U.S. patent application number 11/701333 was filed with the patent office on 2007-06-21 for data relay system for casing mounted sensors, actuators and generators.
This patent application is currently assigned to Halliburton Energy Services, Inc., a Delaware corp. Invention is credited to Jean Michel Beique, Morris Benjamin Robbins.
Application Number | 20070139217 11/701333 |
Document ID | / |
Family ID | 22969121 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070139217 |
Kind Code |
A1 |
Beique; Jean Michel ; et
al. |
June 21, 2007 |
Data relay system for casing mounted sensors, actuators and
generators
Abstract
A casing sensor and methods for sensing using a casing sensor
are disclosed. The casing sensor includes a casing shoe and a
sensor coupled to the casing shoe. A casing data relay includes a
downhole receiver coupled to a well casing and a transmitter
coupled to the receiver. The casing sensor may be coupled to the
transmitter. A drill string actuator may be controllable through
the downhole receiver.
Inventors: |
Beique; Jean Michel;
(Rockwall, TX) ; Robbins; Morris Benjamin;
(Mandeville, LA) |
Correspondence
Address: |
FISH & RICHARDSON P.C.
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Assignee: |
Halliburton Energy Services, Inc.,
a Delaware corp
|
Family ID: |
22969121 |
Appl. No.: |
11/701333 |
Filed: |
February 1, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10167737 |
Jun 11, 2002 |
7173542 |
|
|
11701333 |
Feb 1, 2007 |
|
|
|
09255612 |
Feb 19, 1999 |
6429784 |
|
|
10167737 |
Jun 11, 2002 |
|
|
|
Current U.S.
Class: |
340/856.3 ;
340/854.3 |
Current CPC
Class: |
E21B 47/06 20130101;
E21B 47/005 20200501; E21B 47/12 20130101; E21B 47/00 20130101;
E21B 17/14 20130101; E21B 47/14 20130101; E21B 47/07 20200501; G01V
11/002 20130101; E21B 47/01 20130101; E21B 21/08 20130101 |
Class at
Publication: |
340/856.3 ;
340/854.3 |
International
Class: |
G01V 3/00 20060101
G01V003/00 |
Claims
1-37. (canceled)
38. A casing data relay system for use in a wellbore hole,
comprising: at least one downhole instrument attached to a surface
of a well casing disposed in the wellbore hole, said instrument
selected from a group consisting of sensors, actuators and
generators; a controller attached to a surface of the casing, said
controller being coupled to the downhole instrument; and surface
equipment electrically coupled to the controller using an insulated
conductor.
39. A casing data relay system for use in a wellbore hole,
comprising: at least one downhole instrument attached to a surface
of a well casing disposed in the wellbore hole, said instrument
selected from a group consisting of sensors, actuators and
generators; a controller attached to a surface of the casing, said
controller being coupled to the downhole instrument; and surface
equipment optically coupled to the controller using fiber optic
cable.
40. A casing data relay system for use in a wellbore hole,
comprising: at least one downhole instrument attached to a surface
of a well casing disposed in the wellbore hole, said instrument
selected from a group consisting of sensors, actuators and
generators; a controller attached to a surface of the casing, said
controller being coupled to the downhole instrument; and surface
equipment coupled to the controller by electromagnetic
telemetry.
41. A casing data relay system for use in a wellbore hole,
comprising: at least one downhole instrument attached to a surface
of a well casing disposed in the wellbore hole, said instrument
selected from a group consisting of sensors, actuators and
generators; a controller attached to a surface of the casing, said
controller being coupled to the downhole instrument; and surface
equipment coupled to the controller by pulse telemetry using a
pressure transducer.
42. A casing data relay system for use in a wellbore hole,
comprising: at least one downhole instrument attached to a surface
of a well casing disposed in the wellbore hole, said instrument
selected from a group consisting of sensors, actuators and
generators; a controller attached to a surface of the well casing,
said controller being coupled to the downhole instrument; and
surface equipment coupled to the controller by a radio frequency
transmission.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to a method and apparatus
for collecting data regarding geological properties of underground
or undersea formations in the vicinity of a well bore under
construction. More particularly, this invention relates to a method
and apparatus for collecting data regarding the formations during
and after drilling and constructing the well bore. In particular,
the invention relates to a method and apparatus for collecting data
regarding the formations sensors, actuators and generators coupled
to a well casing inside the well bore. This invention also relates
to a method and apparatus for relaying data collected deep in a
well to the surface.
BACKGROUND OF THE INVENTION
[0002] Geologists and geophysicists collect data regarding
underground formations in order to predict the location of
hydrocarbons such as oil and gas. Traditionally, such information
is gathered during an exploration phase. In recent years, however,
the art has advanced to allow the collection of geophysical and
geological data as a well is being drilled.
[0003] For example, in Vertical Seismic Profiling ("VSP"), drilling
operations are interrupted to place a series of seismic sensors at
discrete depths in a borehole. A surface source releases energy
that is reflected off underground geological formations. The
seismic sensors in the borehole sense the reflected energy and
provide signals representing reflections to the surface for
analysis.
[0004] In a subsequent development, known as "drill bit seismic",
seismic sensors are positioned at the surface near the borehole to
sense seismic energy imparted to the earth by the drill bit during
drilling. This sensed energy is used in the traditional seismic way
to detect reflections from underground geological formations.
Further, this technique is used to detect "shadows", or reduced
seismic energy magnitude, caused by underground formations, such as
gas reservoirs, between the drill bit and the surface sensors.
[0005] A greatly simplified description of those steps involved in
drilling an oil well follows. A portion of the oil well is drilled
using a dril string consisting of drill pipe, drill collars and
drill bit. After a portion of the well has been drilled, a section
of casing, or large bore pipe, is inserted into the well bore and
cemented for, among other things, zonal isolation. Casing performs
a number of functions, including: preventing the bore hole from
caving in; preventing fluids in the bore hole from contaminating
the surrounding formations; preventing the introduction of water
into the surrounding formations; containing any production from the
well; facilitating pressure control; providing an environment for
the installation of production equipment; and providing zonal
isolation.
[0006] When the casing is in place it is cemented to the formation
wall. This is accomplished by pumping cement through the casing
until it exits at the end of the casing through a special section
of casing called a "casing shoe" and flows up the annulus between
the casing and the wall of the well bore. The concrete is then
allowed to set.
[0007] In subsequent drilling operations, the deep end of the newly
cemented casing is drilled out and another section of the well bore
is drilled. The process of drilling sections of the well bore
followed by inserting and cementing well casing repeats until the
desired well depth is reached.
[0008] As the well bore is being drilled, drilling fluids, known as
"mud", are pumped into the drill string. The mud travels down the
drill string until it is ejected. The mud picks up cuttings and
carries them to the surface. The specific gravity of the drill mud
is carefully controlled so that the weight of the column of mud is
(1) large enough to prevent gas or other hydrocarbons from entering
the borehole from the surrounding formations; (2) without exerting
so much pressure that the surrounding formations are damaged.
[0009] After each section of casing is laid and cemented in, the
fracture pressure of the formation just below the end of the casing
is measured. Generally, the fracture pressure of deeper formations
is greater than the fracture pressure of shallower formations. The
specific gravity of the drilling mud is subsequently controlled to
make sure that the pressure on the formation at the end of the
casing does not exceed the fracture pressure of the formation at
that point. This is generally accomplished by calculations
incorporating the measured specific gravity of the drilling mud and
the depth of the column of drilling mud above the formation.
[0010] Downhole data are captured using "wireline" techniques in
which, prior to casing being laid, a tool, such as an acoustic
logging tool, is lowered into the well bore and slowly retrieved,
gathering data and storing it or transmitting it to the surface as
the tool is being retrieved. Alternatively, measurement while
drilling ("MWD") or logging while drilling ("LWD") tools are
attached to the drill string just above the drill bit and drill
collars. These generally expensive tools gather data during the
drilling process and store it or transmit it to the surface.
SUMMARY OF THE INVENTION
[0011] In general, in one aspect, the invention features a casing
sensor comprising a casing shoe and a sensor coupled to the casing
shoe.
[0012] Implementations of the invention may include one or more of
the following. The sensor may comprise a pressure sensor. The
sensor pressure may comprise a pressure transducer and a
transmitter coupled to the pressure transducer. The casing sensor
may comprise a surface receiver coupled to the transmitter. The
casing sensor may comprise a drill string through the casing
shoe.
[0013] In general, in another aspect, the invention features a
casing data relay comprising a downhole receiver coupled to a well
casing and a transmitter coupled to the receiver.
[0014] Implementations of the invention may include one or more of
the following. The casing data relay may comprise a surface
receiver coupled to the transmitter. The surface receiver may be
electrically or optically coupled to the transmitter. The surface
receiver may be coupled to the transmitter by electromagnetic
telemetry. The surface receiver may be coupled to the transmitter
by a pressure transducer. The casing data relay may comprise an
antenna coupled to the downhole receiver, the antenna being
configured to receive electromagnetic radiation. The casing data
relay may comprise one or more casing sensors coupled to the
casing, wherein one or more of the one or more casing sensors are
coupled to the transmitter. The casing data relay may comprise one
or more drill string sensors coupled to a drill string. At least a
portion of the drill string may be inserted through the casing. The
drill string sensors may be coupled to the downhole receiver. One
or more of the drill string sensors may be coupled to the downhole
receiver through a drill string transmitter. The casing data relay
may comprise drill string instruments coupled to the transmitter
and a surface transmitter coupled to the downhole receiver. The
casing data relay may comprise a drill string actuator. The drill
string actuator may be controllable through the downhole receiver.
The drill string actuator may be configured to change a position of
an adjustable gauge stabilizer. The drill string actuator may be
configured to change a bit nozzle size.
[0015] In general, in another aspect, the invention features a
method for collecting geological data comprising sensing one or
more geological parameters during drilling using one or more
sensors coupled to a well casing in a well bore, collecting data
from the one or more sensors and transmitting the data to the
surface. Sensing may comprise sensing using one or more sensors
coupled to a casing shoe, sensing using a pressure transducer on a
casing shoe, sensing pressure, sensing temperature, sensing
acoustic energy, sensing stress or sensing strain. The method may
further comprise transmitting acoustic energy. Transmitting may
comprise transmitting the data to the surface through a relay.
[0016] In general, in another aspect, the invention features a
method for maintaining the integrity of a formation in the vicinity
of a casing shoe comprising measuring well bore pressure in the
vicinity of the casing shoe during drilling.
[0017] Implementations of the invention may include one or more of
the following. The method may comprise transmitting data
representing the measured well bore pressure to the surface.
[0018] In general, in another aspect, the invention features a
method for positioning look ahead sensors comprising positioning
acoustic sensors along a casing string.
[0019] In general, in another aspect, the invention features a
method for monitoring well control events comprising monitoring
pressure at two or more locations inside a casing of the well.
[0020] Implementations of the invention may include one or more of
the following. Monitoring may comprise monitoring pressure at two
or more locations that are longitudinally displaced along the
casing.
[0021] In general, in another aspect, the invention features a
method for determining whether cement in a well borehole has cured
comprising positioning a temperature sensor on a casing and
monitoring the temperature of the cement using the temperature
sensor.
[0022] Implementations of the invention may include one or more of
the following. Positioning may comprise positioning the temperature
sensor inside the casing or positioning the temperature sensor on
the casing shoe.
BRIEF DESCRIPTION OF THE DRAWING
[0023] FIG. 1 is a cross-section view of a drilling operation.
[0024] FIG. 2 is a cross-section view of casing being inserted into
a well.
[0025] FIG. 3 is a perspective view of a section of casing
according to the present 25 invention.
[0026] FIG. 4 is a perspective view of a section of casing
according to the present invention during the cementing
operation.
[0027] FIG. 5 is a perspective view of a section of casing
according to the present invention.
[0028] FIG. 6 is a perspective view of a section of casing
according to the present invention after drilling has pierced the
end of the casing.
[0029] FIG. 7 is a block diagram of a system according to the
present invention.
[0030] FIG. 8 is a block diagram of a system according to the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] An apparatus for monitoring geological properties and
drilling parameters and for facilitating seismic while drilling
comprises sensors, actuators and generators coupled to the casing.
The sensors allow the collection and transmission to the surface of
geological data and critical drilling parameters (such as hydraulic
measurements downhole weight on bit, and downhole torque) from
shortly after the casing is inserted until the data is no longer
needed. The actuators and generators facilitate the collection of
data and are controllable from the surface. The apparatus also
provides a relay for data transmitted from deeper in the well bore
or from MWD or LWD tools. The equipment relays data between the
surface and the sensors, actuators and generators deep in the
well.
[0032] As shown in FIG. 1, a drilling rig 10 (simplified to exclude
items not important to this application) comprises a derrick 12,
derrick floor 14, draw works 16, hook 18, swivel 20, kelly joint
22, rotary table 24, drillstring 26, drill collar 28, LWD tool 30,
LWD tool 32 and drill bit 34. Mud is injected into the swivel by a
mud supply line 38. The mud travels through the kelly joint 22,
drillstring 26, drill collars 28, and LWD tools 30 and 32 and exits
through jets or nozzles in the drill bit 34. The mud then flows up
the borehole 40. A mud return line 42 returns mud from the borehole
40 and circulates it to a mud pit (not shown) and back to the mud
supply line 38. The combination of the drill collar 28, LWD tool
30, LWD tool 32 and drill bit 34 is known as the bottomhole
assembly 36 (or "BHA").
[0033] The data collected by the LWD tools 30 and 32 is returned to
the surface for analysis by, for example, telemetry transmitted
through the drilling mud. A telemetry transmitter 44 located in a
drill collar or in one of the LWD tools collects data from the LWD
tools and modulates the data to transmit it through the mud. A
telemetry sensor 46 on the surface detects the telemetry and
returns it to a demodulator 48. The demodulator 48 demodulates the
data and provides it to computing equipment 50 where the data is
analyzed to extract useful information.
[0034] After the well has been drilled to a certain depth, has
shown in FIG. 2, a length of casing 52 is lowered into the well
bore in sections. The first section 54, called a "casing shoe", has
a specialized purpose, as will be discussed below. As it is being
lowered, the section of casing is suspended from casing hangar 56,
which hangs from the hook 18.
[0035] When the casing 52 has been fully inserted into the
borehole, as shown in FIG. 3, the casing shoe 54 comes to rest at
or near the bottom of the well bore. A centralizer 58 keeps the
casing centered in the borehole. Signal-carrying cable 60 connects
a cable tie-in 62 to equipment on the surface. The cable 60 and
cable tie-in 62 allow a connection between the surface and sensors,
actuators and generators in the casing shoe, as will be discussed
below. Further, cable 60 provides connections between sensors,
actuators and generators located along the casing (not shown in
FIG. 3) to the casing shoe 54. Wireline anchor bands 64 secure the
cable 60 to the casing.
[0036] After the casing is position, it is cemented into place, as
shown in FIG. 4. Cement is pumped down through the casing to the
casing shoe where it escapes through port 66. The cement 68 flows
up the annulus between the casing and the surrounding formations
70.
[0037] When sufficient concrete has been poured to serve its
intended purpose, the concrete is allowed to set, as shown in FIG.
5. As concrete sets, its temperature varies. By monitoring the
temperature of the concrete using temperature sensor 72, personnel
at the surface can determine when the concrete has set sufficiently
to go into the next step in the drilling process. Information from
the temperature sensor 72 is transferred to the surface through
cable tie-in 62 and cable 60. Additional temperature sensors may be
placed at other locations to monitor the temperature of the
concrete.
[0038] The next step in the drilling process, shown in FIG. 6, is
to drill out casing 52. Drill bit 74 penetrates the end of casing
shoe 54 and continues the well bore. As drilling continues, mud is
pumped down through the center of the drillstring 76 and out jets
or nozzles in the drill bit 74. The mud 78 picks up cuttings and
carries them back to surface along the annulus between the drill
string and formation and then along the annulus between the
drillstring 76 and casing 52.
[0039] As discussed above, the specific gravity of the mud is
carefully controlled to assure that the pressure exerted by the mud
on the formation does not exceed the fracture pressure of
formation. The pressure exerted by the mud on the formation is
monitored by a pressure sensor 80 located in the casing shoe. Its
location in the casing shoe allows pressure sensor 80 to monitor
the pressure on the weakest formation just below the casing
shoe.
[0040] Personnel on the surface monitor the signals from the
pressure sensor, which are sent to the surface through the cable
tie-in 62 and cable 60. If they determine that the specific gravity
of the mud must be increased because of the danger of a "kick", or
influx of formation fluids into the borehole, and the planned
increase will raise the pressure exerted by the mud beyond the
fracture pressure of the formation, they may decide to stop
drilling and insert another section of casing.
[0041] In addition to the pressure sensor and temperature sensor
that were discussed above, additional sensors are located along the
casing to provide a variety of other functions. For example, an
array of acoustic sensors and/or geophones may be located along a
portion of the casing to receive acoustic energy from the formation
through the concrete surrounding the casing. Such acoustic sensors
could be used in conjunction with acoustic energy generators
located in the MWD tools for accomplishing MWD acoustic logging.
The acoustic energy generator could be attached to the casing,
allowing long term monitoring of the acoustic characteristics of
the formations surrounding the borehole. An acoustic energy
generator attached to the casing could also be used as a source for
acoustic energy measurements in- another nearby well.
[0042] Similarly, the acoustic sensors could be used to detect
acoustic energy generated by surface generators or by acoustic
sources in other nearby wells. The acoustic sensors could be used
during drilling and after the well is completed and is in
production or after it has been shut in.
[0043] Acoustic sensors coupled to the casing can also be used in
support of "look-ahead" technology, in which acoustic signals are
used to detect geological features ahead of the drill bit. With the
acoustic sensors coupled to the casing, the look-ahead performance
improves over a look-ahead system employing surface acoustic
sensors because the acoustic sensors coupled to the casing are
closer to the geological features being detected.
[0044] In addition to pressure sensors, temperature sensors and
acoustic sensors and generators, stress and strain sensors may be
located along the casing to measure the stress and strain to be
experienced by the formations surrounding the casing. Again, the
stress sensors and strain sensors can be used during drilling and
after the well has been completed and has been placed in production
or has been shut in.
[0045] In another application of sensors, two or more pressure
sensors could be strategically located at various depths along the
inside of the casing. Such an arrangement of pressure sensors could
detect the dynamic changes in pressure associated with a kick. For
example, detection of dropping pressure at successively shallower
pressure sensors could indicate that a gas kick has occurred.
Advance warning of such an event would allow personnel on the
surface to engage blowout preventers to reduce the chance of injury
to the surface equipment or personnel.
[0046] In general, any sensor that provides useful information
regarding the formations surrounding the well can be attached to
the casing. Further, any actuator or generator that produces useful
signals, energy or actions to be used in measuring the properties
of the formations or in monitoring the drilling process may also be
attached to the casing.
[0047] The placement of the sensors, actuators and generators is
illustrated in FIG. 7. The well shown in FIG. 7 includes a surface
casing 82, an intermediate casing 84, and a drill string 86. A set
of surface casing sensors, actuators and generators 88 is coupled
to the surface casing 82. A set of intermediate casing sensors,
actuators and generators 90 is coupled to the intermediate casing
84. Depending on their purpose, the sensors, actuators and
generators may be attached to the inside of the casing or the
outside of the casing. The sensors, actuators and generators may be
welded to the casing or attached by bands or through special
annular fittings that affix them to the inside or the outside of
the casing in such a way that they do not interrupt the flow of
fluids through or around the casing.
[0048] A set of MWD tool sensors, actuators and generators 92 is
coupled to the drill string 86. For example, if the MWD tool is an
acoustic-logging tool, it would include acoustic energy generators
(transmitters) and acoustic energy sensors (receivers). Other types
of tools would include other types of sensors and generators. The
MWD tool sensors, actuators and generators 92 may provide, for
example, the capability to change the position of an adjustable
gauge stabilizer or to change the bit nozzle size or to activate
any actuator attached to the drill string.
[0049] The sensors, actuators and generators communicate with the
surface in one or more of several ways. First, each sensor,
actuator or generator may have a cable connection to the surface.
For example, the surface casing sensors, actuators and generators
88 may communicate with surface equipment 94 via cable 96 and the
intermediate casing sensors, actuators and generators 90 may
communicate with the surface equipment 94 via cable 98.
Alternatively, some or all of the surface casing sensors, actuators
and generators 88 may communicate with a surface casing controller
100, coupled to the surface casing 82, which gathers data provided
by the surface casing sensors, formats it and communicates it to
the surface equipment 94 via cable 98. Surface equipment 94 may
transmit commands or other data to the surface casing sensors,
actuators and generators 88 directly or through the surface casing
controller 100.
[0050] Similarly, some or all of the intermediate casing sensors,
actuators and generators 90 may communicate with an intermediate
casing controller 102, coupled to the intermediate casing 84, which
gathers data provided by the intermediate casing sensors, formats
it and transmits it to the surface equipment 94. Surface equipment
94 may transmit commands or other data to the intermediate casing
sensors, actuators and generators 90 directly or through the
intermediate casing controller 102.
[0051] Cables 96 and 98 can be any kind of cable, including
electrical cable or optical fiber cable. Further, the information
carried by the cable can be sent using any information transmission
scheme, including baseband, modulated (amplitude modulation,
frequency modulation, phase modulation, pulse modulation or any
other modulation scheme), and multiplexed (time-division
multiplexed, frequency-division multiplexed or any other
multiplexing scheme, including the use of spread spectrum
techniques). Consequently, each sensor, actuator or generator may
communicate with the surface equipment via its own communication
media which is part of cables 96 and 98 or each set 88 and 90 may
share a communication media that is part of cables 96 and 98,
respectively. Further, cables 96 and 98 may be coupled to allow the
surface casing sensors, actuators and generators to share the use
of the communication medium formed by the combination of the two
cables 96 and 98.
[0052] Alternatively, communication between the surface casing
controller 100 and the surface equipment 94 may be by radio
frequency transmission or pulse telemetry transmission. In the case
of radio frequency transmission, an antenna 104 extends from the
surface casing controller 100 that allows radio frequency
communication between it and the surface equipment 94, which would
communicate the RF energy via an antenna 106. In the case of pulse
telemetry transmission, the surface casing controller 100 and the
surface equipment 94 each include a transducer 108 and 110 (see
FIG. 8), respectively, that convert data into acoustic pulses and
vice versa. The acoustic energy travels through the casing 82, the
mud or any other medium that will allow the transmission of
acoustic energy. The RF energy and the acoustic energy can be
modulated or multiplexed in any of the ways described above.
Further, the communication between the surface casing controller
100 and the surface equipment 94 may be done through a combination
of communication through the cable, through RF transmission and
through pulse telemetry.
[0053] Communication between the intermediate casing controller 102
and the surface equipment 94 can be by any of the methods described
above for the communication between the surface casing controller
100 and the surface equipment 94. An antenna 112 is coupled to the
intermediate casing controller 102 to allow RF communication. An
acoustic transducer 114 (see FIG. 8) is coupled to the intermediate
casing controller 102 to allow pulse telemetry communication.
Alternatively, the surface casing controller 100 can serve as a
relay between the intermediate casing controller 102 and the
surface equipment 94. In this situation, the intermediate casing
controller 102 communicates with the surface casing controller 100
using any of the communication techniques discussed above,
including communicating by cable, by RF transmission or by pulse
telemetry. The surface casing controller 100 communicates with the
surface equipment 94 as discussed above.
[0054] The MWD tool sensors, actuators and generators 92
communicate with the surface equipment 94 through a drill string
controller 116. The drill string controller 116 compiles data from
the MWD tool sensors, actuators and generators 92 and transmits the
data to the surface equipment 94. The surface equipment 94
transmits commands and other data to the MWD tool sensors,
actuators and generators 92 through the drill string controller
116. The communication between the surface equipment 94 and the
drill string controller 116 may be relayed through the intermediate
casing controller 102 and the surface casing controller 100.
Alternatively, the drill string controller 116 may only use one of
the surface casing controller 100 or the intermediate casing
controller 102 as a relay. The communication between the drill
string controller 116 and the surface equipment 94 may use any of
the information transmission schemes described above. An antenna
118 is coupled to the drill string controller 116 to allow RF
communication. An acoustic transducer 120 (see FIG. 8) is coupled
to the drill string controller 116 to allow pulse telemetry
communication.
[0055] FIG. 8 illustrates all of the communication paths possible
among the various sensors, actuators, generators, controllers and
surface equipment. In the preferred embodiment, the surface casing
sensors, actuators and generators 88 communicate with the surface
casing controller 100 which communicates with the surface equipment
94 over cable 96. Alternatively: (a) one or more of the surface
casing sensors, actuators and generators 88 may communicate
directly with the surface equipment 94, as indicated by dotted line
122; (b) communication between the surface casing controller 100
and the surface equipment 94 may be by RF signals using antennas
104 and 106 or by pulse telemetry using acoustic transducers 108
and 110.
[0056] In the preferred embodiment, the intermediate casing
sensors, actuators and generators communicate with the intermediate
casing controller 102 which communicates with the surface equipment
94 by RF signals using antennas 104 and 112 or by pulse telemetry
using acoustic transducers 108 and 114. Alternatively: (a) one or
more of the intermediate casing sensors, actuators and generators
90 may communicate directly with the surface equipment 94, as
indicated by dotted line 124; (b) communication between the
intermediate casing controller 102 and the surface equipment 94 may
be by way of cable 98 (shown as a dotted line).
[0057] In the preferred embodiment, the drill string sensors,
actuators and generators 92 communicate directly with the drill
string controller 116, which may be part of an MWD tool or some
other piece of drill string equipment. The drill string controller
116 communicates with the surface equipment 94 through antenna 118
and/or acoustic transducer 120 directly or using the intermediate
casing controller 102 and/or the surface casing controller 100 as
relays.
[0058] The foregoing describes preferred embodiments of the
invention and is given by way of example only. The invention is not
limited to any of the specific features described herein, but
includes all variations thereof within the scope of the appended
claims.
* * * * *