Stress interference monitoring experiment method and stress interference monitoring experiment device

Abstract

This application provides a stress interference monitoring experimental method and apparatus. By designing a split-type pressure plate at the outlet of the core chamber for multi-well true triaxial hydraulic fracturing, the requirements of multi-well true triaxial hydraulic fracturing experiments are met. The split structure of the metal slider and rectangular groove can be freely adjusted and positioned according to the wellbore layout, solving the problem of fixed wellbore position in traditional integral pressure plates. Furthermore, high-strength sealing of the rock sample without changing its overall size more accurately reflects the fluid changes during actual fracturing. By constructing a three-dimensional induced stress model in stress interference monitoring and combining it with a dynamic pressure fluctuation correction mechanism, the stress interference effect between wells is quantified, solving the problem of insufficient spatial resolution caused by local discrete points in traditional monitoring methods, and improving the consistency between experimental results and actual fracturing conditions.

Description

Technical Field

[0001] This application relates to the field of oilfield development technology, and in particular to a stress interference monitoring experimental method and a stress interference monitoring experimental device. Background Technology

[0002] Hydraulic fracturing interference refers to the pressure changes and fracture expansion caused by fluid injection during hydraulic fracturing. This not only affects the production of a single well but may also cause pressure interference between wells and even trigger unpredictable formation changes.

[0003] Currently, indoor hydraulic fracturing experiments are an effective means of studying the propagation of fracturing fractures. However, in indoor experiments involving multiple fractures or multiple wells, the problem of crosstalk between wells cannot be effectively monitored, thus making it impossible to quantify the stress field changes at different locations within the rock sample. Summary of the Invention

[0004] This application provides a multi-well true triaxial hydraulic fracturing outlet pressure plate, stress interference monitoring experimental device and method, to achieve the effect of quantifying the stress magnitude at different locations inside the rock sample.

[0005] In a first aspect, embodiments of this application provide a multi-well true triaxial hydraulic fracturing outlet pressure plate, comprising: a pressure plate body 100 and a plurality of metal sliders 200; mounting holes 101 are respectively provided at the four corners of the pressure plate body 100, the mounting holes 101 being used to fix the inner surface of the pressure plate body 100 to the core chamber of a stress interference monitoring experimental device; a rectangular groove 102 is provided in the central region of the outer surface of the pressure plate body 100, the length of the rectangular groove 102 being equal to the length of the pressure plate body 100 and penetrating the pressure plate body 100, and the width of the rectangular groove 102 being equal to the length of the pressure plate body 100. The height of the rectangular groove 102 is equal to the height of each metal slider 200, which is the sum of the widths of the multiple metal sliders 200. The rectangular groove 102 is provided with multiple through slots 103, and fixing holes 104 are symmetrically arranged on both sides of each slot 103. The central area of ​​each metal slider 200 is provided with a mating hole 201, and fixing slots 202 are symmetrically arranged on both sides of the mating hole 201. The mating hole 201 is used to connect the wellbore in the core chamber that passes through the slot 103, and the fixing slot 202 is used to fix the metal slider 200 to the fixing hole 104 of the rectangular groove 102.

[0006] Optionally, multiple through slots 103 are arranged parallel to each other along the width direction of the rectangular groove 102.

[0007] Secondly, embodiments of this application provide a stress interference monitoring experimental device, including: a core chamber, a bearing device, a triaxial stress loading device, a fluid injection system, a pressure monitoring and data acquisition system, and a multi-well true triaxial hydraulic fracturing outlet pressure plate as described in the first aspect above; the core chamber, located inside the bearing device, is used to place the target rock sample; a left pressure plate is provided on the outer side of the left side of the core chamber, an upper pressure plate is provided on the outer side of the upper side of the core chamber, a lower pressure plate is provided on the outer side of the lower side of the core chamber, a front pressure plate is provided on the outer side of the front side of the core chamber, and a rear pressure plate is provided on the outer side of the rear side of the core chamber; the multi-well true triaxial hydraulic fracturing outlet pressure plate is located on the outer side of the outlet of the core chamber; the triaxial stress loading device includes components respectively disposed on the upper pressure plate, the left pressure plate, and the front pressure plate. The outer hydraulic cylinder is used to apply triaxial stress to the target rock sample; the injection system includes a dual-cylinder injection pump, a first fracturing fluid container, a second fracturing fluid container, a first pressure sensor, and a second pressure sensor; the dual-cylinder injection pump is connected to the first fracturing fluid container and the second fracturing fluid container respectively through fracturing pipelines; the first fracturing fluid container is connected to the wellbore of the first simulated well pre-embedded in the target rock sample through a first injection pipeline; the second fracturing fluid container is connected to the wellbore of the second simulated well pre-embedded in the target rock sample through a second injection pipeline; the first pressure sensor is located on the first injection pipeline, and the second pressure sensor is located on the second injection pipeline; the pressure monitoring and data acquisition system is connected to the first pressure sensor, the second pressure sensor, and the dual-cylinder injection pump, and is used to collect and process pressure data.

[0008] Thirdly, embodiments of this application provide a stress interference monitoring experimental method, employing the stress interference monitoring experimental apparatus as described in the second aspect above, comprising: taking a cubic rock sample for stress interference monitoring, sealing the cubic rock sample to obtain a treated rock sample; drilling two simulated wells at preset positions on the treated rock sample, and installing wellbores in each simulated well and cementing them to obtain a target rock sample; placing the target rock sample into a core chamber, and sealing the outlet of the core chamber using a multi-well true triaxial hydraulic fracturing outlet pressure plate; connecting each wellbore to an injection system via injection pipelines; applying triaxial stress to the target rock sample using a triaxial stress loading device; starting a dual-cylinder injection pump to inject fluid into each wellbore, and collecting pressure data from a first pressure sensor and a second pressure sensor through a pressure monitoring and data acquisition system; and calculating the stress state at any location within the target rock sample based on the pressure data.

[0009] In one possible implementation, the cubic rock sample is sealed to obtain a treated rock sample, which includes: coating each face of the cubic rock sample with high-strength epoxy resin; allowing the coated cubic rock sample to stand for a preset time to allow the high-strength epoxy resin to solidify; wrapping the solidified cubic rock sample with a polyolefin film and placing it in a hot oven to allow the polyolefin film to shrink; and cooling the polyolefin film after it shrinks to obtain the treated rock sample.

[0010] In one possible implementation, a dual-cylinder injection pump is activated to inject fluid into each wellbore, and pressure data from a first pressure sensor and a second pressure sensor are collected through a pressure monitoring and data acquisition system. This includes: setting a first injection pressure for the first simulated well and a first injection flow rate for the second simulated well using the dual-cylinder injection pump; injecting fluid into the first and second simulated wells using the dual-cylinder injection pump; recording the instantaneous pressure fluctuation value collected by the first pressure sensor at the moment the target rock sample fractures; setting a second injection flow rate for the first simulated well using the dual-cylinder injection pump, and injecting fluid into the first and second simulated wells using the dual-cylinder injection pump until the target rock sample fractures again.

[0011] In one possible implementation, calculating the stress state at any location within the target rock sample based on pressure data includes: acquiring the current pressure value of a first pressure sensor and determining the pressure value as the current fluid pressure within the fracture; calculating the frictional pressure of the target rock sample based on the pressure decay curve of the dual-cylinder injection pump, wherein the pressure decay curve is acquired through a pressure monitoring and data acquisition system after the dual-cylinder injection pump stops; calculating the net pressure of the fluid within the compressed fracture based on the current fluid pressure within the fracture, the frictional pressure, and the preset minimum horizontal principal stress; measuring the length and height of the main fracture formed after the target rock sample fractures again; establishing a three-dimensional coordinate system with the center of the main fracture as the origin, the direction of the maximum horizontal principal stress as the x-axis, the direction of the minimum horizontal principal stress as the y-axis, and the direction of the perpendicular principal stress as the z-axis; calculating the three-dimensional induced stress component at any location in the three-dimensional coordinate system based on the net pressure of the fluid within the compressed fracture, the length and height of the main fracture; and correcting the three-dimensional induced stress component at any location based on the instantaneous pressure fluctuation value to obtain the actual stress magnitude at any location.

[0012] In one possible implementation, the three-dimensional induced stress component at any location is corrected based on the instantaneous pressure fluctuation value, including: calculating the difference between the instantaneous pressure fluctuation value and the frictional pressure to determine the inter-well stress interference intensity; calculating the difference between the three-dimensional induced stress component and the inter-well stress interference intensity, and determining the absolute value of the difference as a correction coefficient; if the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is greater than or equal to 0, then the actual stress magnitude at any location is the difference between the three-dimensional induced stress component and the correction coefficient; if the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is less than 0, then the actual stress magnitude at any location is the sum of the three-dimensional induced stress component and the correction coefficient.

[0013] In one possible implementation, the formula for calculating the three-dimensional induced stress components at any location is:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] In the formula, σ cxx σ represents the stress component at any location along the x-axis. czz σ represents the stress component along the z-axis at any location; cyy σ represents the stress component at any location along the y-axis; cxz σ represents the stress component at any location in the xz plane; cxy σ represents the stress component at any location in the xy plane; cyz R represents the stress component at any position in the yz plane; R represents the distance from any position to the origin of the three-dimensional coordinate system; R1 represents the distance from any position to the endpoint of the positive direction of the seam length; R2 represents the distance from any position to the endpoint of the negative direction of the seam length; r1 represents the distance from any position to the endpoint of the negative direction of the seam height; r2 represents the distance from any position to the endpoint of the positive direction of the seam height; θ represents the angle between R and the positive direction of the x-axis; θ1 represents the angle between R1 and the positive direction of the x-axis; θ2 represents the angle between R2 and the positive direction of the x-axis; α represents the angle between R and the negative direction of the z-axis; α1 represents the angle between r1 and the negative direction of the z-axis; α2 represents the angle between r2 and the negative direction of the z-axis; H represents the seam height; L represents the seam length; p net ν represents the net pressure of the fluid within the sealed fracture; v represents the Poisson's ratio of the target rock sample.

[0021] In one possible implementation, the formula for calculating the net pressure of the fluid within the sealed joint is:

[0022]

[0023] In the formula, p net This indicates the net pressure of the fluid within the sealed joint; p f p represents the current fluid pressure inside the slit. b Indicates the preset minimum horizontal principal stress; p s This indicates frictional pressure.

[0024] The multi-well true triaxial hydraulic fracturing outlet pressure plate, stress interference monitoring experimental device, and method provided in this application, through a split design of the multi-well true triaxial hydraulic fracturing outlet pressure plate at the core chamber outlet, compensate for the needs of multi-well true triaxial hydraulic fracturing experiments. The split structure of the metal slider and rectangular groove can be freely adjusted and positioned according to the wellbore layout, solving the problem of fixed wellbore position of traditional integral pressure plates. In addition, the rock sample is sealed with high strength without changing the overall size of the cubic rock sample, more realistically reflecting the fluid changes during the actual fracturing process. By constructing a three-dimensional induced stress model in stress interference monitoring and combining it with a dynamic correction mechanism for pressure fluctuations, the stress interference effect between wells is quantified, solving the problem of insufficient spatial resolution caused by local discrete points in traditional monitoring methods, and improving the consistency between experimental results and actual fracturing conditions. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] Figure 1 A schematic diagram of the pressure plate at the outlet of a multi-well true triaxial hydraulic fracturing system provided in this application;

[0027] Figure 2 This is a schematic diagram of the stress interference monitoring experimental device provided in the embodiments of this application;

[0028] Figure 3 This is a flowchart illustrating the stress interference monitoring experimental method provided in the embodiments of this application.

[0029] Figure label:

[0030] 100-Pressure plate body; 200-Metal slider; 101-Mounting hole; 102-Rectangular groove; 103-Groove; 104-Fixing hole; 201-Matching hole; 202-Fixing groove; 301-Core chamber; 302-Bearing device; 303-Triaxial stress loading device; 304-Injection system; 305-Pressure monitoring and data acquisition system; 306-Multi-well true triaxial hydraulic fracturing outlet pressure plate; 303a-Hydraulic cylinder; 304a-Dual-cylinder injection pump; 304b-First fracturing fluid container; 304c-Second fracturing fluid container; 304d-First pressure sensor; 304e-Second pressure sensor.

[0031] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0033] To clearly understand the technical solution of this application, the existing technology solutions are first described in detail. With the continuous growth of global energy demand, the efficient exploitation of oil and gas resources has become an important issue in the energy industry. Hydraulic fracturing technology is widely used because it can effectively increase the production of oil and gas wells. Fracturing crosstalk in the hydraulic fracturing process refers to the pressure changes and fracture propagation caused by the injection of fluid. Recent studies have shown that fracturing crosstalk not only affects the production of a single well but may also lead to pressure interference between wells and even trigger unpredictable formation changes. Currently, laboratory hydraulic fracturing experiments are an effective means of studying fracture propagation. However, in laboratory experiments involving multiple fractures or multiple wells, crosstalk between wells cannot be effectively monitored, thus failing to address the quantitative problem of stress field changes at different locations within real rock samples.

[0034] To address the aforementioned technical challenges, the inventors devised a modular multi-well true triaxial hydraulic fracturing outlet pressure plate design to achieve independent sealing control of multiple wellbores. A through rectangular groove is incorporated into the main body of the pressure plate, with the width of the groove matching the width of the metal slider, forming an independent sealing unit for each wellbore. This multi-well true triaxial hydraulic fracturing outlet pressure plate is integrated into a stress interference monitoring experimental device. A triaxial stress loading device simulates the formation stress field, and a dual-cylinder injection pump and pressure sensor are used to independently monitor the injection pressure of each wellbore. This constructs an experimental system for quantifying inter-well stress interference, solving the current problem that indoor hydraulic fracturing experiments cannot monitor inter-well crosstalk.

[0035] The technical solution of this application and how it solves the above-mentioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0036] Figure 1 The schematic diagram of the multi-well true triaxial hydraulic fracturing outlet pressure plate provided in this application is as follows: Figure 1 As shown, the multi-well true triaxial hydraulic fracturing outlet pressure plate includes: a pressure plate body 100 and multiple metal sliders 200.

[0037] The pressure plate body 100 has mounting holes 101 at its four corners. The mounting holes 101 are used to fix the inner surface of the pressure plate body 100 to the core chamber of the stress interference monitoring experimental device.

[0038] Specifically, mounting holes 101 are countersunk, ensuring the bolt heads are fully recessed into the inner surface of the pressure plate body, resulting in a smooth, unprotruding contact surface between the pressure plate body and the core chamber during installation. The depth of the countersunk hole matches the bolt head height; for example, an M10 bolt corresponds to a 6mm hole depth. The depth is controlled within ±0.03mm using CNC lathe machining, guaranteeing a flatness error of ≤0.03mm on the inner surface of the pressure plate after bolt tightening. The diagonal distance tolerance of the four mounting holes 101 is controlled within ±0.03mm, and coordinate boring machine machining ensures the perpendicularity of the hole axis to the mounting surface is ≤0.1mm.

[0039] A rectangular groove 102 is provided in the central area outside the pressure plate body 100. The length of the rectangular groove 102 is equal to the length of the pressure plate body 100 and passes through the pressure plate body 100. The width of the rectangular groove 102 is equal to the sum of the widths of the multiple metal sliders 200. The height of the rectangular groove 102 is equal to the height of each metal slider 200.

[0040] Specifically, the inner surface of the pressure plate body 100 is fixed to the core chamber of the stress interference monitoring experimental device. A rectangular groove 102 is provided in the central area of ​​the outer surface. The length of the rectangular groove 102 is equal to the overall length of the pressure plate body and extends through the entire pressure plate body 100. The width of the rectangular groove 102 is designed to be the sum of the widths of multiple metal sliders 200. The height of the rectangular groove 102 is consistent with the height of the metal sliders 200, so that the height difference between the outer surface of the metal sliders 200 and the outer plane of the pressure plate body 100 after they are embedded is ≤0.03mm, forming a continuous and flat pressure-bearing surface.

[0041] The rectangular groove 102 is provided with multiple through slots 103, and fixing holes 104 are symmetrically arranged on both sides of each slot 103.

[0042] Specifically, multiple through slots 103 are provided within the rectangular groove 102, the diameter of which is adapted to the outer diameter of the well casing. For example, if the outer diameter of the well casing is 10mm, the corresponding diameter of the slot 103 is 12mm, with a 2mm buffer gap reserved to ensure smooth insertion of the well casing. Fixing holes 104 are symmetrically arranged on both sides of each slot 103. These holes are machined using a CNC drilling and tapping machine to achieve a 6H-grade thread precision, with a hole spacing tolerance of ±0.2mm. A thread plug gauge and vernier caliper are used for dual verification to ensure that the coaxiality of the bolt connection with the fixing slot 202 is ≤0.1mm.

[0043] In this embodiment, multiple through slots 103 are arranged parallel to each other along the width direction of the rectangular groove 102.

[0044] Specifically, multiple through slots 103 are arranged parallel to each other along the width of the rectangular groove 102. The slots 103 are arranged parallel to the width of the rectangular groove 102, so that each wellbore is distributed in a transverse array at the core chamber outlet.

[0045] Each metal slider 200 has a mating hole 201 in the center area, and fixing grooves 202 are symmetrically arranged on both sides of the mating hole 201.

[0046] Specifically, each metal slider 200 has a mating hole 201 in its central area. The inner diameter of the hole is designed to be interference-fitted with the outer diameter of the well shaft. The interference amount is set according to the pressure rating: 0.02mm for ≤30MPa and 0.05mm for 30-50MPa. An annular sealing groove is formed on the inner wall of the mating hole 201 to accommodate a nitrile rubber O-ring. Fixing grooves 202 are symmetrically distributed on both sides of the mating hole 201. The fixing grooves 202 are elongated and fit with the fixing holes 104 on the pressure plate body 100. After the metal slider 200 is installed into the rectangular groove 102, fasteners such as screws are installed at the corresponding positions of the fixing holes 104 and fixing grooves 202 to fix the metal slider 200 onto the pressure plate body 100.

[0047] The mating hole 201 is used to connect the wellbore in the core chamber that passes through the hole groove 103, and the fixing groove 202 is used to fix the metal slider 200 to the fixing hole 104 of the rectangular groove 102.

[0048] Specifically, the mating hole 201 connects to the hole groove 103 in the rectangular groove 102 of the pressure plate body 100, and is coaxially adapted with the well barrel that passes through the core chamber to construct a fluid channel for fracturing fluid injection. The fixing groove 202, in cooperation with the fixing hole 104 on the rectangular groove 102, uses fasteners to limit the metal slider 200 on the pressure plate body 100.

[0049] As demonstrated by the above embodiments, the split design of the multi-well true triaxial hydraulic fracturing outlet pressure plate at the core chamber outlet addresses the requirements of multi-well true triaxial hydraulic fracturing experiments. The split structure of the metal slider and the rectangular groove can be freely adjusted and positioned according to the wellbore layout, solving the problem of fixed wellbore position in traditional integral pressure plates. Furthermore, the metal slider, after being embedded, is at the same height as the outer plane of the pressure plate body, forming a continuous and flat pressure-bearing surface, which can avoid stress concentration problems that may be caused by high-pressure loading on the rock sample during the experiment.

[0050] Figure 2 This is a schematic diagram of the stress disturbance monitoring experimental device provided in the embodiments of this application, as shown below. Figure 2 As shown, the stress interference monitoring experimental device includes: core chamber 301, bearing device 302, triaxial stress loading device 303, injection system 304, pressure monitoring and data acquisition system 305, and multi-well true triaxial hydraulic fracturing outlet pressure plate 306 in the above embodiment.

[0051] The core chamber, located inside the support device, is used to hold the target rock sample.

[0052] A left pressure plate is installed on the outer side of the left side of the core chamber, an upper pressure plate is installed on the outer side of the upper part of the core chamber, a lower pressure plate is installed on the outer side of the lower part of the core chamber, a front pressure plate is installed on the outer side of the front part of the core chamber, and a rear pressure plate is installed on the outer side of the rear part of the core chamber.

[0053] Specifically, the core chamber 301 is located inside the bearing device 302. It is made of high-strength metal material and welded together. The inner wall is treated with rust prevention and is used to fix the target rock sample. The core chamber 301 has a left pressure plate, an upper pressure plate, a lower pressure plate, a front pressure plate, a rear pressure plate, and a multi-well true triaxial hydraulic fracturing outlet pressure plate 306 installed on its six outer sides, forming a closed pressure-bearing space for the rock sample. This ensures that the target rock sample is subjected to uniform stress and that fluid does not leak out during the experiment.

[0054] The pressure plate at the outlet of the multi-well true triaxial hydraulic fracturing system is located outside the outlet of the core chamber.

[0055] Specifically, the multi-well true triaxial hydraulic fracturing outlet pressure plate 306 is installed on the outside of the core chamber outlet. The main body 100 of the pressure plate is fixed to the core chamber through countersunk mounting holes 101 at the four corners. Multiple metal sliders 200 are embedded in the rectangular groove 102 on the outside. The mating hole 201 of each metal slider is interference-fitted with the wellbore through the through-hole groove 103 and sealed by O-rings. The fixing groove 202 is bolted to the fixing hole 104.

[0056] Specifically, the bearing device 302 is a frame structure, welded from H-beams or rectangular steel pipes, with shock-absorbing supports, such as rubber pads, installed at the bottom. Its internal space dimensions are designed according to the core chamber specifications, providing rigid support for the core chamber.

[0057] The triaxial stress loading device includes hydraulic cylinders respectively installed on the outer sides of the upper pressure plate, the left pressure plate and the front pressure plate, for applying triaxial stress to the target rock sample.

[0058] Specifically, the triaxial stress loading device 303 includes hydraulic cylinders 303a respectively installed on the outer sides of the upper pressure plate, left pressure plate, and front pressure plate. Powered by a hydraulic station, the stress values ​​of the upper pressure plate, left pressure plate, and front pressure plate can be adjusted independently. A force sensor is installed between the piston rod of the hydraulic cylinder and the pressure plate to monitor the loading force in real time and simulate the triaxial stress state of the formation.

[0059] The injection system includes a dual-cylinder injection pump 304a, a first fracturing fluid container 304b, a second fracturing fluid container 304c, a first pressure sensor 304d, and a second pressure sensor 304e. The dual-cylinder injection pump 304a is connected to the first fracturing fluid container 304b and the second fracturing fluid container 304c via fracturing pipelines. The first fracturing fluid container 304b is connected to the wellbore of a first simulated well pre-embedded in the target rock sample via a first injection pipeline. The second fracturing fluid container 304c is connected to the wellbore of a second simulated well pre-embedded in the target rock sample via a second injection pipeline.

[0060] The first pressure sensor 304d is located on the first injection line, and the second pressure sensor 304e is located on the second injection line.

[0061] Specifically, the injection system 304 employs a dual-cylinder injection pump 304a, which is connected to the first fracturing fluid container 304b and the second fracturing fluid container 304c via fracturing pipelines, allowing independent control of the injection flow rate and pressure of the two fracturing fluids. The first and second injection pipelines are pre-embedded in the target rock sample, connecting to the wellbores of the first and second simulated wells respectively, enabling synchronous or asynchronous injection across multiple wells to simulate cluster well fracturing operations. The fracturing pipelines are high-pressure hoses with a pressure resistance of 60 MPa.

[0062] The pressure monitoring and data acquisition system is connected to the first pressure sensor 304d, the second pressure sensor, and the dual-cylinder injection pump 304a, and is used to collect and process pressure data.

[0063] Specifically, the pressure monitoring and data acquisition system 305 is connected to the control module of the first pressure sensor 304d, the second pressure sensor 304e, and the dual-cylinder injection pump 304a via a data cable. It collects data such as injection pressure and pump displacement in real time at a sampling frequency of 100Hz, and performs signal processing, curve plotting, and data storage through dedicated software.

[0064] As demonstrated by the above embodiments, the rectangular groove of the multi-well true triaxial hydraulic fracturing outlet pressure plate features parallel arrangement of perforations and slots. Each metal slider independently seals its corresponding wellbore. Combined with the dual-cylinder injection pump and independent pressure sensor of the injection system, the injection pressure and flow rate of fracturing fluid in each well can be controlled synchronously or asynchronously. The triaxial stress loading device applies adjustable triaxial stress to the rock sample via a hydraulic cylinder, simulating the difference in formation principal stress. Combined with the stress concentration control structure of the multi-well true triaxial hydraulic fracturing outlet pressure plate, the stress fluctuation on the rock sample surface is kept ≤5%, ensuring the authenticity of inter-well stress interference. This stress interference monitoring experimental device, through modular design and precise control, achieves realistic simulation of inter-well interference during multi-well fracturing.

[0065] Figure 3 This is a schematic flowchart illustrating the stress interference monitoring experimental method provided in this application embodiment. The stress interference monitoring experimental method employs the stress interference monitoring experimental apparatus described in the above embodiment, such as... Figure 3 As shown, the method includes:

[0066] S301: Take the cubic rock sample for stress disturbance monitoring experiment, seal the cubic rock sample to obtain the treated rock sample.

[0067] Specifically, cubic rock samples that meet the experimental requirements are selected, and the cubic rock samples are sealed. The sealing process includes:

[0068] Sa1: Coat each face of the cubic rock sample with high-strength epoxy resin.

[0069] Specifically, each face of the cubic rock sample is first roughened with 80-grit sandpaper to remove dust and oil stains, then wiped with acetone. Bisphenol A epoxy resin and polyamide curing agent are mixed in a weight ratio of 2:1, and 10% silica powder is added. The mixture is then evenly applied to all six faces of the rock sample with a scraper, with a coating thickness of 0.3-0.5 mm. The corners are touched up with a brush.

[0070] Sa2: Allow the cubic rock sample coated with high-strength epoxy resin to stand for a preset time to allow the high-strength epoxy resin to solidify.

[0071] Specifically, the coated rock sample was placed in an environment with a temperature of 25±2℃ and a humidity of ≤60% for 48 hours, and turned over every 12 hours to ensure uniform stress on all surfaces. After curing, the hardness of the adhesive layer was tested with a Shore hardness tester and found to be 60-70 Shore D. The bond strength was verified to be ≥15MPa through a pull-out test.

[0072] Sa3: A cubic rock sample that has been solidified with high-strength epoxy resin by wrapping it with a polyolefin film and then placing it in a hot oven to shrink the polyolefin film.

[0073] Specifically, a 0.1 mm thick polyolefin film is cut and wrapped around the rock sample. After sealing the seam with a hot melt gun, the sample is placed in a hot air circulating oven and heated to 120 °C at 5 °C / min for 30 minutes. The 15-20% shrinkage rate of the film forms a radial constraint force of 0.1-0.2 MPa on the rock sample, eliminating micro gaps in the adhesive layer.

[0074] Sa4: After the polyolefin film shrinks, it is cooled to obtain the treated rock sample.

[0075] Specifically, after heat preservation, the oven is closed, and the rock sample is allowed to cool naturally to room temperature at a rate of ≤10℃ / h. It is then placed in a -0.09MPa environment for 30 minutes using a vacuum leak test method, observing for bubbles with a diameter ≤1mm and a number ≤3, or confirming a weight change ≤0.1% over 24 hours using a weighing method. This ensures that the permeability of the treated rock sample is ≤ .

[0076] S302: Drill two simulated wells at preset locations on the processed rock sample, and run wellbore into each simulated well and perform cementing treatment to obtain the target rock sample.

[0077] Specifically, two simulated wells were drilled on the rock sample using a CNC drilling machine at a preset well spacing, with a borehole verticality error ≤0.5°. A stainless steel well casing was lowered, with a 15° chamfer machined at the bottom to avoid damaging the rock sample. Cement slurry or high-strength resin was used for cementing, followed by 48 hours of curing. The cementing quality was then checked using an acoustic logging tool to ensure a bond strength ≥20MPa between the well casing and the rock sample.

[0078] S303: Place the target rock sample into the core chamber and seal the outlet of the core chamber using a multi-well true triaxial hydraulic fracturing outlet pressure plate.

[0079] Specifically, the target rock sample is placed in the center of the core chamber, and pressure plates are installed on all six sides of the core chamber. The pressure plates at the outlet of the multi-well true triaxial hydraulic fracturing are fixed to the outlet of the core chamber through the mounting holes at the four corners. Metal sliders are embedded in the rectangular grooves. The process involves first passing the wellbore through the slot, then fitting the metal slider into the wellbore through the matching hole, and fixing it with bolts through the fixing slot and fixing hole. After installation, a pressure test is performed to ensure a seal.

[0080] S304: Connect each wellbore to the injection system via injection pipelines.

[0081] Specifically, high-pressure hoses are used to connect the wellbore and the injection system: the first simulated well is connected to the first fracturing fluid container via the first injection line, and the second simulated well is connected to the second fracturing fluid container via the second injection line. Metal-sealed joints are used at the pipeline connections, and the airtightness is checked with soapy water to ensure no air bubbles are generated. Pressure sensors are installed in series on the injection lines, at a distance ≤100mm from the rock sample inlet.

[0082] S305: Apply triaxial stress to the target rock sample using a triaxial stress loading device.

[0083] Specifically, the triaxial stress loading device was activated, and stress was applied in stages through the upper, left, and front hydraulic cylinders: first, the confining pressure was loaded to the target value, and then the vertical stress was loaded to the set value. The loading rate was controlled at 0.5 MPa / min. After reaching the target value, the pressure was maintained for 30 minutes to stabilize the stress state of the rock sample. During the stress loading process, the force sensor was used for real-time monitoring to ensure that the triaxial stress deviation was ≤ ±0.3 MPa.

[0084] S306: Start the dual-cylinder injection pump to inject fluid into each wellbore, and collect pressure data from the first and second pressure sensors through the pressure monitoring and data acquisition system.

[0085] Specifically, the dual-cylinder injection pump is started, and fluid is injected synchronously into both wellbores according to the preset displacement. The injection pressure is gradually increased until the rock sample fractures. The first and second pressure sensors acquire pressure data at a frequency of 100Hz. The data acquisition system records the pressure-time curve in real time and automatically marks the fracture pressure and propagation pressure. This process includes:

[0086] Sb1: The first injection pressure of the first simulated well and the first injection flow rate of the second simulated well are set by a dual-cylinder injection pump.

[0087] Specifically, the first injection pressure of the first simulated well and the first injection flow rate of the second simulated well are independently set through the control system of the dual-cylinder injection pump.

[0088] Sb2: Fluid is injected into the first and second simulated wells via a dual-cylinder injection pump.

[0089] Specifically, a dual-cylinder injection pump is started to inject fluid into two simulated wells simultaneously. The first and second pressure sensors collect injection pressure data in real time at a frequency of 100Hz, and the data acquisition system records the pressure-time curve and pump displacement parameters simultaneously.

[0090] Sb3: Record the instantaneous pressure fluctuation value collected by the first pressure sensor at the moment the target rock sample fractures.

[0091] Specifically, when the target rock sample reaches the fracturing pressure (a sudden drop in the curve appears), the system automatically marks the fracturing moment and records the instantaneous pressure fluctuation value of the first pressure sensor. The instantaneous pressure fluctuation value is the stress interference on the bottom of the first simulated well during the fracturing process of the second simulated well.

[0092] Sb4: The second injection flow rate of the first simulated well is set by a dual-cylinder injection pump, and the fluid is injected into the first and second simulated wells by the dual-cylinder injection pump until the target rock sample is fractured again.

[0093] Specifically, the flow rate of the dual-cylinder injection pump was adjusted to change the flow rate of the first simulated well to that of the second injection well, while keeping the flow rate of the second simulated well unchanged, and injection continued into both wells until the rock sample fractured again.

[0094] S307: Calculate the stress state at any location within the target rock sample based on pressure data.

[0095] Specifically, using the injection pressure and triaxial loading stress of each wellbore as boundary conditions, a three-dimensional stress model of the rock sample is established, and the magnitude and direction of the principal stress at any location are calculated. This process includes:

[0096] Sc1: Collect the current pressure value of the first pressure sensor and determine the pressure value as the current fluid pressure inside the gap.

[0097] Specifically, the current pressure value of the first pressure sensor is collected in real time through a pressure monitoring and data acquisition system, and directly determined as the current fluid pressure inside the gap.

[0098] Sc2: Calculate the frictional pressure of the target rock sample based on the pressure decay curve of the dual-cylinder injection pump. The pressure decay curve is obtained by the pressure monitoring and data acquisition system after the dual-cylinder injection pump stops.

[0099] Specifically, after the dual-cylinder injection pump stops, the pressure decay curve of the dual-cylinder injection pump is collected using a pressure monitoring and data acquisition system. The frictional pressure of the target rock sample is then calculated based on this curve. The formula for fitting the pressure decay curve using an exponential decay model is as follows:

[0100]

[0101] In the formula, P t P represents the pressure value at time t after the pump stops; P0 represents the pressure at the instant the pump stops; k represents the attenuation coefficient, P res This indicates residual pressure.

[0102] Specifically, the frictional pressure is the difference between the pressure at the instant the pump stops and the residual pressure.

[0103] Sc3: Calculate the net pressure of the fluid in the pressurized joint based on the current fluid pressure, frictional pressure, and preset minimum horizontal principal stress.

[0104] Among them, the net pressure of the fluid inside the fractured fracture reflects the effective pressure that the fracturing fluid exerts to promote fracture propagation after overcoming friction and minimum horizontal principal stress within the fracture.

[0105] Specifically, based on the current fluid pressure within the joint, the frictional pressure, and the preset minimum horizontal principal stress, the formula for calculating the net fluid pressure within the pressurized joint is as follows:

[0106]

[0107] In the formula, P net P represents the net pressure of the fluid within the sealed joint. f P represents the current fluid pressure inside the gap. b P represents the preset minimum horizontal principal stress. s This indicates frictional pressure.

[0108] Sc4: Measure the length and height of the main fracture formed after the target rock sample fractures again.

[0109] Specifically, after the target rock sample fractures again, the length and height of the main fracture are measured using equipment such as an ultrasonic flaw detector or a 3D laser scanner. During measurement, the center of the main fracture is used as the reference point; the fracture length is measured along the direction of the maximum horizontal principal stress, and the fracture height is measured along the vertical direction.

[0110] Sc5: Establish a three-dimensional coordinate system with the center of the main seam as the origin, the direction of the maximum horizontal principal stress as the x-axis, the direction of the minimum horizontal principal stress as the y-axis, and the direction of the vertical principal stress as the z-axis.

[0111] Specifically, a three-dimensional coordinate system is established with the center of the main seam as the origin, the direction of the maximum horizontal principal stress as the x-axis, the direction of the minimum horizontal principal stress as the y-axis, and the direction of the vertical principal stress as the z-axis.

[0112] Sc6: In a three-dimensional coordinate system, calculate the three-dimensional induced stress components at any location based on the net pressure of the fluid in the pressurized joint, the length of the main joint, and the joint height.

[0113] Specifically, in the established three-dimensional coordinate system, based on the net fluid pressure within the sealed joint, the length of the main joint, and the joint height, the formula for calculating the three-dimensional induced stress components at any location is as follows:

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] In the formula, σ cxx σ represents the stress component at any location along the x-axis. czz σ represents the stress component along the z-axis at any location; cyy σ represents the stress component at any location along the y-axis; cxz σ represents the stress component at any location in the xz plane; cxy σ represents the stress component at any location in the xy plane; cyz R represents the stress component at any position in the yz plane; R represents the distance from any position to the origin of the three-dimensional coordinate system; R1 represents the distance from any position to the endpoint of the positive direction of the seam length; R2 represents the distance from any position to the endpoint of the negative direction of the seam length; r1 represents the distance from any position to the endpoint of the negative direction of the seam height; r2 represents the distance from any position to the endpoint of the positive direction of the seam height; θ represents the angle between R and the positive direction of the x-axis; θ1 represents the angle between R1 and the positive direction of the x-axis; θ2 represents the angle between R2 and the positive direction of the x-axis; α represents the angle between R and the negative direction of the z-axis; α1 represents the angle between r1 and the negative direction of the z-axis; α2 represents the angle between r2 and the negative direction of the z-axis; H represents the seam height; L represents the seam length; p net ν represents the net pressure of the fluid within the sealed fracture; v represents the Poisson's ratio of the target rock sample.

[0121] Sc7: Based on the instantaneous pressure fluctuation value, the three-dimensional induced stress component at any location is corrected to obtain the actual stress magnitude at any location.

[0122] Specifically, the pressure fluctuation value reflects the abrupt change in stress at the moment of rupture. The induced stress is corrected by superimposing the stress increment caused by the pressure fluctuation onto the induced stress component. Specifically, the correction methods include:

[0123] Sd1: Calculate the difference between the instantaneous pressure fluctuation value and the friction pressure to determine the intensity of inter-well stress interference.

[0124] Specifically, the pressure fluctuation value at the moment of rock sample fracturing is obtained through a pressure monitoring system, and the difference between this value and the frictional pressure calculated after pump shutdown is used to obtain the inter-well stress interference intensity. This value eliminates the influence of fluid flow resistance and quantifies the degree of stress interference caused by fluid injection in adjacent wells on the fracture propagation of the target well during multi-well fracturing.

[0125] Sd2: Calculate the difference between the three-dimensional induced stress components and the inter-well stress interference intensity, and determine the absolute value of the difference as the correction coefficient.

[0126] Specifically, the difference between the three-dimensional induced stress components and the inter-well stress interference intensity is calculated, and the absolute value of the difference is used as a correction coefficient. This coefficient is used to quantify the degree of deviation between the theoretically calculated induced stress value and the actual stress interference effect.

[0127] Sd3: If the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is greater than or equal to 0, then the actual stress magnitude at any location is the difference between the three-dimensional induced stress component and the correction coefficient.

[0128] Specifically, when the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is greater than or equal to 0, the actual stress magnitude is the induced stress component minus the correction factor. This applies to areas far from the fracture center, where the induced stress dominates, and the calculation results need to be made closer to the actual stress state by subtracting the deviation.

[0129] Sd4: If the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is less than 0, then the actual stress magnitude at any location is the sum of the three-dimensional induced stress component and the correction coefficient.

[0130] Specifically, when the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is less than 0, the actual stress magnitude is the induced stress component plus a correction factor. This applies to the near-field region of the fracture, where the pressure fluctuation at the moment of rupture will cause a significant dynamic stress increment, requiring the overlay of a correction factor to compensate for the inadequacy of the induced stress calculation.

[0131] As can be seen from the above embodiments, by sealing the cubic rock sample, a high-strength seal is achieved without changing the overall size of the cubic rock sample, ensuring that it remains in a closed boundary state throughout the stress interference monitoring experiment. Even if the fracturing crack extends to the surface of the rock mass, the fracturing fluid inside the crack will not be filtered out from the crack, thus preventing the loss of fluid pressure inside the crack. This more realistically reproduces the fluid changes during the actual long-distance fracturing process and ensures the accuracy and precision for monitoring stress interference within the rock sample and inter-well crosstalk.

[0132] In addition, by constructing a three-dimensional induced stress model in stress interference monitoring and combining it with a dynamic correction mechanism for pressure fluctuations, the stress interference effect between wells is quantified, which solves the problem of insufficient spatial resolution caused by local discrete points in traditional monitoring methods. This enables real-time inversion of the stress state at any location within the rock sample, effectively improving the consistency between experimental results and actual fracturing conditions.

[0133] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0134] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0135] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A stress disturbance monitoring experimental method, characterized in that, Applications in stress disturbance monitoring experimental devices include: Take a cubic rock sample for stress disturbance monitoring experiment, and seal the cubic rock sample to obtain the treated rock sample; Two simulated wells were drilled at preset positions on the processed rock sample, and wellbore was installed in each simulated well and cemented to obtain the target rock sample. The target rock sample is placed into the core chamber, and the outlet of the core chamber is sealed using a multi-well true triaxial hydraulic fracturing outlet pressure plate. The multi-well true triaxial hydraulic fracturing outlet pressure plate includes: a pressure plate body (100) and multiple metal sliders (200); the four corners of the pressure plate body (100) are respectively provided with mounting holes (101), which are used to fix the inner surface of the pressure plate body (100) to the core chamber of the stress interference monitoring experimental device; a rectangular groove (102) is provided in the central area of ​​the outer side of the pressure plate body (100), the length of the rectangular groove (102) is equal to the length of the pressure plate body (100) and penetrates through the pressure plate body (100), and the width of the rectangular groove (102) is equal to the length of the multiple metal sliders (200). The sum of the widths of the rectangular groove (102) and the height of the rectangular groove (102) are equal to the height of each metal slider (200); the rectangular groove (102) is provided with multiple through slots (103), which are arranged parallel to the width direction of the rectangular groove (102); fixing holes (104) are symmetrically arranged on both sides of each slot (103); each metal slider (200) is provided with a mating hole (201) in the central area, and fixing slots (202) are symmetrically arranged on both sides of the mating hole (201); the mating hole (201) is used to connect the wellbore in the core chamber that passes through the slot (103), and the fixing slots (202) are used to fix the metal slider (200) to the fixing holes (104) of the rectangular groove (102); Connect each wellbore to the injection system via injection pipelines; Triaxial stress is applied to the target rock sample using a triaxial stress loading device; Start the dual-cylinder injection pump to inject fluid into each wellbore, and collect pressure data from the first and second pressure sensors through the pressure monitoring and data acquisition system. At the moment the target rock sample fractures, the instantaneous pressure fluctuation value collected by the first pressure sensor is recorded; Collect the current pressure value of the first pressure sensor and determine the pressure value as the current fluid pressure inside the gap; The frictional pressure of the target rock sample is calculated based on the pressure decay curve of the dual-cylinder injection pump, wherein the pressure decay curve is obtained by a pressure monitoring and data acquisition system after the dual-cylinder injection pump is stopped. Calculate the net pressure of the fluid in the compressed joint based on the current fluid pressure inside the joint, the frictional pressure, and the preset minimum horizontal principal stress. Measure the length and height of the main fracture formed after the target rock sample fractures again; A three-dimensional coordinate system is established with the center of the main seam as the origin, the direction of the maximum horizontal principal stress as the x-axis, the direction of the minimum horizontal principal stress as the y-axis, and the direction of the vertical principal stress as the z-axis. In the three-dimensional coordinate system, the three-dimensional induced stress components at any position are calculated based on the net pressure of the fluid in the pressurized joint, the length and height of the main joint. The difference between the instantaneous pressure fluctuation value and the frictional pressure is calculated to determine the intensity of inter-well stress interference. Calculate the difference between the three-dimensional induced stress components and the inter-well stress interference intensity, and determine the absolute value of the difference as a correction coefficient; If the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is greater than or equal to 0, then the actual stress magnitude at any location is the difference between the three-dimensional induced stress component and the correction coefficient. If the difference between the three-dimensional induced stress component and the inter-well stress interference intensity is less than 0, then the actual stress magnitude at any location is the sum of the three-dimensional induced stress component and the correction coefficient.

2. The method according to claim 1, characterized in that, The process of sealing the cubic rock sample to obtain the treated rock sample includes: Each face of the cubic rock sample was coated with high-strength epoxy resin. The cubic rock sample coated with the high-strength epoxy resin adhesive was left to stand for a preset time to allow the high-strength epoxy resin adhesive to solidify. The cubic rock sample, after being solidified with high-strength epoxy resin, was wrapped with a polyolefin film and placed in a hot oven to shrink the polyolefin film. After the polyolefin film shrinks, it is cooled to obtain the treated rock sample.

3. The method according to claim 1, characterized in that, The process of starting the dual-cylinder injection pump to inject fluid into each wellbore, and collecting pressure data from the first pressure sensor and the second pressure sensor through the pressure monitoring and data acquisition system, includes: The first injection pressure of the first simulated well and the first injection flow rate of the second simulated well are set by the dual-cylinder injection pump. Fluid is injected into the first simulated well and the second simulated well using the dual-cylinder injection pump; The second injection flow rate of the first simulated well is set by the dual-cylinder injection pump, and the fluid is injected into the first simulated well and the second simulated well through the dual-cylinder injection pump until the target rock sample fractures again.

4. The method according to claim 1, characterized in that, The formula for calculating the three-dimensional induced stress components at any given location is: In the formula, σ cxx σ represents the stress component in the x-axis direction at any given location; czz σ represents the stress component along the z-axis at any given location; cyy σ represents the stress component in the y-axis direction at any given location; cxz σ represents the stress component at any given location in the xz plane; cxy σ represents the stress component in the xy plane at any given location; cyz R represents the stress component at any given position in the yz plane; R represents the distance from any given position to the origin of the three-dimensional coordinate system; R1 represents the distance from any given position to the endpoint of the positive direction of the seam length; R2 represents the distance from any given position to the endpoint of the negative direction of the seam length; r1 represents the distance from any given position to the endpoint of the negative direction of the seam height; r2 represents the distance from any given position to the endpoint of the positive direction of the seam height; θ represents the angle between R and the positive x-axis; θ1 represents the angle between R1 and the positive x-axis; θ2 represents the angle between R2 and the positive x-axis; α represents the angle between R and the negative z-axis; α1 represents the angle between r1 and the negative z-axis; α2 represents the angle between r2 and the negative z-axis; H represents the seam height; L represents the seam length; p net represents the net pressure of the fluid within the sealed fracture; v represents the Poisson's ratio of the target rock sample.

5. The method according to claim 1, characterized in that, The formula for calculating the net pressure of the fluid within the sealed joint is as follows: In the formula, p net p represents the net pressure of the fluid within the sealed joint. f This indicates the current fluid pressure within the slit; p b This represents the preset minimum horizontal principal stress; p s This indicates the frictional pressure.

6. The method according to any one of claims 1 to 5, characterized in that, The stress interference monitoring experimental device includes: a bearing device, a core chamber, a triaxial stress loading device, a fluid injection system, a pressure monitoring and data acquisition system, and a multi-well true triaxial hydraulic fracturing outlet pressure plate; The core chamber, located inside the support device, is used to hold the target rock sample; A left pressure plate is provided on the outer side of the left side of the core chamber, an upper pressure plate is provided on the outer side of the upper side of the core chamber, a lower pressure plate is provided on the outer side of the lower side of the core chamber, a front pressure plate is provided on the outer side of the front side of the core chamber, and a rear pressure plate is provided on the outer side of the rear side of the core chamber. The multi-well true triaxial hydraulic fracturing outlet pressure plate is located outside the outlet of the core chamber; The triaxial stress loading device includes hydraulic cylinders respectively disposed on the outer sides of the upper pressure plate, the left pressure plate and the front pressure plate, for applying triaxial stress to the target rock sample; The injection system includes a dual-cylinder injection pump, a first fracturing fluid container, a second fracturing fluid container, a first pressure sensor, and a second pressure sensor. The dual-cylinder injection pump is connected to the first fracturing fluid container and the second fracturing fluid container via fracturing pipelines. The first fracturing fluid container is connected to the wellbore of a first simulated well pre-embedded in the target rock sample via a first injection pipeline. The second fracturing fluid container is connected to the wellbore of a second simulated well pre-embedded in the target rock sample via a second injection pipeline. The first pressure sensor is located on the first injection line, and the second pressure sensor is located on the second injection line; The pressure monitoring and data acquisition system is connected to the first pressure sensor, the second pressure sensor and the dual-cylinder injection pump, and is used to collect and process pressure data.

Images