Note: Descriptions are shown in the official language in which they were submitted.
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APPLICATION FOR PATENT
Zonal Isolation Of Telescoping Perforation Apparatus With Memory
Based Material
Inventors: Edgar Van Sickle and Eugene Ratterman;
FIELD OF THE INVENTION
[0001] This invention is in the field of methods and apparatus for isolating
one
formation zone of an oil or gas well bore from another zone.
BACKGROUND OF THE INVENTION
[00021 It is common to drill an oil or gas well bore into and through several
different formation zones, where the zones are layered vertically. In such
cases, it is
typical to isolate each zone from the zones above and below it by installing a
packer in
the well bore between zones, surrounding a tubular element, such as production
piping,
which is used to access the various zones. Known systems for achieving this
isolation
commonly use inflatable or mechanically expandable packers. The inflated
packers can
be filled with various fluids or even cement. These types of packers can be
expensive,
and setting them in place can be complicated, since electrical or mechanical
systems are
usually required for the setting operation. These packers are also less
effective in open
hole applications than in cased hole applications, because they sometimes do
not truly
conform to the irregular walls of the open hole, resulting in a limited
pressure seal
capacity. The problems of expense and complexity are even greater in an
application
where numerous zones are being accessed by a multi-purpose tool having
numerous
perforation sections for production of fluid from the well or injection of
fluid into the
well. This is because numerous packers are required to isolate between zones,
and
because operation of the numerous perforation sections adds to the overall
complexity of
operating such a tool.
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BRIEF SUMMARY OF THE INVENTION
100031 The present invention is a method and apparatus for isolating between
zones with a packer. In the preferred embodiment the packer constructed of
memory
based material, such as a memory based foam, where the multiple zones are
accessed by
means of radially telescoping perforation elements. The memory based material
is
formed onto a base element, such as a mandrel or another tubular element, to
form a
packer with an outer diameter slightly larger than the downhole diameter in
which the
packer will be used. The packer is positioned between two sections of radially
telescoping perforation elements, in a downhole tool. Two or more packers can
be
arranged between three or more sections of radially telescoping perforation
elements.
The memory based material is compressed, such as by elevating a memory based
foam to
a temperature at which it begins to soften, sometimes called the transition
temperature,
and the outside diameter of the memory based material is reduced to a smaller
diameter,
such as by being compressed. Once compressed, the memory based material is
then
stabilized at that smaller diameter, such as by cooling a memory based foam
below the
transition temperature, causing it to harden at this desired, smaller, run-in
diameter.
Then, the tool is run into the hole on a tubular work string, placing each
packer at a depth
where zonal isolation is required, and placing each section of radially
telescoping
perforation elements at a depth where zonal access is required. Once each
packer is at its
respective required zonal isolation depth, the memory based material is then
expanded,
such as by raising a memory based foam above the transition temperature,
causing it to
tend to return to its original, larger, outer diameter. Since the original
diameter is larger
than the hole diameter, the packer conforms to the bore hole and exerts an
effective
pressure seal on the bore hole wall, between zones. As an alternative, the
mandrel or
other base element can be hollow, and it can be expanded either before,
during, or after
the temperature-induced expansion of the foam expansion element. This
expansion can
be achieved by a mechanical, hydraulic, or hydro-mechanical device. Expansion
of the
mandrel can enhance the overall expansion achieved with a given amount of
memory
based material expansion, and it can increase the resultant pressure exerted
by the
memory based expansion element on the borehole wall, thereby creating a more
effective
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seal. Different packers can be adapted to expand at different temperatures, or
through
other means adapted to expand at different selected times, as desired by the
operator. If
desired, cementing of the annulus can also be performed, in the normal
fashion. Other
alternatives to shape memory packers are envisioned for sealing producing
zones such as
mechanically or hydraulically set packers, inflatable packers, barriers made
of a
hardenable material and other designs used downhole to isolate one portion of
the
well-bore from another.
[0004] The novel features of this invention, as well as the invention itself,
will be
best understood from the attached drawings, taken along with the following
description,
in which similar reference characters refer to similar parts, and in which:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] Figure 1 is a perspective view of the preferred memory based packer
invention, in its originally formed size and shape and is intended to
schematically
illustrate the use of alternative barriers in the present invention;
[0006] Figure 2 is a perspective view of the apparatus shown in Figure 1,
reduced
to its interim size and shape;
[0007] Figure 3 is a perspective view of the apparatus shown in Figure 1,
expanded to seal against the borehole wall;
[0008] Figures 4 and 5 are partial section views of the memory based packer of
the present invention, implementing a hydro-mechanical device to expand the
mandrel;
[0009] Figures 6 and 7 are partial section views of the memory based packer of
the present invention, implementing a mechanical device to expand the mandrel;
[0010] Figure 8 is a partial section view of the memory based packer of the
present invention, implementing a hydraulic device to expand the mandrel;
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[0011] Figures 9 and 10 show a first embodiment of the invention incorporating
a
memory based packer with a telescoping perforation tool having a solid walled
shifting
sleeve, some sand control elements, and some fracturing elements;
[0012] Figures 11 and 12 show a second embodiment of the invention
incorporating a memory based packer with a telescoping perforation tool having
a shifting
sleeve incorporating a sand control medium, where none of the telescoping
elements have
a sand control medium;
[0013] Figures 13 and 14 show a third embodiment of the invention
incorporating
a memory based packer with a telescoping perforation tool having a shifting
sleeve with
ports, some sand control elements, and some fracturing elements; and
[0014] Figures 15 and 16 show a fourth embodiment of the invention
incorporating a memory based packer with a telescoping perforation tool having
a shifting
sleeve with some sand control ports, and some fracturing ports.
DETAILED DESCRIPTION OF THE INVENTION
[0015] As shown in Figure 1, the preferred packer for use in the present
invention
is a memory based packer 10 having a base element, such as a tubular element
or a
mandrel 20, on which is formed a memory based expansion element 30, such as an
element constructed of memory based foam. The mandrel 20 can be any desired
length or
shape, to suit the desired application, and it can be hollow if required. It
can also have
any desired connection features, such as threaded ends. The mandrel 20 can be
a portion
of the tubular body of the overall tool, or it can be a separate tubular
element. The
expansion element 30 is shown with a cylindrical shape, but this can be
varied, such as by
means of concave ends or striated areas (not shown), to facilitate deployment,
or to
enhance the sealing characteristics of the packer. The expansion element 30 is
composed
of a memory based material, for example, an elastic memory foam such as
TemboT'
foam, an open cell syntactic foam manufactured by Composite Technology
Development,
Inc. This type of foam has the property of being convertible from one size and
shape to
another size and/or shape, by changing the temperature of the foam. This type
of foam
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can be formed into an article with an original size and shape as desired, such
as a cylinder
with a desired outer diameter. The foam article thusly formed is then heated
to raise its
temperature to its transition temperature. As it achieves the transition
temperature, the
foam softens, allowing the foam article to be reshaped to a desired interim
size and shape,
such as by being compressed to form a smaller diameter cylinder. The
temperature of the
foam article is then lowered below the transition temperature, to cause the
foam article to
retain its interim size and shape. When subsequently raised again to its
transition
temperature, the foam article will return to its original size and shape.
[00161 In the present invention, the cylindrical memory based expansion
element
30 can be originally formed onto the mandrel 20 by wrapping a blanket of the
memory
based material onto the mandrel 20, with the desired original outer diameter
OD1.
Alternatively, the process for forming the expansion element 30 on the mandrel
20 can be
any other process which results in the expansion element 30 having the desired
original
diameter, such as by molding the memory based material directly onto the
mandrel 20.
The desired original outer diameter OD, is larger than the bore hole diameter
BHD
(shown for reference in Figure 1) in which the packer 10 will be deployed. For
instance,
an expansion element 30 having an original outer diameter OD1 of 10 inches
might be
formed for use in an 8.5 inch diameter borehole.
[0017] Then, the memory based packer is reduced in diameter, for example by
raising the temperature of the expansion element 30 above the transition
temperature of
the memory based foam material, which causes the foam to soften. At this
point, the
expansion element 30 is compressed to a smaller interim outer diameter OD2.
For
instance, the expansion element 30 might be compressed to an interim outer
diameter
ODZ of 7.5 inches for use in an 8.5 inch diameter borehole. This facilitates
running the
packer 10 into the borehole. This type of foam may be convertible in this way
to an
interim size and shape approximately one third the volume of the original size
and shape.
After compression, the expansion element 30 is lowered below its transition
temperature,
causing it to retain its smaller interim outer diameter OD2. This cooling step
can be
achieved by exposure to the ambient environment, or by exposure to forced
cooling.
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[0018] After this diameter reduction, the memory based packer 10 is lowered
into
the borehole to the desired depth at which zonal isolation is to occur, as
shown in Figure
2. Once the packer 10 is located at the desired depth for isolating the
borehole, the
expansion element 30 is again expanded, such as by being raised to the
transition
temperature of the foam. As shown in Figure 3, this causes the expansion
element 30 to
expand to a final outer diameter OD3. Because of the properties of the elastic
memory
foam, the expansion element 30 attempts to return to the original outer
diameter OD1.
However, since the original outer diameter OD, was selected to be larger than
the
borehole diameter BHD, the expansion element 30 can only expand until the
final outer
diameter OD3 matches the borehole diameter BHD. This can cause the expansion
element 30 to exert a pressure of between 300 and 500 psi on the borehole
wall.
[0019] The memory based packer can be adapted to selectively expand at
different
times; for example, where memory based foam is used, the foam material
composition
can be formulated to achieve the desired transition temperature. This quality
allows the
foam to be formulated in anticipation of the desired transition temperature to
be used for
a given application. For instance, in use with the present invention, the foam
material
composition can be formulated to have a transition temperature just slightly
below the
anticipated downhole temperature at the. depth at which the packer 10 will be
used. This
causes the expansion element 30 to expand at the temperature found at the
desired depth,
and to remain tightly sealed against the bore hole wall. Downhole temperature
can be
used to expand the expansion element 30; alternatively, other means can be
used, such as
a separate heat source. Such a heat source could be a wireline deployed
electric heater, or
a battery fed heater. For example, such a heat source could be mounted to the
mandrel
20, incorporated into the mandrel 20, or otherwise mounted in contact with the
foam
expansion element 30. The heater could be controlled from the surface of the
well site, or
it could be controlled by a timing device or a pressure sensor. Still further,
an exothermic
reaction could be created by chemicals pumped downhole from the surface, or
heat could
be generated by any other suitable means. Also, on a tool where several
packers 10 are
employed, each packer can be formulated to expand at a different temperature,
giving the
operator individual control of the expansion of each packer.
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[0020] As an alternative, if it is desired to enhance the overall amount of
packer
expansion achievable, in addition to the expansion achievable with a given
volume of
memory based material, the mandrel 20 itself can be a hollow base element
which can be
expanded radially. This additional expansion can be achieved by the use of a
mechanical,
hydraulic, or hydro-mechanical device. For example, as shown in Figure 4, a
hydro-
mechanical expander 40 can be run into the tubing on a work string, either
before, during,
or after the memory based expansion of the material. The hydro-mechanical
expander 40
can consist essentially of an anchoring device 42, a hydraulic ram 44, and a
conical pig
46. Once the conical pig 46 reaches the mandrel 20, the anchoring device 42 is
activated
to anchor itself to the tubing. Activation of the anchoring device 42 can be
mechanical,
electrical, or hydraulic, as is well known in the art. Once the expander 40 is
thusly
anchored in place, the hydraulic ram 44 can be pressurized to force the
conical pig 46 into
and through the mandrel 20 of the packer 10, as shown in Figure 5. Since the
outer
diameter of the conical pig 46 is selected to be slightly larger than the
inner diameter of
the mandrel 20, as the conical pig 46 advances through the mandrel 20, it
radially
expands the mandrel 20.
[0021] As mentioned above, this expansion of the mandrel 20 can be
implemented before, during, or after the memory based expansion of the
expansion
element 30. It can be seen that radial expansion of the mandrel 20 in this way
can
enhance the overall expansion possible with the packer 10. Therefore, for a
given amount
of memory based material in the expansion element 30, the final diameter to
which the
packer 10 can be expanded can be increased, or the pressure exerted by the
expanded
packer 10 can be increased, or both. For example, a relatively smaller overall
diameter
packer 10 can be run into the hole, thereby making the running easier, with
mandrel
expansion being employed to achieve the necessary overall expansion. Or, a
relatively
larger overall diameter packer 10 can be run into the hole, with mandrel
expansion being
employed to achieve a higher pressure seal against the borehole wall.
[0022] As a further alternative to use of the hydro-mechanical expander 40,
the
mandrel 20 can be expanded by mechanically forcing a conical pig 50 through
the
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mandrel 20 with a work string, as shown in Figures 6 and 7. Forcing of the pig
50
through the mandrel 20 can be either by pushing with the work string, as shown
in Figure
6, or by pulling with the work string, as shown in Figure 7. Still further,
the mandrel 20
can be expanded by hydraulically forcing a conical pig 60 through the mandrel
20 with
mud pump pressure, as shown in Figure 8.
[0023] While memory based packers are preferred, other barriers used downhole
to isolate one portion of the wellbore from another can be used as
alternatives. These
barriers can be mechanically or hydraulically set packers, inflatables, or
materials that can
be deposited in an annular space and become firm barriers such as, for
example, cement.
100241 The present invention provides one or more memory based packers 10
between two or more sections of radially telescoping perforating elements, for
selectively
perforating a well bore liner, fracturing a formation, and producing or
injecting fluids,
sand-free. Examples of such tools are shown in Figures 9 through 16. In each
of these,
the memory based packers 10 are mounted on a tubular tool body having a
plurality of
radially outwardly telescoping tubular elements. The radially telescoping
tubular
elements are grouped in two or more groups, separated vertically, to align
with the
various zones of the formation in which the tool will be used. Packers can be
provided
between the groups of telescoping tubular elements. A mechanical means can be
provided for selectively controlling the hydrostatic fracturing of the
formation through
one or more of the telescoping elements and for selectively controlling the
sand-free
injection or production of fluids through one or more of the telescoping
elements.
Selective expansion of the memory based packers 10 is as described above.
10025] The apparatus can have a built-in sand control medium in one or more of
the telescoping elements, to allow for injection or production, and a check
valve in one or
more of the telescoping elements, to allow for one way flow to hydrostatically
fracture the
formation without allowing sand intrusion after fracturing. Vertical isolation
of the zones
is achieved by placement of one or more memory based packers 10.
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[0026] Other types of telescoping perforation sections used in the apparatus
of the
present invention, along with the memory based packer, can have a sleeve which
shifts
between a fracturing position and an injection/production position, to convert
the tool
between these two types of operation. The sleeve can shift longitudinally or
it can rotate.
[0027] In a first shifting-sleeve type, the sleeve can be a solid walled
sleeve, as
shown in Figures 9 and 10, which shifts to selectively open and close the
different
telescoping elements, with some telescoping elements having a built-in sand
control
medium (which may be referred to in this case as "sand control elements") and
other
telescoping elements having no built-in sand control medium (which may be
referred to
in this case as "fracturing elements"). In this embodiment of the apparatus
100, the
shifting sleeve 16 is a solid walled sleeve as before, but it can be
positioned and adapted
to shift in front of, as in Figure 9, or away from, as in Figure 10, one or
more rows of
fracturing elements 12. It can be seen that the fracturing elements 12 have an
open
central bore for the passage of proppant laden fracturing fluid. The sand
control elements
14 can have any type of built-in sand control medium therein, with examples of
metallic
beads and screen material being shown in the Figures. Whether or not the
shifting sleeve
16 covers the sand control elements 14 when it uncovers the fracturing
elements 12 is
immaterial to the efficacy of the tool 100. Isolation between the zones is
provided by the
expanded memory based packer 10.
[0028] In a second shifting-sleeve type of the apparatus 100, as shown in
Figures
11 and 12, the sleeve itself can be a sand control medium, such as a screen,
which shifts
to selectively convert the telescoping elements between the fracturing mode
and the
injection/production mode. In this embodiment, none of the telescoping
elements would
have a built-in sand control medium. This longitudinally sliding shifting
sleeve 16 is
constructed principally of a sand control medium such as a screen. Figure 11
shows the
sleeve 16 positioned in front of the telescoping elements 12, for injection or
production of
fluid. Figure 12 shows the sleeve 16 positioned away from the telescoping
elements 12,
for pumping of proppant laden fluid into the formation. In this embodiment,
none of the
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telescoping elements has a built-in sand control medium. Isolation between the
zones is
provided by the expanded memory based packer 10.
[0029] In a third shifting-sleeve type, as shown in Figures 13 and 14, the
sleeve
can have ports which are shifted to selectively open and close the different
telescoping
elements, with some telescoping elements having a built-in sand control medium
(which
may be referred to in this case as "sand control elements") and other
telescoping elements
having no built-in sand control medium (which may be referred to in this case
as
"fracturing elements"). In this embodiment of the apparatus 100, the sleeve
shifts to
selectively place the ports over either the "sand control elements" or the
"fracturing
elements". This shifting sleeve 16 is a longitudinally shifting solid walled
sleeve having
a plurality of ports 24. The sleeve 16 shifts longitudinally to position the
ports 24 either
in front of or away from the fracturing elements 12. Figure 13 shows the ports
24 of the
sleeve 16 positioned away from the fracturing elements 12, for injection or
production of
fluid through the sand control elements 14. Figure 14 shows the ports 24 of
the sleeve 16
positioned in front of the fracturing elements 12, for pumping of proppant
laden fluid into
the formation. In this embodiment, the fracturing elements 12 have an open
central bore
for the passage of proppant laden fracturing fluid. The sand control elements
14 can have
any type of built-in sand control medium therein. Here again, whether or not
the shifting
sleeve 16 covers the sand control elements 14 when it uncovers the fracturing
elements
12 is immaterial to the efficacy of the tool 10. Isolation between the zones
is provided by
the expanded memory based packer 10.
[0030] In a fourth shifting-sleeve type, as shown in Figures 15 and 16, the
sleeve
can have ports, some of which contain a sand control medium (which may be
referred to
in this case as "sand control ports") and some of which do not (which may be
referred to
in this case as "fracturing ports"). In this embodiment of the apparatus 100,
none of the
telescoping elements would have a built-in sand control medium, and the sleeve
shifts to
selectively place either the "sand control ports" or the "fracturing ports"
over the
telescoping elements. This shifting sleeve 16 is a rotationally shifting solid
walled sleeve
having a plurality of ports 24, 26. A first plurality of the ports 26 (the
sand control ports)
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have a sand control medium incorporated therein, while a second plurality of
ports 24 (the
fracturing ports) have no sand control medium therein. The sleeve 16 shifts
rotationally
to position either the fracturing ports 24 or the sand control ports 26 in
front of the
telescoping elements 12. Figure 15 shows the fracturing ports 24 of the sleeve
16
positioned in front of the elements 12, for pumping of proppant laden fluid
into the
formation. Figure 16 shows the sand control ports 26 of the sleeve 16
positioned in front
of the telescoping elements 12, for injection or production of fluid through
the elements
12. In this embodiment, all of the telescoping elements 12 have an open
central bore;
none of the telescoping elements has a built-in sand control medium. Isolation
between
the zones is provided by the expanded memory based packer 10.
[0031] It should be understood that a rotationally shifting type of sleeve, as
shown
in Figures 15 and 16, could be used with only open ports, as shown in Figures
13 and 14,
with both fracturing elements 12 and sand control elements 14, without
departing from
the present invention. It should be further understood that a longitudinally
shifting type
of sleeve, as shown in Figures 13 and 14, could be used with both open ports
and sand
control ports, as shown in Figures 15 and 16, with only open'telescoping
elements 12,
without departing from the present invention.
[0032] While the particular invention as herein shown and disclosed in detail
is
fully capable of obtaining the objects and providing the advantages
hereinbefore stated, it
is to be understood that this disclosure is merely illustrative of the
presently preferred
embodiments of the invention and that no limitations are intended other than
as described
in the appended claims.
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