Note: Descriptions are shown in the official language in which they were submitted.
CA 02379451 2004-11-08
Field of the Invention
This invention relates to generally to wells used in the production of fluids
such as oil and gas. More specifically, this invention relates to a method and
system for performing various operations and for improving production in
wells.
Background of the Invention
Different operations are performed during the drilling and completion of a
subterranean well, and also during the production of fluids from subterranean
formations via the completed well. For example, different downhole operations
are
typically performed at some depth within the well, but are controlled at the
surface.
A perforating process is one type of downhole operation that is used to
perforate a well casing. A conventional perforating process is performed by
placing a perforating tool (i.e., perforating gun) in a well casing, along a
section of
the casing proximate to a geological formation of interest. The perforating
tool
carries shaped charges that are detonated using a signal transmitted from the
surface to the charges. Detonation of the charges creates openings in the
casing
and concrete around the casing, which are then used to establish fluid
communication between the geological formation, and the inside diameter of the
casing.
Another example of a downhole operation is the setting of packers within
the well casing to isolate a particular section of the well or a particular
geological
formation. In this case, a packer can be placed within the well casing at a
desired
depth, and then set by a setting tool actuated from the surface. Other
exemplary
downhole operations include the placement of logging tools at a particular
geological formation or depth within the well casing, and the placement of
bridge
plugs, casing patches, tubulars, and associated tools in the well casing.
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One critical aspect of any downhole operation involves
ascertaining the depth in the well where the operation is to be
performed. The depth is typically ascertained using well logs. A
conventional well log includes continuous readings from a logging
instrument, and an axis which represents the well depths at
which the readings were obtained. The instrument readings
measure rock characteristics such as natural gamma ray
radiation, electrical resistivity, density and acoustic properties.
Using these rock characteristics geological formations of
1o interest within the well, such as oil and gas bearing formations,
can be identified. The well is initially logged "open hole" which
becomes the bench mark for all future fogs. After the well is
cased, a cased hole log is then prepared and correlated, or "tied
in", to the open hole log.
25 Using the logs and a positioning mechanism, such as a wire
line or coiled tubing, coupled to an odometer, a tool can be placed
at a desired depth within the well, and then actuated as required
to perform the downhole operation. One problem with
conventional logging and positioning techniques is that it is
2o difficult to accurately identify the depth of the tool, and to
correlate the depth to the open hole logs.
Figure 1 illustrates a prior art perforating process being
performed in an oil and gas well 10. The well 10 includes a well
bore 12, and a casing 14 within the well bore 12 surrounded by
25 concrete 16. The well 10 extends from an earthen surface 18
through geological formations within the earth, which are
represented as Zones A, B and C. The casing 14 is formed by
tubular elements, such as pipe or tubing sections, connected to
one another by collars 20. In this example the tubular elements
3o that form the casing 14 are about 40 feet long so that the casing
collars 20 are forty feet apart. However, tubular elements with
shorter lengths (e.g., twenty feet) can be interspersed with the
forty feet lengths to aid in depth determinations. Thus in Figure
1 two of the casing collars 20 are only twenty feet apart.
35 For performing the perforating operation a perforating tool
22 has been lowered into,the casing 14 on a wire line 24. A mast
26 and pulleys 28 support the wire line 24, and a wire line unit
30 controls the wire line 24. The wire line unit 30 includes a
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drive mechanism 32 that lowers the wire line 24 and the tool 22
into the well 10, and raises the wire line 24 and the tool 22 out
of the well 10 at the completion of the process. The wire line
unit 30 also includes an odometer 34 that measures the unwound
length of the wire line 24 as it is lowered into the well 10, and
equates this measurement to the depth of the tool 22 within the
well.
During formation of the well 10 an open hole log 36 was
prepared. The open hole log 36 includes various instrument
1o readings, such as gamma ray readings 38 and spontaneous
potential (SP) readings 40 which are plotted as a function of
depth in feet. For simplicity only a portion of the open hole log
36, from about 7000 feet to about 7220 feet, is illustrated.
However, in actual practice the entire well 10 from the surface
18 to the bottom of the well 10 may be logged. The open hole log
36 permits skilled artisans to ascertain the oil and gas
containing formations within the well 10 and the most productive
intervals of those formations. For example, based on the gamma
ray readings 38 and the SP readings 40 it is determined that Zone
2o A may contain oil and gas reserves. It is thus desired to
perforate the casing 14 along a section thereof proximate to Zone
A.
In addition to the open hole log 36, following casing of the
well 10, cased hole gamma ray readings 44 are made, and a casing
collar log 42 can be prepared. The casing collar log 42 is also
referred to as a PDC log (perforating depth control log). The
casing collar log 42 can be used to identify the section of the
casing 14 proximate to Zone A where the perforations are to be
made.
3o Using techniques and equipment that are known in the art,
the casing collar log 42 can be accurately correlated, or "tied in",
to the open hole log 36. However, using conventional positioning
mechanisms, such as the wire line unit 30, it may be difficult to
accurately place the perforating tool 22 at the required depth
within the well. For example, factors such as stretching,
elongation from thermal effects, sinusoidal and helical buckling,
and deformation of the wire line 24 can affect the odometer
readings, and the accuracy of the odometer readings relative to
the open hole odometer readings.
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Thus, as shown in Figure 1, the odometer readings which
indicate the depth of the perforating tool 22, may not equate to
the actual depths, as reflected in the open hole log 36 and the
casing collar log 42 . In this example, the odometer readings
s differ from the depths identified in the open hole log 36 and the
casing collar log 42 by about 40 feet. With this situation, when
the perforating toot 22 is fired, the section of casing 20
proximate to Zone A may be only partially perforated, or not
perforated at all.
so Because of these tool positioning inaccuracies, various
correlative joint logging and wire logging techniques have been
developed in the art. For example, one prior art technique uses
electronic joint sensors, and electrically conductive wire line, to
determine joint-to-joint lengths, and to correlate the odometer
15 readings of the wire line to the casing collar log. Although these
correlative joint logging and wire line logging techniques are
accurate, they are expensive and time consuming. In particular,
additional crews and surface equipment are required, and
additional wire line footage charges are incurred.
2o In addition to tool positioning inaccuracies, computational
errors also introduce inaccuracies in depth computations. For
example, a tool operator can make computational errors by
thinking one number (e.g., 7100), while the true number may be
different (e.g., 7010). Also, the tool operator may position the
25 tool. by compensating a desired amount in the uphole direction,
when in reality the downhole direction should have been used.
These computational errors are compounded by fatigue, the
weather, and communication problems at the well site.
It would be desirable to obtain accurate depth readings for
3o downhole tools without the necessity for complicated and
expensive correlative joint logging and wire logging techniques.
In addition, it would be desirable to control down hole operations
and processes without having to rely on inaccurate depth readings
contaminated by computational errors. The present invention is
35 directed to an improved method and system for performing
operations and processes in wells, in which the depths of down
hole tools are accurately ascertained and used to control the
operations and processes.
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Another limitation of conventional downhole operations that
are dependent on depth measurements, is that downhole tools
must first be positioned in the well, and then actuated from the
surface. This requires additional time and effort from well
crews. In addition, surface actuation introduces additional
equipment and variables to the operations. It would be
advantageous to be able to control downhole operations without
the requirement of surface actuation of the downhole tools. With
the present invention actuation of downhole tools can be
1o performed in the well at the required depth.
Summary of the Invention
In accordance with the present invention a method and a
system for performing various operations in wells, and for
s5 improving production in wells, are provided. Exemplary
operations that can be performed using the method include
perforating processes, packer setting processes, bridge plug
setting processes, logging processes, inspection processes,
chemical treating processes, casing patch processes, jet cutting
2o processes and cleaning processes. Each of these processes, when
performed in a well according to the method, improves the well
and improves production from the well.
In an illustrative embodiment the method is used to perform
a perforating process in an oil or gas production well. The well
25 includes a well bore, and a well casing, extending from an earthen
or subsea surface into various geological zones within the earth.
The well casing includes lengths of pipe or tubing joined together
by casing collars.
The method includes the initial step of providing
3o identification devices at spaced intervals along the length of the
well casing. The identification devices can comprise active or
o passive radio identification devices installed in each casing
collar of the well casing. Each radio identification device is
uniquely identified, and its depth, or location, within the well is
35 accurately ascertained by correlation to well logs. Similarly,
each casing collar is uniquely identified by the radio
identification device contained therein, and a record of the well
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including the depth of each casing collar and identification device
is established.
The method also includes the step of providing a reader
device, and a transport mechanism for moving the reader device
through the well casing proximate to the identification devices.
In the illustrative embodiment the reader device comprises a
radio frequency transmitter and receiver configured to provide
transmission signals for reception by the identification devices.
The identification devices are configured to receive the
Zo transmission signals, and to transmit response signals back to
the reader device. The transport mechanism for the reader device
can comprise a wire line, tubulars, coil tubing, a robotic
mechanism, a fluid transport mechanism such as a pump or a
blower, a free fall arrangement, or a controlled fall arrangement
such as a parachute.
In addition to transmitting and receiving signals from the
identification devices, the reader device is also configured to
transmit control signals for controlling a process tool, as a
function of the response signals from the identification devices.
2o For example, ~ the reader device can control a perforating tool
configured to perforate the well casing. Specifically, the reader
device and the perforating tool can be transported together
through the well casing past the identification devices. In
addition, the reader device can be programmed to transmit the
control signal to detonate the perforating tool, upon reception of
a response signal from an identification device located at a
predetermined depth or~ location within the well. Stated
differently, the reader device can be programmed to control the
perforating tool responsive to locating a specific identification
3 o device.
As other examples, the reader device can be configured to
control setting tools for packers, bridge plugs or casing patches,
to control instrument readings from logging tools, and to control
jet cutters and similar tools. With the method of the invention
the true depth of the process tool can be ascertained in real time
by the reader device using response signals from the
identification devices. Accordingly, there is no need to ascertain
the depth of the tool using an odometer, and expensive wire
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lagging techniques. In addition, operator computational errors are
reduced because true depth readings can be provided without the
requirement of additional computations. Further, for some
processes, there is no need to transmit signals to the surface, as
the reader device can be programmed to control the process in
situ within the well.
However, it is to be understood that the method of the
invention can also be practiced by transmission of the control
signals from the reader device to a controller or computer at the
surface, and control of the process tool by the controller or
computer. In addition, control of the process tool can be
performed dynamically as the process tool moves through the
well with the reader device, or statically by stopping the process
tool at a required depth. Further, the method of the invention can
be used to control a multi stage process, or to control a tool
configured to perform multiple processes. For example, a
combination packer setting and perforating tool can be configured
to perform packer setting and perforating processes, as a
function of true depth readings obtained using the method of the
2o invention.
In the illustrative embodiment the system includes the
identification devices installed in casing collars at spaced
intervals along the well casing. The identification devices
include a programmable element, such as a transceiver chip for
receiving and storing identification information, such as casing
collar and depth designations. Each identification device can be
configured as a passive device, an active device having an
antenna, or a passive device which can be placed in an active
state by transmission of signals through well fluids.
3o The system also includes the reader device and the process
tool configured for transport through the well casing. In addition
to the transmitter and receiver, the reader device includes one or
more programmable memory devices, such as semiconductor chips
configured to receive and store information. The reader device
also includes a power source such as a power line to the surface,
or a battery. In addition, the reader device includes a telemetry
circuit for transmitting the control signals, which can be used to
control the process tool, and to provide depth and other
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information to operators and equipment at the surface. The
system can also include a computer configured to receive and
process the control signals, and to provide and store information
in visual or other form for well operators and equipment. Further,
the system can include a controller configured to process the
control signals for controlling the process tool and various
process equipment. The controller can be located at the surface,
or on the process tool, to provide a self contained system. Also,
the system can be transported to a wel( site in the form of a kit,
1o and then assembled at the well site.
Brief Description of the Drawinas
Figure 1 is a schematic diagram of a prior art downhole
operation being performed using well logs and odometer readings
from a tool positioning mechanism;
Figure 2 is a flow diagram illustrating steps in the method
of the invention for controlling a perforating process in a well;
Figures 3A and 3B are schematic cross sectional views
illustrating a system constructed in accordance with the
2o invention for performing the perforating process;
Figure 3C is an enlarged portion of Figure 3B, taken along
section line 3C, illustrating a perforating tool of the system;
Figure 3D is an enlarged portion of Figure 3A, taken along
section line 3D, illustrating a reader device and an identification
device of the system;
Figure 3E is an enlarged cross sectional view taken along
section line 3E of Figure 3D illustrating a portion of the reader
device;
Figure 3F is a side elevation view of an alternate
3o embodiment active reader device and threaded mounting device;
Figure 4A is an electrical schematic for the system;
Figure 4B is a view of a computer screen for a computer of
the system;
Figures 5A and 5B are schematic views illustrating
exemplary spacer elements for spacing the reader device of the
system from the perforating tool of the system;
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Figures 6A-6D are schematic cross sectional views
illustrating various alternate embodiment transport mechanisms
for the system;
Figures 7A and 7B are schematic cross sectional views
illustrating an alternate embodiment system constructed in
accordance with the invention for performing a packer setting
process in a well;
Figure 7C is an enlarged portion of Figure 7A taken along
section line 7C illustrating a threaded connection of a tubing
1o string of the alternate embodiment system; and
Figure 8A-8C are schematic cross sectional views
illustrating an alternate embodiment mufti stage method and
system of the invention for performing a packer setting and a
perforating processes in combination.
Detailed Description of the Preferred Embodiment
Referring to Figure 2, broad steps in a method for
controlling an operation or process in a subterranean well in
accordance with the invention are illustrated. The method,
2o broadly stated, includes the steps of:
A. Providing a process tool.
B. Providing a reader device in signal communication with
the process tool.
C. Providing a transport mechanism for the process tool and
the reader device.
D. Providing spaced identification devices in a well casing
readable by the reader device.
E. Uniquely identifying each identification device and
determining its depth, or location, in the well using well logs.
3o F. Programming the reader device to transmit a control
signal to the process tool upon reception of a response signal
from a selected identification device.
G. Transporting the process tool and the reader , device
through the well casing.
H. Reading the identification devices using the reader
device.
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I. Transmitting the control signal to the process tool upon
reception of the signal from the selected identification device to
actuate the process tool at a selected depth.
Referring to Figures 3A-3D, a system 50 constructed in
s accordance with the invention is illustrated. The system 50 is
installed in a subterranean well 52, such as an oil and gas
production well. In this embodiment the system 50 is configured
to perform a perforating process in the well 52. The perforating
process performed in accordance with the invention provides an
1o improved well 52, and improves production from the well 52.
The well 52 includes a well bore 54, and a well casing 56
within the well bore 54 surrounded by concrete 56. The well 52
extends from an earthen surface 60 through geological formations
within the earth, which are represented as Zones E, F and G. The
15 earthen surface 60 can be the ground, or alternately a structure,
such as an oil platform located above water. In the illustrative
embodiment, the well 52 extends generally vertically from the
surface 60 through Zones E, F, and G. However, it is to be
understood that the method can also be practiced on inclined
2o wells, and on horizontal wells.
The well casing 56 comprises a plurality of tubular
elements 62, such as lengths of metal pipe or tubing, connected to
one another by collars 64. The casing 56 includes an inside
diameter adapted to transmit fluids into, or out of, the well 52,
25 and an outside diameter surrounded by the concrete 58. The
collars 64 can comprise couplings having female threads adapted
for mating engagement with male threads on the tubular elements
62. Alternately, the collars 64 can comprise weldable couplings
adapted for welding to the tubular elements 62.
3o Also in the illustrative embodiment the casing 56 is
illustrated as having the same outside diameter and inside
diameter throughout its length. However, it is to be understood
that the casing 56 can vary in size at different depths in the well
52, as would occur by assembling tubulars with different
35 diameters. For example, the casing 56 can comprise a
telescoping structure in which the size thereof decreases with
increasing depth.
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Based on an open hole well log (36-Figure 1 ), or other
information, it is determined that Zone F of the well 52 may
contain oil and gas. It is thus desired to perforate the casing 56
proximate to Zone F to establish fluid communication between
Zone F, and the inside diameter of the well casing 56.
For performing the perforating process, the system 50
includes a perforating tool 68, and a reader device 70 in signal
communication with the perforating tool 68. The system 50 also
includes a plurality of identification devices 72 (Figure 3D)
so attached to the collars 64 on the casing 56, and readable by the
reader device 70. In addition, the system 50 includes a transport
mechanism 66W for transporting the perforating tool 68 and the
reader device 70 through the well casing 56 to Zone F. If desired,
the system 50 can be transported to the well 52 as a kit, and then
15 assembled at the well 52.
As shown in Figure 3C, the perforating tool 68 includes a
detonator 74 (illustrated schematically) and a detonator cord 76
in signal communication with the detonator 74. The detonator 74
can comprise a commercially available impact or electrical
2o detonator configured for actuation by a signal from the reader
device 70. Similarly, the detonator cord 76 can comprise a
commercially available component. The detonator 74 and the
detonator cord 76 are configured to generate and apply a
threshold detonating energy to initiate a detonation sequence of
25 the perforating tool 68. In the illustrative embodiment, the
detonator 74 is located on, or within, the perforating tool 68.
As shown in Figure 3C, the perforating tool 68 also includes
one or more charge carriers 78 each of which comprises a
plurality of charge assemblies 80. The charge carriers 78 and
3o charge assemblies 80 can be similar to, or constructed from,
commercially available perforating guns. Upon detonation, each
charge assembly 80 is adapted to blast an opening 82 through the
casing 56 and the concrete 58, and into the rock or other material
that forms Zone F.
35 As shown in Figure 3D, each collar 64 includes an
identification device 72. Each identification device 72 can be
attached to a resilient o-ring 86 placed in a groove 84 within
each collar 64.
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In the illustrative embodiment, the identification devices 72 comprise
passive radio identification devices (PRIDs). PRIDs are commercially available
and are widely used in applications such as to identify merchandise in retail
stores,
and books in libraries. The PRIDs include a circuit which is configured to
resonate
upon reception of radio frequency energy from a radio transmission of
appropriate
frequency and strength. Passive PRIDs do not require a power source, as the
energy received from the transmission signal provides the power for the PRIDs
to
transmit a reply signal during reception of the transmission signal.
The identification device 72 includes an integrated circuit chip, such as a
transceiver chip, having memory storage capabilities. The integrated circuit
chip
can be configured to receive RF signals and to encode and store data based on
the signals. During a data encoding operation each identification device 72
can
be uniquely identified such that each collar 64 is also uniquely identified.
This
identification information is indicated by the C1-C8 designations in Figures
3A and
3B. In addition, the depth of each collar 64 can be ascertained using well
logs, as
previously explained and shown in Figure 1. The depth information can then be
correlated to the identification information encoded into the identification
device
72. A record can thus be established identifying each collar 64 and its true
depth
in the well 52.
Alternately, as shown in Figure 3F, identification device 72A can be in the
form of an active device having a separate power source such as a battery. In
addition, the identification device 72A can include an antenna 89 for
transmitting
signals. Alternately, an identification device (not shown) can be configured
to
transmit signals through a well fluid or other transmission medium within the
well
52. Such an identification device is further described in U.S. Patent No.
6,333,699.
As also shown in Figure 3F, the identification device 72A can be contained
in a threaded mounting device 87. The threaded mounting device 87 can
comprise a rigid, non-conductive material such as a plastic. The threaded
mounting device 87 is configured
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to be screwed into the middle portions of the casing collar 64
(Figure 3D), and to be retained between adjacent tubular elements
of the casing 56. The threaded mounting device 87 includes a
circumferential groove 91 for the antenna 89, and a recess 93 for
the identification device 72A. If desired, the antenna 89 and the
identification device 72A can be retained in the groove 91 and the
recess 93 using an adhesive or a suitable fastener.
Referring to Figure 3E, the reader device 70 is shown in
greater detail. The reader device 70 is configured to transmit RF
1o transmission signals at a selected frequency to the identification
devices 72, and to receive RF response signals from the
identification devices 72. As such, the reader device 70 includes
a base member 77 having a transmitter 73 configured to transmit
transmission signals of a first frequency to the identification
devices 72. The reader device 70 includes a receiver 71 on the
base member 77 configured to receive signals of a second
frequency from the identification devices 72.
Preferably, the transmitter 73 is configured to provide
relatively weak transmission signals such that only an
2o identification device 72 within a close proximity (e.g., one foot)
of the reader device 70 receives the transmission signals.
Alternately, the antenna of the reader device 70 can be configured
to provide highly directional transmission signals such that the
transmission signals radiate essentially horizontally from the
reader device 70. Accordingly, the transmission signals from the
reader device 70~ are only received by a single identification
device 72 as the reader devices passes in close proximity to the
single identification device 72.
In addition to the transmitter 73 and the receiver 71, the
3o reader device 70 includes a cover 79 made of an electrically non
conductive material, such as plastic or fiberglass. The reader
device 70 also includes o-rings 75 on the base member 77 for
sealing the cover 79, and a cap member 81 attached to the base
member 77 which secures the cover 79 on the base member 77.
In addition, the reader device 70 includes spacer elements 83
formed of an electrically non-conductive material such as ferrite,
ceramic or plastic, which separate the transmitter 73 and the
receiver 71 from the base member 77. In the illustrative
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embodiment, the base member 77 i$ generally cylindrical in
shape, and the spacer elements 83 comprise donuts with a half
moon or contoured cross section.
Referring to Figure 4A, an electrical schematic for the
system 50 is illustrated. As illustrated schematically, each
identification device 72 includes a memory device 110, in the
form of a programmable integrated circuit chip, such as a
transceiver chip, configured to receive and store identification
information. As previously explained, the identification
so information can uniquely identify each casing collar 64 with an
alpha numerical, numerical or other designator. In addition, using
previously prepared well logs, the depth of each uniquely
identified casing collar 64 can be ascertained.
As also shown in Figure 4A, the reader device .70 includes
z5 the transmitter 73 for transmitting transmission signals to the
identification devices 72, and the receiver 71 for receiving the
response signals from the identification devices 72. The reader
device 70 can be powered by a suitable power source, such as a
battery, or a power supply at the surface. In addition, the reader
2o device 70 includes a memory device 112, such as one or more
integrated circuit chips, configured to receive and store
programming information.. The reader device 70 also includes a
telemetry circuit 114 configured to transmit control signals in
digital or other form, through software 116 to a controller 118,
25 or alternately to a computer 122.
As is apparent the software 116 can be included in the
controller 118, or in the computer 122. In addition, the computer
122 can comprise a portable device such as a lap top which can be
pre-programmed and transported to the well site. Also, as will
3o be further explained, the computer 122 can include a visual
display for displaying information received from the reader
device 70. The controller 118, or the computer 122, interface
with tool control circuitry 120, which is configured to control
the perforating tool 68 as required.
35 In the illustrative embodiment, the tool control circuitry
120 is in signal communication with the detonator 74 (Figure 3C)
of the perforating tool 68. The tool control circuitry 120 can be
located on the perforating tool 68, on the reader device 70, or at
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the surface. The reader device 70 is programmed to transmit
control signals to the tool control circuitry 120, as a function of
response signals received from the identification devices 72. For
example, in the perforating process illustrated in Figures 3A and
3B, coupling C4 is located proximate to the upper level, or entry
point into Zone F. Since it is desired to actuate the perforating
tool 68 while it is in Zone F, the reader device 70 can be
programmed to transmit actuation control signals through the
tool control circuitry 120 to the detonator 74 (Figure 3C), when it
1o passes coupling C4 and receives response signals from the
identification device 72 contained in coupling C4. Because
coupling C4 is uniquely identified by the identification device 72
contained therein, and the depth of coupling C4 has been
previously identified using well logs, the perforating process can
be initiated in real time, as the perforating tool 68 passes
coupling C4 and enters the section of the well casing 56
proximate to Zone F.
However, in order to insure that the detonation sequence is
initiated at the right time additional factors must be considered.
2o For example, the perforating tool 68 and reader device 70 can be
transported through the well casing 56 with a certain velocity
(V). In addition, the reader device 70 requires a certain time
period (T1 ) to transmit transmission signals to the identification
device 72 in coupling C4, and to receive response signals from the
identification device 72 in coupling C4. In addition, a certain
time period (T2) is required for transmitting signals to the tool
control circuitry 120 and to the detonator 74 (Figure 3C).
Further, the charge assemblies 80 require a certain time period
(T3) before detonation, explosion and perforation of the casing 56
occur. All of these factors can be considered in determining
which identification device 72 in which casing 64 will be used to
make the reader device 70 transmit actuation control signals
through the tool control circuitry 120 to the detonator 74 (Figure
3C).
In order to provide proper timing for the detonation
sequence, the velocity (V) of the perforating tool 68 and the
reader device 70 can be selected as required. In addition, as
shown in Figures 5A and 5B, a spacer element 88 can be used to
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space the perforating tool 68 from the reader device 70- by a
predetermined distance (D). As shown in Figure 5A, the
perforating tool 68 can be above the reader device 70 (i.e., closer
to the surface 60), or alternately as shown in Figure 5B can be
s below the reader device 70 (i.e., farther from the surface 60).
As an alternative to a dynamic detonation sequence, the
perforating tool 68 can be stopped when the required depth is
reached, and a static detonation sequence performed. For
example, the reader device 70 can be programmed to send a signal
1o for stopping the perforating tool 68 when it reaches coupling C6.
In this case, the signal from the reader device 70 can be used to
control the wire line unit 92 and stop the wire line 90. The
detonation and explosive sequence can then be initiated by signals
from the tool control circuit 120, with the perforating tool 68 in
i5 a static condition at the required depth.
As shown in Figure 4B, signals from the reader device 70
can be used to generate a visual display 124, such as a computer
screen on the computer 122, which is viewable by an operator at
the surface. The visual display 124 is titled "True Depth
2o Systems" and includes a power switch for enabling power to the
_ reader device 70 and other system components. The visual
display 124 also includes a "Depth Meter" that indicates the depth
of the reader device 70 (or the perforating tool 68) within the
well 52. The visual display 124 also includes "Alarm Indicators"
2s including a "Well Alarm Top" indicator, a "Well Alarm Bottom"
indicator, and an "Explosive Device" indicator.. The "Alarm
Indicators" are similar to stop lights with green, yellow and red
lights to indicate varying conditions.
The visual display 124 also includes "Power Indicators"
3o including a "True Depth Reader" power indicator, a "True Depth
Encoder" power indicator, and a "System Monitor" power indicator.
In addition, the visual display 124 includes various "Digital
Indicators". For example, a "Line Speed" digital indicator
indicates the speed at which the reader device 70, and the
35 perforating tool 68, are being transported through the well casing
56. An "Encoder Depth" digital indicator indicates the depth of
each identification device 72 as the reader device 70 passes by
the identification devices 72. A "True Depth" indicator indicates
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the actual depth of the reader device 70 in real time as it is
transported through the well casing 56.
The visual display 124 also includes a "TDS ID" indicator
that indicates an ID number for each identification device 72. In
addition, the visual display 124 includes a "TDS Description"
indicator that further describes each identification device 72
(e.g., location in a specific component or zone). The visual display
124 also includes a "Time" indicator that can be used as a time
drive (forward or backward) fo.r demonstration or review
1o purposes. Finally, the visual display 124 includes an "API Log"
which indicates log information, such as gamma ray or SPE
readings, from the previously .described well logs, correlated to
the "Digital Indicators" for depth.
Referring again to Figures 3A and 3B, in the embodiment
illustrated therein, the transport mechanism 66W includes a wire
line 90 operable by a wire line unit 92, substantially as
previously explained and shown in Figure 1. The wire line 90 can
comprise a slick line, an electric line, a braided line, or coil
tubing. If the controller 118, or the computer 122, is ,located at
2o the surface 60, the wire line 90 can be used to establish signal
communication between the reader device 70 and the controller
118 or the computer 122.
Referring to Figures 6A-6D, alternate embodiment transport
mechanisms for transporting the perforating tool 68 and the
reader device 70 through the casing 56 are shown. In Figure 6A, a
transport mechanism 66P comprises a pump for pumping a
conveyance fluid through the inside diameter of the casing 56.
The pumped conveyance fluid then transports the perforating tool
68 and the reader device 70 through the casing 56. In Figure 6B,
3o a transport mechanism 66R comprises one or more robotic
devices attached to the perforating tool 68 and the reader device
70, and configured to transport the perforating tool 68 and the
reader device 70 through the casing 56. In Figure 6C, a transport
mechanism 66G comprises gravity (G) such that the perforating
tool 68 and the reader device 70 free fall through the casing 56.
The free fall can be through a well fluid within the casing 56, or
through air in the casing 56. In Figure 6D, a transport mechanism
66PA includes a parachute which controls the rate of descent of
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the perforating tool 68 and the reader device 70 in the casing 56.
Again, the parachute can operate in a well fluid, or in air
contained in the casing 56.
Referring to Figures 7A-7C, an alternate embodiment
system 50A constructed in accordance with the invention is
illustrated. The system 50A is installed in a subterranean well
52A, such as an oil and gas production well. In this embodiment
the system 50A is configured to perform a packer setting process
in the well 52A.
1o The well 52A includes a well bore 54A, and a well casing
56A within the well bore 54A surrounded by concrete 58A. The
well casing 56A comprises a plurality of tubular elements 62A,
such as lengths of metal pipe or tubing, connected to one another
by collars 64A. The well 52A extends from an earthen surface
60A through geological formations within the earth, which are
represented as Zones H and I.
For performing the packer setting process, the system 50A
includes a packer setting tool 68A, an inflation device 98A for
the packer setting tool 68A, and a reader device 70A in signal
2o communication with the packer setting tool 68A. In this
embodiment, the inflation device 98A is located on the surface
60A such that a wire, or other signal transmission medium must
be provided between the packer setting tool 68A and the inflation
device 98A. The packer setting tool 68A can include an
inflatable packer element designed for inflation by the inflation
device 98A and configured to sealingly engage the inside diameter
of the casing 56A. In Figure 7B, the inflatable packer element of
the packer setting tool 68A has been inflated to seal the inside
diameter of the casing 56A proximate to Zone I.
3o The system 50A also includes a plurality of identification
devices 72 (Figure 3D) attached to the collars 64A on the casing
56A, and readable by the reader device 70A. In addition, the
system 50A includes a transport mechanism 66A for transporting
the packer setting tool 68A and the reader device 70A through the
well casing 56A to Zone I. In this embodiment, the transport
mechanism 66A comprises a tubing string formed. by tubular
elements 102A. As shown in Figure 7C, each tubular element
102A includes a male tool joint 94A on one end, and a female tool
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joint g6A on an opposing end. This permits the tubular elements
102A to be attached to one another to form the transport
mechanism 66A. In addition, the packer setting tool 68A can
include a central mandrel in fluid communication with the inside
diameter of the transport mechanism 66A.
The reader device 70A is programmed to transmit a control
signal to the inflation device 98A upon actuation by a selected
identification device 72 (Figure 3D). For example, in the packer
setting process illustrated in Figures 7A and 7B, coupling C4A is
so located proximate to the upper level, or entry point into Zone I.
Since it is desired to inflate the inflatable packer element of the
packer setting too! 68A while it is proximate to Zone I, the reader
device 70A can be programmed to transmit the control signal to
the inflation device 68A when it reaches coupling C4A. In this
15 embodiment a spacer element 88A separates the packer setting
tool 68A and the reader device 70A. In addition, the packer
setting tool 68A is located downhole relative to the reader device
70A.
In order to insure that the packer setting sequence is
2o initiated at the right time additional factors must be considered
as previously explained. These factors can include the velocity
(V) of the packer setting tool 68A and the reader device 70A, and
the time required to inflate the inflatable packer element of the
packer setting tool 68A. Alternately, the packer setting tool 68A
25 can be stopped at a particular coupling (e.g., coupling C5A) and
then inflated as required. In this case the reader device 70A can
be programmed to transmit the control signals to the visual
display 124 (Figure 4B) on the surface 60A when the packer tool
68A passes a coupling 64A at the required depth. The operator
3o can then control the inflation device 98A to initiate inflation of
the packer setting tool 68A. Alternately the inflation sequence
can be initiated automatically by the tool control circuit 120
(Figure 4A).
In each of the described processes the method of the
35 invention provides an improved well. For example, in the
perforating process of Figures 3A and 3B, the well 52 can be
perforated in the selected zone, or in a selected interval of the
selected zone. Production from the well 52 is thus optimized and
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the well 52 is able to produce more fluids, particularly oil and
gas.
Referring to Figures 8A-8C, a multi stage operation
performed in accordance with the method of the invention is
illustrated. Initially, as shown in Figure 8A, a combination tool
130 is provided. The combination tool 134 includes a packer
setting tool 132 and a perforating tool 134, which function
substantially as previously described for the packer setting tool
68A (Figure 7B), and the perforating tool 68 (Figure 3A)
1o previously described. In addition, the combination tool 134
includes the reader device 70 and the casing 56 includes
identification devices 72 (Figure 3D) substantially as previously
described. As also shown in Figure 8A, the combination tool 130
is transported through the casing 56 using the gravity transport
mechanism 66G. Alternately, any of the other previously
described transport mechanisms can be employed.
Next, as shown in Figure 8B, the packer setting tool 132 is
actuated such that an inflatable packer element of the tool 132
seals the casing 56 at a desired depth. In this embodiment the
2o packer setting tool 132 is a self contained unit, with an integral
inflation source. As with the previously described embodiments,
the reader device 70 provides control signals for controlling the
packer setting tool 132, and the packer setting process. For
example, the inflatable packer element of the packer setting tool
132 can be inflated when the reader device 70 passes a selected
coupling 64, and receives a response signal from the
identification device 72 contained within the selected coupling
64. As also shown in Figure 8B, the perforating tool 134
separates from the packer setting tool 132 and continues to free
3o fall through the casing 56.
Next, as shown in Figure 8C, the perforating tool 132 is
controlled such that detonation and explosive sequences are
initiated substantially as previously described. Again the reader
device 70 provides control signals, for controlling the perforating
tool 132 to initiate the detonation and explosive sequences at the
proper depth. As indicated by the dashed arrows in Figure 8C
explosion of the charge assemblies 80 (Figure 3C) of the
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perforating tool 134 forms openings in the casing 58 and the
concrete 58.
Thus the invention provides a method and a system for
performing various operations or -processes in wells and for
improving production from the wells. While the invention has
been described with reference to certain preferred embodiments,
as will be apparent to those skilled in the art, certain changes
and modifications can be made without departing from the scope
of the invention as defined by the following claims.
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