WELL SCREENS HAVING ENHANCED WELL TREATMENT
CAPABILITIES
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 a well screen assembly with enhanced well treatment
capabilities.
BACKGROUND
Various compositions can be used to treat a well in
order to remove or dissolve a mud cake on the wall of a
wellbore, to increase permeability in the near-wellbore
region of a formation intersected by the wellbore, etc. It
will be appreciated that improved results could be obtained
if enhanced methods of delivering the compositions into more
intimate contact with the wellbore wall could be developed.
Therefore, it will also be appreciated that
improvements are needed in the art of well treatment.SUMMARY
In the disclosure below, systems and methods are
provided which bring improvements to the art of well
treatment. One example is described below in which a well
treatment substance is displaced closer to a wellbore wall
by expansion of a well screen assembly. Another example is
described below in which a well treatment stimulant is used
to disperse the well treatment substance.
In one aspect, the present disclosure provides to the
art a well screen assembly. The well screen assembly can
include a well treatment substance secured to the well
screen assembly, and at least one reactive component of a
well treatment stimulant. The reactive component can also
be secured to the well screen assembly.
In another aspect, the disclosure provides a method of
treating a well. The method can include expanding a well
screen assembly outward in a wellbore of the well, thereby
decreasing a distance between a well treatment substance and
a wall of the wellbore.
In yet another aspect, a method of treating a well is
provided, with the method comprising the step of contacting
multiple reactive components of a well treatment stimulant
with each other in the well, thereby dispersing a well
treatment substance about a well screen assembly.
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 representative partially cross-sectional
view of a well system and associated method which can embody
principles of the present disclosure.
FIGS. 2A & B are enlarged scale representative cross-
sectional views through a well screen assembly, taken along
line 2-2 of FIG. 1 .
FIG. 3 is a further enlarged scale representative
cross-sectional view of one side of the well screen
assembly, taken along line 3-3 of FIG. 2A.
FIGS. 4A & B are further enlarged scale representative
views of a coating on the well screen assembly.
FIGS. 5-9 are representative cross-sectional views of
additional configurations of the well screen assembly.
DETAILED DESCRIPTION
Representatively illustrated in FIG. 1 is a well system
10 and associated method which can embody principles of this
disclosure. In the well system 10, a well screen assembly
12 is installed in a wellbore 14. The screen assembly 12 is
interconnected as part of a tubular string 16 for production
of fluids to the surface from a formation 18 surrounding the
wellbore 14.
Although a production operation is depicted in FIG. 1
for the well system 10, it should be understood that the
principles of this disclosure are also applicable to
injection or other types of well operations. Although the
wellbore 14 is depicted in FIG. 1 as being uncased or "open
hole," it should be understood that the screen assembly 12
could be installed in a cased or lined wellbore in otherexamples. It is also not necessary for the tubular string
16 to be configured as shown in FIG. 1 , or for the screen
assembly 12 to be interconnected in a tubular string at all.
Therefore, it should be clearly understood that the
principles of this disclosure are not limited to any details
of the well system 10 illustrated in FIG. 1 or described
herein. Instead, a large variety of possible well system
configurations and methods can incorporate the principles of
this disclosure, and the well system 10 of FIG. 1 is merely
one example, which is used for the purpose of illustrating
those principles.
In one important feature of the screen assembly 12 of
FIG. 1 , a well treatment substance is incorporated into the
screen assembly, so that the well treatment substance is
conveyed into the wellbore 14 with the screen assembly. In
various examples, the well treatment substance could be
incorporated into a base pipe, an outer shroud, a filter
portion, an annular area between these or other components,
other areas in the screen assembly 12, etc.
Suitable well treatment substances for use in the well
system 10 include those described in U.S. Patent Nos.
7360593, 6831044 and 6394185, and in U.K. Publication No.
GB2365043, the entire disclosures of which are incorporated
herein by this reference. Other types of well treatment
substances may be used, if desired. Preferably, the well
treatment substance is effective to dissolve a mud cake on a
wall 20 of the wellbore 14 and in the near-wellbore region
of the formation 18, and preferably the well treatment
substance is effective to increase a permeability of the
formation, at least in the near-wellbore region.
In one example, the screen assembly 12 is expanded
radially outward in the wellbore 14, thereby also displacingthe well treatment substance closer to the wellbore wall 20
(and, thus, closer to any mud cake on the wellbore wall).
This can be advantageous for promoting contact between the
well treatment substance and the wall 20 of the wellbore 14,
or at least decreasing the distance between the well
treatment substance and the wellbore wall to enhance
effectiveness of the treatment.
In another example, at least one reactive component of
a well treatment stimulant is also carried with the screen
assembly 12 into the wellbore 14. The one or more reactive
components could, for example, be included with the well
treatment substance in a coating applied to the interior,
exterior and/or in the sidewall of the screen assembly 12.
In this manner, the well treatment stimulant is in close
proximity to the well treatment substance for effective
stimulation of the well treatment.
The well treatment stimulant can enhance the well
treatment reaction in various ways. For example, when
reactive components of the stimulant are placed in contact
with each other, gas and/or heat may be produced. The gas
can promote dispersing of the well treatment substance, so
that it more readily and completely reacts with the mud cake
surrounding the screen assembly 12. The heat can increase
the rate of the reaction(s) by which the well treatment
substance dissolves the mud cake, increases the near-
wellbore permeability of the formation 18, etc.
One suitable well treatment stimulant results from a
reaction between NaN0 2 (sodium nitrite) and NH C1 (ammonium
chloride). The products of this reaction include heat and
nitrogen gas. Another suitable well treatment stimulant is
marketed by Halliburton Energy Services, Inc. of Houston,
Texas USA as SURETHERM (TM ) for cleaning pipelines.If multiple components of the well treatment stimulant
are included in a coating, then the components can contact
and react with each other when a matrix material of the
coating is dissolved. The coating matrix material can be
dissolved by any means, including but not limited to,
contact with water, acid, etc., pH adjustment, heat, passage
of time, or any other means.
If a fluid (or a slurry of carrier fluid and solids
entrained in the carrier fluid) is circulated to the screen
assembly 12 to dissolve the coating matrix material, one of
the reactive components of the well treatment stimulant can
be included with the fluid. In this way, the reactive
components (in the coating, and in the circulated fluid) can
come into contact with each other and react concurrently
with the well treatment substance being released from the
coating .
Referring additionally now to FIGS. 2A & B , enlarged
scale cross-sectional views of the screen assembly 12 in the
wellbore 14 are representatively illustrated. This example
of the screen assembly 12 includes an inner base pipe 22, a
filter portion 24 and an outer shroud 26.
The screen assembly 12 filters fluid 28 which flows
from the formation 18 into an inner passage 30 of the screen
assembly for production to the surface via the tubular
string 16. In injection operations, the fluid 28 would flow
in the opposite direction.
As described more fully below, the well treatment
substance and/or one or more reactive components of the well
treatment stimulant may be incorporated into or otherwise
secured to the screen assembly 12, so that they are
installed together in the wellbore 14. The well treatment
substance and/or reactive component (s) of the well treatmentstimulant may, for example, be applied to interior and/or
exterior surfaces of the base pipe 22, filter portion 24
and/or outer shroud 26, disposed between or within any of
these elements of the screen assembly, etc. Thus, any
location of the well treatment substance and/or reactive
component (s) of the well treatment stimulant relative to the
elements of the screen assembly 12 may be used in keeping
with the principles of this disclosure.
The filter portion 24 is schematically depicted in
FIGS. 2A & B as a single element, but it should be
understood that any number of filter portions may be used,
and a single filter portion may comprise any number of
individual components or layers, if desired. The filter
portion 24 may comprise wire mesh, sintered, wire wrapped,
pre-packed, or any other type of filtering elements, and any
number or combination of filtering elements.
Note that the base pipe 22, filter portion 24 and outer
shroud 26 are depicted in FIGS. 2A & B as merely one example
of elements which can be included in a screen assembly.
This combination of elements is not necessary in a screen
assembly which embodies principles of this disclosure. For
example, it is not necessary for the screen assembly 12 to
include the outer shroud 26, etc.
In the configuration of FIG. 2A, an annulus 32 is
formed radially between the screen assembly 12 and the
wellbore wall 20. However, in FIG. 2B, screen assembly 12
has been radially outwardly expanded, so that the annulus 32
is eliminated, or at least substantially reduced.
Expansion of the screen assembly 12 brings the well
treatment substance into much closer proximity to, and
possibly into direct contact with, the wall 20 of the
wellbore 14. If one or more reactive components of the welltreatment stimulant are also included in the screen assembly
12, then the component (s) may also be brought into closer
proximity to the wellbore wall 20 by expansion of the screen
assembly.
Note that it is not necessary in keeping with the
principles of this disclosure for the screen assembly 12 to
be expanded. Instead, those principles could also be
practiced, even if the screen assembly 12 remains in its
configuration as depicted in FIG. 2A.
Referring additionally now to FIG. 3 , an enlarged scale
longitudinal cross-section of one side of the screen
assembly 12 is representatively illustrated. In this view,
it may be seen that a coating 34 is applied to inner and
outer surfaces of the base pipe 22, filter portion 24 and
outer shroud, and fills any annular spaces between these
elements .
One advantage to using the coating 34 is that it can
prevent plugging of the filter portion 24 during
installation and expansion of the screen assembly 12 in the
wellbore 14, but a matrix material 36 of the coating can
then be readily dissolved when or after the screen assembly
is installed and expanded. Dissolving of the matrix
material 36 can release the well treatment substance and/or
release one or more reactive components of the well
treatment stimulant. The dissolving step may be performed
before, during and/or after expanding the well screen
assembly 12.
Referring additionally now to FIGS. 4A & B , enlarged
scale schematic views of the coating 34 are representatively
illustrated. In FIG. 4A, the coating comprises at least the
well treatment substance 38 in the matrix material 36.At least one reactive component 40 of the well
treatment stimulant may also be incorporated into the
coating 34, if desired. When the matrix material 36 is
dissolved, the well treatment substance 38 and the reactive
component 40 of the well treatment stimulant are released.
Preferably, another reactive component 42 of the well
treatment stimulant would be included in the fluid
circulated to the screen assembly 12 to dissolve the matrix
material 36. For example, NaN0 2 (sodium nitrite) could be
included in the coating 34, and NH C 1 (ammonium chloride)
could be circulated with the fluid when the matrix material
36 is to be dissolved.
In the configuration of FIG. 4B, both reactive
components 40, 42 of the well treatment stimulant are
included in the coating 34, along with the well treatment
substance 38. In this way, when the matrix material 36 is
dissolved, the reactive components 40, 42 can contact each
other when they are released from the matrix material, along
with the well treatment substance 38.
Referring additionally now to FIG. 5 , another
configuration of the expandable well screen assembly 12 is
representatively illustrated. In this example, separate
longitudinally extending filter portions 24 are extended
radially outward in a well when an annular swellable
material 44 on the base pipe 22 swells in response to
contact with a particular fluid (which may or may not be the
same fluid as the fluid 28). Such expandable well screens
may be known as "swell expandable screens."
The coating 34 can fill any void spaces in the filter
portions 24, and/or between the filter portions, can coat
the outside of the filter portions, etc. The well treatmentsubstance 3 8 , reactive component 4 0 and/or reactive
component 4 2 can be included in the coating 3 4 .
Referring additionally now to FIG. 6 , another
configuration of the expandable well screen assembly 12 is
representatively illustrated. In this example, the filter
portion 2 4 comprises a shape memory polymer foam expanding
porous media, of the type marketed by Baker Hughes, Inc.
The filter portion 2 4 expands radially outward in response
to elevated downhole temperature.
The coating 3 4 (comprising the well treatment substance
3 8 , reactive component 4 0 and/or reactive component 4 2 ) can
fill any void spaces in the porous foam filter portion 2 4 ,
outside of the filter portion and/or in a drainage layer 4 6
disposed radially between the base pipe 2 2 and the filter
portion 2 4 . The coating 3 4 can coat the exterior and/or
interior of the well screen assembly 12 .
Referring additionally now to FIG. 7 , another
configuration of the well screen assembly 12 is
representatively illustrated. In this configuration,
inflation tubes 4 8 are positioned radially between the
filter layer 2 4 and the base pipe 2 2 . When the tubes 4 8 are
inflated, the filter portion 2 4 is extended outward.
The coating 3 4 (comprising the well treatment substance
3 8 , reactive component 4 0 and/or reactive component 4 2 ) can
fill any void spaces in the filter portion 2 4 , outside of
the filter portion and/or about the inflation tubes 4 8
between the base pipe 2 2 and the filter portion 2 4 . The
coating 3 4 can coat the exterior and/or interior of the well
screen assembly 12 .
Referring additionally now to FIG. 8 , another
configuration of the well screen assembly 12 is
representatively illustrated. The well screen assembly 12depicted in FIG. 8 is similar in many respects to a well
screen marketed as the ESS(TM) by Weatherford International,
Inc. of Houston, Texas USA, although some proportions (such
as gaps between the outer shroud 26, filter portion 24 and
base pipe 22, etc.) have been exaggerated for illustrative
clarity .
In this configuration, the base pipe 22 comprises a
slotted or perforated expandable liner, and the outer shroud
26 is slotted for ease of expansion. The filter portion 24
may comprise a mesh filter material.
The coating 34 can fill any void spaces in the filter
portion 24, gaps between the filter portion and the base
pipe 22 and/or outer shroud 26. The coating can coat the
exterior and/or interior of the well screen assembly 12.
Referring additionally now to FIG. 9 , another
configuration of the well screen assembly 12 is
representatively illustrated. The well screen assembly 12
depicted in FIG. 9 is similar in many respects to a well
screen marketed as the EXPress(TM) by Baker Oil Tools, Inc.
of Houston, Texas USA, although some proportions (such as
gaps between the outer shroud 26, filter portion 24 and base
pipe 22, etc.) have been exaggerated for illustrative
clarity .
In this configuration, the base pipe 22 comprises a
slotted or perforated expandable liner, and the outer shroud
26 is slotted for ease of expansion. The filter portion 24
may comprise multiple overlapping leaves made of a mesh
filter material.
The coating 34 can fill any void spaces in the filter
portion 24, gaps between the filter portion and the base
pipe 22 and/or outer shroud 26. The coating can coat the
exterior and/or interior of the well screen assembly 12.It may now be fully appreciated that the present
disclosure provides several advancements to the art of well
treatment. The well treatment stimulant can promote more
effective treatment by the well treatment substance, whether
or not the screen assembly is expanded. If used in an
expandable screen assembly, the well treatment substance can
more effectively treat the well, even if the well treatment
stimulant is not provided.
The above disclosure provides to the art an improved
well screen assembly 12. The screen assembly 12 can include
a well treatment substance 38 secured to the well screen
assembly 12, and at least one reactive component 40 of a
well treatment stimulant, with the reactive component 40
also being secured to the well screen assembly 12.
The well treatment substance 38 and the reactive
component 40 can be incorporated into a coating 34 applied
to the well screen assembly 12. A matrix material 36 of the
coating 34 may isolate multiple reactive components 40, 42
of the well treatment stimulant from each other.
The matrix material 36 of the coating 34 may be
dissolvable. The coating 34 can prevent plugging of a
filter portion 24 of the well screen assembly 12 during
installation and expansion of the well screen assembly 12 in
a well.
The well treatment stimulant may generate gas and/or
heat when multiple reactive components 40, 42 of the well
treatment stimulant react with each other.
The well treatment stimulant can comprise multiple
reactive components 40, 42, with the reactive components
comprising NaN02 and NH C1.The well treatment substance 38 may comprise a
permeability increaser and/or a mud cake dissolver.
The well screen assembly 12 may be expandable radially
outward in a well. The well treatment substance may be
secured to an outwardly extendable portion of the well
screen assembly 12.
Also described by the above disclosure is a method of
treating a well. The method can include expanding a well
screen assembly 12 outward in a wellbore 14 of the well,
thereby decreasing a distance between a well treatment
substance 38 and a wall 20 of the wellbore 14. This
distance decreasing can include bringing the well treatment
substance into direct contact with the wall of the wellbore.
The method can include incorporating the well treatment
substance 38 into the well screen assembly 12.
The method can include incorporating at least one
reactive component 40 of a well treatment stimulant into the
well screen assembly 12.
The method can include dissolving a matrix material 36
of the coating 34 in the well. The dissolving step may be
performed before, during and/or after expanding the well
screen assembly 12.
The coating 34 preferably prevents plugging of a filter
portion 24 of the well screen assembly 12 during
installation and expansion of the well screen assembly 12 in
the well.
The above disclosure also describes a method of
treating a well, with the method including the step of
contacting multiple reactive components 40, 42 of a well
treatment stimulant with each other in the well, therebydispersing a well treatment substance 38 about a well screen
assembly 12.
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 well screen assembly, comprising:
a well treatment substance secured to the well screen
assembly; and
at least one reactive component of a well treatment
stimulant, the at least one reactive component being secured
to the well screen assembly.
2 . The well screen assembly of claim 1 , wherein the
well treatment substance and the reactive component are
incorporated into a coating applied to the well screen
assembly.
3 . The well screen assembly of claim 2 , wherein a
matrix material of the coating isolates multiple reactive
components of the well treatment stimulant from each other.
4 . The well screen assembly of claim 2 , wherein a
matrix material of the coating is dissolvable.
5 . The well screen assembly of claim 2 , wherein the
coating prevents plugging of a filter portion of the well
screen assembly during installation of the well screen
assembly in a well.
6 . The well screen assembly of claim 2 , wherein the
coating prevents plugging of a filter portion of the wellscreen assembly during expansion of the well screen assembly
in a well.
7 . The well screen assembly of claim 1 , wherein the
well treatment stimulant generates gas when multiple
reactive components of the well treatment stimulant react
with each other.
8 . The well screen assembly of claim 1 , wherein the
well treatment stimulant generates heat when multiple
reactive components of the well treatment stimulant react
with each other.
9 . The well screen assembly of claim 1 , wherein the
well treatment stimulant comprises multiple reactive
components, the reactive components comprising NaN02 and
NH C1.
10. The well screen assembly of claim 1 , wherein the
well treatment substance comprises a permeability increaser.
11. The well screen assembly of claim 1 , wherein the
well treatment substance comprises a mud cake dissolver.
12. The well screen assembly of claim 1 , wherein the
well screen assembly is expandable radially outward in a
well .13. The well screen assembly of claim 1 , wherein the
well treatment substance is secured to an outwardly
extendable portion of the well screen assembly.
14. A method of treating a well, the method comprising
the step of:
expanding a well screen assembly outward in a wellbore
of the well, thereby decreasing a distance between a well
treatment substance and a wall of the wellbore.
15. The method of claim 14, further comprising the
step of incorporating the well treatment substance into the
well screen assembly.
16. The method of claim 15, wherein the incorporating
step comprises incorporating at least one reactive component
of a well treatment stimulant into the well screen assembly.
17. The method of claim 16, wherein the well treatment
stimulant generates gas when multiple reactive components of
the well treatment stimulant react with each other.
18. The method of claim 16, wherein the well treatment
stimulant generates heat when multiple reactive components
of the well treatment stimulant react with each other.
19. The method of claim 16, wherein the well treatment
stimulant comprises multiple reactive components, the
reactive components comprising NaN02 and NH C1.20. The method of claim 15, wherein the incorporating
step comprises incorporating the well treatment substance
into a coating applied to the well screen assembly.
21. The method of claim 20, wherein a matrix material
of the coating isolates multiple reactive components of a
well treatment stimulant from each other.
22. The method of claim 20, further comprising the
step of dissolving a matrix material of the coating in the
well .
23. The method of claim 22, wherein the dissolving
step is performed after the expanding step.
24. The method of claim 22, wherein the dissolving
step is performed during the expanding step.
25. The method of claim 22, wherein the dissolving
step is performed before the expanding step.
26. The method of claim 20, wherein the coating
prevents plugging of a filter portion of the well screen
assembly during installation of the well screen assembly in
the well.
27. The method of claim 20, wherein the coating
prevents plugging of a filter portion of the well screenassembly during expansion of the well screen assembly in the
well .
28. The method of claim 14, wherein the well treatment
substance comprises a permeability increaser.
29. The method of claim 14, wherein the well treatment
substance comprises a mud cake dissolver.
30. The method of claim 14, wherein the well treatment
substance is secured to an outwardly extendable portion of
the well screen assembly.
31. A method of treating a well, the method comprising
the step of:
contacting multiple reactive components of a well
treatment stimulant with each other in the well, thereby
dispersing a well treatment substance about a well screen
assembly.
32. The method of claim 31, further comprising the
step of incorporating the well treatment substance into the
well screen assembly.
33. The method of claim 31, further comprising the
step of incorporating at least one reactive component of the
well treatment stimulant into the well screen assembly.34. The method of claim 33, wherein the incorporating
step comprises incorporating the at least one reactive
component and the well treatment substance into a coating
applied to the well screen assembly.
35. The method of claim 34, wherein a matrix material
of the coating isolates the multiple reactive components of
a well treatment stimulant from each other.
36. The method of claim 34, further comprising the
step of dissolving a matrix material of the coating in the
well .
37. The method of claim 34, wherein the coating
prevents plugging of a filter portion of the well screen
assembly during installation of the well screen assembly in
the well.
38. The method of claim 34, wherein the coating
prevents plugging of a filter portion of the well screen
assembly during expansion of the well screen assembly in the
well .
39. The method of claim 31, wherein the well treatment
stimulant generates gas when the multiple reactive
components of the well treatment stimulant react with each
other .
40. The method of claim 31, wherein the well treatment
stimulant generates heat when the multiple reactivecomponents of the well treatment stimulant react with each
other .
41. The method of claim 31, wherein the reactive
components comprise NaN02 and NH C1.
42. The method of claim 31, wherein the well treatment
substance comprises a permeability increaser.
43. The method of claim 31, wherein the well treatment
substance comprises a mud cake dissolver.
44. The method of claim 31, further comprising the
step of expanding the well screen assembly outward in a
wellbore of the well, thereby decreasing a distance between
the well treatment substance and a wall of the wellbore.
45. The method of claim 31, wherein at least one of
the reactive components is secured to an outwardly
extendable portion of the well screen assembly.