U.S. patent application number 12/624569 was filed with the patent office on 2010-06-24 for dump bailer.
Invention is credited to Malcolm Atkinson, Martin Innes, David MacWilliam, Jonathan Murty.
Application Number | 20100155054 12/624569 |
Document ID | / |
Family ID | 40547829 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100155054 |
Kind Code |
A1 |
Innes; Martin ; et
al. |
June 24, 2010 |
DUMP BAILER
Abstract
A dump bailer is disclosed herein comprising a tool body
defining a chamber for containing a material to be deposited and an
outlet in the tool body through which the material can be
deposited. The dump bailer also comprises a piston assembly
slideably mounted in the chamber and comprising a swabbing piston,
a supply of pressurized fluid, and a valve for releasing the
pressurized fluid to act on the swabbing piston to drive it along
the chamber to expel material contained therein through the
outlet.
Inventors: |
Innes; Martin; (US) ;
Murty; Jonathan; (US) ; MacWilliam; David;
(US) ; Atkinson; Malcolm; (US) |
Correspondence
Address: |
SCHLUMBERGER OILFIELD SERVICES
200 GILLINGHAM LANE, MD 200-9
SUGAR LAND
TX
77478
US
|
Family ID: |
40547829 |
Appl. No.: |
12/624569 |
Filed: |
November 24, 2009 |
Current U.S.
Class: |
166/165 |
Current CPC
Class: |
E21B 27/02 20130101 |
Class at
Publication: |
166/165 |
International
Class: |
E21B 27/02 20060101
E21B027/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 28, 2008 |
EP |
08170190.6 |
Claims
1. A dump bailer, comprising: a tool body defining a chamber for
containing a material to be deposited; an outlet in the tool body
through which the material can be deposited; and a piston assembly
slideably mounted in the chamber and comprising a swabbing piston,
a supply of pressurized fluid, and a valve for releasing the
pressurized fluid to act on the swabbing piston to drive it along
the chamber to expel material contained therein through the
outlet.
2. The dump bailer as claimed in claim 1, wherein the valve is
operable to direct pressurized fluid to act directly on the
swabbing piston.
3. The dump bailer as claimed in claim 1, wherein the supply of
pressurized fluid comprises a reservoir carried on the swabbing
piston so as to be moveable therewith.
4. The dump bailer as claimed in claim 1, further comprising an
intermediate mechanism through which the pressurized fluid can act
on the swabbing piston.
5. The dump bailer as claimed in claim 4, wherein the piston
assembly comprises a first stage piston slideably mounted in the
tool body, and a second stage piston that is slideably mounted in
the first stage piston, the second stage piston being connected to
the swabbing piston, the valve operating to release pressurized
fluid between the first and second stage pistons to drive the
swabbing piston along the chamber.
6. The dump bailer as claimed in claim 5, wherein a sliding seal is
provided on an inner wall of the tool body, and the first stage
piston comprises a head end that seals against the inner wall of
the tool body, and a tail end that has a smaller diameter than the
head end and seals in the sliding seal.
7. The dump bailer as claimed in claim 6, wherein the supply of
pressurized fluid comprises a reservoir defined between the head
end of the first stage piston and the sliding seal on the tool
body.
8. The dump bailer as claimed in claim 7, wherein sliding movement
of the first stage piston in the tool body causes the reservoir to
change in volume.
9. The dump bailer as claimed in claim 6, further comprising an
opening in the tool body such that the interior of the tool body
below the sliding seal is open to ambient pressure.
10. The dump bailer as claimed in claim 9, wherein the interior of
the tool body above the head end of the first stage piston is open
to ambient pressure.
11. The dump bailer as claimed in claim 9, wherein the pressurized
fluid is pressurized by the effect of the ambient pressure acting
on it.
12. The dump bailer as claimed in claim 9, wherein the tool body
further comprises a supplementary supply of pressurized fluid
connected to the interior of the tool body above the head end of
the first stage piston by means of a valve.
13. The dump bailer as claimed in claim 5, wherein the second stage
piston is mechanically connected to the swabbing piston, and the
first stage piston defines a cylinder in which the second stage
piston is mounted and into which the valve can release pressurized
fluid to drive the second stage piston along the cylinder which in
turn drives the swabbing piston along the chamber.
14. The dump bailer as claimed in claim 13, wherein the portion of
the cylinder below the second stage piston is maintained at an
internal pressure that is less than the pressure of the fluid in
the supply when the tool is in an ambient operating pressure
environment.
15. The dump bailer as claimed in claim 1, wherein the outlet
comprises a relief valve that is normally held in a shut position
until the pressure in the chamber rises above an opening pressure
due to the action of the swabbing piston.
16. The dump bailer as claimed in claim 1, wherein the outlet
comprises an end fitting having an opening in a predetermined
azimuthal position on the tool circumference.
17. The dump bailer as claimed in claim 1, wherein the end fitting
has a number of openings at azimuthal positions on the tool
circumference.
18. The dump bailer as claimed in claim 16, wherein the end fitting
is freely rotatable.
19. The dump bailer as claimed in claim 18, further comprising a
drive mechanism to rotate the end fitting, the drive mechanism
being powered by the flow of fluid from the chamber.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is based on and claims priority to
European Patent Application No. EP08170190, filed Nov. 28,
2008.
TECHNICAL FIELD
[0002] The present disclosure relates generally to a borehole tool
assembly for use in depositing materials in boreholes drilled in an
underground formation. More particularly, but not by way of
limitation, the present disclosure relates to dump bailers for use
in boreholes such as oil and gas wells.
BACKGROUND ART
[0003] Dump bailers have been developed to remove debris or solids
deposits from the wellbore prior to completing some other task, or
to obtain a sample of the fluid from the area of a downhole device,
by utilizing a suction action similar to a bicycle pump. Later
developments of bailers became available to deposit cements or
chemicals into a wellbore by simply reversing the action. However,
these bailers do not positively displace their contents in the true
sense, typically relying on gravity.
[0004] A dump-bailer tool normally includes a tubular chamber for
storing the cement slurry and a ported valve for the slurry to
discharge from the dump-bailer into the subterranean wellbore.
Dump-bailer tools are well known in the oil and gas industry. They
essentially include a thin walled concentric fluid chamber
consisting of threaded bailer tube sections. The upper end of the
tubes is connected mechanically to an armored or solid cable that
is spooled on a surface winch. The lower end of the tool consists
of electrical and/or mechanical dump release mechanisms, for
example a bull-plug which supports and confines the cement slurry
during conveyance into the wellbore. The bull-plug consists of a
valve device or rupture plug, which is initiated at the proper dump
depth by human interface, either electrically, hydraulically, or
mechanically initiated.
[0005] In one example, the dump bailer method expels the cement
slurry at a bridge plug or other barrier device in the well casing,
possibly above perforations to the reservoir formation through the
casing, prior to making new perforations. The slurry volume
capacity of the dump-bailer device is limited by the length and
internal diameter of the bailer tubes. Typical dump-bailer
volumetric capacities range from one to six imperial gallons (four
to twenty-eight liters). After each dump of slurry, the dump bailer
is retrieved to the surface and prepared for subsequent dump-bail
operations.
[0006] Of the gravity feed systems available, most use a glass or
ceramic disc to retain the cement which is either broken with an
explosive charge or by a pin when the tool is set-down. Gravity
feed systems are not as desirable as they tend to leave some cement
in the tool which then "strings" out as the tool is pulled out of
hole. More runs might be needed to achieve the correct amount of
cement for the desired plug strength (differential strength).
[0007] Positive displacement dump bailer systems have been
previously proposed. These typically run on electric line and
release a weight onto a piston which applies a pressure shock
through the cement which shears a pin at the bottom of the bailer
which allows the cement to fall out the bottom of the bailer either
under its own weight or with the additional weight of the actuating
system. One known device uses a motor to release the weight and
another uses a solenoid. One variation uses an explosive bolt which
has a similar function as the solenoid. Another known bailer is
activated either by a timer or by a pressure transducer, but again
only uses gravity to displace the contents to the wellbore.
[0008] Examples of various prior art documents in this field,
include U.S. Pat. No. 2,591,807; U.S. Pat. No. 2,689,008; U.S. Pat.
No. 2,696,258; U.S. Pat. No. 2,725,940; U.S. Pat. No. 2,994,378;
U.S. Pat. No. 3,187,813, U.S. Pat. No. 3,202,961; U.S. Pat. No.
3,208,521; U.S. Pat. No. 3,273,647; U.S. Pat. No. 3,318,393; U.S.
Pat. No. 3,379,251; U.S. Pat. No. 6,966,376; and, EP 1,223,303.
[0009] It is to rectifying these and other shortcomings of the
current art that the present invention is directed. Therefore, the
present disclosure is directed to providing a wireline tool
assembly which provides true positive displacement of its contents
into the borehole and that does not rely on gravity alone in which
to do so.
BRIEF DISCLOSURE OF THE INVENTION
[0010] In view of the foregoing disadvantages, problems, and
insufficiencies inherent in the known types of methods, systems and
apparatus present in the prior art, exemplary implementations of
the present disclosure are directed to a new and useful dump
bailer.
[0011] In at least one aspect, the dump bailer comprises: a tool
body defining a chamber for containing a material to be deposited;
an outlet in the tool body through which the material can be
deposited; and a piston assembly slideably mounted in the chamber
and comprising a swabbing piston, a supply of pressurized fluid,
and a valve for releasing the pressurized fluid to act on the
swabbing piston to drive it along the chamber to expel material
contained therein through the outlet.
[0012] In one embodiment, the valve is operable to direct
pressurized fluid to act directly on the swabbing piston. In this
case, the supply of pressurized fluid can comprise a reservoir
carried on the swabbing piston so as to be moveable therewith.
[0013] Another embodiment further comprises an intermediate
mechanism through which the pressurized fluid can act on the
swabbing piston.
[0014] The piston assembly can comprise a first stage piston
slideably mounted in the tool body, and a second stage piston that
is slideably mounted in the first stage piston, the second stage
piston being connected to the swabbing piston, the valve operating
to release pressurized fluid between the first and second stage
pistons to drive the swabbing piston along the chamber.
[0015] Preferably, a sliding seal is provided on an inner wall of
the tool body, and the first stage piston comprises a head end that
seals against the inner wall of the tool body, and a tail end that
has a smaller diameter than the head end and seals in the sliding
seal.
[0016] The supply of pressurized fluid can comprise a reservoir
defined between the head end of the first stage piston and the
sliding seal on the tool body and sliding movement of the first
stage piston in the tool body can cause the reservoir to change in
volume.
[0017] It is preferred that there is an opening in the tool body
such that the interior of the tool body below the sliding seal is
open to ambient pressure. The interior of the tool body above the
head end of the first stage piston can open to ambient pressure or
a supplementary supply of pressurized fluid can be connected to the
interior of the tool body above the head end of the first stage
piston by means of a valve. Preferably the pressurized fluid is
pressurized by the effect of the ambient pressure acting on it.
[0018] The second stage piston is typically mechanically connected
to the swabbing piston, and the first stage piston defines a
cylinder in which the second stage piston is mounted and into which
the valve can release pressurized fluid to drive the second stage
piston along the cylinder which in turn drives the swabbing piston
along the chamber.
[0019] In this case, the portion of the cylinder below the second
stage piston can be maintained at an internal pressure that is less
than the pressure of the fluid in the supply when the tool is in an
ambient operating pressure environment.
[0020] The outlet typically comprises a relief valve that is
normally held in a shut position until the pressure in the chamber
rises above an opening pressure due to the action of the swabbing
piston.
[0021] In one preferred embodiment, the outlet comprises an end
fitting having an opening in a predetermined azimuthal position on
the tool circumference. In another, the end fitting has a number of
openings at azimuthal positions on the tool circumference. The end
fitting can be freely rotatable. In which case a drive mechanism to
rotate the end fitting powered by the flow of fluid from the
chamber can be provided.
[0022] The piston system of the present invention is preferably
driven by pressure differentials, for example between ambient
operating pressure and reduced pressure in the tool, or elevated
pressures in to tool.
[0023] Further aspects of the invention will be apparent from the
following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Certain embodiments of the present invention will hereafter
be described with reference to the accompanying drawings, wherein
like reference numerals denote like elements, and:
[0025] FIG. 1 depicts one embodiment of a dump bailer according to
an aspect of the invention utilizing ambient pressure as a drive
force;
[0026] FIG. 2 depicts an alternative embodiment of a dump bailer
according to the invention utilizing compressed gas as a drive
force;
[0027] FIGS. 3 and 4 depict variations of the embodiment of FIG. 1
having different end fittings at the outlet;
[0028] FIGS. 5 and 6 depict an alternative embodiment of an
embodiment of the invention comprising an actuator which utilizes
compressed gas; and,
[0029] FIG. 7 depicts a triggering device according to an aspect of
the invention.
MODE(S) FOR CARRYING OUT THE INVENTION
[0030] One embodiment of the invention is shown in FIG. 1, in which
the dump bailer comprises a ram assembly is designed to operate by
using the difference between surrounding wellbore fluid pressure
and a void volume in the tool to apply force to a piston.
[0031] The dump bailer of FIG. 1 comprises a tool body 10 that can
be connected to a conveyance system (not shown) such as a wireline
cable, coiled tubing or drill pipe, and lowered into a well. The
tool body comprises a lower section defining a chamber 12 for
containing the fluid to be deposited in the well, and an upper
section 14 comprising an actuating mechanism that will be discussed
in more detail below. An outlet 16 is formed at the lower end of
the chamber 12 and is held normally closed by a spring loaded
relief valve 18 or other means such as a shear pin. A swabbing
piston 20 is mounted in the chamber so as to be slideable along the
chamber to drive any fluid contained therein through the outlet
16.
[0032] A sliding seal 22 is formed on the inner wall of the tool
body 10 and defines the top of the chamber 12 and the bottom of the
upper section 14.
[0033] A vent 24 is provided in the tool body 10 below the sliding
seal 22 and above the swabbing piston 20 so that there is pressure
communication between this space and the ambient pressure
surrounding the bailer.
[0034] The actuating mechanism in the upper section 14 comprises a
two-stage piston that is mechanically connected to the swabbing
piston 20. A first stage piston 26 is mounted so as to be slideable
inside the upper section 14. The first stage piston 26 has a head
end 28 that seals against the inner wall of the tool body 10, and a
lower end 30 that is reduced in diameter with respect to the head
end and defines a cylinder 32. The lower end 30 projects through
the sliding seal 22. A second stage piston 34 is mounted slideably
in the cylinder 32 and is connected to the swabbing piston 20 by
means of a connecting rod 36.
[0035] The space around the lower end 30 and delimited by the head
end 28 and the sliding seal 22 defines a reservoir 38 for a working
fluid. A passageway 40 connects the reservoir 38 to the upper end
of the cylinder 32. A valve 42 is provided in the passageway
40.
[0036] A further vent 44 is provided in the tool body 10 above the
head end 28 so that there is also pressure communication between
this space and the ambient pressure surrounding the bailer.
[0037] Alternatively the valve 42 can be positioned at the point
where the vent 44 is described above, and the passageway 40 will
remain as an open channel.
[0038] The space in the cylinder below the second stage piston 34
is not filled with working fluid, but contains either air or
another gas at or near atmospheric pressure, or, in an alternative
can be completely or partially evacuated.
[0039] As will be appreciated, pressure communication through the
vents 24, 44 means that the difference in areas at 22 and 26, on
which ambient pressure is acting, causes the working fluid within
reservoir 38 to be higher than the ambient pressure around the
tool. At a downhole location, this will be substantially above
atmospheric pressure. With the second stage piston 34 at the top of
the cylinder 32 and with the valve 42 closed, the second stage
piston 34 moves little, if at all, to adopt an equilibrium position
in which the pressure above the second stage piston 34 is the same
as that below it. As all pressures in the various sections are
balanced and there is no way for the different pressure to equalize
(the valve 42 being closed), the swabbing piston 20 does not
move.
[0040] When it is desired to evacuate the chamber 12, the valve 42
is opened. This allows working fluid from the reservoir 38 at
ambient pressure to enter the cylinder above the second stage
piston 34. Since this is a substantially higher pressure than is
found below the second stage piston 34, it is driven downwards,
pushing the swabbing piston along the chamber 13. The pressure
exerted on the fluid in the chamber 12 by the swabbing piston 20
overcomes the force of the spring in the relief valve 18 and the
fluids are deposited in the well.
[0041] As fluid passes from the reservoir 38 into the cylinder 32,
the first stage piston 26 advances along the upper section 14 to
accommodate the reduction in volume of fluid in the reservoir while
maintaining ambient pressure. This will continue until either the
second stage piston 34 reaches the bottom of the cylinder 32, the
swabbing piston 20 reaches the bottom of the chamber 12 (or some
other such mechanical stop point is reached), or until a pressure
equilibrium between the fluid above the second stage piston 34 and
the gas below it is reached.
[0042] FIG. 2 shows a variant of the embodiment of FIG. 1. The same
numbers have been used for corresponding parts. In this case, the
vent in the upper section 14 (44 in FIG. 1), is replaced by a gas
reservoir 50 and a valve 52. The gas in the reservoir is held at a
pressure higher than the ambient pressure of the well at the depth
of use. In use, both valves 42 and 52 are opened and operation
continues as described previously. The use of a pressurized gas
allows a higher driving pressure to be applied where the operation
is at relatively shallow depth such that the pressure differences
are low, or where an extra `boost` is needed to overcome static
friction, or some mechanical blockage.
[0043] FIG. 3 shows another variant of the embodiment of FIG. 1. In
this case, the outlet 16 is provided with an end fitting 54 having
an outlet passage 56 terminating in an exit port 58 that directs
flow from a side part of the end fitting 54. This particular
embodiment of the invention can be useful where the chamber 12 is
filled with acids and chemicals suitable for de-scaling and
cleaning operations within the wellbore. The basic operating
principle is the same as described above to generate the force to
displace the contents of the bailer tube. The exit port 58 can be
configured to have a fixed single or multiple exit orifice which
may be oriented to a particular azimuth within the well bore using
a muleshoe or other mechanical device (typically used within well
completions such as are used to deploy or retrieve gas-lift valves
from side pocket tools) to direct a pressure stream or jet of
cleaning agent from within the apparatus during the displacement
stroke of the ram. The tool could then be vertically oscillated
from the well surface to direct the stream as required over a
longitudinal section of the well trajectory.
[0044] With reference to FIG. 4, another embodiment of the
apparatus used for clean up purposes has an end fitting 60 with
multiple exit jets 62 arranged equally around its periphery to
direct pressurized streams or jets of cleaning agent around an
axial section of the wellbore. The end fitting 60 also be made to
freely rotate around the longitudinal axis of the apparatus using
the pressure and flow of displaced fluid from the tube as a driving
mechanism whilst the hydraulic ram is displacing the contents. This
arrangement could be used to clean a landing nipple profile or seal
area of a wellbore or tubing completion.
[0045] FIGS. 5 and 6 show another embodiment of the invention that
uses a supply of pressurized gas as the principal driving force. In
this case, the dump bailer comprises a tool body 70 that defines a
simple chamber 72 running along it whole length. The swabbing
piston 74 is able to slide along the whole length of the chamber
72. The swabbing piston 74 has an extended piston body 76 extending
from its rear surface to project through a sliding seal 78 at the
top of the chamber 72. The piston body 76 includes a reservoir of
pressurized gas (e.g. nitrogen) 80 and a passage 82 connecting the
reservoir 80 to an outlet disposed in the chamber 72 just above the
swabbing piston 74. A valve 84 is provided in the passage 82. In
use, the valve 84 is operated to allow pressurized gas to enter the
chamber 72 above the swabbing piston 74 which is forced down the
chamber 72 expelling any fluids through an outlet 86. As the
swabbing piston 74 advances, the piston body is drawn through the
sliding seal 78 until the swabbing piston 74 reaches the bottom of
the chamber 72 (FIG. 6).
[0046] A trigger section that can be used with the present
invention that essentially corresponds to a slickline firing head
of the type currently used for slickline explosive applications or
to trigger cutters and set packers and plugs. The trigger is
operated by a coded sequence of tension pulses on the slickline
wire. This coded sequence is converted to pressure pulses by a
strain sensor in the tool. This unique combination of pulses
creates the special signature required to communicate with the
firing head, or in this case with the dump bailer actuator.
[0047] A pressure transducer in the tool detects a command from the
surface (pull on the slick line). Two separate processors in the
controller module are required to independently verify the unique
command. In addition to the safety of the unique command signature
of the pressure pulses, the tool must be enabled by a preset
hydrostatic pressure, followed by an arming command sent from the
surface, before it will accept a firing command.
[0048] The trigger works by interpreting changes in downhole
pressure as instructions to perform specific operations during a
job. Pressure changes detected by a pressure gauge result from two
sources: deviations in ambient hydrostatic pressure (i.e. depth in
the well) and changes in line tension, which are translated into
pressure changes by the strain head. Completion of the firing
sequence requires suitable signals from both sources. The tool will
not fire unless it reaches a preset minimum pressure specified by
the operator. In addition, jerking on the slickline causes tension
changes detectable by the pressure transducer through the action of
the strain head. The signal produced by the jerk has unique
characteristics that can be recognized. Detection of this signal is
a slickline trigger event. The tool detects fire commands by
searching for a predefined sequence of trigger events with specific
time spacing.
[0049] Each event has an associated type, reference pressure and
reference time. These events, each with its own reference time and
pressure, are used to locate command sequences. The tool typically
takes a pressure measurement every 200 ms for use in locating these
events. Each sample is used for command analysis and saved in
memory.
[0050] The trigger section of the tool (refer to FIG. 7) comprises
a cylindrical tube housing 90, upper 92 and lower 94 connectors
which allow the trigger to be mounted concentrically to both the
slickline trigger and telescopic ram/actuator section of the tool.
Contained within the housing is an interface electronics assembly
96 which will obtain and interpret electrical signals from the
trigger tool at the appropriate time and operate an electric motor
or other electro-mechanical actuator 98. The motor or
electro-mechanical actuator will in turn operate an output shaft or
rod 100 to operate the valves 42, 52, 84 of FIGS. 1, 2, 5 and
6.
[0051] Alternatively the tool may be triggered via electric line
with a direct or indirect electrical connection to the surface, or
by a built-in timer which is powered by an internal battery and
where the delay is set at the surface.
[0052] Further, those skilled in the art should appreciate that the
parameters and configurations described herein are exemplary and
that actual parameters and/or configurations will depend on the
specific application in which the systems and techniques of the
invention are used. Those skilled in the art should also recognize
or be able to ascertain, using no more than routine
experimentation, equivalents to the specific embodiments of the
invention. It is therefore to be understood that the embodiments
described herein are presented by way of example only and that,
within the scope of the appended claims and equivalents thereto;
the invention may be practiced otherwise than as specifically
described.
[0053] Moreover, it should also be appreciated that the invention
is directed to each feature, system, subsystem, or technique
described herein and any combination of two or more features,
systems, subsystems, or techniques described herein and any
combination of two or more features, systems, subsystems, and/or
methods, if such features, systems, subsystems, and techniques are
not mutually inconsistent, is considered to be within the scope of
the invention as embodied in the claims. Further, acts, elements,
and features discussed only in connection with one embodiment are
not intended to be excluded from a similar role in other
embodiments. Rather, the systems and methods of the present
disclosure are susceptible to various modifications, variations
and/or enhancements without departing from the spirit or scope of
the present disclosure. Accordingly, the present disclosure
expressly encompasses all such modifications, variations and
enhancements within its scope.
* * * * *