Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: Thixotropic Non-cementitious Thermal Grout and HDD or Trough
Product Line Methods of Application
TECHNICAL FIELD
[0001] The disclosure relates to the field of horizontal directional
drilling,
trenchless technology, trenches, and grouts for installation of pipe,
conduits, ducts,
utility lines, and other product lines underground or under obstacles, such as
a body
of water or roadways.
BACKGROUND
[0002] Installation of electrical lines or underground cables has
traditionally
involved pumping a concrete mix into the annular space around electrical lines
or
underground cables. The process is time sensitive because the concrete will
set.
For example, such concrete mixtures may set in about twelve (12) hours or
less.
Additionally, the concrete has air pockets or voids such that fill rates or
percentages
may typically be 50-60%, or even as low as 40%.
[0003] The standard or traditional cementitious grouts, e.g. those
comprising
Portland cement, do not flow well, have high or higher temperatures due to
heat of
hydration which may deform, e.g., a duct or other apparatus, and become solid
after
(and maybe even during) their installation. Further, these traditional
cementitious
grouts irreversibly "set" after a period of time, and may put impractical or
impossible
time constraints on installation projects. Moreover, the voids and air pockets
of the
traditional cementitious grouts are undesirable and detrimental to cables.
BRIEF SUMMARY
[0004] The present disclosure generally relates to embodiments of a
thixotropic, non-cementitious, thermal grout and applications or methods of
use of
the grout related to horizontal directional drilling, trenchless technology,
trenching,
and installation of pipe, conduits, ducts, utility lines, and other product
lines which
may, e.g., be in trenches, underground, or under obstacles, such as a body of
water
or roadways.
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[0005] The present disclosure relates to embodiments of a thixotropic non-
cementitious thermal grout for horizontal directional drilling ("HDD")
applications for
use with cables/conduits/ducts/product lines.
[0006] Additionally, the present disclosure relates to embodiments of a
thixotropic non-cementitious thermal grout for trenching applications for use
with
cables/conduits/ducts/product lines.
[0007] Additionally, the present disclosure relates to embodiments of
methods
of installing cables/conduits/ducts/product lines related to horizontal
directional
drilling, trenchless technology, and trenching.
[0008] Horizontal directional drilling (also referred to as "HDD") is a
sophisticated, trenchless technique/method used to install utilities, such as
natural
gas pipe lines, electric and many other infrastructural needs, including by
way of
example only pipe, conduit, or cable, under ground level and often under
obstacles.
[0009] As used herein the term "product line(s)" shall refer to a
conduit(s),
pipe(s), tubular(s), duct(s), casing(s), cable(s) and/or the like. As used
herein those
terms do not refer to oil and gas drilling and production. As used herein the
term
"frac" shall also refer to fracking or hydraulic fracturing.
BRIEF DESCRIPTION OF DRAWINGS
[0010] The embodiments may be better understood, and numerous objects,
features, and advantages made apparent to those skilled in the art by
referencing
the accompanying drawings. These drawings are used to illustrate only typical
embodiments of this invention, and are not to be considered limiting of its
scope, for
the invention may admit to other equally effective embodiments. The figures
are not
necessarily to scale and certain features and certain views of the figures may
be
shown exaggerated in scale or in schematic in the interest of clarity and
conciseness.
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Fig. 1 depicts a sectional schematic view of an exemplary embodiment of a
metal casing and metal line pipes containing cable during an installation or
pull-back
(or removal for maintenance) at or near a midpoint position with a thixotropic
non-
cementitious thermal grout filling a space or void.
Fig. 2 shows a schematic, sectional view of an exemplary embodiment of a
thixotropic non-cementitious thermal grout occupying a space or void between a
steel casing and steel line pipes/steel cable pipes containing cable.
Fig. 3 depicts a sectional schematic view of an exemplary embodiment of a
trough containing cable during an install (or removal for maintenance) at or
near a
midpoint position with a thixotropic non-cementitious thermal grout filling a
space or
void.
Fig. 4 shows a schematic, sectional view of an exemplary embodiment of a
thixotropic non-cementitious thermal grout occupying a space or voice between
cables/conduits/product lines and walls of a trench.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0011] The description that follows includes exemplary apparatus,
methods,
techniques, and instruction sequences that embody techniques of the inventive
subject matter. However, it is understood that the described embodiments may
be
practiced without these specific details.
[0012] A thixotropic non-cementitious thermal grout for HDD application
for
use with cables/conduits/ducts/product lines or a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines may have a very low viscosity and flow freely while being pumped or when
energy is being applied, have no heat of hydration, gel quickly or rest in a
hardened
state, after pumping stops or energy is removed/no longer added, and can
return to
low viscosity or be "re-liquefied" or "un-gelled" later by reapplying energy
to allow
removing, e.g., a duct in a casing, and/or a cable in a duct. Due to the non-
cementitious or non-setting nature of the thixotropic non-cementitious thermal
grout,
it is possible to remove ducts/pipes, etc. in the future, e.g., for
maintenance, or if
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there is a problem with the system. As a gel the thixotropic non-cementitious
thermal grout resists flowing or seeping through cracks in pipe, casing or
duct.
[0013]
Such a thixotropic non-cementitious thermal grout may have a thermal
resistivity about equal to or less than 75 C-cm/W wherein the thermal
resistivity
does not change or does not significantly change with time. As one example,
the
thermal resistivity may be about 63 C-cm/VV. As another example, the thermal
resistivity may be about 65 C-cm/VV. Preferably, a thixotropic non-
cementitious
thermal grout has a thermal resistivity which matches or substantially matches
the
thermal resistivity of the native soils of a project site. For example, native
soils of a
project site can often vary from 65 to 75 C-cm/W. Therefore, a formulation or
mix of
a thixotropic non-cementitious thermal grout depends upon the thermal
resistivity of
the native soils of a project site.
[0014]
Additionally, a thixotropic non-cementitious thermal grout may have an
electrical conductivity that can provide or facilitate cathodic protection of
a cable pipe
inside a steel casing. A thixotropic non-cementitious thermal grout may have a
relatively high pH (about or approximately pH 11 or higher, preferably about
pH 11-
12), which is preferable in mitigating corrosion or facilitating cathodic
protection of
steel pipelines/conduits/ducts/product lines. In the "gelled" or solid state,
the
thixotropic non-cementitious thermal grout may not seep through a crack in the
structure where the grout is located. A thixotropic non-cementitious thermal
grout
may not dry-out, i.e. it may always remain fully saturated or substantially
saturated.
Further, a thixotropic non-cementitious thermal grout may be used in or
approved for
use in environmentally sensitive areas. The density of a thixotropic non-
cementitious
thermal grout generally depends upon sand content and, by way of example only,
may preferably be about 97 pounds per cubic foot¨i.e. specific gravity of
about 1.6.
By way of example only, the density of a thixotropic non-cementitious thermal
grout
may be about 99 pounds per cubic foot.
[0015] A
thixotropic non-setting or non-cementitious thermal grout provides
improvements or advantages for cable installation and ampacity. By way of
example
only, there may be about an 8-10% increase in ampacity rating if a thixotropic
non-
cementitious thermal grout is added to a duct in a trenched installation. As
another
example, there may be about a 4-6% increase in ampacity rating if a
thixotropic non-
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cementitious thermal grout is added for an HDD installation. Even higher
percentage
increases to ampacity rating, whether, e.g., a trenched installation or a HDD
installation, may occur when cables/conduits/ducts/product lines are shorter
lengths
or distances. A high-density thixotropic non-cementitious thermal grout may
prevent
long-term duct deformation due to external hydrostatic pressure in a deep HDD.
Additionally, the grout may be injected into existing ducts¨either
transmission or
distribution¨to obtain rating increases or increment in lifetime expectancy of
electric
systems.
[0016] A thixotropic non-cementitious thermal grout may aid the
installation of
ducts in a casing.
[0017] A thixotropic non-cementitious thermal grout may also have
applications in transmission and distribution cable systems. For example, in
an HDD
with a casing, filling the volume or annular space or void between ducts or
pipe and
the casing will improve heat transfer, increasing cable rating. As an
additional
example, filling cable ducts with the grout before cable installation provides
buoyancy and permits longer pulls.
[0018] Figures 1-2 show a sectional schematic view of an exemplary
embodiment of an HDD rig or apparatus 11 on surface 17 pulling pipe 13
connected
to a metal casing 12 and metal line pipes 14 containing cable 16 during an
installation or pull-back (or removal for maintenance) under an obstacle 19
utilizing a
thixotropic non-cementitious thermal grout 10 filling a space or void 24
defined by
drilled or reamed walls 26. The exemplary embodiment of Fig. 1 also shows frac
tank 18, vacuum pump(s) 20, and ball valve(s) 22 which may be utilized as a
part of
the installation or pull-back process.
[0019] Figure 2 shows a schematic, sectional view of an exemplary
embodiment (not drawn to scale) of a volume of thixotropic non-cementitious
thermal
grout 10 occupying or filling the annular space or void between the inner
surface 12a
of metal, e.g. steel, casing 12 and the outer surface 14b of metal, e.g.,
steel, line
pipes/steel cable pipes 14, the steel line pipes/steel cable pipes 14
containing cable
16. Grout 10 may additionally and/or optionally occupy the annular space or
void
between the inner surface 14a of steel line pipe or duct 14 and cable 16. In
this
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figure, the volume of thixotropic non-cementitious thermal grout 10 is
indicated by
symbols/hatching.
[0020]
Figure 3 shows a sectional schematic view of an exemplary
embodiment of a trough 112 containing conduit 114 containing cable during an
install
(or removal for maintenance) with a thixotropic non-cementitious thermal grout
110
filling a space or void.
[0021]
Figure 4 shows a schematic, sectional view of an exemplary
embodiment (not drawn to scale) of a volume of thixotropic non-cementitious
thermal
grout 110 occupying or filling a space or void between
cables/conduits/ducts/product
lines 114 and the walls 112a, 112b, 112c of a trench 112. Grout may
additionally
and/or optionally occupy the annular space or void between conduit 114 and
cable
116.
Referring to Figure 3, in this embodiment, the thixotropic non-cementitious
thermal grout 110 is not filling the entire trench 112. In this figure, the
volume of
thixotropic non-cementitious thermal grout 110 is indicated by
symbols/hatching.
[0022]
Empty conduits 15, 115 are represented in Figures 2 and 4. The
empty conduits 15, 115 could commonly be used for fiber optics installation
(fiber
optics used for data transmission). Alternatively, the empty conduits 15, 115
could
have another use as spare conduit(s) in case of the failure of the primary
conduit(s).
If used to replace a primary conduit due to a system failure conduit(s) 15
and/or 115
can be filled with thixotropic non-cementitious thermal grout 10 and/or 110 at
the
moment or time of installing a cable there-through.
[0023] In
one exemplary embodiment, a thixotropic non-cementitious thermal
grout for HDD applications for use with cables/conduits/ducts/product lines
may
comprise a volume of sand, a volume of water, a volume of bentonite
viscosifier, a
volume of at least one bentonite extender, a volume of lubricant, and a volume
of
soda ash.
[0024] In
one exemplary embodiment, a thixotropic non-cementitious thermal
grout 10 for HDD applications, as in Fig. 2, for use with
cables/conduits/ducts/product lines 12, 14, 16 may comprise a volume of frac
sand
at about 1629 lb/yd3, a volume of water at about 982 lb/yd3, a volume of
bentonite
viscosifier at about 43.5 lb/yd3, a volume of at least one bentonite extender
at about
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10.3 lb/yd3, a volume of lubricant at about 4.0 lb/yd3, and a volume of soda
ash at
about 7.6 lb/yd3.
[0025] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for HDD applications for use with cables/conduits/ducts/product lines
may have
a thermal resistivity of about equal to or less than 75 C-cm/W.
[0026] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for HDD applications for use with cables/conduits/ducts/product lines
may have
a pH of at least about 11.
[0027] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for HDD applications for use with cables/conduits/ducts/product lines
may have
a pH in the range of about 11 ¨12.
[0028] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for HDD applications for use with cables/conduits/ducts/product lines
may
further comprise a second bentonite extender. By way of example only, the
second
bentonite extender may further comprise a mixed metal oxide.
[0029] In one exemplary embodiment of a thixotropic non-cementitious
thermal grout for HDD applications for use with cables/conduits/ducts/product
lines,
the volume of sand may be a flaked frac sand.
[0030] In one exemplary embodiment of a thixotropic non-cementitious
thermal grout for HDD applications for use with cables/conduits/ducts/product
lines,
the frac sand may be #100 frac sand (e.g., but not limited to, white). Such a
frac
sand is commercially available from Erna Frac Sand, and US Silica.
[0031] In one exemplary embodiment of a thixotropic non-cementitious
thermal grout for HDD applications for use with cables/conduits/ducts/product
lines,
the volume of bentonite viscosifier may be MAX-GEL. MAX-GEL, brand/trademark
of M-I L.L.C., is an off-the-shelf bentonite viscosifier commercially
available from M-I
SWACO, a Schlumberger Company. Generically MAX-GEL may be a viscosifier
and namely a premium 220-bbl yield Wyoming bentonite blended with special
extender. The viscosifier is capable of yielding more than twice as much
viscosity as
regular Wyoming bentonite.
[0032] In one exemplary embodiment of a thixotropic non-cementitious
thermal grout for HDD applications for use with cables/conduits/ducts/product
lines,
the volume of at least one bentonite extender may be DRILPLEX. DRILPLEX,
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brand/trademark of M-I L.L.C., is an off-the-shelf bentonite extender
commercially
available from M-I SWACO, a Schlumberger Company. Generically DRILPLEX may
be a bentonite extender and secondary shale stabilizer designed to give
improved
carrying capacity and suspending ability in water-base drilling fluids, and/or
a mixed
metal oxide (MMO) or contains same.
[0033] In one exemplary embodiment of a thixotropic non-cementitious
thermal for HDD applications for use with cables/conduits/ducts/product lines,
the
volume of lubricant is RODEASE. RODEASE, brand/trademark of M-I L.L.C., is an
off-the-shelf lubricant commercially available from M-I SWACO, a Schlumberger
Company.
[0034] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout 110 for trenching applications, as in Fig. 4, for use with
cables/conduits/ducts/product lines 114, 116 may comprise a volume of sand, a
volume of water, a volume of bentonite viscosifier, a volume of at least one
bentonite
extender, a volume of lubricant, and a volume of soda ash. Generically RODEASE
may be a lubricant.
[0035] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for trenching applications for use with cables/conduits/ducts/product
lines may
comprise a volume of frac sand at about 1629 lb/yd3, a volume of water at
about 982
lb/yd3, a volume of bentonite viscosifier at about 43.5 lb/yd3, a volume of at
least one
bentonite extender at about 10.3 lb/yd3, a volume of lubricant at about 4.0
lb/yd3,
and a volume of soda ash at about 7.6 lb/yd3.
[0036] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for trenching applications for use with cables/conduits/ducts/product
lines may
have a thermal resistivity of about 63 C-cm/W.
[0037] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for trenching applications for use with cables/conduits/ducts/product
lines may
have a pH of at least about 11.
[0038] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for trenching applications for use with cables/conduits/ducts/product
lines may
have a pH in the range of about 11 ¨ 12.
[0039] In one exemplary embodiment, a thixotropic non-cementitious
thermal
grout for trenching applications for use with cables/conduits/ducts/product
lines may
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further comprise a second bentonite extender. In one exemplary embodiment, the
second bentonite extender may further comprise a mixed metal oxide.
[0040] In
one exemplary embodiment of a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines, the volume of sand may be a flaked frac sand.
[0041] In
one exemplary embodiment of a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines, the frac sand may be #100 frac sand (e.g., but not limited to, white).
[0042] In
one exemplary embodiment of a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines, the volume of bentonite viscosifier may be MAX-GEL.
MAX-GEL,
brand/trademark of M-I L.L.C., is an off-the-shelf bentonite viscosifier
commercially
available from M-I SWACO, a Schlumberger Company.
[0043] In
one exemplary embodiment of a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines, the volume of at least one bentonite extender may be DRILPLEX.
DRILPLEX,
brand/trademark of M-I L.L.C., is an off-the-shelf bentonite extender
commercially
available from M-I SWACO, a Schlumberger Company.
[0044] In
one exemplary embodiment of a thixotropic non-cementitious
thermal grout for trenching applications for use with
cables/conduits/ducts/product
lines, the volume of lubricant is RODEASE. RODEASE, brand/trademark of M-I
L.L.C., is an off-the-shelf lubricant commercially available from M-I SWACO, a
Schlumberger
Company.
[0045]
Related to horizontal directional drilling, trenchless technology, and
trenching, one exemplary embodiment of a method of installing
cables/conduits/ducts/product lines comprises the steps of filling a void or
space with
a thixotropic non-cementitious thermal grout, and pulling a product line
through the
grout. The steps of filling and pulling may occur in any sequence, order,
and/or at
the same time/simultaneously (in other words the thixotropic non-cementitious
thermal grouting may occur in new installations after drilling before product
line is
moved in, or by filling as one goes along with the product line; or product
line can be
moved in/out of existing installations, e.g. even installations many months or
years
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old as the grout 10/110 continues to flow freely long after it is first
installed). Further,
the grout may have a greater than 80% fill rate or percentage, and preferably
99% or
higher fill rate or percentage, or wherein greater than 80% of the desired
space or
void to be filled contains grout (as opposed to undesirable air pockets or
voids or
spaces in the grout). A void or space to be filled may be, by way of example
only, an
annular space or void, or a trench or a portion of a trench, or the space or
void of a
conduit, duct, casing, or product line. By way of example only, it is
preferred, for
example, that there is minimal air trap or minimal large pockets of air
localized within,
e.g. the entire conduit after grouting work is completed. This has the
advantages of
improving heat dissipation or thermal conductivity from cable to the earth and
improving electrical conductivity. As mentioned above the air pockets inhibit
same,
and this problem may be time sensitive in nature. Without gaps or air pockets
heat
may dissipate directly from cable, grout, conduit, grout, to earth. Filling
the casing
pipe with the thixotropic non-cementitious thermal grout has an electrical
conductivity
much greater than that of the surrounding earth and makes cathodically
protecting
the cable pipe more feasible than prior art pipe-within-a-pipe applications.
Electrical
resistivity of the thixotropic non-cementitious thermal grout (e.g. 325 Ohm-
cm) is
about twenty times lower than that of the native soil (e.g. 6925 Ohm-cm at 22%
moisture content), i.e. electrical conductivity is twenty times greater. This
makes it
possible to cathodically protect the pipe inside the casing in several
different
manners (by bare casing with conventional impressed current system on the
cable
pipe; by bare casing used as anode; by coating the outside of the casing used
as the
anode; or by impressed current 'ribbon' anode). This may enable the added
advantage of increasing amperage and, therefore, utilizing smaller cable
(lighter
weight) for pulls and maintenance, and/or less cable splicing may be required
for
longer distance pulls.
[0046] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines utilizes a thixotropic non-cementitious
thermal
grout comprising a volume of sand, a volume of water, a volume of bentonite
viscosifier, a volume of at least one bentonite extender, a volume of
lubricant, and a
volume of soda ash.
[0047] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines utilizes a thixotropic non-cementitious
thermal
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grout comprising a volume of frac sand at about 1629 lb/yd3, a volume of water
at
about 982 lb/yd3; a volume of bentonite viscosifier at about 43.5 lb/yd3; a
volume of
at least one bentonite extender at about 10.3 lb/yd3; a volume of lubricant at
about
4.0 lb/yd3; and a volume of soda ash at about 7.6 lb/yd3.
[0048] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines may comprise the steps of agitating the
thixotropic non-cementitious thermal grout to un-gel or unsolidify the
thixotropic non-
cementitious thermal grout and pulling the cable/conduit/duct/product line out
through the grout.
[0049] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines may comprise the steps of surrounding the
cable/conduit/duct/product line with the grout and inhibiting corrosion of
metal, the
grout having a pH in the range of about 11-12. Although an unexpected result
to
those skilled in the art (i.e. it is counterintuitive for a pH within the
range of about 11-
12 to be advantageous for inhibiting the corrosion of metal such as steel),
the
bentonite extender or DRILPLEX may be useful for same.
[0050] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines may comprise the step of surrounding the
product line with the grout, the grout having a thermal resistivity of about
equal to or
less than 75 C-cm/VV.
[0051] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines may comprise the step of surrounding the
product line with grout, the grout having an improved electrical conductivity
or
electrical resistivity of about 325 Ohm-cm.
[0052] In one exemplary embodiment, a method of installing
cable/conduits/ducts/product lines may further comprise the step of the grout
effluxing for fifteen seconds.
[0053] In one exemplary embodiment, a method of installing
cables/conduits/ducts/product lines may further comprise the step of removing
air
pockets from the grout during the filling or surrounding step. By way of
example
only, the thixotropic non-cementitious thermal grout 10/110 could be pumped
into the
11
bottom or low point of void(s), holes or troughs to be filled, pushing the air
out (i.e.
toward high points). Vacuum pumps and stand pipes may be useful for same.
[0054] Working Example:
In one working example referring to Figs. 1 & 2 a ball valve or valves 22 may
be
connected to a conduit 14 or casing 12 to be filled with the thixotropic non-
cementitious thermal grout 10. A frac tank 18 may be connected proximate the
entrance and/or exit to supply the thixotropic non-cementitious thermal grout
10.
Vacuum pump(s) 20 are also connected to the conduit 14 or casing 12 to be
filled.
Vacuum pump(s) 20 are turned on to pull, by way of example only, a vacuum
pressure of -10 psi atmospheric pressure. Specific ball valve(s) 22 (or ball
valve(s) in
combination with rotating devices) may then be opened to allow the thixotropic
non-
cementitious thermal grout 10 to flow gravitationally (the grout 10 flows
freely) into
the conduit 14 or casing 12 utilizing the volume stored in the frac tank 18
until the
conduit 14 or casing 12 is filled completely or as desired. Some of the vacuum
pressure may be lost during this step or as the conduit 14 or casing 12 is
filled. If
needed the vacuum pump(s) 20 may be reactivated to pump remaining thixotropic
non-cementitious thermal grout 10 as needed into the conduit 14 or casing 12
until
filled. Next, connect the electric cable pulling head to a swivel connected to
pulling
rig and reel, and for installation pull the electric cable 16 into the
thixotropic non-
cementitious thermal grout 10 in conduit 14 or casing 12. Then, optionally or
if ever
to be maintained, the electric cable 16, conduits 14 and/or casing 12 may be
removed.
[0056] It is understood that the present disclosure is not limited to the
particular applications and embodiments described and illustrated herein, but
covers
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all such variations thereof as come within the scope of the claims. While the
embodiments are described with reference to various implementations and
exploitations, it will be understood that these embodiments are illustrative
and that
the scope of the inventive subject matter is not limited to them. Many
variations,
modifications, additions and improvements are possible.
[0057]
Plural instances may be provided for components, operations or
structures described herein as a single instance. In
general, structures and
functionality presented as separate components in the exemplary configurations
may
be implemented as a combined structure or component. Similarly, structures and
functionality presented as a single component may be implemented as separate
components.
These and other variations, modifications, additions, and
improvements may fall within the scope of the inventive subject matter.
[0058]
The reference numbers in the claims are not intended to be limiting in
any way nor to any specific embodiment represented in the drawings, but are
included to assist the reader in reviewing the disclosure for purposes of a
provisional
filing.
13
