U.S. patent application number 15/622662 was filed with the patent office on 2017-12-14 for systems and methods for multi-zone power and communications.
The applicant listed for this patent is Chevron U.S.A. Inc.. Invention is credited to David William Beck, Melvin Clark Thompson.
Application Number | 20170356274 15/622662 |
Document ID | / |
Family ID | 60573702 |
Filed Date | 2017-12-14 |
United States Patent
Application |
20170356274 |
Kind Code |
A1 |
Thompson; Melvin Clark ; et
al. |
December 14, 2017 |
Systems And Methods For Multi-Zone Power And Communications
Abstract
A system, method and device may be used to provide power and
monitor conditions in a borehole. Well tubing and casing act as a
conductive pair for delivering power wirelessly to isolated zones
defined between packer elements. Data signals are similarly
transmitted. The packer elements include magnetic toroidal cores
for power and signal transmission via inductively coupling.
Inventors: |
Thompson; Melvin Clark; (Los
Alamos, NM) ; Beck; David William; (Santa Fe,
NM) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chevron U.S.A. Inc. |
San Ramon |
CA |
US |
|
|
Family ID: |
60573702 |
Appl. No.: |
15/622662 |
Filed: |
June 14, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62349769 |
Jun 14, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 47/12 20130101;
E21B 43/14 20130101; E21B 17/003 20130101; E21B 17/028 20130101;
E21B 33/12 20130101; E21B 41/00 20130101 |
International
Class: |
E21B 41/00 20060101
E21B041/00; E21B 43/14 20060101 E21B043/14; E21B 33/129 20060101
E21B033/129; E21B 33/12 20060101 E21B033/12 |
Claims
1. A packer assembly for disposal within a subterranean wellbore
lined by a casing, the packer assembly comprising: a packer
comprising an upper end, a lower end, and a feedthrough that
traverses the packer from the upper end to the lower end, wherein
the upper end is configured to couple to a first tubing string,
wherein the lower end is configured to couple to a second tubing
string; a first core disposed around the second tubing string
adjacent to the lower end of the packer; and an electrical wire
disposed within the feedthrough of the packer, wherein the
electrical wire has a proximal end and a distal end wrapped around
the first core, wherein the proximal end of the electrical wire is
configured to receive a first power from a power source disposed
above the upper end of the packer, wherein the distal end of the
electrical wire is configured to use the first power to induce a
second power in the first core, wherein the second power in the
first core generates a first current that flows on the second
tubing string away from the first core.
2. The packer assembly of claim 1, wherein the power source
comprises a second core disposed around the first tubing string
adjacent to the upper end of the packer, wherein the proximal end
of the electrical wire is wrapped around the second core.
3. The packer assembly of claim 2, wherein the packer, the first
core, the second core, and the electrical wire form a single
integral piece.
4. The packer assembly of claim 2, wherein the second core is
configured to receive a second current from a third core of an
additional packer assembly, wherein the third core is disposed
around the first tubing string.
5. The packer assembly of claim 1, wherein the proximal end of the
electrical wire is coupled to a power source at a surface above the
subterranean wellbore.
6. The packer assembly of claim 1, further comprising: at least one
cleat disposed on an outer surface of a body of the packer, wherein
the at least one cleat comprises electrically conductive material
and is configured to abut against a casing of the subterranean
wellbore, wherein the at least one cleat further has electrical
continuity with the second tubing string when the second tubing
string is coupled to the packer.
7. The packer assembly of claim 6, wherein the at least one cleat
is retractable relative to the body of the packer.
8. The packer assembly of claim 1, wherein the packer comprises a
body, wherein the body has disposed thereon at least one seal and
at least one slip section, wherein the at least one seal and the at
least one slip section are configured to abut against a casing of
the subterranean wellbore to provide a pressure separation within
the subterranean wellbore above the packer and the subterranean
wellbore below the packer.
9. The packer assembly of claim 1, wherein the first core comprises
magnetic properties.
10. A power transmission system for use within in a subterranean
wellbore having a casing disposed against a subterranean formation
and defining an outer perimeter of the subterranean wellbore and
forming a cavity, the system comprising: a power source disposed
proximate to a surface at an opening of the subterranean wellbore,
wherein the power source generates a first power; a first tubing
string segment disposed within the cavity; a first packer
mechanically coupled to a first distal end of the first tubing
string within the cavity of the subterranean wellbore, wherein the
first packer has a first feedthrough disposed therein along a first
height of the first packer; a second tubing string segment
mechanically coupled to a first bottom end of the first packer
within the cavity of the subterranean wellbore; a first core
disposed around the second tubing string segment adjacent to the
bottom end of the first packer and the first feedthrough; and a
first electrical wire disposed within the first feedthrough of the
first packer, wherein the first electrical wire has a first end
coupled to the power source and a second end wrapped around the
first core, wherein the first electrical wire receives the first
power from the power source, wherein the first power flowing
through the first electrical wire disposed around the first core
induces a second power in the first core, wherein the second power
in the first core generates a first current that flows on the
second tubing string away from the first core further into the
subterranean wellbore.
11. The system of claim 10, wherein the first packer comprises a
body, wherein the body has disposed thereon at least one seal and
at least one slip section, wherein the at least one seal and the at
least one slip section are configured to abut against the casing
within the cavity of the subterranean wellbore to provide a
pressure separation within the cavity of the subterranean wellbore
above the first packer and the subterranean wellbore below the
first packer.
12. The system of claim 10, further comprising: a second core
disposed around the second tubing string segment; and a second
electrical wire wrapped around the second core, wherein the first
current induces a third power in the second electrical wire.
13. The system of claim 12, further comprising: at least one first
electrical device coupled to the second electrical wire and
disposed adjacent to the second core, wherein the at least one
electrical device operates using the third power.
14. The system of claim 12, further comprising: a second packer
coupled to a second distal end of the second tubing string segment,
wherein the second core and the at least one electrical device are
disposed adjacent to the second packer, wherein the second packer
has a second feedthrough disposed therein along a second height of
the second packer, wherein the second electrical wire is disposed
within the second feedthrough; a third tubing string segment
mechanically coupled to a second bottom end of the second packer
within the cavity of the subterranean wellbore; and a third core
disposed around the second tubing string segment adjacent to the
bottom end of the second packer and the second feedthrough, wherein
the second electrical wire is further wrapped around the third
core, wherein the third power flowing through the second electrical
wire disposed around the third core induces a third power in the
third core, wherein the third power in the third core generates a
second current that flows on the third tubing string away from the
third core further into the subterranean wellbore.
15. The system of claim 14, further comprising: a fourth core
disposed around the third tubing string segment; a third electrical
wire wrapped around the fourth core, wherein the second current
induces a fourth power in the third electrical wire; and at least
one first electrical device coupled to the third electrical wire
and disposed adjacent to the fourth core, wherein the at least one
electrical device operates using the fourth power.
16. The system of claim 14, wherein the second packer comprises at
least one first cleat disposed on a first outer surface of the
second packer, wherein the at least one first cleat comprises
electrically conductive material and abuts against the casing.
17. The system of claim 16, wherein the casing, the second tubing
string segment, and the third tubing string segment are
electrically conductive, wherein the at least one first cleat forms
a first short that electrically isolates the second tubing string
segment from the third tubing string segment.
18. The system of claim 17, wherein the first packer comprises at
least one second cleat disposed on a second outer surface of the
first packer, wherein the at least one second cleat comprises the
electrically conductive material and abuts against the casing,
wherein the at least one second cleat forms a second short that
electrically isolates the second tubing string segment from the
first tubing string segment.
19. The system of claim 14, wherein the first current flows in a
loop down the second tubing string segment and up the casing
between the first core and the second core.
20. The system of claim 12, further comprising: a second packer
coupled to a second distal end of the second tubing string segment;
a third core disposed around the second tubing string segment
toward a second distal end of the second tubing string segment; a
second electrical wire wrapped around the second core, wherein the
first current induces a third power in the second electrical wire;
and at least one first electrical device coupled to the second
electrical wire and disposed adjacent to the second core, wherein
the at least one electrical device operates using the third power.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to U.S. Provisional Patent Application Ser. No. 62/349,769, titled
"Systems and Methods For Multi-Zone Power and Communications" and
filed on Jun. 14, 2016, the entire contents of which are hereby
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present application relates generally to power and data
transmission in a multi-zone completion environment using unique
magnetic coupling technology.
BACKGROUND
[0003] In resource recovery, it may be useful to supply electrical
power and monitor various conditions at locations in a wellbore
(also called herein a "borehole") remote from an observer. In
particular, it may be useful in completions and production
operations to provide power and monitor temperature, pressure,
fluid velocity or flowrate, and/or fluid characteristics within
isolated zones between packer elements in a wellbore. However, it
can be difficult or inconvenient to deliver power in such
environments. In some cases, electrical cables are installed in the
wellbore extending across each zone, but such cables sometimes are
difficult and expensive to install and maintain in an operationally
secure manner. In addition, it can be difficult to install a cable
in the confined space of an isolated zone. Additionally, such
cables may become eroded or damaged during installation or during
use. Such damage may require costly workovers and delays in oil and
gas production.
[0004] Wireless transmission of power and data has also not been an
option for transmitting into isolated zones between the packer
elements in a wellbore. Packer elements generally include sealing
glands and metallic slips to seal the packer element in position in
the annulus and to isolate zones within a wellbore. The metallic
components of the packer elements would short out any electrical or
signal path from the surface to the casing upon setting however,
and thus current and signal cannot flow wirelessly from the
surface, past the packer elements, and down the casing.
[0005] Because such boreholes may extend several miles, eliminating
some of the wires associated with power and sensor technology
becomes desirable since it is not always practical to replace power
sources or cables used in conventional boreholes.
SUMMARY
[0006] In general, in one aspect, the disclosure relates to a
packer assembly for disposal within a subterranean wellbore lined
by a casing. The packer assembly can include a packer having an
upper end, a lower end, and a feedthrough that traverses the packer
from the upper end to the lower end, where the upper end is
configured to couple to a first tubing string, where the lower end
is configured to couple to a second tubing string. The packer
assembly can also include a first core disposed around the second
tubing string adjacent to the lower end of the packer. The packer
assembly can further include an electrical wire disposed within the
feedthrough of the packer, where the electrical wire has a proximal
end and a distal end wrapped around the first core. The proximal
end of the electrical wire can be configured to receive a first
power from a power source disposed above the upper end of the
packer, where the distal end of the electrical wire is configured
to use the first power to induce a second power in the first core,
where the second power in the first core generates a first current
that flows on the second tubing string away from the first
core.
[0007] In another aspect, the disclosure can generally relate to a
power transmission system for use within in a subterranean wellbore
having a casing disposed against a subterranean formation and
defining an outer perimeter of the subterranean wellbore and
forming a cavity. The system can include a power source disposed
proximate to a surface at an opening of the subterranean wellbore,
where the power source generates a first power. The system can also
include a first tubing string segment disposed within the cavity.
The system can further include a first packer mechanically coupled
to a first distal end of the first tubing string within the cavity
of the subterranean wellbore, where the first packer has a first
feedthrough disposed therein along a first height of the first
packer. The system can also include a second tubing string segment
mechanically coupled to a first bottom end of the first packer
within the cavity of the subterranean wellbore. The system can
further include a first core disposed around the second tubing
string segment adjacent to the bottom end of the first packer and
the first feedthrough. The system can also include a first
electrical wire disposed within the first feedthrough of the first
packer, where the first electrical wire has a first end coupled to
the power source and a second end wrapped around the first core,
wherein the first electrical wire receives the first power from the
power source. The first power flowing through the first electrical
wire disposed around the first core can induce a second power in
the first core, where the second power in the first core generates
a first current that flows on the second tubing string away from
the first core further into the subterranean wellbore.
[0008] These and other aspects, objects, features, and embodiments
will be apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The drawings illustrate only example embodiments of systems
and devices for transmitting power and data to isolated zones in a
subterranean wellbore and are therefore not to be considered
limiting of its scope, as transmitting power and data to isolated
zones within a wellbore may admit to other equally effective
embodiments. The elements and features shown in the drawings are
not necessarily to scale, emphasis instead being placed upon
clearly illustrating the principles of the example embodiments.
Additionally, certain dimensions or positionings may be exaggerated
to help visually convey such principles. In the drawings, reference
numerals designate like or corresponding, but not necessarily
identical, elements.
[0010] FIG. 1 is a schematic diagram of a field system having
wireless power and data transmission capabilities within zones in a
subterranean wellbore, according to an example embodiment.
[0011] FIGS. 2A-2C show a circuit diagram and two schematic
diagrams, respectively, that includes a core according to an
example embodiment.
[0012] FIG. 3 is a current flow schematic at a downhole packer
assembly, according to an example embodiment.
[0013] FIG. 4 is an illustration showing how magnetic coupling
works in a cased well construct, according to an example
embodiment.
[0014] FIG. 5 is a cross-sectional schematic showing a magnetic
field generated by current sheets that surround a magnetic toroidal
core, according to an example embodiment.
[0015] FIG. 6 is a close-up schematic of a midstream portion of an
isolated zone, showing another case of current sheets on tubing and
inside of a casing wall, according to an example embodiment.
[0016] FIG. 7 is a close-up schematic of a midstream portion of an
isolated zone, having a sensor system placed along a cell or zone
region along tubing, according to an example embodiment.
[0017] FIG. 8 is a schematic diagram of a three-zone field system,
broken up to fit the page, according to an example embodiment.
[0018] FIG. 9A is a schematic of a packer assembly with embedded
inductive coupling and sensors, in an unset position, according to
an example embodiment.
[0019] FIG. 9B is a schematic of the packer assembly of FIG. 9A, in
set position, according to an example embodiment.
[0020] FIG. 10 is a schematic of a single zone simulator for
laboratory testing purposes, according to an example
embodiment.
[0021] FIG. 11 is a schematic of a dual-zone simulator for
laboratory testing purposes, according to an example
embodiment.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0022] Example embodiments directed to methods, systems, and
devices for inductively coupled power and data transmission to
isolated zones in a subterranean wellbore will now be described
with reference to the accompanying figures. Like, but not
necessarily the same or identical, elements in the various figures
are denoted by like reference numerals for consistency. In the
following description of the example embodiments, numerous specific
details are set forth in order to provide a more thorough
understanding of the disclosure herein. However, it will be
apparent to one of ordinary skill in the art that the example
embodiments herein may be practiced without these specific details.
In other instances, well-known features have not been described in
detail to avoid unnecessarily complicating the description.
[0023] A user as described herein may be any person that is
involved with a piping system in a subterranean wellbore and/or
transmitting power and data within the subterranean wellbore for a
field system. Examples of a user may include, but are not limited
to, a roughneck, a company representative, a drilling engineer, a
tool pusher, a service hand, a field engineer, an electrician, a
mechanic, an operator, a consultant, a contractor, and a
manufacturer's representative.
[0024] If a component of a figure is described but not expressly
shown or labeled in that figure, the label used for a corresponding
component in another figure can be inferred to that component.
Conversely, if a component in a figure is labeled but not
described, the description for such component can be substantially
the same as the description for the corresponding component in
another figure. The numbering scheme for the various components in
the figures herein is such that each component is a three or four
digit number and corresponding components in other figures have the
identical last two digits.
[0025] In the foregoing figures showing example embodiments of
wireless power and data transmission systems, one or more of the
components shown may be omitted, repeated, and/or substituted.
Accordingly, example embodiments of wireless power and data
transmission systems should not be considered limited to the
specific arrangements of components shown in any of the figures.
Further, any description of a figure or embodiment made herein
stating that one or more components are not included in the figure
or embodiment does not mean that such one or more components could
not be included in the figure or embodiment, and that for the
purposes of the claims set forth herein, such one or more
components can be included in one or more claims directed to such
figure or embodiment.
[0026] Terms such as "first", "second", "primary", "secondary",
"top", "bottom", "side", "width", "length", "upper", "lower",
"above", "below", "inner", and "outer" are used merely to
distinguish one component (or part of a component or state of a
component) from another. Such terms are not meant to denote a
preference or a particular orientation, and are not meant to limit
embodiments of wireless power and data transmission systems
described herein.
[0027] FIG. 1 shows a schematic diagram of a field system 100 that
can transmit power and data in a subterranean wellbore 102 during
completions and/or production operations in accordance with one or
more example embodiments. Referring now to FIG. 1, the field system
100 in this example includes a completed wellbore 102 within a
subterranean formation 104 below a ground surface 108. The point
where the wellbore 102 begins at the surface 108 can be called the
entry point. The subterranean formation 104 can include one or more
of a number of formation types, including but not limited to shale,
limestone, sandstone, clay, sand, and salt. In certain embodiments,
a subterranean formation 104 can also include one or more
reservoirs in which one or more resources (e.g., oil, gas, water,
steam) can be located. One or more of a number of field operations
(e.g., drilling, setting casing, extracting downhole resources) can
be performed to reach an objective of a user with respect to the
subterranean formation 104.
[0028] The wellbore 102 can have one or more of a number of
segments, where each segment can have one or more of a number of
dimensions. Examples of such dimensions can include, but are not
limited to, size (e.g., diameter) of the wellbore 102, a curvature
of the wellbore 102, a total vertical depth of the wellbore 102, a
measured depth of the wellbore 102, and a horizontal displacement
of the wellbore 102. Surface equipment 114 can be used to create
and/or develop (e.g., extract downhole materials) the wellbore 102.
The surface equipment 114 can be positioned and/or assembled at the
surface 108. The surface equipment 114 can include, but is not
limited to, a power source 195 and other equipment for multi-zone
completions, where the zones 120 are defined below.
[0029] Included in the field system 100 of FIG. 1 is an example
power delivery system 190. A completed wellbore 102 can include a
casing string 109 that defines the outer perimeter of the wellbore
102 and a production tubing 110 disposed within the cavity 188
(also called an annular volume herein) formed by the casing string
109. Extracted downhole materials can flow through the production
tubing 110 towards the surface equipment 114. The casing string 109
and the production tubing 110 are generally electrically
conductive. The wellbore 102 can include a number of perforated
zones 120 isolated from one another via isolation packer elements
124a, 124b, . . . 124n (referred to collectively herein as
isolation packer elements 124, where n refers to the packer closest
to the toe or distal end of the wellbore 102). Each packer element
124 is disposed within the cavity 188 between the tubing 110 and
the casing string 109. A zone 120 can be part of one or more
segments of the wellbore 102. In addition, or in the alternative, a
segment of the wellbore 102 can include one or more zones 120.
[0030] In this example, an electric line or cable 126 extends from
a system power source 195 above the surface 188 to a production
packer element 128. The packer element 128 is also disposed within
the cavity 188 between the tubing 110 and the casing string 109. In
certain example embodiments, the production packer element 128 and
the isolation packer elements 124 are feedthrough packers. In other
words, the production packer element 128 and the isolation packer
elements 124 can include feedthrough, channel, or other pathway to
allow a component (e.g., an electrical cable or electrical
conductors) of an example wireless power and data transmission
system to pass therethrough. In this case, the production packer
element 128 has feedthrough 125, and each of the isolation packer
elements 124 (with the exception of isolation packer element 124n)
has feedthrough 126.
[0031] Generally, in certain example embodiments, the production
packer element 128, by virtue of the cable 126 disposed in the
feedthrough 125, is in electrical communication with a first
magnetic toroidal core 130, and the first magnetic toroidal core
130 in turn transmits currents wirelessly via the
electrically-conductive production tubing 110 to an upper magnetic
toroidal core 132a that is electrically coupled to isolation packer
element 124a. Power can then be transmitted via wiring (hidden from
view) from the upper magnetic toroidal core 132a through the
feedthrough 126a of isolation packer element 124a to a lower
magnetic toroidal core 136a in an adjacent zone 120.
[0032] The lower magnetic toroidal core 136a in turn transmits
currents wirelessly via the electrically-conductive production
tubing 110 to an upper magnetic toroidal core 132b that is
electrically coupled to isolation packer element 124b. Power can
then be transmitted by wiring disposed within the feedthrough 126b
of the isolation packer element 124b to a lower magnetic toroidal
core 136b in the next zone. Generally, power can be transmitted
within a number of isolated zones 120 from a lower magnetic
toroidal core 136 to an upper magnetic toroidal core 132 in this
manner. Similarly power can be transmitted across adjacent zones
120 using wiring disposed within the feedthroughs 126 of the
corresponding isolation packer elements 124, where one end of the
wiring is coupled to an upper magnetic toroidal core 132 and the
other end of the wiring is coupled to a lower magnetic toroidal
core 136.
[0033] More specifically, by transformation of magnetic fields in
an upper magnetic toroidal core 132 to a "secondary winding" on the
core, the transformed current is manifested in the wire of the
winding and penetrated through isolation packer element 124 to the
lower side of the packer element 124 via an insulated and pressure
sealed feed-through. This wire carrying the secondary current is
then attached to a similar winding on lower magnetic toroidal core
136 on the lower side of the packer element 124 that will launch
current down the production tubing 110 within that zone 120 below
that packer element 124. By replication of this technique at each
isolation packer element 124, power may be translated through
several electrically isolated zones 120, without the use of
annulus-located cabling. In addition to power/current, data can
also be similarly transmitted across the zones 120 using this
transmission system. Absent the wiring in the feedthrough 126, the
tubing 110 in a zone 120 is electrically isolated from the tubing
110 in an adjacent zone 120 by the isolation packer element 124
that separates those two zones 120.
[0034] FIGS. 2A, 2B, and 2C show a wiring diagram, a schematic
diagram, and another schematic diagram, respectively, involving a
core 232 of an example power delivery system according to certain
example embodiments. Referring to FIGS. 1, 2A, 2B, and 2C, in
certain embodiments, the core 232 is toroidal and interacts with
two wires 257 (wire 257-1 and wire 257-2) of an electrical cable
256. Wire 257-1 carries inbound current and is wound around the
core 232 multiple times. The current flowing through wire 257-1
induces a current-generated magnetic field (H-field) vector within
the core, which in turn induces a current sheet that flows axially
through the center of the core 232. When a tubing pipe 210 is
disposed through the center of the core 232, this current sheet
flows along the tubing pipe 210. When there is an electrical short
(discussed below) between the tubing 210 and the adjacent casing
209, then the current that flows along the tubing 210 returns along
the casing 209. The distal end of wire 257-1 and wire 257-2 are
joined together, essentially creating a continuous wire 257. Wire
257-2 carries the return or outbound current back through the cable
256 to the source of the current.
[0035] In FIG. 2C, the schematic of FIG. 2B is expanded.
Specifically, the continuous wire 257 is shown partially disposed
within a feedthrough 226 of a packer 224. Wire 257-1 and wire 257-2
can be in the same feedthrough 226, or the packer can have multiple
feedthroughs 226, with wire 257-1 being disposed in one feedthrough
226 and wire 257-2 being disposed in the other feedthrough 226. The
wire 257 in this case is a single continuous wire that wraps around
core 232 at one end of the packer, and that also wraps around core
236 at the other end of the packer. The packer 226 electrically
isolates zone 220a from zone 220b. As a result, the current induced
through core 232 flows in a loop between tubing 210 and casing 209
within zone 220b, and the current flowing in a loop along tubing
210, through core 236, and returning along the casing 209 induces
current in the wire 257 wrapped around core 236 within zone
220a.
[0036] FIG. 3 illustrates a typical current flow scheme at a packer
assembly 370 according to certain example embodiments. Referring to
FIGS. 1-3, the packer assembly 370 includes a packer element 324
and at least one other component. In this case, the packer assembly
370 includes the packer element 324, toroid 332, toroid 336, and a
number of electrically-conductive cleats 371 disposed along the
outer perimeter of the packer element 324. When the tubing 310 is
coupled to the packer assembly 370, the cleats 371 make an ohmic
(resistive) connection to the tubing string 310. In other words,
there is electrical continuity between the cleats 371 and the
tubing 310 when the tubing 310 is coupled to the packer assembly
370. The cleats 371 can be protracted when the packer assembly 370
is disposed at a desired location within the wellbore. When this
occurs, the cleats 371 make contact with the casing 309 and create
the short 375, which provides a return path for the current that
originates from the power source (e.g., power source 195) and flows
through the tubing 310. The cleats 371 also mechanically anchor the
packer assembly 370 to the casing 309.
[0037] Current in zone 320-1 on production tubing 310 above packer
assembly 370 induces an attendant magnetic field in an upper
magnetic toroidal core 332 (enhanced by the special core material).
In certain example embodiments, the current path 385 in the
tubing-casing skins constitutes one full turn of a distributed
winding (on the associated toroidal core), a winding we will here
dub, `primary` winding, as current in the production tubing 310
returns back in the casing 309 inner diameter (ID) skin and passes
the upper magnetic toroidal core 332 inside and outside that core
332. There is a wire winding of several turns on the upper magnetic
toroidal core 332 that is considered a `secondary` winding.
[0038] One or more leads (also called wires herein) from this
secondary winding are fed through the packer assembly 370 housing
in a sealed feedthrough 326 to the other (lower) side of the packer
assembly 370. The one or more wires are hidden from view in this
example. If shown, there can be a single continuous wire that wraps
around core 332 and core 336, while a remainder of the wire is
disposed within the feedthrough 326. This winding in the upper
magnetic toroidal core 332 then drives a similar winding on a lower
magnetic toroidal core 336, inducing a current in a current path
385-2 on the production tubing 310 in the string section (zone
302-2) below this packer assembly 370. In certain example
embodiments, the packer assembly 370 is manufactured with the upper
toroidal core 332 and the lower magnetic toroidal core 336
integrated and wired in, and can be assembled on site by the
completion crew in a conventional manner with no special techniques
required.
[0039] In certain applications, the winding turn ratios of each
magnetic toroidal core (e.g., core 332, core 336) allow the
advantage of relatively high current in the production tubing 310,
and thus low voltage between the production tubing 310 and casing
309 so that the insulation requirements of the wellbore annulus
(cavity 388) are reduced. Some salt-based packer fluids may have
adequately high resistive nature for manageable system power loss,
reducing some of the "insulative" character of a possible needed
packer fluid. Some high density packer fluids may become more
`conductive` as an electrical conductor as the density and salt
character increases. This may or may not pose a challenge for the
power and communications ability of a particular zone 320, but
should be considered in the early design phase for the
completion.
[0040] FIG. 4 illustrates how magnetic coupling works in a cased
well construct. Referring to FIGS. 1-4, magnetic coupling occurs
where the H-field is `collected` by the internal toroidal core
magnetic material, intersected by the current-generated magnetic
field (H-field) vector 451 shown in FIG. 4. Electrical current
always generates an attendant magnetic field, as explained by
Faraday's Law of Induction. These cores (e.g., core 332) use
materials in their bulk that have a high susceptance' to magnetic
fields that, in a way, concentrate available field density. The
toroidal shape of the core can be used to act as a magnetic antenna
in this application, where the system current 486 follows the
current path 485 defined as being on the tubing surface 410 and
returning on the inside of the casing 409, effectively fully
wrapped around the toroidal core.
[0041] In certain example embodiments, an effective magnetic
`antenna` in the present application may be a toroidal, magnetic
core with the largest outer diameter (OD) possible (as large as the
`drift` diameter) and the tightest possible fit around the outer
surface of the tubing 410. The closer the "skin" current flow is to
the core magnetic material, the better the coupling to the magnetic
fields is, and the effective power-loss per coupling is reduced.
Limitations on these mechanical dimensions are understood by one
having ordinary skill in the art for applicable and safe, useable
packer designs. It should be noted that this is specifically an
alternating current (AC) current application; direct current (DC)
current will not transfer power continuously in these example power
transmission systems using magnetically coupled applications.
[0042] The current (I) 486 runs along the surface of the tubing 410
and on the inside surface of the casing 409 to form the current
path 485 in a complete loop. The bulk of the current flows in a
thin outer layer of the conductive metals, generally referred to as
the current "skin-depth". The depth or cross-section of the metal
conductor where conduction is present improves as the
skin-thickness increases (lower Z-axis resistance per unit length)
deeper into the wall of the conductor 410. The effective thickness
gets thinner as the operating frequency of the current 486
increases. In certain example embodiments, communications may be
operated at lower frequencies as these losses are reduced as that
"skin" gets thicker. In certain embodiments, where power
requirements increase, power is transmitted at frequencies of
400-2000 Hz and lower.
[0043] As shown in FIG. 4, the dashed line portion of the current
path 485 implies circuit completion at a hanger or packer to the
right of the drawing, where the tubing 410 and casing 409 become
electrically connected or terminated by another packer or device
that brings the tubing 410 and casing 409 in electrical connection.
There are a number of options available for initial power and
communications feed at the ground level including "hot-string"
techniques described, for example, in U.S. Pat. No. 9,316,063, to
the customary cabled drop from hanger to top packer.
[0044] FIG. 5 illustrates additional details of the magnetic field
generated by the current sheets that surround a magnetic toroidal
core cross-section. Referring to FIGS. 1-5, the current 586 in the
production tubing 510 and the inside wall of the casing 509 are
wave-generated and "coherent", which means that, at any point in
time, they are opposite in direction, the same in signal timing,
and essentially wrap around the magnetic material of the core 532.
The coaxial construct of a classic well produces a wave guide, thus
the currents (both power and communications) are the result of a
"traveling wave". This forces the E-field and magnetic field (shown
by magnetic field vector 551 in FIG. 5) into the annular volume 588
of the guide away from the two conductors (in this case, the tubing
510 and the casing 509). Current remains in the `skin` of these
conductors. This simplifies the skin-depth calculation as there is
no magnetic term in that skin-depth calculation. In other words,
there is no further loss due to magnetic materials (steel, etc.) in
the tubing 510 and the casing 509.
[0045] In addition, the `sheet-current` (represented by the current
586 in the tubing 510 in FIG. 5 and normally called `J`), is the
current density where current 586 is the integral of J over the
conductive area involved. The core material in the cores 532 (or
other cores, such as core 336) described herein may be made of
various alloys of ferrite or a special metal tape, such as layers
of magnetic grade iron alloy that capture and concentrate the field
inside the effective current loop. In certain example embodiments,
a copper winding 557 for the `secondaries` may be employed around
the core 532 to improve efficiency. The type of material of the
core 532 can depend on one or more of a number of factors. For
example, the type of material of the core 532 can depend on the
frequencies expected for both power and communications.
[0046] The induced voltage in the attached, multi-turn winding 557
(core "secondary") is transformed from the voltage between the
tubing 510 and the casing 509 (effectively one turn) to a voltage
that is multiplied by the number of secondary turns (e.g. five
turns) that are wound around the cross-section of the core 532. At
the same time the current in that multi-turn winding 557 is
one-fifth (for five secondary turns) the current 586 in the current
sheet of the tubing 510. The power equation remains the same in
that what was reduced in current is balanced by the five-times (for
five secondary turns) increase in voltage. In certain embodiments,
the "traveling wave" idea also supports the possibility of having a
core 532 placed anywhere along the tubing 510 between packers used
as a coupler to the system power/communication stream. The wave
exists all along the zone or cell structure and makes the
connection to power and signals in that wave easily accessible.
[0047] Liquids and solids can present a resistive path across the
annular volume 588 between the tubing 510 and casing 509 (a
`shunt-current` path) that will spill off power to heating material
(e.g., brine, salt included fluids) in the annular volume 588. A
packer fluid that has a bulk electrical resistive character would
shift the equation. System designers would favor high current 586
on the tubing 510, less voltage across the annulus 588. That
annular power loss is quantified by the equation P.sub.1=E.sup.2/R
where the R is the effective resistance, tubing 510 to casing 509,
of the annulus volume 588. If the R is very large (toward an open
circuit), the losses to the annular volume 588 are very low. The
advantage of the above magnetically coupled zone transformation
resulting from the cores (e.g., core 532) having a large
turns-ratio puts high current 586 on the tubing 510 and very low
voltage in the annular volume 588 where resistive (semi-conductive)
packer fluids may be needed and are tolerable. These relatively
small magnetic cores 532 capture the magnetic field 551 from the
current passing through and around the core 532. Not all of the
magnetic field 551 can be effectively captured in most cases due to
mechanical dimensions and product availability or custom sizes.
However most applications presented by the design of a conventional
well construct will allow a practical solution for systems (e.g.,
electrical devices 750, described below) that require approximately
1/2 kW or less of continuous power.
[0048] FIG. 6 illustrates a close-up of a midstream portion of an
isolated zone 620, and is intended to show another case of the
current 686 on tubing 610 and inside the casing wall 609. The
current sheets (sharing the direction with the current 686 in the
tubing 610) link magnetic couplers (toroidal cores 636 and 632) to
that flow of current 686 such that anywhere along the tubing 610
between core 636 and core 632, power and/or communications access
can be harvested for use by one or more electrical devices. The
packer shorts 675 (in this case, short 675a and 675b), which are
each a short between the tubing 610 and the casing 609, are shown
in FIG. 6. These shorts 675 represent the boundaries of this
completion cell 620 (zone 620), which creates a circuit closed loop
where those currents 686 and corresponding current sheets are
created by the induced current from one magnetic core 636 and/or
the other magnetic core 632.
[0049] The winding wires 657 of the core secondaries exit the zone
620 through the feedthrough 626 of the packer 624 to link to the
next adjacent zone 620 or cell 620. For example, winding wire 657a
acts as the secondary wrapped around core 636 and are disposed
within the feedthrough 626a of the packer 624a to act as the
secondary wrapped another core (e.g., core 632b) in an adjacent
zone 620. As another example, winding wire 657b acts as the
secondary wrapped around core 632 and are disposed within the
feedthrough 626b of the packer 624b to act as the secondary wrapped
another core (e.g., core 636c) in an adjacent zone 620. This system
and process is replicated at each cell 620 or zone 620. It should
be noted that each winding wire 657 (e.g., winding wire 657a) can
be a single continuous wire. Alternatively, a winding wire 657 can
be two wires whose distal ends are joined together proximate to the
core that they are wrapped around.
[0050] A completion system may have cable feed to a penetrated, top
packer (e.g., packer 128) from the hanger. In cases where the top
packer is a considerable distance down, this would eliminate the
need for centralizers and high resistance (insulating) packer
fluids. The following (further downhole) production zones would
then use the example magnetically coupled packer approach, such as
shown and described herein, for power and communication feed
through the producing cells 620 below (further downhole). Each zone
620 or electric cell 620 is treated as autonomous from all
neighboring cells 620 due to the packer/casing shorts 675
therebetween, where the only link or supply line is the winding
wires 657 disposed in the feedthrough 626 of each packer 624 to the
next cell 620.
[0051] FIG. 7 illustrates a close-up of a midstream portion of an
isolated zone 720, having an electrical device 750 (in this case, a
sensor system) placed within the cell 720 or zone 720 along the
tubing 710. An electrical device 750 can be any device that uses
power to operate and/or communicate. Examples of an electrical
device 750 can include, but are not limited to, a sensor (e.g.,
pressure, temperature, flow), a solenoid (e.g., for a valve), a
switch, a battery, a capacitor, and a relay. The example system can
be designed to transmit both operational power for active circuits
and small motorized devices. Also, using power-conditioning,
energy-storage techniques could invoke valve and other mechanical
functions in each zone (e.g., zone 720) requiring significant,
short-lived mechanical force.
[0052] In example embodiments, in addition to or in the alternative
of a sensor system, the electrical device 750 can include a
solenoid (for a valve), fluid identifying sensors, flow measuring
devices, pressure sensors, and temperature sensors. The electrical
devices 750 can be placed at any location along the cell 720 or
zone 720 along the tubing 710. In certain embodiments, the
electrical device 750 can be a multitude of remote sensing and
control devices located throughout the zone 720.
[0053] In some cases, as shown below with respect to FIG. 8, a zone
720 can be very long and/or there are multiple electrical devices
750 spread out within the zone 720. In such a case, one or more of
these electrical devices 750 can be linked to the example power
delivery system within the zone 720 via an additional core (e.g.,
core 736b) and/or another winding (e.g., winding 757c) around a
cell-terminating core (core 732) at a packer 724 or packer
assembly, as applicable. An additional winding (e.g., winding 757c)
can be included on any of the cores (e.g., core 736) in the zone
720, regardless of location (in the middle of the tubing 710, at a
packer 724) of the core within the zone 720. Each winding (e.g.,
winding 757a) can be of any number of turns to accommodate the
operation and voltage needs of electrical device 750 coupled to and
receiving power from the winding. Higher turns ratio could be
advantageous for a power conditioning unit where a relatively high
voltage will be capacitor-stored, for a necessary high-action
mechanical function.
[0054] The electrical devices 750 (e.g., sensors) may be placed
anywhere in the zone 720 proximate to the tubing 710 and can be
co-located with any desired function. One or more of the electrical
devices 750 can be part of a packer assembly, included at a packer
core with an extra winding on the packer core. The complexity of
the electronics in a number of sensor packages is only governed by
the expected temperature range those electronic devices will be
exposed to. In short, if the environmental thermal character of the
zone is not extreme, highly complex, processor-based electronics
could be an option as an electrical device 750 for the string
design. This would lend itself to individually addressed
sensor/valve stations along any zone section where those favorable
thermal conditions exist.
[0055] In certain example embodiments, there can be multiple
electrical devices 750 in a zone (e.g., zone 720). In addition, or
in the alternative, there can be multiple zones with one or more
electrical devices 750. In such cases, each electrical device 750
can have an assigned serial communications address so that
functions within a particular zone 720 and/or between zones can be
treated and/or interrogated individually or totally. In certain
applications, there may be a need to control contact or direct
electrical conduction of tubing 710 to casing 709 in the inter-zone
areas of tubing/casing discipline (tubing 710 centralization in the
wellbore). Mid-zone "shorts" 775 (between each of the packers 726)
between tubing 710 and casing 709 in a zone 720 can significantly
affect the passage of power and signals to any following (downhole)
core transformers. Coatings and insulated centralizer techniques
can be used as part of the completions design plan to help improve
the transmission of power and signals using example
embodiments.
[0056] FIG. 8 shows a schematic of a power delivery system 890 with
three zones 820, broken up to fit the page, according to an example
embodiment. Referring to FIGS. 1-8, not shown in FIG. 8 are the
usual insulated centralizers or indication of packer fluids. The
system 890 of FIG. 8 can transmit power and data in a subterranean
wellbore during completions and/or production operations in
accordance with one or more example embodiments. The system 890 of
FIG. 8 is substantially the same as what is described above with
respect to FIGS. 1-7, except as specifically stated below. For the
sake of brevity, the similarities will not be repeated herein
below.
[0057] The example system 890 includes electrical equipment 850
located within three of the zones 820. In this case, zone 820a is
adjacent to zone 820b, which is adjacent to zone 820c, which is
adjacent to zone 820d. Zone 820a and zone 820b are separated by a
short 875a through packer 824a. Zone 820b and zone 820c are
separated by a short 875b through packer 824b. Zone 820c and zone
820d are separated by a short 875c through packer 824c. There is no
electrical equipment within zone 820a. Electrical equipment 850a is
located in zone 820b, electrical equipment 850b is located in zone
820c, and electrical equipment 850c is located in zone 820d.
[0058] Zone 820b, zone 820c, and zone 820d each have three cores,
meaning that an extra core has been added to each of those zones,
as described with respect to FIG. 7 could be a configuration of the
system 890. Specifically, in zone 820b, core 836a is coupled to
packer 824a, core 832b is coupled to packer 824b, and core 836b is
disposed therebetween, adjacent to electrical device 850a. In this
way, core 836b can be used to provide power directly to electrical
device 850a based on the current flowing through tubing 810 induced
by and between core 836a and core 832b.
[0059] In addition, in zone 820c, core 836c is coupled to packer
824b, core 832c is coupled to packer 824c, and core 836d is
disposed therebetween, adjacent to electrical device 850b. In this
way, core 836d can be used to provide power directly to electrical
device 850b based on the current flowing through tubing 810 induced
by and between core 836c and core 832c. Further, in zone 820d, core
836e is coupled to packer 824c, another core (not shown) is coupled
to another packer (not shown), and core 836f is disposed
therebetween, adjacent to electrical device 850c. In this way, core
836f can be used to provide power directly to electrical device
850c based on the current flowing through tubing 810 induced by and
between core 836e and the additional downstream core. As an
alternative to having a third core, as discussed above with respect
to FIG. 7, one of the cores (e.g., core 832b) coupled to a packer
(e.g., packer 824b) can use an additional winding on the core above
or below the electrical device (e.g., electrical device 850a).
[0060] FIG. 9A shows a schematic of a packer assembly 970 an unset
condition and with embedded inductive coupling and electrical
devices 950, according to an example embodiment. FIG. 9B shows a
schematic of the packer assembly 970 of FIG. 9A in a set condition
according to an example embodiment. Referring to FIGS. 1-9B, the
components of the packer assembly 970 are substantially the same as
those described above, and for the sake of brevity, the
similarities may not be repeated herein. The packer assembly 970 is
in an unset position because the packer seals 967 are deflated, and
the upper slip section 966 and the lower slip section 964 are
retracted (not protracted). As a result, there is no pressure
separation above and below the packer 924. In other words, the
packer seals 967, the upper slip section 966, and the lower slip
section 964 of the packer 924 fail to contact the casing 909,
allowing the cavity 988 to be substantially continuous (from a
pressure standpoint) along the length of the packer assembly 970,
forming a single zone 920.
[0061] Since the packer assembly 970 in this case has embedded
inductive coupling, core 932 is embedded into the top of the packer
assembly 970, and core 936 is embedded into the bottom of the
packer assembly 970. Core 932 and core 936 are coupled to each
other by winding wires 957, which are disposed in the feedthrough
926 in the packer assembly 970 and are wound around core 932 and
core 936. Electrical device 950 is also embedded into the bottom of
the packer assembly 970 and is provided power from winding wire 957
or a different winding wire wrapped around core 936.
[0062] In FIG. 9B, the packer seals 967, the upper slip section
966, and the lower slip section 964 of the packer 924 are all
expanded/protracted so that they abut against the inner wall of the
casing 909. As a result, zone 920a is physically separated from
zone 920b, and a pressure separation is created between the two
zones 920. The upper slip section 966 and the lower slip section
964 can be electrically-conductive and act as the cleats (not shown
in FIGS. 9A and 9B) described above in that the slip sections can
create a short with the casing 909. Alternatively, the packer
assembly 970 can include a number of cleats to create the shorts
that allow current flowing along the tubing 910 to return along the
casing 909 within a zone 920 (e.g., zone 920a, zone 920b). The
electrical device 950 can thus be used to measure temperature,
pressure, flow, and/or other parameters in zone 920b below the
packer 924.
[0063] FIG. 10 shows a schematic of a single zone 1020 simulator
that was tested in a laboratory to verify the practical use of the
example system of power and data transmission. A magnetic toroidal
core 1032 and core 1036 were placed at either end of the zone 1020,
and coupled to the current sheet in the tubing 1010-casing 1009
loop-current along the path shown for current 1086. The electrical
device 1050 receives power induced from core 1036 using winding
wires 1057.
[0064] FIG. 11 shows a schematic of a dual-zone 1120 simulator that
was tested in a non-idealized laboratory arrangement to measure
power loss across a zone 1120b. A magnetic toroidal core 1132a and
core 1136a were placed at either end of zone 1120a, and coupled to
the current sheet in the tubing 1110-casing 1109 loop-current along
path shown for current 1186a. Similarly, a magnetic toroidal core
1132b and core 1136b were placed at either end of zone 1120b, and
coupled to the current sheet in the tubing 1110-casing 1109
loop-current along the path shown for current 1186b.
[0065] Initial lab results indicate that a five-zone completion
could provide 10-15 watts at zone 1120b with about 80 watts applied
by the power source 1195 (e.g., at the surface level). Specified
custom made cores for intended power and communication frequencies
of a maximum OD, minimum ID design (as mechanically practicable),
could increase the efficiency of the multi-zone system
significantly (which was not done for the laboratory tests).
However, an optimized system could be employed to supply power of
about 0.5 KVA and below to an electrical device or devices using
this example system and technique.
[0066] The systems, methods, and apparatuses described herein allow
for transmitting power and data within a wellbore. Supply of power
using magnetic toroidal cores and existing wellbore hardware, such
as a tubing string and casing, reduces the need for conventional
power cabling completion insertions within each zone of a wellbore.
The application of example embodiments may employ relatively high
current and moderately high voltage use of the well structure.
[0067] Although embodiments described herein are made with
reference to example embodiments, it should be appreciated by those
skilled in the art that various modifications are well within the
scope and spirit of this disclosure. Those skilled in the art will
appreciate that the example embodiments described herein are not
limited to any specifically discussed application and that the
embodiments described herein are illustrative and not restrictive.
From the description of the example embodiments, equivalents of the
elements shown therein will suggest themselves to those skilled in
the art, and ways of constructing other embodiments using the
present disclosure will suggest themselves to practitioners of the
art. Therefore, the scope of the example embodiments is not limited
herein.
* * * * *