U.S. patent application number 14/128714 was filed with the patent office on 2014-07-31 for plug, and methods for setting and releasing the plug.
This patent application is currently assigned to ARCHER OIL TOOLS AS. The applicant listed for this patent is Tor Eivind Hansen, Krzysztof Klimas. Invention is credited to Tor Eivind Hansen, Krzysztof Klimas.
Application Number | 20140209321 14/128714 |
Document ID | / |
Family ID | 46650832 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140209321 |
Kind Code |
A1 |
Hansen; Tor Eivind ; et
al. |
July 31, 2014 |
PLUG, AND METHODS FOR SETTING AND RELEASING THE PLUG
Abstract
A plug includes a slip actuator for setting and release of
slips, and a locking element in contact with the slip actuator. The
locking element includes multiple parts with internal threads which
constitute an enclosure around threads of a pipe. On the radial
outer surface of the locking element are provided resilient
elements. When setting the plug, the locking element is capable of
sliding over the pipe threads for movement of the slip actuator and
setting of the slips, until the locking element comes into
engagement with a locking sleeve, fixed relative to the pipe, which
prevents rotation of the locking element. When releasing the plug,
the locking element is released from the locking sleeve, and the
locking element rotates off the pipe threads, and the slip actuator
follows the movement of the locking element and releases the
slips.
Inventors: |
Hansen; Tor Eivind;
(Sandnes, NO) ; Klimas; Krzysztof; (Sandnes,
NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hansen; Tor Eivind
Klimas; Krzysztof |
Sandnes
Sandnes |
|
NO
NO |
|
|
Assignee: |
ARCHER OIL TOOLS AS
Stavanger
NO
|
Family ID: |
46650832 |
Appl. No.: |
14/128714 |
Filed: |
June 25, 2012 |
PCT Filed: |
June 25, 2012 |
PCT NO: |
PCT/IB2012/053191 |
371 Date: |
February 4, 2014 |
Current U.S.
Class: |
166/377 ;
166/135; 166/386 |
Current CPC
Class: |
E21B 33/129 20130101;
E21B 33/134 20130101; E21B 23/06 20130101 |
Class at
Publication: |
166/377 ;
166/135; 166/386 |
International
Class: |
E21B 33/129 20060101
E21B033/129 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2011 |
NO |
20110908 |
Claims
1. A plug for a hydrocarbon well, wherein the plug can be held
fixed relative to a casing/borehole wall, and wherein the plug
further comprises: a slip actuator for setting and releasing slips,
a locking element in contact with the slip actuator, and one or
more resilient packing elements which are adapted for sealing
against the casing/borehole wall, wherein the locking element
comprises multiple parts having internal threads which constitute
an enclosure around threads on a pipe, and wherein on the radial
outer surface of the locking element there are arranged resilient
elements (6), and wherein the locking element, when setting the
plug, is capable of sliding over the pipe threads for movement of
the slip actuator and setting of the slips, and that the locking
element comes into engagement with a locking sleeve in order to
prevent rotation of the locking element; whilst when releasing the
plug, the locking sleeve is released from the locking element, the
locking element rotates off the pipe threads and the slips are
released.
2. The plug according to claim 1, wherein the plug is held fixed to
the casing/borehole wall by a holding member with radially acting
elements.
3. The plug according to claim 1, wherein the setting and the
release of the plug is controlled by axial movement of the
pipe.
4. The plug according to one of claim 1, wherein the holding member
is in end contact with a guide sleeve and that the locking element
is in end contact with the other end of the guide sleeve.
5. The plug according to claim 1, wherein a pin is provided on the
pipe which follows the movement of the pipe, the pin being movable
in a recess in the guide sleeve.
6. The plug according to claim 1, wherein the locking element and
the locking sleeve have corresponding locking grooves and locking
pins.
7. The plug according to claim 1, wherein the activation of the
setting of the plug is controlled by a first timer that is
activated by a specific pressure on the pipe over a given period of
time.
8. The plug according to claim 7, wherein the at least one timer is
hydraulic, and that the pressure acting on the timer controls the
transfer of hydraulic fluid from a first chamber to a second
chamber in the timer, and where the setting starts when all
hydraulic fluid has been transferred between the chambers.
9. The plug according to claim 1, wherein the activation of the
release of the plug is controlled by a second timer which is
activated by a specific pressure on the pipe over a given period of
time.
10. The plug according to claim 7, wherein the at least one timer
is hydraulic, and that the pressure that acts on the timer controls
the transfer of hydraulic fluid from a first chamber to a second
chamber in the timer, and where the release starts when all
hydraulic fluid has been transferred between the chambers.
11. The plug according to claim 1, wherein the resilient packing
elements are compressed by setting of the slips, and on the release
the resilient packing elements expand axially, this axial expansion
motion rotating the locking element off the pipe threads.
12. A method for setting the plug according to claim 1, wherein the
setting is activated by an axial movement of the pipe, wherein the
movement further causes a guide sleeve to apply a force on the
locking element which, by virtue of its high-pitch threads against
the pipe, will slide over the threads and exert a force on the slip
actuator which presses the slips out into firm engagement with the
casing/borehole wall.
13. A method for release of the plug according to claim 1, wherein
an axial movement of the pipe activates the release of the locking
sleeve from the locking element, such that the locking element is
free to rotate off the threads on the pipe and the slips are
released.
14. A method according to claim 13, wherein the locking element
rotates off the threads on the pipe in that resilient packing
elements on the plug expand axially and act on the locking element.
Description
INTRODUCTION
[0001] The present invention relates to a plug and to methods for
setting and releasing the plug in a well, for example, a
hydrocarbon well, as disclosed in the independent apparatus claim
and in the independent method claims.
BACKGROUND/PRIOR ART
[0002] It is common practice to close off the borehole, either
temporarily or permanently, by using plugs. The background for this
may be that it is desirable, for example, to carry out tests or
maintenance in the well. The plugs are usually run down the well
using a running tool. When the plug has reached the desired depth
in the well, it is secured to the surrounding casing or borehole
wall using anchoring elements. The borehole is subsequently sealed,
often by using packers which seal the area between the pipe or plug
and the borehole wall. The bridge plug shown in U.S. Pat. No.
6,220,348 B1, and the whole running tool, must be pulled out of the
well if another operation is to be carried out in the well, which
will mean a great deal of extra time and costs.
[0003] Known plugs for use in wells have the disadvantage that the
plugs require maintenance between each operation.
[0004] It is usual to set and release plugs by means of rotation,
but it can be difficult to achieve controlled rotation at great
well depths. There are several potential sources of error which
make the setting and release hazardous. One such source of error
could be left-hand (anti-clockwise) rotation, which may result in
equipment such as drill pipes or plugs being unscrewed from one
another.
[0005] It is an object of the invention to resolve some of the
drawbacks of the prior art. The object is achieved by means of a
plug and methods for its setting and release according to the
independent claims, with embodiments of the invention disclosed in
the dependent claims. The setting and release take place
essentially by means of axial movement of the pipe. By this is
meant that an up-and-down movement applied to the plug is
transmitted into a rotational movement that applies to the plug a
moment which it wishes to release through a locking system. Another
object is to provide a plug which can be used for several
operations in a well with little call for maintenance of the plug
between the different operations.
[0006] In the present invention, according to independent claim 1,
a plug for a hydrocarbon well is defined, wherein the plug can be
held in place relative to a casing/borehole, and wherein the plug
further comprises a slip actuator for setting and releasing slips,
a locking element in contact with the slip actuator, and one or
more resilient packing elements which are adapted for sealing
against the casing/borehole wall, and wherein the locking element
comprises multiple parts having internal threads which constitute
an enclosure around threads on a pipe, and where on the radial
outer surface of the locking element there are arranged resilient
elements, and that [0007] the locking element, when setting the
plug, is capable of sliding over the pipe threads for movement of
the slip actuator and setting of the slips, and that the locking
element comes into engagement with a locking sleeve to prevent
rotation of the locking element, [0008] whilst when releasing the
plug, the locking sleeve is released from the locking element, the
locking element rotates off the pipe threads and the slips are
released.
[0009] The invention also relates to a method for setting the plug
in a well, wherein the setting is activated by an axial movement of
the pipe, and where the movement further causes a guide sleeve to
apply a force on the locking element which, by means of its
high-pitch threads against the pipe, will slide over the threads
and exert a force on the slip actuator which presses the slips out
into firm engagement with the casing/borehole wall. By high-pitch
threads here is meant threads that will rotate off a corresponding
threaded part in only a few turns.
[0010] The invention relates also to a method for releasing the
plug wherein an axial movement of the pipe activates the release of
the locking sleeve from the locking element, such that the locking
element is free to rotate off the threads on the pipe and the slips
are released. Axial movement may be a movement up or down, or a
combination thereof.
[0011] The setting or release of the plug should not take place
unless desired. Up and down movement of the vessel, as a
consequence of the rolling of the sea, may inadvertently start the
setting. To avoid undesired setting and release, a first and a
second hydraulic timer may be provided in connection with the plug
for setting and release, respectively. The timers, one for setting
and one for release, ensure that the setting or release does not
start until the pressure from the surface acts over a given time
period. The timers each consist of two hydraulic fluid chambers,
where fluid from one of the chambers starts to flow over into the
other chamber as a result of pressure that is applied to the pipe
from the surface. If the pressure is not applied for a sufficiently
long time, as, for example, on the heave of the waves, all the
fluid will not flow between the chambers, and the setting or the
release will not be started. Once all the fluid has flowed between
the chambers, the setting or the release will start.
[0012] On the pipe there may be provided at least one fixed pin
that is movable in a recess in a guide sleeve on the plug. The
recess in the guide sleeve may be helical. This makes it possible
for the operator to know at all times where the plug is in the
setting or release process, in that the pin element follows the
axial movements of the pipe, up-down-up, as the pipe is pushed down
into the well or pulled upwards. An axial movement of the pipe, and
thus of the pin in the recess, will cause the axial movement to be
transmitted into a rotational movement of the guide sleeve
depending on the form of the recess.
[0013] A holding member with radially acting elements can hold the
plug essentially fixed to the casing/borehole wall during the
setting. During the setting, but not necessarily during the
release, the holding member will be in end contact with a guide
sleeve, and a locking element will be in end contact with the
second end of the guide sleeve.
[0014] In an embodiment, the setting involves that a locking
element with locking grooves, which during setting of the plug is
so arranged as to allow the locking element on an axial movement of
the pipe to slide over corresponding threads on the pipe, engages
with corresponding locking pins on the locking sleeve and is
prevented from being screwed off the threads. The locking sleeve is
held fixed in the rotational direction, but is movable in an axial
direction relative to the pipe. The configuration of the locking
grooves on the locking element and the locking pins on the locking
sleeve may be any configuration suitable to prevent rotation. On
locking, and before the locking element is locked in the locking
sleeve, the axial movement of the pipe will set slips, and the plug
will be anchored to the casing/borehole wall. Resilient packing
elements arranged on the plug seal against the casing/borehole wall
when compressed. In connection with the compressible resilient
packing elements, one or more backstop elements are provided which
are fixed relative to the pipe. The backstop elements follow the
movement of the pipe, and a further movement of the pipe, after the
slips have been set, will cause the resilient packing elements to
be compressed between the slips and the backstop elements.
[0015] When releasing the plug, the pipe is by means of the running
tool run down to the plug. A timer controls the activation of the
release. After the activation of the timer, the pipe is moved a
given length. This movement causes the slips to be released thereby
releasing the anchoring against the casing/borehole wall, and the
engagement between the locking grooves on the locking element and
the locking pins on the locking sleeve is broken. On release of the
slips, the holding force from the slips against the resilient
packing elements is removed. The resilient packing elements will
therefore no longer be kept compressed, but are free to expand in
an axial direction. The axial force from the resilient packing
elements will act on the locking element such that the locking
element rotates off the threads on the pipe.
DESCRIPTION OF THE INVENTION
[0016] One embodiment of the invention will now be described with
reference to the attached drawings, wherein:
[0017] FIG. 1 shows a plug coupled to a running tool and a pipe at
the start of setting;
[0018] FIG. 2 shows the setting according to FIG. 1 with the slips
out;
[0019] FIG. 3 shows the beginning of the release of the plug;
[0020] FIG. 4 shows the release of the plug;
[0021] FIG. 5 shows a locking element on the outer surface of a
pipe, and a locking sleeve;
[0022] FIG. 6A shows a pin arranged on a pipe, where the pin is in
a first position, movable in a recess on a guide sleeve;
[0023] FIG. 6B shows the pin in a second position, where the pipe
is pulled towards the surface;
[0024] FIG. 6C shows the position of the pin in the recess as the
setting process starts and the pipe is pushed downwards;
[0025] FIG. 6D shows the pin in its end position when the setting
process has been completed;
[0026] FIG. 7 shows the timer function of the present
invention.
DETAILED DESCRIPTION
[0027] Reference is first made to FIGS. 1-4, which show a plug 1
coupled to a running tool 13 and a pipe 15. The lower end of the
plug is shown to the right in the figure. The internal pipe of the
plug 1, the running tool 13 and the pipe 15 are referred to below
as pipe 15. At the lower end of the plug 1 there is arranged a
holding member 10 with radially acting elements 12 for holding the
plug fixed relative to the casing/borehole wall, see FIG. 2. There
is further shown a first 2 and a second 42 hydraulic timer which
control the activation of the setting and the release of the plug
1. Furthermore, a pin 3 is arranged on the lower end of the pipe
15. A guide sleeve 4, which is a part of the plug 1, has a recess
16 in which the pin 3 can move. Arranged in end contact with the
guide sleeve 4 is a rotatable locking element 5, consisting of
multiple parts, having internal high-pitch threads 17 capable of
engaging with corresponding high-pitch threads 18 on the radial
outer surface of the pipe 15, best shown in FIG. 5. Furthermore, on
the radial outer surface of the locking element 5 there are
resilient elements 6 which form an enclosure around the parts that
constitute the locking element 5.
[0028] The locking element 5 has arranged at one of its end
portions locking grooves 11 capable of engaging with corresponding
locking pins 19 in a locking sleeve 7. The locking sleeve 7 is
fixed in the rotational direction but is movable in an axial
direction, see FIG. 5. The locking grooves 11 on the locking
element 5 are formed of radially inward facing pins. The
corresponding locking pins 19 on the locking sleeve 7 consist of
axially projecting pins, which are locked in the locking grooves 11
on the locking element 5. On the radial outer surface of the
locking sleeve 7 is a slip actuator 8, which is capable of coming
into contact with the locking element 5, see FIGS. 1 and 2. The
slip actuator 8 has at least one conical end portion which is
adapted for pushing slips 9 out into engagement with the
casing/borehole wall in order to secure the plug 1 in the well.
[0029] At the upper end of the plug 1, resilient packers 20 are
provided which seal between the pipe 15 or plug 1 and the
casing/borehole wall. In connection with the resilient packing
elements 20, backstop elements 41 are arranged thereabove that are
fixed relative to the pipe 15 and follow the movement of the pipe
15.
Setting
[0030] FIGS. 6A-6D show, step by step, the position of the pin 3 in
the recess 16 during the process of setting the plug 1.
[0031] During the running down of the pipe 15, the pin 3 is in the
position shown in FIG. 6A. When the plug is at the desired depth in
the well, the running down of the pipe 15 with the attached running
tool 13 and the plug 1 is stopped, and the setting process starts.
The pipe 15 is pulled back slightly, and the pin 3 follows the
recess 16 to its next position in the guide sleeve 4 (FIG. 6B),
which causes the guide sleeve 15 to rotate as a result of the
movement of the pin 3 in the recess 16. Pressure is then applied
from the surface over a predetermined period of time whilst the
pipe 15 is run down. The pin 3 will then follow the pipe 15 and
come into the position shown in FIG. 6C, where the setting process
starts. The pipe 15 is subsequently pushed on downwards until the
pin 3 reaches the vertical end position in the recess 16 (FIG.
6D).
[0032] The time interval for how long pressure is to be applied to
the pipe 15 is determined in advance, and is given by how long it
takes before all fluid in the hydraulic timer 2 has migrated from
the first chamber to the second chamber, see FIG. 7. Such a time
period is, for example, set to at least 20 seconds so as to prevent
the axial movement of the pipe 15 from being confused with natural
heave motions of the vessel owing to the motion of the sea. The
first 2 and the second 42 hydraulic timer may therefore be regarded
as a dampener for the setting and release, respectively, as it
filters out the natural heave motions of the platform, and only
activates the setting and release of the plug when the pressure on
the pipe 15 has acted for at least as long as the predetermined
time period.
[0033] When all fluid has flowed over from one chamber to the other
chamber in the first hydraulic timer 2, the setting of the plug 1
starts. A holding member 10 with radially acting elements 12 on the
plug 1 essentially holds the plug 1 fixed to the casing/borehole
wall, see FIGS. 1-4. The pipe 15 is moved down and the pin 3
follows the vertical groove in FIGS. 6C and 6D in the recess 16 on
the guide sleeve 4, whilst the radially acting elements 12 on the
holding member 10 hold the plug 1 fixed relative to the
casing/borehole wall. The guide sleeve 4, wherein the pin 3 follows
the recess 16, is in abutment with the holding member 10 secured to
the casing/borehole wall, and will exert a force against the first
end of the above-lying locking element 5, see FIG. 2. The locking
element 5, which consists of multiple parts with internal
high-pitch threads 17, has resilient elements 6 on its outer
surface which enable the locking element 5 to slide over the
corresponding high-pitch threads 18 on the pipe 15, see FIG. 5. The
resilient elements 6 on the outer surface of the locking element 5
have as their only purpose to hold together the multiple parts
which constitute the locking element 5, and do not represent any
major force on the locking element 5 in the radial direction
against the pipe 15. This means that the internal threads 17 of the
locking element, during the setting of the plug 1, slide over the
threads 18 of the pipe 15, without being screwed on. The locking
element 5, at its other end, is in abutment with a slip actuator 8
which rests against the radial outer surface of the locking sleeve
7. An upwardly directed movement of the locking element 5 will
exert an upward movement on one end of the slip actuator 8. The
slip actuator 8 may be conical at its other end and an upward axial
movement of the slip actuator 8 will press the slips 9 out into
engagement with the casing/borehole wall, see FIG. 2. At the same
time, as can best be seen from FIG. 5, when the internal threads 17
of the locking element 5 essentially completely cover the pipe
threads 18, locking grooves 11 on the locking element 5 will engage
with corresponding locking pins 19 on the locking sleeve 7 and
ensure that the locking element 5 is held locked in the rotational
direction. The locking sleeve 7 is secured to the pipe 15 in the
rotational direction and rotational forces from the locking element
5 will be locked in the locking sleeve 7. The locking element 5 is
now secured to the locking sleeve 7, the slips 9 are in contact
with the casing/borehole wall, and the plug 1 is secured in the
well. The pin 3 in the recess 16 is now in the vertical end
position, as shown in FIG. 6D. After the slips 9 have been set and
the pin 3 has reached its vertical end position, pressure is again
applied from the surface on the pipe 15 such that the resilient
packing elements 20 are compressed between the secured slips 9 from
below and the backstop elements 41 from above. In this way, the
wellbore is sealed between the pipe 15 or the plug 1 and the
casing/borehole wall by the resilient packing elements 20. The pipe
15 with the attached running tool 13 can be released from the plug
1, and the plug 1 can be left in the well.
Release
[0034] When the plug is to be released from the casing/borehole
wall, the pipe 15 is run down into engagement with the plug by the
associated running tool 13, see FIG. 3. Pressure is then applied
from the surface over a given period of time such that the second
hydraulic timer 42 activates the release. When the running tool 13
is fastened to the plug 1, and the second hydraulic timer 42 has
activated the release, the pipe 15 is pulled up. The corresponding
locking grooves 11 and the locking pins 19 between the locking
element 5 and the locking sleeve 7 will be separated from each
other. The locking element 5 will now no longer exert any upward
force on the slip actuator 8. The slips 9 will therefore be
released from the casing/borehole wall. When the slips 9 are no
longer set, the resilient packing elements 20 will no longer be
subjected to any force from below from the slips 9, but only from
above by the backstop elements 41. The resilient packing elements
20 will therefore expand and act as a spring against the locking
element 5 and press on the locking element 5 in an axial direction
such that the locking element 5 rotates off the threads 18 on the
pipe 15. The radially acting elements 12 on the holding element 10
will furthermore be released from the casing/borehole wall and the
plug 1 is free to be removed from the well, see FIG. 4.
[0035] The invention has now been explained with reference to one
embodiment. A person of skill in the art will understand that
changes and modifications may be made to the embodiment described
which are within the scope of the invention as defined in the
attached claims.
* * * * *