U.S. patent application number 10/257374 was filed with the patent office on 2003-04-24 for packer, setting tool for a packer and method for setting a packer.
Invention is credited to Gunnarsson, Bengt.
Application Number | 20030075342 10/257374 |
Document ID | / |
Family ID | 19911054 |
Filed Date | 2003-04-24 |
United States Patent
Application |
20030075342 |
Kind Code |
A1 |
Gunnarsson, Bengt |
April 24, 2003 |
Packer, setting tool for a packer and method for setting a
packer
Abstract
The invention relates to a packer (7) to be included in a
production tubing (4) in a well bore (1). The packer (7) comprises
an expandable bag (11) located on the outside (56) of a packer body
(9), the bag (11) having an outwardly facing semi-permeable wall
(12) made from fabric. When setting the packer, a liquid curable
resin is injected into the bag (11), which causes an expansion of
the bag (11). The resin partly penetrates the outwardly facing
fabric wall (12) and seals against the well bore wall (10), and
after curing forms a packer seal (58). The invention also relates
to a setting tool for setting the packer (7) in the well bore (1)
and a method for setting a packer (7) in a well bore (1).
Inventors: |
Gunnarsson, Bengt; (Hundvag,
NO) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W.
SUITE 600
WASHINGTON
DC
20004
US
|
Family ID: |
19911054 |
Appl. No.: |
10/257374 |
Filed: |
October 17, 2002 |
PCT Filed: |
April 26, 2001 |
PCT NO: |
PCT/NO01/00175 |
Current U.S.
Class: |
166/387 ;
166/187 |
Current CPC
Class: |
E21B 33/134 20130101;
E21B 33/1277 20130101; E21B 23/06 20130101; E21B 33/1275
20130101 |
Class at
Publication: |
166/387 ;
166/187 |
International
Class: |
E21B 033/12 |
Claims
1. A packer (7) to be included in a production tubing (4) in a well
bore (1), for sealing against a wall (10) of the well bore (1),
wherein the packer (7) comprises an essentially cylindrical packer
body (9) with connections for connecting to the production tubing
(4), characterised by an expandable bag (11) located on the outside
(56) of the packer body (9), the bag (11) having an outwardly
facing semi-permeable wall (12) made from fabric, at least one
injection conduit (13) connecting the inside of the bag (11) and
one or more resin supplies, whereby an injection of a liquid
curable resin having an injection pressure from the resin supplies,
through the injection conduit(s) (13) and into the bag (11), causes
an expansion of the bag (11), the resin partly penetrates the
outwardly facing fabric wall (12) and seals against the well bore
wall (10), and after curing forms a packer seal (58).
2. A packer (7) according to claim 1, characterised by that the
resin supplies are formed by one ore more inlets (14, 15) on the
inside (57) of the packer body (9), and that the injection of the
liquid curable resin is done as an injection into the resin
inlet(s) (14, 15).
3. A packer (7) according to claim 1, characterised by that the
resin supplies are formed by two or more resin storage chambers
attached to or integral with the packer body, for storing two
components of a two component resin, and that the injection of the
liquid curable resin is done as emptying the resin storage chambers
through the resin conduit(s).
4. A packer (7) according to claim 1, characterised by that the
resin supplies are formed by one or more resin storage chambers
attached to or integral with the packer body, for storing one
component of a two component resin, and inlets (14, 15) on the
inside (57) of the packer body (9), and that the injection of the
liquid curable resin is done as emptying the one resin component
from the resin storage chamber(s), and injecting the other resin
component into the resin inlet(s) (14, 15).
5. A packer (7) according to any of the preceding claims,
characterised by a deformable packer mesh (16) located on the
outside of the bag (11), whereby the expansion of the bag (11)
deforms the mesh (16) and forces the mesh (16) against the well
bore wall (10), whereupon the resin which penetrates the outwardly
facing fabric wall (12) fills openings (17) in the mesh (16).
6. A packer (7) according to any of the preceding claims,
characterised by that the bag (11) is essentially annular, and
extends around the packer body (9).
7. A packer (7) according to any of the preceding claims,
characterised by that the expandability of the bag (11) is achieved
by the bag (11) being foldable and can assume a folded position in
which the outwardly facing fabric wall (12) is proximal to the
packer body (9) and an unfolded position in which the outwardly
facing fabric wall (12) is proximal to the well bore wall (10).
8. A packer (7) according to any of the preceding claims,
characterised by that the permeability of the fabric is dependent
upon the differential pressure across the fabric.
9. A packer (7) according claim 8, characterised by that the fabric
comprises elastic-plastic strands with a long elongation before
fracture, an increasing differential pressure across the fabric
thereby causes an elongation of the strands and expansion of pores
in the fabric and thus an increasing permeability of the fabric, an
increasing internal pressure from the resin in the bag (11) thereby
provides an increasing penetration of resin through the fabric.
10. A packer (7) according to claim 9, characterised by that the
fabric also includes stiff strands with a short elongation before
fracture, the fabric is adapted in such a way that the stiff
strands break when the bag (11) is subjected to an internal
threshold pressure, causing a sudden increase in the permeability
of the fabric.
11. A packer (7) according to any of the preceding claims,
characterised by that a static mixer (18) for mixing a
two-component resin is located in the injection conduit(s)
(13).
12. A packer (7) according claim 11, characterised by that the
injection conduit(s) (13) is/are formed by one or more longitudinal
channels of the packer body, and the static mixer(s) (18)
comprise(s) a plurality of oblique surfaces (19).
13. A setting tool for a packer according claim 1 or 2 or any of
the claims 5-12, to be lowered into the packer (7) by a drill
string or coiled tubing (20) when the packer (7) forms part of the
production tubing (4), for injecting two different resin components
into the resin inlet(s) (14, 15) of the packer body (9),
characterised by a connection (21) for connecting to the drill
string or coiled tubing (20), for supporting the setting tool and
supply of hydraulic control fluid from the drillstring or coiled
tubing (20), two resin chambers (23, 24) for storing two different
components of a two-component resin, a resin channel (25, 26)
extending from each resin chamber (23, 24) to a common or separate
resin outlet(s) (27, 28) on the outside of the setting tool, one
piston (29, 30) in each resin chamber (23, 24) and a piston rod
(31) which connects the pistons (29, 30), the pistons and the
piston rod are movable by the hydraulic control fluid, for a
proportional ejection of the two resin components, a positioning
device (35, 36) for positioning the resin outlet(s) (27, 28) of the
setting tool relative to the resin inlet(s) (14, 15) of the packer
body (9) when the setting tool enters the packer (7), radially
expandable annular seals (32, 33, 34) located on each side of the
resin outlet(s) (27, 28).
14. A setting tool according to claim 13, characterised by that the
radially expandable annular seals (32, 33, 34) are expandable by
the hydraulic control fluid.
15. A setting tool according to claim 13 or 14, characterised by a
pressure sensitive control valve (37, 38) which prevents the
hydraulic control fluid from moving the pistons (29, 30) and the
piston rod (31) until the pressure of the hydraulic control fluid
exceeds an opening pressure.
16. A setting tool according to any of the claims claim 13 to 15,
characterised by that the cylinders (45, 46, 63) of the resin
chambers (23, 24), the resin channels (25, 26), the pistons (29,
30) and the piston rod (31) are disposable.
17. A setting tool according to any of the claims 13-16,
characterised by that principal resin containing components (45,
46, 63, 29, 30) form part of a disposable cartridge.
18. A method for setting a packer (7) comprising a body (9) which
forms part of a production tubing (4) which is located in a well
bore (1), characterised by injecting a liquid curable resin having
an injection pressure in an expandable bag (11) located between the
packer body (9) and a wall (10) of the well bore (1), the bag (11)
having an outwardly facing semi-permeable wall (12) made from
fabric, the resin thereby fills and expands the bag (12) and partly
penetrates the fabric and seals against the well bore wall (10),
essentially maintaining the injection pressure during curing of the
resin, whereupon the resin after curing forms a packer seal (58).
Description
[0001] The invention relates to a packer to be included in a
production tubing in a well bore, for sealing against a wall of the
well bore, wherein the packer comprises an essentially cylindrical
packer body with connections for connecting to the production
tubing.
[0002] The invention also relates to a setting tool for a packer,
to be lowered into the packer by a drill string or coiled tubing
when the packer forms part of the production tubing, for injecting
two different resin components into resin inlet(s) of the packer
body.
[0003] The invention further relates to a method for setting a
packer comprising a body which forms part of a production tubing
which is located in a well bore.
[0004] In recovery of hydrocarbons from hydrocarbon reservoirs,
wells are drilled from the seabed or the surface of the earth, down
to the reservoir. The wells are lined with pipes designated casing
to prevent the well from collapsing. A production packer is placed
in the lower end of the casing, above the reservoir, and a pipe
designated production tubing is placed inside the casing, through
the production packer, for conveying the hydrocarbon flow from the
reservoir to the surface.
[0005] Some wells are drilled through more than one reservoir. In
such wells the tubing normally extends to the lower reservoir. In
order to control the inflowing from each reservoir, and sometimes
also at different places in the same reservoir, inlet valves are
included in the tubing at the desired locations. In order to obtain
an effective use of the inlet valves, it is required to prevent
hydrocarbons from flowing along the outside of the tubing, and
therefore the space between the tubing and the well bore wall is
either filled with concrete or sealed by a packer between each
inlet valve. Such a packer is known as an "external casing packer".
Whether the pipe in the reservoir area is designated casing or
tubing is a matter of terminology, or the configuration of the
well, and such a packer may thus as well be called an "external
tubing packer". The tubing consist of sections which are screwed
together, and each end of the packer has threads, in order to be
screwed in between two tubing sections. The packers are set by
expanding packing means of the packer, which is done by a setting
tool which is lowered into the packer and connected to the packer
for manipulating the packing means.
[0006] A known packer to be included in a production tubing in a
well bore comprises a hollow rubber element, which is inflated by a
curable fluid, e.g. a liquid resin or concrete, which is injected
by the setting tool. After injection, the concrete or resin cures
and keeps the rubber element in the inflated position, in which it
seals between the tubing and the well bore wall. This type of
packer is encumbered with the drawback that the rubber element may
be damaged during the installation or inflation. Further the
temperature, pressure and well fluids adversely influence the
integrity of the rubber, and therefor the lifetime of such a packer
is often shorter than desired. This type of packer is therefore
likely to leak.
[0007] In a production packer, and other packers intended for
sealing between the inner tubing and the outer casing, the sealing
is achieved by radially expandable mechanical packing means, which
may be hydraulically activated by a setting tool. Here the above
mentioned problems related to the inflatable rubber element do not
exist. These packers, do, however, require that the outer contact
surface, i.e. the inside of the casing, is circular. Although a
well is drilled by a circular bit, the well bore wall is far less
circular than the inside of the casing. Known packer designs which
are intended for sealing between the tubing and the casing are
therefore unsuitable to establish a proper seal between the tubing
and the well bore wall.
[0008] U.S. Pat. No. 4,057,118 A describes a packer comprising a
body with radially packing means for sealing between the packer and
the well bore wall, wherein the packer has rotatable connections
between the body and the tubing.
[0009] U.S. Pat. No. 6,006,836 describes a method for sealing a
plug in a pipe disposed in a well bore. A hardenable epoxy sealing
composition which hardens into a resilient solid mass is placed
into the pipe adjacent the plug, and then allowed to harden.
[0010] The object of the invention is to provide a packer to be
included in a production tubing in a well bore, for sealing against
a wall of the well bore, a setting tool for the packer and a method
for setting a packer comprising a body which forms part of a
production tubing which is located in a well bore, in which the
above discussed problems related to leakage are reduced or
eliminated.
[0011] The objects are achieved according to the invention by a
packer according to claim 1, a setting tool according to claim 13
and a method according to claim 18.
[0012] The invention thus relates to a packer to be included in a
production tubing in a well bore, for sealing against a wall of the
well bore, wherein the packer comprises an essentially cylindrical
packer body with connections for connecting to the production
tubing. The packer comprises an expandable bag located on the
outside of the packer body, which bag has an outwardly facing
semi-permeable wall made from fabric. The packer also comprises at
least one injection conduit which connects the inside of the bag
and one or more resin supplies. When setting the packer, a liquid
curable resin having an injection pressure is injected from the
resin supply or supplies, through the injection conduit(s) and into
the bag (11), which causes an expansion of the bag. The resin
partly penetrates the outwardly facing semi-permeable fabric wall
and seals against the well bore wall, and after curing the resin
forms a packer seal.
[0013] In one embodiment the resin supplies are formed by one or
more inlets on the inside of the packer body, and the injection of
the liquid curable resin is done as an injection into the resin
inlet(s). The injection into the resin inlet(s) may be done by a
setting tool which carries two components of a liquid curable
resin. The mixing of the two resin components may take place in the
packer or in the setting tool.
[0014] In another embodiment the resin supplies are formed by two
or more resin storage chambers attached to or integral with the
packer body, for storing two components of a two component resin.
In this embodiment the injection of the liquid curable resin is
done as emptying the resin storage chambers into the resin
conduit(s) and further into the bag. The emptying of the resin
storage chambers may be done by pistons which force the resin out
of the resin storage chambers. The pistons may be moved by means of
a pressurised hydraulic control liquid which is supplied from a
setting tool. In this embodiment the mixing of the two resin
components will have to take place in the packer.
[0015] In still another embodiment the resin supplies may be formed
by one or more resin storage chambers attached to or integral with
the packer body, for storing one component of a two component
resin, and inlets on the inside of the packer body. In this
embodiment the injection of the liquid curable resin is done as
emptying the one resin component from the resin storage chamber(s),
and injecting the other resin component into the resin inlet(s).
The emptying of the resin storage chamber(s) and the injection into
the resin inlet(s) may be done as discussed above. Also in this
embodiment the mixing of the two resin components will have to take
place in the packer.
[0016] Preferably a deformable packer mesh is located on the
outside of the bag, whereby the expansion of the bag deforms the
mesh and forces the mesh against the well bore wall, whereupon the
resin which penetrates the outwardly facing fabric wall fills
openings of the mesh.
[0017] In order to control the injection of resin into the well
bore, the permeability of the fabric is preferably dependent upon
the differential pressure across the fabric, i.e. an increasing
internal pressure in the bag is accompanied by an increasing
penetration of resin through the bag.
[0018] The invention also relates to a setting tool for a packer
according to the embodiment in which the resin supplies are formed
by one or more inlets on the inside of the packer body, and the
injection of the liquid curable resin is done as an injection into
the resin inlet(s). The setting tool comprises a connection for
connecting to a drill string or coiled tubing, for supporting the
setting tool and supply hydraulic control fluid from the drill
string or coiled tubing. The setting tool will be lowered into the
packer by the drill string or coiled tubing when the packer forms
part of the production tubing, for injecting two different resin
components into the resin inlet(s) of the packer body. The setting
tool also comprises two resin chambers for storing two different
components of a two-component resin, a resin channel extending from
each resin chamber to a common or separate resin outlet(s) on the
outside of the setting tool, one piston in each resin chamber and a
piston rod which connects the pistons. The pistons and the piston
rod are movable by the hydraulic control fluid, for a proportional
ejection of the two resin components. Further the setting tool
comprises a positioning device for positioning the resin outlet(s)
of the setting tool relative to the resin inlet(s) of the packer
body when the setting tool enters the packer. The setting tool also
comprises radially expandable annular seals located on each side of
the resin outlet(s), for sealing against the inside of the packer
body, and thereby isolate the resin outlet(s) of the setting tool
and the resin inlet(s) of the packer body.
[0019] The radial expansion of the annular seals may be provided by
mechanical means, e.g. a plurality of conical segments which are
forced in under the annular seals by a movement of the setting tool
in the well bore.
[0020] In order to provide a setting tool which can be operated in
a convenient way, it is, however, preferred that the annular seals
are expandable by means of the hydraulic control fluid.
[0021] The setting tool preferably comprises a pressure sensitive
control valve which prevents the hydraulic control fluid from
moving the pistons and the piston rod until the pressure of the
hydraulic control fluid exceeds an opening pressure. This opening
pressure is lower than the pressure which is required to expand the
radially expandable annular seals, and it is thereby ensured that
the radially expandable annular seals isolate the resin outlet(s)
and the resin inlet(s) before resin is injected from the setting
tool into the packer.
[0022] The invention further relates to a method for setting a
packer comprising a body which forms part of a production tubing
which is located in a well bore. The method comprises injecting a
liquid curable resin having an injection pressure in an expandable
bag located between the packer body and a wall of the well bore;
which bag has an outwardly facing semi-permeable wall made from
fabric. The resin thereby fills and expands the bag and partly
penetrates the fabric and seals against the well bore wall. Further
the method comprises essentially maintaining the injection pressure
during curing of the resin, whereupon the resin after curing forms
a packer seal.
[0023] When the bag is inflated, the bag displaces fluid which is
present in the well, and keeps the resin in place during curing.
The resin which penetrates the bag contacts the well bore wall and
seals against the well bore wall, and thus the resin fills and
seals the space between the tubing and the well bore wall. It is
thereby provided a packer in which problems related to leakage are
reduced or eliminated.
[0024] Further objects, preferred embodiments and advantages of the
invention will appear from the detail part of the description.
[0025] The invention will now be explained in more detail in
connection with a description of a specific embodiment, and with
reference to the drawings, in which:
[0026] FIG. 1 illustrates locations of packers according to the
invention in a well bore,
[0027] FIG. 2 illustrates a longitudinal section through a packer
according to the invention,
[0028] FIG. 3 illustrates a longitudinal section through a setting
tool according to the invention,
[0029] FIG. 4 illustrates the setting tool of FIG. 3 inserted in
the packer of FIG. 2, prior to setting of the packer,
[0030] FIG. 5 corresponds to FIG. 4, after setting of the
packer,
[0031] FIG. 6 illustrates the packer of FIG. 2 after setting,
[0032] FIG. 7 is a side view of a packer mesh according to the
invention, prior to the setting of the packer,
[0033] FIG. 8 is a side view of the packer mesh of FIG. 7, after
the setting of the packer.
[0034] FIG. 1 illustrates locations of packers 7 according to the
invention in a well bore 1. The well bore 1 has been drilled from a
surface, above FIG. 1, to drain various hydrocarbon reservoirs 2. A
casing 5 has been lowered into the well bore, to prevent the well
from collapsing. The casing 5 is terminated in a production packer
6 above the uppermost reservoir 2. A tubing 4 has been lowered into
the casing 5, through the production packer 6, and further down to
the reservoirs 2.
[0035] The reservoirs 2 are separated by non permeable strata 3,
and in order to obtain an optimum draining of the reservoirs, it is
required to control the inflowing from each reservoir 2. This
control is achieved by inlet valves 8, which are integral parts of
the tubing 4. In order to obtain an effective use of the inlet
valves 8, it is required to prevent hydrocarbons from flowing
between the reservoirs 2 along the outside of the tubing 4, and the
space between the tubing 4 and the well bore wall 10 is therefore
sealed by a packer 7 between each inlet valve 8. Like the inlet
valves 8, the packers 7 are integral parts of the tubing 4.
[0036] FIG. 2 illustrates a longitudinal section through a packer 7
according to the invention. The packer 7 is included in a
production tubing 4, which has been lowered into a well bore 1, as
discussed with reference to FIG. 1. The packer 7 comprises an
essentially cylindrical packer body 9, which is provided with not
illustrated threaded connections of a standard, well-known design,
by which it has been connected to not illustrated production tubing
4 (se FIG. 1) above and below the packer 7. Centralizers of a known
design are included as a part of the tubing 4 adjacent to the
packer 7, for keeping the packer 7 essentially in the centre of the
well bore 1. It is seen that the inside of the packer body 9 is
empty, and thus hydrocarbons are free to flow through the packer
7.
[0037] The packer 7 comprises an expandable bag 11 located on the
outside 56 of the packer body 9, which bag 11 has an outwardly
facing semi-permeable wall 12 made from fabric. An inner wall 60 of
the bag 11 faces the packer body 9, and may be attached to the
packer body 9, e.g. by gluing or a tight fit. The inner wall 60 may
be made of the same material as the outer wall 12, or the inner
wall may be made from a different material.
[0038] The packer 7 also comprises an injection conduit 13 which
connects the inside of the bag 11 and two resin inlets 14, 15 on
the inside 57 of the packer body 9. Further a deformable packer
mesh 16 is located on the outside of the bag 11. The packer will be
discussed in more detail after a description of the setting tool
and a discussion of the setting of the packer.
[0039] FIG. 3 illustrates a longitudinal section through a setting
tool according to the invention. The setting tool is designed for
injecting two different resin components of a two component liquid
curable resin into the resin inlets 14, 15 of the packer body
9.
[0040] The setting tool comprises a connection 21 for connecting to
a drill string or coiled tubing 20. In the illustrated embodiment
the connection 21 is a male connection with threads 41, which is
screwed into corresponding threads of a female connection 22 in the
lower end of a coiled tubing 20. The purpose of the coiled tubing
is to support the setting tool when it is lowered into the packer
body 9, and supply hydraulic control fluid from the surface, i.e.
from the outside of the well, to internals of the setting tool.
[0041] The setting tool comprises a first resin chamber 23 and a
second resin chamber 24 for storing a first and a second component,
respectively, of the two-component resin. The first resin chamber
23 is defined by a first cylinder 45 with an end portion 61, and a
first piston 29 opposite the end portion 61. The second resin
chamber 24 is defined by a second cylinder 46 with an end portion
62, and a second piston 30 opposite the end portion 62. The second
resin chamber 24 further has an inner cylinder 63, which is located
within and is integral with the second cylinder 46.
[0042] The first piston 29 is slideable supported inside the first
cylinder 45, and the second piston 30 is slideable supported inside
the inner cylinder 63. The pistons are thereby movable towards the
end portions 61, 62. A piston rod 31 connects the pistons 29, 30,
and when they move, the two pistons 29, 30 will therefore move the
same distance.
[0043] A first resin channel 25 extends from the first resin
chamber 23 to a first resin outlet 27 on the outside of the setting
tool, and a second resin channel 26 extends from the second resin
chamber 24 to a second resin outlet 28, also located on the outside
of the setting tool. The second resin channel 26 is partly formed
by an annular space between the inner cylinder 63 and the second
cylinder 46. The two resin outlets 27, 28 are closed by first and
second breakable seals 48, 49, respectively.
[0044] The setting tool further comprises a positioning device for
positioning the resin outlets 27, 28 of the setting tool relative
to the resin inlets 14, 15 of the packer body 9 when the setting
tool enters the packer 7. This positioning device is formed by a
radially movable dog 35 which is located in a recess 54 in a dog
body 51, which by means of threads 50 is screwed into the setting
tool body 39. A spring 36 biases the dog 35 into the position in
FIG. 3, in which the dog abuts against a shoulder 64 and projects
on the outside of the dog body 51. A setting tool head 53 is
attached to the dog body 51 by a threaded connection 52.
[0045] Further the setting tool comprises radially expandable
annular seals 32, 33, 34 located on each side of the resin outlets
27, 28. A control fluid channel 42 extends from a control fluid
inlet space 43, to the inside or underside of each annular seal 32,
33, 34. The annular seals are made from an elastomer and have the
form of lips, which in side areas 65 are fixed and sealed to the
body 39 of the packer body 9. A supply of hydraulic pressure to the
inside of the annular seals 32, 33, 34 will therefor expand the
seals in radial direction.
[0046] FIG. 4 illustrates the setting tool of FIG. 3 inserted in
the packer of FIG. 2, prior to setting of the packer. The setting
tool has been lowered down in the packer 7 by the coiled tubing 20.
During this lowering the dog 35 was forced into the recess 54 by
the inside 57 of the packer body 9. When the dog 35 arrived at a
positioning groove 55 in the packer body 9 (see FIG. 2), the spring
36 caused the dog 35 to enter the positioning groove 55, and
thereby position the setting tool relative to the packer 7. The
setting tool and the packer is adapted to bring the resin outlets
27, 28 of the setting tool in correspondence with the resin inlets
14, 15 of the packer body 9 when the dog 35 is in the positioning
groove 55.
[0047] After the positioning of the setting tool in the packer 7
follows the actual setting of the packer, which is the injection of
the resin. In order to ensure a proper transfer of resin from the
setting tool to the packer body 9, it is required first to isolate
the resin outlets 27, 28 and the resin inlets 14, 15. In the
illustrated setting tool this is achieved by a pressure sensitive
control valve which prevents the hydraulic control fluid from
moving the pistons 29, 30 and the piston rod 31 until the pressure
of the hydraulic control fluid exceeds an opening pressure.
[0048] The pressure sensitive control valve comprises a valve body
37 which by means of a valve spring 38 is biased against a valve
seat 59. When the pressure of the hydraulic control fluid in the
inlet space 43 exceeds the opening pressure, the valve body 37 is
forced away from the seat 59, and control fluid is allowed to pass
between the valve body 37 and the seat 59, through an opening 40 in
the valve body 37 and into a fluid space 44.
[0049] The radially expandable annular seals 32, 33, 34 can be
expanded by a pressure which is below the opening pressure for the
control valve, and thus the isolation of the resin outlets 27, 28
and the resin inlets 14, 15 prior to the injection of the resin is
done by first supplying hydraulic control fluid of a pressure below
the opening pressure from the coiled tubing 20 to the control fluid
inlet space 43. The fluid pressure will be transferred through the
control fluid channel 42 to the inside of the radially expandable
annular seals 32, 33, 34. This causes a radial expansion of the
seals 32, 33, 34 until they contact the inside 57 of the packer
body 9 and isolate the resin outlets 27, 28 and the resin inlets
14, 15.
[0050] Then follows the injection of the resin, which is done by
supplying hydraulic control fluid of a pressure above the opening
pressure for the control valve. The valve body 37 then moves away
from the seat 59, and the hydraulic control fluid flows to the
fluid space 44. The fluid pressure in the fluid space 44 forces the
first piston 29 down in the first cylinder 45, which causes a flow
of the first resin component from the first resin chamber 23 to the
first resin outlet 27, in which the first resin component is
injected into the first resin inlet 14. The piston rod 31 transfers
the movement of the first piston 29 to the second piston 30, which
moves down in the second cylinder 46. This causes a flow of the
second resin component from the second resin chamber 24 to the
second resin outlet 28, in which the second resin component is
injected into the second resin inlet 15. As a part of the
injection, the first and second breakable seals 48, 49 is broken by
the pressure of the resin. Since the two pistons 29, 30 due to the
piston rod 31 will move the same distance, the two resin components
will be ejected proportionally from the two resin outlets 27,
28.
[0051] For a further understanding, reference is made to FIG. 5,
which corresponds to FIG. 4, after setting of the packer.
[0052] From the resin inlets 14, 15 the two resin components flow
through the injection conduit 13 and into the bag 11. In the
illustrated embodiment, a static mixer 18 for mixing a
two-component resin is located in the injection conduit 13. The
injection conduit 13 is formed by a longitudinal channel in the
packer body 9, and the static mixer 18 comprises a plurality of
oblique surfaces 19, which ensure a proper mixing of the two liquid
resin components.
[0053] The injection of the resin causes an expansion, i.e. an
inflation, of the bag 11, as illustrated in FIG. 5. The resin
partly penetrates the outwardly facing fabric wall 12 and contacts
and seals against the well bore wall 10, and thus the resin fills
and seals the space between the packer body 9 and the well bore
wall 10.
[0054] Then follows the curing of the resin. In order to maintain
the inflation of the bag and ensure a good sealing effect, the
resin injection pressure is preferably maintained during the curing
of the resin. The injection pressure of the resin is controlled by
the pressure of the control fluid, which is supplied from the
surface, and thus the pressure of the control fluid is preferably
maintained during the curing. After curing the resin forms a packer
seal 58.
[0055] After the setting of the packer, the setting tool is lifted
out from the packer 7, and the packer remains in the set condition,
as illustrated in FIG. 6.
[0056] As mentioned, the illustrated packer 7 comprises a
deformable packer mesh 16 located on the outside of the bag 11. The
expansion of the bag 11 deforms the mesh 16 and forces the mesh 16
against the well bore wall 10, whereupon the resin which penetrates
the outwardly facing fabric wall 12 fills openings 17 in the mesh
16. The mesh 16 provides an armouring to the packer seal 58, and
reinforces the packer seal. The mesh 16 also serves as a spacer and
provides a distance between the bag 11 and the well bore wall 10,
which allows the formation of a differential pressure across the
fabric of the outwardly facing wall 12 during the inflation of the
bag 11. This differential pressure facilitates the penetration of
the resin through the fabric, and thus assists in the formation of
a good packer seal 58. Finally, the mesh 16 is protects the bag 11
when the tubing 4 with the packer 7 is lowered into the well bore
1, and thus this mesh 16 is very favourable.
[0057] FIG. 7 illustrates an embodiment of a packer mesh 16 in the
condition it has before expansion of the bag 11. The packer mesh 16
is formed by a cylindrical tube or sleeve made from metal sheet,
and is provided with regularly spaced longitudinal slits 17. The
metal sheet is deformable and has a long elongation before
fracture, and thus after the tube of FIG. 7 has been expanded by
the bag 11, it gets the shape of the mesh of FIG. 8, in which the
slits 17 have been widened out into openings 17.
[0058] In order to provide an even distribution of resin and a
packer seal with an essentially uniform thickness, the bag 11 is
preferably essentially annular, and extends around the packer body
9. The bag 11 can be glued to the packer body 9, or attached to the
packer by a tight fit. In order to ensure that resin can freely
flow into the bag 11, it is, however, preferred that the bag 11 in
some way is positively attached to the packer body in the area of
the inlet of the injection conduit 13.
[0059] In order to ensure a sealing effect between the bag 11 and
the packer body 9, it is preferred that also the inner wall 60 of
the bag or the complete bag is made of a semi-permeable fabric,
causing the resin to penetrate through the fabric of the inside of
the bag, and seal against the packer body 9.
[0060] The expandability of the bag from the position in FIG. 2 to
the expanded position in FIG. 6 can be achieved by the bag 11 being
foldable, and can assume a folded position in which the outwardly
facing fabric wall 12 is proximal to the packer body 9 and an
unfolded position in which the outwardly facing fabric wall 12 is
proximal to the well bore wall 10. The expandability can, however,
also be achieved by a bag which is made from an elastic or plastic
fabric.
[0061] When setting the packer, which may be located several
hundred metres, or even a couple of thousand metres below the
surface, it is important to be able to control the formation of the
packer seal 58. As discussed, this is partly done by the pressure
sensitive control valve, which does not allow ejection of resin
from the setting tool before the pressure is above an opening
pressure. A further control of the resin injection is achieved by a
bag in which the permeability of the fabric is dependent upon the
differential pressure across the fabric. This feature can be
achieved by a fabric which comprises elastic-plastic strands with a
long elongation before fracture. An increasing differential
pressure across the fabric thereby causes an elongation of the
strands and expansion of pores in the fabric and thus an increasing
permeability of the fabric. An increasing internal pressure from
the resin in the bag 11 thereby provides an increasing penetration
of resin through the fabric.
[0062] In another embodiment the fabric in addition to the
elastic-plastic strands also includes stiff strands with a short
elongation before fracture. The fabric is adapted in such a way
that the stiff strands break when the bag 11 is subjected to an
internal threshold pressure, which causes a sudden increase in the
permeability of the fabric. It is thereby achieved a bag with a
sudden increase in the permeability when the resin pressure exceeds
the threshold pressure. The resin pressure is provided by the
pressure of the hydraulic control fluid, which is controlled from
the surface, and it is thereby provided a convenient way of
controlling the formation of the resin packer seal.
[0063] Most fabrics have some sort of semi-permeability, and a
number of fabrics can be used. The permeability can be modified by
impregnation or surface treatment. A favourable fabric is made from
yarn of PA 6.6 High Tenacity LDPF, density 470 dTex 136 filament
(without twisting), with 21/21 strands per cm, binding 1/1, covered
by a silicone layer of 25 g/m2. This fabric is available from FOV
Fabrics AB, Bor{dot over (a)}s, Sweden.
[0064] A number of resins can be used. The curing process develops
heat. In order to reduce the development of heat, which can be
detrimental to the resin, a filler, which does not develop heat,
may be included in the resin. The filler can be included in the two
resin components. A favourable two-component resin is the "Araldite
Casting Resin System", comprising "Araldite CY 5995", "Hardener HY
925" and "Filler Silica Flour", which is available from Vantico UK,
Askim, Sweden.
[0065] After the setting of the packer, the setting tool will be
contaminated by resin, and a cleaning is cumbersome and may be
injurious to the operator's health. Therefore the cylinders 45, 46,
63 of the resin chambers 23, 24, the resin channels 25, 26, the
pistons 29, 30 and the piston rod 31 are preferably disposable.
Preferably the principal resin containing components, i.e. at least
the cylinders 45, 46, 63 of the resin chambers 23, 24 and the
pistons 29, 30 form part of a disposable cartridge. Such a
cartridge may also include the spacer ring 47 for keeping the
cylinders 45, 46 in place. The first and second resin channels 25,
26 with the resin outlets 27, 28 may be made from disposable pipe
inserts. A removal of the contaminated parts would then include
first removing the resin channels 25, 26, then unscrewing the dog
body 51 from the setting tool body 39, and withdraw the cartridge
from the inside of the setting tool.
[0066] The invention also relates to method for setting a packer 7
comprising a body 9 which forms part of a production tubing 4 which
is located in a well bore 1. This method comprises
[0067] injecting a liquid curable resin having an injection
pressure in an expandable bag 11 located between the packer body 9
and a wall 10 of the well bore 1, the bag 11 having an outwardly
facing semi-permeable wall 12 made from fabric, the resin thereby
fills and expands the bag 12 and partly penetrates the fabric and
seals against the well bore wall 10,
[0068] essentially maintaining the injection pressure during curing
of the resin, whereupon the resin after curing forms a packer seal
58.
[0069] For an explanation and a more detailed description of the
method according to the invention, reference is made to the above
description.
[0070] The invention has in the above been described with reference
to a specific embodiment. A number of variants are, however,
possible, e.g. related to the shape and number of the injection
conduit or conduits of the packer body, the resin channels of the
setting tool, and the number and location of resin inlets and
outlets of the packer body and the setting tool, respectively. A
specific example of such a variant is to mix the two resin
components in a static mixer in the setting tool, and then inject
the mixture into the packer body through a single resin inlet.
* * * * *