U.S. patent application number 13/653690 was filed with the patent office on 2014-07-24 for produced sand gravel pack process.
The applicant listed for this patent is Ronald van Petegem. Invention is credited to Ronald van Petegem.
Application Number | 20140202694 13/653690 |
Document ID | / |
Family ID | 49382327 |
Filed Date | 2014-07-24 |
United States Patent
Application |
20140202694 |
Kind Code |
A9 |
van Petegem; Ronald |
July 24, 2014 |
Produced Sand Gravel Pack Process
Abstract
A borehole completion method treats a formation surrounding a
borehole with a chemical treatment that alters how formation
particulates interact. A standalone screen deploys downhole in the
borehole (either before or after the treatment) on a downhole
string. When fluid is produced, formation particulates treated with
the chemical treatment agglomerate in the annulus surrounding the
screen in permeable structures. This can be especially when the
standalone screen is useful in a cased hole having perforations.
The chemical treatment includes an inner salt adapted to neutralize
the zeta potential (i.e., electrokinetic potential) of the
formation particulates so they aggregate into one or more permeable
structures in the annulus.
Inventors: |
van Petegem; Ronald;
(Montgomery, TX) |
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Applicant: |
Name |
City |
State |
Country |
Type |
van Petegem; Ronald |
Montgomery |
TX |
US |
|
|
Prior
Publication: |
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Document Identifier |
Publication Date |
|
US 20140102702 A1 |
April 17, 2014 |
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|
Family ID: |
49382327 |
Appl. No.: |
13/653690 |
Filed: |
October 17, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12690292 |
Jan 20, 2010 |
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13653690 |
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12151429 |
May 6, 2008 |
7956017 |
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12690292 |
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11298547 |
Dec 9, 2005 |
7392847 |
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12151429 |
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12075461 |
Mar 11, 2008 |
7829510 |
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12690292 |
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11298556 |
Dec 9, 2005 |
7350579 |
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12075461 |
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61146386 |
Jan 22, 2009 |
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Current U.S.
Class: |
166/276 |
Current CPC
Class: |
E21B 43/08 20130101;
E21B 43/04 20130101; E21B 43/25 20130101 |
Class at
Publication: |
166/276 |
International
Class: |
E21B 43/08 20060101
E21B043/08 |
Claims
1. A borehole completion method, comprising: treating a formation
surrounding a borehole with a chemical treatment; deploying a
screen in the borehole; allowing formation particulates to migrate
to an annulus surrounding the screen by initially producing fluid
from the formation; agglomerating the formation particulates
treated with the chemical treatment and produced with the fluid
from the formation; forming a gravel pack structure in the annulus
surrounding the screen with the agglomerated formation
particulates; and subsequently producing the fluid from the
formation through the formed gravel pack structure and the
screen.
2. The method of claim 1, wherein deploying the screen comprises
deploying the screen before treating the formation, after treating
the formation, during treatment of the formation, or a combination
thereof.
3. The method of claim 1, wherein treating the formation comprises
passing the chemical treatment through a perforation in a casing of
the borehole.
4. The method of claim 1, wherein treating the formation comprises
injecting the chemical treatment directly in the borehole.
5. The method of claim 1, wherein the chemical treatment comprises
a chemical additive adapted to modify a zeta potential of the
formation particulates.
6. The method of claim 5, wherein the chemical additive comprises
an inner salt adapted to modify the zeta potential of the formation
particulates.
7. The method of claim 1, wherein the screen comprises a wire
screen, a mesh screen, a sintered metal screen, a perforated pipe,
an expandable screen, a gravel pack screen, or a combination
thereof.
8. The method of claim 1, wherein agglomerating the particulates
comprises neutralizing a zeta potential of the formation
particulates with the chemical treatment and agglomerating the
neutralized zeta potential particulates into one or more permeable
structures in the annulus.
9. The method of claim 1, further comprising isolating a portion of
the formation with a packer disposed on a string having the
screen.
10. The method of claim 1, comprising performing the agglomeration
of the formation particulates instead of packing the annulus with
gravel.
11. The method of claim 1, wherein treating the formation
surrounding the borehole with the chemical treatment comprises:
injecting the chemical treatment in a fluid into the formation; and
diverting the injected fluid into the formation that follows the
fluid already migrating in the formation in response to an
increased viscosity of the migrating fluid caused by reduced
velocity and shear rate of the migrating fluid.
12. A method of completing a borehole for production, comprising:
treating portion of a formation surrounding a borehole with a
chemical treatment affecting a surface charge of formation
particulates; deploying a screen on a string downhole; allowing
formation particulates to migrate to an annulus surrounding the
screen by initially producing fluid from the formation; and
aggregating the formation particulates produced from the formation
into one or more permeable structures in the annulus surrounding
the screen by allowing the formation particulates with the affected
surface charge to attract to one another; and screening the
produced fluid using the screen and the one or more permeable
structures formed in the annulus.
13. The method of claim 12, wherein deploying the screen comprises
deploying the screen before treating the formation, after treating
the formation, during treatment of the formation, or a combination
thereof.
14. The method of claim 12, wherein treating the formation
comprises passing the chemical treatment through a perforation in a
casing of the borehole.
15. The method of claim 12, wherein treating the formation
comprises injecting the chemical treatment directly in the
borehole.
16. The method of claim 12, wherein the chemical treatment
comprises a chemical additive adapted to modify a zeta potential of
the formation particulates.
17. The method of claim 16, wherein the chemical additive comprises
an inner salt adapted to modify the zeta potential of the formation
particulates.
18. The method of claim 12, wherein the screen comprises a wire
screen, a mesh screen, a sintered metal screen, a perforated pipe,
an expandable screen, a gravel pack screen, or a combination
thereof.
19. The method of claim 12, wherein agglomerating the particulates
comprises neutralizing a zeta potential of the formation
particulates with the chemical treatment and agglomerating the
neutralized zeta potential particulates into t'-one or more
permeable structures in the annulus.
20. The method of claim 12, further comprising isolating a portion
of the formation with a packer disposed on a string having the
screen.
21. The method of claim 12, comprising performing the agglomeration
of the formation particulates instead of packing the annulus with
gravel.
22. The method of claim 12, wherein treating the portion of the
formation surrounding the borehole with the chemical treatment
affecting the surface charge of the formation particulates
comprises: injecting the chemical treatment in a fluid into the
formation; and diverting the injected fluid into the formation that
follows the fluid already migrating in the formation in response to
an increased viscosity of the migrating fluid caused by reduced
velocity and shear rate of the migrating fluid.
Description
BACKGROUND
[0001] Several types of screens are used downhole to filter
produced fluids of formation particulates, such as sand. The
screens can include wire-wrapped screens, metal-mesh screens, and
expandable screens, among others. The screens can be used downhole
in a number of completion systems to control sand. In a gravel pack
operation, for example, gravel is placed in the annulus around the
screen in an open hole. Alternatively, the screen can be run in a
stand-alone application without a surrounding gravel pack in either
a cased or an open hole.
[0002] A stand-alone screen can become plugged and/or may erode
rapidly as formation sand and other produced particulates pass
through the screen during production. When plugging or erosion
occurs, operators need to take remedial steps to clean out and/or
replace the screen, which can be time-consuming and costly.
Plugging and erosion can be especially problematic when the
stand-alone screen is run in a cased hole. For this reason, a
stand-alone screen is only rarely run in a cased hole. Yet, being
able to run a stand-alone screen in a cased hole may be beneficial
in some circumstances and may also be beneficial when using screens
in open hole applications.
[0003] The subject matter of the present disclosure is directed to
overcoming, or at least reducing the effects of, one or more of the
problems set forth above.
SUMMARY
[0004] A borehole completion method treats a formation surrounding
a borehole with a chemical treatment. A standalone screen deploys
downhole in the borehole (either before, during, or after the
treatment) on a downhole string. Any suitable type of standalone
screen can be used, including a wire screen, a mesh screen, a
sintered metal screen, a perforated pipe, an expandable screen, a
gravel pack screen, or a combination thereof. Typically, packers
disposed on the string are used to isolate the screen to particular
portions of the borehole.
[0005] When fluid is produced from the formation through the
screen, formation particulates treated with the chemical treatment
are produced with the fluid from the formation, and they
agglomerate in the annulus surrounding the screen in permeable
structures to form a type of "gravel pack" structure. With the
permeable structures formed in the annulus, operators do not need
to actively pack the annulus with gravel.
[0006] The chemical treatment to agglomerate formation particulates
can be especially useful in a cased hole having perforations, but
the process may also be beneficial for open hole applications. A
standalone screen in a cased hole can be prone to clogging and
erosion. Thus, the chemical treatment can be passed through
perforations in the casing to treat the surrounding formation. This
can be accomplished by injecting the chemical treatment directly in
the borehole through the screen, by capillary string, or other
conveyance.
[0007] The chemical treatment includes an inner salt adapted to
modify the zeta potential of the formation particulates. As
discussed herein, zeta potential of a particulate refers to the
electrokinetic potential of the particulates and is represented by
a charge of the particulates' surfaces. To agglomerate the
particulates, the chemical treatment neutralizes the zeta potential
of the formation particulates so they aggregate into one or more
permeable structures in the annulus.
[0008] The foregoing summary is not intended to summarize each
potential embodiment or every aspect of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a borehole of a formation having a
completion string with multiple stand-alone screens.
[0010] FIG. 2 illustrates one technique for injecting chemical
treatment into the formation.
[0011] FIG. 3 illustrates agglomerating of formation particulates
treated with the chemical treatment and produced with the fluid
from the formation in an annulus surrounding the screen.
[0012] FIG. 4 illustrates a process for chemically treating a
formation so plugging and erosion can be reduced for stand-alone
screens deployed downhole.
[0013] FIG. 5 shows the change of zeta potential in silica and
ground coal samples when treated with a Zeta Potential Altering
System.
DETAILED DESCRIPTION
[0014] In FIG. 1, a completion string 20 has a number of
stand-alone screens 30 deployed in a cased hole 10. Packers 22
disposed at various intervals between zones of interest isolate the
annulus 14 between the casing 12 and the string 20, and the cased
hole 10 has perforations 16 communicating with the surrounding
formation of these zones. As fluid is produced from the formation,
the produced fluid can pass through the perforations 16 into the
borehole annulus 14. In turn, the produced fluid can enter the
screens 30 and be produced up the string 20 at various wellhead
components 26. As shown, a mechanical barrier 24 can be disposed
downhole of the string 20 to isolate the bottom of the cased hole
10.
[0015] The screens 30 used can include any of the conventional
screens used for gravel pack operations, frac pack operations, or
wellscreen operations. Therefore, the screens 30 can use wrapped
wire, sintered metal, mesh, perforated pipe, ceramic screens, and
other components.
[0016] During production (60), fluid is produced from the formation
through the casing's perforations 16. As this process proceeds,
formation sand and other particulates may tend to plug and/or erode
the screens 30, and this may be accelerated by virtue of the
perforations 16 in the cased hole 10. To reduce the chances of
plugging and erosion, the completion has a chemical treatment (50)
applied to surrounding portions or areas 40 of the formation
according to the procedures disclosed herein. (FIG. 2, which is
discussed below, shows one technique for treating areas 40 of the
formation with the chemical treatment (50).) These treated areas 40
can extend into the surrounding formation as shown. The actual
extent of these treated areas 40 may vary depending on how much
chemical treatment is applied, characteristics of the formation,
and other factors.
[0017] In any event, as shown in FIGS. 1 and 3, produced fluid 60
exits the treated formation area 40 through the perforations 16,
sand and other particulates produced with the fluid will tend to
collect in the annulus 14 surrounding the screen 30 and the casing
12. Left alone, these formation particulates would tend to plug and
erode the screens 30. Being chemically treated, however, the
collected formation particulate is intended to have a significant
amount of permeability that tends to reduce plugging and erosion.
Moreover, the chemically treated formation particulate agglomerates
together in the annulus 14 to form one or more permeable structures
42 for filtering produced fluids and reducing plugging and erosion
of the screens 30. In other words, these permeable structures 42
can act as a gravel pack formed from the produced sand and
particulate in the annulus 14 around the screen 30 without the
structures 42 being formally placed there through gravel packing
operations.
[0018] Although the chemical treatment (50) is applied to the cased
hole 10 in which the stand-alone screens 30 are used, the teachings
of the present disclosure can be used in open holes in which
stand-alone screens are used. Moreover, the borehole 10 may have a
combination of cased and open hole sections as found in the
art.
[0019] Still referring to the components in FIGS. 1 and 3,
discussion now turns to the flowchart in FIG. 4, which shows a
process 100 for chemically treating the surrounding formation to
reduce plugging and erosion for stand-alone screens 30. Initially,
the completion string 20 is deployed in the borehole 10 and has a
number of packers 22 and stand-alone screens 30 on the production
tubing (Block 102). The packers 22 can then be activated to isolate
the zones of interest in the formation from one another according
to customary procedures (Block 104).
[0020] A chemical treatment (50) is then applied downhole so that
it permeates into the surrounding formation (Block 106). As noted
above, the borehole 10 through the formation may have a cased hole
with perforations 16 or may be an open hole. In general, the
treatment (50) can be applied before, during, and/or after the
screens 30 and completion string 20 have been deployed.
Accordingly, the procedure for treating the formation can use any
of the available methods depending on what tools can be deployed,
how the chemical treatment (50) can be conveyed downhole, and other
factors known in the art. Thus, standard chemical injection
procedures can be used to apply the chemical treatment (50). Some
of these standard chemical injection procedures can involve pumping
the treatment (50) directly down the completion string 20, applying
the treatment (50) with a capillary or workstring deployed in the
completion string 20, or other techniques.
[0021] When the chemical treatment (50) is applied after the
completion string 20 is run, for example, the chemical additive of
the treatment (50) can be pumped down the tubing string 20 so that
it exits the screens 30 and enters the formation through the cased
hole perforations 16. This chemical additive can even be part of a
frac operation used to stimulate the formation.
[0022] As one example placement technique shown in FIG. 2, chemical
injection uses a "self-diverting" fluid for the chemical treatment
50. This fluid is designed to be very thin and easy to inject into
the formation. A capillary or workstring string 28 deployed in the
completion string 20 injects the thin fluid for the chemical
treatment 50 downhole, and the injected fluid passes out of the
screen 30 and through the perforations 16. Entering the formation
through the perforations 16, the injected fluid migrates into the
surrounding area 40 of the formation. As the thin fluid migrates,
the velocity and shear rate of the fluid is reduced, causing the
fluid to become more viscous. In turn, the increasing viscosity of
the migrating fluid causes the following fluids being injected
behind it to be diverted to other parts of the formation in a
self-diverting process.
[0023] Returning back to FIG. 4, the chemical treatment (50) treats
the formation substrate (sand, particulates, etc.) with the
chemical additive that allows the formation particulates, if free,
to flow or otherwise move towards the screens 30. Yet, as fluids
are produced and enter the screens 30 (Block 108), the migrating
formation particulates collect in the annulus 14 around the screens
30. However, the previously applied chemical additive prevents the
formation particulates from substantially plugging the screens 30
or otherwise preventing the well from flowing by causing the
formation particulates to agglomerate and form stable and permeable
structures (e.g., 42 in FIG. 3) around the screens 30 (Block
110).
[0024] One suitable chemical additive that can be used for this
purpose includes a Zeta Potential Altering System (hereafter called
ZPAS). This type of chemical additive alters the Zeta potential of
the downhole formation substrate so that formation particulates are
attracted to each other. Zeta potential refers to the
electrokinetic potential of the particulates and is represented by
a charge of the particulates' surfaces.
[0025] The Zeta Potential Altering System (ZPAS) used for the
chemical treatment (50) of the present disclosure can be a chemical
additive based on an inner salt that modifies the zeta potential of
the particulates. In particular, the system changes the
particulates' charge towards neutral values, which enhances the
agglomeration of the particulates.
[0026] Further details of the chemical additive for the Zeta
Potential Altering System can be found in D. Johnson, et al.,
"Enhancing Gas and Oil Production With Zeta Potential Altering
System," SPE 128048 (2010), which is discussed below. Other
possible chemical additives could be used that alter the
electrokinetic potential of the particulates.
[0027] As specifically discussed in SPE 128048, a Zeta Potential
Altering System (ZPAS) can be used in hydraulic fracturing
treatments. The system minimizes proppant flow back, controls fines
migration, enhances fluid load recovery, and inhibits calcium
carbonate scale formation. The Zeta Potential Altering System is
based on an inner salt and modifies the zeta potential of particles
such as fracture sand and formation substrate, changing the charge
towards neutral values and therefore enhancing particle
agglomeration. As also discussed in SPE 128048, formations can be
treated by incorporating the chemical additive into stimulation
fluids, and the chemical additive can be applied using several
fluid systems to deliver the product.
[0028] As discussed in SPE 128048, Zeta Potential is defined by the
charge that develops at the interface in the boundary of
hydrodynamic shear between solid surfaces as a product of the
electrostatic repulsion and the attractive forces related to the
Van der Waals' forces. Therefore, zeta potential is a function of
the surface charge of the particle, any adsorbed layer at the
interface, and the nature and composition or the surrounding
suspension medium. In other words, zeta potential can be affected
by changes in pH, conductivity of the medium (salinity and kind of
salt), and concentration of particular additives (polymer,
non-ionic surfactants, etc.). Particles with zeta potential values
between -20 and 20 mV have an effective charge low enough that the
repulsion between them is lowered to a point where aggregation
occurs.
[0029] As discussed in SPE 128048, the active ingredient of the
Zeta Potential Altering System is an inner salt of a very
low-molecular weight polymer. When added to fracture water as
discussed in SPE 128048, the inner salt disperses and rapidly coats
any metal oxide substrate, such as proppant or subterranean
formation. The system also contains a penetrating alcohol capable
of disrupting the water layer that coats solid surfaces in the
formation. The system does not modify the chemical structure of
friction reducers and gelling systems, such as non-ionic, cationic,
and anionic polyacrylamide and guar gums and derivatives so the
system is compatible with slick-water systems and borate-based
crosslinked gels.
[0030] SPE 128048 provides a Figrure, reproduced here as FIG. 5,
showing the change in the zeta potential in 325 mesh silica and in
ground coal samples when treated at concentrations of 6 gal of ZPAS
per 1,000 lb of silica or of coal material. In both cases, the ZPAS
increases the mean zeta potential of the particles towards more
neutral values with a lower standard deviation. The resulting
values are in the zeta potential range where higher agglomerating
effects are expected.
[0031] The particular aspects of the chemical additive applied in
the chemical treatment 50 may depend on the expected chemistry
downhole, including considerations of temperature, pressure, type
of produce fluid, expected size of formation particulates, expected
types of formation substrate, etc. Being able to treat the
formation so that formation particulates form permeable, stable
structures around the stand-alone screens 30 can eliminate the need
to actively pack the annulus with gravel in a gravel pack
operation. Moreover, the disclosed techniques can allow expandable
sand screens (ESS) to be run in a cased hole, which can have
advantages in some implementations. Use of the chemical treatment
can also allow stand-alone screens 30 that have larger outside and
inside dimensions to be installed downhole.
[0032] Treating the formation with chemical additive according to
the present disclosure can preferably be done before or at the time
of first production. Depending on the implementation, additional
additive may be needed to continue to create or maintain the
permeable structure in the annulus.
[0033] The foregoing description of preferred and other embodiments
is not intended to limit or restrict the scope or applicability of
the inventive concepts conceived of by the Applicants. In exchange
for disclosing the inventive concepts contained herein, the
Applicants desire all patent rights afforded by the appended
claims. Therefore, it is intended that the appended claims include
all modifications and alterations to the full extent that they come
within the scope of the following claims or the equivalents
thereof.
* * * * *