U.S. patent application number 14/779848 was filed with the patent office on 2016-02-25 for a device for controlling and isolating a tool in the form of an expansible sleeve for isolating areas in a well.
This patent application is currently assigned to Saltel Industries. The applicant listed for this patent is SALTEL INDUSTRIES. Invention is credited to Romain Neveu, Samuel Roselier, Benjamin Saltel, Jean-Louis Saltel, Gwenael Tanguy.
Application Number | 20160053568 14/779848 |
Document ID | / |
Family ID | 48979891 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160053568 |
Kind Code |
A1 |
Saltel; Jean-Louis ; et
al. |
February 25, 2016 |
A DEVICE FOR CONTROLLING AND ISOLATING A TOOL IN THE FORM OF AN
EXPANSIBLE SLEEVE FOR ISOLATING AREAS IN A WELL
Abstract
The present invention relates to a device for controlling and
isolating a tool for isolating areas in a well which comprises: a
main inlet conduit which communicates with the inside of said
casing, and which is obturated by a first element able to form a
barrier to a fluid circulating in said casing, while yielding
beyond a first pressure, this conduit communicating, with two
auxiliary conduits, the ends of which join up in order to form an
outlet conduit, one of these auxiliary conduits, forming a first
chamber, while, in the other one, a second element is provided
forming a barrier, moveable between a first position and a second
position wherein said first position, said second element forming a
barrier and the wall of said second auxiliary conduit make between
them a sealed annular chamber in which prevails a so-called
<<isolation>> pressure, this chamber not communicating
with the outside, notably with the well.
Inventors: |
Saltel; Jean-Louis; (Le
Rheu, FR) ; Tanguy; Gwenael; (Pace, FR) ;
Roselier; Samuel; (Le Rheu, FR) ; Saltel;
Benjamin; (Le Rheu, FR) ; Neveu; Romain;
(Saint Senoux, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SALTEL INDUSTRIES |
Bruz |
|
FR |
|
|
Assignee: |
Saltel Industries
Bruz
FR
|
Family ID: |
48979891 |
Appl. No.: |
14/779848 |
Filed: |
March 11, 2014 |
PCT Filed: |
March 11, 2014 |
PCT NO: |
PCT/EP2014/054704 |
371 Date: |
September 24, 2015 |
Current U.S.
Class: |
166/179 |
Current CPC
Class: |
E21B 23/06 20130101;
E21B 33/126 20130101; E21B 34/063 20130101; E21B 33/127 20130101;
E21B 34/06 20130101 |
International
Class: |
E21B 33/126 20060101
E21B033/126 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2013 |
FR |
1352768 |
Claims
1. A device for controlling and isolating a tool in the form of an
expansible sleeve for treating a well or a duct, this tool being
connected to a casing for supplying a pressurized fluid and is
inserted between said casing and the wall of said well or of the
duct, which comprises: a main inlet conduit which communicates with
the inside of said casing, and which is obturated by a first
element able to form a barrier to a fluid circulating in said
casing, while yielding beyond a first predetermined pressure of
said fluid, this conduit communicating, downstream from said
element forming a barrier, with two auxiliary conduits positioned
in parallel, the ends of which join up in order to form an outlet
conduit which opens inside the tool, one of the auxiliary conduits,
called<<first conduit>> forming, notably with said
first element, a first chamber in which prevails an isolation
pressure, while in the other one, called <<second
conduit>>, a second element is provided, forming a barrier
moveable between a first position in which it obturates this second
conduit while clearing the communication between the first conduit
and the outlet conduit, and a second position in which it prevents
any communication between the auxiliary conduits and the outlet
conduit, the passing from one position to the other being
accomplished by increasing the fluid pressure to a second
predetermined pressure greater than said first pressure, wherein in
said first position, said second element forming a barrier and the
wall of said second auxiliary conduit make between them a sealed
annular chamber wherein a so-called <<isolation>>
pressure also prevails, this chamber not communicating with the
outside, notably with the well.
2. The device according to claim 1, wherein said second element
comprises a piston constantly urged towards said second
position.
3. The device according to claim 1, wherein said second element
includes a frangible part, such as a pin, positioned in the sealed
chamber and which yields when the second predetermined pressure is
attained.
4. The device according to claim 1, wherein said isolation pressure
is equal to atmospheric pressure or is slightly greater.
5. The device according to claim 1, wherein said second element
includes a metal <<nose>> which, in said second
position, is in contact with the wall of the outlet conduit, also
in metal, the assembly thereby forming a metal/metal seal.
6. The device according to claim 1, wherein an anti-return valve is
positioned inside the outlet conduit.
7. The device according to claim 6, wherein the seal of said valve
is ensured by a metal/metal contact.
8. The device according to claim 1, wherein said expansible sleeve
is in metal.
9. The device according to claim 3, wherein it includes means for
acoustically recording the breakage of the barrier-forming elements
and means for recording the pressure in the annular space.
10. The device according to claim 9, wherein said recording means
may be queried remotely via RFID technology.
Description
[0001] The present invention relates to a device for controlling
and isolating a tool in the form of an expansible sleeve for
treating a well or a duct, this tool being connected to a casing
for supplying a pressurized fluid and is inserted between said
casing and the wall of said well or duct.
[0002] Expressed differently, it relates to a device at the bottom
of a well, allowing isolation of the upstream space from the
downstream space of an annular region comprised between a casing
and the formation (i.e. the rock of the subsoil) or else between
this same casing and the inner diameter of another casing already
present in the well. This isolation has to be made while preserving
the integrity of the whole of the casing (casing string) of the
well, i.e. the steel column comprised between the formation and the
well head.
[0003] It will be noted that a distinction has to be made between
the integrity of the annular space and the integrity of the casing,
both being essential for the integrity of the well.
[0004] The aforementioned annular space is generally sealed by
using cement which in liquid form is pumped into the casing from
the surface, and then injected into the annular space. After
injection, the cement hardens and the annular space is sealed.
[0005] The cementation quality of this annular space is of very
great importance for the integrity of the wells.
[0006] Indeed, this seal protects the casing from areas with salted
waters which the subsoil contains, which may corrode them and
damage them, causing possible loss of the well.
[0007] Moreover, this cementation protects the aquifers from the
pollution which may be caused by close formations containing
hydrocarbons.
[0008] This cementation forms a barrier protecting the risks of
blowout caused by high pressure gases which may migrate into the
annular space between the formation and the casing.
[0009] In practice, there exist many reasons which may result in an
imperfect cementation process, such as the large well size, the
horizontal areas thereof, difficult circulation or areas with loss.
The result of this is a poor seal.
[0010] It will also be noted that the wells are increasingly deep,
that most of them are drilled <<offshore>> at the
vertical of water heights which may attain more than 2,000 m, and
that the latest hydraulic fracturation technologies in which the
pressures may attain more than 15,000 psi (1,000 bars), subject
these sealed annular areas to very high stresses.
[0011] From the foregoing, it is clear that cementation of the
annular space(s) is particularly important and any weakness in
their making, while the pressures at play are very great (several
hundreds of bars), may cause damages which may lead to the loss of
the well and/or cause very substantial environmental damages.
[0012] The pressures in question may stem: [0013] from the inside
of the casing towards the outside, i.e. from the inside of the well
towards the annular space; [0014] from the annular space towards
the inside of the casing.
[0015] The casing (or casing string), the length of which may
attain several thousand meters, consists of casing tubes, with a
unit length comprised between 10 and 12 m, and assembled to each
other through sealed threadings.
[0016] The nature and the thickness of the material making up the
casing are calculated in order to withstand very great inner burst
pressures or outer collapse pressures.
[0017] Further, the casing should be sealed during the whole
lifetime of the well, i.e. for several tens of years. Any leak
detection systematically leads to repairing or to abandoning the
well.
[0018] The design, i.e. the configuration of the completion of the
well should minimize the risks of communication between the inside
and the outside of the casing. Also, the watch points are notably
the following: [0019] withstand the internal and external pressure
stresses; [0020] use steels compatible with the environment in
order to avoid risks of corrosion; [0021] use screwed and sealed
connection means; [0022] avoid communications between the inside
and the outside or, if this is not the case, produce a seal with
one or two barriers, if possible by metal/metal contact.
[0023] Technical solutions are presently available in order to
manage to make said annular space impervious.
[0024] Also, one of the techniques consists of positioning a
deformable membrane around the casing at the desired location. The
membrane is then deformed permanently, under the pressure of an
inflating fluid, against the wall of the formation. As the membrane
produces a seal on this wall, the annular space between the wall of
the formation and the wall of the casing is then made impervious.
This membrane may be in metal or elastomer, either reinforced or
not with fibers.
[0025] Regardless of the type of membrane, the inflation of the
latter requires the presence of a conduit for circulating the
inflating fluid between the inside of the membrane and the inside
of the casing. This circulation may be accomplished directly or via
a system which may include from one to three valves according to
the state of the art.
[0026] To the knowledge of the applicant, there exist 2 main
possible configurations illustrated in the diagrams which are the
subject of the appended FIGS. 1 and 3A.
[0027] According to a first technique illustrated in FIG. 1, a
metal membrane 3 is positioned around a casing 2, pre-positioned in
a well 1, and the inside of the membrane 3 is supplied with
inflating fluid directly through a conduit 200 crossing the wall 20
of the casing 2.
[0028] If the pressure is increased inside the casing 2 until it
attains a threshold giving the possibility of starting deformation
of the metal membrane 3, the latter being directly connected to the
casing 2, the membrane 3 deforms permanently. When the pressure
decreases, the metal membrane retains its shape definitively.
[0029] A first drawback of this technique results from the fact
that in the case of a failure of the metal membrane 3 leading to a
loss of its imperviousness, direct communication between the
annular space and the casing 2 is created.
[0030] A second drawback lies in the fact that in the case of
multiple laying of membranes 3 as illustrated in FIGS. 2A and 2B,
if the level of the hydrostatic pressure is identical in the casing
2 and in the annular space EA, then, when the pressure of the
inflating fluid increases in the casing 2, the three membranes 3,
distributed around the casing 2 and which may be separated by
several hundred meters, are simultaneously deformed while inflation
of the membranes one after the other from bottom to top, has more
advantages, in particular with the view of ensuring the best
possible cementation.
[0031] Individual inflation of each membrane 3 one after the other
is not controllable in this configuration.
[0032] Further, after the laying, each membrane 3 continues to be
subject to pressurization/depressurization cycles which might occur
during the life of the well 1, embrittling the membranes 3, a
little more at each cycle.
[0033] According to a second technique illustrated in FIG. 3A, the
deformable membrane 3 consists of an elastomer either reinforced or
not with fibers.
[0034] If this membrane 3 were directly connected to the casing 2
like in the previous case, it would deform elastically when the
pressure in the casing 2 increases and it would regain a condition
close to its initial shape as soon as the pressure decreases, by
its elasticity.
[0035] It is therefore necessary to insert between the inside of
the casing 2 and the inside of the membrane 3, a system of simple
or multiple valve(s) 4 (illustrated here surrounded by an oval)
giving the possibility of preserving and isolating the pressurized
volume inside the elastomeric membrane 3 at the end of the
inflating.
[0036] The pressure at the end of inflating is then determined by
the closing of the isolation valve 4. Once this valve is closed,
the membrane 3 can neither be emptied nor filled.
[0037] Further, in the case considered above of laying several
membranes 3 on a same casing 2 at different depths or in order to
avoid any inadvertent inflation, this system of multiple valves is
provided in order to allow control of the beginning of the
inflating of each membrane 3.
[0038] This system, for greater control, may even be completed by a
frangible pin, called a <<knock-out plug>>, which opens
the communication of the casing towards the control and isolation
valves by breaking it, most often by having a ball circulate in the
casing. But the insertion of the ball brings an additional
constraint.
[0039] In order to produce these systems of multiple valves,
analysis of the state of the art shows two different architectures:
one uses sliding pistons, while the second uses sliding sleeves. In
both cases, the pistons or sleeves are associated with breaking
parts giving the possibility of controlling the opening or the
closing of the pistons or sleeves, i.e. controlling the beginning
and the end of the inflating of the inflatable membrane.
[0040] Such a system of valves is also advantageous in the case of
a metal membrane in order to avoid inflating the membrane
inadvertently and isolating it from changes in pressures of the
casings, once it has been deformed.
[0041] Examples of such technologies equipped with filling valves
are described in patents or patent applications US 2003/0183398,
U.S. Pat. No. 4,260,164 and WO 2011/160193.
[0042] Such systems of metal or elastomer membranes, either
reinforced or not, equipped with multiple valves, have several
categories of drawbacks.
[0043] Firstly, these are drawbacks related to the expansible
elastomeric membrane. Indeed, this membrane has time-limited
strength and robustness. The isolation of the annular space between
the upstream and downstream portions of the well cannot therefore
be guaranteed in the long run.
[0044] Moreover, the loss of imperviousness of this membrane
generates a weakened area with the inside of the well by removing a
barrier.
[0045] Other drawbacks are related to the system of valves.
[0046] Thus, FIG. 3B is an enlargement of the system of valves 4
placed under the membrane 3 in FIG. 3A.
[0047] This system is a possible configuration typically consisting
of two sliding valves 40 which may either be sliding pistons or
sliding sleeves. These valves are placed in the conduit which puts
the inside of the casing 2 in communication with the inside of the
membrane 3.
[0048] Before inflating, one of the valves 40 is an obstacle to the
inflating fluid. It is only possible to break this first barrier by
increasing the pressure of the inflating fluid in the casing 2
beyond a certain pressure difference P1 predefined by a calibrated
breaking element, the pressure difference occurring between the
pressure of the casing and the pressure of the annular space. Once
this difference P1 has been exceeded, the first barrier is broken
and lets the inside of the casing 2 communicate with the inside of
the membrane 3.
[0049] This breakage marks the beginning of the phase for inflating
the membrane 3. The pressure is increased in the casing 2 in order
to continue with inflating the membrane 3.
[0050] The end of the inflating is marked by the release of the
movement of a second valve 40 in the casing-membrane communication
conduit which will be an obstacle to the return of the pressurized
fluid, in the direction from the membrane 3 to the casing 2. The
movement of this valve is released by the breaking of a calibrated
element, dimensioned so as to break as soon as the pressure
difference between the membrane and the annular space exceeds a
threshold P2 greater than P1. If the pressure further increases in
the casing, the membrane 3 cannot be further inflated.
[0051] Further, once the inflating is finished, as soon as the
pressure decreases, a return element brings the first valve 40 back
to its initial position so as to form a second barrier in the
communication conduit between the casing 2 and the membrane 3. Both
valves are then in their final state as illustrated by FIG. 3B.
[0052] Thus, analysis of the prior art shows that all the devices
for opening and closing the valves are activated by a pressure
difference between the inside of the casing and the annular space
comprised between the casing and the wall of the well.
[0053] Further, the seals of these valves 40 being subject to this
casing/annular space pressure difference, whether they consist of a
sliding piston or of sliding sleeves, are ensured by joints, noted
as J in FIG. 3C and 3D, these joints being most often elastomeric
joints.
[0054] When the breaking elements maintaining the valves 40 in
place break, the sudden movements releasing the pistons or sleeves
may damage these joints J. The seal at these valves is then no
longer ensured, thereby creating direct communication between the
casing 2 and the annular space EA (see FIG. 3C) or direct
communication between the annular space EA and the membrane 3 (see
FIG. 3D). In the latter case, if the membrane 3 is in an elastomer
either reinforced or not with fibers, it deflates.
[0055] Moreover, no device gives the possibility of ensuring:
[0056] that the triggerings for opening and then for closing the
valves have actually been accomplished; [0057] that the seal of the
annular space between the upstream and downstream portions of the
well is effective over time.
[0058] Moreover, the stresses related to the integrity of the wells
become increasingly large, whether this occurs at the level of the
isolation: [0059] of the annular space between the upstream and the
downstream portions of the well; [0060] between the inside and the
outside of the casing.
[0061] Preservation of the environment, public opinion,
regulations, production of increasingly numerous wells for
exploiting non-conventional resources forces this sector of
technology to increasingly ensure that this seal is efficient,
sustainable and controllable over several years.
[0062] The object of the present invention is precisely to propose
a device which gives the possibility of avoiding this
situation.
[0063] Thus, the present invention relates to a device for
controlling and isolating a tool in the form of an expansible
sleeve for treating a well or a duct, this tool being connected to
a casing for supplying a pressurized fluid and is inserted between
said casing and the wall of said well or of the duct, which
comprises: [0064] a main inlet conduit which communicates with the
inside of said casing, and which is obturated by a first element
capable of forming a barrier to a fluid circulating in said casing,
while yielding beyond a first predetermined pressure of said fluid,
[0065] this conduit communicating, downstream from said first
element forming a barrier, with two auxiliary conduits positioned
in parallel, the ends of which join up in order to form an outlet
conduit which opens into the inside of the pool, [0066] one of
these auxiliary conduits, said to be a <<first
conduit>>, notably forming with said first element, a first
chamber in which prevails an isolation pressure, while in the
other, called<<second conduit>>, a second element
forming a barrier is provided, moveable between a first position in
which it obturates the second conduit while leaving clear
communication between the first conduit and the outlet conduit, and
a second position in which it prevents any communication between
the auxiliary conduit and the outlet conduit, the passing from one
position to the other being accomplished by the breaking of a pin
under the effect of the increase in the pressure of the fluid up to
a second predetermined pressure, greater than said first pressure,
characterized by the fact that in said first position, said second
element forming a barrier and the wall of said second auxiliary
conduit make between them a sealed annular chamber wherein a
so-called<<isolation pressure>> also prevails, this
chamber not communicating with the outside, notably with the
well.
[0067] According to other non-limiting and advantageous features of
the invention: [0068] said second element comprises a piston
constantly urged towards said second position; [0069] said second
element includes a frangible part, such as a pin, positioned in the
sealed chamber and which yields when the second predetermined
pressure is attained; [0070] said isolation pressure is equal to
atmospheric pressure or is slightly greater; [0071] said second
element includes a metal<<nose>> which, in said second
position, is in contact and provides a seal with the wall of the
outlet conduit, also in metal; [0072] an anti-return valve is
positioned inside the outlet conduit; [0073] the seal of said valve
is ensured by a metal/metal contact; [0074] said expansible sleeve
is in metal; [0075] the device includes means for acoustically
recording the breaking of the elements forming a barrier and means
for recording the pressure in the annular space; [0076] said
recording means may be remotely polled via an RFID technology.
[0077] Other features and advantages of the invention will become
apparent upon reading the detailed description which follows. In
addition to
[0078] FIGS. 1 to 3D on which comments have already been made
above, reference will be made to the appended drawings wherein:
[0079] FIGS. 4A and 6B are simplified views, in a longitudinal
sectional view, of a well portion equipped with a casing with an
expansible sleeve and with the device according to the invention;
and
[0080] FIGS. 4B, 5 and 6A are more detailed, enlarged longitudinal
sectional views of an embodiment of the device;
[0081] FIGS. 7A and 7B are sectional views similar to those of
[0082] FIGS. 4A and 6B further illustrating detection means;
[0083] FIGS. 8A to 8D show in a longitudinal sectional view, a well
portion, the casing of which is equipped with several sleeves.
[0084] FIG. 4A illustrates a sectional view of a casing 2
positioned in the well 1 before cementation.
[0085] This casing is equipped with a deformable membrane 3 in
metal which is provided with the control and isolation device
illustrated here surrounded by an oval. A case allowing the
recording of the breakages of the elements of the control device
forming a barrier on the one hand and of a pressure of the annular
space placed above the metal membrane, i.e. inserted between this
membrane and the surface, on the other hand.
[0086] The control and isolation device includes a conduit C, this
conduit including a burst disc and two anti-return valves V1 and
V2, one of which is equipped with a frangible element F. The space
between the burst disc and the valve V1 delimiting a chamber CH1 is
at a pressure substantially equal to atmospheric pressure, and the
device also includes a second isolated chamber CH2 at a pressure
substantially equal to atmospheric pressure.
[0087] The disc, the valves V1 and V2, the element F are not
illustrated in FIG. 4A: these elements will be described in more
detail hereafter, notably with reference to FIG. 4B, including an
enlargement of the control and isolation device.
[0088] As already stated above, the device comprises a main inlet
conduit C which communicates with the inside of the casing 2 via a
drilled hole 200 opening into the wall 20 of the casing. The
conduit C is obturated by a first disc-shaped element 5, for
example in metal, which is able to form a barrier to a fluid
circulating in the casing, while yielding beyond a first
predetermined fluid pressure P1.
[0089] This conduit C opens into a chamber 60, the cylindrical wall
of which is referenced as 600.
[0090] Via this chamber, the conduit C communicates with two
auxiliary conduits 6 and 8 positioned in parallel, the end of which
join up in order to form an outlet conduit 9 which opens into the
inside of the tool 3.
[0091] One of these auxiliary conduits, a so-called<<first
conduit>> 8, includes an inlet 80 and an outlet 81 which
extends perpendicularly to the axis of the casing.
[0092] The inlet 80 opens into the chamber 60, while the outlet 81
slightly opens upstream from the two anti-return valves when they
are in the closed position.
[0093] This first auxiliary conduit 8 forms a first chamber. The
chamber 60 is part of the second auxiliary conduit 6 and has, from
upstream to downstream, i.e. from left to right, when FIG. 4B and
the fluid flow direction, a first cylindrical segment 61 with a
wall 610, of a small diameter, an intermediate segment 62 of larger
diameter and with a wall 620, an intermediate region of which 630
has a diameter slightly larger, are considered. As this will be
seen later on, this wall contributes to delimiting a second chamber
CH2.
[0094] The segment 62 substantially continues with the same
diameter as its inlet, but includes a section restriction which
makes it join the outlet conduit 9. Inside the conduit 6, an
anti-return valve V1 is positioned, which consists of a piston 7
having an elongated body 71.
[0095] In its upstream portion, it includes a head 70 having a
longitudinal recess 700 in which a coil spring R extends. This
spring is supported on the upstream end of the segment 62 and tends
to push the piston from upstream to downstream.
[0096] The head 70 is peripherally provided with a joint J, which
ensures a perfect seal between the piston and the segment 62 of the
conduit 6.
[0097] Downstream from the recess 700, the body 7 is crossed right
through by a frangible element or pin F which, as this will be seen
later on, is intended to break under the effect of a pressure P2
greater than P1. For this purpose, it has regions of lower
strength.
[0098] In its downstream portion, the piston continues with a nose
72, the diameter of which is substantially equal to that of the
corresponding segment of the conduit 6. It is also provided with a
seal gasket J similar to the previous one, and with a truncated end
surface 720, the function of which will be explained later on.
[0099] The outlet conduit 9 from downstream to upstream has a
segment 90 with a wall 900, which opens inside a conduit of smaller
diameter 91, and with a wall 910 in which a coil spring is
positioned. This spring bears against a bead B which forms an
anti-return valve obturating a segment 92 with a still smaller
diameter, which itself communicates with the conduits 6 and 8.
[0100] A frustroconical transition area 930 makes the upstream end
of the outlet conduit 9 communicate with the auxiliary conduit
6.
[0101] We shall now explain the operation of the device according
to the invention.
[0102] FIG. 4B illustrates a preliminary situation in which the
device has not yet been lowered into the well.
[0103] Before lowering it into the well, water is circulated in the
casing 2 so that the inside of the inflatable membrane 3 is filled
with water, this for avoiding its collapse by the increase in
pressure of the well during its lowering.
[0104] Of course, to do this, the burst disc 5 is not yet installed
and the water may then cover the inlet conduit C, the auxiliary
conduit 8 and then the outlet conduit 9 by pushing the bead B
against the spring R.
[0105] During this phase, the chamber CH2 delimited by the segment
63 of the conduit 6 and the piston 7 is at atmospheric pressure and
does not fill with water. It will indeed be noted that at this
stage, any passing of fluid into the conduit 6 is impossible since
the piston 7 is immobilized by the frangible pin F, and the piston
plus pin assembly being maintained in position by a return spring
R.
[0106] In order to close the assembly with the burst disc 5, a
portion of the water, circulating in the chamber CH1 delimited by
the conduit 8 and the segments 80, 81, 60, 61, 62 and 92, is purged
so that the filling of this chamber is for a major part ensured by
air at atmospheric pressure.
[0107] Once the assembly is in place in the well 1, the pressure
inside the casing 2 increases and becomes clearly greater than
atmospheric pressure.
[0108] As long as the pressure difference between the casing 2 and
atmospheric pressure in the chamber CH1 remains below the pressure
P1 for breaking the disc 5, the assembly of the device remains
closed and the deformable membrane 3 cannot inflate.
[0109] In order to inflate this membrane, the pressure again needs
to be increased inside the casing 2 from the surface by pumping
until the pressure difference is sufficient for breaking the disc
5. The predetermined pressure P1 has then been attained, which is
the pressure for breaking the disc.
[0110] Under these conditions, the conduit portion 62 is filled
with liquid but the valve V1 is always blocked by the presence of
the frangible finger F.
[0111] On the other hand, the fluid flows through the conduit 8 as
well as through the valve V2, since the fluid pressure is
sufficient for pushing back the bead B against the spring R.
[0112] The breaking of the disc 5 corresponds to the beginning of
the inflating of the membrane 3. This breaking may be acoustically
detected and recorded by a case provided for this purpose and
positioned close to the surroundings of the membrane.
[0113] The situation of FIG. 5 is then again found, wherein, except
for the chamber CH2 which remains at a pressure substantially equal
to atmospheric pressure since it is isolated with two joints J, the
remainder of the conduits is at the inflating pressure.
[0114] The pressure is then increased until the pin F is broken,
which corresponds to the position of FIG. 6A. A predetermined
pressure P2 for breaking the calibrated pin has then been attained,
the pressure P2 being greater than the pressure P1. Consequently,
the pin no longer opposes the movement of the piston 7, which is
released and pushed back from upstream to downstream under the
effect of the return spring R.
[0115] However, this sliding is limited since the nose 72 of the
piston 7 comes into contact with the inlet of the outlet conduit 9
by metal/metal contact of the frustroconical surfaces 720 and
930.
[0116] In this way, the membrane 3 can no longer be inflated. It
cannot either be deflated because of the presence of the valve V2
since the bead B bears against its seat.
[0117] Subsequently, when the pressure of the casing is purged and
the latter returns to its hydrostatic pressure level, the whole of
the conduits upstream from the valve V2 returns to the pressure of
the casing.
[0118] If the pressure inside the casing were to increase again,
for example in order to inflate another membrane, the valve V1
would remain in the closed position and therefore the membrane 3
would remain also completely isolated.
[0119] Thus, the end of the expansion is marked by the breakage of
the pin which gives the possibility of closing the access path in
the direction from the casing to the deformable membrane, while
releasing the movement of an anti-return valve. This valve is
maintained in its closed position by means of a spring. When the
pin is broken, the valve moves and sets the chamber initially at
atmospheric pressure to the pressure of the casing. Both joints J
then no longer have any function.
[0120] The breakage of the pin may be acoustically detected and
recorded by a case provided for this purpose and positioned in the
surroundings of the membrane.
[0121] At the end of the inflating, the membrane remains at its
inflating pressure and for each valve, the seal is guaranteed by a
metal/metal contact.
[0122] This situation is illustrated by FIG. 6B which illustrates a
schematic diagram of the membrane+control and isolation device
assembly after inflating the membrane.
[0123] The conduit C now includes 2 anti-return valves which are
opposed to each other, the chamber, initially at atmospheric
pressure, is now at the pressure of the casing and is no longer of
any use.
[0124] In FIG. 7A, the case BO giving the possibility of recording
the breakages of the elements of the barrier-forming control device
on the one hand and the long term changes in the pressures of the
annular space EA on the other hand, is placed above the metal
membrane, i.e. inserted between this membrane 3 and the surface or
between two membranes 3.
[0125] In the case of multiple laying of membranes 3 for a same
casing 2, each membrane will be equipped with a case BO placed as
close as possible to the membrane 3 with which it is associated.
Each case BO then allows detection and recording of the breakages
of the disc 5 and of the pin F, the breaking of the disc indicating
that the pressurized filling of the membrane has properly taken
place, while the breaking of the pin indicates that the inflating
was finished and that the membrane is isolated.
[0126] The case also allows recording of possible pressure
variations in the annular space for several years after laying the
membrane.
[0127] For this purpose, the case BO is advantageously placed above
the membrane 3 since it gives the possibility for example, in the
case of imperfect cementation under the membrane leading to a loss
of the seal of the cement along the wall of the formation, of
checking whether the metal membrane 3 has ensured its role by
sealing the annular space EA situated between the membrane 3 and
the surface of the well 1.
[0128] The case BO, if it records the pressure variations of the
annular space, therefore has a risk of possible communication
between the inside of the case and the annular space EA. Still, for
the sake of ensuring the integrity of the casing 2 relatively to
the annular space EA, the case BO is therefore detached from the
membrane 3 and from the control device. The disc 5 and pin F
breakages are acoustically detected remotely by the case BO placed
at a few tens of centimeters.
[0129] According to FIG. 7B, as the case BO is able to be queried
over a short distance by using RFID technology, the querying of the
case BO and the recovery of the data may be accomplished in the
well 1 before or after laying the membrane 3 by using a tool A
provided for this purpose and connected from the surface through
a<<wireline>> cable for example.
[0130] The advantages related to the creation of a reference
pressure chamber for triggering the breakage of weak points at
atmospheric pressure are the following: the reference pressure is
not the pressure of the well, so that a conduit has been removed
between the inside of the casing 2 and the annular space of the
well 1.
[0131] Moreover, any risk of leaks between the inside of the facing
2 and this annular space EA is suppressed at this control
device.
[0132] Further, upon opening the access valve between the inside of
the casing and the inside of the expansible structure, the opening
pressure is exclusively related to the pressure in the casing.
[0133] According to FIGS. 8A, 8B, 8C and 8D, if in the well there
exist several devices of this kind, because of the hydrostatic
pressure which increases with the depth and since the reference
pressure is substantially equal to atmospheric pressure, they will
naturally open from bottom to top, which will avoid generations of
traps for the fluid.
[0134] The advantages related to the creation of a valve with a
metal-on-metal seal associated with an anti-return bead essentially
lie in the fact that this seal is made without using elastomeric
gaskets, whence better durability over time.
[0135] Moreover, the seal is proportional to the applied pressure,
and the more the pressure increases, the more the seal is
efficient.
[0136] The use of a metal disc 5 makes it long-lasting over time
and makes it have a very high imperviousness level.
[0137] Finally, the advantages related to the setting into place of
an electronic system for recordings and measurements via RFID are
of being informed on the proper execution of the opening and
closing process of the inflating valve, and of a possible
measurement over time of the pressure in the annular space.
* * * * *