WO2001059258A1 - A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system - Google Patents
A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system Download PDFInfo
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- WO2001059258A1 WO2001059258A1 PCT/EP2001/001512 EP0101512W WO0159258A1 WO 2001059258 A1 WO2001059258 A1 WO 2001059258A1 EP 0101512 W EP0101512 W EP 0101512W WO 0159258 A1 WO0159258 A1 WO 0159258A1
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- input signal
- modem
- piping structure
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- signal
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
- E21B43/122—Gas lift
- E21B43/123—Gas lift valves
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/003—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings with electrically conducting or insulating means
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/06—Valve arrangements for boreholes or wells in wells
- E21B34/066—Valve arrangements for boreholes or wells in wells electrically actuated
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/06—Valve arrangements for boreholes or wells in wells
- E21B34/08—Valve arrangements for boreholes or wells in wells responsive to flow or pressure of the fluid obtained
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/16—Control means therefor being outside the borehole
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/14—Obtaining from a multiple-zone well
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
- E21B47/13—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency
Definitions
- U.S. Patent No. 4,839,644 describes a method and system for wireless two-way communications in a cased borehole having a tubing string.
- this system describes a communication scheme for coupling electromagnetic energy in a TEM mode using the annulus between the casing and the tubing.
- This inductive coupling requires a substantially nonconductive fluid such as crude oil in the annulus between the casing and the tubing. Therefore, the invention described in U.S. Patent No. 4,839,644 has not been widely adopted as a practical scheme for downhole two-way communication.
- each sub-sea facility such as a wellhead, must have its own source of independent power.
- the power source is a battery pack for startup operations and a thermoelectric power generator for continued operations.
- 1 115 applies an electromagnetic VLF or ELF signal to the pipe comprising a voltage level oscillating about a DC voltage level.
- Figs. 18 and 19 and the accompanying text on pp. 40-42 does describe a crude system and method for getting downhole pressure and temperature measurements.
- the pressure and temperature sensors are passive (Bourdon and bi-metallic strip) where movement varies a circuit to provide resonant frequencies related to temperature and pressure. A frequency sweep at the wellhead looks for resonant spikes indicative of pressure and temperature.
- U.S. Patent No. 5,959,499 generally describes a method for determining a complex error signal and (during the operation mode of the system) generating a predistorted drive signal for a non-linear transmission path.
- U.S. Patent No. 5,963,090 generally describes a circuit applying non-linear characteristics to a signal.
- U.S. Patent No. 5,251,328 generally describes compensating for amplitude distortion in the communications channel by predistorting the amplitude of transmitted signals.
- 4,291,277 generally describes compensating for distortion introduced into a multiamplitude signal format by predistorting the input signals before they are subjected to non-linearities. The degree of predistortion may vary and is updated to reflect changes in the system.
- U.S. Patent No. 3,980,826 generally describes a method and means for transmitting a waveform of mixed frequency content over a transmission line to reduce the effects of transmitting digital signals over large distances.
- this lossy transmission medium One characteristic of this lossy transmission medium is that electromagnetic signals are attenuated at a rate proportional to the square root of the transmitted frequency. This frequency-dependent attenuation is called the "skin effect" resistance or impedance of the transmission line. This skin effect attenuation causes the edges of square wave pulses or general pulses with fast rise times to be smoothed or "smeared". As a result, it becomes increasingly difficult for the receiver detector to resolve and extract the information content of the original signal. Traditionally, to overcome this difficulty, either power must be increased or the data rate must be decreased so as to minimize the bit error rate and maximize the distance between transmitter- receiver pairs.
- the problems created by the skin effect resistance of a lossy transmission line are solved by predistorting an input signal that will be transmitted along the line.
- an optimal predistortion can be applied to the input signal before the signal is transmitted from the first location on the transmission line.
- the predistortion allows an output signal received at the second location on the transmission line to be substantially similar to a desired target signal.
- a communication system includes a pipe member with a first modem electrically connected to the pipe member at a first location.
- a second modem is electrically connected to the pipe member at a second location.
- a processor is provided for predistorting an input signal transmitted by the first modem to the pipe member.
- the second modem receives an output signal after the input signal is transmitted by the first modem.
- a measurement system for measuring an electrical formation characteristic for a petroleum well having a borehole and a piping structure that is located within the borehole.
- the measurement system includes a first modem electrically connected to the piping structure at a first location and a second modem electrically connected to the piping structure at a second location.
- the first modem imparts an input signal to the piping structure that is received as an output signal by the second modem.
- the electrical formation characteristic of the well can be derived.
- a method of communicating along a piping structure is also provided. The method is accomplished by predistorting an input signal and inputting the input signal onto the piping structure.
- the input signal is transmitted from a first location on the piping structure.
- An output signal is then received at a second location on the piping structure, the output signal being substantially similar to a desired target signal.
- FIG. 1 is a schematic front view of a petroleum well according to the present invention, the petroleum well having a tubing string and a casing positioned within a borehole.
- FIG. 2 is an electrical schematic of a communications system according to the present invention, the communications system being positioned within the borehole of the petroleum well of FIG. 1.
- FIG. 3A is an equivalent circuit diagram of a communications path on which the communications system of FIG. 2 transmits and receives signals.
- FIG. 3B is a schematic of an input signal being transmitted from a first location on a piping structure and being received as an output signal at a second location on the piping structure.
- FIG. 4 is a flowchart illustrating a method of predistorting a signal according to the present invention, the signal being predistorted prior to transmission along the communications path of FIG. 3.
- FIG. 5 is a vertical section schematic of an oil well having a measuring system according to the present invention, the well being completed in a multi-layer formation .
- FIG. 6 is a schematic of a pair of waveforms illustrating signal predistortion differences due to changing reservoir conditions. DESCRIPTION OF THE PREFERRED EMBODIMENTS
- a "piping structure" can be one single pipe, a tubing string, a well casing, a pumping rod, a series of interconnected pipes, rods, rails, trusses, lattices, supports, a branch or lateral extension of a well, a network of interconnected pipes, or other structures known to one of ordinary skill in the art.
- the preferred embodiment makes use of the invention in the context of an oil well where the piping structure comprises tubular, metallic, electrically-conductive pipe or tubing strings, but the invention is not so limited.
- at least a portion of the piping structure needs to be electrically conductive, such electrically conductive portion may be the entire piping structure (e.g.
- an electrically conductive piping structure is one that provides an electrical conducting path from one location where a power source is electrically connected to another location where a device and/or electrical return is electrically connected.
- the piping structure will typically be conventional round metal tubing, but the cross-sectional geometry of the piping structure, or any portion thereof, can vary in shape (e.g. round, rectangular, square, oval) and size (e.g. length, diameter, wall thickness) along any portion of the piping structure.
- valve is any device that functions to regulate the flow of a fluid.
- valves include, but are not limited to, bellows-type gas-lift valves and controllable gas-lift valves, each of which may be used to regulate the flow of lift gas into a tubing string of a well .
- the internal workings of valves can vary greatly, and in the present application, it is not intended to limit the valves described to any particular configuration, so long as the valve functions to regulate flow.
- Some of the various types of flow regulating mechanisms include, but are not limited to, ball valve configurations, needle valve configurations, gate valve configurations, and cage valve configurations.
- Valves can be mounted downhole in a well in many different ways, some of which include tubing conveyed mounting configurations, side-pocket mandrel configurations, or permanent mounting configurations such as mounting the valve in an enlarged tubing pod.
- modem is used generically herein to refer to any communications device for transmitting and/or receiving electrical communication signals via an electrical conductor (e.g. metal).
- the term is not limited to the acronym for a modulator (device that converts a voice or data signal into a form that can be transmitted) /demodulator (a device that recovers an original signal after it has modulated a high frequency carrier) .
- modem as used herein is not limited to conventional computer modems that convert digital signals to analog signals and vice versa (e.g. to send digital data signals over the analog Public Switched Telephone Network) . For example, if a sensor outputs measurements in an analog format, then such measurements may only need to be modulated (e.g.
- processor is used in the present application to denote any device that is capable of performing arithmetic and/or logic operations .
- the processor may optionally include a control unit, a memory unit, and an arithmetic and logic unit.
- sensor refers to any device that detects, determines, monitors, records, or otherwise senses the absolute value of or a change in a physical quantity. Sensors as described in the present application can be used to measure temperature, pressure (both absolute and differential), flow rate, seismic data, acoustic data, pH level, salinity levels, valve positions, or almost any other physical data .
- wireless means the absence of a conventional, insulated wire conductor e.g. extending from a downhole device to the surface. Using the tubing and/or casing as a conductor is considered “wireless”.
- Electronics module in the present application refers to a control device. Electronics modules can exist in many configurations and can be mounted downhole in many different ways. In one mounting configuration, the electronics module is actually located within a valve and provides control for the operation of a motor within the valve. Electronics modules can also be mounted external to any particular valve. Some electronics modules will be mounted within side pocket mandrels or enlarged tubing pockets, while others may be permanently attached to the tubing string. Electronics modules often are electrically connected to sensors and assist in relaying sensor information to the surface of the well. It is conceivable that the sensors associated with a particular electronics module may even be packaged within the electronics module.
- the electronics module is often closely associated with, and may actually contain, a modem for receiving, sending, and relaying communications from and to the surface of the well. Signals that are received from the surface by the electronics module are often used to effect changes within downhole controllable devices, such as valves. Signals sent or relayed to the surface by the electronics module generally contain information about downhole physical conditions supplied by the sensors. 1. Downhole Communication System
- the petroleum well is a gas-lift well 10 having a borehole 11 extending from a surface 12 into a production zone 14 that is located downhole.
- a production platform 20 is located at surface 12 and includes a hanger 22 for supporting a casing 24 and a tubing string 26.
- Casing 24 is of the type conventionally employed in the oil and gas industry.
- the casing 24 is typically installed in sections and is cemented in borehole 11 during well completion.
- Tubing string 26, also referred to as production tubing is generally conventional comprising a plurality of elongated tubular pipe sections joined by threaded couplings at each end of the pipe sections.
- Production platform 20 also includes a gas input throttle 30 to permit the input of compressed gas into an annular space 31 between casing 24 and tubing string 26.
- output valve 32 permits the expulsion of oil and gas bubbles from an interior of tubing string 26 during oil production.
- Gas-lift well 10 includes a communication system 34 for providing power and two-way communication downhole in well 10.
- Communication system 34 includes a lower ferromagnetic choke 42 that is installed on tubing string 26 to act as a series impedance to electric current flow. The size and material of ferromagnetic chokes 42 can be altered to vary the series impedance value.
- Hanger 22 includes an insulated portion 40 that electrically insulates tubing string 26 from casing 24 and from the remainder of the tubing string located above surface 12. The section of tubing string 26 between insulated portion 40 and lower choke 42 may be viewed as a power and communications path (see also FIGS. 2 and 3A) .
- Lower choke 42 is manufactured of high permeability magnetic material and is mounted concentric and external to tubing string 26. Choke 42 is typically hardened with injected epoxy to withstand rough handling.
- a computer and power source 44 having power and communication feeds 46 is disposed outside of borehole 11 at surface 12. Communication feeds 46 pass through a pressure feed 47 located in hanger 22 and are electrically coupled to tubing string 26 below insulated portion 40 of hanger 22. Power and communications signals are supplied to tubing string 26 from computer and power source 44.
- a plurality of downhole devices 50 is electrically coupled to tubing string 26 between insulated portion 40 and lower ferromagnetic choke 42. Some of the downhole devices 50 comprise controllable gas-lift valves. Other downhole devices 50 may comprise electronics modules, sensors, spread spectrum communication devices (i.e. modems), or conventional valves. Although power and communication transmission take place on the electrically isolated portion of the tubing string, downhole devices 50 may be mechanically coupled above or below lower choke 42.
- Communication system 34 includes all of the components required to communicate along tubing string 26 and casing 24.
- Two electronics modules 56 are connected to the tubing string 26 and the casing 24 downhole. Fewer or more electronics modules could be positioned downhole. Although electronics modules 56 appear identical, the modules 56 may contain or omit different components. A likely difference in each module could include a varying array of sensors for measuring downhole physical characteristics. It should also be noted that the electronics modules 56 may or may not be an integral part of a controllable valve.
- Each electronics module includes a power transformer 124 and a data transformer 128.
- a slave modem 130 is electrically coupled to data transformer 128 and is electrically connected to tubing string 26 and casing 24. Slave modem 130 communicates information to master modem 122 such as sensor information received from electronics module 56. Slave modem 130 receives information transmitted by master modem 122 such as instructions for controlling the valve position of downhole controllable valves. Additionally, each slave modem 130 is capable of communicating with other slave modems in order to relay signals or information .
- the present invention is directed to delivering signals along communication system 34 between a first modem and a second modem. It is important to note that the designation of "first modem” and “second modem” can be given to any of the modems previously mentioned (master modem 122 and slave modems 130) . More specifically, master modem 122 could be designated as the first modem and one of the slave modems 130 could be designated the second modem. An input signal is typically supplied by master modem 122 (the first modem) to tubing string 26. An output signal is received by slave modem 130 (the second modem) . An alternative designation could be to designate one of the slave modems 130 as the first modem and another slave modem 130 as the second modem.
- the transmission of sensor and control data up and down the well may require the relaying of signals between slave modems 130 rather than being passed directly between the surface and the selected downhole devices 50 (see FIG. 1) . Under these circumstances, communication would be taking place between the designated slave modems 130.
- the slave modems 130 are placed so that each can communicate with the next two slave modems up the well and the next two slave modems down the well. This redundancy allows communications to remain operational even in the event of the failure of one of the slave modems 130.
- a desired target signal is the signal that is intended to be received at the second modem.
- Each of the modems illustrated in FIG. 2 contains a processor 134 for determining a predistortion solution for each input signal .
- the amount and method of predistortion applied to the input signal is determined based on mathematical modeling of the communications path on which the input signal is transmitted. The mathematical treatment of this lossy communications path is detailed below. 2. Derivation of the Lossy Transmission Line Model Suppose that a single tubing string is suspended inside a fluid-filled casing using insulated packers and that the casing and tubing string are used as the two conductors for a transmission line.
- R total series resistance per unit length, shown at a resistor 140
- L total series inductance per unit length, shown at an inductor 142
- G shunt conductance per unit length, shown at a resistor 144
- the ratio of the voltage and current phasors give the characteristic impedance of the transmission line as
- T represents the signal velocity, as it propagates down the entire length of the transmission line.
- the transfer function g(t) may be derived by taking the inverse Laplace transform of the function f(p) ,
- an input signal is transmitted from a first location 148 on a piping structure 150 (e.g. tubing string or casing).
- the input signal is received as an output signal at a second location 151 on the piping structure 150.
- the input signal i.e. waveform
- Fj_ n (t) the input signal
- F ou ⁇ -(t) the resulting output signal
- a desired target signal i.e. waveform
- F in (t) co ⁇ o( ) + c ⁇ (t) + ••• + c N _ ⁇ N _ ⁇ (t)
- FoutW wo ⁇ o(t) + w ⁇ (t) + ••• + w N _ ⁇ N _ ⁇ (t)
- F target(t) tO ⁇ O ⁇ + ti$i(t) + ••• + t N _ ⁇ N _ ⁇ (t)
- the method and apparatus of the present invention broadly includes a means of compensating for the skin effect resistance of a transmission path by predistorting an emitted wave, or input signal, at a transmitting station on the transmission path so as to produce an output wave, or output signal at a receiver station that matches an actual desired target wave.
- the input signal is consciously distorted prior to transmission in such a way that the physics of the lossy transmission line constructively distorts the applied predistortion and results in a near-perfect replication of the input signal at the receiver station.
- the predistortion amount, or predistortion solution is obtained by developing a model for the skin effect resistance or attenuation caused by the transmission path. As previously described, this model is based on an equivalent circuit model for a tubing string suspended in a casing filled with completion fluid. After developing a model, a closed system control problem is formulated together with an iterative means of solving the control problem.
- the control problem has an optimal solution (i.e. a predistorted input signal) when the received output signal is a "best match", or is substantially similar to the desired target signal as measured by a least squares method.
- This iterative process defines the power-on negotiation process that must take place between communication station pairs so as to optimally determine the level of predistortion required to compensate for the skin effect attenuation.
- Other methods of developing such a model will be known to those of skill in the art, such as Artificial Neural Net and other AI solutions.
- FIG. 4 in the drawings the steps involved in optimally predistorting the input signal are illustrated. It should be noted that the actual selection and determination of the predistorted input signal is based on the mathematical solution to the control problem described previously. The first step,
- Determine Desired Target Signal 152 is performed prior to Predistort Input Signal 153.
- the desired target signal would be equal to the input signal transmitted and the output signal received.
- the input signal is predistorted to achieve an output signal that is substantially similar to the desired target signal.
- Predistort Input Signal 153 includes the following substeps: Select Waveform 154, Calculate Waveform 155, Apply Waveform 156, Select Power Level 158, Calculate Power Level 159, Apply Power Level 160, Select Center Frequency 162, Calculate Center Frequency 163, Apply Center Frequency 164, Select Chip Set 166, Calculate Chip Set 167, Apply Chip Set 168, Select Bandwidth 170, Calculate Bandwidth 171, and Apply
- Each of the "calculate” and “apply” steps is contingent on the successful determination of the related "select” step. For example, if a spread spectrum communication system is being used to transmit signals, a center frequency does not need to be selected. Instead, Select Chip Set 166 is answered affirmatively such that a chip set is calculated and applied by Calculate Chip Set 167 and Apply Chip Set 168. Alternatively, if an FSK- or PSK-modulated communication system is used, a chip set is not selected. Instead, Select Center Frequency 162 is answered affirmatively such that a center frequency is calculated and applied by Calculate Center Frequency 163 and Apply Center Frequency 164.
- the predistorted input signal is transmitted in accordance with Transmit Input Signal From First Location 174. This step is presumably performed by the first, or transmitting modem.
- the second, or receiving modem receives the output signal in accordance with Receive Output Signal at Second Location 176.
- the aforementioned optimal control solver will be implemented in a two-way modem in software and/or hardware form.
- the system first enters into a "tune-up" or calibration phase in which the optimal predistortion is determined at each location so as to maximize the data throughput and/or minimize the bit error rate.
- frequency pairs required to perform FSK (frequency shift keying) modulation or bandwidth/chipset configurations required to transmit data using a suitable spread-spectrum algorithm (such as CDMA) are optimally chosen.
- the communication architecture consists of multiple modem stations, multiple predistortion parameters may be derived for each source- receiver pair so that the entire communication infrastructure may operate at maximum efficiency.
- FIG. 5 in the drawings a measurement system 182 for characterizing the hydrocarbon saturation of a formation is illustrated.
- the casing and production tubing are used as the two conductors for a transmission line, analogous to a coaxial cable. If, on the other hand, the entire production tubing and casing are to be considered as a single conductor 184, a ground-return could be used to complete the electrical connection.
- the level of applied predistortion required for a source- receiver pair would yield the homogenized electrical properties for the formation between a source, or first modem 186 and a receiver, or second modem 188.
- These properties could include the per-unit-length conductance and capacitance and, thus, may be used to characterize the amount of hydrocarbon saturation in the formation outside of the well casing.
- Modems 188 are each positioned at a different station along the path of the well that penetrates several formation layers.
- a station 190 is positioned within Formation A
- a station 192 is positioned within Formation B
- a station 194 is positioned within Formation C.
- Each of the formation layers has measurable per-unit-length resistivity and dielectric properties that depend on the constituent rock composition, geological structure, fluid content (oil, water, gas), invaded fluid content and formation damage due to the presence of the well.
- transmission station 194 Upon initiating communication sessions with its nearest neighbors, transmission station 194 determines the optimum predistortion required to achieve a given data rate while minimizing the bit error rate. Using numerical analytical tools, such as finite element or finite difference analysis, phenomenological modeling of electromagnetic wave propagation in the subsurface may be conducted. These tools may be directed towards solving the "inverse problem" of deriving electrical formation characteristics - resistivity and dielectric permittivity - given signal predistortion differences in the input and the output signals.
- An example of reservoir monitoring using this invention is the tracking and positioning of oil-water contacts over the production lifetime of a field. At the beginning of a field's production life, sufficient oil is present in the reservoir to justify production.
- the initial oil-water contact at this point in time is OWC1. Since the electrical losses in the oil zone are surpressed by the presence of the fluidic insulator (oil), transceiver stations along a well inside the oil zone are able to transmit signals with minimal attenuation. Referring to FIG. 6 in the drawings, an example of the initial applied predistortion to a transmitted signal 196 is illustrated. However, after years of production, the produced oil and gas are replaced by water from the surrounding formation, resulting in a rise in the oil-water contact to OWC2.
- a new predistorted waveform 198 is also depicted in FIG. 6.
- the present invention can be applied in many areas where there is a need to provide a communication system within a borehole, well, or any other area that is difficult to access. Also, one skilled in the art will see that the present invention can be applied in many areas where there is an already existing conductive piping structure and a need to route power and communications to a location on the piping structure.
- a water sprinkler system or network in a building for extinguishing fires is an example of a piping structure that may be already existing and may have a same or similar path as that desired for routing power and communications. In such case another piping structure or another portion of the same piping structure may be used as the electrical return.
- the steel structure of a building may also be used as a piping structure and/or electrical return for transmitting power and communications in accordance with the present invention.
- the steel rebar in a concrete dam or a street may be used as a piping structure and/or electrical return for transmitting power and communications in accordance with the present invention.
- the transmission lines and network of piping between wells or across large stretches of land may be used as a piping structure and/or electrical return for transmitting power and communications in accordance with the present invention.
- Surface refinery production pipe networks may be used as a piping structure and/or electrical return for transmitting power and communications in accordance with the present invention.
- Appendix A contains source code and optimal predistortion solutions required to transmit 100, 500 and 2000 Mbit/second down a 100 meter piece of standard Black Box Plenum Ethernet coaxial cable.
- Graphs whose titles begin with "Control” describe the time-varying predistorted pulse function to be transmitted at the source end of the transmission line.
- Graphs whose titles begin with "Target and Output” describe the desired target signal (solid line) and the received output signal (dashed line) . As can be seen from the graphs, the received output signals match well the desired target signal.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2001237374A AU2001237374A1 (en) | 2000-02-09 | 2001-02-09 | A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system |
GB0218181A GB2376965B (en) | 2000-02-09 | 2001-02-09 | A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system |
CA002399130A CA2399130C (en) | 2000-02-09 | 2001-02-09 | A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18132200P | 2000-02-09 | 2000-02-09 | |
US60/181,322 | 2000-02-09 |
Publications (1)
Publication Number | Publication Date |
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WO2001059258A1 true WO2001059258A1 (en) | 2001-08-16 |
Family
ID=22663794
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2001/001512 WO2001059258A1 (en) | 2000-02-09 | 2001-02-09 | A method and apparatus for the optimal predistortion of an electromagnetic signal in a downhole communication system |
Country Status (4)
Country | Link |
---|---|
AU (1) | AU2001237374A1 (en) |
CA (1) | CA2399130C (en) |
GB (1) | GB2376965B (en) |
WO (1) | WO2001059258A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9303507B2 (en) | 2013-01-31 | 2016-04-05 | Saudi Arabian Oil Company | Down hole wireless data and power transmission system |
CN117052380A (en) * | 2023-10-10 | 2023-11-14 | 四川宏大安全技术服务有限公司 | Wireless pressure measurement device and method |
Citations (5)
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US4648471A (en) * | 1983-11-02 | 1987-03-10 | Schlumberger Technology Corporation | Control system for borehole tools |
EP0295178A2 (en) * | 1987-06-10 | 1988-12-14 | Schlumberger Limited | System and method for communicating signals in a cased borehole having tubing |
EP0492856A2 (en) * | 1990-12-20 | 1992-07-01 | AT&T Corp. | Predistortion technique for communications systems |
US5160925A (en) * | 1991-04-17 | 1992-11-03 | Smith International, Inc. | Short hop communication link for downhole mwd system |
US5959499A (en) * | 1997-09-30 | 1999-09-28 | Motorola, Inc. | Predistortion system and method using analog feedback loop for look-up table training |
-
2001
- 2001-02-09 WO PCT/EP2001/001512 patent/WO2001059258A1/en active IP Right Grant
- 2001-02-09 CA CA002399130A patent/CA2399130C/en not_active Expired - Fee Related
- 2001-02-09 AU AU2001237374A patent/AU2001237374A1/en not_active Abandoned
- 2001-02-09 GB GB0218181A patent/GB2376965B/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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US4648471A (en) * | 1983-11-02 | 1987-03-10 | Schlumberger Technology Corporation | Control system for borehole tools |
EP0295178A2 (en) * | 1987-06-10 | 1988-12-14 | Schlumberger Limited | System and method for communicating signals in a cased borehole having tubing |
EP0492856A2 (en) * | 1990-12-20 | 1992-07-01 | AT&T Corp. | Predistortion technique for communications systems |
US5160925A (en) * | 1991-04-17 | 1992-11-03 | Smith International, Inc. | Short hop communication link for downhole mwd system |
US5160925C1 (en) * | 1991-04-17 | 2001-03-06 | Halliburton Co | Short hop communication link for downhole mwd system |
US5959499A (en) * | 1997-09-30 | 1999-09-28 | Motorola, Inc. | Predistortion system and method using analog feedback loop for look-up table training |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9303507B2 (en) | 2013-01-31 | 2016-04-05 | Saudi Arabian Oil Company | Down hole wireless data and power transmission system |
CN117052380A (en) * | 2023-10-10 | 2023-11-14 | 四川宏大安全技术服务有限公司 | Wireless pressure measurement device and method |
CN117052380B (en) * | 2023-10-10 | 2024-01-02 | 四川宏大安全技术服务有限公司 | Wireless pressure measurement device and method |
Also Published As
Publication number | Publication date |
---|---|
AU2001237374A1 (en) | 2001-08-20 |
CA2399130A1 (en) | 2001-08-16 |
GB2376965A (en) | 2002-12-31 |
GB2376965B (en) | 2004-02-18 |
CA2399130C (en) | 2009-06-02 |
GB0218181D0 (en) | 2002-09-11 |
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