U.S. patent application number 11/176091 was filed with the patent office on 2007-01-11 for apparatus and methods for activating a downhole tool.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Kerry L. Sanderlin.
Application Number | 20070007016 11/176091 |
Document ID | / |
Family ID | 37617255 |
Filed Date | 2007-01-11 |
United States Patent
Application |
20070007016 |
Kind Code |
A1 |
Sanderlin; Kerry L. |
January 11, 2007 |
Apparatus and methods for activating a downhole tool
Abstract
An apparatus for performing a downhole operation in a wellbore
comprises a tool string deployed on a slickline into the wellbore,
where the tool string comprises a controller and a tool. A motion
detector is disposed in the controller and senses motion of the
tool string and generates a first signal in response thereto. A
device disposed in the controller detects a downhole parameter of
interest and generates a second signal in response thereto. A
processor in the controller acts according to programmed
instructions to activate the tool when the first signal is below a
first preset threshold for at least a preset time interval, and the
second signal exceeds a second preset threshold. A method of using
the apparatus is also provided.
Inventors: |
Sanderlin; Kerry L.; (Katy,
TX) |
Correspondence
Address: |
MADAN, MOSSMAN & SRIRAM, P.C.
2603 AUGUSTA
SUITE 700
HOUSTON
TX
77057
US
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
37617255 |
Appl. No.: |
11/176091 |
Filed: |
July 7, 2005 |
Current U.S.
Class: |
166/381 |
Current CPC
Class: |
E21B 47/00 20130101 |
Class at
Publication: |
166/381 |
International
Class: |
E21B 19/00 20060101
E21B019/00 |
Claims
1. An apparatus for performing a downhole operation in a wellbore,
comprising: a. a tool string deployed on a slickline into the
wellbore, the tool string comprising a controller and a tool; b. a
motion detector disposed in the controller sensing motion of the
tool string and generating a first signal in response thereto; c. a
device disposed in the controller detecting a downhole parameter of
interest and generating a second signal in response thereto; d. a
processor in the controller acting according to programmed
instructions to activate the tool when the first signal is below a
first preset threshold for at least a preset time interval and the
second signal exceeds a second preset threshold.
2. The apparatus of claim 1, wherein the motion detector is chosen
from the group consisting of: an accelerometer and a noise
sensor.
3. The apparatus of claim 1, wherein the device is chosen from the
group consisting of: a pressure sensor, a temperature sensor, and a
downhole clock.
4. The apparatus of claim 1, wherein the second preset threshold is
chosen from the group consisting of: a fluid pressure, a fluid
temperature, and a deployed time interval.
5. The apparatus of claim 1, wherein the controller comprises: a.
the processor having a memory capable of storing programmed
instructions; and b. a downhole clock.
6. The apparatus of claim 1, wherein the tool is chosen from the
group consisting of: a logging tool, a perforating gun, a packer,
and a flow control valve.
7. The apparatus of claim 1, wherein the tool comprises a plurality
of tools.
8. A method of activating a downhole tool in a wellbore,
comprising: a. deploying a tool string on a slickline into the
wellbore; b. holding the tool string substantially motionless for
at least a preset time interval; c. detecting that the tool string
is substantially motionless for at least the preset time interval;
d. determining that a downhole detected parameter of interest
exceeds a second preset threshold; and e. activating a tool in the
tool string when both step c. and d. are met.
9. The method of claim 8, wherein, the tool string comprises a
controller and a tool.
10. The method of claim 8, wherein the step of detecting that the
tool string is substantially motionless comprises determining that
a signal from a motion detector is below a first preset threshold
at least the preset time interval.
11. The method of claim 10, wherein the motion detector is chosen
from the group consisting of: an accelerometer and a noise
sensor.
12. The method of claim 8, wherein the downhole detected parameter
of interest is chosen from the group consisting of: a downhole
fluid pressure, a downhole fluid temperature, and a deployed time
interval.
13. The method of claim 8, wherein the tool is chosen from the
group consisting of: a logging tool, a perforating gun, a packer,
and a flow control valve.
14. The method of claim 8, wherein the tool comprises a plurality
of tools.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention pertains to oil field operations and
more particularly to an apparatus and methods for activating a
downhole tool.
[0003] 2. Related Prior Art
[0004] A number of operations may be performed in a common oil
wellbore by running tools in on a line that is controlled from the
surface. In many cases, hardware for logging, perforating, and flow
control may be run into the hole on slickline. Slickline commonly
comprises a thin, nonelectric cable used for selective placement
and retrieval of wellbore hardware. Downhole valves and sleeves can
also be adjusted using slickline tools. In many such tools, such as
battery powered logging tools, it is desirable to control the
turn-on and operation of the tools from the surface. Such tools may
contain, for example, caliper arms that contact the borehole wall
enable logging tool sensor contact with the formation surrounding
the wellbore. These arms must be in a collapsed state during
transit to prevent the tool from hanging up on the way into the
wellbore. In other instances, such as with perforating guns, it is
desirable to prevent their arming and possible firing until they
are safely downhole.
[0005] Without electrical communication to the surface, prior art
tools have used several techniques for actuating such tools
downhole. These include raising the bottomhole pressure by a
predetermined amount such that a pressure sensor in the downhole
tool senses the increased pressure as a signal to actuate. The
pressure increase may be in the form of a static increase or in the
form of a sequence of pressure pulses that are detected downhole.
However, the bottomhole pressure in a well is commonly balanced to
hold back formation fluid ingress to the wellbore while not
exceeding the fracture pressure of the formation surrounding the
wellbore. The increased pressure signal, in many instances, may be
sufficient to cause fractures in the formation. Even if the
formation does not fracture, the increase pressure in the wellbore
may be sufficient to force wellbore fluids to invade the formation
and cause errors in subsequent logging operations.
[0006] In another prior art downhole tool, a preset time interval
is set in a timer in the tool at the surface such that the tool is
then deployed to the desired location before the preset time
interval has been exceeded. When the preset time interval is
exceeded, the tool is activated. Problems in deploying the tool may
occur that causes the preset time interval to be exceeded before
the tool is properly deployed. Activation of the tool may cause the
tool to be stuck in the hole, or cause damage to the wellbore.
[0007] There is a demonstrated need for a reliable, safe method of
activating slickline tools downhole. The present invention
addresses these and other shortcomings of the prior art described
above.
SUMMARY OF THE INVENTION
[0008] In one aspect of the present invention, an apparatus for
performing a downhole operation in a wellbore comprises a tool
string deployed on a slickline into the wellbore, where the tool
string comprises a controller and a tool. A motion detector is
disposed in the controller and senses motion of the tool string and
generates a first signal in response thereto. A device disposed in
the controller detects a downhole parameter of interest and
generates a second signal in response thereto. A processor in the
controller acts according to programmed instructions to activate
the tool when the first signal is below a first preset threshold
for at least a preset time interval, and the second signal exceeds
a second preset threshold.
[0009] In another aspect, a method of activating a downhole tool in
a wellbore comprises deploying a tool string on a slickline into
the wellbore. The tool string is held substantially motionless for
at least a preset time interval at a location in the wellbore. A
motion detector determines that the tool string is substantially
motionless for at least the preset time interval. It is determined
that a downhole detected parameter of interest exceeds a second
preset threshold. A tool is activated in the tool string when both
the tool is substantially motionless for at least a preset time
interval, and a downhole detected parameter of interest exceeds a
second preset threshold.
[0010] These and other aspects of the present invention are more
clearly described in the drawings and specification that
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For detailed understanding of the present invention,
references should be made to the following detailed description of
the preferred embodiment, taken in conjunction with the
accompanying drawings, in which like elements have been given like
numerals and wherein:
[0012] FIG. 1 is a sketch of an exemplary tool string deployed on a
slickline;
[0013] FIG. 2. is a block diagram of the tool string; and
[0014] FIG. 3 is a block diagram depicting an example of the
operation of one embodiment of the present invention.
DESCRIPTION
[0015] Referring initially to FIG. 1, there is shown an exemplary
downhole tool string 11 comprising downhole controller 10 and tool
18. Tool string 11 is supported by slickline 12. Slickline 12
extends from rig 14 at the surface 16. Slickline 12 is deployed
from winch 29 around one or more sheave wheels 26, supported from
rig 14, and down borehole 20. Surface controller 28 provides
suitable power and controls associated with winch 29 for
controlling the deployment of the slickline into borehole 20.
Alternatively, winch 29 may be separately controlled and surface
controller 28 may be a portable computer, such as a personal
computer, having appropriate interfaces circuitry to communicate,
at the surface, with downhole controller 10. Tool string 11 is
deployed adjacent production zone 22 located, for example, near the
bottom 24 of borehole 20, also called a wellbore. Borehole 20
commonly has a fluid 13 disposed therein which may be a drilling
fluid (also called drilling mud), a production control fluid,
and/or a produced fluid from production zone 22. The produced fluid
may be water, hydrocarbon liquid, gas, or any combination of the
above.
[0016] Tool 18 may include multiple downhole tools including but
not limited to: a logging tool, a perforating gun, a packer, a flow
control valve, and/or any other device suitable for running on
slickline 12 and performing downhole operations. The logging tool
includes, but is not limited to: an acoustic tool, a density tool,
a neutron tool, an induction resistivity tool, an NMR tool, and a
gamma ray tool. The logging tool may be a single tool or any
combination of such tools, as described above. The downhole tools
may be exposed to fluid pressures up to 30,000 psi and temperatures
up to 500.degree. F. The downhole fluid may be brine, water based
drilling fluid, oil base drilling fluid and/or fluids that may
contain hydrogen sulfide, carbon dioxide, methane, and other
deleterious compounds.
[0017] FIG. 2 is a block diagram of an exemplary embodiment of
downhole controller 10 of the present invention. Downhole
controller 10 includes processor 31 having sufficient memory
therein for storing programmed instructions for operating downhole
controller 10 and for storing preset sensor thresholds for use in
the present invention. Circuits 32 interface processor 31 with
clock 35, motion sensor 33, pressure sensor 34, and temperature
sensor 39 and with tool 18. Clock 35 is a crystal oscillator and is
used to measure elapsed time from a start signal initiated by
surface controller 37 before tool string 11 is deployed in wellbore
20. Clock 35 may be adapted to provide real-time. Motion sensor 33,
pressure sensor 34, and temperature sensor 39 are also disposed in
controller 10. Motion sensor 33 is used to determine when tool
string 11 is motionless. Clock 35 also contains a timer for
determining the length of time that the tool is held substantially
motionless. In one embodiment, accelerometers 60 are mounted in
controller 10 and used to detect motion of tool string 11. Lack of
motion is determined when a signal from the accelerometers is below
a preset threshold level. It should be noted that the threshold
level is somewhat application dependent and is field settable. For
example, in a well with fluid flowing past the tool, there will be
flow turbulence affecting the accelerometer signal level even when
slickline 12 is being held steady at the surface. In a non-flowing
well, the accelerometer threshold may be set at a lower level.
Alternatively, motion may be detected by a noise sensor 61 that
detects the noise associated with the contact of tool string 11
with the wall of wellbore 20 and the flow noise associated with the
movement of tool string 11 through either a static or flowing fluid
in wellbore 20. Noise sensor 61 may include a piezoelectric crystal
and/or a piezoelectric film mounted on controller 10 such that
noise sensor 61 is exposed to fluid 13 in wellbore 20. Power source
36 provides power to operate controller 10 and its associated
devices. In one embodiment, power source 36 includes batteries (not
separately shown) suitable for downhole use. Such batteries are
commercially available and are not described here further.
Controller 10 is electrically and mechanically coupled to tool 18
using techniques known in the art. Power source 36 contains
sufficient power to operate tool 18. Alternatively, tool 18
contains its own separate power source.
[0018] Pressure sensor 34 and temperature sensor 39 are mounted in
controller 10 such that they are able to measure the steady-state
downhole pressure and temperature of fluid 13 in wellbore 20. Such
sensors are commercially available and will not be described
here.
[0019] Processor 31 contains programmed instructions for
determining when to activate tool 18. FIG. 3 shows an operational
flow chart of an exemplary operation of the present invention.
Depending on the particular desired downhole location of interest
and the nature of the downhole operation, in step 40, a motion
sensor threshold and a length of time that the tool must be
motionless are programmed into processor 31 at the surface and
prior to deployment into wellbore 20, using a connection to surface
processor 28. At least one additional parameter threshold is also
downloaded by the operator into processor 31, prior to deployment,
using a connection to surface processor 28.
[0020] Tool string 11 is deployed into wellbore 20 in step 45.
Motion detection is continuous during the entire downhole
operation. The tool is stopped and held substantially motionless in
step 46. In step 47, the motion detection sensor signal falls below
the preset threshold level, and clock 35 begins a separate timer to
determine the length of time that the tool is motionless and
compare the measured time interval to the preset motionless
threshold interval. When the motionless time period exceeds the
preset motionless threshold interval, controller 10 proceeds to
sense the additional parameter of interest and compare the
measurement to its preset threshold value in step 48. The
additional parameter may be downhole pressure, downhole
temperature, and/or a total deployment time interval. At least one
additional parameter is used. However any number or combination of
the additional parameters may be used. If all of the criteria are
met, then downhole tool 18 is activated in step 49.
[0021] In one example, the tool may be programmed to activate when
all of the following conditions are met: [0022] the motion detector
signal remains below the motion threshold for 5 minutes; and [0023]
the bottomhole pressure is at least 5000 psi; and [0024] the
bottomhole temperature is at least 80C; and [0025] the tool
deployment time is at least 90 minutes. As seen in this example,
the tool may be safely handled at the surface, and activation
downhole does not require an increase in bottomhole pressure.
[0026] While described above as separate devices, in another
embodiment, controller 10 may be included as part of tool 18.
[0027] While there has been illustrated and described a particular
embodiment of the present invention, it will be appreciated that
numerous changes and modifications will occur to those skilled in
the art, and it is intended in the appended claims to cover all
those changes and modifications, wherein the word "comprising", as
used throughout the claims, is to be interpreted to mean "including
but not limited to."
* * * * *