Note: Descriptions are shown in the official language in which they were submitted.
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MANAGING STRAIN ON A DOWNHOLE CABLE
TECHNICAL BACKGROUND
[0001] This disclosure relates to managing strain on a downhole cable,
BACKGROUND
[0002] A downhole cable is often used to convey a downhole tool into a
wellbore. For example, a downhole cable can be a strong wire (e.g., wireline,
slickline, and/or other downhole cable) for withstanding the dynamic and
static
weight of the downhole tool. The weight includes the dynamic and static
tension
forces in the downhole cable when the downhole tool accelerates or
decelerates. The
wire can also communicate telemetric signals with the downhole tool. The
dynamic
weight of the downhole tool can slightly stretch the downhole cable. Other
factors
can also change the strain in the downhole cable.
DESCRIPTION OF DRAWINGS
[0003] FIG. 1 is a schematic cross-sectional side view of a well system
with
an example downhole cable;
[0004] FIGS. 2A-2B illustrate cross-sectional views of example
embodiments
of a downhole cable that manages strain on components of the cable;
[0004] FIGS. 3A-3B illustrate cross-sectional views of example
embodiments
of a downhole cable that manages strain on components of the cable; and
[0005] FIG. 4 illustrates an example method performed with a downhole
cable.
DETAILED DESCRIPTION
[0006] The present disclosure relates to managing strain on a downhole
cable,
such as a slickline or wireline, that includes a wire coupled with a
communication
line, such as a fiber optic cable or metallic (or non-metallic) conductor. In
a general
implementation, a downhole cable includes a wire to support a downhole tool
string;
and a communication line non-linearly coupled with the wire, the communication
line
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sized to communicate instructions, that include at least one of logic or data
to the
downhole tool, and to elongate based on an axial force that acts on the
downhole
cable.
[0007] In a first aspect combinable with the general implementation, the
communication line includes at least one of a fiber optic line or a metallic
conductor.
[0008] In a second aspect combinable with any of the previous aspects,
the
wire includes a composite material.
[0009] In a third aspect combinable with any of the previous aspects,
the
communication line is non-linearly embedded in a matrix of the composite
material.
[0010] In a fburth aspect combinable with any of the previous aspects,
the
communication line is non-linearly embedded in the matrix of the composite
material
in a helical or zig-zag path.
[0011] In a fifth aspect combinable with any of the previous aspects,
the wire
includes a flexible rod, and the communication line is non-linearly wrapped
around
the flexible rod.
[0012] A sixth aspect combinable with any of the previous aspects
further
includes a coating that at least partially covers the communication line and
the
flexible rod.
[0013] in a seventh aspect combinable with any of the previous aspects,
the
coating includes polyether ether ketone.
[0014] In an eighth aspect combinable with any of the previous aspects,
for a
particular portion of the downhole cable, a length of the communication line
that
extends between ends of the particular portion is greater than a length of the
wire that
extends between the ends of the particular portion.
[0015] In a ninth aspect combinable with any of the previous aspects, a
value
that defines an allowable strain of the wire is greater than a value that
defines an
allowable strain of the communication line.
[0016] In a tenth aspect combinable with any of the previous aspects, a
diameter of the d.ownhole cable is about 0.138 inches.
[0017] In an eleventh aspect combinable with any of the previous
aspects, the
composite material includes polyphenylerie sulfide.
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[0018] In a twelfth aspect combinable with any of the previous aspects,
the
downhole cable includes a slickline, and the wire includes a single solid
wire.
[0019] In a thirteenth aspect combinable with any of the previous
aspects, the
downhole cable includes a wireline, and the wire includes a braided wire.
[0020] Another general implementation includes a method of managing
strain
on a downhole cable that includes running a downhole tool coupled to a
downhole
cable into a wellbore, the downhole cable including a wire and a communication
line
non-linearly coupled with the wire; operating the dowrihole tool in the
wellbore by
transmitting, on the communication line, instructions that include at least
one of logic
or data between the downhole tool and a terranean surface; receiving a force
in an
axial direction on the downhole cable; and in response to the received force,
elongating the communication line from a substantially non-linear position
toward a
substantially linear position.
[0021] In a first aspect combinable with the general im.plementation,
the
communication line includes at least one of a fiber optic line or a metallic
conductor.
[0022] In a second aspect combinable with any of the previous aspects,
the
communication line is non-linearly embedded in a matrix of a composite
material.
[0023] in a third. aspect combinable with any of the previous aspects,
elongating the communication line from a non-linear position toward a linear
position
includes elongating the communication line from a helical or zig-zag position
toward
the substantially linear position.
[0024] A fourth aspect combinable with any of the previous aspects
further
includes receiving a second force in the axial direction on the downhole cable
that is
less than the received force; and in response to the second force, shortening
the
communication line toward the substantially non-linear position.
[0025] In a fifth aspect combinable with any of the previous aspects,
the wire
includes a flexible rod, and the communication line is non-linearly wrapped
around
the flexible rod.
[0026] In a sixth aspect combinable with any of the previous aspects,
the
downhole cable further includes a coating that at least partially covers the
communication line and the flexible rod.
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[0027] In a seventh aspect combinable with any of the previous aspects,
for a
particular portion of the downhole cable, a length of the communication line
that
extends between ends of the particular portion is greater than a length of the
wire that
extends between the ends of the particular portion.
[0028] In an eighth aspect combinable with any of the previous aspects,
the
logic or data includes values associated with telemetry data.
[0029] Another general implementation includes a downhole conductor that
includes a wire that extends a first length between a first end of the
downhole
conductor and a second end of the downhole conductor, the wire sized to
support a
downhole tool string in a wellbore; and a data conductor to transmit at least
one of
logic or data with the downhole tool string and coupled with the wire, the
data
conductor extending a second length between the first end of the downhole
conductor
and the second end of the downhole conductor, the second length greater than
the first
length.
[0030] In a first aspect combinable with the general implementation, the
data
conductor is embedded in a helical path through a composite material of the
wire.
[0031] In a second aspect combinable with any of the previous aspects,
the
composite material includes a single homogenous tension member, and the data.
conductor is wound in a helical path around the member.
[0032] A third aspect combinable with any of the previous aspects
further
includes a protective coating wrapped around the data conductor and th.e
tension
member.
[0033] In a fourth aspect combinable with any of the previous aspects,
the
data conductor includes an optical fiber.
[0034] In a fifth aspect combinable with any of the previous aspects,
each of
the wire and the data conductor include respective distal ends that are
coterminous
with the first end of the downhole conductor and respective proximal ends that
are
coterminous with the second end of the downhole conductor.
[0035] In a sixth aspect combinable with any of the previous aspects,
the
downhole conductor includes a slickline, and the wire includes a single
homogeneous
wire, and the data conductor includes a fiber optic conductor.
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[0036] Various implementations of a downhole cable (e.g., downhole
carrier,
downhole conveyance, or downhole cable) in accordance with the present
disclosure
may include one, some, or all of the following features. For example, the
communication line may be non-linearly embedded in a downhole cable in a
spiral,
helical, zig-zag, or sinusoidal path. The communication line can include a
fiber optic
line and conductor lines, and the communication line can be enclosed in a
single line
or be twisted using multiple lines. In some implementations, the communication
line
may be non-linearly wrapped around the composite material including a flexible
rod.
The non-linear integration of the communication line, either embedded
internally or
wrapped externally, can relieve excessive strain from the communication line
when
the composite material extends due to static and dynamic tensile loads, as
well as
torsional loads and/or temperature variations. Further, in some
implementations, a
downhole cable according to the present disclosure may decrease linear and
torsional
strain in the static and dynamic loading of the cable.
[0037] FIG. 1 is a schematic cross-sectional side view of a well system
100
with an example downhole cable 110. The well system 100 is provided for
convenience of reference only, and it should be appreciated that the concepts
herein
are applicable to a number of different configurations of well systems. The
well
system 100 includes a wellbore 108 that extends from a terranean surface 105
through
one or more subterranean zones of interest 101. In FIG. 1, the wellbore 108
initially
extends vertically and transitions horizontally. in other instances, the
wellbore 108
can be of another position, for example, deviates to horizontal in the
subterranean
zone 101, entirely substantially vertical or slanted, it can deviate in
another manner
than horizontal, it can be a multi-lateral, and/or it can be of another
position.
[0038] At least a portion of the illustrated wellbore 108 may be lined
with a.
casing 106, constructed of one or more lengths of tubing, that extends from
the
terranean surface 105, downhole, toward the bottom of the wellbore 108. The
casing
106 provides radial support to the wellbore 108 and seals against unwanted
communication of fluids between the wellbore 108 and surrounding formations.
Here, the casing 106 ceases at or near the subterranean zone 101 and the
remainder of
the wellbore 108 is an open hole, e.g., uricased. In other instances, the
casing 106 can
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extend to the bottom of the wellbore 108 or can be provided in another
position and in
multiple circumferences or thicknesses (e.g., conductor casing or otherwise).
[0039] As illustrated, a downhole tool string 120 is coupled to (e.g.,
supported
by) the downhole cable 110, which can be, for example, a wireline, a
slickline, an
electric line. In the illustrated embodiment, the downhole cable 110 can
support a
downhole tool string (e.g., one or more downhole tools). In this example, the
downhole cable 110 includes a braided (e.g., multiple bound, or intertwined,
wires
such as wireline or electric line) or solid wire (e.g., a single wire such as
slickline) and
a communication line. The communication line is coupled with the braided or
solid
wire such as, for example, embedded in, intertwined with one or more wires, or
wrapped around or within one or more wires, in a non-linear (e.g., undulating,
helical,
zig-zag, or otherwise) configuration.
[0040] In the illustrated example, the communication line may have a
different
Young's modulus than a Young's modulus of the braided or solid wire. In such
cases,
a maximum strain that the communication line may tolerate (e.g., before
failure) may
be different than a maximum strain that the braided or solid wire can tolerate
(e.g.,
before failure). In some aspects, for instance, the braided or solid wire may
tolerate a
higher (e.g., substantially) maximum strain before failure as compared to the
communication line.
[0041] In some aspects, a particular length (e.g., between two
terminating
ends) of the downhole cable 110 includes a length of the braided or solid wire
and a
length of the communication line. In the particular length of the downhole
cable 110,
the respective lengths of the braided or solid wire and the communication line
may
also terminate at or close to the terminating ends of the downhole cable 110.
In some
aspects, the length of the communication line may be greater than (e.g.,
slightly or
substantially) the length of the braided or solid wire because of, for
example, the non-
linear configuration in which the communication line is coupled with the
braided or
solid wire.
[0042] In one example embodiment (as described more fully with respect
to
FIGS. 2A-2B and 3A-3B), the downhole cable 110 is a slickline that includes a
solid
wire and a communication line. The slickline supports tool string 1.20 and can
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communicate instructions, data, and/or logic between the tool string 120 and
the
terranean surface 105 though the communication line (e.g., optical fiber,
metallic
conductor, or non-metallic conductor). The communication. line of the
slickline is
non-linearly coupled with the solid wire such that strain that exceeds a
maximum
allowable strain of the communication line, but not a maximum allowable strain
of the
solid wire, does not cause failure of the communication line or the slickline.
[0043] In some implementations, the downhole tool string 120 may
communicate with computing systems or other equipment at the surface 105 using
the
communication capabilities of the downhole cable 110. For example, the
downhole
tool string 120 may send and receive electrical signals andlor optical signals
(e.g.,
data and/or logic) through respective conductor wire andlor fiber optics of
the
communication line within the downhole cable 110. In addition, the downhole
tool
string 120 may be lowered or raised relative to the wellbore 108 by
respectively.
extending or retrieving the downhole cable 110.
[0044] During operation, variable tension loading is applied to the
downhole
cable 110 when the downhole cable 110 lowers or raises the downhole tool
string 120.
The tension loading is related to the mass, acceleration, and deceleration of
the
downhole tool string 120. The tension loading can extend the downhole cable
110
axially. The amount of extension is related to the magnitude of the tension
loading,
the stiffness (e.g., Young's modulus) of the downhole cable 110, and
parameters (e.g.,
diameter) of the downhole cable 110. Because the downhole cable 110 is placed
downhole where temperature varies, the downhole cable 110 may also experience
thermal expansion or contraction. The thermal expansion or contraction can
also
contribute to the amount of extension of the downhole cable 110,
[0045] When the downhole cable 110 includes two or more different
materials, the extension due to tensile loading and thermal effect can be
different in
the two or more materials. For example, the braided or solid wire of the
downhole
cable 110 can comprise a composite material, while the communication line can
comprise a conductive or fiber optic material (or other data conductor). The
braided
or solid wire of the cable 110 and the communication line may have different
extension limits (e.g., maximum allowable strains without structural damage)
and
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different changes in length when experiencing the same temperature changes
(e.g.,
different coefficient of thermal expansion). Strain values can employ
different
definitions, for example, engineering strain is the ratio between the total
deformation
to the original length, e.g., the amount of deformation of unit length.
[0046] The different extension limits can impose limitations to the
downhole
cable 110 if the braided or solid wire and the communication line were
integrated
linearly (e.g., combined in a one-to-one length ratio). For example, as
described, the
braided or solid wire can have a higher allowable strain level than the
communication
line (e.g., made of optical fibers). This can result in a lower tension load
rating for the
braided or solid wire to prevent failure of the communication line. In some
aspects of
the present disclosure, failure such as that described above may be presented
through
the non-linear coupling method to combine the braided or solid wire with the
communication line. in some implementations, the diameter of the downhole
cable
110 is about 0.138 inches.
[0047] FIGS. 2A-2B illustrate an example embodiment of a downhole cable
200 that manages strain on components of the cable 200. In some aspects, the
cable
200 can be used as or in place of the cable 110 described in FIG. 1. FIG. 2A
is a cross
sectional side view of a portion of the downhole cable 110. FIG. 2B is a cross
sectional top view of the downhole cable 200. Generally, as with the downhole
cable
110, the downhole cable 200 can support a downhole tool string (e.g., one or
more
downhole tools). The downhole cable 200 includes a braided. wire (ex.,
multiple
bound, or intertwined, wires such as wireline or electric line) or solid wire
(e.g., a
single wire such as slickline) and a communication line. The communication
line is
coupled with the braided or solid wire such as, for example, embedded in,
intertwined
with one or more wires, or wrapped around or within one or more wires, in a
non-
linear (e.g., undulating, helical, zig-zag, or otherwise) configuration.
[0048] In one example of the downhole cable 200, as shown in FIG. 2A,
the
downhole cable 200 is a slickline that includes a wire 210. 'The wire 210 can
be
formed from a metallic or non-metallic material, such as a composite material
(e.g.,
polyphenylene sulfide or other organic polymer, high-performance
thermoplastic, or
otherwise). The wire 210 is configured to couple to and support a downhole
tool
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string, such as the downhole tool string 120 of FIG. 1. The downhole cable 200
further includes a communication line 220 that is non-linearly coupled with
the wire
210. The communication line 220 can be sized to communicate instructions that
include logic and/or data to the downhole tool. The communication line 220 can
be
configured to elongate based on an axial force acting on the cable 200 that
relate, for
example, to the mass, acceleration, and/or the deceleration of the downhole
tool.
[0049] In some
implementations, the communication line 220 includes at least
one of a fiber optic cable or a metallic conductor wire. For example, when
communication and/or telemetry with the downhole tool use optical signals, the
communication line 220 includes one or more fiber optic cables. When
communication and/or telemetry with the downhole tool use electrical signals,
the
communication line 220 includes one or more metallic conductor wires.
[0050] The
communication line 220, in the illustrated example, is non-linearly
embedded in a matrix of the composite material of the wire 210. For example,
the
composite material may include metallic alloys, polymers, composites, and/or
other
materials. In manufacture, the communication line 220 can be continuously fed
into
the forming of the wire 210, which may be extruded or rolled or otherwise
formed.
The communication line 220 can be non-linearly embedded in the matrix of the
composite material in a helical (or spiral), zig-zag, sinusoidal, or other non-
linear
path. A helical path may be defined with a constant pitch and radius. A spiral
path
may be defined with a variable pitch and/or a variable radius. A zig-zag or
sinusoidal
path may be planar or three-dimensional. Other non-linear path benefiting
manufacture or strain management may also be used. As illustrated in FIG. 2A,
the
communication. line 220 is embedded in the wire 210 in a helical path. In FIG.
2B,
the helical path is further depicted with a constant or near constant radius.
[0004] FIGS. 3A-3B
illustrate example embodiments of a downhole cable 300
that manages strain on components of the conduit. In some aspects, the cable
300 can
be used as or in place of the cable 110 described in FIG. 1. FIG. 3.A is a
side view of
a portion of the downhole cable 300. FIG. 3B is a compressed cross sectional
top
view of the downhole cable 300. Generally, as with the downhole cables 110 and
200,
the downhole cable 300 can support a downhole tool string (e.g., one or more
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downhole tools). The downhole cable 300 includes a braided wire (e.g.,
multiple
bound, or intertwined, wires such as wireline or electric line) or solid wire
(e.g., a
single wire such as slickline) and a communication line. The communication
line is
coupled with the braided. or solid wire such as, for example, embedded in,
intei twined
with one or more wires, or wrapped around or within one or more wires, in a
non-
linear (e.g., undulating, helical, zig-zag, or otherwise) configuration.
[0051] Similar to
the embodiment disclosed in FIG. 2A, in FIG. 3A, the
downhole cable 300 may be coupled with a downhole tool string. The downhole
cable 300, in this example implementation, may be a slickline that includes a
wire
310, a communication line 320, and a coating 315. The communication line 320
can
be respectively similar to the communication line 220 as discussed in FIGS. 2A-
2B.
In this example, the wire 210 includes (e.g., is made of) a composite material
that
forms a flexible rod. The communication line 320 can non-linearly wrap around
the
flexible rod, such as in a helical manner. In FIG. 3B, the coating 315 can at
least
partially cover the communication line 320 and the flexible rod and can
protect the
communication line 320 from damaee and/or contamination. The coating 315 may
be
made of various thermoset, thermoplastic, or other polymer materials. In some
implementations, the coating 315 includes polyether ether ketone.
[0052] In both
configuration embodiments illustrated in FIGS. 2A and 3A, for
a particular portion of the downhole cables 200 and/or 300, the length of the
communication line 220 or 320 that extends between ends (or generally, two
points)
of the particular portion can be greater than the length of the wire 210 or
310
(respectively) that extends between the ends (or the two points) of the
particular
portion. For example, the helical configuration of the communication line 220
or 320
can be straightened during extension without incurring substantial tensile
strain. The
communication line 220 or 320 may respectively be allowed to move relative to
the
composite materials of the wire 210 or 310 during extension.
[0005] FIG. 4
illustrates an example method perfonned with a downhole
cable. At 402, a downhole tool is run into a wellbore from a terranean. The
downhole tool is coupled with the conduit. The downhole cable includes a
slickline
that includes a composite material, and a communication line non-linearly
coupled
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with the composite material. The communication line can be used to communicate
control or data information between the downhole tool and computing systems at
the
terranean surface. For example, the communication line can include at least
one of a
fiber optic line, or a metallic conductor.
[0053] in some
implementations, the communication line is non-linearly
embedded in a matrix of the composite material, such as in a helical, spiral,
zig-zag,
sinusoidal, or other similar non-linear manner. In some implementations, the
downhole cable can include composite material that includes a flexible rod;
and the
communication line is non-linearly wrapped around the flexible rod. The
downhole
cable can further include a coating that partially covers the communication
line and
the flexible rod.
[0054] At 404,
data signals are transmitted on the communication line within
the downhole cable. For example, the data signals can include logic or data
between
the downhole tool and the terranean surface. The logic or data can include
values
associated with telemetry data. In some implementations, the data signals can
be
optical signals sent from optical sensors of the downhole tool. In some
implementations, the data signals can be electrical signals sent from
electronic devices
and sensors. The data signals can also include control signals sent from the
terranean
surface. Close loop control may also be implemented using the communication
line.
[0055] At 406, the
downhole tool can be operated corresponding to the data
signals. For example, the downhole tool can perform certain functions based on
a
control instruction sent from the terranean surface. The operation of the
downhole
tool may increase or decrease the tension applied to the downhole cable.
[0056] At 408, a
force is received on the downhole cable. The force is related
to the tension in the downhole cable. The force may have been received at the
very
beginning of the operation. Discussing the force in this step does not
indicate its
occurrence in timing or order. The force can be a dynamic tensile load related
to the
mass of the downhole tool and its acceleration/deceleration.
[0057] At 409, in
response to the received force, the communication line is
elongated from a substantially non-linear position toward a substantially
linear
position. For example, the elongation may include extending the communication
line
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from a helical, zig-zag, sinusoidal, or spiral position toward the
substantially linear
position. The substantially non-linear position can be the original unloaded
position
of the communication line with respect to the slickline. The substantially
linear
position can be the fully extended position in line with the slickline. For a
particular
portion of the downhole cable, a length of the communication line that extends
between ends of the particular portion can be greater than a length of the
slickline that
extends between the ends of the particular portion.
[0058] In some
implementations, a second force less than the received force is
received (e.g., during deceleration). In response
to the second force, the
communication line is shortened from the substantially linear position toward
the
substantially non-linear position.
[0059] A number of
examples have been described. Nevertheless, it will be
understood that various modifications may be made. For example, even though
the
illustrations in FIGS. 2A and 3A use respective helical embedment and helical
wrapping configurations with the slickline composite materials, other
configurations
are possible, such as zig-zag, spiral, sinusoidal, among others. The composite
material may include substance(s) other than polyphenylene sulfide or include
a
different material. In the embodiment of FIG. 3A, the coating 315 may also
include
substance(s) other than polyether ether ketone, or include a different
material.
Accordingly, other examples are within the scope of the following claims.
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