U.S. patent application number 10/878775 was filed with the patent office on 2005-12-29 for closed-loop drilling system using a high-speed communications network.
Invention is credited to Fox, Joe, Hall, David R..
Application Number | 20050284659 10/878775 |
Document ID | / |
Family ID | 35504377 |
Filed Date | 2005-12-29 |
United States Patent
Application |
20050284659 |
Kind Code |
A1 |
Hall, David R. ; et
al. |
December 29, 2005 |
Closed-loop drilling system using a high-speed communications
network
Abstract
A closed-loop downhole drilling system is disclosed that
includes a high-speed communications network, comprising multiple
nodes, integrated into a downhole drilling string. The high-speed
communications network supports data transmission rates far
exceeding data rates of mud pulse telemetry systems. Sensors,
located at a selected points along the downhole drilling string,
are operably connected to the nodes and transmit data through the
communications network corresponding to conditions sensed downhole.
A control module receives the sensor data through the
communications network and automatically adjusts uphole or
downhole-drilling parameters in response thereto.
Inventors: |
Hall, David R.; (Provo,
UT) ; Fox, Joe; (Spanish Fork, UT) |
Correspondence
Address: |
David R. Hall
2185 S. Larsen Pkwy
Provo
UT
84606
US
|
Family ID: |
35504377 |
Appl. No.: |
10/878775 |
Filed: |
June 28, 2004 |
Current U.S.
Class: |
175/27 |
Current CPC
Class: |
H04L 67/02 20130101;
E21B 47/12 20130101; H04L 67/025 20130101; H04L 67/12 20130101;
H04L 69/329 20130101; E21B 44/00 20130101 |
Class at
Publication: |
175/027 |
International
Class: |
E21B 003/06 |
Goverment Interests
[0001] This invention was made with government support under
Contract No. DE-FC26-01NT41229 awarded by the U.S. Department of
Energy. The government has certain rights in the invention.
Claims
What is claimed is:
1. A closed-loop downhole drilling system, the system comprising: a
downhole drilling string; a communications network comprising a
plurality of nodes spaced at selected intervals along the downhole
drilling string; a sensor, located at a selected point along the
downhole drilling string, configured to provide data corresponding
to conditions sensed downhole, the sensor being in operable
communication with the downhole communications network; and a
control module, in operable communication with the communications
network, configured to receive the data through the communications
network and automatically adjust at least one parameter of the
downhole drilling system in response to the data.
2. The system of claim 1, wherein the plurality of nodes are in
operable communication with one another.
3. The system of claim 1, wherein the sensor is selected from the
group consisting of a coring tool, a mud logging device, a flow
rate sensor, an RPM sensor, a torque sensor, a pore fluid sensor, a
permeability sensor, a density sensor, a resistivity sensor, an
induction sensor, a sonic device, a radioactivity sensor, a gamma
ray tool, an electrical potential tool, a vibration sensor, a
magnetic sensor, a Hall-effect sensor, a temperature sensor, an
accelerometer, an imaging device, a seismic device, a caliper tool,
a pressure sensor, an inclination sensor, an azimuth sensor, a
surveying tool, a navigation tool, an MWD tool, a DWD tool, a LWD
tool, a GPS device, a load sensor, a displacement sensor, a kick
detector, a fluid sampling device, and a tool-wear sensor.
4. The system of claim 1, wherein the at least one parameter is
selected from a downhole parameter and an uphole parameter.
5. The system of claim 4, wherein the downhole parameter is
selected from the group consisting of weight-on-bit, downhole motor
RPM, downhole motor torque, drilling direction, drilling fluid jet
direction, drilling fluid jet flow rate, drilling fluid flow rate,
drilling fluid rheology, drill jarring, kick control, and drilling
fluid pressure.
6. The system of claim 4, wherein the uphole parameter is selected
from the group consisting of weight-on-bit, drill string RPM, drill
string torque, kick control, drilling fluid flow rate, drilling
fluid rheology, and drilling fluid pressure.
7. The system of claim 1, wherein the control module is located
above the ground's surface.
8. The system of claim 1, wherein the control module is located
below the ground's surface.
9. The system of claim 1, wherein the communications network
supports a data transmission rate of at least 100 bits per
second.
10. The system of claim 1, wherein the data is raw data that is
processed above the ground's surface.
11. A method for implementing a closed-loop downhole drilling
system, the method comprising: providing a downhole drilling
string; placing a plurality of nodes at selected intervals along
the downhole drilling string, wherein the plurality of nodes are in
operable communication with one another; sensing a condition at a
selected point along the downhole drilling string; communicating
data corresponding to the condition by way of the plurality of
nodes; receiving the data from the plurality of nodes; and
automatically adjusting at least one parameter of the downhole
drilling string in response to the data.
12. The method of claim 11, wherein the condition is selected from
the group consisting of formation characteristics, drilling fluid
rheology, drill string RPM, drill string torque, acoustical
measurements, radioactivity, electrical potential, vibration,
magnetic field strength, Hall-effect, temperature, acceleration,
displacement, downhole dimensions, pressure, inclination, azimuth,
drill string position, load, downhole kicks, weight-on-bit, cutting
accumulations, fluid flow rates, and tool condition.
13. The method of claim 11, wherein the at least one parameter is
selected from a downhole parameter and an uphole parameter.
14. The method of claim 13, wherein the downhole parameter is
selected from the group consisting of weight-on-bit, downhole motor
RPM, downhole motor torque, drilling direction, drilling fluid jet
direction, drilling fluid jet flow rate, drilling fluid flow rate,
drilling fluid rheology, drill jarring, kick control, and drilling
fluid pressure.
15. The method of claim 13, wherein the uphole parameter is
selected from the group consisting of weight-on-bit, drill string
RPM, drill string torque, kick control, drilling fluid flow rate,
drilling fluid rheology, and drilling fluid pressure.
16. The method of claim 11, wherein automatically adjusting further
comprises adjusting the at least one parameter from above the
ground's surface.
17. The method of claim 11, wherein automatically adjusting further
comprises adjusting the at least one parameter from below the
ground's surface.
18. The method of claim 11, wherein communicating further comprises
communicating at a data transmission rate of at least 100 bits per
second.
19. The method of claim 11, further comprising processing the data
above the ground's surface.
20. A closed-loop downhole drilling system, the system comprising:
a downhole drilling string; a communications network comprising a
plurality of nodes spaced at selected intervals along the downhole
drilling string; a sensor, located at a selected point along the
downhole drilling string, configured to provide data corresponding
to conditions sensed downhole, the sensor being in operable
communication with the downhole communications network; and a
control module, in operable communication with the communications
network, configured to receive the data and automatically adjust at
least one parameter of the downhole drilling system in response to
the data.
Description
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to oil and gas drilling, and more
particularly to apparatus and methods for implementing a
closed-loop drilling system using a high-speed communications
network.
[0004] 2. Background
[0005] The goal of accessing data from a drill string has been
expressed for more than half a century. As exploration and drilling
technology has improved, this goal has become more important in the
industry for successful oil, gas, and geothermal well exploration
and production. For example, to take advantage of numerous advances
in the design of various tools and techniques for oil and gas
exploration, it would be beneficial to a drill operator to have
real time downhole data such as temperature, pressure, inclination,
salinity, etc., to optimize drilling parameters.
[0006] Various attempts have been made to devise a successful
high-speed system for accessing drill string data from downhole
components. However, due to the complexity, expense, and
unreliability of such systems, many such attempts have failed to
achieve significant commercial acceptance or implementation. As a
result, most drill operators continue to use very slow transmission
technologies by today's standards. For example, many drill
operators continue to use mud pulse telemetry to transmit data
between downhole sensors and the surface. In mud pulse telemetry
systems, data is transmitted by way of pressure pulses transmitted
through drilling fluid, such as drilling mud. Mud pulse telemetry
is often limited to data rates of 1 to 4 bits per second, which
creates severe limitations to the types and quantities of data that
can be transmitted uphole.
[0007] Due to these constraints, various drilling technologies
install data processing hardware downhole, near downhole tools and
sensors, to process data gathered therefrom. This raw data is
processed and condensed into "answers" or "conclusions" represented
by a relatively small number of data bits. These bits are then
transmitted uphole using mud pulse telemetry where an operator may
analyze the information and take responsive action. Nevertheless,
most raw data gathered from sensors and other downhole devices
cannot reach the surface due to the bottleneck created by mud pulse
telemetry. Moreover, the downhole environment may limit downhole
processors. For example, high temperatures, vibration, corrosive
elements, and the like, may limit the performance and
sophistication of downhole processors. In addition, slow data rates
of mud pulse telemetry systems may make reprogramming of downhole
circuitry very time consuming.
[0008] The bottleneck created by mud pulse telemetry and other
transmission systems may have other implications as well. For
example, various efforts have been directed to creating closed-loop
drilling systems that automatically adjust drilling parameters in
response to data gathered from downhole sensors. In general,
closed-loop systems use sensor feedback to adjust parameters
without manual input from an operator. The goal of closed-loop
drilling systems is to change drilling parameters rapidly and
dynamically in response to changing downhole conditions.
Closed-loop systems may be self-regulating, accurate, and reduce
the need for human supervision. This may reduce the expense of
operating a drill rig and the time needed to tap into oil and gas
bearing reservoirs.
[0009] Nevertheless, close-loop drilling systems are severely
limited by mud pulse or other telemetry systems. For example, due
to the limited bandwidth of current telemetry systems, control and
processing hardware is typically installed downhole near tools and
sensors. As was previously explained, control and processing
hardware may be limited in a downhole environment. Moreover,
closed-loop adjustments may be primarily limited to downhole
components, and significant amounts of data may not reach the
surface where it can be analyzed and logged to further optimize
drilling.
[0010] Thus, what are needed are apparatus and methods for
improving the performance and sophistication of closed-loop
drilling systems using a high-speed communications network.
[0011] What are further needed are apparatus and methods for
transmitting large amounts of data to the surface for logging,
analysis, and drilling parameter adjustments.
[0012] What are further needed are apparatus and methods for
relocating closed-loop controls and processing from downhole tools
to surface hardware.
SUMMARY OF THE INVENTION
[0013] In view of the foregoing, apparatus and methods in
accordance with the invention are directed to implementing a
closed-loop drilling system using a high-speed communications
network that significantly increased the performance and capability
of closed-loop systems. Apparatus and methods in accordance with
the invention are further directed transmitting large amounts of
data to the surface for logging, analysis, and use for adjusting
both uphole and downhole drilling parameters. Moreover, apparatus
and methods in accordance with the invention are directed to
relocating processing capability from downhole tools to the surface
where significantly greater processing power is available.
[0014] Consistent with the foregoing, and in accordance with the
invention as embodied and broadly described herein, a closed-loop
downhole drilling system is disclosed in one embodiment of the
present invention as including a high-speed communications network
integrated into a downhole drilling string. The high-speed
communications network supports data transmission rates far
exceeding traditional mud pulse telemetry systems. The
communications network includes multiple nodes installed at
selected intervals along the downhole drilling string. Sensors,
located at a selected point along the downhole drilling string, are
operably connected to the nodes and transmit data through the
communications network. A control module, in operable communication
with the communications network, receives the sensor data and
automatically adjusts uphole or downhole-drilling parameters in
response to the data.
[0015] Various different types of sensors may be used in making
drilling parameter adjustments. For example, in selected
embodiments, sensors may include formation coring tools, mud
logging devices, fluid flow rate sensors, RPM sensors, torque
sensors, pore fluid sensors, permeability sensors, density sensors,
resistivity sensors, induction sensors, sonic devices,
radioactivity sensors, gamma ray tools, electrical potential tools,
vibration sensors, magnetic field sensors, Hall-effect sensors,
temperature sensors, accelerometers, imaging devices, seismic
devices, caliper tools, pressure sensors, inclination sensors,
azimuth sensors, surveying tools, navigation tools, MWD tools, DWD
tools, LWD tools, GPS devices, load sensors, displacement sensors,
kick detection sensors, fluid sampling devices, tool-wear sensors,
or the like.
[0016] Data from these sensors may be used to optimize drilling
performance. For example, the control module may, in response to
the data, adjust or optimize various downhole drilling parameters
though the network including but not limited to weight-on-bit,
downhole motor RPM, downhole motor torque, drilling direction,
drilling fluid jet direction, drilling fluid jet flow rate,
drilling fluid flow rate, drilling fluid rheology, drill string
jarring, kick control devices, drilling fluid pressure, or the
like. Likewise, in other embodiments, the control module may adjust
or optimize various surface drilling parameters such as
weight-on-bit, drill string RPM, drill string torque, kick control,
drilling fluid flow rate, drilling fluid rheology, drilling fluid
pressure, or the like.
[0017] In selected embodiments, the control module is implemented
by electronic hardware and software located above the ground's
surface. In other embodiments, the control module may be integrated
into the drill string at a selected point below the ground's
surface, such as in the bottom hole assembly. Because of the
high-speed capability of the communications network, raw data from
any or all of the sensors located downhole may be transmitted
uphole where the data may be analyzed and processed. Thus, very
little data processing capability is needed downhole.
[0018] In another aspect of the invention, a method for
implementing a closed-loop downhole drilling system may include
installing multiple nodes at selected intervals along a downhole
drilling string, where each of the nodes are capable of high-speed
communication with one another. The method includes sensing
conditions at selected points along the downhole drilling and
communicating these conditions by way of data transmitted between
the high-speed nodes. These nodes may be capable of transmitting
data at speeds far exceeding data rates of traditional mud pulse
telemetry. The data may be received and used to automatically
adjust one or more uphole or downhole drilling parameters in
response thereto.
[0019] In selected embodiments, the data may contain information
corresponding to uphole or downhole conditions and measurements
such as formation characteristics, drilling fluid rheology, drill
string RPM, drill string torque, sonic measurements, radioactivity,
electrical potential, vibration, magnetic field strength,
Hall-effect field strength, temperature, acceleration, downhole
dimensions, pressure, inclination, azimuth, drill string position,
weight-on-bit, pressure kicks, fluid flow rates, tool conditions,
or the like.
[0020] Likewise, in response to these conditions, downhole
parameters may be automatically adjusted. These downhole parameters
may include weight-on-bit, downhole motor RPM, downhole motor
torque, drilling direction, drilling fluid jet direction, drilling
fluid jet flow rate, drilling fluid flow rate, drilling fluid
rheology, drill jarring, drilling fluid pressure, or the like.
Likewise, uphole parameters that may also be adjusted include
weight-on-bit, drill string RPM, drill string torque, kick control,
drilling fluid flow rate, drilling fluid rheology, drilling fluid
pressure, or the like.
[0021] In selected embodiments, the data may be processed or
analyzed above the ground's surface. Thus, very little data
processing capability is need below the ground's surface. In other
embodiments, some data and corresponding adjustments may be
processed below the ground's surface using control and processing
hardware integrated into the drill string.
[0022] It should be noted that the term "operable communication" is
meant to describe a network that can transmit data at a rate 1,000
bits per second. U.S. Pat. Nos. 6,670,880 and 6,717,501 are
examples of two systems that can transmit data at such rates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The foregoing and other features of the present invention
will become more fully apparent from the following description,
taken in conjunction with the accompanying drawings. Understanding
that these drawings depict only typical embodiments in accordance
with the invention and are, therefore, not to be considered
limiting of its scope, the invention will be described with
additional specificity and detail through use of the accompanying
drawings in which:
[0024] FIG. 1 is a profile view of one embodiment of a drill rig
and drill string in accordance with the invention;
[0025] FIG. 2 is a schematic diagram illustrating one embodiment of
a downhole network in accordance with the invention, integrated
into the drill string;
[0026] FIG. 3 is a schematic block diagram illustrating various
types of hardware and software modules that may be included in a
network node in accordance with the invention;
[0027] FIG. 4 is a schematic block diagram illustrating one
embodiment of a closed-loop drilling system disclosed in the prior
art;
[0028] FIG. 5 is a schematic block diagram illustrating one
embodiment of a closed-loop drilling system using a high-speed
communications network in accordance with the invention;
[0029] FIG. 6 is a schematic block diagram illustrating another
alternative embodiment of a closed-loop drilling system using a
high-speed communications network in accordance with the
invention;
[0030] FIG. 7 is a flow chart illustrating one embodiment of a
process used to implement a closed-loop drilling system in
accordance with the invention.
[0031] FIG. 8 is a schematic block diagram illustrating one
embodiment of a downhole network interfacing to various tools and
sensors;
[0032] FIG. 9 is a schematic block diagram illustrating one
embodiment of hardware and software components that may be included
in a network node in accordance with the invention; and
[0033] FIG. 10 is a schematic block diagram illustrating one
embodiment of a network packet in accordance with the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] It will be readily understood that the components of the
present invention, as generally described and illustrated in the
Figures herein, could be arranged and designed in a wide variety of
different configurations. Thus, the following more detailed
description of embodiments of apparatus and methods of the present
invention, as represented in the Figures, is not intended to limit
the scope of the invention, as claimed, but is merely
representative of various selected embodiments of the
invention.
[0035] The illustrated embodiments of the invention will be best
understood by reference to the drawings, wherein like parts are
designated by like numerals throughout. Those of ordinary skill in
the art will, of course, appreciate that various modifications to
the apparatus and methods described herein may easily be made
without departing from the essential characteristics of the
invention, as described in connection with the Figures. Thus, the
following description of the Figures is intended only by way of
example, and simply illustrates certain selected embodiments
consistent with the invention as claimed herein.
[0036] Many of the functional units described in this specification
have been labeled as modules, in order to more particularly
emphasize their implementation independence. For example, modules
may be implemented in software for execution by various types of
processors. An identified module of executable code may, for
instance, comprise one or more physical or logical blocks of
computer instructions that may, for instance, be organized as an
object, procedure, or function. Nevertheless, the executables of an
identified module need not be physically located together, but may
comprise disparate instructions stored in different locations
which, when joined logically together, comprise the module and
achieve the stated purpose for the module. For example, a module of
executable code could be a single instruction, or many
instructions, and may even be distributed over several different
code segments, among different programs, and across several memory
devices.
[0037] Modules may also be implemented in hardware as electronic
circuits comprising custom VLSI circuitry, off-the-shelf
semiconductors such as logic chips, transistors, or other discrete
components. A module may also be implemented in programmable
hardware devices such as field programmable gate arrays,
programmable array logic, programmable logic devices, or the like.
Similarly, operational data may be identified and illustrated
herein within modules, and may be embodied in any suitable form and
organized within any suitable type of data structure. The
operational data may be collected as a single data set, or may be
distributed over different locations including over different
storage devices, and may exist, at least partially, merely as
electronic signals on a system or network.
[0038] Referring to FIG. 1, a drill rig 10 may include a derrick 12
and a drill string 14 comprised of multiple sections of drill pipe
16 and other downhole tools. The drill string 14 is typically
rotated by the drill rig 10 to turn a drill bit 20 that is loaded
against the earth 19 to form a borehole 11. Rotation of the drill
bit 20 may alternately be provided by other downhole tools such as
drill motors, or drill turbines (not shown) located adjacent to the
drill bit 20.
[0039] A bottom-hole assembly 21 may include a drill bit 20,
sensors, and other downhole tools such as logging-while-drilling
("LWD") tools, measurement-while-drilling ("MWD") tools,
diagnostic-while-drilling ("DWD") tools, or the like. Other
downhole tools may include heavyweight drill pipe, drill collar,
stabilizers, hole openers, sub-assemblies, under-reamers, rotary
steerable systems, drilling jars, drilling shock absorbers, and the
like, which are all well known in the drilling industry.
[0040] While drilling, a drilling fluid is typically supplied under
pressure at the drill rig 10 through the drill string 14. The
drilling fluid typically flows downhole through the central bore of
the drill string 14 and then returns uphole to the drill rig 10
through the annulus 11. Pressurized drilling fluid is circulated
around the drill bit 20 to provide a flushing action to carry the
drilled earth cuttings to the surface.
[0041] Referring to FIG. 2, while continuing to refer generally to
FIG. 1, in selected embodiments, a downhole network 17 may be used
to transmit information along the drill string 14. The reader is
referred to U.S. Pat. Nos. 6,670,880 and 6,717,501 issued to Hall
et al., disclosing various embodiments of network hardware that can
be used to implement a network 17 in accordance with the invention.
These patents are herein incorporated by reference. The downhole
network 17 may include multiple nodes 18a-e spaced at desired
intervals along the drill string 14. The nodes 18a-e may be
intelligent computing devices 18a-e, such as routers, or may be
less intelligent connection devices, such as hubs, switches,
repeaters, or the like, located along the length of the network 17.
Each of the nodes 18 may or may not have a network address. A node
18e may be located at or near the bottom hole assembly 21. The
bottom hole assembly 21 may include a drill bit 20, drill collar,
and other downhole tools and sensors designed to gather data,
perform various functions, or the like.
[0042] Other intermediate nodes 18b-d may be located or spaced
along the network 17 to act as relay points for signals traveling
along the network 17 and to interface to various tools or sensors
located along the length of the drill string 14. Likewise, a
top-hole node 18a may be positioned at the top or proximate the top
of the drill string 14 to interface to an analysis device 28, such
as a personal computer.
[0043] Communication links 24a-d may be used to connect the nodes
18a-e to one another. The communication links 24a-d may consist of
cables or other transmission media integrated directly into the
tools comprising the drill string 14, routed through the central
bore of the drill string 14, or routed externally to the drill
string 14. Likewise, in certain embodiments, the communication
links 24a-d may be wireless connections. In selected embodiments,
the downhole network 17 may function as a packet-switched or
circuit-switched network.
[0044] To transmit data along the drill string 14, packets 22a, 22b
may be transmitted between the nodes 18a-e. The packets 22b may
carry data gathered by downhole tools or sensors to uphole nodes
18a, or may carry protocols or data necessary to the function of
the network 17. Likewise, some packets 22a may be transmitted from
uphole nodes 18a to downhole nodes 18b-e. For example, these
packets 22a may be used to carry control signals or programming
data from a top-hole node 18a to tools or sensors interfaced to
various downhole nodes 18b-e. Thus, a downhole network 17 may
provide a high-speed means for transmitting data and information
between downhole components and devices located at or near the
earth's surface 19.
[0045] Referring to FIG. 3, a network node 18 in accordance with
the invention may include a combination of hardware 29 and software
providing various functions 30. The functions 30 may be provided
strictly by the hardware 29, software executable on the hardware
29, or a combination thereof. For example, hardware 29 may include
one or several processors 31 capable of processing data as well as
executing instructions. The processor 31 or processors 31 may
include hardware such as busses, clocks, cache, or other supporting
hardware.
[0046] Likewise, the hardware 29 may include volatile 34 and
non-volatile 36 memories 32 to store data and provide staging areas
for data transmitted between hardware components 29. Volatile
memory 34 may include random access memory (RAM), or equivalents
thereof, providing high-speed memory storage. Memory 32 may also
include selected types of non-volatile memory 36 such as
read-only-memory (ROM), PROM, EEPROM, or the like, or other
long-term storage devices, such as hard drives, floppy disks, flash
memory, or the like. Ports 38 such as serial ports, parallel ports,
or the like may be used to interface to other devices connected to
the node 18, such as various sensors or tools located proximate the
node 18.
[0047] A modem 40 may be used to modulate digital data onto an
analog carrier signal for transmission over network cable or other
transmission media, and likewise, demodulate the analog signals
when received. A modem 40 may include various built in features
including but not limited to error checking, data compression, or
the like. In addition, the modem 40 may use any suitable modulation
type such as ASK, PSK, QPSK, OOK, CW, PCM, FSK, QAM, PAM, PPM, PDM,
PWM, or the like, to name a few. However, the choice of a
modulation type may depend on a desired data transmission speed,
the bandwidth capability of the network hardware, as well as unique
operating conditions that may exist in a downhole environment.
Likewise, the modem 40 may be configured to operate in full-duplex,
half-duplex, or other mode. The modem 40 may also use any of
numerous networking protocols currently available, such as
collision-based protocols like Ethernet, token-based, or
asynchronous transfer (ATM) protocols.
[0048] A node 18 may also include one or several switches 42, such
as multiplexers. A switch 42 may filter, forward, and route traffic
on the network. Multiplexers (and corresponding demultiplexers) may
transmit multiple signals over a single communications line or a
single channel. The multiplexers may use any known protocol to
transmit information over the network 17, including but not limited
to frequency-division multiplexing, time-division multiplexing,
statistical time-division multiplexing, wave-division multiplexing,
code-division multiplexing, spread spectrum multiplexing, or a
combination thereof.
[0049] A node 18 may also include various downhole tools 46 and
sensors 44. These tools 46 and sensors 44 may be integrated into
the node 18 (i.e. share the same circuitry) or interface to the
node 18 through ports 38. Tools 46 and sensors 44 may include
devices such as coring tools, mud logging devices, pore fluid
sensors, resistivity sensors, induction sensors, sonic devices,
radioactivity sensors, electrical potential tools, temperature
sensors, accelerometers, imaging devices, seismic devices,
mechanical devices such as caliper tools or free point indicators,
pressure sensors, inclinometers, surveying tools, navigation tools,
or the like. These tools 46 and sensors 44 may be configured to
gather data for analysis uphole, and may also receive data such as
control signals, programming data, or the like, from uphole
sources. For example, control signals originating at the surface
may direct a sensor 44 to take a desired measurement. Likewise,
selected tools 46 and sensors 44 may be re-programmed through the
network 17 without extracting the tools from the borehole.
[0050] A drill string 14 may extend into the earth 20,000 feet or
more. As such, signal loss or attenuation may be a significant
factor when transmitting data along the downhole network 17. This
signal loss or attenuation may vary according to the network
hardware. For example, a drill string 14 is typically comprised of
multiple segments of drill pipe 16 or other drill tools. As such,
signal loss may occur each time a signal is transmitted from one
downhole tool to another. Since a drill string may include several
hundred sections of drill pipe 16 or other tools, the aggregate
attenuation can be significant. Likewise, attenuation may also
occur in the cable or other transmission media routed along the
drill string 14.
[0051] To compensate for signal attenuation, repeaters 48, or
amplifiers, may be spaced at selected intervals along the network
17. The amplifiers may receive a data signal, amplify it, and
transmit it to the next node 18. Like amplifiers, repeaters 48 may
be used to receive a data signal and retransmit it at higher power.
However, unlike amplifiers, repeaters 48 may remove noise from the
data signal. This may be done by demodulating the data from the
transmitted signal and re-modulating it onto a new carrier.
[0052] Likewise, a node 18 may include various filters 50. Filters
50 may be used to filter out undesired noise, frequencies, and the
like that may be present or introduced into a data signal traveling
up or down the network 17. Likewise, the node 18 may include a
power supply 52 to supply power to any or all of the hardware 29.
The node 18 may also include other hardware 54, as needed, to
provide other desired functionality to the node 18.
[0053] The node 18 may provide various functions 30 that are
implemented by software, hardware, or a combination thereof. For
example, the node's functions 30 may include data gathering 56,
data processing 58, control 60, data storage 62, or other functions
64. Data may be gathered 56 from sensors 44 located downhole, tools
46, or other nodes 18 in communication with a selected node 18.
This data 56 may be transmitted or encapsulated within data packets
transmitted up and down the network 17.
[0054] Likewise, the node 18 may provide various data processing
functions 58. For example, data processing may include data
amplification or repeating 72, routing or switching 74 data packets
transmitted along the network 17, error checking 76 of data packets
transmitted along the network 17, filtering 78 of data, as well as
data compression 79 and decompression. Likewise, a node 18 may
process various control signals 60 transmitted from the surface to
tools 46, sensors 44, or other nodes 18 located downhole. Likewise,
a node 18 may store data that has been gathered from tools 46,
sensors 44, or other nodes 18 within the network 17. Likewise, the
node 18 may include other functions 64, as needed.
[0055] In selected embodiments, a node 18 may include a data rate
adjustment module 86. The data rate adjustment module 86 may
monitor network traffic traveling in both uphole and downhole
directions. The data rate adjustment module 86 may optimize the
network's settings and efficiency by adjusting the allocation of
bandwidth for data traveling uphole and downhole. As is typical in
most communication systems, data rates may be limited by the
available bandwidth of a particular system. For example, in
downhole drilling systems, available bandwidth may be limited by
the transmission cable, hardware used to communicate across tool
joints, electronic hardware in the nodes 18, the downhole
environment, or the like. Thus, the data rate adjustment module 86
may efficiently allocate the limited available bandwidth where it
is most needed.
[0056] For example, in selected embodiments, most of the network
traffic may flow from downhole tools 46 and sensors 44 to the
surface for analysis. Thus, ordinarily, most of the network
bandwidth may be allocated to traffic traveling uphole.
Nevertheless, in some circumstances, more bandwidth may be needed
for traffic traveling downhole. For example, in some cases,
significant downhole bandwidth may be needed when reprogramming
downhole tools 46 and sensors 44, or when sending large amounts of
control data downhole. In these instances, the data rate adjustment
module 86 may adjust the bandwidth to provide additional bandwidth
to downhole traffic. In some instances, this may include reducing
the allocated bandwidth for uphole traffic. Likewise, when the need
for additional downhole bandwidth has abated, the data rate
adjustment module 86 may readjust the available bandwidth by
re-allocating bandwidth to uphole traffic.
[0057] Referring to FIG. 4, as has been partially explained in the
background section of the present application, current telemetry
systems, such as mud pulse telemetry, create severe limitations
with respect to processing data gathered by downhole sensors,
adjusting drilling parameters in response to gathered data, and
communicating between downhole tools and sensors and surface
personnel and equipment. For example, as was previously explained,
various past and current technologies disclosed in the prior art
place data processing hardware downhole, near downhole tools and
sensors, to process data gathered from these tools and sensors. For
example, data processing or logging hardware 90 may be installed in
the bottom hole assembly 21 ("BHA") along with other downhole tools
46 and sensors 44. Nevertheless, because of the extremely slow data
rates of mud pulse telemetry, very little raw data is transmitted
uphole where it can be logged, analyzed, or used to adjust drilling
parameters. To the contrary, before data is transmitted to the
surface 19, raw data may be processed and condensed by downhole
hardware 90 into "answers" or "conclusions" represented by a
relatively small number of data bits. These bits may then be
transmitted 96 uphole by way of a pressure transducer 92 that
modulates digital data onto pressure pulses that travel up and down
the drill string. These pressure pulses may be demodulated at the
surface 19 where an operator may analyze the data and take action
in response thereto. Nevertheless, large amounts of valuable raw
data gathered from sensors and other downhole devices never reach
the surface 19, or at least are not transmitted to the surface 19
in real time.
[0058] Another problem with prior art systems is that processing
hardware 90 may be severely limited in the downhole environment.
For example, downhole processors 90 may be limited by conditions
such as high temperatures, vibration, corrosive elements, and the
like. Thus, processing hardware 90 that is usable in downhole
environments may be inferior to high-speed processors that are
available in modem day computers, workstations, and the like.
Therefore, the quantity and quality of data analysis that is
performed downhole may be significantly less than analysis that
could be performed at the surface 19, where more sophisticated and
higher-performance processing equipment may be available.
[0059] In addition, downhole processing hardware 90 may require
software or executable code to operate properly and to perform
desired tasks. This software or executable code may be modified by
reprogramming the hardware to alter or improve the functionality of
the hardware 90. Nevertheless, because of the slow downhole data
rates of current telemetry systems, such as mud pulse telemetry,
reprogramming may be very time-consuming. Thus, the inadequacy of
mud pulse telemetry may significantly slow down the downhole
drilling process, and limit the capability of downhole hardware
90.
[0060] Moreover, the slow data rates of mud pulse and other
telemetry systems may also affect the implementation of closed-loop
drilling systems. Closed-loop systems use feedback from downhole
sensors 46 and other devices to automatically adjust and optimize
drilling parameters without operator intervention. For example, a
closed-loop system may be used to monitor the position of the drill
bit 20 as it penetrates the formation. This position may be
compared to a target position that reflects the desired path of the
drill string 14. The closed-loop system may then automatically
adjust drilling parameters, such as drilling direction, by
adjusting downhole-drilling parameters to align the drill sting 14
with the target. This may be done by self-adjusting and without
human intervention.
[0061] Due to the speed and accuracy of modem-day processors,
compared to manual human input, drilling parameters may be adjusted
rapidly and accurately in response to changing downhole conditions.
Closed-loop systems may help to prevent or reduce undershooting,
overshooting, or inaccurate adjustments that are common when
manually changing drill string parameters. Moreover, closed-loop
drilling systems may require less supervision than manually
operated systems, thereby reducing the need for human intervention.
This may significantly reduce the expense of operating a drill rig
and can reduce the time needed to tap into oil and gas bearing
reservoirs.
[0062] Nevertheless, mud pulse telemetry severely limits the way
close-loop systems may be implemented in a drilling system. For
example, due to the limited bandwidth of mud pulse telemetry,
control circuitry 88 used to automatically adjust drill string
parameters is typically installed downhole near downhole sensors 44
and tools 46. In certain cases, some secondary control 94 may be
provided from the surface 19. For example, a secondary control
module 94 may be used to transmit minor control adjustments 98 to
the primary control module 88. In some case, these may simply be
manual adjustment made by a drill string operator.
[0063] Nevertheless, this secondary control module 94 may be
severely limited by the constraints imposed by mud pulse telemetry
and may play a minor part in the closed-loop drilling system. This
may be undesirable for several reasons. First, the speed and
sophistication of control circuitry may be significantly limited in
a downhole environment, as was previously explained. Second,
because control circuitry 88 is effectively isolated downhole,
closed-loop adjustments to drilling parameters may be primarily
limited to downhole tools and components. Third, significant data
that is used by the control circuitry 88 is not available at the
surface 19 for logging, analysis, or use to adjust drilling
parameters due to the slow data rates of mud pulse telemetry. Thus,
apparatus and methods are needed to overcome many of these
limitations.
[0064] Referring to FIG. 5, in selected embodiments, a closed-loop
drilling system in accordance with the invention may include tools
46 and sensors 44 installed in the bottom hole assembly 21 of a
drill string 14. Sensors 44 may be used to gather data and
measurements corresponding to downhole conditions. For example, in
selected embodiments, downhole tools 46 and sensors 44 may include
coring tools, mud logging devices, flow rate sensors, RPM sensors,
torque sensors, pore fluid sensors, permeability sensors, density
sensors, resistivity sensors, induction sensors, sonic devices,
radioactivity sensors, gamma ray tools, electrical potential tools,
vibration sensors, magnetic sensors, Hall-effect sensors,
temperature sensors, accelerometers, imaging devices, seismic
devices, caliper tools, pressure sensors, inclination sensors,
azimuth sensors, surveying tools, navigation tools, MWD tools, DWD
tools, LWD tools, GPS devices, load sensors, displacement sensors,
kick detection sensors, fluid sampling devices, tool-wear sensors,
or the like. The tools 46 and sensors 44 may communicate with one
or several high-speed network nodes 18e. Likewise, other high-speed
nodes 18b-d may be located at selected intervals along the drill
string. These nodes 18b-e may communicate with one another and
carry raw data 100 in real time from the tools 46 and sensors 44 to
the surface 19. Due to the large amount of rate 100 that may be
gathered by numerous tools 46 and sensors 44, the downhole network
17 must support a data rate far greater than that supported by mud
pulse telemetry.
[0065] Since raw data is available in real time at the surface 19,
a primary control module 88 and primary processing module 90 for
the closed-loop drilling system may be located at the surface 19.
The functionality of the control and processing modules 88, 90 may
be provided by hardware, software, or a combination thereof located
on computers, such as servers, workstation, personal computers, or
other computing devices located at the surface 19, near the
drilling rig 10, or at locations remote from the drill rig 10. As
was previously explained, because most of the control and data
processing functions are performed above the surface 19, more
sophisticated and higher performance computers and other hardware
may be used that would not be adaptable or usable in a downhole
environment. Likewise, control and processing functions that were
formerly performed downhole may be reduced or eliminated. Or in
other embodiments, control and processing circuitry that was
previously provided in downhole components may be greatly
supplemented or enhanced by the high-speed network 17 and surface
control and processing devices 88, 90.
[0066] The primary control module 88 may receive raw data 100 and
automatically adjust drilling parameters in response thereto.
Likewise a processing module 90 may be located at the surface 19 to
process the raw data 100 and extract important information
concerning downhole conditions. This processed data may also be
used by the control module 88 to adjust drilling parameters.
Because the functionality of the control module 88 is located
primarily at the surface 19, both uphole and downhole drilling
parameters may be effectively adjusted. For example, certain
drilling parameters, such as drill string RPM, torque, mud
rheology, mud pressure, and weight-on-bit, may be adjusted from the
surface 19, since these parameters are primarily changed by
adjusting surface drilling equipment.
[0067] Likewise, the control module 88 may also adjust
downhole-drilling parameters by communicating with downhole
equipment through the network 17. For example, the control module
88 may adjust downhole parameters such as downhole motor RPM,
torque, or weight-on-bit, or may adjust directional drilling tools
that steer the drill bit in a desired direction. Because of the
large bandwidth of the network 17, the network 17 may support large
amounts of control data 102 flowing downhole.
[0068] Referring to FIG. 6, in another embodiment, some control 94
and processing (not shown) capability may be retained downhole.
These control components 94 may communicate with control and
processing hardware 88, 90 at the surface 19 through the high-speed
network 17. In selected embodiments, downhole control hardware 94
may primarily control downhole drilling parameters, while surface
hardware 88, 90 may primarily control surface drilling parameters.
In the event that communication is lost between the surface 19 and
downhole equipment, the downhole control module 94 may continue to
operate by gathering data from downhole tools 46 and sensors 44 and
making adjustments to downhole operating parameters in response to
the data. Nevertheless, when uphole and downhole hardware
components 88, 90, 94 are communicating properly through the
network 17, most of the control and processing functionality 88, 90
may still be provided by hardware and software located above the
surface 19.
[0069] Referring to FIG. 7, a process 103 for implementing a
closed-loop drilling system in accordance with the invention may
include initially gathering 104 downhole data. As was previously
explained, this may be accomplished using any number of tools 46
and sensors 44 located downhole or above the surface 19. This data
may then be transmitted 106 over the downhole network 17. For
example, data from downhole tools 46 and sensors 44 may be
transmitted to surface control and processing hardware 88, 90 for
analysis via the network 17. Once received 108, the data may be
analyzed 110. In selected embodiments, data analysis 110 may
include analyzing the data to determine 111 downhole conditions or
comparing 112 the data to pre-determined targets. For example,
downhole conditions may be determined 111 by sensing differences in
mud pressure at different points along the drill string. These
pressure differences may indicate that accumulations of cuttings or
other debris may be blocking off the flow of mud and may be
increasing the chances of a stuck pipe. Likewise, navigation
sensors, such as GPS devices, may determine the current position of
the drill bit. This position may then be compared 112 with target
data to determine if the drill bit 20 is following a correct path
or if directional adjustments need to be made. The foregoing
examples are simply presented by way of example and are not
intended to limit the scope of the present invention.
[0070] Once the data is analyzed 110, responsive action may be
determined 113. For example, responsive action may include
adjusting 114 drilling parameters to optimize drilling, to correct
undesired conditions, to correct deviations from selected targets,
or the like. Drilling parameters may include both uphole parameters
115 and downhole parameters 116. Uphole parameters 115 may be
adjusted at the surface 19, whereas downhole parameters 116 may be
adjusted downhole through the network 17. Uphole parameters 115 may
include parameters such as weight-on-bit, drill string RPM, drill
string torque, kick control, drilling fluid flow rate, drilling
fluid rheology, drilling fluid pressure, or the like. Likewise,
downhole parameters may include parameters such as weight-on-bit,
downhole motor RPM, downhole motor torque, drilling direction,
drilling fluid jet direction, drilling fluid jet flow rate,
drilling fluid flow rate, drilling fluid rheology, drill jarring,
kick control, drilling fluid pressure, or the like.
[0071] Referring to FIG. 8, in one embodiment, a downhole network
17 in accordance with the invention may include a top-hole node 18a
and a bottom-hole node 18e. A bottom-hole node 18e may interface to
various components located in or proximate a bottom-hole assembly
21. For example, a bottom-hole node 18e may interface to a
temperature sensor 126, an accelerometer 128, a DWD
(diagnostic-while-drilling) tool 130, or other tools 46c or sensors
44c such as those listed in the description of FIG. 3.
[0072] A bottom-hole node 18e may communicate with an intermediate
node 18c located at an intermediate point along the drill string
14. The intermediate node 18c may also provide an interface to
tools 46b or sensors 44b communicating through the network 17.
Likewise, other nodes 18, such as a second intermediate node 18b,
may be located along the drill string 14 to communicate with other
sensors 44a or tools 46a. Any number of intermediate nodes 18b, 18c
may be used along the network 17 between the top-hole node 18a and
the bottom-hole node 18e.
[0073] In selected embodiments, a physical interface 122 may be
provided to connect network components to a drill string 14. For
example, since data may be transmitted directly up the drill string
on cables or other transmission media integrated directly into
drill pipe 16 or other drill string components, the physical
interface 122 may provide a physical connection to the drill string
so data may be routed off of the drill string 14 to network
components, such as a top-hole node 18a, or analysis device 28.
[0074] For example, a top-hole node 18a may be operably connected
to the physical interface 122. The top-hole node 18a may also be
connected to an analysis device 28 such as a personal computer. The
personal computer may be used to analyze or examine data gathered
from various downhole tools 46 or sensors 44. Likewise, tool and
sensor data 120a may be saved or output from the personal computer.
Likewise, in other embodiments, tool and sensor data may be
extracted directly from the top-hole node 18a for analysis.
[0075] Referring to FIG. 9, in selected embodiments, a node 18 may
include various components to provide desired functionality. For
example switches 42, multiplexers, or a combination thereof may be
used to receive, switch, and multiplex or demultiplex signals,
received from other uphole 140a and downhole 140b nodes 18. The
switches 42 or multiplexers may direct traffic such as data packets
or other signals into and out of the node 18, and may ensure that
the packets or signals are transmitted at proper time intervals,
frequencies, or combinations thereof.
[0076] In certain embodiments, the multiplexer may transmit several
signals simultaneously on different carrier frequencies. In other
embodiments, the multiplexer may coordinate the time-division
multiplexing of several signals. Signals or packets received by the
switch 42 or multiplexer may be amplified and filtered 50, such as
to remove noise. In certain embodiments received signals may simply
be amplified. In other embodiments, the signals may be received,
data may be demodulated therefrom and stored, and the data may be
remodulated and retransmitted on a selected carrier frequency
having greater signal strength. A modem 40 may be used to
demodulate digital data from signals received from the switch 42 or
multiplexer and modulate digital data onto carrier signals for
transfer to the switches 42 or multiplexer for transmission uphole
or downhole
[0077] The modem 40 may also perform various tasks such as
error-checking 76 and data compression. The modem 40 may also
communicate with a microcontroller 134. The microcontroller 134 may
execute any of numerous applications 136. For example, the
microcontroller 134 may run applications 136 whose primary function
is acquire data from one or a plurality of sensors 44a-c. For
example, the microcontroller 134 may interface to sensors 44 such
as inclinometers, thermocouplers, accelerometers, imaging devices,
seismic data gathering devices, or other sensors such as those
listed in the description of FIG. 3. Thus, the node 18 may include
circuitry to function as a data acquisition tool.
[0078] In other embodiments, the microcontroller 134 may run
applications 136 that may control various tools 46 or sensors 44
located downhole. That is, not only may the node 18 be used as a
repeater, and as a data gathering device, but may also be used to
receive or provide control signals to control selected tools 46 and
sensors 44 as needed. The node 18 may also include a volatile
memory device 34, such as a FIFO or RAM, that may be used to store
data needed by or transferred between the modem 40 and the
microcontroller 134.
[0079] Other components of the node 18 may include non-volatile
memory 36, which may be used to store data, such as configuration
settings, node addresses, system settings, and the like. One or
several clocks 132 may be provided to provide clock signals to the
modem 40, the microcontroller 134, or any other device. A power
supply 52 may receive power from an external power source 138 such
as batteries. The power supply 52 may provide power to any or all
of the components located within the node 18. Likewise, an RS232
port 38 may be used to provide a serial connection to the node
circuit 18.
[0080] Thus, the node 18 described in FIG. 6 may provide many more
functions than those supplied by a simple signal repeater. The node
18 may provide many of the advantages of an addressable node on a
local area network. The addressable node may amplify signals
received from uphole 140b or downhole 140a sources, be used as a
point of data acquisition, and be used to provide control signals
to desired sensors 44 or tools 46. These represent only a few
examples of the versatility of the node 18. Thus, the node 18,
although useful and functional as a repeater 30, may have a greatly
expanded capability.
[0081] Referring to FIG. 10, a packet 142 containing data, control
signals, network protocols, or the like may be transmitted up and
down the drill string 14 through the network 17. For example, in
one embodiment, a packet 142 in accordance with the invention may
include training marks 144. Training marks 144 may include any
overhead, synchronization, or other data needed to enable another
node 18 to receive a particular data packet 142.
[0082] Likewise, a packet 142 may include one or several
synchronization bytes 146. The synchronization byte 146 or bytes
146 may be used to synchronize the timing of a node 18 receiving a
packet 142. Likewise, a packet 142 may include a source address
148, identifying the logical or physical address of a transmitting
device, and a destination address 150, identifying the logical or
physical address of a destination node 18 on a network 17.
[0083] A packet 142 may also include a command byte 152 or bytes
152 to provide various commands to nodes 18 within the network 17.
For example, commands 152 may include commands to set selected
parameters, reset registers or other devices, read particular
registers, transfer data between registers, put devices in
particular modes, acquire status of devices, perform various
requests, and the like.
[0084] Likewise, a packet 142 may include data or information 154
with respect to the length 154 of data transmitted within the
packet 142. For example, the data length 154 may be the number of
bits or bytes of data carried within the packet 142. The packet 142
may then include data 156 comprising a number of bytes. The data
156 may include data gathered from various sensors 44 or tools 46
located downhole, or may contain control data to control various
sensors 44 or tools 46 located downhole. Likewise one or several
bytes 158 may be used to perform error checking of other data or
bytes within a packet 142. Trailing marks 160 may provide any other
overhead or synchronization needed after transmitting a packet 142.
One of ordinary skill in the art will recognize that network
packets 142 may take on many forms and contain varied information.
Thus, the example presented herein simply represents one
contemplated embodiment in accordance with the invention, and is
not intended to limit the scope of the invention.
[0085] The present invention may be embodied in other specific
forms without departing from its essence or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative, and not restrictive. The scope
of the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes within the
meaning and range of equivalency of the claims are to be embraced
within their scope.
* * * * *