Capacitive sensor and logging instrument

Abstract

The invention relates to a capacitive sensor and a logging instrument.The capacitive sensor comprises a sensor body, a connecting structure is arranged on the sensor body and used for connecting the sensor body to the lower end of an acquisition short section, and the lower end of the sensor body can make contact with fluid; a sealing structure is arranged between the sensor body and the collection short section; the upper end of the sensor body is provided with a circuit module, the circuit module is used for generating sine waves, the upper end of the sensor body is connected with a positive pole in an insulating manner, the sensor body is conductively connected with a negative pole, the positive pole and the negative pole are both connected with the circuit module, and the circuit module is used for being connected with an acquisition nipple. The sensor body is connected with the acquisition short section, so that the defect that a plurality of capacitors are connected to the acquisition short section in a long distance through a cable after being connected in parallel is overcome; and the circuit module is arranged on the sensor body, so that the purpose of sending sine waves into the collection short section is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sensors, and in particular relates to a capacitive sensor and a well logging instrument. Background Art

[0002] At present, some high-temperature sensors of downhole logging instruments are placed on a mechanical device with multiple small parallel capacitance sensors, which are connected to the acquisition circuit through long cables. Since the capacitance sensor is easily affected by the long cable when outputting its capacitance value, when the capacitance value changes, the acquisition circuit will make errors in judging the downhole fluid. Summary of the invention

[0003] In order to solve all or part of the above problems, the present invention aims to provide a capacitive sensor and a logging instrument, wherein the sensor body is connected to the acquisition short section, and a circuit module for generating a sine wave is provided on the sensor body, thereby achieving the purpose of sending the sine wave to the acquisition short section.

[0004] According to one aspect of the present invention, there is provided a capacitive sensor, comprising a sensor body, wherein a connection structure is provided on the sensor body, wherein the connection structure is used to connect the sensor body to the lower end of a collection nipple, wherein the lower end of the sensor body can be in contact with a fluid, and a sealing structure is provided between the sensor body and the collection nipple;

[0005] A circuit module is provided at the upper end of the sensor body, and the circuit module is used to generate a sine wave. The upper end of the sensor body is insulated and connected with a positive pole, and the sensor body is conductively connected with a negative pole. Both the positive pole and the negative pole are connected to the circuit module, and the circuit module is used to be connected to the collection short section.

[0006] Furthermore, the connecting structure is arranged at the lower end of the sensor body, the sensor body is connected to the lower end of the collection short section through the connecting structure, the upper end of the sensor body extends into the collection short section, and the sealing structure is arranged between the sensor body and the collection short section.

[0007] Furthermore, the lower end of the sensor body is insulated and sealed with a positive electrode plate, and the side of the positive electrode plate in contact with the fluid is coated with an insulating layer; the positive electrode plate is connected to the positive electrode post through a connecting wire, and the connecting wire and the sensor body are arranged to be insulated from each other; the sensor body is made of titanium alloy, and the positive electrode plate and the positive electrode post are both made of copper.

[0008] Furthermore, the connection structure includes a plurality of mounting guard arms fixed to the lower end of the sensor body, each of the mounting guard arms is provided with a threaded hole, and the connection structure is connected to the lower end of the acquisition short section by threaded fasteners passing through corresponding threaded holes.

[0009] Furthermore, a plurality of sealing grooves are arranged on the outer side wall of the sensor body, and the sealing structure is a sealing ring arranged in the sealing groove.

[0010] Furthermore, a mounting groove extending downward is formed at the upper end of the sensor body, and the circuit module is fixed in the mounting groove by solidifying glue.

[0011] Further, the circuit module includes a CAP+ pin, a GND pin, a SINOUT pin and a +5V power supply, the positive pole is connected to the CAP+ pin, the negative pole is connected to the GND pin, and the circuit module is connected to the collection short section through the SINOUT pin;

[0012] The CAP+ pin is connected to one end of the second resistor, one end of the ninth resistor, one end of the first capacitor and one end of the second capacitor, and the other end of the first capacitor and the other end of the second capacitor are both connected to the GND pin;

[0013] The other end of the ninth resistor is connected to one end of the fifth resistor, one end of the first resistor and the output end of the first operational amplifier; the inverting input pin of the first operational amplifier is connected to the other end of the second resistor, the other end of the first resistor is connected to a 2.5V power supply, the 2.5V power supply is connected to the non-inverting input pin of the first operational amplifier through a fourth resistor, and the 2.5V power supply is obtained from the +5V power supply;

[0014] The other end of the fifth resistor is connected to the non-inverting input pin of the second operational amplifier, the inverting input pin of the second operational amplifier is connected to the output end of the second operational amplifier, the output end of the second operational amplifier is connected to the SINOUT pin, and a sixth resistor is connected between the SINOUT pin and the GND pin;

[0015] The positive power pin of the first operational amplifier and the positive power pin of the second operational amplifier are both connected to the +5V power supply, and the negative power pin of the first operational amplifier and the negative power pin of the second operational amplifier are both connected to the GND pin.

[0016] Further, the +5V power supply is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the GND pin, the resistance values ​​of the seventh resistor and the eighth resistor are equal, so that the voltage of the second end of the seventh resistor is 2.5V, and the second end of the seventh resistor is connected to the other end of the resistor.

[0017] Further, the circuit module includes an upper part and a lower part, the first operational amplifier and the second operational amplifier are both arranged in the upper part, and the second resistor, the ninth resistor, the first capacitor, the second capacitor, the fifth resistor, the first resistor, the fourth resistor and the sixth resistor are all arranged in the lower part; the upper part and the lower part are both provided with a SINOUT interface, a +5V power supply interface, a GND interface and a CAP+ interface, wherein the CAP+ interface is used for a wire connected to the CAP+ pin to pass through, the SINOUT interface is used for a wire connected to the SINOUT pin to pass through, the +5V power supply interface is used for a wire connected to the +5V power supply to pass through, and the GND interface is used for a wire connected to the GND pin to pass through;

[0018] The circuit module is 19 mm long and 8 mm wide.

[0019] According to another aspect of the present invention, a well logging instrument is provided, comprising any one of the capacitive sensors described above.

[0020] It can be seen from the above technical solution that the capacitive sensor and well logging instrument provided by the present invention have the following beneficial effects:

[0021] The sensor body of the present invention is connected to the collection short section, thereby overcoming the disadvantage of connecting multiple capacitors in parallel to the collection short section through cables over a long distance; and a circuit module for generating a sine wave is provided on the sensor body, thereby achieving the purpose of sending the sine wave to the collection short section. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a capacitive sensor according to an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of a capacitive sensor according to an embodiment of the present invention;

[0024] Figure 3 This is the circuit schematic diagram of the circuit module. DETAILED DESCRIPTION

[0025] In order to better understand the purpose, structure and function of the present invention, a capacitive sensor and a well logging instrument of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0026] like Figure 1-Figure 2 As shown, it shows a capacitive sensor according to an embodiment of the present invention, including a sensor body 8, on which a connection structure is provided, the connection structure is used to connect the sensor body 8 to the lower end of the collection short section, the lower end of the sensor body 8 can be in contact with the fluid, and a sealing structure is provided between the sensor body 8 and the collection short section; a circuit module is provided at the upper end of the sensor body 8, the circuit module is used to generate a sine wave, the upper end of the sensor body 8 is insulated and connected with a positive pole 6, the sensor body 8 is conductively connected with a negative pole 4, both the positive pole 6 and the negative pole 4 are connected to the circuit module, and the circuit module is used to connect to the collection short section.

[0027] Specifically, the capacitive sensor of this embodiment includes a mechanical part and a circuit part, wherein the mechanical part is the sensor body 8, and a connecting structure is provided on the sensor body 8, and the sensor body 8 is connected to the lower end of the collection short section through the connecting structure; secondly, the sensor body 8 and the collection short section are sealed and connected, and the circuit module is arranged at the upper end of the sensor body 8, so the circuit module will not contact the fluid at the lower end of the sensor body 8, thereby avoiding the influence of the fluid on the circuit module.

[0028] Again, in this embodiment, the upper end of the sensor body 8 is insulated and connected with the positive pole 6, and the sensor body 8 is conductively connected with the negative pole 4, and the positive pole 6 and the negative pole 4 form two pole pieces of the capacitor. The positive pole 6 is arranged at the upper end of the sensor body 8, so the positive pole 6 cannot contact the fluid; because the lower end of the sensor body 8 can contact the fluid, the negative pole 4 can contact the fluid.

[0029] The circuit module of this embodiment is used to generate a sine wave, and the circuit module is used to connect to the collection short section, so in this embodiment, the sine wave generated by the circuit module is directly sent to the collection short section. Therefore, compared with the prior art, the capacitor formed by the positive pole 6 and the negative pole 4 of this embodiment does not need to be connected to the collection short section through a long cable, thereby overcoming the problem in the prior art that the capacitance value changes due to the circuit of the collection short section being connected to multiple capacitors in parallel through a long cable.

[0030] To further illustrate, since different liquids have different dielectric constants, when the lower end of the sensor body 8 of this embodiment is in different media, corresponding sine waves of different frequencies will be generated in the circuit module. Therefore, the capacitive sensor of this embodiment can be used to identify three liquid media: oil, gas and water underground.

[0031] In a specific embodiment, the connection structure is disposed at the lower end of the sensor body 8, the sensor body 8 is connected to the lower end of the collection short section through the connection structure, the upper end of the sensor body 8 extends into the collection short section, and the sealing structure is disposed between the sensor body 8 and the collection short section.

[0032] Specifically, in this embodiment, the connection structure is arranged at the lower end of the sensor body 8, the sensor body 8 is connected to the lower end of the collection short section through the connection structure at the lower end thereof, and the upper end of the sensor body 8 extends upward to extend into the collection short section. Secondly, the sealing structure is arranged between the middle part of the sensor body 8 and the collection short section.

[0033] Again, regarding the positive pole 6 and the negative pole 4 that form the capacitor, the positive pole 6 is located above the sealing structure, so the positive pole 6 will not contact the fluid; when the lower end of the sensor body 8 is located in the fluid, the sensor body 8 is conductively connected to the negative pole 4, so the negative pole 4 can contact the fluid. The circuit module is arranged at the upper end of the sensor body 8, that is, above the sealing structure, so the circuit module will not contact the fluid.

[0034] In a specific embodiment, the lower end of the sensor body 8 is insulated and sealed with a positive electrode plate 5, and the side of the positive electrode plate 5 in contact with the fluid is coated with an insulating layer; the positive electrode plate 5 is connected to the positive electrode column 6 through a connecting wire, and the connecting wire and the sensor body 8 are arranged to be insulated from each other; the sensor body 8 is made of titanium alloy, and the positive electrode plate 5 and the positive electrode column 6 are both made of copper.

[0035] Specifically, the positive electrode piece 5 and the sensor are sealed and insulated from each other. Since the positive electrode piece 5 is located at the lower end of the sensor body 8, an insulating layer is applied to the side of the positive electrode piece 5 in contact with the fluid in this embodiment. The positive electrode piece 5 is connected to the positive electrode post 6 located at the upper end of the sensor body 8 through a wire, and the positive electrode piece 5, the positive electrode post 6 and the connecting wire are all insulated from the sensor body 8.

[0036] Thirdly, in specific implementation, the positive electrode column 6 and the positive electrode plate 5 can both be made of copper with good electrical conductivity; the sensor body 8 is made of titanium alloy resistant to high temperature and high pressure.

[0037] In a specific embodiment, the connection structure includes a plurality of mounting arms 2 fixed to the lower end of the sensor body 8, each mounting arm 2 is provided with a threaded hole 1, and the connection structure is connected to the lower end of the acquisition short section through a threaded fastener passing through the corresponding threaded hole 1. Specifically, the sensor body 8 and the acquisition short section are connected by a threaded fastener. As an alternative, the sensor body 8 and the acquisition short section can also be connected by other structures, such as by matching external and internal threads, by connecting pins, etc.

[0038] In a specific embodiment, a plurality of sealing grooves 3 are provided on the outer side wall of the sensor body 8, and the sealing structure is a sealing ring provided in the sealing groove 3. In this embodiment, the sealing between the sensor body 8 and the acquisition nipple is achieved by the cooperation between the sealing groove 3 and the sealing ring. Specifically, the sealing groove 3 is provided on the outer circumference of the sensor body 8, and the sealing structure is a sealing ring provided in the sealing groove 3.

[0039] In a specific embodiment, a downwardly extending mounting groove 7 is formed at the upper end of the sensor body 8 , and the circuit module is fixed in the mounting groove 7 by solidifying glue.

[0040] In a specific embodiment, if Figure 3 As shown, the circuit module includes a CAP+ pin, a GND pin, a SINOUT pin and a +5V power supply. Among them, the positive pole 6 is connected to the CAP+ pin, and the negative pole 4 is connected to the GND pin, so that the positive pole 6 and the negative pole 4 forming the capacitor are connected to the circuit module; the circuit module is connected to the collection short section through the SINOUT pin, so that the sine wave is sent to the collection short section through the SINOUT pin.

[0041] The CAP+ pin is connected to one end of the second resistor R2, one end of the ninth resistor R9, one end of the first capacitor C1 and one end of the second capacitor C2, and the other end of the first capacitor C1 and the other end of the second capacitor C2 are both connected to the GND pin; the other end of the ninth resistor R9 is connected to one end of the fifth resistor R5, one end of the first resistor R1 and the output end of the first operational amplifier U1; the inverting input pin of the first operational amplifier U1 is connected to the other end of the second resistor R2, the other end of the first resistor R1 is connected to a 2.5V power supply, the 2.5V power supply is connected to the non-inverting input pin of the first operational amplifier U1 through the fourth resistor R4, and the 2.5V power supply is obtained from the +5V power supply; the other end of the fifth resistor R5 is connected to the non-inverting input pin of the second operational amplifier U2, the inverting input pin of the second operational amplifier U2 is connected to the output end of the second operational amplifier U2, the output end of the second operational amplifier U2 is connected to the SINOUT pin, and a sixth resistor R6 is connected between the SINOUT pin and the GND pin.

[0042] Specifically, the circuit module of this embodiment is connected to the positive electrode 6 through the CAP+ pin, and is connected to the negative electrode 4 through the GND pin. When the sensor body 8 comes into contact with the fluid, due to the different dielectric constants of different fluids, sinusoidal waves of different frequencies are generated through the first operational amplifier U1, the second operational amplifier U2, the second resistor R2, the ninth resistor R9, the first capacitor C1, the second capacitor C2, the fifth resistor R5, the first resistor R1, the fourth resistor R4 and the sixth resistor R6, and are sent to the acquisition short section through the SINOUT pin.

[0043] In specific settings, the first capacitor C1 is 150pF, the second capacitor C2 is 120pF, the first resistor R1 is 1K, the resistance values ​​of the second resistor R2, the ninth resistor R9, and the fourth resistor R4 are all 10K, and the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 can be adjusted as needed.

[0044] Again, the first operational amplifier U1 and the second operational amplifier U2 are both active devices. In this embodiment, the positive power pin of the first operational amplifier U1 and the positive power pin of the second operational amplifier U2 are both connected to the +5V power supply, and the negative power pin of the first operational amplifier U1 and the negative power pin of the second operational amplifier U2 are both connected to the GND pin.

[0045] In a specific embodiment, a +5V power supply is connected to the first end of the seventh resistor R7, the second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the GND pin, the resistance values ​​of the seventh resistor R7 and the eighth resistor R8 are equal, so that the voltage of the second end of the seventh resistor R7 is 2.5V, and the second end of the seventh resistor R7 is connected to the other end of the resistor R1.

[0046] Specifically, in this embodiment, the seventh resistor R7 and the eighth resistor R8 are connected in series through series voltage division and then connected between the +5V power supply and the GND pin, and when the resistance values ​​of the seventh resistor R7 and the eighth resistor R8 are equal, a voltage of 2.5V is obtained. In specific implementation, for example, the resistance values ​​of the seventh resistor R7 and the eighth resistor R8 are both 1K.

[0047] In a specific embodiment, the circuit module includes an upper part and a lower part, the first operational amplifier U1 and the second operational amplifier U2 are both arranged in the upper part, and the second resistor, the ninth resistor R9, the first capacitor C1, the second capacitor C2, the fifth resistor R5, the first resistor R1, the fourth resistor R4 and the sixth resistor R6 are all arranged in the lower part; the upper part and the lower part are both provided with interfaces for wires to pass through.

[0048] In this embodiment, the circuit module is divided into an upper layer and a lower layer, thereby reducing the volume of the sensor body 8. The components between the upper and lower layers are connected through wires passing through corresponding interfaces. In specific implementation, for example, both the upper layer and the lower layer are provided with a SINOUT interface, a +5V power interface, a GND interface, and a CAP+ interface.

[0049] In a specific implementation, by setting the circuit module as a double-layer structure, the length and / or width of the circuit module can be reduced by reasonably distributing the components in the upper and lower layers. The circuit module of this embodiment is 19 mm long and 8 mm wide.

[0050] In the specific implementation again, high temperature components that can withstand high temperatures above 175 degrees can be selected, so that the capacitive sensor of this embodiment can be used in a high temperature environment above 175 degrees; the capacitive sensor of the embodiment of the present invention is small in size, which reduces the internal space occupied by the logging instrument. The capacitive sensor of the embodiment of the present invention can test the insulation of the hydraulic oil of the instrument by adjusting the capacitance and resistance parameters in the RC oscillation circuit. The capacitive sensor of the embodiment of the present invention has a simple structure, high reliability and low production cost.

[0051] Again, an embodiment of the present invention further provides a well logging instrument, which includes the capacitive sensor of any one of the above embodiments.

[0052] Therefore, compared with the prior art, the capacitor formed by the positive pole 6 and the negative pole 4 in this embodiment does not need to be connected to the collection short section through a long cable, thereby overcoming the problem in the prior art that the capacitance value changes due to the connection of multiple capacitors in parallel to the circuit of the collection short section through a long cable. In addition, a circuit module for generating a sine wave is provided on the sensor body 8, thereby achieving the purpose of sending the sine wave to the collection short section.

[0053] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the invention belongs.

[0054] In addition, the terms "one", "two", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0055] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; 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, and they should all be included in the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A capacitive sensor, characterized in that: The sensor body comprises a connecting structure, wherein the connecting structure is used to connect the sensor body to the lower end of the acquisition short section, the lower end of the sensor body can be in contact with the fluid, and a sealing structure is provided between the sensor body and the acquisition short section; A circuit module is provided at the upper end of the sensor body, and the circuit module is used to generate a sine wave. The upper end of the sensor body is insulated and connected with a positive pole, and the sensor body is conductively connected with a negative pole. Both the positive pole and the negative pole are connected to the circuit module, and the circuit module is used to be connected to the collection short section.

2. The capacitive sensor according to claim 1, characterized in that: The connecting structure is arranged at the lower end of the sensor body, the sensor body is connected to the lower end of the collection short section through the connecting structure, the upper end of the sensor body extends into the collection short section, and the sealing structure is arranged between the sensor body and the collection short section.

3. The capacitive sensor according to claim 2, characterized in that: The lower end of the sensor body is insulated and sealed with a positive electrode plate, and the side of the positive electrode plate in contact with the fluid is coated with an insulating layer; the positive electrode plate is connected to the positive electrode post through a connecting wire, and the connecting wire and the sensor body are arranged to be insulated from each other; the sensor body is made of titanium alloy, and the positive electrode plate and the positive electrode post are both made of copper.

4. The capacitive sensor according to claim 2, characterized in that: The connection structure comprises a plurality of mounting guard arms fixed to the lower end of the sensor body, each of the mounting guard arms is provided with a threaded hole, and the connection structure is connected to the lower end of the acquisition short section by threaded fasteners passing through corresponding threaded holes.

5. The capacitive sensor according to claim 2, characterized in that: A plurality of sealing grooves are arranged on the outer side wall of the sensor body, and the sealing structure is a sealing ring arranged in the sealing groove.

6. The capacitive sensor according to claim 1, characterized in that: The upper end of the sensor body is provided with a mounting groove extending downward, and the circuit module is fixed in the mounting groove by solidifying glue.

7. The capacitive sensor according to claim 1, characterized in that: The circuit module includes a CAP+ pin, a GND pin, a SINOUT pin and a +5V power supply, the positive pole is connected to the CAP+ pin, the negative pole is connected to the GND pin, and the circuit module is connected to the collection short section through the SINOUT pin; The CAP+ pin is connected to one end of the second resistor, one end of the ninth resistor, one end of the first capacitor and one end of the second capacitor, and the other end of the first capacitor and the other end of the second capacitor are both connected to the GND pin; The other end of the ninth resistor is connected to one end of the fifth resistor, one end of the first resistor and the output end of the first operational amplifier; the inverting input pin of the first operational amplifier is connected to the other end of the second resistor, the other end of the first resistor is connected to a 2.5V power supply, the 2.5V power supply is connected to the non-inverting input pin of the first operational amplifier through a fourth resistor, and the 2.5V power supply is obtained from the +5V power supply; The other end of the fifth resistor is connected to the non-inverting input pin of the second operational amplifier, the inverting input pin of the second operational amplifier is connected to the output end of the second operational amplifier, the output end of the second operational amplifier is connected to the SINOUT pin, and a sixth resistor is connected between the SINOUT pin and the GND pin; The positive power pin of the first operational amplifier and the positive power pin of the second operational amplifier are both connected to the +5V power supply, and the negative power pin of the first operational amplifier and the negative power pin of the second operational amplifier are both connected to the GND pin.

8. The capacitive sensor according to claim 7, characterized in that: The +5V power supply is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the GND pin, the resistance values ​​of the seventh resistor and the eighth resistor are equal, so that the voltage of the second end of the seventh resistor is 2.5V, and the second end of the seventh resistor is connected to the other end of the resistor.

9. The capacitive sensor according to claim 7, characterized in that: The circuit module includes an upper part and a lower part, the first operational amplifier and the second operational amplifier are both arranged in the upper part, and the second resistor, the ninth resistor, the first capacitor, the second capacitor, the fifth resistor, the first resistor, the fourth resistor and the sixth resistor are all arranged in the lower part; the upper part and the lower part are both provided with a SINOUT interface, a +5V power interface, a GND interface and a CAP+ interface, wherein the CAP+ interface is used for a wire connected to the CAP+ pin to pass through, the SINOUT interface is used for a wire connected to the SINOUT pin to pass through, the +5V power interface is used for a wire connected to the +5V power supply to pass through, and the GND interface is used for a wire connected to the GND pin to pass through; The circuit module is 19 mm long and 8 mm wide.

10. A well logging instrument, characterized in that: A capacitive sensor comprising any one of claims 1-9.

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