U.S. patent application number 12/327019 was filed with the patent office on 2010-06-03 for system and method for verifying perforating gun status prior to perforating a wellbore.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. Invention is credited to John D. Burleson, Kevin D. Fink, John H. Hales.
Application Number | 20100133004 12/327019 |
Document ID | / |
Family ID | 41718521 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100133004 |
Kind Code |
A1 |
Burleson; John D. ; et
al. |
June 3, 2010 |
System and Method for Verifying Perforating Gun Status Prior to
Perforating a Wellbore
Abstract
A system for verifying perforating gun status prior to
perforating a wellbore. The system includes a perforating gun (38)
having a leak sensor disposed therein that is positionable at a
target location within the wellbore on a tubing string (30). A
communication system (42, 44, 46, 48, 50) is integrated with the
tubing string (30). The communication system (42, 44, 46, 48, 50)
is operable to communicate with the leak sensor. A surface
controller (40) is operable to send a first telemetry signal via
the communication system (42, 44, 46, 48, 50) to interrogate the
leak sensor regarding a leak status of the perforating gun (38),
receive a second telemetry signal from the leak sensor via the
communication system (42, 44, 46, 48, 50) including the leak status
of the perforating gun (38) and determine whether to operate the
perforating gun (38) based upon the leak status information.
Inventors: |
Burleson; John D.; (Denton,
TX) ; Hales; John H.; (Frisco, TX) ; Fink;
Kevin D.; (Frisco, TX) |
Correspondence
Address: |
LAWRENCE R. YOUST;Lawrence Youst PLLC
2900 McKinnon, Suite 2208
DALLAS
TX
75201
US
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Carrollton
TX
|
Family ID: |
41718521 |
Appl. No.: |
12/327019 |
Filed: |
December 3, 2008 |
Current U.S.
Class: |
175/2 ;
340/854.4; 367/82; 73/152.54 |
Current CPC
Class: |
E21B 47/117 20200501;
E21B 47/14 20130101; E21B 43/116 20130101; E21B 43/119
20130101 |
Class at
Publication: |
175/2 ; 367/82;
340/854.4; 73/152.54 |
International
Class: |
E21B 43/116 20060101
E21B043/116; E21B 47/12 20060101 E21B047/12; E21B 47/16 20060101
E21B047/16; E21B 47/14 20060101 E21B047/14 |
Claims
1. A method for verifying perforating gun status prior to
perforating a wellbore comprising: running a perforating gun having
a leak sensor disposed therein to a target location within the
wellbore on a tubing string; integrating a communication system
with the tubing string, the communication system operable to
communicate with the leak sensor; sending a first telemetry signal
via the communication system to interrogate the leak sensor
regarding a leak status of the perforating gun; returning a second
telemetry signal from the leak sensor via the communication system
including the leak status of the perforating gun; and determining
whether to operate the perforating gun based upon the leak status
information.
2. The method as recited in claim 1 wherein running the perforating
gun having a leak sensor disposed therein further comprises running
the perforating gun having a moisture sensor disposed therein.
3. The method as recited in claim 1 wherein running the perforating
gun having a leak sensor disposed therein further comprises running
the perforating gun having a pressure sensor disposed therein.
4. The method as recited in claim 1 wherein integrating a
communication system with the tubing string further comprises
integrating an acoustic communication system with the tubing
string.
5. The method as recited in claim 1 wherein sending a first
telemetry signal via the communication system to interrogate the
leak sensor regarding a leak status of the perforating gun further
comprises sending an acoustic signal encoded with the leak status
request.
6. The method as recited in claim 1 wherein returning a second
telemetry signal from the leak sensor via the communication system
including the leak status of the perforating gun further comprises
returning an acoustic signal encoded with the leak status
information.
7. The method as recited in claim 1 wherein determining whether to
operate the perforating gun based upon the leak status information
further comprises determining whether to operate the perforating
gun based upon moisture status information.
8. The method as recited in claim 1 wherein determining whether to
operate the perforating gun based upon the leak status information
further comprises determining whether to operate the perforating
gun based upon pressure status information.
9. A method for verifying perforating gun system status prior to
perforating a wellbore comprising: running the perforating gun
system to a target location within the wellbore on a tubing string,
the perforating gun system including a plurality of perforating
guns each having a leak sensor disposed therein; integrating a
communication system with the tubing string, the communication
system operable to communicate with the leak sensors; sending first
telemetry signals via the communication system to interrogate the
leak sensors regarding a leak status of each of the perforating
guns; returning second telemetry signals from the leak sensors via
the communication system including the leak status of each of the
perforating guns; and determining whether to operate the
perforating gun system based upon the leak status information.
10. The method as recited in claim 9 further comprises selecting
the leak sensors from moisture sensors and pressure sensors.
11. The method as recited in claim 9 wherein integrating a
communication system with the tubing string further comprises
integrating an acoustic communication system with the tubing
string.
12. A system for verifying perforating gun status prior to
perforating a wellbore comprising: a perforating gun having a leak
sensor disposed therein positioned at a target location within the
wellbore on a tubing string; a communication system integrated with
the tubing string, the communication system operable to communicate
with the leak sensor; and a surface controller operable to send a
first telemetry signal via the communication system to interrogate
the leak sensor regarding a leak status of the perforating gun,
receive a second telemetry signal from the leak sensor via the
communication system including the leak status of the perforating
gun and determine whether to operate the perforating gun based upon
the leak status information.
13. The system as recited in claim 12 wherein the leak sensor
further comprises a moisture sensor.
14. The system as recited in claim 12 wherein the leak sensor
further comprises a pressure sensor.
15. The system as recited in claim 12 wherein the communication
system further comprises an acoustic communication system.
16. A method for verifying an environmental condition relative to a
perforating gun disposed in a wellbore comprising: running the
perforating gun having at least one environmental sensor associated
therewith to a target location within the wellbore on a tubing
string; integrating a communication system with the tubing string,
the communication system operable to communicate with the
environmental sensor; sending a first telemetry signal via the
communication system to interrogate the environmental sensor
regarding an environmental condition relative to the perforating
gun; and returning a second telemetry signal from the environmental
sensor via the communication system including the environmental
condition relative to the perforating gun.
17. The method as recited in claim 16 wherein running the
perforating gun having at least one environmental sensor associated
therewith to a target location within the wellbore on a tubing
string further comprises selecting the at least one environmental
sensor from at least one of a moisture sensor, a pressure sensor, a
temperature sensor, an accelerometer, a shock load sensor, a liner
displacement sensor, a depth sensor and a fluid sensor.
18. The method as recited in claim 16 wherein running the
perforating gun having at least one environmental sensor associated
therewith to a target location within the wellbore on a tubing
string further comprises disposing the at least one environmental
sensor interior of the perforating gun.
19. The method as recited in claim 16 wherein running the
perforating gun having at least one environmental sensor associated
therewith to a target location within the wellbore on a tubing
string further comprises disposing the at least one environmental
sensor exterior of the perforating gun.
20. The method as recited in claim 16 wherein integrating a
communication system with the tubing string further comprises
integrating an acoustic communication system with the tubing
string.
21. The method as recited in claim 16 wherein sending a first
telemetry signal via the communication system to interrogate the
environmental sensor regarding an environmental condition relative
to the perforating gun further comprises sending an acoustic signal
encoded with the environmental condition request.
22. The method as recited in claim 16 wherein returning a second
telemetry signal from the environmental sensor via the
communication system including the environmental condition relative
to the perforating gun further comprises returning an acoustic
signal encoded with the environmental condition information.
23. The method as recited in claim 16 further comprising
determining whether to operate the perforating gun based upon the
environmental condition.
24. A system for verifying an environmental condition relative to a
perforating gun disposed in a wellbore comprising: at least one
environmental sensor associated with the perforating gun positioned
at a target location within the wellbore on a tubing string; a
communication system integrated with the tubing string, the
communication system operable to communicate with the environmental
sensor; and a surface controller operable to send a first telemetry
signal via the communication system to interrogate the
environmental sensor regarding an environmental condition relative
to the perforating gun and receive a second telemetry signal from
the environmental sensor via the communication system including the
environmental condition relative to the perforating gun.
25. The system as recited in claim 24 wherein the communication
system further comprises an acoustic communication system.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates, in general, to opening communication
paths through a casing disposed in a wellbore and, in particular,
to systems and methods for verifying the status of perforating guns
prior to perforating the wellbore.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its
background will be described in relation to perforating a wellbore,
as an example.
[0003] After drilling the various sections of a subterranean
wellbore that traverses a formation, individual lengths of
relatively large diameter metal tubulars are typically secured
together to form a casing string that is positioned within the
wellbore. This casing string increases the integrity of the
wellbore and provides a path for producing fluids from the
producing intervals to the surface. Conventionally, the casing
string is cemented within the wellbore. To produce fluids into the
casing string, hydraulic openings or perforations must be made
through the casing string, the cement and a distance into the
formation.
[0004] Typically, these perforations are created by detonating a
series of shaped charges that are disposed within the casing string
and are positioned adjacent to the formation. Specifically, one or
more charge carriers or perforating guns are loaded with shaped
charges that are connected with a detonator via a detonating cord.
The charge carriers are then connected within a tool string that is
lowered into the cased wellbore at the end of a tubing string or
other conveyance. Once the charge carriers are properly positioned
in the wellbore such that the shaped charges are adjacent to the
formation to be perforated, the shaped charges may be fired. If
more than one downhole zone is to be perforated, a select fire
perforating gun assembly may be used such that once the first zone
is perforated, subsequent zones may be perforated by repositioning
and firing the previously unfired perforating guns without tripping
out of the well.
[0005] Typically, once the perforating guns are assembled, the
charge carriers protect the shaped charges disposed therein against
wellbore fluids. It has been found, however, that perforating guns
sometimes develop a leak, for example during the run in process,
and become partially or completely filled with wellbore fluid. Once
such fluid infiltration has occurred, if such a perforating gun is
fired, there is a high likelihood that the perforating gun may
split. Not only does such an occurrence result in a failed
perforation operation, the explosive event may damage other
wellbore equipment and may result in the split perforating gun
becoming lodged in the wellbore. As such, an expensive recovery
effort to retrieve the damaged equipment may be required and the
entire completion may have to be abandoned resulting in the need to
drill a sidetrack well.
[0006] A need has therefore arisen for an apparatus and method for
perforating a cased wellbore that create effective perforation
tunnels. A need has also arisen for such an apparatus and method
that provide for determining whether a perforating gun has
experienced a leak prior to firing the perforating gun.
SUMMARY OF THE INVENTION
[0007] The present invention disclosed herein provides systems and
methods for bidirectional communication between a surface system
and a downhole system that enables a determination of whether a
perforating gun has experienced a leak prior to firing the
perforating gun. The systems and methods of the present invention
enable such a determination by telemetering encoded signals from
the surface system to one or more downhole systems requesting leak
status and other environmental information and by telemetering
encoded signals from the downhole systems to the surface system
including the leak status or other requested environmental
information.
[0008] In one aspect, the present invention is directed to a method
for verifying perforating gun status prior to perforating the
wellbore. The method includes running a perforating gun having a
leak sensor disposed therein to a target location within the
wellbore on a tubing string, integrating a communication system
with the tubing string, the communication system operable to
communicate with the leak sensor, sending a first telemetry signal
via the communication system to interrogate the leak sensor
regarding a leak status of the perforating gun, returning a second
telemetry signal from the leak sensor via the communication system
including the leak status of the perforating gun and determining
whether to operate the perforating gun based upon the leak status
information.
[0009] In one embodiment, the leak sensor may be a moisture sensor.
In this embodiment, the method may include determining whether to
operate the perforating gun based upon moisture status information.
In another embodiment, the leak sensor may be a pressure sensor. In
this embodiment, the method may include determining whether to
operate the perforating gun based upon pressure status information.
In a further embodiment, the communication system may be an
acoustic communication system that is integrated with the tubing
string. In this embodiment, the method may include sending an
acoustic signal encoded with the leak status request to the leak
sensor and returning an acoustic signal encoded with the leak
status information from the leak sensor.
[0010] In another aspect, the present invention is directed to a
method for verifying perforating gun system status prior to
perforating a wellbore. This method includes running the
perforating gun system to a target location within the wellbore on
a tubing string, the perforating gun system including a plurality
of perforating guns each having a leak sensor disposed therein,
integrating a communication system with the tubing string, the
communication system operable to communicate with the leak sensors,
sending first telemetry signals via the communication system to
interrogate the leak sensors regarding a leak status of each of the
perforating guns, returning second telemetry signals from the leak
sensors via the communication system including the leak status of
each of the perforating guns and determining whether to operate the
perforating gun system based upon the leak status information.
[0011] In a further aspect, the present invention is directed to a
system for verifying perforating gun status prior to perforating a
wellbore. The system includes a perforating gun having a leak
sensor disposed therein. The perforating gun may be deployed on a
tubing string and positioned at a target location within the
wellbore. A communication system is integrated with the tubing
string. The communication system is operable to communicate with
the leak sensor. A surface controller is operable to send a first
telemetry signal via the communication system to interrogate the
leak sensor regarding a leak status of the perforating gun, receive
a second telemetry signal from the leak sensor via the
communication system including the leak status of the perforating
gun and determine whether to operate the perforating gun based upon
the leak status information.
[0012] In yet another aspect, the present invention is directed to
a method for verifying an environmental condition relative to a
perforating gun disposed in a wellbore. The method includes running
the perforating gun having at least one environmental sensor
associated therewith to a target location within the wellbore on a
tubing string, integrating a communication system with the tubing
string, the communication system operable to communicate with the
environmental sensor, sending a first telemetry signal via the
communication system to interrogate the environmental sensor
regarding an environmental condition relative to the perforating
gun and returning a second telemetry signal from the environmental
sensor via the communication system including the environmental
condition relative to the perforating gun.
[0013] In one embodiment, the environmental sensor may include one
or more of a moisture sensor, a pressure sensor, a high speed
pressure sensor, a temperature sensor, an accelerometer, a shock
load sensor, a liner displacement sensor, a depth sensor and a
fluid sensor. These environmental sensors may be disposed interior
of the perforating gun, exterior of the perforating gun or in the
vicinity of the perforating gun. In another embodiment, the
communication system may be an acoustic communication system that
enables sending of an acoustic signal encoded with the
environmental condition request and returning an acoustic signal
encoded with the environmental condition information.
[0014] In an additional aspect, the present invention is directed
to a system for verifying an environmental condition relative to a
perforating gun disposed in a wellbore. At least one environmental
sensor is associated with the perforating gun which is positioned
at a target location within the wellbore on a tubing string. A
communication system is integrated with the tubing string. The
communication system is operable to communicate with the
environmental sensor. A surface controller is operable to send a
first telemetry signal via the communication system to interrogate
the environmental sensor regarding an environmental condition
relative to the perforating gun and receive a second telemetry
signal from the environmental sensor via the communication system
including the environmental condition relative to the perforating
gun.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a more complete understanding of the present invention,
including its features and advantages, reference is now made to the
detailed description of the invention, taken in conjunction with
the accompanying drawings in which like numerals identify like
parts and in which:
[0016] FIG. 1 is a schematic illustration of an offshore oil and
gas platform operating a system for verifying the status of
perforating guns prior to perforating a wellbore that embodies
principles of the present invention;
[0017] FIG. 2 is a partial cut away view of a perforating gun for
use in a system for verifying the status of perforating guns prior
to perforating a wellbore that embodies principles of the present
invention; and
[0018] FIG. 3 is a flow chart illustrating a method for verifying
the status of perforating guns prior to perforating a wellbore that
embodies principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] While the making and using of various embodiments of the
present invention are discussed in detail below, it should be
appreciated that the present invention provides many applicable
inventive concepts which can be embodied in a wide variety of
specific contexts. The specific embodiments discussed herein are
merely illustrative of specific ways to make and use the invention,
and do not delimit the scope of the invention.
[0020] Referring initially to FIG. 1, a system for verifying the
status of perforating guns prior to perforating a wellbore is
operating from an offshore oil and gas platform that is
schematically illustrated and generally designated 10. A
semi-submersible platform 12 is centered over a submerged oil and
gas formation 14 located below sea floor 16. A subsea conduit 18
extends from deck 20 of platform 12 to wellhead installation 22
including subsea blow-out preventers 24. Platform 12 has a hoisting
apparatus 26 and a derrick 28 for raising and lowering pipe strings
such as work sting 30.
[0021] A wellbore 32 extends through the various earth strata
including formation 14. A casing 34 is cemented within wellbore 32
by cement 36. Work string 30 includes various tools such as a
plurality of perforating guns 38 disposed in a generally horizontal
portion of wellbore 32 and a communication system including
communication nodes 42, 44, 46, 48, 50. In the illustrated
embodiment, a surface communication node or controller 40 provides
a user interface including, for example, input and output devices
such as one or more video screens or monitors, including touch
screens, one or more keyboards or keypads, one or more pointing or
navigation devices, as well as any other user interface devices
that are currently known to those skilled in the art or are
developed. The user interface may take the form of a computer
including a notebook computer. In addition, surface controller 40
may include a logic module having various controllers, processors,
memory components, operating systems, instructions, communication
protocols and the like for implementing the systems and methods for
verifying the status of perforating guns of the present invention.
Surface controller 40 is coupled to a bidirectional communication
link that provides for communication between surface controller 40
and a node 42 that is positioned in the well as part of or attached
to work string 30.
[0022] The bidirectional communication link includes at least one
communication path from surface controller 40 to node 42 and at
least one communication path from node 42 to surface controller 40.
In certain embodiments, bidirectional communication may be achieved
via a half duplex channel which allows only one communication path
to be open in any time period. Preferably, bidirectional
communication is achieved via a full duplex channel which allows
simultaneous communication over multiple communication paths. This
can be achieved, for example, by providing independent hardwire
connections or over a shared physical media through frequency
division duplexing, time division duplexing, echo cancellation or
similar technique. In either case, the communication link may
include one or more electrical conductors, optical conductors or
other physical conductors.
[0023] Each of communication nodes 42, 44, 46, 48, 50 includes a
transmitter, a receiver and a logic module that includes, for
example, various fixed logic circuits, controllers, processors,
memory components, operating systems, instructions, communication
protocols and the like for implementing the systems and methods for
verifying the status of perforating guns of the present invention.
In addition, each communication node 42, 44, 46, 48, 50 also
includes a power supply such as a battery pack which may include a
plurality of batteries, such as nickel cadmium, lithium, alkaline
or other suitable power source, which are configured to provide
proper operating voltage and current.
[0024] In one embodiment, communication nodes 42, 44, 46, 48, 50
are operable to transmit and receive acoustic signals that are
propagated over work string 30. In this case, the transmitters and
receivers of communication nodes 42, 44, 46, 48, 50 preferably
include one or more transducers in the form of stacks of
piezoelectric ceramic crystals. It should be noted that a single
transducer may operated as both the transmitter and the receiver of
a given communication node. Any number of communication nodes may
be operated in the system of the present invention with the number
determined by the length of work string 30, the noise in the
wellbore, the type of communication media used and the like. As
illustrated, communication nodes 44, 46, 48 serve as repeater that
are positioned to receive the acoustic signals transmitted along
work string 30 at a point where the acoustic signals are of a
magnitude sufficient for adequate reception. Once the acoustic
signals reach a given node, the signals are converted to an
electrical current which represents the information being
transmitted and is fed to the logic module for processing. The
current is then sent to the transducer to generate acoustic signals
that are transmitted to the next node. In this manner,
communication from node 40 to node 50 as well as from node 50 to
node 40 is achieved.
[0025] When it is desired to perforate casing 34, work string 30 is
lowered through casing 34 until the perforating guns 38 are
properly positioned relative to formation 14. To verify the
condition of perforating guns 38 prior to the perforating
operation, an interrogation command may be sent from surface
controller 40 to sensors disposed in perforating guns 38. For
example, as discussed in greater detail below, each perforating gun
38 may include one or more sensors such as moisture sensors,
pressure sensors or other leak sensors. Preferably, each of these
sensors is individually addressable and communicates with
communication node 50 via a wired connection but a short range
wireless connection such as an electromagnetic communication link
could alternatively be used.
[0026] Accordingly, when surface controller 40 sends interrogation
commands to determine the leak status of perforating guns 38 to one
or more of the sensors, the commands are received by communication
node 42 and retransmitted as encoded acoustic signals along work
string 30 which are received by communication node 44.
Communication node 44 acts as a repeater to receive, process and
retransmit the commands via acoustic signals along work string 30
which are received by communication node 46. Likewise,
communication node 46 forwards the commands to communication node
48 via acoustic signals along work string 30 and communication node
48 forwards the commands to communication node 50 via acoustic
signals along work string 30. Communication node 50 then sends the
commands to interrogate each of the sensors in perforating guns 38.
The sensors obtain the desired data regarding the leak status of
each perforating gun 38 and provide this information to
communication node 50. Communication node 50 converts this
information to acoustic signals that are sent to communication node
48 along work string 30. Communication nodes 48, 46, 44 act as
repeaters, each receiving, processing and retransmitting the
information in the form of acoustic signals along work string 30.
Communication node 42 receives the acoustic signals send from
communication node 44 and processes the information such that it
can be forwarded to surface controller 40 for analysis.
[0027] If the sensors report that no leaks have been identified
within perforating guns 38, then the communication system may be
used in a similar manner to enable, arm and fire perforating guns
38 using, for example, one or more electronic or hydraulic firing
heads. Thereafter, the shaped charges within perforating guns 38
are sequentially fired, either in an uphole to downhole or a
downhole to uphole direction. Upon detonation, the liners of the
shaped charges form jets that create a spaced series of
perforations extending outwardly through casing 34, cement 36 and
into formation 14, thereby allow fluid communication between
formation 14 and wellbore 32.
[0028] In the illustrated embodiment, wellbore 32 has an initial,
generally vertical portion and a lower, generally deviated portion
which is illustrated as being horizontal. It should be noted,
however, by those skilled in the art that the system for verifying
the status of perforating guns of the present invention is equally
well-suited for use in other well configurations including, but not
limited to, inclined wells, wells with restrictions, non-deviated
wells and the like. In addition, even though FIG. 1 has been
described with reference to an offshore environment, it should be
understood by one skilled in the art that the principles described
herein are equally well-suited for an onshore environment.
[0029] As should be understood by those skilled in the art, any of
the functions described with reference to a logic module herein can
be implemented using software, hardware, including fixed logic
circuitry, manual processing or a combination of these
implementations. As such, the term "logic module" as used herein
generally represents software, hardware or a combination of
software and hardware. For example, in the case of a software
implementation, the term "logic module" represents program code
and/or declarative content, e.g., markup language content, that
performs specified tasks when executed on a processing device or
devices such as one or more processors or CPUs. The program code
can be stored in one or more computer readable memory devices. More
generally, the functionality of the logic modules may be
implemented as distinct units in separate physical grouping or can
correspond to a conceptual allocation of different tasks performed
by a single software program and/or hardware unit. The logic
modules can be located at a single site such as implemented by a
single processing device, or can be distributed over plural
locations such as a notebook computer or personal digital assistant
in combination with other physical devices that communication with
one another via wired or wireless connections.
[0030] Referring next to FIG. 2, therein is depicted a perforating
gun for use in the system for verifying the status of perforating
guns of the present invention that is generally designated 100.
Perforating gun 100 includes a carrier 102 having a plurality of
recesses, such as recess 104, defined therein. Radially aligned
with each of the recesses is a respective one of the plurality of
shaped charges, such as shaped charge 106.
[0031] The shaped charges are retained within carrier 102 by a
support member 108 which includes an outer charge holder sleeve 110
and an inner charge holder sleeve 112. In this configuration, outer
tube 110 supports the discharge ends of the shaped charges, while
inner tube 112 supports the initiation ends of the shaped charges.
Disposed within inner tube 112 is a detonating cord 116. In the
illustrated embodiment, the initiation ends of the shaped charges
extend across the central longitudinal axis of perforating gun 100
allowing detonating cord 116 to connect to the high explosive
within the shaped charges through an aperture defined at the apex
of the housings of the shaped charges. In this configuration,
carrier 102 is sealed to protect the shaped charges disposed
therein against wellbore fluids.
[0032] Each of the shaped charges, such as shaped charge 106, is
longitudinally and radially aligned with a recess, such as recess
104, in carrier 102 when perforating apparatus 100 is fully
assembled. In the illustrated embodiment, the shaped charges are
arranged in a spiral pattern such that each shaped charge is
disposed on its own level or height and is to be individually
detonated so that only one shaped charge is fired at a time. It
should be noted, however, by those skilled in the art that
alternate arrangements of shaped charges may be used, including
cluster type designs wherein more than one shaped charge is at the
same level and is detonated at the same time, without departing
from the principles of the present invention.
[0033] As discussed above, perforating guns for use in the system
for verifying the status of perforating guns of the present
invention, such as perforating gun 100, include one or more sensors
used to obtain and provide information relative to environmental
factors that surround perforating gun 100. In the illustrated
embodiment, perforating gun 100 includes a plurality of sensors
such as sensor 120 positioned on the exterior of support member
108, sensor 122 positioned on the interior of support member 108,
sensor 124 positioned on the interior of carrier 102 and sensor 126
positioned on the exterior of carrier 102. As discussed above,
sensors 120, 122, 124, 126 are preferably coupled to communication
node 50 via a wired connection but other communication means are
also possible and considered within the scope of the present
invention.
[0034] Sensors 120, 122, 124, 126 may be of the same type or
different types and may be moisture sensors, humidity sensors,
pressure sensors including high speed pressure sensors or fast
gauge sensors, temperature sensors, accelerometers, shock load
sensors, liner displacement sensors, depth sensors, fluid sensors,
CO.sub.2 sensors, H.sub.2S sensors, CO sensors, thermal
decomposition sensors, casing collar locators, gamma detectors or
any other types of sensors that are operable to provide information
relating to the perforating gun environment. Sensors 120, 122, 124,
126 and similar sensors associated with the perforating gun system
may be used for monitoring a variety of environmental conditions
relative to the gun string such as the depth and orientation of the
guns in the wellbore; the condition of the guns prior to firing
including leak status, pressure, thermal decomposition and
moisture; whether the guns fired properly including gun pressures,
accelerations and shock loads; the near wellbore reservoir
parameters including temperatures, hydrostatic pressures, peak
pressures and transient pressures as well as other environmental
conditions that are known to those skilled in the art.
[0035] The operation of one embodiment of the present invention
will now be described as process 200 with reference to FIG. 3. Once
the perforating guns 38 are positioned at the target location in
the wellbore (step 202) and prior to detonating the shaped charges,
the system of the present invention is operable to perform a
variety of gun condition verifications such as those described
above and including perforating gun depth and orientation
verification and perforating guns condition verification. This
verification is accomplished using the surface controller in
conjunction with the communication nodes positioned along the work
string to interrogate the sensors associated with the perforating
guns for the desired information. As an example, an interrogation
command requesting the leak status of one of the perforating guns
is sent to one of the downhole sensors via the communication nodes
and the work string and that downhole sensor responds with the
requested information also via the communication nodes and the work
string (step 204). Next, the surface controller determines whether
all the sensors have been interrogated (decision 206). If all of
the sensors have not been interrogated, an interrogation command
requesting the leak status of another of the perforating guns is
sent to another of the downhole sensors and that downhole sensor
responds with the requested information (step 208). This process
continues until all of the sensors have been interrogated (decision
206).
[0036] Once all of the sensors have been interrogated, the surface
controller determines whether all of the perforating guns are dry
(decision 210). If all of the perforating guns are dry, the surface
controller may proceed with the remainder of the firing sequence
including sending the appropriate enable, arm and fire commands via
the communication nodes to a suitable firing head (step 212). If
all of the perforating guns are not dry, the surface controller
determines whether remedial action can be taken to allow the
perforating event to occur (decision 214). Such remedial action may
include repeating the verification process to determine if the out
of range condition persists, identifying which guns have an out of
range condition and removing those guns from the firing sequence or
the like. If in performing such remedial action the surface
controller determines that the perforating event should occur, then
the surface controller may proceed with the remainder of the firing
sequence (step 212). If in performing such remedial action it is
determined that the perforating event may not occur, then the
process ends.
[0037] During the perforating event, the sensors associated with
the perforating guns may continue gather and transmit information.
Specifically, sensors such as the above described accelerometers,
pressure sensors, high speed pressure sensors, temperature sensors
and the like are used to obtain a variety of perforating gun and
near wellbore reservoir data. For example, the high speed pressure
sensors are operably to obtain pressure data in the millisecond
range such that the pressure surge and associated pressure cycles
created by the perforating event can be measured. Likewise, the
accelerometers are operable to record shock data associated with
the perforating event. Use of this and other data provide for a
determination of the intensity level of the detonation associated
with the perforating guns. During, immediately after or at a later
time, this information is communicated from the sensors to the
surface controller over the communication system. This information
may be used to determine the quality of the perforating event such
as whether the initiator was detonated, whether any of the shaped
charges within the perforating gun were detonated, whether all of
the shaped charges within the perforating gun were detonated or
whether only some of the shaped charges within the perforating gun
were detonated. This information will allow the operator in
substantially real time to determine, for example, if a zone should
be reperforated.
[0038] Likewise, following the perforating event, the sensors
associated with the perforating guns may continue gather and
transmit information. Specifically, sensors such as the above
described pressure sensors, temperature sensors, fluid sensors and
the like are used to obtain a variety of near wellbore reservoir
data. This data may be useful in designing the next phase of the
completion such as whether to perform an acid job or a facture
stimulation.
[0039] While this invention has been described with a reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments as well as other
embodiments of the invention, will be apparent to persons skilled
in the art upon reference to the description. It is, therefore,
intended that the appended claims encompass any such modifications
or embodiments.
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