A physical simulation experiment device and method for perforation-impingement-fracturing combined operation

Abstract

The application discloses a physical simulation experiment device and method for perforation-impingement-fracturing combined operation, and the physical simulation experiment device comprises the following: an experimental rock sample; a stress loading system for loading three-directional compressive stress on the experimental rock sample to simulate the stress of a target reservoir; a perforation system integrated with a real industrial perforating gun, a plurality of experimental rock samples are connected through a casing, the perforating gun is inserted into a preset fracturing section position of the experimental rock sample through the casing, the perforating gun is triggered, and a real perforation explosion fracturing process is simulated; a fracturing system comprising a full-scale fracturing pump truck group and an electromagnetic pulse generator, the full-scale fracturing pump truck group is communicated with the casing and is used for simulating an industrial hydraulic fracturing process, the electromagnetic pulse generator supports synchronous operation with the hydraulic fracturing process and is used for emitting electromagnetic pulses to the experimental rock sample, secondary cracks are activated through directional energy release, and a crack impingement process is simulated; and a monitoring system for monitoring experimental data of the physical simulation experiment process of the perforation-impingement-fracturing combined operation.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, specifically to a physical simulation experimental device and method for perforation-impact-fracturing combined operation. Background Technology

[0002] In oil and gas field development, perforation-fracturing combined technology is a key means to improve reservoir stimulation efficiency, but its practical application is limited by the shortcomings of traditional experimental methods. Traditional fracturing physical simulation experiments mostly use small-sized rock samples, which are difficult to accurately reflect the in-situ stress distribution, inter-stage stress differences, and dynamic effects of perforation in the reservoir. Small-sized rock samples cannot simulate the large-scale reservoir stress field distribution, leading to distortion of fracture propagation patterns; existing devices lack the integration capability of real perforation guns and cannot reproduce the impact of perforation explosion shock waves on fracture initiation; monitoring technologies are limited and cannot capture the complex fracture propagation behavior and fluid migration paths of multi-stage fracturing. These problems result in significant deviations between experimental data and field applications, necessitating the development of a physical simulation device based on large-sized rock samples, integrating real perforation guns, and supporting full-scale fracturing and electromagnetic pulse experiments, combined with microseismic and fiber optic monitoring technologies, to accurately evaluate the adaptability of the perforation-impact-fracturing combined process.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a physical simulation experimental device and method for combined perforation-impact-fracturing, resolving the stress field distortion issue caused by insufficient scale in traditional small-sized rock sample experiments. This provides industrial-grade experimental basis for optimizing perforation parameters, fracturing fluid formulation, and inter-stage stress difference control, ultimately achieving efficient adaptation of the combined perforation-impact-fracturing process and accurate prediction of reservoir stimulation effects. Specifically, the following technical solution is adopted:

[0005] A physical simulation experimental device for perforation-impact-fracturing combined operation includes:

[0006] Experimental rock samples, wherein the experimental rock samples are large physical model rock samples with a size of one meter or more;

[0007] The stress loading system, equipped with a multi-axis hydraulic servo device, is used to apply triaxial compressive stress to the experimental rock sample to simulate the target reservoir stress.

[0008] The perforation system integrates a real industrial-grade perforation gun. Multiple experimental rock samples are connected by a casing. The perforation gun extends from the casing into the preset fracturing section of the experimental rock sample, triggering the perforation gun and simulating the real perforation explosion fracturing process.

[0009] A fracturing system, comprising a full-scale fracturing pump truck group and an electromagnetic pulse generator, the full-scale fracturing pump truck group being in communication with the casing for simulating an industrial hydraulic fracturing process, and the electromagnetic pulse generator supporting synchronous operation with the hydraulic fracturing process for emitting electromagnetic pulses to the experimental rock sample to activate secondary cracks through directional energy release and simulate a crack impact process.

[0010] A monitoring system for monitoring experimental data of a physical simulation experiment process of a perforation-impingement-fracturing combined operation.

[0011] The monitoring system comprises a high-precision pressure sensor, a flow meter and a high-speed camera for recording auxiliary data of perforation dynamics and crack expansion details to form a macroscopic crack-microscopic fluid data complement.

[0012] As an optional embodiment of the present application, the monitoring system comprises:

[0013] An arrayed microseismic sensor is arranged on the experimental rock sample to capture crack expansion signals of the experimental rock sample in real time during the physical simulation experiment process and to invert a three-dimensional crack geometry.

[0014] A distributed optical fiber is embedded on the surface and inside of the experimental rock sample to collect a temperature gradient field and a strain distribution in real time and analyze a fluid migration path and a proppant filling efficiency.

[0015] The present application also provides an experimental method of the physical simulation experiment device of the perforation-impingement-fracturing combined operation, comprising:

[0016] The plurality of experimental rock samples are connected through a casing.

[0017] A three-way compressive stress is loaded to the experimental rock sample by controlling the stress loading system to simulate a target reservoir stress.

[0018] The perforation system is triggered to simulate a real perforation explosion fracturing process.

[0019] The full-scale fracturing pump truck group of the fracturing system is controlled to inject a fracturing fluid containing proppants into the inside of the experimental rock sample through the casing to simulate an industrial hydraulic fracturing process.

[0020] The electromagnetic pulse generator of the fracturing system is controlled to operate synchronously with the hydraulic fracturing process to emit electromagnetic pulses to the experimental rock sample to activate secondary cracks through directional energy release and simulate a crack impact process.

[0021] The control of the perforation system to trigger to simulate a real perforation explosion fracturing process comprises:

[0022] The perforation gun of the perforation system is fixed and connected to a trigger system at a preset perforation position on the surface of the experimental rock sample.

[0023] The trigger system controls the perforating gun to start, synchronously controls a high-speed camera to shoot the shape change of the perforating hole during the perforating explosion fracturing, and acquires pressure data of a high-precision pressure sensor during the perforating explosion fracturing to draw a pressure sudden change curve.

[0024] As an optional embodiment of the present application, in the experimental method of the present application, after simulating the real perforating explosion fracturing process, the stress difference between the two adjacent experimental rock samples is adjusted by controlling the multi-axis hydraulic servo device of the stress loading system, so that the fracturing fluid preferentially enters the low stress section during the hydraulic fracturing process, and the proppant is filled to form a continuous control chain of "perforation directional initiation → stress guided expansion".

[0025] As an optional embodiment of the present application, the experimental method of the present application comprises:

[0026] When it is monitored that the crack extends to the boundary of the experimental rock sample, or the pump injection pressure of the full-scale fracturing pump truck group decreases to a preset percentage of the initial pump injection pressure value, the experiment is terminated.

[0027] As an optional embodiment of the present application, the experimental method of the present application comprises data analysis, and the data analysis comprises:

[0028] The three-dimensional crack geometry model is inverted by capturing the crack expansion signal of the experimental rock sample in the physical simulation experiment in real time through the array microseismic sensor;

[0029] Based on the three-dimensional crack geometry model, the main crack and the secondary crack distribution are labeled, and the main crack turning angle and the secondary crack density key parameters are identified.

[0030] As an optional embodiment of the present application, in the experimental method of the present application, the data analysis comprises:

[0031] The temperature gradient field and the strain distribution are collected in real time through the distributed optical fiber;

[0032] The fluid swept range and the proppant filling rate are verified in combination with CT scanning.

[0033] As an optional embodiment of the present application, the experimental method of the present application comprises process optimization, and the process optimization comprises:

[0034] Perforation parameter optimization: when the stress difference between the sections is greater than a preset pressure difference threshold Pt, the perforation density is increased to N holes per meter, N is a positive integer, to enhance the crack initiation uniformity, and the values of the preset pressure difference threshold Pt and N are obtained based on the data analysis of the simulation experiment;

[0035] Fracturing fluid adaptation: high-viscosity fracturing fluid (≥80 mPa•s) is used in the dense reservoir to improve the longitudinal expansion capability.

[0036] As an optional embodiment of the present application, in the experimental method of the present application, the experimental rock sample adopts a large-size natural or artificial rock sample with a size of 2m*2m*1m, a permeability range of 0.1-1000mD, and a porosity of 5%-25%, so as to simulate the reservoir heterogeneity and fracture development characteristics.

[0037] Compared with the prior art, the present application has the following beneficial effects:

[0038] The physical simulation experiment device for perforation-impact-fracturing combined operation of the present application simulates the in-situ stress field and inter-section stress difference of the reservoir by using a large-size experimental rock sample, breaks through the limitation of traditional scale, and solves the problem of stress field distortion caused by insufficient scale in traditional small-size rock sample experiments; the device restores the influence of the perforation dynamic process on the crack initiation position and perforation shape by integrating a real perforating gun to dynamically trigger a perforation explosion shock wave; the device simulates the combined operation effect of hydraulic fracturing and electromagnetic pulse cooperative reconstruction of the fracture network by synchronously operating a full-scale fracturing pump truck group and an electromagnetic pulse generator; the device uses a monitoring system to capture the crack propagation path, temperature field and strain field distribution in real time, calculates the crack conductivity and fracturing fluid efficiency through high-precision pressure sensors and electromagnetic flowmeters, forms a multi-dimensional data fusion analysis platform, provides an industrial-level experimental basis for optimizing perforation parameters, fracturing fluid formula and inter-section stress difference control, and finally realizes efficient adaptation of the perforation-impact-fracturing combined operation process and accurate prediction of the reservoir reconstruction effect. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The structural principle diagram of the physical simulation experiment device for perforation-impact-fracturing combined operation of the embodiment of the present application;

[0040] Figure 2 The flowchart of the experimental method of the physical simulation experiment device for perforation-impact-fracturing combined operation of the embodiment of the present application.

[0041] Label explanation in the drawings: 100-experimental rock sample, 101-perforation, 200-casing, 300-perforating gun, 400-distributed optical fiber, 500-array type microseismic sensor, 600-high-precision pressure sensor, 700-full-scale fracturing pump truck group, 800-electromagnetic pulse generator, 900-perforation operation system, and 1000-monitoring system. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments.

[0043] Therefore, the following detailed description of the embodiments of the application is not intended to limit the scope of the application as claimed, but merely represents some embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0044] It should be noted that the embodiments in the application and the features and technical solutions in the embodiments can be combined with each other without conflict.

[0045] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0046] In the description of the application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", etc. are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0047] Referring to Figure 1 The physical simulation experiment device for perforation-impingement-fracturing combined operation of the embodiment shown comprises:

[0048] The experimental rock sample 100 is a large-scale physical model rock sample with a size specification of more than one meter;

[0049] The stress loading system is configured with a multi-axis hydraulic servo device for loading three-directional compressive stress on the experimental rock sample 100 to simulate the stress of the target reservoir;

[0050] The perforation system integrates a real industrial perforating gun 300, and a plurality of experimental rock samples 100 are connected through a casing 200. The perforating gun 300 is inserted into the preset fracturing section position of the experimental rock sample 100 through the casing 200, the perforating gun 300 is triggered, and the real perforation explosion fracturing process is simulated;

[0051] A fracturing system includes a full-scale fracturing pump truck group 700 in communication with the casing 200 for simulating an industrial hydraulic fracturing process, and an electromagnetic pulse generator 800 supporting synchronous operation with the hydraulic fracturing process for emitting electromagnetic pulses to the experimental rock sample 100 to activate secondary cracks through directional energy release to simulate a crack impact process.

[0052] A monitoring system 1000 monitors experimental data of a physical simulation experiment process of the perforation-impingement-fracturing combined operation.

[0053] The perforation-impingement-fracturing combined operation physical simulation experiment device of the embodiment simulates in-situ stress field and inter-segment stress difference of a reservoir through a large-size experimental rock sample 100, breaks through the limitation of traditional scale, and solves the problem of stress field distortion caused by insufficient scale in traditional small-size rock sample experiments; the dynamic perforation explosion shock wave is triggered by integrating a real perforating gun 300 to restore the influence of the perforation dynamic process on the crack initiation position and the perforation shape; the synchronous operation of the full-scale fracturing pump truck group 700 and the electromagnetic pulse generator 800 is combined to simulate the combined operation effect of the hydraulic fracturing and the electromagnetic pulse in the reconstruction of the crack network; the monitoring system is used to capture the crack propagation path, temperature field and strain field distribution in real time, the high-precision pressure sensor and the electromagnetic flowmeter are used to calculate the crack conductivity and the fracturing fluid efficiency, and a multi-dimensional data fusion analysis platform is formed to provide an industrial experiment basis for optimizing the perforation parameters, the fracturing fluid formula and the inter-segment stress difference control, and finally realize the efficient adaptation of the perforation-impingement-fracturing combined operation process and the accurate prediction of the reservoir reconstruction effect.

[0054] Further, the monitoring system 1000 described in the embodiment includes:

[0055] The arrayed microseismic sensor 500 is arranged on the experimental rock sample 100 to capture the experimental rock sample crack propagation signal in real time during the physical simulation experiment process, and to invert the three-dimensional crack geometry;

[0056] The distributed optical fiber 400 is embedded in the surface and interior of the experimental rock sample 100 to collect the temperature gradient field and strain distribution in real time, analyze the fluid migration path and the proppant filling efficiency, and form the “macroscopic crack-microscopic fluid” data complementation.

[0057] The auxiliary sensors include a high-precision pressure sensor 600, a flowmeter and a high-speed camera to record auxiliary data of the perforation dynamics and crack propagation details.

[0058] The embodiment builds a full-process combined operation system of “perforation-induced crack initiation-stress-regulated propagation-electromagnetic pulse permeability enhancement-data closed-loop optimization” through the microseismic-optical fiber multi-dimensional monitoring fusion technology, and provides industrial-level parameter simulation capability and high-precision multi-dimensional data support for optimizing the perforation-impingement-fracturing combined operation process.

[0059] The physical simulation experiment device for the perforation-impingement-fracturing combined operation of the embodiment comprises a perforation operation system 900, which is used to control the perforation gun 300 of the perforation system to trigger at the preset fracturing section position of the experimental rock sample 100, form a perforation 101 in the experimental rock sample 100, and record the hole diameter, rupture pressure and impingement wave propagation speed of the perforation 101.

[0060] The perforation operation system 900 comprises the perforation gun, the explosion-proof isolation nipple, the tension nipple and the positioning nipple which are sequentially connected in the same housing, and the connecting cable and the cable core connector. One end of the connecting cable is connected with the explosion-proof isolation nipple, the tension nipple and the positioning nipple respectively, and the other end is connected with the cable core connector. The cable core connector is used to realize the winding and unwinding of the connecting cable. The perforation operation system 900 further comprises a touch screen and a control panel which are used to operate and control the cable core connector. Referring to Figure 2 The embodiment simultaneously provides an experimental method of the physical simulation experiment device for the perforation-impingement-fracturing combined operation, which comprises the following steps:

[0061] The plurality of experimental rock samples are connected through the casing;

[0062] The stress loading system is controlled to load three-directional compressive stress on the experimental rock sample to simulate the stress of the target reservoir;

[0063] The perforation system is controlled to trigger to simulate the real perforation explosion fracturing process;

[0064] The full-scale fracturing pump truck group of the fracturing system is controlled to inject the fracturing fluid containing the proppant into the interior of the experimental rock sample through the casing to simulate the industrial-grade hydraulic fracturing process;

[0065] The electromagnetic pulse generator of the fracturing system is controlled to work synchronously with the hydraulic fracturing process to emit electromagnetic pulses to the experimental rock sample to release directional energy and activate the secondary cracks to simulate the crack impingement process.

[0066] The experimental method of the physical simulation experiment device for the perforation-impingement-fracturing combined operation of the embodiment simulates the in-situ stress field and the inter-section stress difference of the reservoir through the large-size experimental rock sample, integrates the dynamic triggering of the real perforation gun to form the perforation explosion impingement wave, synchronously couples the full-scale hydraulic fracturing and the electromagnetic pulse energy release, and constructs the full-process combined operation system of "perforation-induced crack initiation-stress-regulated extension-electromagnetic pulse imbibition-data closed-loop optimization" through the multi-dimensional monitoring fusion technology, thereby providing the industrial-grade parameter simulation capability and high-precision multi-dimensional data support for optimizing the perforation-impingement-fracturing combined operation process.

[0067] In the experimental method of the embodiment, the step of controlling the perforation system to trigger to simulate the real perforation explosion fracturing process comprises the following steps:

[0068] Pre-set perforation position on the surface of the experimental rock sample, fix the perforating gun of the perforating system and connect the trigger system;

[0069] Control the trigger system to start the perforating gun, synchronously control the high-speed camera to shoot the shape change of the perforation hole during the perforation explosion induced cracking process, and obtain the pressure data of the high-precision pressure sensor during the perforation explosion induced cracking process to draw the pressure transient curve.

[0070] In the experimental method of the embodiment, after simulating the real perforation explosion induced cracking process, the inter-segment stress difference between the adjacent two experimental rock samples is adjusted by controlling the multi-axis hydraulic servo device of the stress loading system, so that the fracturing fluid preferentially enters the low stress segment during hydraulic fracturing, and combined with proppant filling, a continuous control chain of "perforation directional initiation → stress guided propagation" is formed.

[0071] The experimental method of the embodiment includes: when it is monitored that the crack extends to the boundary of the experimental rock sample, or the pump injection pressure of the full-scale fracturing pump truck group drops to a preset percentage of the initial pump injection pressure value, the experiment is terminated.

[0072] The experimental method of the embodiment includes data analysis, which includes: capturing the crack propagation signal of the experimental rock sample in the physical simulation experiment in real time by the array microseismic sensor, and inverting the three-dimensional crack geometry model; based on the three-dimensional crack geometry model, labeling the main crack and the secondary crack distribution, and identifying the main crack turning angle and the secondary crack density key parameters.

[0073] The data analysis of the embodiment includes: real-time acquisition of temperature gradient field and strain distribution by the distributed optical fiber; and verification of fluid sweep range and proppant filling rate by CT scanning.

[0074] The experimental method of the embodiment includes process optimization, which includes:

[0075] Perforation parameter optimization: when the inter-segment stress difference is greater than a preset pressure difference threshold Pt, the perforation density is increased to N holes per meter, N is a positive integer, to enhance the crack initiation uniformity, and the values of the preset pressure difference threshold Pt and N are obtained based on the data analysis of the simulation experiment;

[0076] Fracturing fluid adaptation: high viscosity fracturing fluid (≥80 mPa•s) is used in the dense reservoir to improve the longitudinal propagation ability.

[0077] In the experimental method of the embodiment, the experimental rock sample uses a large-size natural or artificial rock sample with a size of 2m×2m×1m, a permeability range of 0.1~1000mD, and a porosity of 5%~25%, to simulate the reservoir heterogeneity and fracture development characteristics.

[0078] As a specific embodiment of the physical simulation experiment device and experiment method for perforation-impingement-fracturing combined operation of the present application, it specifically comprises:

[0079] 1. Experiment device composition

[0080] Experiment rock sample

[0081] A large-size natural or artificial rock sample is adopted, the size is 2m*2m*1m, the permeability range is 0.1-1000mD, and the porosity is 5%-25%, which breaks through the stress field distortion limitation of traditional small-size rock sample, and accurately simulates the reservoir heterogeneity and fracture development characteristics.

[0082] Stress loading system

[0083] A multi-axis hydraulic servo device is configured, the vertical stress is 0-50MPa, the maximum / minimal stress difference is 0-10MPa, the accurate dynamic regulation of the stress difference between adjacent fracturing segments is supported, and the stress difference caused by the reservoir heterogeneity is reproduced.

[0084] Perforation system

[0085] A real perforating gun (aperture 6-12mm, hole density 16-24 holes / meter) is integrated, the perforating bullet charge is 5-15g, the perforation operation is triggered through a high-voltage cable, and the induction effect of the explosion shock wave on the crack initiation is reproduced.

[0086] Intelligent timing controller: based on the dynamic propagation characteristics (speed, peak pressure) of the perforation shock wave, the optimal starting delay (10-50ms) of the hydraulic fracturing and electromagnetic pulse is automatically calculated, and it is ensured that the energy is superimposed at the crack tip.

[0087] Fracturing system

[0088] Full-scale fracturing pump truck set: displacement 0.5-10m³ / min, pressure 0-70MPa, simulating industrial-grade hydraulic fracturing.

[0089] Electromagnetic pulse generator: pulse frequency 1-50Hz, single pulse energy 0.1-5kJ, supporting synchronous operation with hydraulic fracturing, and having energy directional focusing function.

[0090] Monitoring system

[0091] Microseismic monitoring: array type microseismic sensor (frequency band 50Hz-2kHz, positioning accuracy ±0.1m) is arranged on the outer wall of the rock sample.

[0092] Optical fiber monitoring: distributed optical fiber (DAS / DTS) is embedded in the surface and internal pre-drilled channel of the rock sample, and temperature, strain and acoustic signals are collected in real time;

[0093] Edge computing unit: deployed in the experimental device, synchronously processing microseismic positioning, optical fiber temperature gradient (resolution 0.1 ℃ / m) and pressure data, and generating a crack propagation prediction model within 5 seconds.

[0094] Auxiliary sensors: high-precision pressure sensor (±0.1% FS), electromagnetic flowmeter (±1% accuracy), high-speed camera (2000 fps) recording perforation dynamics and crack morphology.

[0095] 2. Experimental method flow

[0096] Experimental rock sample pretreatment: clean and dry the experimental rock sample, load vertical stress 30 MPa, horizontal maximum stress 25 MPa, and horizontal minimum stress 20 MPa, and stabilize for 30 minutes.

[0097] Experimental parameter setting

[0098] In-situ stress: vertical stress 30 MPa, horizontal maximum stress 25 MPa, and horizontal minimum stress 20 MPa.

[0099] Intersegment stress difference: adjacent fracture segment horizontal stress difference 5 MPa.

[0100] Perforation parameters: hole density 20 holes / meter, hole diameter 10 mm, and perforating charge 8 g.

[0101] Fracturing parameters: displacement 5 m³ / min, fracturing fluid viscosity 50 mPa•s, and proppant concentration 15%.

[0102] Electromagnetic pulse parameters: frequency 10 Hz, single pulse energy 2 kJ.

[0103] Perforation operation

[0104] Trigger the perforating gun at the preset fracturing segment position, record the hole diameter, breakdown pressure, and shock wave propagation speed;

[0105] Synchronously trigger the electromagnetic pulse guide device through the intelligent timing controller to ensure that the energy is released along the perforation axis.

[0106] Intersegment stress difference dynamic regulation

[0107] Based on the microseismic data (crack diversion angle, branch density) and optical fiber strain distribution of the previous segment fracturing, the horizontal stress difference of the adjacent fracturing segment is adjusted in real time (such as ±2 MPa), guiding the crack diversion to the unmodified area.

[0108] Fracturing experiment

[0109] Hydraulic fracturing: inject fracturing fluid containing proppant (viscosity 30~100 mPa•s) at an industrial displacement (such as 5 m³ / min), and synchronously collect pressure and flow data.

[0110] Electromagnetic pulse synergy: Apply electromagnetic pulses (e.g., frequency 10 Hz, energy 2 kJ) during fracturing, combined with the resonance effect of energy coupling rings, to promote fracture branch expansion.

[0111] Dynamic parameter adjustment: If the real-time flow conductivity decreases by more than 15%, immediately increase the electromagnetic pulse energy to 3 kJ to activate secondary fractures.

[0112] Data synchronous acquisition and feedback

[0113] Microseismic data inversion of fracture three-dimensional geometry (length, height, azimuth);

[0114] Fiber data plot temperature gradient field and strain distribution, generate flow conductivity thermal map;

[0115] Edge computing unit real-time output fracture prediction model, dynamic optimization of fracturing fluid displacement, pulse frequency and inter-stage stress difference.

[0116] Experiment termination: Stop injection when the fracture extends to the boundary of the experimental rock sample or the pump pressure drops to 70% of the initial value.

[0117] 3. Core innovation

[0118] Time-energy synergy optimization:

[0119] Through intelligent timing controller, realize three-dimensional superposition of perforation shock wave, electromagnetic pulse and hydraulic fracturing energy, fracture branch density increases by more than 50%.

[0120] Example: When the perforation shock wave frequency is 5 kHz, the electromagnetic pulse frequency is adjusted to 10 kHz, and the secondary fracture density increases from 3 / m to 8 / m.

[0121] Cross-segment data closed-loop feedback:

[0122] Based on the microseismic events and fiber strain distribution of the previous segment data, dynamically adjust the stress difference and perforation parameters of the adjacent segment, and reduce the inter-stage reconstruction overlap rate to below 10%.

[0123] Perforation aperture data (e.g., 10±0.5 mm) is directly related to proppant particle size selection (2~4 mm), avoiding hole plugging.

[0124] Multi-dimensional intelligent fusion platform:

[0125] Build a "fracture intelligent body" digital twin model, integrate microseismic, fiber, and pressure data, and optimize fracturing parameters in real time through reinforcement learning algorithm.

[0126] Example: When the fracture expansion rate is lower than the threshold, automatically trigger the high-frequency mode (20 Hz) of electromagnetic pulse and increase the fracturing fluid viscosity to 80 mPa•s.

[0127] Edge computing real-time decision:

[0128] Crack propagation prediction and parameter adjustment completed within 5 seconds, fracturing fluid efficiency increased by 25%, and proppant coverage rate > 90%.

[0129] 4. Application scenarios

[0130] Fracturing design for unconventional reservoirs: Through dynamic inter-stage stress difference regulation and energy coordination, optimize perforation density and fracturing fluid formulation for shale and tight sandstone reservoirs.

[0131] Electromagnetic pulse technology verification: Evaluate the effect of harmonic resonance and directional energy release on fracture network modification.

[0132] Intelligent fracturing monitoring: Use edge computing and digital twin technology to improve the interpretation accuracy of on-site monitoring data and process response speed. Embodiment

[0133] The experimental method of the physical simulation experiment device for perforation-impingement-fracturing combined operation in this embodiment realizes multi-stage fracturing experiment in high-temperature and high-pressure reservoirs.

[0134] Experimental conditions

[0135] Experimental rock sample parameters: Size: 2m x 2m x 1m (natural sandstone), permeability 50mD, porosity 12%, simulate shale reservoir heterogeneity.

[0136] Fracture development: Pre-made artificial fractures (width 0.5~2mm, length 1.5m), simulate natural fracture network.

[0137] Stress setting: Vertical stress 35MPa, horizontal maximum stress 30MPa, horizontal minimum stress 25MPa.

[0138] Adjacent fracturing stage stress difference: Stage 1 (30MPa) and stage 2 (25MPa), stress difference 5MPa.

[0139] Perforation parameters: Perforation density 20 holes / meter, hole diameter 10mm, perforating bullet charge 8g, use shaped charge perforating bullet (model SC-100).

[0140] Fracturing parameters: Fracturing fluid: crosslinked guar gum system, viscosity 50mPa•s, proppant (40 / 70 mesh ceramic) concentration 15%.

[0141] Displacement 5m³ / min, total injection volume 5000L, simulate industrial-scale fracturing scale.

[0142] Electromagnetic pulse parameters: Frequency 10Hz, single pulse energy 2kJ, pulse interval 5 seconds.

[0143] Experimental procedure

[0144] Perforation operation: Perforate the preset perforation locations (interval 0.5 m) in Section 1 and Section 2 with real perforating guns (bore diameter 10 mm).

[0145] High-voltage cable triggers perforation, and a high-speed camera (2000 fps) records the perforation morphology, and the initial breakdown pressure is measured to be 28 MPa.

[0146] Fracturing injection: Start the fracturing pump to inject fracturing fluid at a displacement of 5 m³ / min, while applying electromagnetic pulses (pulse energy 2 kJ).

[0147] Real-time monitoring of the pressure-flow curve shows that the fracturing fluid breakthrough pressure is 32 MPa, and the peak pressure is 38 MPa.

[0148] Data acquisition: Microseismic monitoring: The array sensor captures 12 microseismic events, and the inversion shows that the total length of the cracks is 15 m, the azimuth angle of the main crack is 45°, and the secondary crack density is 3 / m.

[0149] Optical fiber monitoring: DTS data shows that the temperature gradient is > 5°C / m, indicating a proppant packing area (coverage > 85%).

[0150] Auxiliary data: The fracturing fluid efficiency is calculated to be 78% (proppant packing volume / injected volume).

[0151] Experimental results and optimization

[0152] Fracture propagation analysis: The stress difference between sections causes the crack to turn, and the proppant preferentially enters the low-stress section.

[0153] Optimization suggestion: When the stress difference between sections is > 5 MPa, the perforation density is increased to 24 holes / m, and the uniform initiation of the crack is enhanced.

[0154] The viscosity of the fracturing fluid is increased to 80 mPa•s to inhibit excessive turning of the crack. Embodiment

[0155] The experimental method of the physical simulation experiment device for perforation-impingement-fracturing combined operation in this embodiment realizes electromagnetic pulse coordinated fracturing experiments in low-permeability reservoirs.

[0156] Experimental conditions

[0157] Experimental rock sample parameters: Size: 2m x 2m x 1m core, permeability 10 mD, porosity 8%, simulating a dense sandstone reservoir.

[0158] Fracture simulation: No pre-made cracks, simulating a naturally occurring low-permeability matrix.

[0159] Stress setup: vertical stress 30 MPa, horizontal maximum stress 25 MPa, horizontal minimum stress 20 MPa.

[0160] Single-stage fracturing, no inter-stage stress difference.

[0161] Perforation parameters: perforation density 16 holes / m, hole diameter 8 mm, perforating charge 6 g (type SC-80).

[0162] Fracturing parameters: fracturing fluid: slick water system, viscosity 3 mPa•s, nano proppant (100-200 nm silica) concentration 1%.

[0163] Displacement 3 m³ / min, total injection volume 3000 L.

[0164] Electromagnetic pulse parameters: frequency 20 Hz, single pulse energy 3 kJ, pulse interval 3 seconds.

[0165] Experimental steps

[0166] Perforation operation: after single-stage perforation, high-speed camera shows that the hole diameter is 8.2 mm, and the initial breakdown pressure is 25 MPa.

[0167] Fracturing injection: start the fracturing pump to inject slick water, and synchronously apply high-frequency electromagnetic pulses (pulse energy 3 kJ).

[0168] Real-time pressure curve shows that the fracture initiation pressure is 27 MPa, and the fracturing fluid efficiency is increased to 65%.

[0169] Data acquisition: microseismic monitoring: microseismic event density reaches 25 / m, fracture network complexity increases by 40%, and the main fracture length is 8 m.

[0170] Optical fiber monitoring: strain data show that nano proppant enters micron-sized pores (coverage rate > 90%).

[0171] CT scanning: three-dimensional reconstruction shows that the fracture branch density is > 5 / cm².

[0172] Experimental results and optimization

[0173] Electromagnetic pulse effect: high-frequency pulses activate micro-fractures, and nano proppant effectively fills micro-pores.

[0174] Optimization suggestion: for low-permeability reservoirs, the electromagnetic pulse energy is recommended to be ≥ 3 kJ, and the pulse frequency is recommended to be ≥ 20 Hz.

[0175] The slick water system is suitable for nano proppant, and the optimal concentration is 1%-2%.

[0176] Through the perfection of the above-mentioned embodiments, the present embodiment clearly shows the experimental details and optimization path in high temperature and high pressure and low permeability reservoirs, and provides high credibility data support for field technology by combining with industrial grade parameters and multi-dimensional monitoring technology.

[0177] The above embodiments are only used to illustrate the technical solutions described in the present application and not to limit the present application. Although the present application has been described in detail with reference to the above-mentioned embodiments, the present application is not limited to the above-mentioned specific embodiments. Therefore, any modification or equivalent replacement of the present application; and all technical solutions and improvements without departing from the spirit and scope of the application are all included in the scope of the claims of the present application.

Claims

1. An experimental method for a physical simulation experimental apparatus for perforation-impact-fracturing combined operation, characterized in that, The physical simulation experimental setup includes: Experimental rock samples, wherein the experimental rock samples are large physical model rock samples with a size of one meter or more; The stress loading system is equipped with a multi-axis hydraulic servo device to apply triaxial compressive stress to the experimental rock sample to simulate the target reservoir stress. The perforation system integrates a real industrial-grade perforation gun. Multiple experimental rock samples are connected by a casing. The perforation gun extends from the casing into the preset fracturing section of the experimental rock sample, triggering the perforation gun and simulating the real perforation explosion fracturing process. The fracturing system includes a full-scale fracturing pump truck unit and an electromagnetic pulse generator. The full-scale fracturing pump truck unit is connected to the casing and is used to simulate the industrial-grade hydraulic fracturing process. The electromagnetic pulse generator supports synchronous operation with the hydraulic fracturing process and is used to emit electromagnetic pulses to the experimental rock sample to activate secondary fractures through directional energy release and simulate the fracture impact process. Intelligent timing controller: Based on the dynamic propagation characteristics of perforation shock waves, it automatically calculates the optimal start-up delay between hydraulic fracturing and electromagnetic pulse to ensure that energy is superimposed at the fracture tip; The monitoring system monitors experimental data from the physical simulation process of perforation-impact-fracturing. The monitoring system includes a high-precision pressure sensor, a flow meter, and a high-speed camera to record auxiliary data on perforation dynamics and fracture propagation details, forming a complementary "macro-fracture-micro fluid" data structure. The experimental methods include: Multiple experimental rock samples are connected by a sleeve; The target reservoir stress is simulated by applying triaxial compressive stress to the experimental rock sample through the stress loading system. The perforation system is controlled to trigger, simulating the real perforation explosion and fracturing process. The full-scale fracturing pump truck unit controlling the fracturing system injects proppant-containing fracturing fluid into the experimental rock sample through the casing to simulate the industrial-scale hydraulic fracturing process. The electromagnetic pulse generator controlling the fracturing system operates synchronously with the hydraulic fracturing process, emitting electromagnetic pulses to the experimental rock sample to release energy in a directional manner and activate secondary fractures, simulating the fracture impact process. After simulating the real perforation explosion fracturing process, the stress difference between two adjacent experimental rock samples is adjusted by the multi-axis hydraulic servo device of the stress loading system, so that the fracturing fluid preferentially enters the low-stress section during the hydraulic fracturing process. Combined with proppant filling, a continuous control chain of "perforation directional fracturing initiation → stress-guided propagation" is formed. The control of the perforation system to trigger, simulating the real perforation explosion-induced fracturing process, includes: Pre-set perforation positions on the surface of the experimental rock sample, fix the perforation gun of the perforation system and connect it to the triggering system; The control triggering system starts the perforation gun, and simultaneously controls the high-speed camera to capture the changes in the perforation orifice morphology during the perforation explosion and fracturing process, and acquires the pressure data from the high-precision pressure sensor during the perforation explosion and fracturing process, and plots the pressure change curve. The data analysis includes: The array of microseismic sensors captures the crack propagation signal of experimental rock samples in real time during the physical simulation experiment, and inverts the three-dimensional crack geometry model. Based on the three-dimensional crack geometry model, the distribution of primary and secondary cracks is marked, and key parameters such as the turning angle of primary cracks and the density of secondary cracks are identified. Temperature gradient field and strain distribution are acquired in real time using distributed optical fibers; The fluid sweep range and proppant filling rate were verified by combining CT scans.

2. The experimental method according to claim 1, characterized in that, The monitoring system includes: An array of microseismic sensors is installed on the experimental rock sample to capture the crack propagation signal of the experimental rock sample in real time during the physical simulation experiment and to invert the three-dimensional crack geometry. Distributed optical fibers are embedded in the surface and interior of the experimental rock sample to collect temperature gradient fields and strain distributions in real time, and to analyze fluid migration paths and proppant filling efficiency.

3. The experimental method according to claim 1, characterized in that, include: The experiment is terminated when the crack is detected to extend to the boundary of the experimental rock sample, or when the pumping pressure of the full-scale fracturing pump unit drops to a preset percentage of the initial pumping pressure value.

4. The experimental method according to claim 1, characterized in that, This includes process optimization, which includes: Perforation parameter optimization: When the inter-segment stress difference is greater than the preset pressure difference threshold Pt, the perforation density is increased to N holes / meter, where N is a positive integer, to enhance the uniformity of crack initiation. The values ​​of the preset pressure difference threshold Pt and N are obtained based on data analysis from simulation experiments. Fracturing fluid compatibility: High-viscosity fracturing fluid (≥80 mPa•s) is used in tight reservoirs to enhance vertical propagation capability.

5. The experimental method according to claim 1, characterized in that, The experimental rock samples were large-sized natural or artificial rock samples, with dimensions of 2m×2m×1m, permeability ranging from 0.1 to 1000mD, and porosity from 5% to 25%, simulating reservoir heterogeneity and fracture development characteristics.

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