A miniaturized downhole temperature and pressure measurer resistant to ultra-high temperature and ultra-high pressure

Abstract

The present invention relates to the technical field of temperature and pressure measurement, and particularly to a miniaturized downhole temperature and pressure measurer resistant to ultra-high temperature and ultra-high pressure, comprising: a bullet-shaped encapsulation housing, which is formed by casting liquid polydimethylsiloxane and includes a bullet-shaped end face; a polytetrafluoroethylene aerogel layer and a control circuit board are arranged inside the bullet-shaped encapsulation housing, and the polytetrafluoroethylene aerogel layer wraps the control circuit board; a porous conductive PDMS pressure sensing module is arranged on the outer surface of the bullet-shaped encapsulation housing, and the porous conductive PDMS pressure sensing module is connected to the control circuit board; the temperature and pressure measurer further includes a thermocouple, the cold end of the thermocouple is connected to the control circuit board, and the hot end of the thermocouple extends to the bullet-shaped end face and protrudes from the bullet-shaped end face. The present invention can realize rapid, continuous and low-cost measurement of the wellbore temperature field and pressure field during the whole drilling and completion process, has strong tolerance to the downhole high-temperature and high-pressure environment, and effectively makes up for the deficiencies in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature and pressure measurement, especially to the measurement of the wellbore pressure field and temperature field in oil and gas drilling and completion and gas hydrate drilling and production. In particular, it refers to a miniaturized downhole temperature and pressure measuring device resistant to ultra-high temperature and ultra-high pressure. Background Technique

[0002] With the continuous deepening of exploration and development, the target well depth faced by drilling and completion engineering shows a continuous growth trend. The geological conditions of oil and gas reservoirs are becoming more and more complex, and risk control is also becoming more important for the drilling and completion process. Complex downhole environments, especially problems such as narrow safety density windows, lead to frequent occurrences of complex situations such as leakage, well kick, and channeling during drilling and completion, damaging the integrity of the wellbore and even potentially resulting in the abandonment of oil and gas wells.

[0003] Temperature and pressure are important parameters affecting fluid physical properties. The density and rheological parameters of fluids under different temperature conditions will change compared with the measured values in the ground environment. Especially for the development of gas hydrates, temperature is a sensitive factor. At non-low temperature conditions of 0°C - 15°C, gas hydrates are very unstable and have high requirements for pressure control conditions. For the fluid in the wellbore, or even more specifically for each fluid microelement in the wellbore, temperature affects the pressure change in each fluid microelement, and thus affects the pressure distribution of the entire flow field in the wellbore. And timely and accurate measurement of pressure is of great significance for ensuring safe operation and avoiding accidents such as "well kick" and "well leakage". Therefore, obtaining accurate temperature and pressure distributions in the wellbore is of great significance for calculating, judging, and controlling the properties of downhole fluids and the risks of the construction process during drilling and completion.

[0004] With the long-term development of measurement-while-drilling technology, a series of mature products have been formed, achieving remarkable application effects. However, for some currently mainly used measurement-while-drilling formation pressure measurement instruments, the basic principle is to install sensors in the bottom hole assembly near the drill bit to measure the formation temperature information near the drill bit. Due to the existence of some objective limitations in existing tools, they cannot be fully applied throughout the drilling and completion process.

[0005] First of all, most of the currently applied measurement-while-drilling tools have relatively high costs. Once a complex accident occurs downhole, it may lead to the scrapping of the equipment, increasing the drilling economic cost.

[0006] Secondly, most of the current parameter measurements are mainly focused on the area near the drill bit, which is the measurement of the wellbore vertex, lacking a three-dimensional full-process measurement of the temperature gradient change of the entire wellbore.

[0007] Thirdly, most of the current measurement-while-drilling tools are applied to the parameter measurement during the drilling process and rarely pay attention to the completion process.

[0008] With the further deepening of oil and gas resource exploration, both the drilling and completion processes are equally faced with risks and challenges. The drilling and completion process not only determines whether to continue drilling, but also affects the lifespan of the oil and gas well and the recovery rate of the oil and gas reservoir. Therefore, the three-dimensional detection of wellbore temperature and pressure throughout the drilling and completion process becomes particularly important. The accurate acquisition of downhole temperature and pressure data can effectively avoid complications, ensure the quality of oil and gas wells, and achieve safe and reliable drilling and completion operations.

[0009] Although the miniaturized downhole temperature and pressure sensors have been continuously improved and upgraded, their current measurement ranges are generally resistant to temperatures of 125°C and pressures of about 100 MPa, which limits the application of such tools in extreme downhole temperature and pressure environments such as deep wells and ultra-deep wells. Summary of the Invention

[0010] To solve the technical problem in the prior art that the measurement range of the miniaturized downhole temperature and pressure sensors is limited and it is difficult to measure the temperature and pressure in extreme downhole environments such as deep wells and ultra-deep wells, an embodiment of the present invention provides a miniaturized downhole temperature and pressure sensor resistant to ultra-high temperature and ultra-high pressure. The temperature and pressure sensor includes: a bullet-shaped encapsulation housing, which is formed by casting liquid polydimethylsiloxane and includes a bullet-shaped end face.

[0011] A polytetrafluoroethylene aerogel layer and a control circuit board are arranged inside the bullet-shaped encapsulation housing, and the polytetrafluoroethylene aerogel layer wraps the control circuit board.

[0012] A porous conductive PDMS pressure sensing module is arranged on the outer surface of the bullet-shaped encapsulation housing, and the porous conductive PDMS pressure sensing module is connected to the control circuit board.

[0013] The temperature and pressure sensor further includes a thermocouple. The cold end of the thermocouple is connected to the control circuit board, and the hot end of the thermocouple extends to and protrudes from the bullet-shaped end face.

[0014] In a preferred embodiment, the temperature and pressure sensor further includes a battery module, and the polytetrafluoroethylene aerogel layer wraps the battery module.

[0015] In a preferred embodiment, the control circuit board is parallel to the end face of the hot end of the thermocouple.

[0016] In a preferred embodiment, an MCU module, a pressure measurement module, a temperature measurement module, and a power supply module are integrated on the control circuit board. The MCU module includes a minimum system.

[0017] Among them, the pressure measurement module includes a high-precision pressure sensor circuit, a high-precision ADC circuit, and a low-precision pressure sensor circuit.

[0018] The high-precision pressure sensor circuit includes a first Wheatstone bridge and a first operational amplifier. The low-precision pressure sensor circuit includes a second Wheatstone bridge and a second operational amplifier. The first Wheatstone bridge and the second Wheatstone bridge are connected to a porous conductive PDMS pressure sensing module disposed on the outer surface of the bullet-shaped encapsulation housing.

[0019] Among them, the high-precision pressure sensor circuit performs analog-to-digital conversion through the high-precision ADC circuit and communicates with the MCU module.

[0020] The low-precision pressure sensor circuit communicates with the MCU module through the ADC circuit built in the MCU module.

[0021] The temperature measurement module includes a temperature sensor circuit. The temperature sensor circuit includes a third operational amplifier. The third operational amplifier is connected to the cold end of the thermocouple.

[0022] In a preferred embodiment, the input end of the first operational amplifier is connected to the first Wheatstone bridge, the output end of the first operational amplifier is connected to the high-precision ADC circuit, and the high-precision ADC circuit communicates with the MCU module in an I2C communication manner.

[0023] In a preferred embodiment, the input end of the second operational amplifier is connected to the second Wheatstone bridge, and the output end of the second operational amplifier is connected to the ADC circuit built in the MCU module.

[0024] In a preferred embodiment, the input end of the third operational amplifier is connected to the cold end of the thermocouple, and the output end of the third operational amplifier is connected to the ADC circuit built in the MCU module.

[0025] In a preferred embodiment, the MCU module further includes a high-speed crystal oscillator and a low-speed crystal oscillator.

[0026] In a preferred embodiment, the power supply module includes a power circuit, a battery interface, and a power filter circuit.

[0027] The power circuit is used to generate a fixed regulated output voltage of 3.3V within a wide input voltage range, and the battery interface is connected to the battery module.

[0028] The power filter circuit is configured with a chip capacitor to filter out high and low frequency noises in the power circuit.

[0029] In a preferred embodiment, an SWD interface and a serial communication interface are also integrated on the control circuit board.

[0030] The beneficial effects brought by the technical solution provided by the embodiment of the present invention at least include:

[0031] The present invention proposes a miniaturized downhole temperature and pressure measuring device that is resistant to ultra-high temperature and ultra-high pressure, which can realize fast, continuous and low-cost measurement of the wellbore temperature field and pressure field during the entire drilling and completion process. The present invention is smart and simple in design, low in cost, easy to use, can perform continuous measurement on the entire wellbore, has strong tolerance to the underground high temperature and high pressure environment, and effectively makes up for the deficiencies in the existing technology.

[0032] The present invention proposes a miniaturized downhole temperature and pressure measuring device resistant to ultra-high temperature and ultra-high pressure, which adopts a porous conductive PDMS pressure sensing module and a thermocouple to respectively detect the wellbore pressure and temperature values, adopts a polytetrafluoroethylene aerogel layer to wrap a control circuit board to isolate the temperature, adopts a polydimethylsiloxane material to cast into a bullet-shaped packaging shell, and integrates an MCU module in the control circuit board for data processing, thereby improving the integration of the measuring device, being able to quickly monitor the wellbore pressure and temperature changes during the whole process of drilling and completion, providing technical support for timely understanding of well wall stability, well kick and leakage, so that ground operators can timely adjust the wellbore pressure or change the downhole fluid performance, thereby effectively preventing accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 It is a structural schematic diagram of a miniaturized downhole temperature and pressure measuring device capable of resisting ultra-high temperature and ultra-high pressure according to the present invention.

[0035] Figure 2 It is a cross-sectional schematic diagram of a miniaturized downhole temperature and pressure measuring device resistant to ultra-high temperature and ultra-high pressure according to the present invention.

[0036] Figure 3 The present invention is a control circuit board structure diagram of a miniaturized downhole temperature and pressure measuring device capable of resisting ultra-high temperature and ultra-high pressure. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description and claims of the present invention and the above-mentioned drawings, the terms "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0039] As Figure 1 shown in the schematic structural diagram of a miniaturized downhole temperature and pressure measuring device with ultra-high temperature and ultra-high pressure resistance according to the present invention, Figure 2 shown in the cross-sectional schematic diagram of a miniaturized downhole temperature and pressure measuring device with ultra-high temperature and ultra-high pressure resistance according to the present invention. According to an embodiment of the present invention, there is provided a miniaturized downhole temperature and pressure measuring device with ultra-high temperature and ultra-high pressure resistance (200 °C, 200 MPa), comprising: a bullet-shaped encapsulation housing 1.

[0040] The bullet-shaped encapsulation housing 1 is formed by casting with liquid polydimethylsiloxane (PDMS), so that the bullet-shaped encapsulation housing 1 has characteristics such as heat resistance, cold resistance, waterproofness, and thermal conductivity. The thermal conductivity is 0.134 - 0.159 W / (m·K), and the light transmittance is 100%. It has physiological inertness, good chemical stability, electrical insulation, weather resistance, good hydrophobicity, and high shear resistance, and can be used for a long time at -50 °C to 250 °C.

[0041] The bullet-shaped encapsulation housing 1 has excellent physical properties, can maintain stable performance in a complex wellbore flow field environment, ensure the integrity of the overall bullet-shaped encapsulation housing 1, can well protect the components in the control circuit board 5 from damage, and ensure pressure balance inside and outside the bullet-shaped encapsulation housing 1, improve the compressive strength of the bullet-shaped encapsulation housing 1, and achieve a pressure environment withstanding 200 MPa.

[0042] The bullet-shaped encapsulation housing 1 of the present invention includes a bullet-shaped end face 2, thus forming a bullet-shaped structure, which saves materials for the bullet-shaped encapsulation housing 1 and is beneficial to minimizing the resistance suffered by the bullet-shaped encapsulation housing 1 when flowing in drilling fluid.

[0043] According to an embodiment of the present invention, a polytetrafluoroethylene aerogel layer 6, a control circuit board 5, and a battery module 10 are disposed inside the bullet-shaped encapsulation housing 1, and the polytetrafluoroethylene aerogel layer 6 wraps the control circuit board 5 and the battery module 10. The battery module 10 supplies electrical energy to the control circuit board 5. In some embodiments, the battery module 10 is a button battery.

[0044] Since the battery module 10 is parallel to the control circuit board 5, the maximum size can be approximately the same as the geometric size of the control circuit board 5. Considering that the diameter of the button battery is preferably not more than 15 mm, the Panasonic BR1225A high-temperature resistant button battery is selected for the battery module 10. The operating temperature of the battery is -40 to +125 °C, the rated capacity is 48 mAh, and the external dimensions are: diameter 12 mm, thickness 2.5 mm.

[0045] The thermal coefficient of the polytetrafluoroethylene aerogel layer 6 is 0.27 W / (m·K), which has good heat insulation performance, and can greatly reduce the influence of the components in the control circuit board 5 on the external environmental temperature, ensure the normal operation of the control circuit board 5 at high temperatures, and achieve a temperature environment tolerance of 200 °C.

[0046] According to an embodiment of the present invention, a porous conductive PDMS pressure sensing module 4 is disposed on the outer surface of the bullet-shaped encapsulation housing 1, and the porous conductive PDMS pressure sensing module 4 is connected to the control circuit board 5. The porous conductive PDMS pressure sensing module 4 is used to sense the pressure of the wellbore environment flow field.

[0047] A miniaturized downhole temperature and pressure measuring device with ultra-high temperature and ultra-high pressure resistance provided by the present invention further includes a thermocouple 3. The cold end 9 of the thermocouple 3 is connected to the control circuit board 5, and the hot end 8 of the thermocouple 3 extends to the bullet-shaped end face 2 and protrudes from the bullet-shaped end face 2.

[0048] In the present invention, the hot end 8 of the thermocouple 3 extends to the bullet-shaped end face 2 and protrudes from the bullet-shaped end face 2 to directly contact the outside world, and is used to sense the temperature of the wellbore environment flow field when moving in the wellbore. The cold end 9 of the thermocouple 3 is directly connected to the control circuit board 5. The working characteristics of the thermocouple 3 isolate the temperatures of the hot end 8 and the cold end 9 from each other, thereby avoiding the transmission of external temperature along the thermocouple 3 to the control circuit board 5 and causing failures.

[0049] The control circuit board 5 collects the voltage difference between the cold end 9 and the hot end 8 of the thermocouple 3 through a temperature sensor circuit (described below), and combines the temperature of the cold end 9 of the thermocouple 3 to further calculate the temperature of the hot end 8 of the thermocouple 3, so as to achieve the measurement of the wellbore temperature. For the specific measurement algorithm, those skilled in the art can configure it through the existing measurement algorithms of thermocouples, and will not be elaborated in the embodiments.

[0050] In a preferred embodiment, the control circuit board 5 is parallel to the end face of the hot end 8 of the thermocouple 3 (the thermocouple 3 is perpendicular to the control circuit board 5).

[0051] The outer surface of the bullet-shaped packaging shell 1 is also provided with a data interface 7, and the data interface 7 is connected to the control circuit board 5. In some embodiments, four data interfaces 7 are provided.

[0052] like Figure 3 The figure shows a structural block diagram of a control circuit board of a miniaturized downhole temperature and pressure measuring device resistant to ultra-high temperature and ultra-high pressure of the present invention. According to an embodiment of the present invention, an MCU module 100, a pressure measuring module, a temperature measuring module, a power supply module, a SWD interface 700 and a serial communication interface 900 are integrated on the control circuit board 5.

[0053] MCU module 100

[0054] The MCU module 100 is a single-chip microcomputer (Microcontroller Unit). The MCU module 100 is used to constitute a data processing unit, receive the pressure data and temperature data of the porous conductive PDMS pressure sensing module 4 and the thermocouple 3, receive, store, analyze and transmit the data, perform analog-to-digital conversion, process the received pressure data and temperature data, add time tags to the pressure data and temperature data, store the data in the internal flash memory, send the data in real time, and communicate with the host computer.

[0055] The MCU module 100 includes a minimum system 101 , a high-speed crystal oscillator 102 and a low-speed crystal oscillator 103 .

[0056] Minimum system 101 uses STMicroelectronics' minimum system STM32F412CGU6 or minimum system STM32L4Q5CGU6. STMicroelectronics' minimum system STM32F412CGU6 and minimum system STM32L4Q5CGU6 are both ultra-low power microcontrollers. The difference is that the minimum system STM32F412CGU6 has a built-in ADC circuit (analog-to-digital conversion circuit) of 12 bits and cannot be oversampled, while the minimum system STM32L4Q5CGU6 has a built-in ADC circuit of 12 bits and can be oversampled to 16 bits.

[0057] The number of bits of the ADC circuit of the minimum system 101 directly affects the working accuracy of the temperature sensor circuit 600 and the low-precision pressure sensor circuit 400. Since the packages of the minimum system STM32F412CGU6 and the minimum system STM32L4Q5CGU6 of STMicroelectronics are the same, they can be freely selected and replaced according to actual conditions and budget. In this embodiment, the minimum system 101 uses the minimum system STM32F412CGU6 of STMicroelectronics.

[0058] In addition, the STM32F412CGU6 and STM32L4Q5CGU6 minimum systems of STMicroelectronics support all ARM (Advanced RISC Machine, ARM processor) single-precision data processing instructions and data types, implement a complete DSP (Digital Signal Processing) instruction set, and enhance the memory protection unit security for applications. They have standard and advanced communication interfaces, and are built-in with 1MB of Flash memory, with a data bus width of 32bit. They have three low-power modes (sleep mode, stop mode, standby mode), and can be started in a short time. The STM32F412CGU6 and STM32L4Q5CGU6 minimum systems of STMicroelectronics have the same and small enough package sizes, and are both suitable for downhole environments.

[0059] In some embodiments, the MCU module 100 is cooperated with a 10KΩ surface mount resistor of the model RC0201FR-0710RL. The 10KΩ pull-up resistor plays a current limiting role, which can greatly reduce the current value flowing into the minimum system 101, prevent the minimum system 101 from being burned out, and can force the signal line to be clamped to a certain level to prevent the signal line from being in an uncertain state due to being floating.

[0060] According to the embodiments of the present invention, for the high-speed crystal oscillator 102 and the low-speed crystal oscillator 103, as clock sources, the MCU module 100 times time and marks data through the high-speed crystal oscillator 102 and the low-speed crystal oscillator 103.

[0061] The high-speed crystal oscillator 102 uses a passive crystal oscillator with a frequency of 8MHz, and the low-speed crystal oscillator 103 uses a passive crystal oscillator with a frequency of 32.768kHz. The high-speed crystal oscillator 102 and the low-speed crystal oscillator 103 are respectively equipped with frequencies, and the working power supply is powered by the battery module 10.

[0062] The high-speed crystal oscillator 102 and the low-speed crystal oscillator 103 respectively use crystal oscillator load capacitors of 10pF and 20pF to better ensure the stability of the external crystal oscillator output oscillation frequency of the minimum system 101.

[0063] In one embodiment, in order to save the electric energy of the battery module 10, a miniaturized downhole temperature and pressure measuring device with ultra-high temperature and ultra-high pressure resistance according to the present invention will be in a dormant state with extremely low power consumption for a long time before use, and will only be activated when actual data collection starts, so as to achieve the purpose of extending the measurement time.

[0064] Pressure measurement module

[0065] According to an embodiment of the present invention, the pressure measurement module includes a high-precision pressure sensor circuit 300, a high-precision ADC circuit 200, and a low-precision pressure sensor circuit 400.

[0066] The high-precision pressure sensor circuit 300 includes a first Wheatstone bridge 301 and a first operational amplifier 302. The low-precision pressure sensor circuit 400 includes a second Wheatstone bridge 401 and a second operational amplifier 402. The first Wheatstone bridge 301 and the second Wheatstone bridge 401 are connected to the porous conductive PDMS pressure sensing module 4 provided on the outer surface of the bullet-shaped package housing 1.

[0067] The amplification factor of the first operational amplifier 302 of the high-precision pressure sensor circuit 300 is 200 times. The high-precision pressure sensor circuit 300 performs analog-to-digital conversion through the high-precision ADC circuit 200 and communicates with the MCU module 100.

[0068] Specifically, the input end of the first operational amplifier 302 is connected to the first Wheatstone bridge 301, the output end of the first operational amplifier 302 is connected to the high-precision ADC circuit 200, and the high-precision ADC circuit 200 communicates with the minimum system 101 of the MCU module 100 in the I2C communication mode.

[0069] According to an embodiment of the present invention, the high-precision ADC circuit 200 selects an ADC circuit of the MCP3421 signal from Microchip of the United States.

[0070] The high-precision ADC circuit 200 converts the analog signal collected by the high-precision pressure sensor circuit 300 into a digital signal for the minimum system 101 of the MCU module 100 to read.

[0071] Any analog signal will be lost after analog-to-digital conversion. The number of ADC bits represents its resolution and directly determines the accuracy of analog-to-digital conversion. The MCP3421 selected for the high-precision ADC circuit 200 of the present invention is an 18-bit ADC with a resolution as high as 1 / 2 18 , while the ADC circuit built in the minimum system 101 is 12-bit with a resolution of only 1 / 2 12 .

[0072] Therefore, the high-precision ADC circuit 200 of the present invention can fully meet the high-precision requirements. The high-precision ADC circuit 200 of the present invention receives input from the first operational amplifier 302 with an amplification factor of 200 times, exchanges data with the minimum system 101 in the I2C communication mode, has an operating temperature of -40°C to 125°C, a small package size, and low power consumption.

[0073] In one embodiment, the driver of the high-precision ADC circuit 200 is directly downloaded to the MCU module 100 after being completed on a computer. The MCU module 100 sends working instructions to the high-precision ADC circuit 200 or receives the data transmitted back by it in the I2C communication mode.

[0074] According to an embodiment of the present invention, the amplification factor of the second operational amplifier 402 of the low-precision pressure sensor circuit 400 is 100 times. The low-precision pressure sensor circuit 400 communicates with the MCU module 100 through the ADC circuit built in the MCU module 100.

[0075] Specifically, the input end of the second operational amplifier 402 is connected to the second Wheatstone bridge 401, and the output end of the second operational amplifier 402 is connected to the ADC circuit built in the MCU module 100. Through the ADC circuit built in the MCU module 100, it communicates with the minimum system 101 of the MCU module 100.

[0076] The first Wheatstone bridge 301 and the second Wheatstone bridge 401 in the present invention are classic bridge circuits, which measure the change of physical quantity through the change of resistance value. The first Wheatstone bridge 301 and the second Wheatstone bridge 401 are connected to the porous conductive PDMS pressure sensing module 4 arranged on the outer surface of the bullet-shaped package housing 1. The porous conductive PDMS pressure sensing module 4 converts the external pressure change into a voltage change and transmits the voltage to the first operational amplifier 302 and the second operational amplifier 402 for amplification.

[0077] The voltage amplified by the first operational amplifier 302 is subjected to analog-to-digital conversion through the high-precision ADC circuit 200 and communicates with the minimum system 101 of the MCU module 100. The voltage amplified by the second operational amplifier 402 is subjected to analog-to-digital conversion through the ADC circuit built in the MCU module 100 and communicates with the minimum system 101 of the MCU module 100. By programming the MCU module 100, the external environmental pressure is deduced from the obtained voltage data.

[0078] The first operational amplifier 302 and the second operational amplifier 402 of the present invention select the AD8226ARMZ operational amplifier of Analog Devices. The AD8226ARMZ operational amplifier is a low-cost, wide power supply voltage range instrumentation amplifier, which only requires one external resistor to set the gain, and the gain range is from 1 to 1000.

[0079] The amplification factor of the first operational amplifier 302 is 200 times, which is used for high-precision and small-range pressure measurement. The amplification factor of the second operational amplifier 402 is 100 times, which is used for low-precision and large-range pressure measurement.

[0080] The first operational amplifier 302 and the second operational amplifier 402 are the AD8226ARMZ operational amplifiers from Analog Devices. The bandwidth (G = 1) is 1.5 MHz. The common-mode rejection ratio (G = 1) is at least 90 dB. The operating rated temperature is from -40°C to +125°C, and it uses a smaller MSOP package (mini small outline package), which is very suitable for highly compact and airtight underground environments.

[0081] According to an embodiment of the present invention, the first operational amplifier 302 and the second operational amplifier 402 are configured with PMOS transistors (P-channel depletion-mode field-effect transistors). Specifically, the first operational amplifier 302 is configured with a first PMOS transistor 303, and the second operational amplifier 402 is configured with a second PMOS transistor 403.

[0082] The first PMOS transistor 303 and the second PMOS transistor 403 are the PMOS transistors SI3139KL3-TP from Micro Commercial Components. The gate of the first PMOS transistor 303 is connected to the GPIO (General-purpose input / output) output port of the MCU module 100, the source is connected to the 3.3V network, and the drain is connected to the power supply port of the first operational amplifier 302.

[0083] The gate of the second PMOS transistor 403 is connected to the GPIO output port of the MCU module 100, the source is connected to the 3.3V network, and the drain is connected to the power supply port of the second operational amplifier 402.

[0084] By programming the MCU module 100 to control the open-drain of the first PMOS transistor 303 and the second PMOS transistor 403, and then controlling whether the first operational amplifier 302 and the second operational amplifier 402 work, the purpose of reducing power consumption and saving battery power is achieved.

[0085] Temperature measurement module

[0086] According to an embodiment of the present invention, the temperature measurement module includes a temperature sensor circuit 600. The temperature sensor circuit 600 includes a third operational amplifier 601, and the third operational amplifier 601 is connected to the cold end 9 of the thermocouple 3.

[0087] The amplification factor of the third operational amplifier 601 in the temperature sensor circuit 600 is 200 times. The temperature sensor circuit 600 communicates with the MCU module 100 through the ADC circuit built in the MCU module 100.

[0088] Specifically, the input terminal of the third operational amplifier 601 is connected to the cold end 9 of the thermocouple 3, and the output terminal of the third operational amplifier 601 is connected to the ADC circuit built in the MCU module 100. Through the ADC circuit built in the MCU module 100, it communicates with the minimum system 101 of the MCU module 100.

[0089] The hot end 8 of the thermocouple 3 extends to the external environment. The input end of the third operational amplifier 601 is connected to the cold end 9 of the thermocouple 3, and the output end of the third operational amplifier 601 is connected to the built-in 12-bit ADC circuit of the MCU module 100. The thermocouple 3 senses the change in the external temperature and converts it into a voltage change. The cold end 9 of the thermocouple 3 transmits the voltage to the third operational amplifier 601 for amplification. The amplified voltage of the third operational amplifier 601 is subjected to analog-to-digital conversion through the built-in 12-bit ADC circuit of the MCU module 100 and communicates with the minimum system 101 of the MCU module 100. By programming the MCU module 100, the external environmental temperature is deduced from the obtained voltage data.

[0090] In the present invention, since the temperatures of the cold end 9 and the hot end 8 of the thermocouple 3 are not interconnected, the high temperature received by the hot end 8 will not be transmitted along the thermocouple 3 to the control circuit board 5, thereby avoiding causing a failure of the control circuit board 5.

[0091] The third operational amplifier 601 of the present invention also selects the AD8226ARMZ operational amplifier of Analog Devices. Its performance has been described in the first operational amplifier 302 and the second operational amplifier 402 above, and will not be elaborated here.

[0092] Similarly, according to an embodiment of the present invention, the third operational amplifier 601 is configured with a PMOS transistor (P-channel depletion-mode field-effect transistor). Specifically, the third operational amplifier 601 is configured with a third PMOS transistor 602.

[0093] The third PMOS transistor 602 selects the PMOS transistor SI3139KL3-TP of Micro Commercial Components. The gate of the third PMOS transistor 602 is connected to the GPIO output port of the MCU module 100, the source is connected to the 3.3V network, and the drain is connected to the power supply port of the third operational amplifier 601.

[0094] By programming the MCU module 100 to control the open-drain of the third PMOS transistor 602, and further controlling whether the third operational amplifier 601 works, the purpose of reducing power consumption and saving battery power is achieved.

[0095] Power supply module

[0096] According to an embodiment of the present invention, the power supply module includes a power supply circuit 500, a battery interface 800, and a power supply filtering circuit 1000.

[0097] The power supply circuit 500 is used to generate a fixed regulated output voltage of 3.3V within a wide input voltage range (1.8V to 5.5V). The battery interface 800 is connected to the battery module 10. The power supply filtering circuit 1000 is configured with a chip capacitor to filter out high and low frequency noises in the power supply circuit 500.

[0098] In a specific embodiment, the power supply circuit 500 selects the LTC3240 of Analog Devices. When the input voltage is greater than the regulated output voltage, the power supply circuit 500 operates as a low-dropout regulator. Once the input voltage drops within 100 mV of the regulated output voltage, the power supply circuit 500 automatically switches to the boost mode. In the boost mode, the power supply circuit 500 operates as a constant-frequency (1.2 MHz) dual charge pump.

[0099] The power supply circuit 500 incorporates a soft-start circuit to prevent excessive inrush current during startup, and the thermal shutdown and current-limiting circuits allow the component to survive a continuous short circuit from VOUT (power output) to GND (ground terminal).

[0100] The power filter circuit 1000 of the present invention is configured with surface mount capacitors, which not only smooths and stabilizes the DC output of the battery module 10, reduces the impact of alternating pulsating current on the power supply circuit 500, but also absorbs the current fluctuations generated during the operation of the power supply circuit 500 and the interference coupled in via the AC power supply, making the operating performance of the power supply circuit 500 more stable.

[0101] The power filter circuit 1000 uses a 10 uF surface mount capacitor of model GRM155R61A106ME44D and a 100 nF surface mount capacitor of model GRM155R71C104KA88D. The large 10 uF capacitor can filter out the low-frequency noise in the power supply circuit 500, and the small 100 nF capacitor can filter out the high-frequency noise in the power supply circuit 500. The surface mount capacitors can play a decoupling role, meet the changes in the current driving the power supply circuit 500, and avoid mutual coupling interference.

[0102] Communication interface

[0103] According to an embodiment of the present invention, the control circuit board 5 integrates an SWD interface 700 and a serial communication interface 900, and the SWD interface 700 and the serial communication interface 900 are connected to the data interface 7.

[0104] The SWD interface 700 is a debugging interface reserved for the emulator, used for simulating and debugging the embedded program inside the MCU module 100. It requires fewer pins and relatively less space on the control circuit board 5, making it suitable for the micro temperature and pressure measurer.

[0105] For the serial communication interface 900, the MCU module 100 transmits the recorded or stored pressure and temperature data, tagged with time stamps, to the host computer through the serial communication interface 900, or receives instructions from the host computer. The communication method uses the serial communication method and commonly used hardware communication networks such as RS485 / RS422 / RS232.

[0106] In some embodiments, the MCU module 100 is configured with a Bluetooth communication interface to achieve wireless transmission of data.

[0107] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A miniaturized downhole temperature and pressure measuring device resistant to ultra-high temperature and ultra-high pressure, characterized in that, The temperature and pressure measuring device includes: a bullet-shaped encapsulation housing, which is formed by casting liquid polydimethylsiloxane and includes a bullet-shaped end face; A polytetrafluoroethylene aerogel layer and a control circuit board are arranged inside the bullet-shaped encapsulation housing, and the polytetrafluoroethylene aerogel layer wraps the control circuit board; A porous conductive PDMS pressure sensing module is arranged on the outer surface of the bullet-shaped encapsulation housing, and the porous conductive PDMS pressure sensing module is connected to the control circuit board; The temperature and pressure measuring device further includes a thermocouple. The cold end of the thermocouple is connected to the control circuit board, and the hot end of the thermocouple extends to and protrudes from the bullet-shaped end face; An MCU module, a pressure measurement module, a temperature measurement module, and a power supply module are integrated on the control circuit board, and the MCU module includes a minimum system; Among them, the pressure measurement module includes a high-precision pressure sensor circuit, a high-precision ADC circuit, and a low-precision pressure sensor circuit. The high-precision pressure sensor circuit includes a first Wheatstone bridge and a first operational amplifier. The low-precision pressure sensor circuit includes a second Wheatstone bridge and a second operational amplifier. The first Wheatstone bridge and the second Wheatstone bridge are connected to the porous conductive PDMS pressure sensing module arranged on the outer surface of the bullet-shaped encapsulation housing; Among them, the high-precision pressure sensor circuit performs analog-to-digital conversion through the high-precision ADC circuit and communicates with the MCU module; The low-precision pressure sensor circuit communicates with the MCU module through the ADC circuit built in the MCU module; The temperature measurement module includes a temperature sensor circuit, and the temperature sensor circuit includes a third operational amplifier. The third operational amplifier is connected to the cold end of the thermocouple; The input end of the first operational amplifier is connected to the first Wheatstone bridge, and the output end of the first operational amplifier is connected to the high-precision ADC circuit. The high-precision ADC circuit communicates with the MCU module in an I2C communication manner.

2. The temperature and pressure measuring device according to claim 1, characterized in that, The temperature and pressure measuring device further includes a battery module, and the polytetrafluoroethylene aerogel layer wraps the battery module.

3. The temperature and pressure measuring device according to claim 1, characterized in that, The control circuit board is parallel to the end face of the hot end of the thermocouple.

4. The temperature and pressure measuring device according to claim 1, characterized in that, The input end of the second operational amplifier is connected to the second Wheatstone bridge, and the output end of the second operational amplifier is connected to the ADC circuit built in the MCU module.

5. The temperature and pressure measuring device according to claim 1, characterized in that The input end of the third operational amplifier is connected to the cold end of the thermocouple, and the output end of the third operational amplifier is connected to the ADC circuit built in the MCU module.

6. The temperature and pressure measuring device according to claim 4 or 5, characterized in that , The MCU module further includes a high-speed crystal oscillator and a low-speed crystal oscillator.

7. The pyrobarometer according to claim 1, wherein , The power supply module includes a power supply circuit, a battery interface, and a power supply filter circuit; The power supply circuit is used to generate a fixed regulated output voltage of 3.3V within a wide input voltage range, and the battery interface is connected to the battery module; The power supply filter circuit is configured with chip capacitors to filter out high-frequency and low-frequency noises in the power supply circuit.

8. The temperature and pressure measuring device according to claim 1, characterized in that , An SWD interface and a serial communication interface are also integrated on the control circuit board.

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