U.S. patent application number 13/516882 was filed with the patent office on 2012-11-08 for method and device for closing a well.
Invention is credited to Per Lund, Svein H. Solversen.
Application Number | 20120279706 13/516882 |
Document ID | / |
Family ID | 44167516 |
Filed Date | 2012-11-08 |
United States Patent
Application |
20120279706 |
Kind Code |
A1 |
Solversen; Svein H. ; et
al. |
November 8, 2012 |
METHOD AND DEVICE FOR CLOSING A WELL
Abstract
A method and device close a well with a casing in a formation in
the ground are provided. The method has the steps of moving a
cutting tool down into the well; removing a longitudinal portion of
the casing by cutting the longitudinal portion into pipe wall
pieces; removing the cutting tool; and setting a plug against the
formation in the longitudinal portion from which the casing has
been removed.
Inventors: |
Solversen; Svein H.; (Tau,
NO) ; Lund; Per; (Vestre Amoy, NO) |
Family ID: |
44167516 |
Appl. No.: |
13/516882 |
Filed: |
December 14, 2010 |
PCT Filed: |
December 14, 2010 |
PCT NO: |
PCT/NO2010/000459 |
371 Date: |
July 16, 2012 |
Current U.S.
Class: |
166/285 ;
166/55.7 |
Current CPC
Class: |
E21B 29/06 20130101;
E21B 33/146 20130101 |
Class at
Publication: |
166/285 ;
166/55.7 |
International
Class: |
E21B 33/13 20060101
E21B033/13; E21B 29/06 20060101 E21B029/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2009 |
NO |
20093545 |
Claims
1. A method of closing a well in a formation in ground in which a
casing is arranged, the method comprising the steps of: moving a
cutting tool down into the well; cutting openings across a
longitudinal portion of the casing; removing the cutting tool; and
filling a curable mass into the casing , wherein the curable mass
flows through the openings, filling a space between the casing and
the formation to form a full cross-sectional plug, wherein the pipe
wall pieces remain in the wall.
2. The method in accordance with claim 1, further comprising the
step of cutting the openings via a fluid jet.
3. (canceled)
4. The method in accordance with claim 1, further comprising the
step of: filling a lower portion of the well with a filler; cutting
an inner casing at a lower position in the well than a position at
which the longitudinal portion is located; and removing an upper
portion of the inner casing.
5. The method in accordance with claim 1, further comprising the
step of connecting the cutting tool to a surface of the well via
coiled tubing.
6. A cutting tool for closing a well in a formation in ground in
which a casing is arranged, the tool comprising a nozzle head
rotatable around its longitudinal axis, with at least one nozzle,
where the nozzle head is connected to coiled tubing, the coiled
tubing extending to a surface of the well, and the cutting tool
being connected to the casing by an anchor.
7. The cutting tool of claim 6, wherein the anchor is a rolling
anchor.
8. (canceled)
9. The cutting tool of claim 6, wherein the nozzle head is provided
with a pendulum nozzle.
10. The cutting tool of claim 6, wherein the cutting tool is
provided with a change-over valve which is arranged to selectably
connect a fluid flow to a desired nozzle.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a method of closing a well in the
ground. More particularly, it relates to a method of closing a well
in the ground wherein the well has a casing. The invention also
includes a device for practising the method.
[0002] When production from a ground well, particularly a petroleum
well, has been discontinued, it is necessary to close the well in a
way that protects against future outflow of well fluid and other
substances from the well.
[0003] Above each pressure-bearing zone, it is common practice to
place at least two independent barriers; including a suitable
plugging material which is arranged to seal the well. In some
cases, it is necessary to remove a section in the longitudinal
direction of a casing in order for a barrier or a plug to be placed
against the formation wall.
[0004] According to the prior art, the casing material is machined
away by means of a hard-metal blade which is arranged on a pipe
string. The pipe string is connected to a drilling vessel or an
installation with the necessary drilling equipment. Chips from the
machining must be transported up to the surface because the chips,
which may be magnetic and may include relatively long chip coils,
prevent tools from passing the portion if they are not removed.
[0005] Machining the longitudinal portion away from the casing by
means of the prior art may take several days and is a very
expensive operation.
SUMMARY OF THE INVENTION
[0006] One of the objectives of the invention is to remedy or
reduce at least one of the drawbacks of the prior art.
[0007] The objective is achieved in accordance with the invention
through the features which are specified in the description below
and in the claims that follow.
[0008] A method is provided for closing a well with casing in a
formation in the ground. The method has the steps of:
[0009] moving a cutting tool down into the well;
[0010] removing a longitudinal portion of the casing by cutting the
longitudinal portion into pipe wall pieces;
[0011] removing the cutting tool; and
[0012] setting a plug against the formation in the longitudinal
portion from which the casing has been removed.
[0013] The cutting tool may be a tool which is arranged to make
cuts through the pipe wall as opposed to machining tools which are
arranged to remove pipe material by chipping.
[0014] By cutting the longitudinal portion into pipe wall pieces,
the production of voluminous chips is avoided. Alternatively, the
pipe wall pieces that are produced are relatively easy to
handle.
[0015] Further, the method may involve cutting the longitudinal
portion by means of a fluid jet. By using a fluid jet, the further
induction of magnetic forces into the pipe wall pieces is avoided
and the pipe wall pieces may be allowed to fall down and remain in
the well. If desired, the pipe wall pieces may be carried to the
surface, for example, by means of a magnet.
[0016] The method may further have the steps of:
[0017] filling the lower portion of the well with filler;
[0018] cutting an inner casing at a lower position in the well than
the position at which the longitudinal portion is located; and
[0019] removing the upper portion of the inner casing.
[0020] The method may further have the step of connecting the
cutting tool to the surface by means of coiled tubing. The method
thereby makes it possible for the well to be shut down without the
use of a drilling rig.
[0021] The method can be practiced by means of a cutting tool for
cutting the longitudinal portion of a casing. The cutting tool may
have a nozzle head rotatable around its longitudinal axis. The
nozzle head has at least one nozzle and is connected to coiled
tubing. The coiled tubing may extend to the surface, and the
cutting tool is connected to the casing by means of an anchor.
[0022] The anchor may be a fixed anchor or a rolling anchor, and
the cutting tool may be provided with an actuator for moving the
nozzle head axially.
[0023] In an embodiment in which the anchor is fixed, the actuator
may be used for axial movement of the nozzle head during the
cutting operation. If a rolling anchor is used, the coiled tubing
can be moved axially in the well without the use of a separate
actuator.
[0024] In a further embodiment, the cutting head may be provided
with a pendulum nozzle. The pendulum nozzle, which is of a design
known in the art, is arranged to pivot the fluid jet while the
nozzle head is kept stationary.
[0025] The cutting tool may be provided with a change-over valve
which is arranged to selectively direct a fluid flow to a desired
nozzle. For example, the fluid flow may be directed to a cutting
nozzle during the cutting operation and then directed to a cleaning
nozzle during a subsequent cleaning operation.
[0026] The method and device according to the invention enable a
considerable reduction in the time spent on closing petroleum wells
while, at the same time, using considerably simpler equipment
compared with the prior art. The invention thereby provides for a
substantial reduction in costs connected with closing and finishing
off wells.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The following is a description of an example of a preferred
embodiment which is visualized in the accompanying drawings, in
which:
[0028] FIG. 1 shows schematically a well which has been prepared
for a cutting operation according to the invention.
[0029] FIG. 2 shows schematically a section, on a larger scale, of
a cutting head.
[0030] FIG. 3 shows a cutting pattern in the wall of the
casing.
[0031] FIG. 4 shows schematically, on a smaller scale, a well after
a plug has been set.
DETAILED DESCRIPTION OF THE INVENTION
[0032] In the drawings, the reference numeral 1 indicates a
petroleum well in a formation 2. An inner casing 4, a second inner
casing 6 and other casings B are cemented into a borehole 10 by
means of a cementation mass 12.
[0033] A seal 14 is created between the inner casing 4 and the
second inner casing 6.
[0034] In FIG. 1, the well 1 is shown after preparatory work has
been carried out. The preparatory work may involve filling the
lower portion of the inner casing 4 with filler 16, cutting the
inner casing 4, and removing the upper portion (not shown) of the
inner casing 4 from the well 1.
[0035] Coiled tubing 18 with a cutting tool 20 fitted thereon is
shown in the well 1. The cutting tool 20 may be positioned and held
fixed inside the second inner casing 6 by means of an anchor
22.
[0036] The cutting tool 20 includes a tool housing 24 with
necessary components known in the art, not shown, for controlling
the cutting operation. An actuator 26 is arranged to move a
rotatable nozzle head 28 in the longitudinal direction of the well
1.
[0037] In this preferred embodiment, the nozzle head 28 includes a
change-over valve 30 for selectively directing pressure fluid,
which is supplied via an actuator channel 32, from the coiled
tubing 18 to a cutting nozzle 34 or a cleaning nozzle 36, as shown
in FIG. 2.
[0038] The change-over valve 30 may be a so-called sequence valve
which changes its position every time the fluid pressure is
relieved.
[0039] When the cutting tool 20 is positioned in the well 1, the
cutting may be initiated by fluid containing abrasive material
flowing to the cutting nozzle 34 at a relatively high pressure via
the coiled tubing 18 and the change-over valve 30.
[0040] The nozzle head 28 moves the cutting nozzle 34 along a
predetermined path forming, for example, the cutting path 38 in the
pipe wall 40 of the second inner casing 6 as it is shown in FIG.
3.
[0041] By subsequently cutting along the paths 42, pipe wall pieces
44 are formed from the longitudinal portion 46 of the second inner
casing 6.
[0042] By switching the change-over valve 30, pressure fluid is
carried to the cleaning nozzle 36, resulting in the pipe wall
pieces 44 being washed down or into the well 1.
[0043] The part of the cementation mass 12 that may be behind the
longitudinal portion 46 of the second inner casing 6 is also
removed by means of fluid jets from the nozzles 34, 36 of the
nozzle head 28.
[0044] After the well 1 has been prepared, the coiled tubing 18 and
the cutting tool 20 are pulled from the well 1, after which a plug
48 is set against the formation 2 in the longitudinal portion 46 in
a manner known in the art, as shown in FIG. 4. In the present
embodiment, a rubber type plug 48 is shown. A person skilled in the
art will understand that any suitable plug may be used.
[0045] In an alternative method, not shown, the longitudinal
portion 46 may be chosen to be a location at which two or more
casings 6, 8, one outside another, will have to be cut away to
expose the formation 2.
[0046] Although exemplary systems, methods, and structures are
described in language specific to structural features and/or
methodological acts, the subject matter defined in the appended
claims is not necessarily limited to the specific features or acts
described. Rather, the specific features and acts are disclosed as
exemplary forms of implementing the claimed systems, methods, and
structures.
* * * * *