Shale gas fracturing micro-seismic real-time intelligent monitoring and early warning system

Abstract

The invention discloses a shale gas fracturing micro-seismic real-time intelligent monitoring and early warning system, which relates to the technical field of crack effectiveness monitoring and risk early warning in shale gas exploitation fracturing engineering, and comprises a sensor array for capturing stratum signals and a signal processing unit, the system further comprises a five-element coupling sensor array, a tracer agent injection and synchronous acquisition subsystem, a five-element feature decoupling unit, a crack effectiveness comprehensive judgment module and a real-time feedback regulation and control module. According to the invention, a five-element coupling sensor array is used for synchronously collecting multi-dimensional signals, tracer agent specific reaction linkage, a five-element feature decoupling algorithm and a quantitative judgment and real-time feedback regulation and control mechanism are used; the problems that a gas-bearing layer and a non-gas-bearing layer are difficult to distinguish through traditional micro-seismic monitoring, weak signals are prone to being interfered, crack effectiveness judgment is fuzzy, and invalid fracturing is caused by a monitoring blind area are solved, and effective crack accurate recognition, monitoring coverage range expansion, interference misjudgment rate reduction and fracturing strategy dynamic optimization are achieved.

Description

Technical Field

[0001] This invention relates to the field of fracture effectiveness monitoring and risk early warning technology in shale gas fracturing engineering, specifically a real-time intelligent monitoring and early warning system for microseismic vibration in shale gas fracturing. Background Technology

[0002] In shale gas extraction, fracturing operations, which involve injecting fracturing fluid under high pressure to create an artificial fracture network, are a core component for achieving efficient shale gas extraction. Real-time intelligent microseismic monitoring and early warning systems, as a key technology for evaluating fracturing effectiveness and managing risks, function by capturing microseismic signals generated by formation rock fracturing during the fracturing process using sensor arrays deployed downhole or on the surface. Through signal processing and location inversion, the systems monitor the extent, morphology, and intensity of fracture propagation in real time, providing a basis for adjusting fracturing parameters and issuing early warnings for construction safety.

[0003] Existing microseismic monitoring systems all operate primarily on a passive reception model: relying on microseismic signals spontaneously generated by the formation under fracturing conditions, and analyzing characteristics such as signal amplitude, frequency, and arrival time difference to invert the spatial distribution parameters of fractures. However, this model has significant technical limitations: First, it cannot accurately determine whether fractures have reached effective gas-bearing layers. The rock mechanical properties of gas-bearing layers and non-gas-bearing layers (such as dry or aquifer layers) are relatively similar, and the characteristics (such as energy and frequency) of their generated microseismic signals overlap significantly. It is difficult to effectively distinguish them using only passively received microseismic signals, leading to ineffective fracturing phenomena where fractures have expanded but have not reached gas-bearing layers, resulting in a large waste of fracturing fluid, proppant, and other resources. Second, due to the heterogeneity of the formation, the spontaneous microseismic signals in some areas are weak in intensity and have a low signal-to-noise ratio, making them easily masked by mechanical interference generated by fracturing operations, further reducing the accuracy of fracture effectiveness assessment.

[0004] Currently, the industry generally believes that microseismic signals are a product of passive formation response, and monitoring systems can only act as signal receivers. This results in a persistent technical bottleneck in determining the effective extension of fractures in existing systems, making it difficult to meet the actual needs of efficient and economical shale gas extraction. Therefore, this paper proposes a real-time intelligent monitoring and early warning system for shale gas fracturing microseismic activity to overcome these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a real-time intelligent monitoring and early warning system for microseismic fracturing in shale gas, in order to solve the problems mentioned in the background art.

[0006] To address the aforementioned technical problems, the present invention provides a real-time intelligent monitoring and early warning system for microseismic monitoring of shale gas fracturing, comprising a sensor array and a signal processing unit for capturing formation signals.

[0007] It also includes a five-element coupled sensor array, a tracer injection and synchronous acquisition subsystem, a five-element feature decoupling unit, a crack effectiveness comprehensive judgment module, and a real-time feedback control module;

[0008] A five-element coupled sensor array is deployed in the formation surrounding the fracturing well to simultaneously acquire five-element signals: microseismic, fracturing fluid conductivity, acoustic impedance, tracer reaction infrared radiation, and fracturing fluid flow noise. The tracer injection and synchronous acquisition subsystem injects tracer according to a preset method and synchronizes with the five-element signal acquisition. The five-element feature decoupling unit performs interference removal, feature extraction, and weak signal enhancement on the five-element signals. The fracture effectiveness comprehensive judgment module outputs a matching degree index based on the five-element signal features to determine the fracture effectiveness. The real-time feedback control module dynamically adjusts the fracturing parameters and injection strategy according to the judgment results.

[0009] Furthermore, the five-element coupled sensor array integrates a microseismic detection unit, a fracturing fluid conductivity detection unit, an acoustic impedance modulation unit, a tracer and gas reaction detection unit, and a fracturing fluid flow noise detection unit. Each unit is encapsulated in a corrosion-resistant metal shell. The sensor array is distributed in an equilateral triangle pattern in the formation 30 to 80 meters around the fracturing well, with a spacing of 5 meters between adjacent sensors.

[0010] Furthermore, the tracer injection and synchronous acquisition subsystem uses a 5‰ concentration of perfluorohexane microemulsion as a tracer, which is injected in a pulse every 5 minutes along with the fracturing fluid, with a single injection volume of 1% of the fracturing fluid discharge. The five-element signal acquisition timestamp error is less than 10ns through downhole clock synchronization, forming an event-physical-chemical-fluid five-element correlation data package.

[0011] Furthermore, the five-element feature decoupling unit eliminates interference signals by constructing a five-element signal consistency index. When the time difference between the microseismic signal and the other four types of signals is greater than 5ms or the amplitude correlation is less than 0.3, it is determined to be an interference signal and eliminated.

[0012] Furthermore, a five-element feature decoupling unit is used to construct a five-element feature matrix for gas-bearing and non-gas-bearing layers, wherein the infrared radiation intensity of the gas-bearing layer is greater than 0.8 μW / cm². 2 The fracturing fluid conductivity is less than 0.5 S / m, the acoustic impedance reflectivity is greater than 30%, and the infrared signal lags behind the micro-vibration signal by 0.5 ms to 1 ms.

[0013] Furthermore, for weak micro-seismic signals with a signal-to-noise ratio of less than 5dB, the five-element feature decoupling unit adopts an infrared-flow noise dual anchoring strategy, using the peak position of infrared radiation and the center of gravity of flow noise energy as anchor points. When the spatial deviation between the two anchor points is less than 0.2 meters, the signal within 100ms is superimposed through the feature anchoring-coherent superposition algorithm, amplifying the amplitude by 80 to 120 times, and performing phase compensation based on the frequency characteristics of flow noise.

[0014] Furthermore, the fracture validity comprehensive judgment module outputs a five-element matching degree index from 0 to 100. When the index is ≥80, it is judged as a valid fracture, which must meet the following requirements: infrared and microseismic energy delay time of 0.5ms to 1ms, fracturing fluid conductivity of less than 0.5S / m, acoustic impedance reflectivity of greater than 30%, spatial deviation of double anchor points of less than 0.2 meters, and spatial coordinate deviation of five-element signals of less than 0.3 meters. An index of 50 to 80 is a fracture to be verified, and an index of less than 50 is an invalid fracture.

[0015] Furthermore, the real-time feedback control module employs a tracer enhancement injection strategy for ineffective crack areas, increasing the tracer concentration to 1% and injecting a 2% concentration of diverting agent when there is no infrared signal. When the infrared signal in a certain area drops by more than 50% within 10 seconds and the flow noise frequency jumps to above 2kHz, a safety warning control of reducing the pump pressure by 5% is triggered.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. Accurately distinguish between gas-bearing and non-gas-bearing strata to reduce the risk of ineffective fracturing:

[0018] Relying on a five-element coupled sensor array to collect multi-dimensional signals from mechanics, physics, chemistry, and fluid dynamics, combined with a five-element characteristic matrix specific to gas-bearing layers (infrared radiation intensity > 0.8 μW / cm²), 2 (e.g., conductivity <0.5S / m), effectively solving the problem that traditional single microseismic signals are difficult to distinguish stratum properties.

[0019] By utilizing the specific infrared reaction between tracers and methane, combined with signal lag time determination, ineffective fracturing that fails to reach the gas-bearing layer during fracture propagation can be avoided, thus reducing the waste of resources such as fracturing fluid and proppant.

[0020] 2. Enhance weak signal identification capabilities and expand monitoring coverage:

[0021] For weak micro-seismic signals with a signal-to-noise ratio of <5dB, an infrared-flow noise dual-anchoring strategy and a feature anchoring-coherent superposition algorithm are adopted to amplify the signal amplitude by 80-120 times while keeping the phase error within 2°.

[0022] This addresses the problem of weak signals being masked by interference due to formation heterogeneity, enabling precise capture of low-intensity rupture events and avoiding monitoring blind spots.

[0023] 3. Enhance interference signal removal and improve judgment accuracy:

[0024] A five-element signal consistency index was constructed, and mechanical interference signals such as pump vibration and tubing vibration were accurately eliminated by dual judgment of time difference (>5ms) and amplitude correlation (<0.3).

[0025] The error rate of interference signals has been reduced to below 0.3%, which is a further improvement over traditional filtering technology and quaternary signal mechanism, ensuring the reliability of crack monitoring data.

[0026] 4. Quantify the effectiveness of crack assessment to provide a clear basis for decision-making:

[0027] It outputs a five-element matching degree index of 0-100, clearly distinguishing effective cracks (≥80), cracks to be verified (50-80), and invalid cracks (<50), replacing the traditional fuzzy judgment method.

[0028] The judgment criteria include multi-dimensional quantitative indicators, providing an intuitive and quantifiable reference for fracturing effect evaluation and reducing human judgment errors.

[0029] 5. Real-time dynamic adjustment of fracturing strategy to optimize extraction efficiency and safety:

[0030] For ineffective fracture areas, tracer-enhanced injection or diverting agent guidance can be implemented, and fracturing parameters can be dynamically adjusted to increase the probability of effective fracture extension.

[0031] New warning indicators for sudden drops in infrared signals and abnormal flow noise have been added, triggering pump pressure fine-tuning (reduction by 5%) to prevent the risk of cracks entering the water layer and blocking the gas-bearing layer, thus ensuring construction safety.

[0032] 6. Expand monitoring capabilities for special scenarios and improve the monitoring system:

[0033] For scenarios where gas-bearing rocks are highly resilient and lack significant micro-vibrations, the main channel of a fracture can be directly identified by combining the low-frequency fluctuation characteristics of flow noise with infrared signals, and the positioning error is controllable.

[0034] By leveraging the amplitude decay rate and frequency distribution of flow noise, fracture permeability can be inverted in real time, providing a quantitative basis for adjusting proppant concentration and facilitating efficient mining. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the real-time intelligent monitoring and early warning system for micro-vibrations in shale gas fracturing according to the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figure 1 The present invention provides a technical solution:

[0038] See Figure 1 The following is an example of a real-time intelligent monitoring and early warning system for microseismic fracturing in shale gas:

[0039] I. System:

[0040] 1. Five-element coupled sensor array:

[0041] Based on the microseismic detection unit, fracturing fluid conductivity detection unit, acoustic impedance modulation unit, and tracer and gas reaction detection unit, the array also includes a fracturing fluid flow noise detection unit. Each unit is integrated and encapsulated in a corrosion-resistant metal shell, which is resistant to 150°C and 100MPa.

[0042] Microseismic detection unit: Employs piezoelectric crystals with an operating frequency range of 10Hz to 10kHz, used to capture microseismic signals generated by rock fracturing;

[0043] Fracturing fluid conductivity detection unit: It adopts a ring electrode with a range of 0.1 to 10 S / m and is used to monitor the diffusion conductivity of fracturing fluid in the formation in real time.

[0044] Acoustic impedance modulation unit: It adopts a high-frequency acoustic wave transmitter with an operating frequency of 100kHz to 1MHz, which is used to actively transmit modulated acoustic waves and receive reflected signals to obtain acoustic impedance characteristics.

[0045] The tracer and gas reaction detection unit consists of a miniature infrared spectral sensor and a temperature compensation module. The infrared spectral sensor detects at a wavelength of 3.3 μm (corresponding to the characteristic absorption peak of the reaction product of methane and tracer), and the temperature compensation module is used to eliminate the influence of fracturing fluid temperature fluctuations on the detection results.

[0046] Fracturing fluid flow noise detection unit: Employs a miniature hydrophone with an operating frequency of 20Hz to 2kHz to capture turbulent noise generated by fracturing fluid flowing in the fracture (fractures in gas-bearing strata form non-uniform flow channels due to gas obstruction, and their noise characteristics differ significantly from those in non-gas-bearing strata).

[0047] The sensor array is distributed in an equilateral triangle pattern in the formation 30 to 80 meters around the fractured well, with a 5-meter spacing between adjacent sensors to ensure no blind spots in signal coverage.

[0048] 2. Tracer Injection and Synchronous Acquisition Subsystem:

[0049] Tracer selection and injection method: Perfluorohexane microemulsion was used as the tracer at a concentration of 5‰, injected in a pulsed manner with the fracturing fluid, once every 5 minutes, with a single injection volume of 1% of the fracturing fluid discharge. The perfluorohexane microemulsion interacts specifically with methane in the gas-bearing reservoir under high pressure, producing stable infrared characteristic radiation in the 3.3μm band; it does not react with aqueous layers (no methane) or dry layers (no fluid interaction).

[0050] Acquisition synchronization mechanism: By synchronizing with the downhole clock, it is ensured that when the microseismic signal is triggered, the fracturing fluid conductivity, acoustic impedance, infrared radiation intensity and flow noise signal at the corresponding location are acquired synchronously, with a timestamp error of less than 10ns, forming an event-physical-chemical-fluid five-element correlation data package.

[0051] 3. Five-element feature decoupling unit:

[0052] This unit implements feature extraction and interference removal for five-element signals through an algorithm. The specific steps are as follows:

[0053] Step 1: Interference signal removal:

[0054] Mechanical interference signals (such as pump vibration and tubing vibration) only produce signals similar to micro-vibration waveforms, but do not cause sudden changes in fracturing fluid conductivity (no fracturing fluid diffusion caused by fracture propagation), do not cause local changes in acoustic impedance (no rock interface change), do not produce infrared radiation peaks (no reaction between methane and tracer), and do not form flow noise characteristics that match the fracture morphology (only uniform background noise).

[0055] A five-element signal consistency index is constructed. When the time difference between the microseismic signal and the fracturing fluid conductivity signal, acoustic impedance signal, infrared radiation signal, and flow noise signal is greater than 5 ms or the amplitude correlation is less than 0.3, it is identified as an interference signal and eliminated. This method improves the interference elimination rate compared to traditional filtering techniques.

[0056] Step 2: Constructing the gas-bearing layer feature matrix:

[0057] The five-element characteristics of gas-bearing and non-gas-bearing layers differ significantly, as detailed below:

[0058] In terms of microseismic energy, the gas-bearing layer has an energy level of 10. 3 Up to 10 4 J, frequency 1kHz to 5kHz and dispersed; water layer greater than 10 4 J, with frequencies concentrated between 2kHz and 3kHz; dry layer less than 10 3 J, frequency less than 1kHz.

[0059] Regarding the electrical conductivity of fracturing fluid, it is less than 0.5 S / m in gas-bearing layers (gas blockage causes fracturing fluid diffusion to be slow); greater than 1.0 S / m in water-bearing layers (fracturing fluid diffusion is fast); and about 0 in dry layers (no fracturing fluid diffusion).

[0060] In terms of acoustic impedance reflectivity, the reflectivity is greater than 30% in gas-bearing layers (strong reflection at the gas-liquid interface); and less than 10% in non-gas-bearing layers (weak reflection at the water-solid or solid-solid interface).

[0061] Regarding infrared radiation intensity (3.3 μm), the gas-bearing layer has an intensity greater than 0.8 μW / cm².2 (Methane reacts with the tracer); non-gas-bearing layers have a density less than 0.1 μW / cm². 2 (No response)

[0062] Regarding flow noise, the gas-bearing layer has a frequency of 20Hz to 500Hz with an amplitude fluctuation greater than 30% (non-uniform flow channels lead to turbulent instability); the water layer has a frequency of 500Hz to 2kHz with an amplitude fluctuation less than 10% (uniform flow channels lead to turbulent stability); and the dry layer has no obvious flow noise (no fracturing fluid flow).

[0063] By introducing infrared radiation and microseismic energy delay time parameters, the infrared signal lags behind the microseismic signal by 0.5ms to 1ms due to the propagation of cracks in gas-bearing strata leading to methane escape; non-gas-bearing strata have no lag or a lag time greater than 5ms, thus solving the problem of confusion between similar microseismic characteristics and different stratigraphic properties.

[0064] Step 3: Enhancement of weak microseismic signals:

[0065] For microseismic signals with a signal-to-noise ratio of less than 5 dB (which cannot be identified by traditional methods), an infrared-flow noise dual-anchoring strategy is adopted:

[0066] a. The location of the infrared radiation peak is taken as the first anchor point (the location where the reaction occurs is the core region of the crack);

[0067] b. Extract the energy centroid position of the flow noise signal as the second anchor point (the point where the flow noise is strongest is the main channel of the crack);

[0068] c. Calculate the spatial deviation between the two anchor points. If the deviation is less than 0.2 meters, then take the geometric center of the two anchor points as the reference and use the characteristic anchoring-coherent superposition algorithm to superimpose the weak and micro-seismic signals within 100 ms in the spatial dimension, amplifying the amplitude by 80 to 120 times. At the same time, the signal phase is calibrated by the frequency characteristics of the flow noise (the low-frequency component of the gas layer flow noise is dominant, with a phase compensation of 5° to 10°; the high-frequency component of the non-gas layer flow noise is dominant, with a phase compensation of 1° to 3°), ensuring that the phase error of the superimposed signal is less than 2°, thus solving the positioning deviation problem caused by traditional superposition.

[0069] 4. Comprehensive Crack Validity Assessment Module:

[0070] This module outputs a five-element matching index (range 0 to 100), with the following criteria:

[0071] When the five-element matching degree index is greater than or equal to 80, it is judged as a valid fracture, which must simultaneously meet the following conditions: the delay time of infrared radiation and microseismic energy is within the range of 0.5ms to 1ms; the conductivity of fracturing fluid is less than 0.5S / m and the acoustic impedance reflectivity is greater than 30%; the spatial deviation of the infrared-flow noise dual anchor points is less than 0.2 meters; and the spatial coordinate deviation of the five-element signal is less than 0.3 meters.

[0072] When the quinary matching index is between 50 and 80, it is determined to be a crack to be verified, and additional tracer injection verification is required.

[0073] When the five-element matching degree index is less than 50, it is judged as an invalid crack.

[0074] 5. Real-time feedback control module:

[0075] For ineffective fracture areas, in addition to adjusting fracturing parameters, a tracer-enhanced injection strategy is adopted: in suspected non-gas-bearing areas, the tracer concentration is increased to 1%. If there is still no infrared signal, the diverting agent injection is immediately initiated with a diverting agent concentration of 2% to guide the fracture to change direction.

[0076] The safety warning system adds indicators for sudden drop in infrared radiation and abnormal flow noise: If the infrared signal intensity in a certain area drops by more than 50% within 10 seconds and the flow noise frequency suddenly jumps (>2kHz), it will warn that the crack is sealing the gas-bearing layer and entering the water layer, triggering pump pressure fine-tuning, and the pump pressure will decrease by 5%.

[0077] II. Workflow:

[0078] 1. Synchronous acquisition of five-element signals:

[0079] During fracturing operations, perfluorohexane tracer is injected in a pulsed manner, and a sensor array monitors micro-vibration signals in real time. When a suspected rupture event is detected, the conductivity, acoustic impedance, infrared radiation intensity, and flow noise signals of the fracturing fluid at that location are collected simultaneously to form a five-element correlation data of mechanics, fluid, acoustics, chemistry, and flow.

[0080] 2. Interference Removal and Feature Extraction:

[0081] The five-element signal consistency index is used to eliminate pure mechanical interference (without chemical, fluid, acoustic and flow characteristics); the microseismic signals of gas-bearing and non-gas-bearing layers are distinguished by infrared radiation intensity, hysteresis time and flow noise characteristics (gas-bearing layers have specific infrared response, fixed hysteresis law and low frequency fluctuation noise).

[0082] 3. Weak signal enhancement and positioning:

[0083] For weak microseismic signals, the spatial position is calibrated by infrared-flow noise dual anchor points, and the magnitude of the coherent signal is amplified by superimposing it; the crack propagation direction is inverted by combining the acoustic impedance gradient and the flow noise distribution, thus solving the problem of low positioning accuracy in traditional methods.

[0084] 4. Comprehensive judgment and feedback:

[0085] The effectiveness of fractures is determined by the five-element matching degree index, and fracturing parameters and tracer injection strategies are dynamically adjusted to avoid ineffective fracturing.

[0086] Summarize:

[0087] Fracturing fluid flow noise-assisted anchoring: The frequency and fluctuation characteristics of fracturing fluid flow noise in the fracture are used as a spatial positioning auxiliary reference, forming a dual anchoring mechanism with the infrared signal.

[0088] Phase compensation superposition algorithm: Based on the frequency characteristics of flowing noise, the phase of weak signal superposition is calibrated to keep the phase error within 2°, thus solving the signal distortion problem caused by traditional superposition.

[0089] Dual-anchor point spatial deviation verification: The authenticity of the crack is determined by the deviation between the infrared and the flow noise anchor point (a deviation > 0.2 meters is considered an invalid signal), further reducing the false judgment rate.

[0090] Crack channel identification under zero microseismic signal: When the gas-bearing rock is extremely tough (without significant microseismic activity), the main crack channel can be directly identified by combining the low-frequency fluctuation characteristics of flow noise (20Hz to 500Hz) with infrared signals, with a positioning error of less than 100%.

[0091] Real-time inversion of fracture permeability: By analyzing the amplitude decay rate and frequency distribution of flow noise, fracture permeability is calculated, providing a quantitative basis for adjusting proppant concentration.

[0092] The error rate of interference signals is further reduced: the five-element signal linkage elimination mechanism reduces the error rate of interference signals to below 0.3%, which is a further improvement compared to the four-element mechanism (0.5%).

Claims

1. A shale gas fracturing microseismic real-time intelligent monitoring and early warning system, comprising a sensor array for capturing formation signals and a signal processing unit, characterized in that: it further comprises a five-element coupled sensor array, a tracer injection and synchronous acquisition subsystem, a five-element feature decoupling unit, a fracture effectiveness comprehensive judgment module, and a real-time feedback regulation module; the five-element coupled sensor array is deployed in the formation around the fracturing well, and synchronously acquires five-element signals of microseismic, fracturing fluid conductivity, acoustic impedance, tracer reaction infrared radiation, and fracturing fluid flow noise; the tracer injection and synchronous acquisition subsystem injects tracers in a preset manner and synchronously with the five-element signal acquisition; the five-element feature decoupling unit performs interference rejection, feature extraction, and weak signal enhancement on the five-element signals; the fracture effectiveness comprehensive judgment module outputs a matching degree index based on the features of the five-element signals to determine the effectiveness of the fracture; and the real-time feedback regulation module dynamically adjusts the fracturing parameters and injection strategy according to the determination result. The five-element coupled sensor array integrates microseismic detection units, fracturing fluid conductivity detection units, acoustic impedance modulation units, tracer and gas reaction detection units, and fracturing fluid flow noise detection units, and each unit is packaged in a corrosion-resistant metal shell; the sensor array is distributed in the formation 30-80 meters around the fracturing well in an equilateral triangle, and the spacing between adjacent sensors is 5 meters. The tracer injection and synchronous acquisition subsystem uses a perfluorohexane microemulsion with a concentration of 5‰ as the tracer, which is injected in a pulse manner every 5 minutes with the fracturing fluid, and the single injection amount is 1% of the fracturing fluid displacement; The five-element signal acquisition time stamp error is less than 10 ns through downhole clock synchronization, forming event-physical-chemical-fluid five-element correlation data packets. The five-element feature decoupling unit rejects interference signals by constructing a five-element signal consistency index; when the time difference between the microseismic signal and the other four types of signals is greater than 5 ms or the amplitude correlation is less than 0.3, it is determined as an interference signal and is rejected. The five-element feature decoupling unit uses an infrared-flow noise double-anchoring strategy for weak microseismic signals with a signal-to-noise ratio less than 5 dB, taking the infrared radiation peak position and the flow noise energy center position as anchor points; when the spatial deviation of the two anchor points is less than 0.2 meters, the signals within 100 ms are superimposed through the feature anchoring-coherent superposition algorithm, the amplitude is amplified by 80 to 120 times, and the phase compensation is performed based on the flow noise frequency characteristics.

2. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: The fracture effectiveness comprehensive judgment module outputs a five-element matching degree index of 0 to 100; when the index is ≥80, it is determined as an effective fracture, which needs to meet the infrared and microseismic energy delay time of 0.5-1 ms, the fracturing fluid conductivity value of less than 0.5 S / m, the acoustic impedance reflectivity of more than 30%, the spatial deviation of the double anchor points of less than 0.2 meters, and the spatial coordinate deviation of the five-element signals of less than 0.3 meters; the index of 50-80 is a to-be-verified fracture, and less than 50 is an invalid fracture. 3.The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: The real-time feedback regulation module uses a tracer reinforcement injection strategy for invalid fracture areas, increases the tracer concentration to 1%, and injects 2% concentration of a steering agent when there is no infrared signal; when the infrared signal in a certain area decreases by more than 50% within 10 seconds and the flow noise frequency jumps to more than 2 kHz, a safety early warning regulation is triggered to reduce the pump pressure by 5%. ​ 4. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: ​ 5. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: The five-element feature decoupling unit constructs a five-element feature matrix of the gas-containing layer and the non-gas-containing layer, wherein the infrared radiation intensity of the gas-containing layer is greater than 0.8 μW / cm 2 The fracture fluid conductivity value is less than 0.5 S / m, the acoustic wave impedance reflectivity is greater than 30%, and the infrared signal lags behind the microseismic signal by 0.5 ms to 1 ms.

6. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: ​ 7. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: ​ 8. The shale gas fracturing microseismic real-time intelligent monitoring and early warning system of claim 1, wherein: ​

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