BOTTOM HOLE PRESSURE AND TEMPERATURE INDICATOR

• US 3,732,728 A
• Filed: 01/04/1971
• Issued: 05/15/1973
• Est. Priority Date: 01/04/1971
• Status: Expired due to Term

• Current Assignee: John R. Fitzpatrick
• Original Assignee: John R. Fitzpatrick
• Inventors: Fitzpatrick, John R.
• Primary Examiner(s): Myracle, Jerry W.
• Application Number:
  US05/103,721
• Time in Patent Office: 862 Days
• Field of Search: 73/151,154,152 340/18NC 181/.5BE
• US Class Current: 340/854.4
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure
• CPC Class Codes: E21B 47/13 by electromagnetic energy, e.g. radio frequency
• CPC Class Codes: E21B 47/16 through the drill string or casing , e.g. by torsional acoustic waves

Abstract

A bottom hole indicator for determining the pressure and temperature at the bottom of a well bore, and which is particularly designed and constructed for substantially permanent bottom hole installation of the pressure and temperature sensing instrumentation utilizing existing oil well tubing as an information conductor, and the portability of the well head information collection and recording equipment for permitting frequent and economical measurements of reservoir pressure and temperature at the bottom of the well bore.

Claims

1. In combination with an oil well bore having well tubing extending therein, a bottom hole indicator for measuring the fluid reservoir pressure at the bottom of said oil well bore, comprising self-contained bottom instrumentation means substantially permanently installed in the well bore in the proximity of the bottom of the well tubing, said bottom hole instrumentation means comprising pressure sensing means, acoustical transmitting means operably connected to the pressure sensing means for producing and transmitting acoustical pulse data to the surface of the well, the said acoustical pulse data having a frequency directly proportional to the fluid reservoir pressure, data receiving means and processing means disposed at the surface of the well for receiving the pressure data from the bottom hole instrumentation means and for proceSsing said data, and means operably connected to the processing means for recording and displaying said data, said transmitting means transmitting said data from the bottom hole instrumentation means to the data receiving means and processing means along the well tubing with said tubing acting as a conductor.

2. A bottom hole indicator for measuring the fluid reservoir pressure at the bottom of an oil well bore as set forth in claim 1 wherein the bottom hole instrumentation means comprises an elongated cylindrical housing open at each end, one end of said housing being threadedly secured to the bottom end of the well tubing in open communication with the fluid reservoir in said tubing, a cover plate removably secured to the opposite end of said housing, sealing means interposed between the housing and cover plate, said housing being compartmentized into an upper pressure compartment and a lower sensing and transmitting compartment, said compartments being separated by a partition plate rigidly secured to the inner walls of the cylindrical housing, the upper pressure compartment comprising cylindrical piston means slidably disposed therein, the upper surface of the piston being in contact with the fluid reservoir in the well tubing and an incompressible system fluid whose viscosity is substantially not affected by temperature change disposed between the piston and the partition plate whereby the system fluid pressure is the same as the reservoir pressure, a needle valve means centrally disposed within said partition plate for providing communication between the upper and lower compartments, said valve means comprising a centrally disposed vertical bore in the partition plate, the top of the bore being countersunk to provide a valve seat, a valve gate member comprising a cylindrical operator shaft of cross-sectional diameter substantially smaller than that of the vertical bore extending through said bore, and a gate member having a lower surface configuration complementary to the valve seat rigidly secured to the upper end of the operator shaft;

the lower sensing and transmitting compartment comprising an inner housing rigidly secured to the lower surface of the partition plate to define a subcompartment, said inner housing having a fluid exhaust port in the lower portion thereof, said subcompartment being in communication with the upper pressure compartment through the needle valve means, an off-center-axis rotatable operator cam disposed within the subcompartment spaced below the needle valve bore, the lower end of the needle valve operator shaft being journalled through the vertical bore and engagable with the operator cam surface, a fluid tight clock drive means disposed within the subcompartment and comprising internal power supply and output drive shaft, the output drive shaft being operably connected with the operator cam for rotating said cam in alternately opening and closing the needle valve thereby permitting system fluid to flow from the upper pressure compartment into the subcompartment at a rate which is a function of the system fluid pressure, a meter type hydraulic motor secured to the subcompartment housing and having a rotatable output meter shaft, said motor including housing having an inlet port in communication with the subcompartment fluid exhaust port for receiving system fluid therethrough and an outlet port in communication with the lower compartment, said meter shaft extending into the lower compartment and having a rotational rate proportional to the flow rate of system fluid from the upper compartment through the needle valve and into the subcompartment, a striker cam rotatably disposed within the lower compartment and operably connected with the meter shaft for rotation thereby, said striker cam having a plurality of circumferentially spaced outwardly extending shoulders, and a cam follower striker arm having one end rigidly attached to the lower cover plate and the opposite end thereof being disposed under spring load pressure against the striker cam Surface whereby rotation of the striker cam causes cooperation between the shoulders and the striker arm for emitting a tapping sound, said tapping sound being conducted through the bottom hole instrumentation housing means into the well tubing and along the length of said tubing to the surface of the well, said tapping sound having a frequency which is a function of the fluid reservoir pressure.

3. In combination with an oil well bore having well tubing extending therein, a bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of said oil well bore, comprising self-contained bottom hole instrumentation means substantially permanently installed in the well bore in the proximity of the bottom of the well tubing, said bottom hole instrumentation means comprising pressure and temperature sensing means, and transmitting means operably connected to the sensing means for transmitting pressure and temperature data to the surface of the well;

data receiving and processing means disposed at the surface of the well for receiving the pressure and temperature data from the bottom hole instrumentation and for processing said data, and means operably connected to the processing means for recording and displaying said data, said transmitting means transmitting said pressure and temperature data from the bottom hole instrumentation means to the data receiving and processing means along the well tubing with the said tubing acting as a conductor and wherein the resevoir pressure and temperature sensing means comprises a resistance bridge type pressure transducer having a pressure sensitive element exposed to the fluid resevoir, the resistance value of said element varying as a function of resevoir fluid pressure, means for providing a reference voltage through the said resistance bridge whereby the output voltage of the pressure transducer measured across the bridge is proportional to the resevoir fluid pressure and a resistance bridge type temperature transducer having a temperature sensitive element exposed to the fluid resevoir, the resistance value of said element varying as a function of resevoir fluid temperature, means providing reference voltage through said resistance bridge whereby the output voltage of temperature transducer measured across the bridge is proportional to the resevoir fluid temperature.

4. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 3 wherein the self-contained bottom hole instrumentation means comprises a substantially cylindrical housing means having one end thereof removably secured to the bottom end of the well tubing;

said housing means being compartmentized into an upper transmitting compartment, an electronics compartment disposed beneath the transmitting compartment, a power supply compartment disposed beneath the electronics compartment, and a lower sensor compartment;

insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir;

connection wiring for operably connecting said compartments;

the temperature and pressure sensing means disposed within the sensor compartment;

said sensor compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therethrough for exposure of said elements to the fluid reservoir;

the power supply compartment comprising a self-contained regulated power source for providing electrical power upon command to the other compartments of the housing means;

the electronics compartment comprising a clock timer means for periodic activation of the bottom hole instrumentation means, said clock timer means furnishing a command signal for providing electrical power to the compartments of the housing means and subsequently turning said instrumentation means off, a temperature voltage controlled oscillator operably coNnected to the temperature transducer, a pressure voltage controlled oscillator operably connected to the pressure transducer, a trigger generator, and a multiplexer means;

the output of said temperature controlled oscillator operably connected to the multiplexer, said output being that of a square wave pulse train whose frequency is proportional to the voltage input from the temperature transducer, the output of the pressure voltage controlled oscillator operably connected to the multiplexer, said pressure voltage controlled oscillator output being that of a square wave pulse train whose frequency is proportional to the voltage input from the pressure transducer;

the multiplexer means comprising a flip-flop circuit having one output connected to a temperature gating means and the other output connected to a pressure gating means;

the trigger generator comprising a relaxation oscillator circuit and a driver means, the output of the trigger generator being a square wave pulse which is supplied to the multiplexer means each succeeding pulse changing the state of the flip-flop circuit thereby alternately gating the square wave pulse trains from the pressure and temperature voltage controlled oscillators through the multiplexer means to the transmitting means, said transmitting means disposed within the upper transmitting compartment, and rigidly attached to the upper interior surface of the transmitting compartment, said transmitting means comprising a sound transmission solenoid and a driver amplifier;

said solenoid comprising a coil means and a striker plunger inserted within the coil means whereby the striker plunger will strike the upper interior surface of the transmitting compartment upon the passing of each pulse of the square wave pulse train from the pressure and temperature voltage controlled oscillators through the coil means, said clock timer means periodically activating the bottom hole instrumentation means whereby the pressure and temperature transducers will provide representative voltages to the pressure and temperature voltage controlled oscillators, the output pulse trains of said oscillators being alternately gated through the multiplexer means by the trigger generator to the sound transmission solenoid, each of said pulses causing the solenoid plunger to strike the upper interior surface of the transmitting compartment thereby emitting a tapping sound, said tapping sound being conducted through the bottom hole instrumentation housing means into the well tubing and along the length of said tubing to the surface of the well.

5. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the clock timer means comprises a clock motor, a timing mechanism with rotatable contact arms which upon rotation into closure will provide electrical power from the regulated power source to the sensor compartment components, the electronics compartment and to the transmitting compartment whereby said clock timer means may be preset to periodically provide electrical power for interrogation of the bottom hole instrumentation means for temperature and pressure measurements and for transmission of the data to the well surface and to subsequently turn said bottom hole instrumentation means off.

6. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 5 wherein the self-contained regulated power source comprises a nuclear power supply and wherein the data receiving means at the surface of the well comprises a contact microphone removably secured to the upper extremity of the well tubing for receiving temperature and pressure sonic data from the bottom hole instrumentation means, said data being conducted along the well tubing to the surface, a preamplifier for amplifying the received data, a feed back inverter amplifier for further amplifying and inverting the received data at the output of said feed baCk amplifier being operably connected to the processing means, and wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter means;

the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulse in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter means, said pulse meter means comprising an inverter drive amplifier for inverting and amplifying the pulse train and a pulse meter which converts the pulse train into a direct scale meter deflection, the magnitude of the said meter deflection being a function of the frequency of the pulse train whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded.

7. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 6 wherein the cylindrical housing means comprises an elongated cylindrical housing open at one end, the opposite end thereof being removably secured to the bottom end of the well tubing, a cover plate removably secured to the open end of said housing, sealing means interposed between the cover plate and the cylindrical housing, said housing being longitudinally compartmentized, each compartment being separated from the adjacent compartment by a partition plate rigidly secured to the inner walls of the cylindrical housing, each partition plate being provided with a vertically disposed passageway for the journalling of connection wiring therethrough.

8. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 7 wherein, in addition a thermocouple refrigerator is disposed within the electronics compartment, said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

9. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 5 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures, and wherein the data receiving means at the surface of the well comprises a contact microphone removably secured to the upper extremity of the well tubing for receiving temperature and pressure sonic data from the bottom hole instrumentation means, said data being conducted along the well tubing to the surface, a preamplifier for amplifying the received data, a feed back inverter amplifier for further amplifying and inverting the received data, the output of said feed back amplifier being operably connected to the processing means, wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter means, the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train, the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulses in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter means, said pulse meter means comprising an inverter driver amplifier for inverting and amplifying the pulse train and a pulse meter which converts the pulse train into a direct scale meter deflection, the magnitude of the said meter deflection being a function of the frequency of the pulse train whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded;

and wherein the cylindrical housing means comprises a plurality of cylindrical segments, each segment providing housing for each separate compartment, the cross-sectional diameter of each cylindrical segment being smaller than the inside diameter of the well tubing for journalling the bottom hole instrumentation means within said tubing to the bottom of the oil well bore;

the upper most cylindrical segment housing for the transmitting compartment comprising a cylindrical housing member opened at one end, the opposite end thereof disposed within the lower extremity of the well tubing, an outwardly thrusting locking means secured to the exterior of the upper housing member and operably engagable with the inside walls of the well tubing for remotely locking said upper cylindrical member into a desired vertical position within the well tubing, a cover plate removably secured to the open end of said cylindrical member, sealing means interposed between the cylindrical member and cover plate, said cover plate comprising a plate member, a centrally disposed outwardly extending sleeve rigidly secured thereto, said plate member being provided with a centrally disposed bore in alignment with the outwardly extending sleeve;

the electronics compartment housing disposed beneath the transmitting compartment, said electronics compartment housing comprising a cylindrical member open at each end, an upper cover plate removably secured to one end of said cylindrical member, said upper cover plate being substantially identical to that of the aforementioned transmitting compartment cover plate and the electronics cylindrical member, a lower cover plate removably secured to the opposite end of said cylindrical member, said lower cover plate being substantially identical to the aforementioned upper cover plate and oppositely disposed thereto, sealing means interposed between the lower cover plate and the cylindrical member, insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir, a wiring cable operably connected at one end of the transmitting means, the opposite end of said cable being journalled through the bore and sleeve of the transmitting compartment cover plate, through the sleeve and bore of the electronics compartment upper cover plate to the interior of the electronics compartment, an insulation sleeve surrounding the wiring cable between the transmitting compartment and electronics compartment, the extremities of said sleeve being journalled over the outwardly extending sleeves of the transmitting compartment cover plate and the electronics compartment upper cover plate, support strap means secured between the transmitting compartment and the electronics compartment for supporting the weight of the lower compartments, a lower combined sensing and power source compartment comprising a cylindrical member opened at each end, an upper cover plate removably secured to the upper end of said cylindrical member, the upper cover plate being substantially identical to the aforementioned electronics compartment lower cover plate and oppositely disposed thereto, sealing means interposed between the upper cover plate and the cylindrical member, a lower cover plate removably secured to the opposite end of the cylindrical member, sealing means interposed between the lower cover plate and the cylindrical means, said sensor and power source compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therein for exposure of said elements to the fluid reservoir, a wiring cable operably connecting the electronics compartment with the sensing and power source compartment, said cable being journalled through the bore and outwardly extending sleEve of the electronics compartment lower cover plate through the sleeve and bore of the sensing and power source compartment upper cover plate, an insulation sleeve surrounding said wiring cable between the two compartments the extremities of said insulation sleeve being journalled over the outwardly extending sleeve of the electronics compartment lower cover plate and the sensing and power source compartment upper cover plate, support strap means secured between the electronics compartment and the sensing and power source compartment for supporting the weight of the sensing and power source compartment.

10. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 9 wherein, in addition a thermocouple refrigerator is disposed within the electronics compartment, said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

11. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures.

12. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the self-contained regulated power source comprises a nuclear power supply.

13. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the self-contained regulated power source comprises at least one high temperature solid state battery.

14. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the data receiving means at the surface of the well comprises a contact microphone removably secured to the upper extremity of the well tubing for receiving temperature and pressure sonic data from the bottom hole instrumentation means, said data being conducted along the well tubing to the surface, a preamplifier for amplifying the received data, and a feed back inverter amplifier for further amplifying and inverting the received data the output of said feed back amplifier being operably connected to the processing means.

15. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 4 wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter and recorder means;

the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulses in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter recorder means, said pulse meter recorder means comprising an inverter driver amplifier for inverting and amplifying the pulse train, a pulse meter which converts the pulse train into a direct scale meter deflection the magnitude of the said meter deflection being a function of the frequency of the pulse train recorder whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded.

16. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 3 wherein the self-contained bottom hole instrumentation means comprises a substantially cylindrical housing means, an upwardly extending cylindrical coil housing member longItudinally disposed on one end of said housing means said cylindrical coil housing member being slidably disposed within the bottom end of the well tubing, said coil housing member having a centrally disposed annular groove around the outer periphery thereof, the cylindrical housing means being compartmentized into an electronics compartment disposed beneath the coil housing member, a power supply compartment disposed beneath the electronics compartment, and a lower sensor compartment;

insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir, connection wiring for operably connecting said compartments;

the temperature and pressure sensing means disposed within the sensor compartment;

said sensor compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therethrough for exposure of said elements to the fluid reservoir;

the power supply compartment comprising a self-contained regulated power source for providing electrical power upon command to the other compartments of the housing means;

the electronics compartment comprising a clock timer means for periodic activation of the bottom hole instrumentation means, said clock timer means furnishing a command signal for providing electrical power to the compartments of the housing means and subsequently turning said instrumentation means off, a temperature voltage controlled oscillator operably connected to the temperature transducer, a pressure voltage controlled oscillator operably connected to the pressure transducer, a trigger generator, and a multiplexer means;

the output of said temperature controlled oscillator operably connected to the multiplexer;

said output being that of a square wave pulse train whose frequency is proportional to the voltage input from the temperature transducer, the output of the pressure voltage controlled oscillator operably connected to the multiplexer, said pressure voltage controlled oscillator output being that of a square wave pulse train whose frequency is proportional to the voltage input from the pressure transducer;

the multiplexer means comprising a flip-flop circuit having one output connected to a pressure gating means;

the trigger generator comprising a relaxation oscillator circuit and a driver means, the output of the trigger generator being a square wave pulse which is supplied to the multiplexer means, each succeeding pulse changing the state of the flip-flop circuit thereby alternately gating the square wave pulse trains from the pressure and temperature voltage controlled oscillators through the multiplexer means to the transmitting means, said transmitting means comprising a coil drive oscillator disposed within the electronics compartment and operably connected to the output of the multiplexer, a transmission coil disposed within the annular groove around the outer periphery of the coil housing member and in engagement with the inner walls of the well tubing, sealing means interposed between the coil housing member and the inner walls of the well tubing both above and below the annular groove, said transmission coil being operably connected to the output of the coil drive oscillator whereby the pressure and temperature transducers will provide representative voltages to the pressure and temperature voltage controlled oscillators, the output pulse trains of said oscillators being alternately gated through the multiplexer means by the trigger generator to the coil drive oscillator, each of said pulses keying the coil drive oscillator on and off to provide a pulsing current through the transmission coil thereby gating upon alternating magnetic lines of flux which intersect the walls of the well tubing and are conducted along the length of said tubing to the surface of the well.

17. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the clock timer means comprises a clock motor, a timing mechanism with rotatable clock arms which upon rotation into closure will provide electrical power from the regulated power source to the sensor compartment components, the electronics compartment and to the transmitting compartment whereby said clock timer means may be preset to periodically provide electrical power for the interrogation of the bottom hole instrumentation means for temperature and pressure measurements and for transmission of the data to the well surface and to subsequently turn said bottom hole instrumentation means off.

18. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 17 wherein the self-contained regulated power source comprises a nuclear power supply and wherein the data receiving means at the surface of the well comprises an annular coil housing slidably disposed around the outer periphery of the well tubing, a receiving coil disposed within said annular coil housing for inductively receiving the magnetic flux temperature and pressure data from the bottom hole instrumentation means, a preamplifier for amplifying the received data, and a feed-back inverter amplifier for further amplifying and inverting the received data, the output of said feed-back amplifier being operably connected to the processing means and wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter means;

the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train, the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulses in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter means, said pulse meter means comprising an inverter drive amplifier for inverting and amplifying the pulse train and a pulse meter which converts the pulse train into a direct scale meter deflection, the magnitude of the said meter deflection being a function of the frequency of the pulse train whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded.

19. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 18 wherein the cylindrical housing means comprises an elongated cylindrical housing open at one end, a cover plate removably secured to the open end of said housing, sealing means interposed between the cover plate and the cylindrical housing, said housing being longitudinally compartmentized, each compartment being separated from the adjacent compartment by a partition plate rigidly secured to the inner walls of the cylindrical housing, each partition plate being provided with a vertically disposed passageway for the journalling of connection wiring therethrough.

20. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 19 wherein, in addition a thermocouple refrigerator is disposed within the electronics compartment, said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

21. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 17 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures, and wherein the data receiving means at the surface of the well comprises an annular coil housing slidably disposed around the oUter periphery of the well tubing, a receiving coil disposed within said annular coil housing for inductively receiving the magnetic flux temperature and pressure data from the bottom hole instrumentation means, a preamplifier for amplifying the received data, and a feed-back inverter amplifier for further amplifying and inverting the received data, the output of said feed-back amplifier being operably connected to the processing means, and wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter means;

the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train, the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulses in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter means, said pulse meter means comprising an inverter driver amplifier for inverting and amplifying the pulse train and a pulse meter which converts the pulse train into a direct scale meter deflection, the magnitude of the said meter deflection being a function of the frequency of the pulse train whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded, and wherein the cylindrical housing means comprises a plurality of cylindrical segments, each segment providing housing for each separate compartment, the cross-sectional diameter of each cylindrical segment being smaller than the inside diameter of the well tubing for journalling the bottom hole instrumentation means within said tubing to the bottom of the oil well bore;

the upper cylindrical segment housing comprising the aforementioned cylindrical coil housing member, an outwardly thrusting locking means secured to the exterior of the coil housing member and operably engagable with the inside walls of the well tubing for remotely locking said coil housing member into a desired vertical position within the well tubing, a centrally disposed outwardly extending sleeve secured to the bottom end of the cylindrical coil housing member said housing member being provided with a centrally disposed bore in alignment with the outwardly extending sleeve and in open communication with the annular groove;

the electronics compartment housing disposed beneath the coil housing member, said electronics compartment housing comprising a cylindrical member open at each end, an upper cover plate removably secured to one end of said cylindrical member, sealing means interposed between the cylindrical member and the upper cover plate, said cover plate comprising a plate member, a centrally disposed outwardly extending sleeve rigidly secured thereto, said plate member being provided with a centrally disposed bore in alignment with the outwardly extending sleeve, a lower cover plate removably secured to the opposite end of said cylindrical member said lower cover plate being substantially identical to the afore mentioned upper cover plate and oppositely disposed thereto, sealing means interposed between the lower cover plate and the cylindrical member, insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir, a wiring cable operably connected at one end to the transmission coil, the opposite end of said cable being journalled through the bore and sleeve of the coil housing member, through the sleeve and bore of the electronics compartment upper cover plate to the interior of the electronics compartment, an insulation sleeve surrounding the wiring cable between the coil housing member and the electronics compartment, the extremities of said sleeve being journalled over the outwardly extending sLeeves of the coil housing member and the electronics compartment upper cover plate, support strap means secured between the coil housing member and the electronics compartment for supporting the weight of the lower compartments;

a lower combined sensing and power source compartment disposed beneath the electronics compartment said sensing and power source compartment comprising a cylindrical member open at each end, an upper cover plate removably secured to the upper end of said cylindrical member, the upper cover plate being substantially identical to the aforementioned electronics compartment lower cover plate and oppositely disposed thereto, sealing means interposed between the upper cover plate and the cylindrical member, a lower cover plate removably secured to the opposite end of the cylindrical member, sealing means interposed between the lower cover plate and the cylindrical means, said sensor and power source compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therein for exposure of said elements to the fluid reservoir, a wiring cable operably connecting the electronics compartment with the sensing and power source compartment, said cable being journalled through the bore and outwardly extending sleeve of the electronics compartment lower cover plate through the sleeve and bore of the sensing and power source upper cover plate, an insulation sleeve surrounding said wiring cable between the two compartments, the extremities of said insulation sleeve being journalled over the outwardly extending sleeve of the electronics compartment lower cover plate and the sensing and power source compartment upper cover plate, support strap means secured between the electronics compartment and the sensing and power source compartment for supporting the weight of the said sensing and power source compartment.

22. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 21 wherein, in addition a thermocouple refrigerator is disposed within the electronics compartment, said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

23. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures.

24. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the self-contained regulated power source comprises a nuclear power supply.

25. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the self-contained regulated power source comprises at least one high temperature solid state battery.

26. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the data receiving means at the surface of the well comprises an annular coil housing slidably disposed around the outer periphery of the well tubing, a receiving coil disposed within said annular coil housing for inductively receiving the magnetic flux temperature and pressure data from the bottom hole instrumentation means, a preamplifier for amplifying the received data, and a feed-back inverter amplifier for further amplifying and inverting the received data, the output of the said feed-back amplifier being operably connected to the processing means.

27. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 16 wherein the processing means disposed at the surface of the well is operably connected To the output of the receiving means and comprises a pulse conditioner, a pulse monostable circuit and a pulse meter means;

the pulse conditioner comprising a pulse shaping inverter for inverting and squaring up each pulse of the received pulse train, the output of the pulse conditioner connected to the pulse monostable circuit which further conditions the pulse train by again inverting and making uniform the duty cycle of the pulses in said pulse train, the output of the monostable circuit being a constant width pulse train operably connected to the pulse meter means, said pulse meter means comprising an inverter driver amplifier for inverting and amplifying the pulse train and a pulse meter which converts the pulse train into a direct scale meter deflection, the magnitude of the said meter deflection being a function of the frequency of the pulse train whereby the bottom hole fluid reservoir pressure and temperature may be alternately displayed and recorded.

28. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 3 wherein the self-contained bottom hole instrumentation means comprises a substantially cylindrical housing means having one end thereof removably secured to the bottom end of the well tubing, said housing means being compartmentized into an upper transmitting compartment, an electronics compartment disposed beneath the transmitting compartment, a power supply compartment disposed beneath the electronics compartment, and a lower sensing compartment, insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir, connection wiring for operably connecting said compartments;

the temperature and pressure sensing means disposed within the sensor compartment, said sensor compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therethrough for exposure of said elements to the fluid reservoir, the power supply compartment comprising a self-contained regulated power source for providing electrical power upon command to the other compartments of the housing means;

the electronics compartment comprising a bottom hole instrumentation interrogation means for providing electrical power to the compartments of the housing means, a timer means for subsequently turning said instrumentation off, a multiplexer means operably connected to the outputs of the temperature and pressure transducers for alternately passing the representative temperature and pressure voltages therethrough upon command, an analog to digital (A-D) converter whose input is operably connected with the output of the multiplexer means for alternately converting the input representative temperature and pressure voltages to a multibit binary number which is representative of said input voltages, a clock pulser operably connected to the A-D converter for serially shifting the binary number out of said converter, an oscillator bank comprising five oscillators, each oscillator set at a different output frequency thereby establishing five data and command channels, the binary number output of the A-D converter being used to key two of the oscillators of the oscillator bank, the pulses representing '"'"''"'"''"'"''"'"'1'"'"''"'"''"'"''"'"' keying a first oscillator, the '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' levels being inverted in a parallel output circuit keying the second oscillator thereby converting said binary number into a dual frequency code, a mixer driver operably connected to the output of the oscillator bank for mixing the outputs of the five oscillators, the output of said mixer driver being amplitude modulated on an ultrasonic carrier frequency whereby upon compression of the analog to digital conversion of a pressure measurement, an end-of-conversion pulse is provided by the A-D converter to the multiplexer, changing the state of said multiplexer thereby allowiNg the representative temperature voltage to pass through the multiplexer, to the A-D converter, simultaneously said multiplexer providing a pressure load command to a third oscillator of the oscillator bank for subsequent transmission to the well surface, and upon compression of the temperature conversion said multiplexer likewise providing a temperature load command to a fourth oscillator of the oscillator bank, a clock pulser also providing continuous synchronizing pulses to a fifth oscillator of the oscillator bank, a transmitting means disposed within the transmitting compartment and rigidly attached to the upper interior surface of the transmitting compartment said transmitting means comprising an ultrasonic transmitter operably connected to the output of the mixer driver, the ultrasonic output of said transmitter being conducted through the bottom hole instrumentation housing means into the well tubing and along the length of said tubing to the surface of the well.

29. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the interrogation means comprises an ultrasonic receiver disposed within the transmitting compartment and rigidly secured to the upper surface thereof for receiving an ultrasonic interrogation command signal from the well surface, said command signal being transmitted downwardly along the well tubing to the bottom hole instrumentation means, a tuned amplifier disposed within the electronics compartment and operably connected with the ultrasonic receiver for amplifying said command signals, the output of the said tuned amplifier being used to start the turn-off timer means and also to activate the bottom hole instrumentation means through the power control relay.

30. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 29 wherein the self-contained regulated power source comprises a nuclear power supply and wherein the data receiving means at the surface of the well comprises an ultrasonic receiver removably secured to the upper extremity of the well tubing at the surface of the well for receiving the demodulated ultrasonic data from the bottom hole instrumentation means, said data being conducted along the well tubing to the surface of the well and wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a discriminator bank, a shift register, gating means, and a holding register means;

said discriminator bank comprising five filter means whose frequency passing characteristics correspond to the output frequencies of the five aforementioned oscillators of the bottom hole instrumentation oscillator bank and five buffers, one for each filter for conditioning the output pulses from each of said filters, the first and second filter passing in pulses representing '"'"''"'"''"'"''"'"'1'"'"''"'"''"'"''"'"' and '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' of the binary number of the received data for input to the shift register, the third filter passing the pressure load command for input to the gating means, the fourth filter passing the temperature load command for input to the gate means and the fifth filter for passing the continuous synchronizing pulses from the bottom hole instrumentation clock pulse, the output from the said fifth filter and buffer being operably connected to the output of the shift register and synchronizing the serial entry of the binary number therein;

the gating means comprising a temperature gating means, and a pressure gating means, said gating means operably connected to the output of the shift register and to the input of the holding register means, said holding register means comprising a temperature holding register and a pressure holding register whereby the receipt of a pressure load command signal from the bottom hold instrumentation means will enable the pressure gating means thereby gating a pressure binary number in The shift register into the pressure holding register for display and recording purposes and also clearing said shift register for the receipt of a temperature binary number where again after entry of the temperature binary number the receipt of a temperature load command signal will gate said temperature binary number out of the shift register and into the temperature holding register for display and recording.

31. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 30 wherein the cylindrical housing means comprises an elongated cylindrical housing open at one end, the opposite end thereof being removably secured to the bottom end of the well tubing, a cover plate removably secured to the open end of said housing, sealing means interposed between the cover plate and the cylindrical housing, said housing being longitudinally compartmentized, each compartment being separated from the adjacent compartment by a partition plate rigidly secured to the inner walls of the cylindrical housing, each partition plate being provided with a vertically disposed passageway for the journalling of connection wiring therethrough.

32. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 31 wherein, in addition, a thermocouple refrigerator is disposed within the electronics compartment said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

33. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 29 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures and wherein the data receiving means at the surface of the well comprises an ultrasonic receiver removably secured to the upper extremity of the well tubing at the surface of the well for receiving the demodulated ultrasonic data from the bottom hole instrumentation means, said data being conducted along the well tubing to the surface of the well, and wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a discriminator bank, a shift register, gating means, and a holding register means;

said discriminator bank comprising five filter means whose frequency passing characteristics correspond to the output frequencies of the five aforementioned oscillators of the bottom hole instrumentation oscillator bank and five buffers, one for each filter for conditioning the output pulses from each of said filters, the first and second filters passing in pulses representing '"'"''"'"''"'"''"'"'1'"'"''"'"''"'"''"'"' and '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' of the binary number of the received data for input to the shift register, the third filter passing the pressure load command for input to the gating means, the fourth filter passing the temperature load command for input to the gating means and the fifth filter for passing the continuous synchronizing pulses from the bottom hole instrumentation clock pulse, the output from said fifth filter and buffer being operably connected to the shift register and synchronizing the serial entry of the binary number therein;

the gating means comprising a temperature gating means, and a pressure gating means, said gating means operably connected to the output of the shift register and to the input of the holding register means said holding register means comprising a temperature holding register and a pressure holding register whereby the receipt of a pressure load command signal from the bottom hole instrumentation means will enable the pressure gating means thereby gating a pressure binary number in the shift register into the pressure holding register for display and recording purposes and also clearing said shift register for tHe receipt of a temperature binary number where again after entry of the temperature binary number the receipt of a temperature load command signal will gate said temperature binary number out of the shift register and into the temperature holding register for display and recording and wherein the cylindrical housing means comprises a plurality of cylindrical segments, each segment providing housing for each separate compartment, the cross-sectional diameter of each cylindrical segment being smaller than the inside diameter of the well tubing for journalling the bottom hole instrumentation means within said tubing to the bottom of the oil well bore;

the uppermost cylindrical segment housing for the transmitting compartment comprising a cylindrical housing member opened at one end, the opposite end thereof disposed within the lower extremity of the well tubing, an outwardly thrusting locking means secured to the exterior of the upper housing member and operably engagable with the inside walls of the well tubing for remotely locking said upper cylindrical member into a desired vertical position within the well tubing, a cover plate removably secured to the open end of said cylindrical member, sealing means interposed between the cylindrical member and cover plate, said cover plate comprising a plate member a centrally disposed outwardly extending sleeve rigidly secured thereto, said plate member being provided with a centrally disposed bore in alignment with the outwardly extending sleeve;

the electronics compartment housing disposed beneath the transmitting compartment, said electronics compartment housing comprising a cylindrical member open at each end, an upper cover plate removably secured to one end of said cylindrical member, said upper cover plate being substantially identical to that of the aforementioned transmitting compartment cover plate and oppositely disposed thereto, sealing means between the upper cover plate and the electronics cylindrical member, a lower cover plate removably secured to the opposite end of said cylindrical member said lower cover plate being substantially identical to the aforementioned upper cover plate and oppositely disposed thereto, sealing means interposed between the lower cover plate and the cylindrical member, insulation material disposed on the interior walls of the electronics compartment for prevention of a rapid temperature increase upon installation of the housing means into the fluid reservoir, a wiring cable operably connected at one end to the transmitting means, the opposite end of said cable being journalled through the bore and sleeve of the transmitting compartment cover plate, through the sleeve and bore of the electronics compartment upper cover plate to the interior of the electronics compartment, an insulation sleeve surrounding the wiring cable between the transmitting compartment and electronics compartment, the extremities of said sleeve being journalled over the outwardly extending sleeve of the transmitting compartment cover plate and the electronics compartment for supporting the weight of the lower compartments, a lower combined sensing and power source compartment disposed beneath the electronics compartment said sensing and power source compartment comprising a cylindrical member opened at each end, an upper cover plate removably secured to the upper end of said cylindrical member, the upper cover plate being substantially identical to the aforementioned electronics compartment lower cover plate and oppositely disposed thereto, sealing means interposed between the upper cover plate and the cylindrical member, a lower cover plate removably secured to the opposite end of the cylindrical member, sealing means interposed between the lower cover plate and the cylindrical means, said sensor and power source compartment being provided with ports through the housing means for journalling the pressure and temperature sensitive elements therein for exposure of said elements to the fluid reservoir, a wiring cable operably connEcting the electronics compartment with the sensing and power source compartment, said cable being journalled through the bore and outwardly extending sleeve of the electronics compartment lower cover plate through the sleeve and bore of the sensing and power source compartment upper cover plate, an insulation sleeve surrounding said wiring cable between the two compartments the extremities of said insulation sleeve being journalled over the outwardly extending sleeve of the electronics compartment lower cover plate and the sensing and power source compartment upper cover plate, support strap means secured between the electronics compartment and the sensing and power source compartment.

34. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 33 wherein, in addition, a thermocouple refrigerator is disposed within the electronics compartment, said refrigerator being continuously powered by a regulated power source for the protection of the electronics compartment in high temperature wells.

35. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the self-contained regulated power source comprises at least one dry cell battery constructed to withstand high oil well reservoir temperatures.

36. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the self-contained regulated power source comprises at least one high temperature solid state battery.

37. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the self-contained regulated power source comprises a nuclear power supply.

38. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the data receiving means at the surface of the well comprises an ultrasonic receiver removably secured to the upper extremity of the well tubing at the surface of the well for receiving the demodulated ultrasonic data from the bottom hole instrumentation means said data being conducted along the well tubing to the surface of the well.

39. A bottom hole indicator for measuring the fluid reservoir pressure and temperature at the bottom of an oil well bore as set forth in claim 28 wherein the processing means disposed at the surface of the well is operably connected to the output of the receiving means and comprises a discriminator bank, a shift register, gating means, and a holding register means;

said discriminator bank comprising five filter means whose frequency passing characteristics correspond to the output frequencies of the five aforementioned oscillators of the bottom hole instrumentation oscillator bank and five buffers, one for each filter for conditioning the output pulses from each of said filter, the first and second filter passing in pulses representing the '"'"''"'"''"'"''"'"'1'"'"''"'"''"'"''"'"' and '"'"''"'"''"'"''"'"'0'"'"''"'"''"'"''"'"' of the binary number of the received data for input to the shift register, the third filter passing the pressure load command for input to the gating means, the fourth filter passing the pressure load command for input to the gating means and the fifth filter for passing continuous synchronizing pulses from the bottom hole instrumentation clock pulser, the output from said fifth filter and buffer being operably connected to the shift register and synchronizing the serial entry of the binary number therein;

the gating means comprising a temperature gating means, and a pressure gating means, said gating means operably connected to the output of the shift register and to the input of the holding register means said holding register means comprising a temperature holding register and a pressure holding register whereby the receipt of a pressure load command signal fRom the bottom hole instrumentation means will enable the pressure gating means thereby gating a pressure binary number in the shift register into the pressure holding register for display and recording purposes and also clearing said shift register for the receipt of a temperature binary number where again after entry of the temperature binary number the receipt of a temperature load command signal will gate said temperature binary number out of the shift register and into the temperature holding register for display and recording.