GB2309471A

GB2309471A - Downhole production well instrumentation

Info

Publication number: GB2309471A
Application number: GB9701612A
Authority: GB
Inventors: Paulo Tubel
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1996-01-25
Filing date: 1997-01-27
Publication date: 1997-07-30
Also published as: GB9701612D0; NO970321D0; CA2195896A1; NO970321L; AU1234597A

Abstract

A downhole production instrumentation comprising a modular tool 16 used in the acquisition and control of information, and actuation of electromechanical devices in a production well. The tool 16 is suitable for both permanent and retrievable applications for measurement of production fluid and geological formation parameters. Multi well/multi-zone monitoring and control can also be provided with the instrumentation of the present invention. A data acquisition surface unit located at the surface provides production well monitoring and control. The tool 16 comprises a plurality of interchangeable instrumentation modules 20a-h and a control module 22. Interface between the downhole control module and the data acquisition surface unit 18 is provided over a single conductor cable 32, which supports both communication and power over a single conductor. This cable may be connected to a plurality of tools in a corresponding plurality of zones by a parallel connection to the single conductor. Each tool 16 has a unique address for communication with the data acquisition surface unit . Each instrumentation module 20a-h interfaces over a tool bus with the control module 22. A standard interface and connection between modules allows the tool 16 to be configured (or reconfigured) using a control module any one or a number of interchangeable instrumentation modules. The downhole modules include instrumentation (sensors), such as, pressure, temperature and flow gauges, gamma ray and pulse neutron detectors, or any other suitable devices for measuring production fluid, geological parameters and the like.

Description

DOWNHOLE PRODUCTION WEILL INSTRUM=TION Background of the Invention: This invention relates generally to downhole production well instrumentation. More particularly, this invention relates to downhole production well instrumentation comprising a plurality of interchangeable modules.

The control of oil and gas production wells constitutes an on-going concern of the petroleum industry due, in part, to the enormous monetary expense involved as well as the risks associated with environmental and safety issues. Production well control has become particularly important and more complex in view of the industry wide recognition that wells having multiple branches (i.e., multilateral wells) will be increasingly important and commonplace. Such multilateral wells include discrete production zones which produce fluid in either common or discrete production tubing. In either case, there is a need for controlling zone production, isolating specific zones and otherwise monitoring each zone in a particular well.

Before describing the current state-of the-art relative to such production well control systems and methods, a brief description will be made of the production systems, per se.

One type of production system utilizes electrical submersible pumps (ESP) for pumping fluids from downhole. In addition, there are two other general types of productions systems for oil and gas wells, namely plunger lift and gas lift. Plunger lift production systems include the use of a small cylindrical plunger which travels through tubing extending from a location adjacent the producing formation down in the borehole to surface equipment located at the open end of the borehole. In general, fluids which collect in the borehole and inhibit the flow of fluids out of the formation and into the wellbore, are collected in the tubing. Periodically, the end of the tubing is opened at the surface and the accumulated reservoir pressure is sufficient to force the plunger up the tubing.The plunger carries with it to the surface a load of accumulated fluids which are ejected out the top of the well thereby allowing gas to flow more freely from the formation into the wellbore and be delivered to a distribution system at the surface. After the flow of gas has again become restricted due to the further accumulation of fluids downhole, a valve in the tubing at the surface of the well is closed so that the plunger then falls back down the tubing and is ready to lift another load of fluids to the surface upon the reopening of the valve.

A gas lift production system includes a valve system for controlling the injection of pressurized gas from a source external to the well, such as another gas well or a compressor, into the borehole. The increased pressure from the injected gas forces accumulated formation fluids up a central tubing extending along the borehole to remove the fluids and restore the free flow of gas and/or oil from the formation into the well. In wells where liquid fall back is a problem during gas lift, plunger lift may be combined with gas lift to improve efficiency.

In both plunger lift and gas lift production systems, there is a requirement for the periodic operation of a motor valve at the surface of the wellhead to control either the flow of fluids from the well or the flow of injection gas into the well to assist in the production of gas and liquids from the well. These motor valves are conventionally controlled by timing mechanisms and are programmed in accordance with principles of reservoir engineering which determine the length of time that a well should be either "shut in" and restricted from the flowing of gas or liquids to the surface and the time the well should be "opened" to freely produce. Generally, the criteria used for operation of the motor valve is strictly one of the elapse of a preselected time period.In most cases, measured well parameters, such as pressure, temperature, etc. are used only to override the timing cycle in special conditions.

It will be appreciated that relatively simple, timed intermittent operation of motor valves and the like is often not adequate to control either outflow from the well or gas injection to the well so as to optimize well production. As a consequence, sophisticated computerized controllers have been positioned at the surface of production wells for control of downhole devices such as the motor valves.

In addition, such computerized controllers have been used to control other downhole devices such as hydro-mechanical safety valves. These typically microprocessor based controllers are also used for zone control within a well and, for example, can be used to actuate sliding sleeves or packers by the transmission of a surface command to downhole microprocessor controllers and/or electromechanical control devices.

Typically, production permanent gauges are placed in a wellbore to monitor parameters related to the production of hydrocarbons during the life of the welL These gauges are connected electrically to the surface via a cable normally mounted to the outside of the production tubing. Power and communications are accomplished over the cable.

Generally, one wire is used for each gauge placed downhole. The surface system used to gather and process the data requires an individual data acquisition system for each gauge placed downhole. This large number of data acquisition systems increases the complexity and cost of the system, as well as decreases the reliability of the surface hardware. The use of multiple downhole wires increase the cost of deploying a system, and limits the number of gauges that can be placed in the well.

Electrically submersible pumps use pressure and temperature readings received at the surface from downhole sensors to change the speed of the pump in the borehole. As an alternative to downhole sensors, wire line production logging tools are also used to provide downhole data on pressure, temperature, flow, gamma ray and pulse neutron using a wire line surface unit. This data is then used for control of the production well.

There are numerous prior art patents related to the control of oil and gas production wells. In general, these prior patents relate to (1) surface control systems using a surface microprocessor and (2) downhole control systems which are initiated by surface control signals.

The surface control system patents generally disclose computerized systems for monitoring and controlling a gas/oil production well whereby the control electronics is located at the surface and communicates with sensors and electromechanical devices near the surface. An example of a system of this type is described in U.S. Patent 4,633,954 C954) to Dixon et aL The system described in the '954 patent includes a fully programmable microprocessor controller which monitors downhole parameters such as pressure and flow and controls the operation of gas injection to the well, outflow of fluids from the well or shutting in of the well to maximize output of the welL Another example of a control system of this type is described in U.S. Patent 5,132,904 C904) to Lamp.The '904 patent discloses a system similar to the '954 patent and in addition also describes a feature wherein the controller includes serial and parallel communication ports through which all communications to and from the controller pass. Hand held devices or portable computers capable of serial communication may access the controller. A telephone modem or telemetry link to a central host computer may also be used to permit several controllers to be accessed remotely.

U.S. Patent 4,757,314 ('314) to Aubin et al describes an apparatus for controlling and monitoring a well head submerged in water. This system includes a plurality of sensors, a plurality of electromechanical valves and an electronic control system which communicates with the sensors and valves. The electronic control system is positioned in a water tight enclosure and the water tight enclosure is submerged underwater. The electronics located in the submerged enclosure control and operate the electromechanical valves based on input from the sensors. In particular, the electronics in the enclosure uses the decision making abilities of the microprocessor to monitor the cable integrity from the surface to the well head to automatically open or close the valves should a break in the line occur.

The downhole control system patents generally disclose downhole microprocessor controllers, electromechanical control devices and sensors. Examples include U.S. Patent No. 4,718,011 (011) to Patterson; U.S. Patent No. 5,273,113 ( 113) to Schultz; and U.S.

Patent No. 3,959,767 (z767) to Smither et aL The '113 patent describes a system for remotely controlling a downhole tool in a welL A plurality of substantially identical command signals are transmitted into the well.

Each of the command signals is received at the downhole tool by a controller having information stored therein identifying an operative command signal signature associated with that tooL The '011 patent describes a downhole microprocessor controller disposed in a well logging sonde which receives and stores one or more preselected tables or series of logging tool commands down loaded from a surface computer through a logging cable telemetry link.

All such commands in a given table are called up by the controller from memory in response to a corresponding sequence command from the surface computer corresponding with the desired table.

The '767 patent describes an apparatus for communicating, in digital form, information from a plurality of analog sources located in a borehole to a location on the surface. A multiplexer is provided with a plurality of inputs for connecting the analog signal output of the data sources to an analog to digital converter in response to a sequence control circuit. The digital data signals and their addresses are applied to modulate or vary the power factor of power on a power cable mounted in the borehole. Receiver means is provided at the surface location for recovering the digital data and address signals for use on the surface.

While it is well recognized that petroleum production wells will have increased production efficiencies and lower operating costs if surface computer based controllers and downhole microprocessor controller (actuated by external or surface signals) of the type discussed hereinabove are used, the presently implemented control systems nevertheless suffer from drawbacks and disadvantages.

In multilateral wells where multiple zones are controlled by a single surface control system, an inherent risk is that if the surface control system fails or otherwise shuts down, then all of the downhole tools and other production equipment in each separate zone will similarly shut down leading to a large loss in production and, of course, a loss in revenue.

Still another significant drawback of present production well control systems involves the extremely high cost associated with implementing changes in well control and related work over operations. Presently, if a problem is detected at the well, the customer is required to send a rig to the well site at an extremely high cost (e.g., 5 million dollars for 30 days of offshore work). The well must then be shut in during the work over causing a large loss in revenues (e.g., 1.5 million dollars for a 30 day period). Associated with these high costs are the relatively high risks of adverse environmental impact due to spills and other accidents as well as potential liability of personnel at the rig site. Of course, these risks can lead to even further costs.Because of the high costs and risks involved, in general, a customer may delay important and necessary work over of a single well until other wells in that area encounter problems. This delay may cause the production of the well to decrease or be shut in until the rig is brought in.

Still other problems associated with present production well control systems involve the need for wireline formation evaluation to sense changes in the formation and fluid composition. Unfortunately, such wireline formation evaluation is extremely expensive and time consuming. In addition, it requires shut-in of the well and does not provide "real time" information. The need for real time information regarding the formation and fluid is especially acute in evaluating undesirable water flow into the production fluids.

Summarv of the Invention: The above-discussed and other problems and deficiencies of the prior art are overcome or alleviated by the downhole production well instrumentation of the present invention. In accordance with the present invention, the downhole production instrumentation comprises a modular tool used in the acquisition and control of information, and actuation of electromechanical devices in a production well. The tool is suitable for both permanent and retrievable applications for measurement of production fluid and geological formation parameters. Multi well/multizone monitoring and control can also be provided with the instrumentation of the present invention. A data acquisition surface unit located at the surface provides production well monitoring and controL The tool comprises a plurality of interchangeable instrumentation modules and a control module.Interface between the downhole control module and the data acquisition surface unit is provided over a single conductor cable, which supports both communication and power over a single conductor as is well known in the art. This cable may be connected to a plurality of tools in a corresponding plurality of zones by a parallel connection to the single conductor. Each tool will preferably have a unique address for communication with the data acquisition surface unit.

Each instrumentation module interfaces over a tool bus with the control module. It is an important feature of the present invention that a standard interface and connection be developed, whereby a tool may be configured (or reconfigured) using a control module any one or a number of interchangeable instrumentation modules. The downhole modules include instrumentation (sensors), such as, pressure, temperature and flow gauges, gamma ray and pulse neutron detectors, or any other suitable devices for measuring production fluid, geological parameters and the like. The modular approach of the present invention allows a plurality of devices to be combined at any location in a tool prior to being placed in the production borehole.

The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.

Brief Descrintion of the Drawing: Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: FIGURE 1 is a diagrammatic elevation view of a production wellhole employing a modular tool in accordance with the present invention; FIGURE 2 is a diagrammatic elevation view of a multizone production wellhole employing a plurality of modular tools in accordance with the present invention; FIGURE 3 is a block diagram of the modular tool of FIGURE 1; FIGURE 4 is a schematic block diagram of the tool and tool bus in accordance with the present invention; FIGURE 5 is a schematic block diagram the control module in the tool of FIGURE 1; and FIGURE 6 is a schematic block diagram of the intelligent portion found in each of the interchangeable instrumentation modules of the tool of FIGURE 1.

DescriDtion of the Preferred Embodiment: Referring to FIGURES 1 and 3, a production well (lie., completed well) 10 enclosed by a casing 12 with a rig 14 at the surface is generally shown, such being well known in the art. A downhole instrumentation tool in accordance with the present invention is generally shown at 16. Tool 16 is used in the acquisition and control of information, and actuation of electromechanical devices in a production welL It is within the scope of the present invention that tool 16 is suitable for both permanent (ie., the tool remains downhole throughout production operations) and retrievable applications for measurement of production fluid and geological formation parameters. Multi welllmultizone monitoring and control (FIGURE 2) can also be provided with the instrumentation of the present invention.

A data acquisition surface unit 18 located at the surface (or platform) provides production well monitoring and control, such being fully described in U.S. Patent Application No.

08/385,992 entitled DOWNHOLE PRODUCTION WELL CONTROL SYSTEM AND METHOD, filed February 9, 1995, by Paulo Tubel et al, which is expressly incorporated herein by reference in its entirety.

Instrumentation tool 16 comprises a plurality of interchangeable modules 20a-h and a control module 22. Interface between the downhole control module 22 and data acquisition surface unit 18 is provided over a single conductor cable 32. Cable 32 supports both communication and power over a single conductor as is well known in the art.

Further, with reference being made to FIGURE 2, cable 32 is connected to a plurality of tools in a corresponding plurality of zones by a parallel connection to the single conductor.

Each tool will preferably have a unique address for communication with data acquisition surface unit 18.

Referring also to FIGURE 4, each module 20a-h interfaces over a tool bus 24 (ie., a multi-conductor cable) with control module 22. Each module 20a-h and 22 is preferably connected in parallel to bus 24, although a daisy chain serial connection could be employed.

Modules 20a-h and 22 are attached to bus 24 by predefined connector pins at the top and/or bottom of each of the modules. It is an important feature of the present invention that a standard interface and connection be developed, whereby a tool may be configured (or reconfigured) using a control module any one or a number of interchangeable instrumentation modules.

The tool bus 24 comprises: a digital data transfer bus (having one or more signal lines) 36; a low power voltage line 38; a high power voltage line 40; and a ground (or return) line 42. Digital data transfer bus 36 has one or more signal lines (a differential signal) utilizing a standard transmission method for all downhole modules, e.g., RS-232, RS-485, or Mil Spec 1553. More importantly, a standard communication system is used which will allow compatibility/interchangability of the downhole modules. The transfer of data from a module 20a-h to the control module 22 can be initiated by the control module requesting data or can be programmed into module 20a-h to transmit data at specific time intervals.

Control module 22 determines bus status, i.e., if the bus is being used, and will take over the bus if it determines that the data transfer lines are not being used.

Referring to FIGURE 5, control module 22 comprises a control circuit 44. A low voltage power circuit 46 is provided for delivering low voltage power over the tool bus (2ine 38 and return line 42) to modules 20a-h. A high voltage power circuit 48 is provided for delivering high voltage power over the tool bus Oine 40 and return line 42) to modules 20a-h for operation of high power devices. High voltage power circuit 48 is controlled by control circuit 44, whereby control circuit 44 will enable the high voltage power in response to a command sent to a particular module 20a-h to start the operation of the high power device located in the particular module.The high voltage power is required for operation of certain downhole high power electromechanical devices, e.g., explosives, or any high voltage/high current system. The use of separate high and low voltage power lines helps to prevent corruption of the low voltage power line, as electrical noise typically created by the operation an electromechanical device such as a motor will primarily only be present on the high voltage power line.

Control module 22 further includes a data transfer circuit 50 for transmitting to and receiving data from the downhole modules. Data transfer circuit 50 communicates over the digital interface bus line 36 and is controlled by control circuit 44. A communication circuit 52 is provided for telemetry of data between the surface and downhole and vice versa. A surface/downhole interface circuit 54 is provided to regulate the power interfaces. Control circuit 44 also decodes and formats the data to interface with the data acquisition surface unit for processing the data. The data acquisition surface unit may include a printer/plotter for generating a paper record of events occurring in the well, e.g., production/formation evaluation logs.

Telemetry for exchanging information is preferably digital In accordance with which, a unique address is transmitted from the data acquisition surface unit to the downhole tool (or tools, FIGURE 2), followed by data or a command transmission. The downhole modules via the control module receive the information and determine if the address it was programmed with matches the address sent from the surface (ie., all modules in that tool receive the same transmitted information on the bus). Only the tool that has the proper address will respond to the command from the surface. Thereafter the corresponding downhole module in the selected tool will activate as instructed, e.g., close a valve, or will transmit collected data, in accordance with the commands The data acquisition surface unit will continuously pole the downhole tool (or tools) for information and status.

Referring to FIGURE 6, each module 20a-h includes a micro controller 56, non volatile memory 58, a communications bus interface circuit 60, an analog to digital converter 62, an analog sensor conditioner circuit 64 and a power conditioner circuit 66.

Micro controller 56 preferably includes, in the same silicon wafer, the central processing unit, non volatile memory, random access memory, and a real time clock. Internal timers perform the data processing, provide the timing for the data acquisition, and pack the data for transfer to control module 22. Micro controller 56 could be replaced with a microprocessor. Micro controller 56 also decodes commands received from control module 22. Non volatile memory 58 contains codes used by micro controller 58 to perform preprogrammed functions. Bus interface circuit 60 converts the voltages from the communications bus to the digital levels compatible to micro controller 58. Bus interface circuit 60 also interfaces with bus 24. Analog to digital converter 62 digitizes the data from the sensors, e.g., pressure sensor, temperature sensor, flow sensor, ect.Analog sensor conditioner circuit 64 provides the signal to drive the sensor, and process the raw data for compatibility with analog to digital converter 62. Power conditioner circuit 66 conditions the power from control module 22 to generate the voltages required to operate the sensors and electronics within the module.

By way of example, the tool comprises control module 22, pressure module 20a, temperature module 20b, fluid flow module 20c, water cut sensor module 20d, scaling removal module 20e, resistivity module 20f, acoustic module 20g and electromechanical module (ie., a fluid flow control sub) 20h.

Control module 22 provides the following functions: (1) communications between the surface and downhole; (2) control of downhole modules; (3) data transfer among modules; (4) power conversion to provide the required voltage and current to the modules; and (5) data packaging for transfer to the surface.

Control module 22 generates the functions required to provide power and communications to the modules that comprise the downhole tool 16. Pressure module 20a comprises a pressure sensor for sensing the annulus or tubing pressure that is used to the determine the optimum fluid production from a particular geological zone to the wellbore. Temperature module 20b comprises a temperature sensor wherein the sensed temperature is used to correct the pressure movements and to determine if an electrical submersible pump (ESP) is malfunctioning. Fluid flow module 20c comprises a fluid flow sensor with the flow measurement indicating of the amount of fluid that is flowing through a particular zone in the well. Water cut sensor module 20d comprises a water cut sensor to determine the amount of water, oil, gas and solids that are flowing by the sensor.It is well known in the art that so-called 'scaling' is a major problem in a producing well. More specifically, the accumulation of such things as paraffin can reduce the flow area in the tubing reducing the amount of hydrocarbons that can be recovered from the well. Scaling removal module 20e is provided to remove these accumulations in the production tubing. Electromechanical sub 20h is used to actuate a device such as a sliding sleeve, for flow control from a zone in the well, and a packer used for the isolation of different zones in the borehole. The resistivity and acoustic modules 20f, 20g monitor the water movement in the producing formations.

The downhole modules may comprises instrumentation (sensors), such as, pressure, temperature and flow gauges, gamma ray and pulse neutron detectors, or any other suitable devices for measuring production fluid, geological parameters and the like. The modular approach of the present invention allows a plurality of devices to be combined at any location in a tool 16 prior to being placed in the production borehole 10. A module can also be configured to communicate with sensors that are installed permanently downhole, e.g. a formation evaluation sensor. Moreover, these sensors can, in real time, sense and evaluate formation parameters including important information regarding water migrating from different zones.Significantly, this information can be obtained prior to the water actually entering the producing tubing and therefore corrective action (e.g., closing of a valve or sliding sleeve) or formation treatment can be taken prior to water being produced. This real time acquisition of formation data in the production well constitutes an important advance over current wireline techniques in that the present invention is far less costly and can anticipate and react to potential problems before they occur. In addition, the formation evaluation sensors themselves can be placed much closer to the actual formation (ie., adjacent the casing or downhole completion tool) then wireline devices which are restricted to the interior of the production tubing.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.

Claims

CLAIM 1. A downhole tool comprising:

a control module having an uphole interface assembly for communication and power and having a downhole interface assembly for communication and power; a plurality of interchangeable instrumentation modules each having a module interface assembly; and a bus interconnecting each of said module interface assemblies of said instrumentation modules with said downhole interface assembly of said control module.

CLAIM 2. The tool of claim 1 wherein said bus includes: a digital transfer bus; a high voltage power line; and a low voltage power line.

CLAIM 3. The tool of claim 1 wherein said bus comprises a single conductor for both (1) data or command and (2) power.

CLAIM 4. The tool of claim 1 wherein: said up hole interface assembly comprises, (1) a surface/downhole interface circuit for separating (1) data or command and (2) power signals, and (2) a communications circuit communicating with said surface/downhole interface circuit for transmitting said data or command signals to and receiving said data or command signals from uphole; said downhole interface assembly comprises, (1) a data transfer circuit for transmitting module data to and receiving module data or commands from said instrumentation module, (2) a high voltage power circuit power receptive to said power signals from said surface/downhole interface circuit for providing high voltage power, and (3) a low voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing low voltage power; and said control module further comprises, a control circuit for controlling said uphole and downhole interface assemblies.

CLAIM 5. The tool of claim 1 wherein each of said instrumentation modules includes: a sensor.

ClAIM 6. The tool of claim 1 wherein each of said instrumentation modules includes: a sensor; an analog to digital converter for converting said analog output signals to digital sensor output signals; a memory for storing program signals; a controller responsive to said program signals and command signals from said control module to perform functions, said controller for processing said digital sensor output signals; and said module interface assembly comprises, a power interface circuit for conditioning power from said control module to said sensor, and a communication bus interface circuit for providing an interface between said bus and said controller CLAIM 7. The tool of claim 6 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.

CLAIM 8. The tool of claim 5 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.

CLAIM 9. The tool of claim 5 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.

CLAIM 10. An instrument module comprising: a sensor; an analog to digital converter for converting analog output signals of said sensor to digital sensor output signals; a memory for storing program signals; a controller responsive to said program signals and command signals to perform functions, said controller for processing said digital sensor output signals; and an interface including, a power interface circuit for conditioning power to said sensor, and a communication interface circuit for providing data communication with said controller.

CLAIM 11. The instrument module of claim 10 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.

CLAIM 12. The instrument module of claim 10 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.

CLAIM 13. The tool of claim 10 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.

CLAIM 14. A downhole tool comprising: a control module having an uphole interface assembly for communication and power and having a downhole interface assembly for communication and power; and an instrumentation module having a module interface assembly connected to said downhole interface assembly of said control module.

CLAIM 15. The tool of claim 14 further comprising: a bus interconnecting said module interface assembly of said instrumentation module and said downhole interface assembly of said control module.

CLAIM 16. The tool of claim 14 wherein said bus includes: a digital transfer bus; a high voltage power line; and a low voltage power line.

CLAIM 17. The tool of claim 14 wherein said bus comprises a single conductor for both (1) data or command and (2) power.

CLAIM 18. The tool of claim 14 wherein: said uphole interface assembly comprises, (1) a surface/downhole interface circuit for separating (1) data or command and (2) power signals, and (2) a communications circuit communicating with said surface/downhole interface circuit for transmitting said data or command signals to and receiving said data or command signals from uphole; said downhole interface assembly comprises, (1) a data transfer circuit for transmitting module data or commands to and receiving module data or commands from said instrumentation module, (2) a high voltage power circuit power receptive to said power signals from said surface/downhole interface circuit for providing high voltage power, and (3) a low voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing low voltage power; and said control module further comprises, a control circuit for controlling said uphole and downhole interface assemblies.

CLAIM 19. The tool of claim 14 wherein said instrumentation module includes: a sensor.

CLAIM 20. The tool of claim 15 wherein said instrumentation module further includes: a sensor; an analog to digital converter for converting analog sensor output signals to digital sensor output signals; a memory for storing program signals; a controller responsive said program signals and command signals from said control module to perform functions. said controller for processing said digital sensor output signals; and said module interface assembly comprises, a power interface circuit for conditioning power from said control module to said sensor, and a communication bus interface circuit for providing an interface between said bus and said controller.

CLAIM 21. The tool of claim 20 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.

CLAIM 22. The tool of claim 19 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.

CLAIM 23. The tool of claim 19 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.

CLAIM 24. The tool of claim 1 wherein said bus comprises multiple conductors such that variable combinations of such multiple conductors can be used for(l) data or command and (2) power.

CLAIM 25. The tool of claim 14 wherein said bus comprises multiple conductors such that variable combinations of such multiple conductors can be used for(l) data or command and (2) power.

CLAIM 26. A downhole tool substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows CLAIM 1. A permanent downhole tool for use in a production well comprising: a control module having an uphole interface assembly for communication and power and having a downhole interface assembly for communication and power; a plurality of instrumentation modules associated with said control module, each of said instrumentation modules having a module interface assembly; each of said instrumentation modules being interchangeable with other instrumentation modules prior to permanent installation downhole in the production well; a bus interconnecting each of said module interface assemblies of said instrumentation modules with said downhole interface assembly of said control module; and wherein said control module and instrumentation modules are permanently installed downhole in the production well.
CLAIM 2. A tool of claim l wherein said bus includes: a digital transfer bus; a high voltage power line: and a low voltage power line.
CLAIM 3. The tool of claim 1 wherein said bus comprises a single conductor for both (1) data or command and (2) power.
CLAIM 4. The tool of claim 1 wherein: said uphole interface assembly comprises.

(1) a surface/downhole interface circuit for separating (1) data or command and (2) power signals, and (2) a communications circuit communicating with said surface/downhole interface circuit for transmitting said data or command signals to and receiving said data or command signals from uphole; said downhole interface assembly comprises, (1) a data transfer circuit for transmitting module data to and receiving module data or commands from said instrumentation module, (2) a high voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing high voltage power, and (3) a low voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing low voltage power; and said control module further comprises, a control circuit for controlling said uphole and downhole interface assemblies.
CLAIM 5. The tool of claim 1 wherein each of said instrumentation modules includes: a sensor.
CLAIM 6. The tool of claim 1 wherein each of said instrumentation modules includes: a sensor; an analog to digital converter for converting said analog output signals to digital sensor output signals; a memory for storing program signals; a controller responsive to said program signals and command signals from said control module to perform functions, said controller for processing said digital sensor output signals; and said module interface assembly comprises, a power interface circuit for conditioning power from said control module to said sensor, and a communication bus interface circuit for providing an interface between said bus and said controller.
CLAIM 7. The tool of claim 6 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.
CLAIM 8. The tool of claim 5 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.
CLAIM 9. The tool of claim 5 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.
CLAIM 10. An instrument module comprising: a sensor; an analog to digital converter for converting analog output signals of said sensor to digital sensor output signals; a memory for storing program signals; a controller responsive to said program signals and command signals to perform functions, said controller for processing said digital sensor output signals; and an interface including, a power interface circuit for conditioning power to said sensor, and a communication interface circuit for providing data communication with said controller.
CLAIM 11. The instrument module of claim 10 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.
CLAIM 12. The instrument module of claim 10 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.
CLAIM 13. The tool of claim 10 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.
CLAIM 14. A permanent downhole tool for use in a production well comprising: a control module having an uphole interface assembly for communication and power anc having a downhole interface assembly for communication and power; an instrumentation module having a module interface assembly connected to said downhole interface assembly of said control module; and wherein said control module and instrumentation module are permanently installed downhole in the production well.
CLAIM 15. The tool of claim 14 further comprising: a bus interconnecting said module interface assembly of said instrumentation module and said downhole interface assembly of said control module.
CLAIM 16. The tool of claim 15 wherein said bus includes: a digital transfer bus; a high voltage power line; and a low voltage power line.
CLAIM 17. The tool of claim 15 wherein said bus comprises a single conductor for both (1) data or command and (2) power.
CLAIM 18. The tool of claim 14 wherein: said uphole interface assembly comprises, (1) a surface/downhole interface circuit for separating (1) data or command and (2) power signals, and (2) a communications circuit communicating with said surface/downhole interface circuit for transmitting said data or command signals to and receiving said data or command signals from uphole; ; said downhole interface assembly comprises, (1) a data transfer circuit for transmitting module data or commands to and receiving module data or commands from said instrumentation module, (2) a high voltage power circuit receptive to said power signals from said surfaceldownhole interface circuit for providing high voltage power, and (3) a low-voltage power circuit receptive to said power signals from said surfaceldownhole interface circuit for providing low voltage power; and said control module further comprises, a control circuit for controlling said uphole and downhole interface assemblies.
CLAIM 19. The tool of claim 14 wherein said instrumentation module includes: a sensor.
CLAIM 20. The tool of claim 15 wherein said instrumentation module further includes: a sensor; an analog to digital converter for converting analog sensor output signals to digital sensor output signals; a memory for storing program signals; a controller responsive said program signals and command signals from said control module to perform functions, said controller for processing said digital sensor output signals; and said module interface assembly comprises, a power interface circuit for conditioning power from said control module to said sensor, and a communication bus interface circuit for providing an interface between said bus and said controller.
CLAIM 21. The tool of claim 20 further comprising: an analog sensor conditioner circuit for conditioning said analog output signals.
CLAIM 22. The tool of claim 19 wherein said sensor comprises a pressure sensor, a temperature sensor, a fluid flow sensor, a water cut sensor, a scaling removal device, a resistivity sensor, an acoustic device or an electromechanical device.
CLAIM 23. The tool of claim 19 wherein said sensor comprises a sensor for communicating with devices installed permanently downhole.
CLAIM 24. A downhole tool comprising: a control module having an uphole interface assembly for communication and power and having a downhole interface assembly for communication and power; a plurality of interchangeable instrumentation modules each having a module interface assembly; and a bus interconnecting each of said module interface assemblies of said instrumentation modules with said downhole interface assembly of said control module, said bus including a digital transfer bus, a high voltage power line, and a low voltage power line.
CLAIM 25. The tool of claim 24 wherein said bus comprises a single conductor for both (1) data or command and (2) power.
CLAIM 26. The tool of claim 24 wherein: said uphole interface assembly comprises: (1) a surfaceldonhole interface circuit for separating (1) data or command and (2) power signals; and (2) a communications circuit communicating with said surface/downhole interface circuit for transmitting said data or command signals to and receiving said data or command signals fro uphole; said downhole interface assembly comprises; (1) a data transfer circuit for transmitting module data to and receiving module data or commands from said instrumentation module; (2) a high voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing high voltage power; and (3) a low voltage power circuit receptive to said power signals from said surface/downhole interface circuit for providing low voltage power; and said control module further comprises; a control circuit for controlling said uphole and downhole interface assemblies.
CLAIM 27. The tool of claim 24 wherein said bus comprises multiple conductors such that variable combinations of such multiple conductors can be used for (1) data or command and (2) power.
CLAIM 28. The tool of claim 1 wherein said bus comprises multiple conductors such that variable combinations of such multiple conductors can be used for (1) data or command and (2) power.
CLAIM 29. The tool of claim 14 wherein said bus comprises multiple conductors such that variable combinations of such multiple conductors can be used for (1) data or command and (2) power.
CLAIM 30. A downhole tool substantially as hereinbefore described with reference to the accompanying drawings.