure is not to be interpreted as reflecting an
intention that the present disclosure requires more features than
are expressly recited in each claim. Rather, as the following
claims reflect, the claimed features lie in less than all features
of a single foregoing disclosed embodiment, configuration, or
aspect. Thus, the following claims are hereby incorporated into
this Detailed Description, with each claim standing on its own as a
separate embodiment of the present disclosure.
[0066] Advances in science and technology may make substitutions
possible that are not now contemplated by reason of the imprecision
of language; these variations should be covered by the appended
claims. This written description uses examples to disclose the
method, machine and computer-readable medium, including the best
mode, and also to enable any person of ordinary skill in the art to
practice these, including making and using any devices or systems
and performing any incorporated methods. The patentable scope
thereof is defined by the claims, and may include other examples
that occur to those of ordinary skill in the art. Such other
examples are intended to be within the scope of the claims if, for
example, they have structural elements that do not differ from the
literal language of the claims, or if they include structural
elements with insubstantial differences from the literal language
of the claims.
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