Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/12—Packers; Plugs
  • E21B33/129—Packers; Plugs with mechanical slips for hooking into the casing
  • E21B33/1294—Packers; Plugs with mechanical slips for hooking into the casing characterised by a valve, e.g. a by-pass valve
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK 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

• the present invention relates to a controllable production well packer.
• a petroleum production well packer comprising an electrically powered device, in which the device may comprise an electrically controllable valve, a communications and control module, a sensor, a modem, a tracer injection module, or any combination thereof.
• Petroleum wells typically pass through formations containing multiple zones that may produce differing fluids, as well as impermeable zones.
• the fluid-bearing zones may produce saline or clear water, oil, gas, or a mixture of these components.
• FIG. 1 A typical hydraulically set production packer of the prior art is schematically shown in FIG. 1.
• Packers are mechanical devices that close the annulus between the production tubing and the casing, and seal to both.
• Packers are typically installed at the time of well. completion by attaching them to a tubing string as it is lowered into the well. Thus, during placement, the packer must pass freely within the casing.
• a hydraulic actuator energized and controlled from the surface
• operates the sealing mechanism of the packer operates the sealing mechanism of the packer, which clamps the packer to the casing and effects a fluid-tight seal in the annular space between the tubing and the casing.
• Packers may provide complete isolation between the annular spaces above and below them, or may be equipped with one or more preset mechanically-actuated valves to control flow past them.
• control valves When control valves are included, however, their settings can only be altered by mechanically inserting a slick-line tool, which is inconvenient, slow, and relatively costly. Additionally, when there are multiple zones and multiple packers it is often impossible or impractical to reach the lowermost packers with a slick-line tool. This lack of a fast and inexpensive method for controlling valves in a packer is a constraint on well design and production operations.
• a packer adapted for use in a petroleum well wherein the packer comprises an electrically powered device
• the electrically powered device may comprise an electrically controllable valve adapted to control fluid communication from one side of the packer to another side of the packer when the packer is operably installed.
• the electrically powered device may further comprise a communications and control module being electrically connected to the electrically controllable valve, wherein the module comprises a modem adapted to receive control commands encoded within communication signals.
• the module can be adapted to decode the control commands received by the modem and control the movement of the valve using the control commands when the packer is operably installed.
• the electrically powered device may comprise a sensor adapted to detect at least one physical characteristic of a surrounding environment and generate data corresponding to the physical characteristic, as well as a modem adapted to receive the data from the sensor and electrically transmit the data in the form of an electrical communication signal.
• the electrically powered device can comprise an electrically controllable valve, a sensor, a modem, a communications and control module, a tracer injection module, or any combination thereof.
• a petroleum production well incorporating the packer described above.
• the petroleum well comprises a piping structure, a source of time- varying current, an electrical return, an induction choke, and the packer.
• the piping structure of the well comprises an electrically conductive portion extending along at least part of the piping structure.
• the piping structure can comprise a production tubing string of the well.
• the source of time- varying current comprises two source terminals. A first of the source terminals is electrically connected to the electrically conductive portion of the piping structure.
• the electrical return electrically connects between the electrically conductive portion of the piping structure and a second of the source terminals of the time- varying current source.
• the electrical return can comprise a well casing of the well, part of the packer, another packer, and/or a conductive fluid within the well.
• the induction choke is located about part of the electrically conductive portion of the piping structure at a location along the piping structure between the electrical connection location for the first source terminal and the electrical connection location for the electrical return, such that a voltage potential is formed between the electrically conductive portion of the piping structure on a source-side of the induction choke, and the electrically conductive portion of the piping structure on an electrical-return-side of the induction choke as well as the electrical return when time- varying current flows through the electrically conductive portion of the piping structure.
• the induction choke can comprise a ferromagnetic material.
• the induction choke need not be powered when its size, geometry, and magnetic properties can provide sufficient magnetic inductance for developing the voltage potential desired.
• the electrically powered device of the packer is electrically connected across the voltage potential such that part of the time- varying current is routed through the device due to the induction choke when the time-varying current flows through the electrically conductive portion of the piping structure.
• a method of producing petroleum products from a petroleum well comprising an electrically powered packer is provided.
• a conventional petroleum well includes a cased wellbore having a tubing string positioned within and longitudinally extending within the casing.
• a controllable packer is coupled to the tubing to provide a seal of the annular space between the tubing and casing.
• a valve in the packer (and/or other devices, such as sensors) is powered and controlled from the surface. Communication signals and power are sent from the surface using the tubing and casing as conductors.
• At least one induction choke is coupled about the tubing downhole to magnetically inhibit alternating current flow through the tubing at a choke.
• An insulating tubing joint, another induction choke, or another insulating means between the tubing and casing can be located at the surface above a location where current and communication signals are imparted to the tubing. Hence, most of the alternating current is contained between the downhole choke and the insulating tubing joint, or between the chokes when two chokes are used.
• a preferred embodiment utilizes the production tubing and the well casing as the electrical conduction path between the surface and downhole equipment.
• controllable packer in accordance with the present invention may incorporate sensors, with data from the sensors being received in real time at the surface.
• electrically motorized mechanical components such as flow control valves
• packer flow control valves the control of such components in the controllable packer hereof is near real time, allowing packer flow control valves to be opened, closed, adjusted, or throttled constantly to contribute to the management of production.
• a surface computer having a master modem can impart a communication signal to the tubing, and the communication signal is received at a slave modem downhole, which is electrically connected to or within the controllable packer.
• the communication signal can be received by the slave modem either directly or indirectly via one or more relay modems.
• electric power can be input into the tubing string and received downhole to power the operation of sensors or other devices in the controllable packer.
• the casing is used as a conductor for the electrical return.
• a controllable valve in the packer regulates the fluid communication in the annulus between the casing and tubing.
• the electrical return path 5 can be provided along part of the controllable packer, and preferably by the expansion of the expansion slips into contact with the casing.
• the electrical return path may be via a conductive centralizer around the tubing which is insulated in its contact with the tubing, but is in electrical contact with the casing and electrically connected to the device in the packer.
• controllable packer includes one or more sensors downhole which are preferably in contact with the downhole modem and communicate with the surface computer via the tubing and/or well casing.
• sensors as temperature, pressure, acoustic, valve position, flow rates, and differential pressure gauges can be advantageously used in many situations.
• the sensors supply
• ferromagnetic induction chokes are coupled about the tubing - to act as a series impedance to current flow on the tubing.
• an uppermost ferromagnetic induction chokes are coupled about the tubing - to act as a series impedance to current flow on the tubing.
• ferromagnetic choke is placed around the tubing below the casing' hanger, and the current and communication signals are imparted to the tubing below the upper ferromagnetic choke.
• a lower ferromagnetic choke is placed downhole around the tubing with the controllable packer electrically coupled to the tubing above the lower ferromagnetic choke, although the controllable packer may be mechanically coupled to the tubing 25 below the lower ferromagnetic choke instead.
• a surface computer is coupled via a surface master modem and the tubing to the downhole slave modem of the controllable packer.
• the surface computer can receive measurements from a variety of sources (e.g., downhole sensors), measurements of the oil output from the well, and measurements of the compressed gas 30 input to the well in the case of a gas lift well. Using such measurements, the computer can compute desired positions of the controllable valve in the packer, and more particularly, the optimum amount of fluid communication to permit into the annulus inside the casing.
• Construction of such a petroleum well is designed to be as similar to conventional 35 construction methodology as possible. That is, after casing the well, a packer is typically set to isolate each zone. In a production well, there may be several oil producing zones, water producing zones, impermeable zones, and thief zones. It is desirable to prevent or permit communication between the zones.
• the tubing string is fed through the casing into communication with the production zone, with controllable packers defining the production zone. As the tubing string is made up at the surface, a lower ferromagnetic choke is placed around one of the conventional tubing strings for positioning above the lowermost controllable packer.
• Controllable gas lift valves or sensor pods also may be coupled to the tubing as desired by insertion in a side pocket mandrel (tubing conveyed) and corresponding induction chokes as needed.
• the tubing string is made up to the surface where an upper ferromagnetic induction choke is again placed around the tubing string below the casing hanger. Communication and power leads are then connected to the tubing string below the upper choke.
• an electrically insulating joint is used instead of the upper induction choke.
• a sensor and communication pod can be incorporated into the controllable packer of the present invention without the necessity of including a controllable valve or other * control device. That is, an electronics module having pressure, temperature or acoustic sensors, power supply, and a modem can be incorporated into the packer for communication to the surface computer using the tubing and casing as conductors.
• FIG. 1 is a schematic showing a typical packer of the prior art
• FIG. 2 is a schematic showing a petroleum production well in accordance with a preferred embodiment of the present invention.
• FIG. 3 is a simplified electrical schematic of the embodiment shown in FIG. 2; and FIG. 4 is an enlarged schematic showing a controllable packer, from FIG. 2, comprising an electrically controllable valve.
• 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 similar structures known to one of ordinary skill in the art. ;
• the preferred embodiment makes use of the invention in the context of a petroleum well where the piping structure comprises tubular, metallic, electrically-conductive pipe or tubing strings, but the invention is not so limited.
• an electrically conductive piping structure is one that provides an electrical conducting path from a first portion where a power source is electrically connected to a second portion where a device and/or electrical return is electrically connected.
• the piping structure will typically be conventional round metal tubing, but the cross-section 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.
• a piping structure must have an electrically conductive portion extending from a first portion of the piping structure to a second portion of the piping structure, wherein the first portion is distally spaced from the second portion along the piping structure.
• first portion and second portion are each defined generally to call out a portion, section, or region of a piping structure that may or may not extend along the piping structure, that can be located at any chosen place along the piping structure, and that may or may not encompass the most proximate ends of the piping structure.
• the descriptors "upper”, “lower”, “uphole” and “downhole” are relative and refer to distance along hole depth from the surface, which in deviated or horizontal wells may or may not accord with vertical elevation measured with respect to a survey datum.
• modem is used herein to generically refer to any communications device for transmitting and/or receiving electrical communication signals via an electrical conductor (e.g., metal).
• modem as used . herein 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).
• modern 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).
• a sensor outputs measurements in an analog format
• measurements may only need to be modulated (e.g., spread spectrum modulation) and transmitted— hence no analog/digital conversion needed.
• a relay/slave modem or communication device may only need to identify, filter, amplify, and/or retransmit a signal received.
• valve 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.”
• the term “valve” as used herein generally refers to any device that functions to regulate the flow of a fluid. Examples of 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. The methods of installation for valves discussed in the present application can vary widely.
• electrically controllable valve generally refers to a “valve” (as just described) that can be opened, closed, adjusted, altered, or throttled continuously in response to an electrical control signal (e.g., signal from a surface computer or from a downhole electronic controller module).
• an electrical control signal e.g., signal from a surface computer or from a downhole electronic controller module.
• the mechanism that actually moves the valve position can comprise, but is not limited to: an electric motor; an electric servo; an electric solenoid; an electric switch; a hydraulic actuator controlled by at least one electrical servo, electrical motor, electrical switch, electric solenoid, or combinations thereof; a pneumatic actuator controlled by at least one electrical servo, electrical motor, electrical switch, electric solenoid, or combinations thereof; or a spring biased device in combination with at least one electrical servo, electrical motor, electrical switch, electric solenoid, or combinations thereof.
• An "electrically controllable valve” may or may not include a position feedback sensor for providing a feedback signal corresponding to the actual position of the valve.
• sensor refers to any device that detects, determines, monitors, records, or otherwise senses the absolute value of or a change in a physical quantity.
• a sensor as described herein can be used to measure physical quantities including, but not limited to: temperature, pressure (both absolute and differential), flow rate, seismic data, acoustic data, pH level, salinity levels, valve positions, or almost any other physical data.
• FIG. 1 is a schematic showing a conventional hydraulically set production packer 20 of the prior art set within a well casing 22 of a well.
• the packer 20 of FIG. 1 is threaded to a production tubing string 24.
• the conventional packer 20 has a tail piece 26 that may terminate with an open or closed end for the lowest packer in the completed well, or the tail piece 26 may be threaded onto tubing (not shown) that passes to lower regions of the well.
• the conventional packer 20 has a section of slips 28 and a seal section 30. Both the slips 28 and the seal section 30 can pass freely inside the well casing 22 during placement, and are operated by a hydraulic actuator 32.
• the hydraulic actuator 32 When the packer 20 is at its final location in the casing 22, the hydraulic actuator 32 is used to exert mechanical forces on the slips 28 and the seals 30 causing them to expand against the casing.
• the slips 28 lock the packer 20 in place by gripping the internal surface of the casing 22 so that the packer cannot be displaced by differential pressure between the spaces above and below the packer.
• the seal section 30 creates a liquid-tight seal between the spaces above and below the packer 20.
• the hydraulic actuator 32 is operated using high-pressure oil supplied from the surface (not shown) by a control tube 34.
• the conventional packer 20 does not comprise an electrically powered device.
• FIG. 2 is a schematic showing a petroleum production well 38 in accordance with a preferred embodiment of the present invention.
• the petroleum production well 38 shown in FIG. 2 is similar to a conventional well in construction, but with the incorporation of the present invention.
• a packer 40 comprising an electrically powered device 42 is placed in the well 3.8 in the same manner as a conventional packer 20 would be — to separate zones in a formation.
• the electrically powered device 42 of the packer 40 comprises an electrically controllable valve 44 that acts as a bypass valve, as shown in more detail in FIG. 4 and described further below.
• the piping structure comprises part of a production tubing string 24, and the electrical return comprises part of a well casing 22.
• An insulating tubing joint 146 and a ferromagnetic induction choke 48 are used in this preferred embodiment.
• the insulating joint 146 is incorporated close to the wellhead to electrically insulate the lower sections of tubing 24 from casing 22.
• the insulating joint 146 prevents an electrical short-circuit between the lower sections of tubing 24 and casing 22 at the tubing hanger 46.
• the hanger 46 provides mechanical coupling and support of the tubing 24 by transferring the weight load of the tubing 24 to the casing 22.
• the induction choke 48 is attached about the tubing string 24 at a second portion 52 downhole above the packer 40.
• a computer system 56 comprising a master modem 58 and a source of time-varying current 60 is electrically connected to the tubing string 24 below the insulating tubing joint 146 by a first source terminal 61.
• the first source terminal 61 is insulated from the hanger 46 where it passes through it.
• a second source terminal 62 is electrically connected to the well casing 22, either directly (as in FIG. 2) or via the hanger 46 (arrangement not shown).
• another induction choke (not shown) can be placed about the tubing 24 above the electrical connection location for the first source terminal 61 to the tubing.
• the time-varying current source 60 provides the current, which carries power and communication signals downhole.
• the time-varying current is preferably alternating current (AC), but it can also be a varying direct current (DC).
• the communication signals can be generated by the master modem 58 and embedded within the current produced by the source 60.
• the communication signal is a spread spectrum signal, but other forms of modulation could be used in alternative.
• the electrically powered device 42 in the packer 40 comprises two device terminals 71, 72, and there can be other device terminals as needed for other embodiments or applications.
• a first device terminal 71 is electrically connected to the tubing 24 on a source-side 81 of the induction choke 48, which in this case is above the induction choke.
• a second device terminal 72 is electrically connected to the tubing 24 on an electrical-return-side 82 of the induction choke 48, which in this case is below the induction choke.
• the slips 28 of the packer 40 provide the electrical connection between the tubing 24 and the well casing 22.
• the electrical connection between the tubing 24 and the well casing 22 can be accomplished in numerous ways, some of which can be seen in the Related Applications, including (but not limited to): another packer (conventional or controllable); conductive fluid in the annulus between the tubing and the well casing; a conductive centralizer; or any combination thereof.
• another packer conventional or controllable
• conductive fluid in the annulus between the tubing and the well casing a conductive centralizer; or any combination thereof.
• a conductive centralizer or any combination thereof.
• FIG. 3 illustrates a simplified electrical schematic of the electrical circuit formed in the well 38 of FIG. 2.
• the insulating tubing joint 146 and the induction choke 48 effectively create an isolated section of the tubing string 24 to contain most of the time- varying current between them. Accordingly, a voltage potential develops between the isolated section of tubing 24 and the well casing 22 when AC flows through the tubing string. Likewise, the voltage potential also forms between tubing 24 on the source-side 81 of the induction choke 48 and the tubing 24 on the electrical-return-side 82 of the induction choke 48 when AC flows through the tubing string.
• the electrically powered device 42 in the packer 40 is electrically connected across the voltage potential between the source-side 81 and the electrical-return-side 82 of the tubing 24.
• the device 42 can be electrically connected across the voltage potential between the tubing 24 and the casing 22, or the voltage potential between the tubing 24 and part of the packer 40 (e.g., slips 28), if that part of the packer is electrically contacting the well casing 22.
• part of the current that travels through the tubing 24 and casing 22 is routed through the device 42 due to the induction choke 48.
• centralizers which are installed on the tubing between isolation device 47 and choke 48 must not provide an electrically conductive path between tubing 24 and casing 22.
• Suitable centralizers may be composed of solid molded or machined plastic, or may be of the bow-spring type provided these are furnished with appropriate insulating elements. Many suitable and alternative design implementations of such centralizers will be clear to those of average skill in the art.
• FIG. 4 shows more details of the packer 40 of FIG. 2, it is seen that the controllable packer 40 is similar to the conventional packer 20 (shown in FIG. 1), but with the addition of an electrically powered device 42 comprising an electrically controllable valve 44 and a communications and control module 84.
• the communications and control module 84 is powered from and communicates with the computer system 56 at the surface 54 via the tubing 24 and/or the casing 22.
• the communications and control module 84 may comprise a modem 86, a power transformer (not shown), a microprocessor (not shown), and/or other various electronic components (not shown) as needed for an embodiment.
• the communications and control module 84 receives electrical signals from the computer system 56 at the surface 54 and decodes commands for controlling the electrically controlled valve 44, which acts as a bypass valve. Using the decoded commands, the communications and control module 84 controls a low current electric motor that actuates the movement of the bypass valve 44. Thus, the valve 44 can be opened, closed, adjusted, altered, or throttled continuously by the computer system 56 from the surface 54 via the tubing 24 and well casing 22.
• the bypass valve 44 of FIG. 4 controls flow through a bypass tube 88, which connects inlet and outlet ports 90, 92 at the bottom and top of the packer 40.
• the ports 90, 92 communicate freely with the annular spaces 94, 96 (between the casing 22 and the tubing 24), above and below the packer 40.
• the bypass control valve 44 therefore controls fluid exchange between these spaces 94, 96, and this exchange may be altered in real time using commands sent from the computer system 56 and received by the controllable packer 40.
• the mechanical arrangement of the packer 40 depicted in FIG. 4 is illustrative, and alternative embodiments having other mechanical features providing the same functional needs of a packer (i.e., fluidly isolating and sealing one casing section from another casing section in a well, and in the case of a controllable packer, regulating and controlling fluid flow between these isolated casing sections) are possible and encompassed within the present invention.
• the inlet and outlet ports 90, 92 may be exchanged to pass fluids from the annular space 94 above the packer 40 to the space 96 below the packer.
• the communications and control module 84 and the bypass control valve 44 may be located in upper portion of the packer 40, above the slips 28.
• the controllable packer 40 may also comprise sensors (not shown) electrically connected to or within the communication and control module 84, to measure pressures or temperatures in the annuli 94, 96 or within the production tubing 24. Hence, the measurements can be transmitted to the computer system 56 at the surface 54 using the communications and control module 84, providing real time data on downhole conditions. Also the setting and unsetting mechanism of the packer slips may be actuated by one or more motors driven and controlled by power and commands received by module 84.
• the electrically powered device 42 of the packer 40 may comprise: a modem 86; a sensor (not shown); a microprocessor (not shown); a packer valve 44; a tracer injection module (not shown); an electrically controllable gas-lift valve (e.g., for controlling the flow of gas from the annulus to inside the tubing) (not shown); a tubing valve (e.g., for varying the flow of a tubing section, such as an application having multiple branches or laterals) (not shown); a communications and control module 84; a logic circuit (not shown); a relay modem (not shown); other electronic components as needed (not shown); or any combination thereof.
• a modem 86 e.g., a sensor (not shown); a microprocessor (not shown); a packer valve 44; a tracer injection module (not shown); an electrically controllable gas-lift valve (e.g., for controlling the flow of gas from the annulus to inside the tubing) (not shown); a
• controllable packers and/or multiple induction chokes there may be multiple controllable packers and/or multiple induction chokes.
• Such electrical insulation of a packer may be achieved in various ways apparent to one of ordinary skill in the art, including (but not limited to): an insulating sleeve about the tubing at the packer location; a rubber or urethane portion at the radial extent of the packer slips; an insulating coating on the tubing at the packer location; forming the slips from non-electrically-conductive materials; other known insulating means; or any combination thereof.
• the present invention also can be applied to other types of wells (other than petroleum wells), such as a water well.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Mining & Mineral Resources (AREA)
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• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
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• Geochemistry & Mineralogy (AREA)
• Geophysics (AREA)
• Electromagnetism (AREA)
• Earth Drilling (AREA)
• Pipeline Systems (AREA)
• Electrically Driven Valve-Operating Means (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Gasket Seals (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• General Details Of Gearings (AREA)
• Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)

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Citations (11)

• 2001
  • 2001-03-02 RU RU2002126210/03A patent/RU2262597C2/ru active
  • 2001-03-02 CA CA002401730A patent/CA2401730C/en not_active Expired - Fee Related
  • 2001-03-02 OA OA1200200278A patent/OA12321A/en unknown
  • 2001-03-02 WO PCT/US2001/006984 patent/WO2001065067A1/en active IP Right Grant
  • 2001-03-02 BR BR0108887-4A patent/BR0108887A/pt active Search and Examination
  • 2001-03-02 EP EP01918345A patent/EP1259709B1/en not_active Expired - Lifetime
  • 2001-03-02 AU AU4543301A patent/AU4543301A/xx active Pending
  • 2001-03-02 MX MXPA02008582A patent/MXPA02008582A/es active IP Right Grant
  • 2001-03-02 DE DE60125020T patent/DE60125020T2/de not_active Expired - Fee Related
  • 2001-03-02 AU AU2001245433A patent/AU2001245433B2/en not_active Ceased
• 2002
  • 2002-08-30 NO NO20024145A patent/NO324145B1/no not_active IP Right Cessation

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