U.S. patent application number 15/214703 was filed with the patent office on 2016-11-10 for torque-balanced, gas-sealed wireline cables.
The applicant listed for this patent is Schlumberger Technology Corporation. Invention is credited to Sheng Chang, Byong Jun Kim, Joseph Varkey, Jushik Yun.
Application Number | 20160329128 15/214703 |
Document ID | / |
Family ID | 42980149 |
Filed Date | 2016-11-10 |
United States Patent
Application |
20160329128 |
Kind Code |
A1 |
Varkey; Joseph ; et
al. |
November 10, 2016 |
TORQUE-BALANCED, GAS-SEALED WIRELINE CABLES
Abstract
A torque-balanced, gas-blocking wireline cable and a method of
making the cable includes an electrically conductive cable core for
transmitting electrical power and surrounding inner and outer
layers of a plurality of armor wires. Gas blocking is achieved by
placing a soft polymer layer over the core before the inner wires
are cabled thereon. The inner wires imbed partially into the soft
polymer layer such that no gaps are left between the inner wires
and the core. A second soft polymer layer is optionally extruded
over the inner wires before the outer wires are applied. The second
soft polymer layer fills any spaces between the inner and outer
wire layers and prevents pressurized gas from infiltrating between
the wires. The inner wires have larger diameters than the outer
wires such that the inner wires carry approximately 60% of the load
and torque imbalance is prevented.
Inventors: |
Varkey; Joseph; (Sugar Land,
TX) ; Chang; Sheng; (Sugar Land, TX) ; Kim;
Byong Jun; (Sugar Land, TX) ; Yun; Jushik;
(Sugar Land, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schlumberger Technology Corporation |
Sugar Land |
TX |
US |
|
|
Family ID: |
42980149 |
Appl. No.: |
15/214703 |
Filed: |
July 20, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12425439 |
Apr 17, 2009 |
9412492 |
|
|
15214703 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01B 7/285 20130101;
H01B 13/24 20130101; H01B 7/046 20130101; Y02A 30/14 20180101; H01B
7/1895 20130101; Y10T 29/49117 20150115; H01B 13/02 20130101 |
International
Class: |
H01B 7/04 20060101
H01B007/04; H01B 13/02 20060101 H01B013/02; H01B 13/24 20060101
H01B013/24; H01B 7/285 20060101 H01B007/285; H01B 7/18 20060101
H01B007/18 |
Claims
1. A cable, comprising: an electrically conductive cable core for
transmitting electrical power; a first layer of polymer material
surrounding said cable core; an inner layer of a plurality of first
armor wires surrounding said cable core, said first armor wires
being imbedded in said first layer to prevent gaps between said
first armor wires and said cable core; and an outer layer of a
plurality of second armor wires surrounding said inner layer, said
second armor wires having a smaller diameter than a diameter of
said first armor wires for preventing torque imbalance in the
cable.
2. The cable of claim 1 wherein said first armor wires carry
approximately 60% of a load applied to the cable.
3. The cable of claim 1 including a second layer of polymer
material surrounding said inner layer, said outer layer surrounding
said second layer.
4. The cable of claim 3 including a third layer of polymer material
surrounding said outer layer.
5. The cable of claim 1 wherein said second armor wires are
stranded wires.
6. The cable of claim 1 wherein said polymer material of said first
layer is formed from at least one of: a polyolefin or olefin-base
elastomer material; a thermoplastic vulcanizate material; a
silicone rubber; an acrylate rubber; a soft engineering plastic; a
soft fluoropolymer material; a fluoroelastomer material; and a
thermoplastic fluoropolymer material.
7. The cable of claim 1 wherein said cable core includes another
polymer material having a higher melting point than a melting point
of said polymer material of said first layer.
8. A cable, comprising: an electrically conductive cable core for
transmitting electrical power; a first layer of polymer material
surrounding said cable core; an inner layer of a plurality of first
armor wires surrounding said cable core, said first armor wires
being imbedded in said first layer to prevent gaps between said
first armor wires and said cable core; a second layer of polymer
material surrounding said inner layer; and an outer layer of a
plurality of second armor wires surrounding said second layer, said
second layer preventing gaps between said first armor wires and
said second armor wires, said second armor wires having a smaller
diameter than a diameter of said first armor wires for preventing
torque imbalance in the cable.
9. The cable of claim 8 wherein said first armor wires carry
approximately 60% of a load applied to the cable.
10. The cable of claim 8 including a third layer of polymer
material surrounding said outer layer.
11. The cable of claim 8 wherein said second armor wires are
stranded wires.
12. The cable of claim 8 wherein said polymer materials of said
first and second layers are formed from at least one of: a
polyolefin or olefin-base elastomer material; a thermoplastic
vulcanizate material; a silicone rubber; an acrylate rubber; a soft
engineering plastic; a soft fluoropolymer material; a
fluoroelastomer material; and a thermoplastic fluoropolymer
material.
13. The cable of claim 8 wherein said cable core includes another
polymer material having a higher melting point than a melting point
of said polymer materials of said first and second layers.
14. A method of forming a cable, the method comprising: providing
an electrically conductive cable core for transmitting electrical
power; surrounding the cable core with a first layer of polymer
material; providing a plurality of first armor wires and winding
the first armor wires around the first layer to form an inner layer
of the first armor wires imbedded in the first layer to prevent
gaps between the first armor wires and the cable core; and
providing a plurality of second armor wires and winding the second
armor wires around the inner layer to form an outer layer of the
second armor wires, said second armor wires having a smaller
diameter than a diameter of said first armor wires for preventing
torque imbalance in the cable.
15. The method of claim 14 including extruding the first layer onto
the cable core.
16. The method of claim 14 including surrounding the inner layer
with a second layer of polymer material.
17. The method of claim 16 including surrounding the outer layer
with a third layer of polymer material.
18. The method of claim 17 including extruding the second layer
onto the inner layer and extruding the third layer onto the outer
layer.
19. The method of claim 14 including providing the cable core with
another polymer material having a higher melting point than a
melting point of the polymer material of the first layer.
20. The method of claim 14 including forming the second armor wires
as stranded wires.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a continuation application of U.S.
patent application Ser. No. 12/425,439, entitled: "Torque-Balanced,
Gas-Sealed Wireline Cables", filed on Apr. 17, 2009, the entirety
of which is incorporated herein by reference.
FIELD
[0002] Embodiments of the present disclosure generally relate to
downhole cables.
BACKGROUND
[0003] The statements in this section merely provide background
information related to the present disclosure and may not
constitute prior art.
[0004] The present disclosure relates generally to oilfield cables
and, in particular, to wireline cables, and methods of making and
using such cables.
[0005] Several common problems encountered with wireline cables
used in oilfield operations are related to armor wire strength
members. Armor wire is typically constructed of cold-drawn plow
ferritic steel coated with a zinc coating for corrosion protection.
These armor wires provide the strength needed to raise and lower
the weight of the cable and tool string and protect the cable core
from impact and abrasion damage. Typical wireline cable designs
consist of a cable core of one or more insulated conductors (packed
in an interstitial filler in the case of multiple conductors)
wrapped in cabling tape followed by the application of two armor
wire layers. The armor wire layers are applied counterhelically to
one another in an effort to minimize torque imbalance between the
layers. In an effort to provide additional protection against
impact, cut through, and abrasion damage, larger-diameter armor
wires are typically placed in the outer layer. Due to shortcomings
in these designs, torque imbalance between the armor wire layers
continues to be an issue, resulting in cable stretch, cable core
deformation and significant reductions in cable strength.
[0006] In pressurized wells, gas can infiltrate through gaps
between the armor wires and travel along spaces existing between
the inner armor wire layer and the cable core. Grease-filled pipes
at the well surface provide a seal at the well surface. As the
wireline cable passes through these pipes, pressurized gas can
travel through the spaces among armor wires and the cable core.
When the cable then passes over and bends over a sheave, the gas is
released, resulting in an explosion and fire hazard.
[0007] In typical wireline cable designs, such as a wireline cable
10 shown in FIG. 1, outer armor wires 11 were sized larger than
inner armor wires 12 in an effort to provide greater protection
against impact, cut-through, and abrasion damage. One unintended
effect of this design strategy is to increase torque imbalance. In
those designs, the outer armor wires 11 carry roughly 60% of the
load placed on the cable. This causes the outer armor wires 11 to
straighten slightly when the cable is under tension, which in turn
causes the cable core 13 to stretch and the inner armor wires 12 to
be wound more tightly around the cable core. The outer armor wires
11 and inner armor wires 12 may come into point-to-point contact
which wears away the protective zinc layer leading to premature
corrosion. The cable core 13 can also be damaged as it deforms into
the interstitial spaces between the inner armor wires 12.
Additionally, because the outer armor wires 11 are carrying the
bulk of the load, they are more susceptible to breaking if damaged,
thereby largely negating any benefits of placing the larger armor
wires in the outer layer.
[0008] Under tension, the inner and outer armor wires (which are
applied at opposite lay angles) tend to rotate in opposite
directions as shown by arrows 14 and 15 respectively as shown in
FIG. 1. Because the larger outer armor wires 11 are dominant, the
outer armor wires tend to open, while the inner armor wires 12
tighten, causing torque imbalance problems. To create a
torque-balanced cable, the inner armor wires would have to be
somewhat larger than the outer armor wires. This configuration has
been avoided in standard wireline cables in the belief that the
smaller outer wires would quickly fail due to abrasion and exposure
to corrosive fluids. Therefore, larger armor wires have been placed
at the outside of the wireline cable, which increases the
likelihood and severity of torque imbalance.
[0009] Torque for a layer of armor wire can be described in the
following equation.
Torque=1/4 T.times.PD.times.sin 2.alpha.
[0010] Where: T=Tension along the direction of the cable; PD=Pitch
diameter of the armor wires; and .alpha.=Lay angle of the
wires.
[0011] Pitch diameter (the diameter at which the armor wires are
applied around the cable core or the previous armor wire layer) has
a direct effect on the amount of torque carried by that armor wire
layer. When layers of armor wire constrict due to cable stretch,
the diameter of each layer is reduced numerically the same. Because
this reduction in diameter is a greater percentage for the inner
layer of armor wires 12, this has a net effect of shifting a
greater amount of the torque to the outer layer of armor wires
11.
[0012] In high-pressure wells, the wireline 10 is run through one
or several lengths of piping 16 packed with grease to seal the gas
pressure in the well while allowing the wireline to travel in and
out of the well (see FIG. 2). Armor wire layers have unfilled
annular gaps between the armor wire layers and the cable core.
Under well conditions, well debris and the grease used in the
risers can form a seal over the armor wires, allowing pressurized
gas to travel along the cable core beneath the armor wires.
Pressurized gas from the well can infiltrate through spaces between
the armor wires and travel upward along the gaps between the armor
wires and the cable core upward toward lower pressure. Given cable
tension and the sealing effects of grease from the risers and
downhole debris coating the armor wire layers, this gas tends to be
held in place as the wireline travels through the grease-packed
risers. As the wireline 10 bends when passing over the upper sheave
17 (located above the risers), the armor wires tend to spread apart
slightly and the pressurized gas 18 is released. This released gas
18 becomes an explosion hazard (see FIG. 3).
[0013] It is desirable, therefore, to provide a cable that
overcomes the problems encountered with wireline cable designs.
[0014] The disclosed designs minimize the problems described above
by:
[0015] Placing layers of soft polymer between the inner armor wires
and the cable core and between the inner and outer armor wire
layers; and
[0016] Using larger-diameter armor wires for the inner layer than
for the outer layer.
[0017] The polymeric layers provide several benefits,
including:
[0018] Eliminating the space along the cable core and the first
layer of armor along which pressurized gas might travel to escape
the well;
[0019] Eliminating the space into which the cable core might creep
and deform against the inner armor wires;
[0020] Cushioning contact points between the inner and outer armor
wires to minimize damage from armor wires rubbing against each
other;
[0021] Filling space into which the inner armor wire might
otherwise be compressed, thereby minimizing cable stretch; and
[0022] Filling space into which the inner armor wire might
otherwise be compressed, thereby minimizing the above-described
effect of shifting torque to the outer armor wire layer when the
diameters of both the inner and outer armor wire layers are
decreased by the same amount.
[0023] Torque balance is achieved between the inner and outer armor
wire layers by placing larger wires in the inner layer. As
explained below, this allows the majority of the load to be carried
by the inner armor wires. While in traditional armor wire
configurations, the outer wires ended up carrying approximately 60
percent of the load and the inner wires approximately 40 percent.
By placing the larger armor wires in the inner layer, the
proportions of load can be more or less reversed, depending on
individual cable design specifications.
[0024] The designs place soft thermoplastic polymer layers over the
cable core and between the inner and outer armor wire layers and
reconfigure the sizes of armor wires used such that larger armor
wires are placed in the inner layer. As an option, these designs
may utilize solid armor wires in the inner layer and stranded armor
wires in the outer layer. These design changes result in a more
truly torque-balanced cable that is sealed against intrusion and
travel of pressurized gas. These designs may also have an outer
layer of polymer to create a better seal at the well surface.
SUMMARY
[0025] An embodiment of a cable includes: an electrically
conductive cable core for transmitting electrical power; a first
layer of polymer material surrounding said cable core; an inner
layer of a plurality of first armor wires surrounding said cable
core, said first armor wires being imbedded in said first layer to
prevent gaps between said first armor wires and said cable core;
and an outer layer of a plurality of second armor wires surrounding
said inner layer, said second armor wires having a smaller diameter
than a diameter of said first armor wires for preventing torque
imbalance in the cable.
[0026] Another embodiment of a cable includes: an electrically
conductive cable core for transmitting electrical power; a first
layer of polymer material surrounding said cable core; an inner
layer of a plurality of first armor wires surrounding said cable
core, said first armor wires being imbedded in said first layer to
prevent gaps between said first armor wires and said cable core; a
second layer of polymer material surrounding said inner layer; and
an outer layer of a plurality of second armor wires surrounding
said second layer, said second layer preventing gaps between said
first armor wires and said second armor wires, said second armor
wires having a smaller diameter than a diameter of said first armor
wires for preventing torque imbalance in the cable. The first armor
wires can carry approximately 60% of a load applied to the cable.
The cable can include a third layer of polymer material surrounding
said outer layer. The second armor wires can be stranded wires. The
polymer materials of said first and second layers can be formed
from at least one of: a polyolefin or olefin-base elastomer
material; a thermoplastic vulcanizate material; a silicone rubber;
an acrylate rubber; a soft engineering plastic; a soft
fluoropolymer material; a fluoroelastomer material; and a
thermoplastic fluoropolymer material. The cable core can include
another polymer material having a higher melting point than a
melting point of said polymer materials of said first and second
layers.
[0027] A method of forming a cable includes: providing an
electrically conductive cable core for transmitting electrical
power; surrounding the cable core with a first layer of polymer
material; providing a plurality of first armor wires and winding
the first armor wires around the first layer to form an inner layer
of the first armor wires imbedded in the first layer to prevent
gaps between the first armor wires and the cable core; and
providing a plurality of second armor wires and winding the second
armor wires around the inner layer to form an outer layer of the
second armor wires, said second armor wires having a smaller
diameter than a diameter of said first armor wires for preventing
torque imbalance in the cable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] These and other features and advantages of the present
invention will be better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings wherein:
[0029] FIG. 1 is a radial cross-sectional view of a prior art
wireline cable;
[0030] FIG. 2 is a schematic cross-sectional view of the prior art
wireline cable shown in FIG. 1 in use;
[0031] FIG. 3 is an enlarged view of the prior art wireline cable
and the upper sheave shown in FIG. 2;
[0032] FIGS. 4A through 4D are radial cross-sectional views of a
first embodiment wireline mono cable;
[0033] FIGS. 5A through 5D are radial cross-sectional views of a
second embodiment wireline coaxial cable;
[0034] FIGS. 6A through 6D are radial cross-sectional views of a
third embodiment wireline hepta cable;
[0035] FIGS. 7A through 7D are radial cross-sectional views of a
fourth embodiment wireline hepta cable;
[0036] FIGS. 8A through 8D are radial cross-sectional views of a
fifth embodiment wireline hepta cable;
[0037] FIGS. 9A through 9D are radial cross-sectional views of a
sixth embodiment wireline hepta cable;
[0038] FIG. 10 is a radial cross-sectional view of a seventh
embodiment wireline cable;
[0039] FIG. 11 is a radial cross-sectional view of an eighth
embodiment wireline cable; and
[0040] FIG. 12 is a schematic representation of a manufacturing
line for constructing wireline cable.
DETAILED DESCRIPTION
[0041] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. It will of
course be appreciated that in the development of any such actual
embodiment, numerous implementation-specific decisions must be made
to achieve the developers specific goals, such as compliance with
system related and business related constraints, which will vary
from one implementation to another. Moreover, it will be
appreciated that such a development effort might be complex and
time consuming but would nevertheless be a routine undertaking for
those of ordinary skill in the art having the benefit of this
disclosure.
[0042] The present invention relates to a wireline cable that
utilizes soft polymers as interstitial fillers beneath and between
the armor wire layers, which soft polymers may be any suitable
material, including but not limited to the following: polyolefin or
olefin-base elastomer (such as Engage.RTM., Infuse.RTM., etc.);
thermoplastic vulcanizates (TPVs) such as Santoprene.RTM. and Super
TPVs and fluoro TPV (F-TPV); silicone rubber; acrylate rubber; soft
engineering plastics (such as soft modified polypropylene sulfide
(PPS] or modified Poly-ether-ether-ketone [PEEK]); soft
fluoropolymer (such as high-melt flow ETFE
(ethylene-tetrafluoroethylene) fluoropolymer; fluoroelastomer (such
as DAI-EL.TM. manufactured by Daikin); and thermoplastic
fluoropolymers.
[0043] The above polymers can be also used with various additives
to meet the mechanical requirement.
[0044] Armor wire strength members may be any suitable material
typically used for armor wires, such as: galvanized improved plow
steel (with a variety of strength ratings); high-carbon steel; and
27-7 Molybdenum. These may be used as solid armors or stranded
members.
[0045] Low-temperature polymers may be used for the polymeric
jacketing layers to enable the armoring process to be stopped
without damaging the cable core. This strategy, as discussed below,
requires that the "low-temperature" polymers have process
temperatures 25.degree. F. to 50.degree. F. below those used in the
cable core. Possible jacketing materials include: polyolefin-base
and acrylate-base polymers with process temperatures in ranging
from 300.degree. F. to 450.degree. F.; and fluoropolymer with lower
melting point.
[0046] The core polymers are chosen to have higher melting point
than the processing temperature of the polymers selected to fill
the space between the core and inner wire, and also the space
between inner armor and outer armor wires. This allows combining
the armoring and extrusion process at the same time to stop the
armoring process for troubleshooting when needed with no concerns
of getting melted and thermally degraded core polymers in the
extrusion crosshead.
[0047] The key to achieving torque balance between the inner and
outer armor wire layers is to size the inner armor wires
appropriately to carry their share of the load. Given the
likelihood that some minimal amount of stretch may occur, these
designs begin with the inner armor wires carrying slightly
approximately 60 percent of the load. Any minimal stretch that may
occur (which tends to shift load to the outer armor wires) will
therefore only tend to slightly improve torque balance between the
armor wire layers.
[0048] In a torque-balanced cable: Torque.sub.1=Torque.sub.o
[0049] Where: Torque.sub.i=Torque of the inner armor wires; and
Torque.sub.o=Torque of the outer armor wires.
[0050] Torque for a layer of armor wires in a wireline cable can be
measured by applying the following equation:
Torque=1/4 T.times.PD.times.sin 2.alpha.
[0051] Where: T=Tension along the direction of the cable; PD=Pitch
diameter of the armor wires; and .alpha.=Lay angle of the
wires.
[0052] The primary variable to be adjusted in balancing torque
values for armor wires applied at different circumferences is the
diameter of the wires. The lay angles of the inner and outer armor
wires are typically roughly the same, but may be adjusted slightly
to optimize torque values for different diameter wires. Because the
inner layer of wires has a smaller circumference, the most
effective strategy for achieving torque balance is for their
individual diameters to be larger than those in the outer layer.
Several sample embodiments of torque-balanced, gas-blocking
wireline cable designs are described below that apply these
principles. In no way do these examples describe all of the
possible configurations that can be achieved by applying these
basic principles.
[0053] A first embodiment is a 0.26.+-.0.02 inch diameter
mono/coaxial/triad or other configuration wireline cable with
torque balance and gas-blocking design (FIGS. 4A through 4D)--
[0054] For a mono/coaxial/triad or any other configuration wireline
cable 20 with a core diameter of 0.10-0.15 inch and a completed
diameter of 0.26.+-.0.02 inch, torque balance could be achieved
with inner armor wires 21 of 0.035-0.055 inch diameter and outer
armor wires 22 with diameters of 0.020-0.035 inch. The gas blocking
is achieved by placing a layer 23 of soft polymer (FIG. 4B) over
the cable core 24 (FIG. 4A) before the inner armor wires 21 are
cabled over the core (FIG. 4C). The inner armor wires 21 imbed
partially into the soft polymer layer 23 such that no gaps are left
between the inner armor wires and the cable core. A second layer 25
of soft polymer (FIG. 4C) is optionally extruded over the inner
armor wires 21 before the outer armor wires 22 are applied to the
cable (FIG. 4D). The second layer 25 of soft polymer fills any
spaces between the inner and outer armor wires layers and prevents
pressurized gas from infiltrating between the armor wires. By
eliminating space for the inner armor wires to compress into the
cable core 24, the cable 20 also significantly minimizes cable
stretching which helps to further protect the cable against
developing torque imbalance in the field. For the values given for
this cable, the inner armor wire layer 21 will carry approximately
60% of the load.
[0055] A second embodiment is a 0.32.+-.0.02 inch diameter
mono/coaxial/hepta or other configuration wireline cable with
torque balance and gas-blocking design (FIGS. 5A through 5D)--
[0056] For a mono/coaxial/hepta or any other configuration wireline
cable 30 with a core diameter of 0.12-0.2 inch and a completed
diameter of 0.32.+-.0.02 inch, torque balance could be achieved
with inner armor wires 31 of 0.04-0.06 inch diameter and outer
wires 32 with diameters of 0.02-0.04 inch. The gas blocking is
achieved by placing a layer 33 of soft polymer (FIG. 5B) over the
cable core 34 (FIG. 5A) before the inner armor wires are cabled
over the core. The inner armor wires 31 imbed partially into the
soft polymer layer 33 (FIG. 5C) such that no gaps are left between
the inner armor wires and the cable core 34. A second layer 35 of
soft polymer (FIG. 5D) is optionally extruded over the inner armor
wires 31 before the outer armor wires 32 are applied to the cable
30. The second layer 35 of soft polymer fills any spaces between
the inner and outer armor wires layers and prevents pressurized gas
from infiltrating between the armor wires. By eliminating space for
the inner armor wires to compress into the cable core 34, the cable
30 also significantly minimizes cable stretching which helps to
further protect the cable against developing torque imbalance in
the field. For the values given for this cable, the inner armor
wire layer 31 will carry approximately 60% of the load.
[0057] A third embodiment is a 0.38.+-.0.02 inch diameter
hepta/triad/quad or any other configuration wireline cable with
torque balance and gas blocking (FIGS. 6A through 6D)--
[0058] For a hepta/triad/quad or any other wireline cable 40
configuration with a core diameter of 0.24-0.29 inch and a
completed diameter of 0.38.+-.0.02 inch, torque balance could be
achieved with inner armor wires 41 of 0.04-0.06 inch diameter and
outer wires 42 with diameters of 0.025-0.045 inch. The gas blocking
is achieved by placing a layer 43 of soft polymer (FIG. 6B) over
the cable core 44 (FIG. 6A) before the inner armor wires 41 are
cabled over the core. The inner armor wires 41 imbed partially into
the soft polymer (FIG. 6C) such that no gaps are left between the
inner armor wires and the cable core 44. A second layer 45 of soft
polymer (FIG. 6D) is optionally extruded over the inner armor wires
41 before the outer armor wires 42 are applied to the cable 40. The
second layer 45 of soft polymer fills any spaces between the inner
and outer armor wires layers and prevents pressurized gas from
infiltrating between the armor wires. By eliminating space for the
inner armor wires 41 to compress into the cable core 44, the cable
40 also significantly minimizes cable stretching which helps to
further protect the cable against developing torque imbalance in
the field. For the values given for this cable, the inner armor
wire layer will carry approximately 60% of the load.
[0059] A fourth embodiment is a 0.42.+-.0.02 inch diameter
hepta/triad/quad or any other configuration wireline cable with
torque balance and gas blocking (FIGS. 7A through 7D)--
[0060] For a hepta/triad/quad or any other wireline cable 50
configuration with a core diameter of 0.25-0.30 inch and a
completed diameter of 0.42.+-.0.02 inch, torque balance could be
achieved with inner armor wires 51 of 0.04-0.06 inch diameter and
outer armor wires 52 with diameters of 0.025-0.045 inch. The gas
blocking is achieved by placing a layer 53 of soft polymer (FIG.
7B) over the cable core 54 (FIG. 7A) before the inner armor wires
51 are cabled over the core (FIG. 7C). The inner armor wires 51
imbed partially into the soft polymer layer 53 such that no gaps
are left between the inner armor wires and the cable core 54. A
second layer 55 of soft polymer (FIG. 7D) is optionally extruded
over the inner armor wires 51 before the outer armor wires 52 are
applied to the cable 50. The second layer 55 of soft polymer fills
any spaces between the inner and outer armor wires layers and
prevents pressurized gas from infiltrating between the armor wires.
By eliminating space for the inner armor wires 51 to compress into
the cable core 54, the cable 50 also significantly minimizes cable
stretching which helps to further protect the cable against
developing torque imbalance in the field. For the values given for
this cable, the inner armor wire layer will carry approximately 60%
of the load.
[0061] A fifth embodiment is a 0.48.+-.0.02 inch diameter
hepta/triad/quad or any other configuration wireline cable with
torque balance and gas blocking (FIGS. 8A through 8D)--
[0062] For a hepta/triad/quad or any other wireline cable 60
configuration with a core diameter of 0.20-0.35 inch and a
completed diameter of 0.48.+-.0.02 inch, torque balance could be
achieved with inner armor wires 61 of 0.05-0.07 inch diameter and
outer armor wires 62 with diameters of 0.03-0.05 inch. The gas
blocking is achieved by placing a layer 63 of soft polymer (FIG.
8B) over the cable core 64 (FIG. 8A) before the inner armor wires
61 are cabled over the core (FIG. 8C). The inner armor wires 61
imbed partially into the soft polymer layer 63 such that no gaps
are left between the inner armor wires and the cable core 64. A
second layer 65 of soft polymer (FIG. 8D) is optionally extruded
over the inner armor wires 61 before the outer armor wires 62 are
applied to the cable 60. The second layer 65 of soft polymer fills
any spaces between the inner and outer armor wires layers and
prevents pressurized gas from infiltrating between the armor wires.
By eliminating space for the inner armor wires 61 to compress into
the cable core 64, the cable 60 also significantly minimizes cable
stretching which helps to further protect the cable against
developing torque imbalance in the field. For the values given for
this cable, the inner armor wire layer will carry approximately 60%
of the load.
[0063] A sixth embodiment is a 0.52.+-.0.02 inch diameter hepta
cable with torque-balanced, gas-blocking design (FIGS. 9A through
9D)--
[0064] For a hepta cable 70 with a core diameter of 0.25-0.40 inch
and a completed diameter of 0.52.+-.0.02 inch, torque balance could
be achieved with inner armor wires 71 of 0.05-0.07 inch diameter
and outer armor wires 72 with diameters of 0.03-0.05 inch. The gas
blocking is achieved by placing a layer 73 of soft polymer (FIG.
9B) over the cable core 74 (FIG. 9A) before the inner armor wires
71 are cabled over the core (FIG. 9C). The inner armor wires 71
imbed partially into the soft polymer layer 73 such that no gaps
are left between the inner armor wires and the cable core 74. A
second layer 75 of soft polymer (FIG. 9D) is optionally extruded
over the inner armor wires 71 before the outer armor wires 72 are
applied to the cable 70. The second layer 75 of soft polymer fills
any spaces between the inner and outer armor wires layers and
prevents pressurized gas from infiltrating between the armor wires.
By eliminating space for the inner armor wires 71 to compress into
the cable core 74, the cable 70 also significantly minimizes cable
stretching which helps to further protect the cable against
developing torque imbalance in the field. For the values given for
this cable, the inner armor wire layer will carry approximately 60%
of the load.
[0065] A seventh embodiment includes an optional stranded wire
outer armoring (FIG. 10)--
[0066] As an option in any of the embodiments described above, the
outer layer of solid armor wires may be replaced with similarly
sized stranded wires 81 in a wireline cable 80 as shown in FIG. 10.
If a stranded wire is used on the outside, a jacket 82 is put over
the top of the stranded wires 81 and bonded to the inner jacket
between the stranded wires in order not to expose the small
individual elements directly to well bore conditions of abrasion
and cutting.
[0067] An eighth embodiment includes an outer, easily sealed
polymeric jacket (FIG. 11)--
[0068] To create torque-balanced, gas-sealed cables that are also
more easily sealed by means of a rubber pack-off instead of pumping
grease through flow tubes at the well surface, any of the above
embodiments may be provided with an outer polymeric jacket 91. To
continue the gas-sealed capabilities to the outer diameter of the
cable 90, this polymeric material must be bondable to the other
jacket layers. For example (as shown in FIG. 11), an outer jacket
91 of carbon-fiber-reinforced ETFE (ethylene-tetrafluoroethylene)
fluoropolymer may be applied over the outer armor wire layer 72,
bonding through the gaps in the outer strength members. This
creates a totally bonded jacketing system and with the addition of
the fiber-reinforced polymer, also provides a more durable outer
surface. For this, the polymer that is placed between the inner and
outer armor layers needs to bond to the jacket placed on top of the
outer armor wires 72 through the gap in the outer armor wires.
[0069] In any of the above-described embodiments, polymers for the
armor-jacketing layers may be chosen with significantly lower
process temperatures (25.degree. F. to 50.degree. F. lower) than
the melting point of polymers used in the cable core. This enables
the armoring process to be stopped and started during armoring
without the risk that prolonged exposure to extruding temperatures
will damage the cable core. This on-line process is as follows with
reference to a schematic representation of a wireline cable
manufacturing line 100 shown in FIG. 12:
[0070] A cable core 101 enters the armoring process line 100 at the
left in FIG. 12.
[0071] A layer of soft polymer 102 is extruded over the cable core
101 in a first extrusion station 103. The soft outer polymer allows
for better and more consistent embedding of the armor wires into
the polymer. In case that the cable core 101 needs to be protected
during the armoring process or harsh field operation, dual layers
of hard and soft polymers can be co-extruded over the cable core. A
hard polymer layer placed underneath a soft polymer layer is
mechanically resistant so that such a layer could prevent armor
wires from breaking into the cable core through the soft layer.
Alternatively this layer could be extruded prior to the armoring
process.
[0072] An inner armor wire layer 104 is cabled helically over and
embedded into the soft polymer 102 at a first armoring station 105.
While armoring, any electromagnetic heat source such as infrared
waves, ultrasonic waves, and microwaves may be used to further
soften the polymers to allow the armoring line 100 to be run
faster. This could be applied before the armor hits the core or
after the armor touches the core.
[0073] A second layer 106 of soft polymer is extruded over the
embedded inner layer 104 of armor wires at a second extrusion
station 107.
[0074] An outer armor wire layer 108 is cabled (counterhelically to
the inner armor wire layer 104) over and embedded into the soft
polymer 106 at a second armoring station 109. While armoring, any
electromagnetic heat source such as infrared waves, ultrasonic
waves, and microwaves maybe used to further soften polymers to
allow the armoring line 100 to be run faster. This could be applied
before the armor hits the core or after the armor touches the
core.
[0075] If needed, a final layer 110 of hard polymer is extruded
over the embedded outer armor wire layer 108 at a third extrusion
station 111 to complete the cable as described above.
[0076] Although the on-line combined process as described is
preferred to save a significant amount of manufacturing time, each
step of the process can be separated for accommodation of process
convenience.
[0077] The particular embodiments disclosed above are illustrative
only, as the invention may be modified and practiced in different
but equivalent manners apparent to those skilled in the art having
the benefit of the teachings herein. Furthermore, no limitations
are intended to the details of construction or design herein shown,
other than as described in the claims below. It is therefore
evident that the particular embodiments disclosed above may be
altered or modified and all such variations are considered within
the scope and spirit of the invention. In particular, every range
of values (of the form, "from about a to about b," or,
equivalently, "from approximately a to b," or, equivalently, "from
approximately a-b") disclosed herein is to be understood as
referring to the power set (the set of all subsets) of the
respective range of values. Accordingly, the protection sought
herein is as set forth in the claims below.
[0078] The preceding description has been presented with reference
to presently preferred embodiments of the invention. Persons
skilled in the art and technology to which this invention pertains
will appreciate that alterations and changes in the described
structures and methods of operation can be practiced without
meaningfully departing from the principle, and scope of this
invention. Accordingly, the foregoing description should not be
read as pertaining only to the precise structures described and
shown in the accompanying drawings, but rather should be read as
consistent with and as support for the following claims, which are
to have their fullest and fairest scope.
* * * * *