Hydraulic fracture monitoring method based on pumping curve fluctuation frequency

Abstract

The invention belongs to the technical field of rock mass engineering and oil and gas resource development, and discloses a hydraulic fracture monitoring method based on pump injection curve fluctuation frequency. According to the hydraulic fracture monitoring method, in the on-site fracturing process, the expansion degree and the fracture type of the hydraulic fracture in the reservoir are preliminarily judged by comparing the fluctuation degree of the on-site pump injection curve monitored in real time with the fluctuation degree of the test pump injection curve. According to the corresponding relation between the fluctuation degree of the pumping curve and the hydraulic fracture obtained through the method, the expansion degree and the fracture type of the hydraulic fracture in a fracturing site can be economically and efficiently judged, and the problems that fracture monitoring in previous fracturing engineering is greatly influenced by the environment and high in cost are solved. Therefore, the method can reduce the time and economic cost of hydraulic fracture field monitoring, and provides reference for unconventional oil and gas exploitation design and evaluation.

Description

Technical Field

[0001] The present invention belongs to the technical fields of rock mass engineering and oil and gas resource development, and relates to a hydraulic fracture monitoring method based on the fluctuation frequency of a pumping curve. Background Art

[0002] The efficient development of unconventional oil and gas resources is of great significance for alleviating the contradiction between world energy supply and demand and optimizing the world energy structure, and is also an important support for the rapid development of industry. Generally speaking, unconventional oil and gas mainly refer to shale oil and gas, tight oil and gas, coalbed methane, hydrates, heavy oil, oil sands, etc. Increasing the effective utilization and efficient development of unconventional low-grade resources has become one of the important guarantees for the development of the oil and gas industry. Since unconventional oil and gas resources such as tight oil and gas and shale oil and gas have characteristics such as low porosity and low permeability, industrial production capacity cannot be achieved without special reservoir stimulation measures. How to reduce the seepage resistance of unconventional oil and gas in the reservoir through artificial reservoir stimulation technology is one of the key issues in unconventional oil and gas development.

[0003] Hydraulic fracturing is a key technology for improving the recovery rate of resources in low-permeability reservoirs. With the increase in coal mining depth, hydraulic fracturing has been more widely used in managing hard roof disasters, preventing coal and gas outbursts, controlling rock burst pressure, and extracting coalbed methane (Electrical resistivity evolution and brittle failure of sandstone after exposure to different temperatures by Chao Lü et al.; CDEM-based simulation of the 3D propagation of hydraulic fractures in heterogeneous Coalbed Methane reservoirs by Qingshan Ren et al.). Hydraulic fracturing technology has greatly promoted the green, safe, and efficient exploitation of coal resources. However, the inability to accurately evaluate the scope and effectiveness of hydraulic fracturing may lead to blind spots. This may lead to rock burst pressure and coal and gas outburst disasters, posing significant safety risks to coal mining. Therefore, accurately monitoring the influence range of hydraulic fracturing, evaluating its effectiveness, and helping engineers adjust the fracturing plan to achieve efficient resource exploitation (Numerical analysis and geophysical monitoring for stability assessment of the Northwest tailings dam at Westwood Mine by Coulibaly Yaya et al.) has become a major challenge in current engineering practice.

[0004] In a laboratory environment, hydraulic fracturing is usually evaluated using techniques such as tracer methods, acoustic emission, CT scanning, and visual observation of fractures (Acoustic emission characterization of microcracking in laboratory-scale hydraulic fracturing tests by Jesse Hampton et al.; Hydraulic fracturing under high temperature and pressure conditions with micro CT applications: geothermal energy from hot dry rocks by W.G.P. Kumari et al.; Experimental and modeling investigation of fracture initiation from open-hole horizontal wells in permeable formations by Fanhui Zeng et al.). However, tracer methods and CT scanning are limited to providing descriptions of the final fractures after the experiment and cannot provide real-time monitoring of fracture propagation. Although the acoustic emission method can effectively locate fractures, it cannot capture changes in water content or fracture dynamics during the fracturing process, and it is difficult to apply these techniques to engineering practice. The most commonly used detection method in the fracturing field is microseismic monitoring: high-sensitivity seismic sensors installed underground or on the surface are used to capture tiny seismic waves. By analyzing these waveform signals, information such as the source location, magnitude, and occurrence time can be obtained to image hydraulic fractures in real time. In Hydraulic fracturing shear / tensile / compressive crack investigation using micro-seismic data by Li et al., microseismic source mechanisms are used to track in-situ stresses and evaluate high-frequency fracture effects, aiming to optimize reservoir stimulation and increase production. In Advanced deep learning for microseismic events prediction for hydraulic fracture treatment via continuous wavelet transform by Mohamed Adel Gabry et al., wavelet transform is used to monitor dynamic fracture events, and a deep learning model containing microseismic events is trained to predict fractures in each hydraulic fracturing operation. However, microseismic monitoring equipment is greatly affected by environmental factors, resulting in large monitoring errors. At the same time, the instrument cost is high, making it difficult to promote its use on a large scale.

[0005] Therefore, in view of the problems of high monitoring cost and great environmental influence in the real-time monitoring of hydraulic fractures at the hydraulic fracturing site, the present invention proposes a hydraulic fracture monitoring method based on the fluctuation frequency of the pumping curve. Based on the method of the present invention, by analyzing the fluctuation degree of the pumping curve collected during the fracturing process, the initiation and propagation of hydraulic fractures can be preliminarily judged, providing guidance for the evaluation of fracturing effects and the design of unconventional oil and gas exploitation. Summary of the Invention

[0006] The object of the present invention is to provide a hydraulic fracture monitoring method based on the fluctuation frequency of the pumping curve in view of the deficiencies in the above-mentioned existing technologies, so as to solve the problems of high cost of fracture monitoring and strong environmental sensitivity in on-site hydraulic fracturing engineering.

[0007] The technical solution of the present invention:

[0008] A hydraulic fracture monitoring method based on the fluctuation frequency of the pumping curve, the steps are as follows:

[0009] Collect surface outcrop rock samples of unconventional oil and gas reservoirs at the fracturing site, cut and polish the collected surface outcrop rock samples to make cube specimens; based on the hydraulic fracturing similarity criterion and on-site fracturing data, determine the diameter and length of the wellbore, the layout method of perforation clusters (perforation length, width, quantity and spacing), the layout method of fracturing sections (quantity and spacing of fracturing sections) and the flow rate and viscosity of the fracturing fluid;

[0010] Drill a wellbore in the center of the specimen, and excavate annular slots on the inner wall of the wellbore to simulate perforation clusters, and one annular slot represents one cluster of perforations; the wellbore is divided into fracturing sections and sealing sections, and the sealing sections separate the fracturing sections; among them, each fracturing section contains multiple clusters of perforations, and epoxy resin is used to form the sealing section to prevent the fracturing fluid from communicating between the fracturing sections; a plurality of water injection pipes are arranged at the fracturing sections, and the water injection pipes are respectively connected to a water pressure pump and a water pressure monitoring device to realize independent pump pressure monitoring of multiple fracturing sections; apply the in-situ stress corresponding to the unconventional oil and gas reservoir on the surface of the specimen, and after the specimen remains stable under the in-situ stress, install acoustic emission monitoring equipment on the surface of the specimen, and paste the acoustic emission probe on the surface of the specimen; finally, continuously inject fracturing fluid into the wellbore to simulate the fracturing process, and at the same time monitor the dynamic change process of the pumping curve during the fracturing process of multiple fracturing sections;

[0011] The fractured specimens were sectioned to observe the macroscopic propagation of hydraulic fractures inside the specimens. Meanwhile, the AF-RA method was used to process the acoustic emission monitoring data to judge the propagation degree and fracture type of hydraulic microfractures (shear fractures: fractures induced by shear stress and tensile fractures: fractures induced by tensile stress); Origin was used to visualize the fluctuation degree of the pumping curve and extract the dynamic change characteristics of the frequency and amplitude of the pumping curve; the fluctuation degree of the pumping curve at a single perforation cluster is proportional to the proportion of shear fractures during the propagation of hydraulic fractures. Therefore, the macroscopic and microscopic propagation of hydraulic fractures in the current unconventional oil and gas reservoirs can be reflected by the fluctuation degree of the pumping curve. For this reason, during the on-site fracturing process, the fluctuation degree of the on-site pumping curve monitored in real time was compared with that of the experimental pumping curve to preliminarily judge the propagation degree and fracture type of hydraulic fractures in the reservoir.

[0012] Advantages of the present invention: During the monitoring of the on-site propagation of hydraulic fractures, the present invention explores the fluctuation degree of the pumping pressure in unconventional oil and gas reservoirs, the severity of the propagation of hydraulic fractures, and the fracture type through physical simulation experiments. These data can be used as the basis for judging the relationship between the fluctuation degree of the pumping curve and the propagation of hydraulic fractures in on-site fracturing; then, the on-site pumping curve is obtained through on-site fracturing; finally, by comparing the fluctuation degrees of the on-site fracturing pumping curve and the experimental pumping curve, the propagation situation of the hydraulic fractures in the reservoir is determined. The corresponding relationship between the fluctuation degree of the pumping curve and the hydraulic fractures obtained by the method of the present invention can economically and efficiently determine the propagation degree and fracture type of hydraulic fractures in the fracturing field, and solves the problems of large environmental impact and high cost encountered in fracture monitoring in previous fracturing projects. Therefore, this method can reduce the time and economic costs of on-site monitoring of hydraulic fractures and provide a reference for the design and evaluation of unconventional oil and gas exploitation. Description of the Drawings

[0013] Figure 1 Schematic diagram of the physical similarity test of hydraulic fracturing and its fracture propagation analysis process provided by the embodiment of the present invention;

[0014] Figure 2 Schematic diagram of the method for processing acoustic emission monitoring data for determining the type of hydraulic microfractures provided by the embodiment of the present invention;

[0015] Figure 3 Detailed illustration of the pumping curve of test C1 and the proportion of the corresponding hydraulic microfracture types provided by the embodiment of the present invention;

[0016] Figure 4 Detailed illustration of the pumping curve of test C2 and the proportion of the corresponding hydraulic microfracture types provided by the embodiment of the present invention;

[0017] Figure 5It is a detailed illustration of the test C3 pumping curve provided by the embodiments of the present invention and the proportion of corresponding hydraulic microfracture types.

[0018] Figure 6 It is a detailed illustration of the test C4 pumping curve provided by the embodiments of the present invention and the proportion of corresponding hydraulic microfracture types

[0019] Figure 7 It is a detailed illustration of the test C5 pumping curve provided by the embodiments of the present invention and the proportion of corresponding hydraulic microfracture types. Detailed implementation manners

[0020] The following further illustrates the detailed implementation manners of the present invention in combination with the accompanying drawings and technical solutions.

[0021] Figure 1 It is a schematic diagram of the physical similarity test of hydraulic fracturing and its fracture propagation analysis process provided by the embodiments of the present invention, including:

[0022] Step 101, preparing a specimen for the physical similarity test of hydraulic fracturing.

[0023] (1) Selecting rock samples

[0024] The reservoir outcrop collected from the fracturing engineering site is transported to the processing plant and cut into rock samples of 300mm×300mm×300mm. After carefully observing the 6 surfaces of the rock samples, the rock samples with less through-surface cracks and better rock sample quality are selected as the drilled and slit specimens; according to the horizontal wellbore in the experimental scheme being parallel to the horizontal bedding, the drilling surface is determined and marked with a marker pen.

[0025] (2) Drilling position positioning of the rock sample

[0026] For the selected rock samples, the drilling position is determined by a square opening plate with a size of 300mm×300mm and a 25mm diameter circular hole excavated at the geometric centroid. The plate is covered on the rock sample plane to accurately determine the drilling diameter of 25mm and ensure that the drilling is at the center of the rock sample plane (i.e., ensure that the center of the drilling coincides with the centroid of the rock sample surface), and the drilling position is marked with a marker pen.

[0027] (3) Drilling cutter depth positioning of the drilling machine

[0028] After the drilling position on the rock sample surface is determined, the rock sample is transported to the drilling table with the drilling surface facing up. The downward drilling length of the drilling cutter is measured with a scale, and a horizontal line is marked with a marker pen at the designed wellbore length of the drilling cutter to ensure that the drilling depth of the rock sample reaches the wellbore length designed in the scheme. The wellbore length adopted in this example is shown in Table 1.

[0029] Table 1 Large true triaxial hydraulic fracturing test scheme

[0030]

[0031] (4) Drilling with a drilling machine

[0032] Adjust the position of the drilling machine so that the position of the drill bit is centered with the drilling mark on the surface of the rock sample. After centering, start water injection drilling. The water injection drilling process is as follows: 1. First, turn on the rotating switch of the drill tool to make the drill bit rotate. 2. Turn on the tap water faucet switch; one end of the yellow water pipe on the drilling machine is connected to the flowing tap water, and the other end discharges water from inside the hollow drill bit. 3. Turn on the down-drilling switch of the drill bit and operate the drill bit to drill down. 4. Stop drilling when the horizontal line mark at the drill bit is flush with the surface of the rock sample, and the drilling is completed. 5. After the drilling is completed, move the rock sample away from the drilling table for hole cleaning and inspection. 6. Remove the hollow drill bit from the drilling machine and take out the core.

[0033] Purposes of water injection drilling: 1. Cooling effect of water, the flowing water cools down the cutting drill bit to avoid tool damage. 2. Lubricating effect of water, which can ensure better drilling of the drill bit and make the wellbore wall smoother. 3. Carrying effect of water, during the drilling process, the core broken into particles and powder flows out with the flowing water in the hollow drill bit.

[0034] (5) Hole cleaning and inspection

[0035] For the core taken out from the drilled rock sample, part of the core that has broken into particles and powder flows out with the flowing water in the hollow drill bit; the other part of the core and debris remain adhered in the well hole. The core and residue stuck in the wellbore need to be removed with a special flat screwdriver, and the rock sample is turned over so that the well hole surface is on the side to allow the water injected into the well hole during drilling to flow out. After the core and residue are removed, measure the penetration depth of the flat screwdriver again to reach the designed wellbore length, so as to achieve the purpose of hole cleaning and inspection. After hole cleaning and inspection are completed, number the rock samples according to the experimental plan respectively.

[0036] (6) Grinding the cutter scale of the cutting machine

[0037] Grind the cutter scale of the cutting machine on the grinding machine according to the cutting slot positions in the experimental plan respectively for precise control. The cutting slot positions adopted in this example are shown in Table 1, and the cutting slot positions shown in the table are the vertical distances downward starting from the wellbore opening position. The process of grinding the cutter scale of the cutting machine is as follows: 1. First, fix the cutting slot tool on the grinding machine. 2. Use the intelligent digital measuring instrument of the grinding machine to position the cutting slot scale on the cutting slot tool. 3. Conduct at the positioned cutting slot scale of the tool.

[0038] (7) Drilling and cutting slots

[0039] After the cutter tool scale of the cutting machine is polished, carry the rock sample that has completed drilling onto the cutting table and fix it. Then install the cutter tool with the polished scale on the cutting machine. The slot cutting process is as follows: 1. Turn on the horizontal movement switch of the slot cutting tool of the cutting machine to align the slot cutting tool with the wellbore; 2. Turn on the vertical movement switch of the slot cutting tool of the cutting machine to make the first slot cutting tool scale flush with the surface of the rock sample to complete the leveling of the slot cutting tool scale; 3. Pour water into the well hole so that the water can cover the position where slot cutting is required. Turn on the rotation switch of the cutter tool of the cutting machine to make the cutter tool cut a circle in the well hole to complete the first slot. Repeat the above process for the second and subsequent slots until all slots are completed.

[0040] (8) Preserve the rock sample

[0041] After the slot cutting is completed, lay a sponge board on the ground to provide shock absorption and buffering to avoid damage to the processed rock sample when it is placed. Carry the rock sample from the cutting table to the sponge board on the ground. Then turn the rock sample over so that the well hole surface faces down to allow the water injected into the well hole during the slot cutting process to flow out. After the water flows out, lay waterproof cloth and buffer and anti-collision sponge boards around the rock sample and place it on the ground for preservation, waiting to be transported to the laboratory for the next experiment.

[0042] Step 102, conduct a physical similarity test of hydraulic fracturing on the prepared specimen.

[0043] The steps of the large-scale multi-stage hydraulic fracturing test are as follows: First, considering the in-situ stress conditions of high horizontal stress difference (horizontal stress difference > 10 MPa) in deep reservoirs, apply three-directional stresses synchronously on the surface of the specimen through the triaxial loading device equipped in the hydraulic fracturing system. The three-directional in-situ stresses adopted in this example are shown in Table 1. After the pressurization is completed, let the specimen stand for 30 minutes under the current boundary stress conditions, and then install acoustic emission probes on the surface of the specimen. The probes are directly connected to the specimen through a cementing agent to ensure efficient transmission of acoustic waves and reduce signal loss. Debug the acoustic emission equipment before the test to ensure that the signals of the acoustic emission equipment can be accurately collected. To avoid noise interference to the acoustic emission equipment during the test, it is necessary to exclude the influence of noise by setting a threshold value. In this test, the threshold value is set to 45 dB. Finally, inject fracturing fluid into the wellbore of the specimen. The fracturing fluid contains a dyeing agent that can be used to distinguish the hydraulic fractures generated by fracturing. Monitor the pumping pressure and the volume of the injected fracturing fluid in each fracturing stage through the flow monitoring system.

[0044] Step 103, analyze the macroscopic propagation characteristics of the hydraulic fractures inside the specimen after fracturing.

[0045] The hydraulic fracturing specimens after the physical simulation test were placed on an open flat ground. After standing for 24 hours to allow the fracturing fluid inside the specimen to dry, the specimens were struck with an engineering blasting hammer to cut out the main hydraulic fractures inside the specimens. The surface of the hydraulic fractures was dyed with a dye, which could be distinguished from the new fractures generated during the cutting process. A small engineering cone was used to carefully strike the area around the main hydraulic fractures to cut out the micro-fracture network around the main hydraulic fractures. The cutting results were recorded with a high-definition camera, and the extension morphology of the hydraulic fractures was extracted using Matlab software.

[0046] Step 104, analyzing the extension degree and type of hydraulic microcracks inside the sample after fracturing.

[0047] The AE-Win software was used to extract the acoustic emission signals released during the expansion of hydraulic fractures monitored by the acoustic emission monitoring equipment. The extent of hydraulic fracture expansion was determined by the number of acoustic emission events that exceeded the threshold value. The more acoustic emission events, the more intense the strain energy release during the initiation and expansion of the fractures, indicating that the hydraulic fractures expanded more intensely. In addition, the acoustic emission information monitored during rock failure—rise angle (RA) and average frequency (AF)—can be used to distinguish microfracture types. When the RA value is low and the AF value is high, it indicates that tensile failure leads to tensile fracture; conversely, if the RA value is high and the AF value is low, it indicates shear failure and shear fracture occurs. The acoustic emission information monitored during hydraulic fracturing is plotted in the RA-AF diagram. The percentage of AE counts above the specified dividing line represents the proportion of tensile fractures, and the percentage of AE counts below the dividing line represents shear fractures. Figure 2 The graphical process of identifying microcrack types using the AF-RA method is explained in detail.

[0048] Step 105, analyzing the correlation between the fluctuation characteristics of the test pumping curve and the expansion characteristics of the hydraulic fracture.

[0049] The Origin software is used to visualize the fluctuation characteristics of the pumping curve, and the main characteristics of the fluctuation of the pumping curve are extracted: the frequency and amplitude of the fluctuation. The real-time monitoring data of the fluctuation frequency and amplitude of the pumping curve are linked to the real-time expansion characteristics of the hydraulic fractures (expansion severity and fracture type) obtained by analyzing the acoustic emission monitoring data. The corresponding relationship between the expansion of the hydraulic fractures under the current reservoir conditions of the fracturing site and the degree of fluctuation of the pumping curve is given. At the same time, the final expansion form of the hydraulic fracture obtained by sectioning is used to verify and adjust the obtained conclusions. Finally, the fluctuation frequency and amplitude of the field pumping curve are compared with the experimental pumping curve, which can determine the expansion degree and fracture type of the hydraulic fractures in the reservoir.

[0050] Step 106, obtaining the corresponding relationship between the fluctuation degree of the pumping curve and the expansion of the hydraulic fracture.

[0051] By conducting hydraulic fracturing tests on on-site reservoir outcrop samples, the injection pressure curve was obtained, and the acoustic emission data during the entire loading process of the samples was observed and recorded.

[0052] Through a comprehensive analysis of the test results, it was found that the type of hydraulic fracture propagation is closely related to the fluctuations in the pump pressure curve. When tensile fractures control fracture propagation, the pump pressure curve is relatively smooth and the pump pressure fluctuations are small. The higher the proportion of tensile fractures, the fewer the fluctuations in the pump pressure curve. When the proportion of tensile fractures exceeds 90%, the pump pressure curve fluctuates only when the main hydraulic fracture propagates. On the contrary, the higher the proportion of shear fractures, the greater the frequency of pressure fluctuations in the pump pressure curve. This is consistent with the phenomenon that shear fractures promote the fusion of complex microcracks and tensile fractures into the main fracture. Therefore, the degree of fluctuation of the pump pressure curve can be used to evaluate the proportion of tensile fractures and shear fractures, providing a reference for on-site evaluation of the type and propagation state of hydraulic fractures. The specific test results are shown in Figures 3 - 7 .

[0053] In summary, the relationship between the fracture type and the pump pressure curve fluctuation is close: the higher the frequency of pump injection pressure fluctuations, the more complex the extension of hydraulic fractures in a single perforation cluster, the rougher the fracture surface, and the higher the proportion of hydraulic shear fractures; conversely, when the frequency of pump injection pressure fluctuations is lower, the extension of hydraulic fractures in a single perforation cluster is simpler, the fracture surface is smoother, and the proportion of tensile fractures is higher.

[0054] In summary, the embodiment of the present invention provides a method for monitoring hydraulic fractures based on the fluctuation frequency of the injection curve. First, by excavating and collecting reservoir outcrop rock samples at the fracturing site, and through a series of processing methods such as cutting, drilling, and slotting, they are made into hydraulic fracturing test samples; then, a physical simulation test of hydraulic fracturing is carried out to simulate the initiation and propagation behavior of hydraulic fractures during the on-site fracturing process; finally, through the test injection curve and the characteristics of hydraulic fracture propagation, the corresponding relationship between the hydraulic fracture propagation in the on-site reservoir and the degree of fluctuation of the injection curve is analyzed, providing support for determining the characteristics of hydraulic fracture propagation at the fracturing site. By using the on-site injection curve with the method of the present invention, the characteristics of hydraulic fracture propagation in the reservoir can be analyzed efficiently and economically, solving the problems of high cost and large environmental impact in fracture monitoring in previous hydraulic fracturing projects. Therefore, this method can strengthen the understanding of the characteristics of hydraulic fracture propagation and provide a reference for the relevant design and safety stability evaluation of unconventional oil and gas exploitation projects.

[0055] Those skilled in the art will readily think of other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the claims above.

[0056] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A hydraulic fracture monitoring method based on pumping curve fluctuation frequency, characterized in that: Here are the steps: Collect surface outcrop rock samples of unconventional oil and gas reservoirs at the fracturing site, cut and grind the collected surface outcrop rock samples into cubic specimens; determine the diameter and length of the wellbore, the layout of the perforation clusters, the layout of the fracturing sections, and the flow and viscosity of the fracturing fluid based on the hydraulic fracturing similarity criteria and field fracturing data; A wellbore is drilled in the center of the sample, and an annular slit is excavated on the inner wall of the wellbore to simulate a perforation cluster. One annular slit represents a perforation cluster. The wellbore is divided into a fracturing section and a sealing section, and the sealing section separates each fracturing section; multiple water injection pipes are set at the fracturing section, and the water injection pipes are respectively connected to the water pressure pump and the water pressure monitoring equipment to realize the independent pump pressure monitoring of multiple fracturing sections; the in-situ stress corresponding to the unconventional oil and gas reservoir is applied to the surface of the sample, and after the sample remains stable under the in-situ stress, the acoustic emission monitoring equipment is installed on the surface of the sample, and the acoustic emission probe is attached to the surface of the sample; finally, the fracturing fluid is continuously injected into the wellbore to simulate the fracturing process, and the dynamic change process of the pumping curve during the fracturing process of multiple fracturing sections is monitored at the same time; The samples after fracturing were cut to observe the macroscopic expansion of the hydraulic fractures inside the samples. The AF-RA method was used to process the acoustic emission monitoring data to determine the expansion degree and type of hydraulic micro-fractures. The fracture types were shear fractures and tensile fractures. Origin was used to visualize the fluctuation degree of the pumping curve and extract the dynamic change characteristics of the frequency and amplitude of the pumping curve. The fluctuation degree of the pumping curve at a cluster of perforations is proportional to the proportion of shear fractures in the process of hydraulic fracture expansion. The fluctuation degree of the pumping curve can reflect the macro- and micro-extension of hydraulic fractures in the current unconventional oil and gas reservoirs. Therefore, during the field fracturing process, the expansion degree and fracture type of the hydraulic fractures in the reservoir can be preliminarily judged by comparing the fluctuation degree of the field pumping curve monitored in real time with that of the test pumping curve.

2. The hydraulic fracture monitoring method according to claim 1, characterized in that: The perforation cluster layout includes perforation length, width, number and spacing, and the fracturing stage layout includes the number and spacing of fracturing stages.

3. The hydraulic fracture monitoring method according to claim 1, characterized in that: Each fracturing stage contains multiple clusters of perforations, and epoxy resin is used to form a sealing section to prevent the communication of fracturing fluid between the fracturing stages.

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