Gas well sand production and erosion integrated monitoring system and monitoring method

Abstract

The invention discloses a gas well sand production and erosion integrated monitoring system and a monitoring method, by setting a sand production signal and the emission signal frequency of an erosion sensor, an ultrasonic signal emitted by the erosion sensor is prevented from influencing a sand production monitoring sensor, and by amplifying and filtering the sand production signal, the original sand production signal is reserved, so that the monitoring accuracy is improved. And the influence of an erosion emission signal is eliminated. By comparing the voltage of the sand production signal with the threshold voltage, pipeline vibration and fluid noise are eliminated, invalid signals are screened out, the storage space is saved, and more effective data can be stored. The transducers of the two erosion sensors are arranged on the same plane without an included angle, so that the adaptive wall thickness range is wider.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas field surface engineering monitoring, and particularly relates to an integrated monitoring system and method for sand production and erosion of gas wells. Background Technique

[0002] The main methods for sand production monitoring of gas wells include ultrasonic monitoring method and resistivity (ER, Electrical Resistance) monitoring method. The ER monitoring method uses an in-line sensor. After sand grains impact the metal probe of the sensor, metal defects are caused, thereby causing a change in the resistance of the metal probe. The sand production situation of the gas well is identified according to the change in resistance. The problem with this method is that it is necessary to open holes in the production pipeline to install the sensor, and the sensor needs to be replaced after being used for a period of time. Whether it is opening holes or replacing the sensor, it brings adverse factors to safety and the normal production of gas wells. Therefore, it is difficult to be accepted by oil fields. The ultrasonic detection uses an external sensor, does not require drilling holes in the pipeline, and is convenient to replace. It is the most common method at present, but the problem is that it cannot monitor the erosion effect of sand production on the pipe wall.

[0003] In order to monitor the erosion situation, the present invention combines with an erosion sensor while monitoring the sand production situation by the ultrasonic method, so as to realize the simultaneous monitoring of the sand production volume and the pipe wall thickness.

[0004] Erosion monitoring is used to measure the remaining thickness after the wall thickness is thinned due to sand grains impacting the pipe wall. The most commonly used method is to measure the wall thickness by the pulse method. The time experienced by the transmitted and received pulses and the speed of sound waves are used by the integrated transceiver sensor to obtain the wall thickness of the pipe. The problem is that there is a certain angle between the transmitting transducer and the receiving transducer in the sensor, and the measurable wall thickness range is limited. The present invention adopts a planar sensor structure without an angle between the transmitting and receiving transducers, and the measurement range is wider.

[0005] The prior art can either only monitor the sand production situation of gas wells or only monitor the erosion situation. The combined monitoring of the two has important significance for sand production and safe production. However, the sensitive part of sand production monitoring is also the most severely eroded part. Since erosion monitoring requires the emission of sound waves, the frequency range is very wide and covers the frequency range of sand production signals, which affects the sand production monitoring. Therefore, it is necessary to eliminate the influence of the emission signal during erosion monitoring on sand production monitoring. Summary of the Invention

[0006] The purpose of the present invention is to provide an integrated monitoring system and method for sand production and erosion of gas wells, realizing on-line monitoring and combination with sand production monitoring.

[0007] The purpose of the present invention is achieved by the following technical means. An integrated monitoring system for sand production and erosion of gas wells includes

[0008] The signal acquisition unit includes a sand production monitoring sensor for receiving ultrasonic signals caused by sand grains hitting the pipe wall, and two erosion sensors for transmitting pulse signals and receiving echo signals from the inner wall of the pipe, where one is used for transmitting signals and the other is used for receiving signals; the sensitive surfaces of the three sensors are located on the same plane.

[0009] The signal processing unit is used to amplify and filter the output signal of the sand production monitoring sensor, amplify, filter and shape the output signal of the erosion sensor for receiving signals, and amplify the signal for controlling the signal transmitted by the erosion sensor.

[0010] The data calculation unit includes a digital filtering module for filtering out the interference signals of the erosion sensor in the sand production signal; a sand production signal detection module for analyzing whether the output signal is valid after receiving the output signal of the sand production monitoring sensor; an erosion sensor control module for controlling an erosion sensor to emit ultrasonic waves and timing, and stopping timing when the other erosion sensor receives the ultrasonic waves to obtain a time difference; a sand production rate and pipe wall calculation module for calculating the sand production rate and the pipe wall thickness through the output voltage value of the sand production signal and the time difference detected by the erosion sensor.

[0011] There are multiple groups of the signal acquisition units, which are respectively connected to different gas well pipes.

[0012] It further includes a first multiplexing module and a second multiplexing module. Both the first multiplexing module and the second multiplexing module are electrically connected to the data calculation unit. The sand production monitoring sensor of each group of signal acquisition units is connected to the first multiplexing module, and the first multiplexing module is also electrically connected to the signal processing unit; the erosion sensor for transmitting signals of each group of signal acquisition units is electrically connected to the second multiplexing module, and the second multiplexing module is electrically connected to the signal processing unit.

[0013] The signal acquisition unit is installed on the outer wall of the elbow of the gas well pipe in the oncoming flow direction.

[0014] The frequency range of the output signal of the sand production monitoring sensor is 100 kHz - 500 kHz, and the signal transmitted by the erosion sensor is a sine wave above 1 MHz.

[0015] The signal acquisition unit further includes a housing, and the erosion sensor and the sand production monitoring sensor are installed inside the housing.

[0016] It further includes a sound insulation layer. The two erosion sensors are respectively connected to both sides of the sound insulation layer. The erosion sensor includes a damping block, a piezoelectric ceramic wafer and a delay block. The bottom of the delay block is parallel to the ground of the housing. The top of the delay block, the side in contact with the sound insulation layer is higher than the opposite side. The piezoelectric ceramic wafer is connected to the top of the delay block, and the damping block is connected to the delay block and wraps the piezoelectric ceramic wafer.

[0017] An integrated monitoring method for sand production and erosion in gas wells, comprising the following steps,

[0018] Monitoring by a sand production monitoring sensor. The sand production monitoring sensor monitors the ultrasonic waves caused by sand grains colliding with the pipe wall. After the sand production signal is output, amplified, filtered, and collected, it is transmitted to the data calculation unit. The data calculation unit monitors whether the sand production signal is valid. If it is valid, the data calculation unit controls the ultrasonic erosion monitoring sensor to start working. If it is invalid, it is considered that there is no sand and gravel erosion;

[0019] Monitoring by an erosion sensor. The data calculation unit controls an erosion sensor to emit an ultrasonic signal and start timing. After another erosion sensor receives the corresponding ultrasonic signal, it stops timing, and the time difference is returned to the data calculation unit to calculate the wall thickness and sand production rate.

[0020] Through the data calculation unit, control a certain path of the first multiplexing module to conduct, transmit the output signal of a sand production monitoring sensor to the data calculation unit, and control the erosion sensor in the same group as the sand production monitoring sensor of the second multiplexing module to communicate. This erosion sensor receives the control signal of the data calculation unit and emits ultrasonic waves.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. By setting the sand production signal and the emission signal frequency of the erosion sensor, the ultrasonic signal emitted by the erosion sensor is prevented from affecting the sand production monitoring sensor, and by amplifying and filtering the sand production signal, the original sand production signal is retained, and the influence of the erosion emission signal is eliminated.

[0023] 2. By comparing the voltage of the sand production signal with the threshold voltage, pipeline vibration and fluid noise are eliminated, invalid signals are screened out, saving storage space for storing more valid data.

[0024] 3. The transducers of the two erosion sensors are arranged on the same plane, and there is no included angle between them, adapting to a wider range of wall thicknesses. Brief Description of the Drawings

[0025] Figure 1 It is a flow chart of an integrated monitoring method for sand production and erosion in gas wells;

[0026] Figure 2 It is a schematic structural diagram of an integrated erosion sensor;

[0027] Figure 3 It is a schematic structural diagram of a signal acquisition unit;

[0028] Figure 4 It is a schematic installation diagram of a signal acquisition unit;

[0029] Figure 5 It is a schematic diagram of the principle of the pulse emission method;

[0030] Figure 6 are the ultrasonic emission waveform and the received waveform diagram;

[0031] Figure 7 is a structural diagram of an integrated monitoring system for sand production and erosion in a gas well;

[0032] Figure 8 is a design diagram of a FIR filter;

[0033] In the figure, 1 is the sand production monitoring sensor; 2 is the erosion sensor; 3 is the outer shell; 4 is the sound insulation layer; 5 is the damping block; 6 is the piezoelectric ceramic wafer; 7 is the delay block.

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Specific embodiments

[0035]

Embodiment 1

[0036] As Figure 7 shown, an integrated monitoring system for sand production and erosion in a gas well includes

[0037] a signal acquisition unit, including a sand production monitoring sensor 1 for receiving ultrasonic signals caused by sand grains hitting the pipe wall, and two erosion sensors 2 for transmitting pulse signals and receiving echo signals from the inner wall of the pipe, where one is used for transmitting signals and the other is used for receiving signals; the sensitive surfaces of the three sensors are located on the same plane;

[0038] a signal processing unit, which is used to amplify and filter the output signal of the sand production monitoring sensor 1, amplify, filter and shape the output signal of the erosion sensor 2 for the received signal, and amplify the signal for controlling the signal transmitted by the erosion sensor 2;

[0039] a data calculation unit, including a digital filtering module for screening out the interference signals of the erosion sensor 2 in the sand production signal; a sand production signal detection module for analyzing whether the output signal is valid after receiving the output signal of the sand production monitoring sensor 1; an erosion sensor control module for controlling an erosion sensor 2 to emit ultrasonic waves and timing, and stopping timing when the other erosion sensor 2 receives the ultrasonic waves to obtain a time difference; a sand production rate and pipe wall calculation module for calculating the sand production rate and the pipe wall thickness through the output voltage value of the sand production signal and the time difference detected by the erosion sensor 2.

[0040] The sand production monitoring sensor 1 is connected to the outer wall of the pipe and is used to monitor ultrasonic signals. The sand production monitoring sensor 1 is a passive monitoring. The monitored signals are not only the ultrasonic signals caused by sand grains hitting the pipe wall, but also may be non-effective signals such as pipe vibration, fluid noise, and signals transmitted by the erosion sensor 2.

[0041] Moreover, the sand production signal detected by the sand production monitoring sensor 1 is very weak, so a signal processing unit is needed to amplify the sand production signal.

[0042] The frequency range of the output signal of the sand production monitoring sensor 1 is 100 kHz - 500 kHz, and the signal emitted by the erosion sensor 2 is a sine wave above 1 MHz.

[0043] The sand production signal is physically filtered through the amplification and filtering circuit in the signal processing unit. After filtering, the sand production signal is sampled by the sampling circuit. To avoid missing the sand production signal, the sampling frequency is 40 MHz. The amount of data is large, and the collected signal contains both valid signals and invalid signals.

[0044] For the input data calculation unit after sampling, the digital filtering module first performs digital filtering to filter out the ultrasonic signal emitted by the erosion sensor 2.

[0045] To avoid interference from the signal emitted by the erosion sensor 2 and filter the sand production signal, a 16th-order FIR filter is used for digital filtering. This filter has an accurate linear phase response and will not cause phase distortion of the signal. Its implementation method is non-recursive, so it is always stable, and the system quantization error and rounding noise are small. The frequency band range of the FIR filter is 500 kHz - 1 MHz. This eliminates the interference from the signal emitted by the erosion sensor 11.

[0046] The FIR filter has the following specifications: filter type is band-pass, bandwidth is 100 KHz - 1 MHz, sampling frequency is 10 MHz, filter order is 16th order, input data width and output data width are 10 bits, system width is 12 bits, and window function type is Hamming. This eliminates the waveform interference of the erosion sensor 2 and is conducive to the sand production monitoring sensor 1 collecting valid data. As Figure 8 shown, the amplitude gain at 1 MHz frequency is -3 dB, meeting the system design requirements.

[0047] After filtering out the ultrasonic signal emitted by the erosion sensor 2, it is processed by the sand production signal detection module. If the sampled voltage value is much greater than the threshold voltage, the collected signal is considered valid and the data is stored in the storage chip. If it is less than the threshold voltage, it proves that the collected signal is invalid, indicating that the sand production signal is noise and there is no sand grain erosion on the pipe wall. This saves storage space for storing more valid data.

[0048] For sampling, the AD chip uses the AD9224 AD conversion chip. With a sampling rate as high as 40 MSPS and a resolution of 12 bits, it can achieve a good signal-to-noise ratio. It has a high-performance sample-and-hold amplifier inside, can output data directly in binary form, and can obtain a good signal-to-noise ratio, with very little interference to the signal, making it very suitable for sampling weak signals.

[0049] The storage chip K9K8G08U0M has a flash memory capacity of 8 Gbit and a spare space of 256 Mbit. Performing a write operation on a page of (2K + 64) Byte size usually takes 200 us, and performing an erase operation on a block of (128K + 4K) Byte size usually takes 1.5 ms. Data on the data register can usually be read out at a speed of 25 ns / byte.

[0050] After the sand production signal detection module confirms that the sand production signal is valid, the erosion sensor control module controls the erosion sensor 2 for transmitting signals to emit signals and starts timing. After the erosion sensor 2 responsible for receiving receives the corresponding signal, it stops timing and returns the time difference to the sand production rate and pipe wall calculation module to calculate the sand production rate and the pipe wall thickness.

[0051] As Figure 6 shown, the erosion sensor control module emits a sine signal, which is amplified by the signal processing unit to drive the erosion sensor 2 to emit signals. Another erosion sensor 2 receives the ultrasonic wave, which is amplified, filtered, and shaped into a square wave by the signal processing unit and then transmitted to the data calculation unit to end the timing.

[0052] As Figure 4 shown, there are multiple groups of the signal acquisition units, which are respectively connected to different gas well pipelines.

[0053] Each group consists of one sand production monitoring sensor 1 and two erosion sensors 2.

[0054] As Figure 7 shown, erosion sensor one, erosion sensor six, and sand production monitoring sensor one are in one group.

[0055] Each group of signal acquisition units includes one sand production monitoring sensor 1 and two erosion sensors 2, which are connected to different pipelines. Several groups of signal acquisition units are all connected to the same chassis, and a signal processing unit and a data calculation unit are arranged inside the chassis.

[0056] It further includes a first multiplexing module and a second multiplexing module. Both the first multiplexing module and the second multiplexing module are electrically connected to the data calculation unit. The sand production monitoring sensor 1 of each group of signal acquisition units is connected to the first multiplexing module, and the first multiplexing module is also electrically connected to the signal processing unit; the erosion sensor 2 for transmitting signals of each group of signal acquisition units is electrically connected to the second multiplexing module, and the second multiplexing module is electrically connected to the signal processing unit.

[0057] The sand production rate of multiple wells and the wall thickness of the weak parts are obtained simultaneously through the first multiplexing module and the second multiplexing module.

[0058] Since there are multiple groups of signal acquisition units, during use, all the sand production monitoring sensors 1 transmit signals to the first multiplexing module. Through the data calculation unit, a certain path of the first multiplexing module is selected to be turned on. For example Figure 7 if it receives the signal from the first sand production detection sensor, then the other sand production detection sensors 11 are not input into the data calculation unit. The erosion sensor 2 for transmitting signals corresponding to the first sand production detection sensor is the first erosion sensor. Then the second multiplexing module selects the path where the first erosion sensor is located to be turned on, so that the first erosion sensor emits a signal.

[0059] The signal acquisition unit is installed on the outer wall of the elbow of the gas well pipeline in the oncoming flow direction.

[0060] As Figure 4 shown, the three sensors are fixed to the outer wall of the elbow of the gas well pipeline by a clamp at about twice the diameter in the oncoming flow direction. This installation position is the sensitive position where sand grains are most likely to collide with the pipe wall and is also the position where the wall thickness decreases most severely.

[0061] As Figure 2 and Figure 3 shown, the signal acquisition unit further includes a housing 3. The erosion sensor 2 and the sand production monitoring sensor 1 are installed in the housing 3.

[0062] The three sensors are all placed in the same housing 3, and the two erosion sensors 2 are adjacent, and the sand production monitoring sensor 1 is located on one side of the two erosion sensors 2.

[0063] It further includes a sound insulation layer 4. The two erosion sensors 2 are respectively connected to both sides of the sound insulation layer 4. The erosion sensor 2 includes a damping block 5, a piezoelectric ceramic wafer 6, and a delay block 7. The bottom of the delay block 7 is parallel to the ground of the housing 3. The top of the delay block 7, on the side in contact with the sound insulation layer 4, is higher than the opposite side. The top of the delay block 7 is connected to the piezoelectric ceramic wafer 6, and the damping block 5 is connected to the delay block 7 and wraps the piezoelectric ceramic wafer 6.

[0064] Further, two independent erosion sensors 2 can be made into a transceiver integrated erosion sensor, with a sound insulation layer 4 sandwiched between the two erosion sensors 2. Moreover, the piezoelectric ceramic wafers 6 of the two sensors are both inclined downward towards the sound insulation layer 4 to form an angle, making the reflected ultrasonic signals more concentrated and facilitating the reception of the signals emitted by the other erosion sensor 2.

[0065] The transducers of the two erosion sensors 2 are arranged on the same plane without an angle between them, and they have a wide applicable wall thickness range.

[0066] As Figure 1 shown, a method for integrated monitoring of sand production and erosion in a gas well includes the following steps.

[0067] The sand production monitoring sensor 1 monitors the ultrasonic waves caused by sand grains colliding with the pipe wall. After the sand production signal is output, amplified, filtered, and collected, it is transmitted to the data calculation unit. The data calculation unit monitors whether the sand production signal is valid. If it is valid, the data calculation unit controls the ultrasonic erosion monitoring sensor to start working. If it is invalid, it is considered that there is no sand and gravel erosion.

[0068] The erosion sensor 2 monitors. The data calculation unit controls one erosion sensor 2 to emit an ultrasonic signal and start timing. After the other erosion sensor 2 receives the corresponding ultrasonic signal, it stops timing, and returns the time difference to the data calculation unit to calculate the wall thickness and sand production rate.

[0069] Through the data calculation unit, control a certain path of the first multiplexing module to conduct, transmit the output signal of one sand production monitoring sensor 1 to the data calculation unit, and control the second multiplexing module to connect to the erosion sensor 2 in the same group as the sand production monitoring sensor 1. This erosion sensor 2 receives the control signal of the data calculation unit and emits ultrasonic waves.

[0070] A number of passively monitored sand production monitoring sensors 1 input the sand production signals into the first multiplexing module (specifically a multiplexing circuit). The data calculation unit, that is, the microcontroller unit MCU, selects to receive the signal of a certain sand production monitoring sensor 1. The signal of this sand production sensor first undergoes amplification and filtering through the signal processing unit, specifically processed using an amplification and filtering circuit, and then the voltage of the sand production signal is collected through the data acquisition circuit.

[0071] The MCU filters through the digital filtering module and then determines whether the sand production signal is greater than the threshold voltage. Otherwise, it is considered that there are no sand grains in the pipeline, and the sand production monitoring sensor 1 continues to monitor.

[0072] If it is determined that there are sand grains, the MCU controls the second multiplexing module to switch, and switches to the erosion sensor 2 in the same signal acquisition unit as the sand production monitoring sensor 1 to emit a signal. Specifically, the MCU controls the signal generation circuit to send a signal. The output of the signal generation circuit is amplified and driven by the amplification drive circuit, and then passes through the second multiplexing module and the impedance matching circuit (to ensure maximum power transmission of the signal), and is input into the erosion sensor 2 to control the erosion sensor 2 to start and start timing.

[0073] For example, if the signal of the sand production monitoring sensor 1 in the first group is selected to be received, the second multiplexing module is turned on to the erosion sensor 2 for transmission in the first group.

[0074] After another erosion sensor 2 in the same signal acquisition unit receives the emitted ultrasonic signal, it stops timing, and calculates the wall thickness according to the time difference between transmission and reception.

[0075] The MCU transmits the calculation result to the host computer as needed.

[0076] Specifically, as Figure 5 shown, A is the erosion sensor 2 that emits the signal, and B is the erosion sensor 2 that receives the signal.

[0077] The signal emitted by A is reflected by the inner wall of the pipeline and received by B. Let the propagation speed of ultrasonic waves in the pipe wall be V, and the time from A to emit ultrasonic waves to B to receive ultrasonic waves be t. is the angle between the outer wall of the pipeline and the ultrasonic wave propagation direction 10, then the wall thickness D of the pipe wall is

[0078]

[0079] When the installation distance between sensor A and sensor B is very small, close to 90°, close to 1, the pipe thickness D can be approximately equal to:

[0080]

[0081] For the sand production rate,

[0082] Since the sand grains have a certain kinetic energy under the carrying of the fluid, when the sand grains move to the elbow of the pipeline with the fluid, they will impact the pipe wall, causing high-frequency vibration of the pipe wall, which is then converted into a continuous pulsed vibration signal generated by the sensor, that is, the sand production signal. The sand production rate is calculated based on the following theoretical model. Let m i be the mass of the i-th solid particle, which is less than the mass of the fluid. The average peak-to-peak voltage (signal intensity) output by the detector is related to the effective time change rate of the vibration kinetic energy generated by the sand grains hitting the inner wall of the gas pipeline, and the relationship is as follows:

[0083]

[0084] where S is the average power of the signal, and m i is the effective mass of the i-th solid particle; v i is the velocity of the i-th solid particle; n is the number of sand grains hitting the detector tube wall within a period of time; ΔT is the observation time period; β is the sensitivity of the sensor. Since the magnitude of the kinetic energy generated by the sand grains hitting the oil pipeline wall is related to the flow rate, flow velocity of the fluid in the pipeline, and the cross-sectional area of the fluid, assuming n sand grains collide with the pipe wall, the total mass of the sand grains colliding with the pipe wall is M, and the average velocity of the n sand grains is V, then the power of the output signal determined by the kinetic energy of the sand grains and the sensitivity of the sensor is:

[0085]

[0086] Since the magnitude of the kinetic energy generated by the sand grains hitting the oil pipeline wall is related to the flow rate, flow velocity of the fluid in the pipeline, and the cross-sectional area of the fluid, within the observation time ΔT, the instantaneous flow rate Q of the fluid is a constant, and the average velocity of the sand grains is approximately equal to the flow velocity of the fluid in the pipeline, that is, V = Q / A, where A is the cross-sectional area of the fluid. Substituting it into the above formula (4), we get:

[0087]

[0088] In addition, according to Parseval's theorem, the average power of the sand production signal within ΔT is:

[0089]

[0090] where U represents the voltage sampling value of the sand production signal of the sensor; Δt represents the sampling interval. According to formula (5) and formula (6), the total mass of the sand grains flowing through the pipeline within the observation time ΔT is:

[0091]

[0092] Since the mass flow rate M t is the mass of the fluid flowing through any cross-section of the pipeline per unit time. The unit is kg / s, that is

[0093]

[0094] The total mass of sand production has been calculated in formula (7). Given the time ΔT, the sand production rate is calculated through formula (8). That is:

[0095]

[0096] When conducting experiments, the cross-sectional area A of the pipeline is determined. The instantaneous flow rate Q of the fluid can be measured by a Doppler flowmeter. Whether it is ΔT or t is determined by the sampling rate of the data acquisition circuit. In this way, the amount of sand can be calculated by detecting the output voltage value of the sensor. The sand detection sensor uses the piezoelectric effect of the ultrasonic sensor to detect signals. Therefore, the sensitivity of the sensor refers to the ratio of the output electric quantity of the sensor to the external force it bears. The value of β can be calibrated through experiments.

Claims

1. An integrated monitoring system for sand production and erosion in gas wells, characterized by: include, The signal collection unit comprises a sand monitoring sensor (1) for receiving ultrasonic signals caused by sand particles hitting the pipe wall, and two erosion sensors (2) for transmitting pulse signals and receiving echo signals from the inner wall of the pipe, one of which is used for transmitting signals and the other for receiving signals; the sensitive surfaces of the three sensors are located on the same plane; A signal processing unit is used to amplify and filter the output signal of the sand production monitoring sensor (1), amplify, filter and shape the output signal of the erosion sensor (2) receiving the signal, and amplify the signal of the erosion sensor (2) transmitting the signal; The data calculation unit comprises a digital filtering module for filtering out interference signals of the erosion sensor (2) in the sand production signal; a sand production signal detection module for analyzing whether the output signal is valid after receiving the output signal of the sand production monitoring sensor (1); an erosion sensor control module for controlling an erosion sensor (2) to emit ultrasonic waves and count time, and to stop counting when another erosion sensor (2) receives the ultrasonic waves to obtain a time difference; and a sand production rate and pipe wall calculation module for calculating the sand production rate and pipe wall thickness through the output voltage value of the sand production signal and the time difference detected by the erosion sensor (2).

2. The integrated monitoring system for sand production and erosion in a gas well according to claim 1, characterized in that: There are a plurality of signal acquisition units, which are respectively connected to different gas well pipelines.

3. The integrated monitoring system for sand production and erosion in a gas well according to claim 2, characterized in that: The invention also comprises a first multi-way switching module and a second multi-way switching module, wherein the first multi-way switching module and the second multi-way switching module are both electrically connected to the data calculation unit, the sand production monitoring sensor (1) of each group of signal acquisition units is connected to the first multi-way switching module, and the first multi-way switching module is also electrically connected to the signal processing unit; the erosion sensor (2) used for transmitting signals of each group of signal acquisition units is electrically connected to the second multi-way switching module, and the second multi-way switching module is electrically connected to the signal processing unit.

4. A gas well sand production and erosion integrated monitoring system according to claim 1 or 2, characterized in that: The signal acquisition unit is installed on the outer wall of the gas well pipeline elbow in the incoming flow direction.

5. The integrated monitoring system for sand production and erosion in a gas well according to claim 1, characterized in that: The frequency range of the output signal of the sand production monitoring sensor (1) is 100kHz-500kHz, and the emission signal of the erosion sensor (2) is a sine wave with a frequency of more than 1MHz.

6. The integrated monitoring system for sand production and erosion in a gas well according to claim 1, characterized in that: The signal acquisition unit further comprises a housing (3), and the erosion sensor (2) and the sand production monitoring sensor (1) are installed in the housing (3).

7. The integrated monitoring system for sand production and erosion in a gas well according to claim 6, characterized in that: It also includes a sound insulation layer (4), two erosion sensors (2) are respectively connected to both sides of the sound insulation layer (4), the erosion sensor (2) includes a damping block (5), a piezoelectric ceramic chip (6) and a delay block (7), the bottom of the delay block (7) is parallel to the ground of the housing (3), the top of the delay block (7), the side in contact with the sound insulation layer (4) is higher than the other side opposite, the top of the delay block (7) is connected to the piezoelectric ceramic chip (6), and the damping block (5) is connected to the delay block (7) and wraps the piezoelectric ceramic chip (6).

8. A method for integrated monitoring of sand production and erosion in a gas well according to any one of claims 1 to 7, characterized in that: The following steps are included: The sand-generating monitoring sensor (1) monitors the ultrasonic wave induced by the collision of sand particles with the pipe wall, outputs the sand-generating signal, and transmits it to the data calculation unit after amplification, filtering and collection. The data calculation unit monitors whether the sand-generating signal is valid. If it is valid, the data calculation unit controls the ultrasonic erosion monitoring sensor to start working. If it is invalid, it is considered that there is no sand erosion; The erosion sensor (2) monitors, the data calculation unit controls one erosion sensor (2) to emit an ultrasonic signal and start timing, and the other erosion sensor (2) stops timing after receiving the corresponding ultrasonic signal, and returns the time difference to the data calculation unit to calculate the wall thickness and sand production rate.

9. A gas well sand production and erosion integrated monitoring method according to claim 8, characterized in that: The data calculation unit controls a certain path of the first multi-path switching module to be turned on, transmits an output signal of a sand production monitoring sensor (1) to the data calculation unit, and controls the second multi-path switching module to be connected to an erosion sensor (2) in the same group as the sand production monitoring sensor (1), and the erosion sensor (2) receives the control signal of the data calculation unit and emits an ultrasonic wave.

Images