VARYING PORE SIZE IN A WELL SCREEN
TECHNICAL FIELD
This disclosure relates generally to equipment utilized
and operations performed in conjunction with a subterranean
well and, in an example described below, more particularly
provides for varying pore size in a well screen.
BACKGROUND
It can be beneficial to perform certain operations with
well screens. Therefore, improvements in operations with
well screen are needed in the art.
SUMMARY
In the disclosure below, a well system, method and well
screen are provided which bring improvements to the art of
well operations utilizing well screens. One example is
described below in which flow resistance through a well
screen can be varied. Another example is described below in
which a substance can be selectively released from a well
screen.
In one aspect, this disclosure provides to the art a
method which can include applying a magnetic field to a well
screen, thereby varying sizes of pores via which fluid flows
through the well screen.
In another aspect, this disclosure provides to the art
a well screen which can include a magnetic shape memory
material having a dimension which changes in response to
application of a magnetic field. Restriction to flow
through the well screen can vary in response to the change
in dimension of the magnetic shape memory material.
These and other features, advantages and benefits will
become apparent to one of ordinary skill in the art upon
careful consideration of the detailed description of
representative examples below and the accompanying drawings,
in which similar elements are indicated in the various
figures using the same reference numbers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic partially cross-sectional view of
a well system and associated method which can embody
principles of the present disclosure.
FIG. 2 is a representative enlarged scale partially cut
away elevational view of a well screen which may be used in
the well system and method of FIG. 1 .
FIG. 3 is a further enlarged scale representative
cross-sectional view of the well screen.
FIG. 4 is another representative cross-sectional view
of the well screen.
FIG. 5 is a representative cross-sectional view of the
well screen with a magnetic tool therein.
FIGS. 6 & 7 are further enlarged scale cross-sectional
views of a magnetic shape memory material.
FIG. 8 is a representative flowchart for the method.
FIGS. 9 & 10 are representative flowcharts for
variations of the method.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is an example of
a well system 10 and associated method which can embody
principles of this disclosure. In the well system 10, a
generally vertical section 12 of a wellbore 14 has casing 16
lining an upper portion thereof, and a generally horizontal
section 18 of the wellbore 14 penetrates an earth formation
20.
A tubular string 22 (such as a production tubing
string, coiled tubing, jointed or continuous tubing, etc.)
is installed in the wellbore 14. A series of well screens
24 and packers 26 are interconnected alternately along the
tubular string 22 in the section 18 of the wellbore 14.
The packers 26 seal off an annulus 28 formed radially
between the tubular string 22 and the wellbore 14. In this
manner, fluid 30 is constrained to flow between the tubular
string 22 and specific divided-off zones or intervals of the
formation 20.
The fluid 30 could be injected into the formation 20 in
some circumstances (such as, in steam flood, water flood,
gas drive, geothermal, stimulation, fracturing, conformance,
etc., operations). The fluid 30 could be received from the
formation 20 in other circumstances (such as, in hydrocarbon
production, geothermal, etc., operations). In still other
circumstances, the fluid 30 may be alternately injected and
received from the formation 20 (such as, in cyclic steam
injection or "huff and puff" operations, etc.).
Production of fluid 30 from the formation 20 can be
regulated at each of the individual zones or intervals, in
order to balance production, prevent water coning 32 or gas
coning 34. For example, flow of the fluid 30 through the
well screens 24 can be variably restricted by varying the
size of pores in a magnetic shape memory material of each of
the well screens 24.
In other examples, the magnetic shape memory material
may be used to selectively release a substance into the
wellbore 14, or into a flow of the fluid 30, etc. The
substance can be retained in the pores of the magnetic shape
memory material until it is released by, for example,
opening the pores, dissolving or otherwise dispersing the
substance, etc.
The substance can be used for preventing flow through
the pores, for treating the well (e.g., dissolving mud cake,
modifying flow characteristics of the formation 20, etc.),
for treating the fluid 30 (e.g., to prevent precipitates
from forming in the fluid, for reducing corrosion, for
preventing production of harmful fluids (e.g., a biocide for
preventing production of hydrogen sulfide, etc.) to the
surface, for identifying the interval or zone from which
fluid is produced (e.g., the substance could comprise a
marker, such as a dye or radioactive material, etc.), etc.
Any type of substance may be used with the well screens 24
in keeping with the principles of this disclosure.
In one feature of the well system 10, a magnetic field
can be conveniently applied to any of the well screens 24 in
the well, thereby changing a pore size of the magnetic shape
memory material. The change in pore size can be used to
vary a resistance to flow through the well screen 24, to
release a substance previously retained in the pores, to
permit flow through the well screen, to prevent flow through
the well screen, etc.
It should be clearly understood, however, that the well
system 10 and associated method is described herein as
merely one example of a wide variety of well systems and
methods which can benefit from the principles of this
disclosure. Therefore, the principles of this disclosure
are not limited at all to the details of the well system 10
are any other examples described herein or depicted in the
drawings .
Referring additionally now to FIG. 2 , an enlarged scale
partially cut away elevational view of one of the well
screens 24 is representatively illustrated. In this view,
it may be clearly seen that this example includes a
generally tubular base pipe 36 with openings 38 through its
sidewall to permit fluid 30 to flow between the annulus 28
and an interior flow passage 40 (not visible in FIG. 2 , see
FIG. 3 ) of the base pipe and tubular string 22.
The well screen 24 also includes a generally tubular
sleeve 42 comprising a magnetic shape memory material 44.
The material 44 overlies the openings 38, so that fluid 30
which flows through the well screen 24 (e.g., between the
flow passage 40 and the annulus 28) also flows through pores
of the material.
A filter or other outer shroud 46 outwardly overlies
the sleeve 42. As depicted in the figures, the shroud 46
comprises a wire wrapped filter, but a perforated outer
sleeve or other type of shroud may be used, if desired. In
other examples, the outer shroud 46 may not be used.
The material 44 is positioned between the base pipe 36
and the outer shroud 46 as illustrated in FIG. 2 . However,
in other examples the material 44 could be otherwise
positioned (e.g., within a base pipe, in a sidewall of the
base pipe, overlying a filter or other structure, etc.).
Thus, it should be clearly understood that the principles of
this disclosure are not limited to the specific examples of
well screen configurations depicted in the drawings and
described herein.
In FIG. 3 , an enlarged scale cross-sectional view of
the well screen 24 is representatively illustrated. In this
view, the manner in which the fluid 30 can flow inwardly
and/or outwardly through the well screen can be clearly
seen.
Note that the fluid 30 flows through the material 44
when it flows between the annulus 28 and the flow passage
40. In examples described below, the fluid 30 flows through
pores of the material 44. Sizes of the pores can be changed
by applying a magnetic field to the material 44. However,
in other examples, the fluid 30 may not flow through pores
of the material.
Referring additionally now to FIG. 4 , the well screen
24 is representatively illustrated after a magnetic field
has been applied to the well screen. The structure of the
material 44 has changed in response to the application of
the magnetic field.
The change in the structure of the material 44 can be
used to vary a resistance to flow of the fluid 30 through
the well screen 24, to release a substance from the
material, to treat the wellbore 14, to treat the formation
20, to treat the fluid 30, to open or close the well screen
to flow through the well screen, or for other purposes.
Referring additionally now to FIG. 5 , a magnetic tool
48 is representatively illustrated in the flow passage 40 of
the well screen 24. The tool 48 is used to apply one or
more magnetic fields Ml, M2 to the well screen 24 to thereby
change the structure of the material 44.
A magnetic shape memory material changes shape when a
magnetic field is applied to the material. More
specifically, a shape of the material changes when the
material is exposed to a magnetic field. The material will
retain the changed shape when the magnetic field is removed.
However, if another magnetic field oriented orthogonal to
the first magnetic field is exposed to the material, the
material will revert to its original shape.
A suitable material for use as the material 44 in the
well screen 24 is a magnetic shape memory foam made of a
nickel-manganese-gallium alloy. This type of metal magnetic
shape memory foam is described in an article published by
the National Science Foundation in 2009 entitled, "Metallic
Shape-Memory Foam Shows Giant Response to Magnetic Fields."
Another magnetic shape memory foam is described by Mullner,
Peter, et al., "Recent Developments in Ni-Mn-Ga Foam
Research," Materials Science Forum, vol. 635, pp. 119-124
(Trans Tech Publications, Switzerland, 2010). However, it
should be clearly understood that other types of magnetic
shape memory materials may be used in keeping with the
principles of this disclosure.
It is not necessary for the material 44 to be a metal
alloy, or for the material to be a foam. Magnetic particles
could be embedded in plastic or another material. Any type
of composite material with a magnetic or magnetizable
component, ceramics, etc., may be used, as long as the
material possesses (or can be "trained" or otherwise altered
to possess) magnetic shape memory characteristics.
The magnetic tool 48 can be used to apply either of the
orthogonal magnetic fields Ml, M2 at any time. For example,
the magnetic fields Ml, M2 , or either of them, could be
applied before and/or after the well screen 24 is installed
in the wellbore 14.
The magnetic tool 48 could be part of the well screen
24 (e.g., a slidable sleeve which can be selectively shifted
to thereby apply the magnetic fields to the material 44,
etc.). Alternatively, the tool 48 could be separately
conveyed into the well screen 24, for example, by wireline,
slickline, electric line, coiled tubing, etc. The tool 48
could be dropped and/or flowed through the passage 40.
The tool 48 could have any shape which is suitable for
displacement to or through the well screen 24. The tool 48
could comprise a bar, dart, sleeve, or any other type of
structure .
The magnetic fields Ml, M2 could be generated by
permanent magnets, electromagnets, or by any other source of
magnetic energy. The magnetic fields Ml, M2 could be
applied by switching on an electromagnet, deforming a
magnetostrictive material, positioning a magnet in close
proximity to the material 44, or by any other method.
The strength of the applied magnetic field can be
varied to thereby vary the amount of change in the material
44. The direction of the applied magnetic field can also be
varied to vary the amount of change in the material 44.
Referring additionally now to FIG. 6 , an enlarged scale
cross-sectional view of the material 44 is representatively
illustrated. In this view, it may be seen that the material
44 includes pores 50 therein.
Each pore 50 has a size s , such as a height, width,
flow area, etc. It is not necessary for all of the pores 50
to have the same size s .
In FIG. 6 , the material 44 is depicted in a
configuration in which the pore sizes s are relatively
small. However, in FIG. 7 , the pore sizes s are increased,
due to application of a magnetic field to the material 44.
The increased pore size s in the FIG. 7 configuration
can reduce the restriction to flow of the fluid 30 through
the pores 50. For a given pressure differential across the
well screen 24, the material 44 configuration of FIG. 7 will
allow for a greater rate of flow of the fluid 30
therethrough, as compared to the configuration of FIG. 6 .
In the FIG. 6 configuration, a substance 52 is retained
in the pores 50. The substance 52 is depicted as being in
solid form in FIG. 6 , but it could instead comprise a gel,
foam, coating, fluid, liquid, etc., in keeping with the
principles of this disclosure.
When the pore sizes s are increased as depicted in the
FIG. 7 configuration, the substance 52 is released, thereby
permitting increased flow of the fluid 30 through the pores
50. The substance 52 could entirely prevent flow of the
fluid 30 through the pores in the FIG. 6 configuration, and
release of the substance can then permit flow of the fluid
through the pores. In other examples, the substance 52
could be released from the pores, even though the fluid 30
does not flow through the pores.
The substance 52 could comprise a well treatment
substance, for example, which acts to dissolve a mud cake
lining the wellbore 14, or which alters flow characteristics
of the formation 20 (e.g., by increasing a permeability of
the formation, etc.).
The substance 52 could comprise a treatment for the
fluid 30, for example, to reduce precipitation in the fluid,
to reduce emulsif ication, or to reduce production of harmful
fluids (e.g., hydrogen sulfide, etc.).
The substance 52 could block flow through the well
screen 24 as it is being installed, while still permitting
flow of fluid through the passage 40, thereby preventing
plugging of the well screen. After the well screen 24 is
installed, the substance 52 can be released to allow flow of
the fluid 30 through the well screen.
The substance 52 may be released in a variety of ways.
Increasing the sizes s of the pores 50 can allow the
substance 52 to physically pass through the pores. The
substance 52 could be dissolved or otherwise dispersed more
readily when the sizes s of the pores 50 increase. The
fluid 30 itself could cause the substance 52 to dissolve or
disperse.
Note that it is not necessary for the substance 52 to
be present in the pores 50 when the sizes s of the pores are
reduced. Such reduction of the pores sizes s could be used
to increasingly restrict flow through the well screen 24
without the presence of the substance 52 in the material 44.
Referring additionally now to FIG. 8 , an example of a
method 54 which may be performed with the well system 10 is
representatively illustrated in flowchart form. Of course,
the method 54 can be performed with other well systems, in
keeping with the principles of this disclosure.
In step 56 of the method 54, the well screen 24 is
installed in the wellbore 14. At the time of installation,
the pore sizes s may be in their increased or reduced
configurations. A magnetic field may be applied to the well
screen 24 prior to installation, in order to achieve a
desired size s of the pores 50.
In step 58, a magnetic field is applied to the well
screen 24. The magnetic field may be applied using the tool
48 described above, or any other means of applying a
magnetic field may be used.
In step 60, the pore sizes s change in response to the
application of the magnetic field. The change may be an
increase in the pore sizes s , for example, to reduce a flow
restriction through the well screen 24, to entirely prevent
flow through the well screen, to release the substance 52
from the pores 50, etc.
Referring additionally now to FIG. 9 , another version
of the method 54 is representatively illustrated in
flowchart form. In this version, the substance 52 is placed
in the pores 50 while they are enlarged, prior to
installation of the well screen 24 in the wellbore 14.
In step 62, the pores 50 are open or relatively
enlarged, so that the substance 52 can be placed therein. A
magnetic field may be applied to the material 44, if needed,
to increase the sizes s of the pores 50.
In step 64, the substance 52 (such as a well or fluid
treatment, pore blocking substance, etc.) is placed in the
pores 50. The substance 52 can be placed in the pores 50 by
any means, such as, flowing the substance into the pores and
then allowing the substance to set therein, positioning a
solid substance in the pores, etc.
In step 6 6 , a magnetic field is applied to the material
4 4 . This reduces the pore sizes s .
In step 6 8 , the substance 5 2 is retained in the pores
5 0 , due to the reduced sizes s of the pores.
In step 7 0 , the well screen is installed in the well.
In step 7 2 , a magnetic field is applied to the material
4 4 . This increases the sizes s of the pores 5 0 , thereby
allowing the substance 5 2 to be released from the pores.
However, this step is optional since, as described above,
the substance 5 2 could be released from the pores 5 0 (e.g.,
by dissolving, etc.), without increasing the sizes s of the
pores .
Yet another version of the method 5 4 is
representatively illustrated in FIG. 1 0 in flowchart form.
In this version, the pore sizes s are alternately increased
and decreased as fluid 3 0 is alternately injected into, and
produced from, the formation 2 0 in a cyclic steam injection
operation .
In step 7 4 , the well screen 2 4 is installed in the
well. The pores 5 0 may be enlarged or reduced at this time.
In step 7 6 , steam is injected into the formation 2 0 via
the enlarged pores 5 0 . If not already enlarged, the pores
5 0 are preferably enlarged prior to flowing the steam
through the well screen 2 4 .
In step 7 8 , a magnetic field is applied to the well
screen 2 4 . This reduces the pores sizes s , and preferably
prevents or at least minimizes flow being received from the
formation 2 0 into the tubular string 2 2 as the steam
transfers thermal energy to the formation.
In step 8 0 , fluid 3 0 is produced from the formation 2 0
via the pores 5 0 , which are reduced as needed to filter the
fluid, to variably restrict flow of the fluid through the
well screen, etc.
In step 8 2 , a magnetic field is applied to the well
screen 2 4 , thereby increasing the pores sizes s in
preparation for another cycle of steam injection. Steps 76-
8 2 are repeated to alternately inject steam into the
formation 2 0 and produce fluid from the formation.
The various versions of the method 5 4 described above
demonstrate that the principles of this disclosure are not
limited to the specifics of only one or a few particular
examples. Instead, the principles of this disclosure are
applicable to a wide variety of different methods.
In certain examples, this disclosure provides to the
art a method 5 4 which can include applying a magnetic field
to a well screen 2 4 , thereby varying sizes s of pores 5 0 via
which fluid 3 0 flows through the well screen 2 4 .
The pores 5 0 may be formed in a magnetic shape memory
material 4 4 of the well screen 2 4 .
The magnetic field may be applied to the well screen 2 4
in a well.
The magnetic field may be applied to the well screen 2 4
prior to installation of the well screen 2 4 in a well.
A substance 5 2 may be released from the pores 5 0 in
response to applying the magnetic field.
The substance 5 2 may comprise a well treatment.
The substance 5 2 may block flow through the pores 5 0
prior to being released.
The substance 5 2 may be released by being dissolved.
The substance 5 2 may be released by being dispersed.
Applying the magnetic field to the well screen 24 may
increase and/or decrease the sizes of the pores 50, after
the well screen 24 is installed in a wellbore 14.
Applying the magnetic field to the well screen 24 may
comprise alternately increasing and decreasing the sizes s
of the pores 50.
The fluid 30 may flow in one direction through the well
screen 24 when the sizes s of the pores 50 are increased,
and the fluid 30 may flow in an opposite direction through
the well screen 24 when the sizes s of the pores 50 are
decreased.
Applying the magnetic field may close the pores 50,
thereby preventing flow of the fluid 30 through the pores
50.
Applying the magnetic field may open the pores 50,
thereby permitting flow of the fluid 30 through the pores
50.
Applying the magnetic field may comprise orienting the
magnetic field M l orthogonal to another magnetic field M2
previously applied to the well screen 24.
Applying the magnetic field may comprise orienting the
magnetic field M l in a direction different from another
magnetic field M2 previously applied to the well screen 24.
The different direction is not necessarily orthogonal to the
direction of the previously applied magnetic field M2 .
Applying the magnetic field may comprise variably
restricting flow of the fluid 30 through the well screen 24.
Also described by the above disclosure is a well screen
24. The well screen 24 can comprise a magnetic shape memory
material 44 having a dimension which changes in response to
application of a magnetic field. Restriction to flow
through the well screen 24 can vary in response to the
change in dimension of the magnetic shape memory material
44. The dimension is not necessarily an outer dimension or
total size of the shape memory material 44, but could
instead be, e.g., sizes s of the pores 50.
Fluid 30 which flows through the well screen 24 may
also flow through pores 50 of the magnetic shape memory
material 44.
The well screen 24 may include a substance 52 in the
pores 50. The substance 52 may comprise a well treatment.
The substance 52 may block flow through the pores 50. The
substance 52 may be dissolvable and/or dispersible in a
well .
The dimension may be a pore size s of the magnetic
shape memory material 44. Application of the magnetic field
to the well screen 24 may increase and/or decrease the pore
size s . Application of the magnetic field to the well
screen 24 may alternately increase and decrease the pore
size s .
It is to be understood that the various examples
described above may be utilized in various orientations,
such as inclined, inverted, horizontal, vertical, etc., and
in various configurations, without departing from the
principles of the present disclosure. The embodiments
illustrated in the drawings are depicted and described
merely as examples of useful applications of the principles
of the disclosure, which are not limited to any specific
details of these embodiments.
Of course, a person skilled in the art would, upon a
careful consideration of the above description of
representative embodiments, readily appreciate that many
modifications, additions, substitutions, deletions, and
other changes may be made to these specific embodiments, and
such changes are within the scope of the principles of the
present disclosure. Accordingly, the foregoing detailed
description is to be clearly understood as being given by
way of illustration and example only, the spirit and scope
of the present invention being limited solely by the
appended claims and their equivalents.
WHAT IS CLAIMED IS:
1 . A method, comprising:
applying a magnetic field to a well screen, thereby
varying sizes of pores via which fluid flows through the
well screen.
2 . The method of claim 1 , wherein the pores are
formed in a magnetic shape memory material of the well
screen.
3 . The method of claim 1 , wherein the magnetic field
is applied to the well screen in a well.
4 . The method of claim 1 , wherein the magnetic field
is applied to the well screen prior to installation of the
well screen in a well.
5 . The method of claim 1 , wherein a substance is
released from the pores in response to applying the magnetic
field.
6 . The method of claim 5 , wherein the substance
comprises a well treatment.
7 . The method of claim 5 , wherein the substance
blocks flow through the pores prior to being released.
8 . The method of claim 5 , wherein the substance is
released by being dissolved.
9 . The method of claim 5 , wherein the substance is
released by being dispersed.
10. The method of claim 1 , wherein applying the
magnetic field to the well screen increases the sizes of the
pores, after the well screen is installed in a wellbore.
11. The method of claim 1 , wherein applying the
magnetic field to the well screen decreases the sizes of the
pores, after the well screen is installed in a wellbore.
12. The method of claim 1 , wherein applying the
magnetic field to the well screen comprises alternately
increasing and decreasing the sizes of the pores.
13. The method of claim 12, wherein the fluid flows in
one direction through the well screen when the sizes of the
pores are increased, and the fluid flows in an opposite
direction through the well screen when the sizes of the
pores are decreased.
14. The method of claim 1 , wherein applying the
magnetic field closes the pores, thereby preventing flow of
the fluid through the pores.
15. The method of claim 1 , wherein applying the
magnetic field opens the pores, thereby permitting flow of
the fluid through the pores.
16. The method of claim 1 , wherein applying the
magnetic field comprises orienting the magnetic field
orthogonal to another magnetic field previously applied to
the well screen.
17. The method of claim 1 , wherein applying the
magnetic field comprises orienting the magnetic field
orthogonal to another magnetic field previously applied to
the well screen.
18. The method of claim 1 , wherein applying the
magnetic field comprises variably restricting flow of the
fluid through the well screen.
19. A well screen, comprising:
a magnetic shape memory material having a dimension
which changes in response to application of a magnetic
field, and
wherein restriction to flow through the well screen
varies in response to the change in dimension of the
magnetic shape memory material.
20. The well screen of claim 19, wherein fluid which
flows through the well screen flows through pores of the
magnetic shape memory material.
21. The well screen of claim 20, further comprising a
substance in the pores.
22. The well screen of claim 21, wherein the substance
comprises a well treatment.
23. The well screen of claim 21, wherein the substance
blocks flow through the pores.
24. The well screen of claim 21, wherein the substance
is dissolvable in a well.
25. The well screen of claim 21, wherein the substance
is dispersible in a well.
26. The well screen o f claim 19, wherein the dimension
is a pore size o f the magnetic shape memory material, and
wherein application o f the magnetic field to the well screen
increases the pore size.
27. The well screen o f claim 19, wherein the size is a
pore size o f the magnetic shape memory material, and wherein
application o f the magnetic field to the well screen
decreases the pore size.
28. The well screen o f claim 19, wherein the size is a
pore size o f the magnetic shape memory material, and wherein
application o f the magnetic field to the well screen
alternately increases and decreases the pore size.