U.S. patent number 3,800,847 [Application Number 05/381,357] was granted by the patent office on 1974-04-02 for sand consolidation by adhesive agent and particulate pack.
Invention is credited to James L. Rike.
United States Patent |
3,800,847 |
Rike |
April 2, 1974 |
SAND CONSOLIDATION BY ADHESIVE AGENT AND PARTICULATE PACK
Abstract
The flow of sand into a well is controlled by injecting into the
producing zone a sand consolidation adhesive agent which will cause
consolidation of the sand particles by sticking one to another, and
forcing a particulate material into the producing zone after the
injection of the sand consolidation adhesive agent, and producing
through the consolidated sand and particulate material. A screen
may be placed in the particulate material or above the particulate
material to aid in mechanically supporting the particulate material
and holding the particulate pack in place. The method for
controlling the flow of sand into a well is especially suitable for
a cased well which has been perforated and provides an essentially
fail safe consolidation method.
Inventors: |
Rike; James L. (New Orleans,
LA) |
Family
ID: |
23504702 |
Appl.
No.: |
05/381,357 |
Filed: |
July 20, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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164751 |
Jul 21, 1971 |
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Current U.S.
Class: |
166/295; 166/276;
166/313 |
Current CPC
Class: |
E21B
43/025 (20130101); E21B 43/14 (20130101); E21B
43/04 (20130101) |
Current International
Class: |
E21B
43/00 (20060101); E21B 43/02 (20060101); E21B
43/04 (20060101); E21B 43/14 (20060101); E21b
033/138 (); E21b 043/04 (); E21b 043/08 () |
Field of
Search: |
;166/276,278,294,295,313,51 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Novosad; Stephen J.
Parent Case Text
This is a continuation of application Ser. No. 164,751, filed July
21, 1971, now abandoned.
Claims
The nature and object of the present invention having been
completely described and illustrated, and the best mode thereof
contemplated set forth, what I wish to claim as new and useful, and
secure by Letters Patent is:
1. A method for controlling the flow of sand into a well which
comprises:
injecting into a producing zone a sand consolidation adhesive agent
which will cause consolidation by the sand particles sticking one
to another,
forcing a particulate material substantially free of sand
consolidation adhesive agent into said producing zone after said
sand consolidation adhesive agent, and
producing through said consolidated sand and particulate
material.
2. A method according to claim 1 wherein said sand consolidation
adhesive agent is injected in two sequential steps.
3. A method according to claim 2 wherein one component of said sand
consolidation adhesive agent is injected in one step and a setting
agent component is injected thereafter.
4. A method according to claim 3 wherein said particulate material
is introduced into said producing zone with said setting agent
component.
5. A method according to claim 2 wherein said sand consolidation
adhesive agent is injected in one step and an after-flush stream is
injected thereafter.
6. A method according to claim 5 wherein said particulate material
is introduced into said producing zone in said after-flush
stream.
7. A method according to claim 1 wherein said particulate material
is forced into said producing zone at pressures equivalent to at
least 0.6 psi per foot of depth.
8. A method according to claim 1 wherein a screen is placed in
communication with a producing string after forcing said
particulate material into said producing zone and before commencing
producing.
9. A method according to claim 8 wherein said screen is within a
casing and said particulate material surrounds said screen and
extends into said producing zone.
10. A method according to claim 9 wherein said particulate material
is gravel.
11. A method according to claim 1 wherein said particulate material
is gravel.
12. A method according to claim 11 wherein said gravel is of
substantially uniform size ranging from about 3 to 12 mesh.
13. In a method for controlling the flow of sand into a well
wherein a sand consolidation adhesive agent has been introduced
into a producing zone to consolidate the sand, the improvement
which comprises:
forcing a particulate material substantially free of sand
consolidation adhesive agent into said producing zone after said
sand consolidation adhesive agent, and
maintaining said particulate material therein while producing
through said consolidated sand and particulate material.
14. In a method according to claim 13 wherein said particulate
material is forced into said producing zone at pressures equivalent
to at least 0.6 psi per foot of depth.
15. In a method according to claim 13 wherein said particulate
material is maintained in said producing zone by a screen.
16. In a method according to claim 15 wherein said screen is
concentric with said well.
17. In a method according to claim 15 wherein said screen is above
said particulate material and in communication with the producing
string.
18. A method according to claim 15 wherein said screen is within a
casing and said particulate material surrounds said screen and
extends into said producing zone.
19. A method according to claim 18 wherein said particulate
material is gravel.
20. A method according to claim 15 wherein said screen is within
one of a multiple of producing strings and said particulate
material contacts said screen and extends into said producing
zone.
21. A method according to claim 20 wherein said particulate
material is gravel.
22. In a method according to claim 13 wherein said sand
consolidation adhesive agent is a thermosetting resin.
23. In a method according to claim 22 wherein said particulate
material is gravel and is forced into said producing zone before
said thermosetting resin has hardened whereby said particulate
material provides a mechanical support while said thermosetting
resin hardens.
Description
BACKGROUND OF THE INVENTION
1 . Field of the Invention
The present invention is directed to a method for controlling the
flow of sand into a well. More particularly, the present invention
is directed to a method of sand consolidation wherein a sand
consolidation adhesive agent is injected into the producing zone of
the well and followed by a particulate material being forced into
the producing zone to form a particulate pack which is held
mechanically in place preferably by a screen in the particulate
material and in communication with the producing string.
2. Prior Art
U.S. Pat. No. 3,336,980
SUMMARY OF THE INVENTION
The flow of sand into a well is controlled by injecting into the
well and into a producing zone a sand consolidation adhesive agent
which will cause consolidation of the sand particles by sticking
the particles one to another, forcing a particulate material into
the producing zone after the injection of the sand consolidation
adhesive agent, and then producing through the consolidated sand
and the particulate material. The loose sand or unconsolidated sand
in a well or surrounding a casing in a well in a producing zone is
consolidated by a sand consolidation adhesive agent and then
mechanically held in place by the particulate material which forms
a particulate pack. It is preferred to force the particulate
material into the producing zone at high pressures after the sand
consolidation adhesive agent has already been injected into the
zone at low pressures so that high permeability fingers of
particulate material extend out into the consolidated zone and
possibly into the unconsolidated producing zone. A screen is placed
in the particulate material or above the particulate material to
aid in mechanically holding the particulate pack in place.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an idealized gravel pack;
FIG. 2 is a schematic view depicting the actual results of a gravel
pack;
FIG. 3 is a schematic view of an idealized plastic treatment for
sand consolidation;
FIG. 4 is a schematic view depicting the actual results of a
plastic treatment for sand consolidation;
FIG. 5 is a schematic view of an idealized resin-sand pack;
FIG. 6 is a schematic view depicting the actual results of a
resin-sand pack;
FIG. 7 is a schematic view of a perforating gun for perforating the
casing in a well;
FIG. 8 is a schematic view wherein a sand consolidation adhesive
agent is injected into a producing zone of perforated casing in a
typical well;
FIG. 9 is a schematic view of the forcing of a particulate material
into a producing zone according to the present invention;
FIG. 10 is a schematic view of a well consolidated according to the
present invention having a slotted screen in the casing;
FIG. 11 is a schematic view of a well consolidated according to the
present invention wherein the particulate material has been forced
into the producing zone at pressures high enough to cause fingers
of particulate material to extend through the consolidated zone;
and,
FIG. 12 is a schematic view of a multiple completion well employing
the sand consolidation method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be best illustrated by comparison to
some of the known industry methods for sand consolidation.
Referring to FIG. 1, an idealized gravel pack method for sand
consolidation is disclosed. A well casing 10 which may or may not
be cemented in place is positioned in producing zone 12. The well
casing 10 is perforated and has perforations 13, 14, 15, 16, 17,
and 18 as illustrated. A screen 19 is in communication with a
producing string and has a plurality of slits 20 in the screen 19.
Packed around the screen 19 is gravel 21. The gravel 21 is graded
in size and is of a size larger than the fine unconsolidated sand
in the production zone 12. A typical gravel 21 would be such that
thirty percent would pass through 40 mesh screen, 40 percent
through a 50 mesh screen, and about 30 percent through a 60 mesh
screen.
As depicted in FIG. 2, the actual results of most industry gravel
packs are in no way near that of the idealized gravel pack depicted
in FIG. 1. A casing 10 which has been cemented in place by cement
11 is in a producing zone 12. The cemented casing 10 is then
perforated with perforations 23, 24, 25, 26, 27, and 28. However,
in any perforation operation, certain of the perforations are
immediately plugged or become plugged. Perforations 24 and 26 are
shown plugged by debris 29. The debris 29 may be portions of the
casing 10 or the cement 11 or the perforating means whether it be a
shaped charge, bullet projectile, or the like. Furthermore, a
perforation may be plugged with solid particles from the fluid in
the well when perforating, especially if that fluid is the
filter-cake building mud used to drill the well; or a perforation
may be plugged with fine particles from the wash water or workover
water even used in the well after being perforated. These particles
are shown as fines 30 in perforation 23. Production is thus limited
to possibly one or several gravel packed fingers 31 extending into
the producing formation 12 and maintaining flow through one or more
perforations such as 25, 27 and 28. The producing channels 31,
however, are of limited productivity since they are only of
moderate permeability due to the nature of the gravel 21 used in a
gravel pack. The inherent nature of a successful gravel pack
requires graded sand fine enough to prevent the finer
unconsolidated sand from the producing zone 12 flowing into the
gravel pack and plugging the gravel pack. It must also keep sand
out of the well and producing string in communication with the
screen 19. The restricted productivity of the gravel-packed flow
channels is most pronounced at the perforation of the casing and
cement. In this portion of the perforation, there is usually a
restricted area of one-quarter square inch or less through a length
of about 2 inches, which is the length through the casing wall and
cement sheath.
Referring to FIG. 3 is an idealized plastic treatment for sand
consolidation. In a well 40 which may be cased and cemented (not
shown) as desired in communication with a producing zone 42 are
perforation fingers 43, 44, 45, 46, 47 and 48. The formation sand
in the producing zone 42 is consolidated with a resin 49 pumped
from the surface into the producing zone 42 through the
perforations 43 - 48, inclusive.
The actual results of an industry plastic treatment is depicted in
FIG. 4. The well 40 is in communication with a producing zone 42.
The well casing or tubing or multiple completion equipment (not
shown) in the well 40 is perforated at perforations 43, 44, 45, 46,
47, and 48 adjacent to the producing zone 42. The consolidation
resin 49 is introduced through the perforations. However, debris
usually plugs certain of the perforations, for example the debris
50 plugging the perforations 44 and 46. The extent to which the
resin 49 extends out into the producing zone 42 and consolidates
the loose sand will depend upon the permeability of the formation
42 adjacent each of the perforations as well as the condition of a
certain perforation as to whether that perforation is free for
resin 49 to flow through that certain perforation. The pressure
differentials may be such that the resin 49 penetrates only a very
short distance through a particular perforation and out into the
formation. This is depicted in a shallow and weakly consolidated
portion 51 through perforation 43. Upon attempting to produce from
zone 42, there are several points of failure which may immediately
fail. The debris 50 may flow into the well 40 or the weakly
consolidated portion 51 may break due to its shallow
penetration.
Still another approach to sand consolidation is depicted in FIG. 5
in the resin-sand pack. A casing 60 is cemented into place by
cement 61 in a producing zone 62. The well casing 60 is perforated
at the perforations 63, 64, 65, 66, 67, and 68. Introduced through
the perforations 63 - 68, inclusive, and out into the producing
zone 62 having fine, unconsolidated sand is a resin-coated large
sand 69 which has been prepared at the surface and pumped into
place.
However, the actual results of a resin-sand pack is depicted in
FIG. 6. Here, the casing 60 cemented into place by cement 61 in the
producing zone 62 has perforations 73, 74, 75, 76, 77, and 78,
respectively. Perforations 74 and 76, however, are plugged with
debris. Thus, when the resin coated sand 69 is pumped through the
casing 60, the resin coated sand 69 may not be able to enter the
producing formation 62 through perforations 74 or 76 at all. In
other perforation the resin coated sand 69 may only enter the
perforation, such as 73, and not enter the producing zone 62 at
all. As to other perforations, the resin coated sand 69 flows out
into the producing zone such as through the perforations 75, 77 and
78, respectively. Hence, the resin-sand pack has likely points of
failure immediately, or after a small amount of production, at
perforations 73, 74, or 76. Furthermore, during the injection
process, formation sand becomes consolidated with the plastic
leached out of the resin pack. Resin designed to consolidate large
pack sand leaves a very low permeability at the inflow face 79,
since this resin on fine formation sand leaves very little space
remaining for producing fluids to flow.
According to the present invention, referring to FIG. 7 of the
drawings, a well which may be cased by casing 110 and cemented into
place by cement 111 is perforated in a producing zone 112. The
perforations 113, 114, 115, 116, 117, and 118 are produced by a
perforating means 119 being placed in the well adjacent the
producing zone 112. As shown in FIG. 7, a varying amount of debris
remains in each of the perforations 113 - 118, in the newly
perforated tubing or casing 110. The debris in the perforations may
be removed in part by a washing step wherein by circulation and
reverse circulation sand and debris is washed out of the well.
Referring to FIG. 8, through a tubing 120 in the casing 110, a sand
consolidation adhesive agent 121 is injected into the producing
zone 112. The debris in some of the perforations and the
permeability of the producing zone 112 behind the perforations
makes the sand consolidation adhesive agent 121 flow out into the
producing zone 112 in a manner other than that which is ideal. The
sand consolidation adhesive agent 121 may be a thermoplastic resin
which is injected in two steps, one being the resin per se and the
other injecting stream being a catalyst or setting or curing agent
to aid in the polymerization of the thermoplastic resin or the
adhesive agent 121 may be injected so that the thermoplastic resin
and setting agent are injected together initially followed by an
after-flush stream for placement of the resin and/or to maintain
the permeability within the producing zone 112. While thermosetting
resins are preferred, any adhesive agent may be used which will
consolidate the sand particles by sticking one to another.
Phenol-formaldehyde and epoxy-type resins have been successfully
used. Specific resins and their specific steps for injection are
set forth in U.S. Pat. No. 3,336,980 and the patents referred to
therein.
After injecting the sand consolidation adhesive agent 121,
particulate material 122 is injected through the pipe 120, as shown
in FIG. 9, and forced into the producing zone 112 after the sand
consolidation adhesive agent 121 using pressures higher than those
used in injecting the adhesive agent 121. The particulate material
122 is preferably a large gravel having a smooth surface to produce
a high permeability mechanical support although other particulate
material having sufficient strength to withstand the pressures and
give mechanical support may be used. For example, a gravel wherein
one hundred percent passes through a six mesh screen but
essentially none will pass through a 12 mesh screen is preferred.
The gravel 122 after being forced into the producing zone 112 thus
mechanically supports the sand consolidation adhesive agent 121 and
maintains it in place as well as mechanically supporting points of
weakness where little or no adhesive agent has penetrated the
producing zone 112. The gravel 122 may be introduced after both
streams of the sand consolidation adhesive agent has been injected
into the producing zone 112, or more preferably, the gravel 122 is
injected into the second stream of the adhesive agent after an
initial portion has been introduced, thus being in the latter
portion of the catalyst or after-flush stream. Sufficient gravel
122 is introduced so that it extends about 20 to 60 feet above the
top perforation in the casing 110.
Referring to FIG. 10, after the gravel 122 has been forced into the
producing zone 112, a slotted screen 123 may be placed inside the
casing 110 having a plurality of slots 124. The screen 123 aids in
mechanically supporting the particulate material 122 and holding
the particulate pack in place. Thus, the sand consolidation method
of the present invention is fail-safe, in that a failure of the
consolidation adhesive agent 121 to penetrate the unconsolidated
sand does not produce points of failure. For example, in the
plugged perforations 114 and 117, the particulate material 122
mechanically supports the debris in the plugged perforations such
that it is unlikely that the debris will even be loosened during
production. Even if loosened, it will compact at the inner face
with the gravel 122 and plug the particulate material 122 in an
area around that perforation without interfering with other
perforations. Likewise, at a weakly consolidated perforation such
as perforation 118, the mechanical support of the particulate pack
will prevent failure due to the weak consolidation. Even if loose
sand from the producing zone 112 does come into contact with the
particulate material 122 the sand will plug that perforation
without interfering with other perforations. Furthermore, according
to the present invention, the sand consolidated by the sand
consolidation adhesive agent 121 need not have nearly the strength
necessary for sand control as when the adhesive agent 121 is used
alone without the particulate pack since the consolidated sand is
supported mechanically during production of the fluids in the
producing zone 112 by the particulate material 122 and the screen
123. The limited productivity of gravel pack systems is eliminated
by the use of coarse particulate matter, preferably gravel, for the
particulate pack. The large size gravel also permits clean up of
fines, mud particles and plugging material which would otherwise
plug a gravel pack system. The limited productivity caused by a
normal gravel pack being plugged with fine formation sand is
eliminated by consolidating the formation sand out beyond the
particulate pack interval with the sand consolidation adhesive
agent 121. Furthermore, the sand consolidation method of the
present invention leaves no opportunity for resin coated sand to
accumulate inside the well bore, either during treatment or during
the waiting time for the resin to set and consolidate the sand,
thus eliminating any necessity for a difficult or expensive clean
up job, or the potential complete loss of the well due to plugging
of the well bore with undrillable material.
As shown in FIG. 11, it is preferred that the particulate material
122 or gravel be forced into the producing zone 12 under high
pressures equivalent to 0.6 psi per foot of depth, or higher. The
forcing of the particulate material 122 or gravel at high pressures
produces a high permeability finger 125 extending out into the
producing zone 112 and which may extend past the sand consolidation
adhesive agent 121 in certain instances. The high permeability
finger 125, if it so extends beyond the adhesive agent 121 will
tend to plug with loose unconsolidated sand 126 at the outer tip
while still maintaining the high permeability within the finger 125
adjacent to the consolidated sand.
While the present invention has been illustrated in a cased well,
which has been described as duly perforated and consolidated in a
continuous operation, the present invention is not so limited in
that the injection of the particulate material may be carried out
in a well which has been previously consolidated with a sand
consolidation adhesive agent such as a thermoplastic resin and in
which the sand consolidation adhesive agent has already hardened.
Furthermore, the well treated according to the present invention
may have already been on production and the injection of the sand
consolidation adhesive agent and particulate material or the
injection of the particulate material to an already consolidated
formation may be done as a workover operation. Still further, the
injection of the particulate material into a producing zone which
has already had a sand consolidation adhesive agent injected
thereinto may be into a producing zone which is below the
casing.
Furthermore, rather than a simple cased well having only a single
production zone, the present invention may be carried out in a
multiple completion well, as illustrated in FIG. 12, having a
casing 140 extending to producing zones 141 and 142. String 143 is
in communication with the producing zone 142 whereas the string 144
is in communication with the producing zone 141. Suitable packers
145 and 146 separate the specific producing zone 141 wherein the
sand consolidation method of the present invention may be carried
out. After injection of the sand consolidation adhesive agent and
the forcing of the particulate material into the producing zone
141, a screen 147 may be placed in the string 144 above the
particulate material rather than being set in the particulate
material or gravel within the casing 140. While the screen 147 is
shown in the string 144 to illustrate another placement of the
screen, it may be preferred to have a concentric screen (as
illustrated in FIG. 10) extending down from the producing string
144 in a multiple completion well. In some instances a concentric
screen and a screen in the producing string may be used in the
particulate pack. Since a large size particulate material, such as
three or four mesh gravel, may be used in the process of the
present invention, productivity is reduced very little as a result
of the gravel being packed between the casing wall and the screen,
whether the screen is in the particulate pack or in the producing
string.
The preferred embodiments having been described, it is to be
understood that the present invention is not limited by the manner
in which the sand consolidation adhesive agent is injected into the
producing formation or to any specific procedure which may be used
in injecting the adhesive agent into the formation. Therefore, the
adhesive agent may be injected into the producing formation in the
manner used in a resin-sand pack consolidation process wherein a
particulate material is coated with the adhesive agent. Still
further, the present invention may be carried out in a well wherein
the steps of the present invention are preceded by the injection of
acid, surfactant, a mutual solvent, a fracture treatment, or any
combination of these. Furthermore, the present invention may be
used to repair ruptured or damaged casing where the damage exists
within the producing zone.
* * * * *