Device for testing performance of acid fracturing fluid

Abstract

The invention discloses an acid fracturing fluid performance testing device. The device comprises a mounting cylinder; the clamping device is composed of two symmetrical hollow semi-cylindrical clamping pieces and is vertically arranged in the mounting cylinder; the fixed end of each pushing device is fixed at the bottom of the mounting cylinder; the top of the pushing end of each pushing device is provided with one supporting plate, and at least one supporting plate is arranged below each clamping piece; moreover, the plurality of pushing devices push the plurality of supporting plates to move vertically, so that the clamping device is driven to move in the direction of entering the mounting cylinder and the direction of leaving the mounting cylinder. And moreover, a limiting piece for limiting the separation of the two clamping pieces is further arranged on the movement path of the clamping device. According to the invention, the taking and placing process of the holder is simplified.

Description

Technical Field

[0001] The present invention relates to the field of petroleum engineering experimental equipment, and more specifically, to an acid fracturing fluid performance testing device. Background Art

[0002] In the field of oil industry, acid fracturing technology is a critical means of increasing production. Its core principle is to inject acid fracturing fluid into the reservoir under the condition of higher than the reservoir fracture pressure or natural fracture closure pressure. The acid fracturing fluid reacts chemically with the reservoir rock, dissolving part of the rock, and at the same time forms artificial fractures with high conductivity under the action of pressure, thereby greatly improving the flow channel of oil and gas in the reservoir and significantly increasing the production of oil and gas wells.

[0003] The precise testing of the performance of acid fracturing fluid plays a decisive role in optimizing the acid fracturing technology. Through precise testing, key parameters such as the reaction characteristics, corrosion degree, and impact on rock mechanical properties of acid fracturing fluid under different reservoir conditions can be clarified. These parameters provide a scientific basis for technicians to rationally select the formula of acid fracturing fluid, determine the optimal construction pressure and injection volume, and thus effectively improve oil and gas production efficiency, reduce production costs, and enhance the effective development and utilization of oil resources. However, the existing acid fracturing fluid performance testing equipment has many problems and needs to be improved.

[0004] Taking the acid fracturing fluid performance test device disclosed in the Chinese patent authorization announcement number CN 214539580 U as an example, its clamp has significant inconvenience in taking and placing. The clamp of the device fixes the core by cooperating with the fixed rod, slider, spring, conical cover and guide groove. When taking and placing the core, the operator needs to remove the fixed rod, slider and other components first. Since these components are interrelated and compactly arranged, it is very easy for the components to get stuck or fall off during the removal process. During installation, it is necessary to ensure that each component is accurately reset, and the matching accuracy between the components is extremely high. If there is a slight deviation, the fixing operation cannot be completed normally. The entire picking and placing process not only has many operating steps, but also requires high technical proficiency and patience of the operator. It often takes several times more time to take and place the core than conventional operations, which greatly affects the efficiency of the experiment.

[0005] Therefore, it is urgent to improve the gripper pick-up and placement design of the existing acid fracturing fluid performance testing device to meet the needs of efficient experiments and promote the further development of acid fracturing technology. Summary of the invention

[0006] The purpose of the present invention is to provide an acid fracturing fluid performance testing device, which provides a pushing device at the bottom of the installation tube, cooperates with the support plate to drive the clamp to move in the direction of entering and leaving the installation tube, so that the clamp can be quickly moved out of and into the installation tube, simplifies the clamp's placement process, avoids the inconvenience of complex disassembly and installation when the clamp is placed in the traditional device, and greatly improves the operating efficiency.

[0007] In order to achieve these purposes and other advantages of the present invention, a device for testing the performance of acid fracturing fluid is provided, comprising: Install the barrel; The clamp is composed of two symmetrical hollow semi-cylindrical clamping parts and is vertically arranged in the mounting cylinder; A plurality of pushing devices, wherein the fixed ends of the pushing devices are respectively fixed to the bottom of the mounting tube; A plurality of support plates, wherein a support plate is disposed on the top of the push end of each push device, and at least one support plate is disposed under each clamping member; Wherein, the plurality of pushing devices push the plurality of supporting plates to move vertically, so as to drive the clamper to move in the direction of entering the installation tube and leaving the installation tube; Furthermore, a limiting member for limiting the separation of the two clamping members is provided on the moving path of the clamp.

[0008] Preferably, in the acid fracturing fluid performance testing device, an opening is provided in the center of the top of the clamp, the contact parts of the two clamps are overlapped, a sealing member is provided at the overlap of the two clamps, a supporting block is provided at the bottom of each of the two clamps, and both supporting blocks are placed on the bottom of the mounting tube to support the two clamps.

[0009] Preferably, the acid fracturing fluid performance testing device further comprises: The liquid inlet hood is composed of two symmetrical semi-cylindrical hoods, which are vertically arranged on the top of the clamp and are made of transparent corrosion-resistant material. The two hoods are respectively fixed on the two clamps, the interiors of the two hoods are opposite to the open mouth, the contact parts of the two hoods are overlapped, and a sealing member is arranged at the overlap of the two hoods. The liquid inlet hood is provided with a liquid inlet port and a liquid discharge port, and a sealing cover is arranged on the top of the liquid inlet hood, and the sealing cover is fixed on one of the two hoods.

[0010] Preferably, the acid fracturing fluid performance testing device further comprises: Multiple driving devices, multiple driving devices are arranged between the outer wall of each clamping member and the inner wall of the mounting tube, the fixed end of each driving device is fixed to the inner wall of the mounting tube, a linear displacement sensor is installed near the end of the movable end of each driving device, and the movable end of each driving device selectively contacts with the corresponding clamping member; A plurality of pressure sensors, wherein at least one pressure sensor is respectively arranged on the movable end of each driving device and at the position in contact with the corresponding clamping member; Control unit; A data acquisition module, which is connected to the control unit and each pressure sensor, each drive device, each linear displacement sensor, and each pushing device, and is used to collect data transmitted by each pressure sensor, each drive device, each linear displacement sensor, and each pushing device, and transmit the data to the control unit; The driving module is connected with the control unit, the driving device and the pushing device, and is used to obtain data transmitted by the control unit and provide driving signals for the driving device and the pushing device.

[0011] Preferably, in the acid fracturing fluid performance testing device, the multiple driving devices include multiple pairs of driving devices, the multiple pairs of driving devices are arranged at equal intervals along the circumferential direction of the clamp, and each pair of drivers is spaced apart in the vertical direction and symmetrically arranged.

[0012] Preferably, in the acid fracturing fluid performance testing device, the stopper comprises: The first limiting ring is in the shape of a circular ring and is fixed on the outer edge of each supporting plate and is located below each driving device; when each supporting plate is respectively located below the corresponding clamping member and is separated from the corresponding clamping member by a preset distance, the height of the first limiting ring is lower than the height of the bottom of the clamp; when the top of each supporting plate is flush with or in contact with the bottom of the clamp, the inner side wall of the first limiting ring is in contact with or has a gap with the outer side wall of the lower part of the clamp, and the first limiting ring is separated from each driving device by a preset distance; the movable end of each driving device can be retracted to not be opposite to the first limiting ring; The second limiting ring is annular and fixed on the mounting tube. The clamp is located inside the second limiting ring. There is a gap between the inner side wall of the second limiting ring and the outer side wall of the upper part of the clamp.

[0013] Preferably, in the acid fracturing fluid performance testing device, the mounting tube is U-shaped; The acid fracturing fluid performance testing device also includes: The bracket is U-shaped, the mounting tube is located inside the bracket and is rotatably connected to the bracket, the two vertical parts of the mounting tube are respectively rotatably connected to the two vertical parts of the bracket through a rotating shaft, one end of each rotating shaft is respectively fixedly connected to the vertical part of the mounting tube corresponding thereto, and the other end is respectively rotatably connected to the vertical part of the bracket corresponding thereto, and one of the two rotating shafts rotates under the drive of a power device; the power device is connected to a control unit, a data acquisition module, and a driving module.

[0014] Preferably, in the acid fracturing fluid performance testing device, the inner diameter of the first limiting ring gradually decreases from top to bottom.

[0015] Preferably, in the acid fracturing fluid performance testing device, there are four pairs of driving devices, and the movable ends of two pairs of driving devices among the four pairs of driving devices can respectively contact the middle parts of the corresponding clamping members.

[0016] The present invention has at least the following beneficial effects: The present invention provides a pushing device at the bottom of the installation tube, which cooperates with the support plate to drive the clamper to move in the direction of entering and leaving the installation tube, so that the clamper can be quickly moved out of and into the installation tube, which simplifies the process of taking and placing the clamper, avoids the inconvenience of complex disassembly and installation when taking and placing the clamper in traditional devices, and greatly improves the operating efficiency.

[0017] The present invention adopts two symmetrical hollow semi-cylindrical clamping parts to form a clamp, and sets a limiter on the movement path of the clamping parts to effectively limit the separation of the two clamping parts, thereby ensuring that the clamp always maintains a stable structural form during the removal and placement of the clamp and the experiment process, thereby ensuring the reliability of core fixation and improving the accuracy of the experimental results.

[0018] The present invention utilizes a pushing device to uniformly control the vertical movement of the support plate, thereby driving the overall movement of the clamp. Compared with the traditional multi-component decentralized operation method, the operation steps and complexity are greatly reduced. The operator only needs to control the pushing device to easily complete the pick-up and placement operations of the clamp, which reduces the difficulty of operation and improves work efficiency.

[0019] The multiple drive devices in the clamping system of the present invention cooperate with linear displacement sensors and pressure sensors to monitor and adjust the clamping force in real time and accurately. The linear displacement sensor is installed inside the active end of the drive device near the end position, which can accurately sense the extension and contraction state of the drive device, and the pressure sensor accurately measures the clamping force. The two work together to ensure that the clamping force is stable at the required level, effectively avoiding the adverse effects of clamping force fluctuations on experimental results, and greatly improving the accuracy and reliability of experimental data. For example, in experiments to study the effect of acid fracturing fluid on core permeability, stable clamping force can ensure that the core microstructure is not subject to additional interference, thereby obtaining accurate permeability data.

[0020] The design of the adjustment mechanism of the present invention greatly facilitates the core loading and unloading operations. Multiple pushing devices cooperate with the support plate, and the operator can easily control the lifting and lowering of the support plate through the control system, providing sufficient space for placing or removing the clamp and the core. At the same time, the support block at the bottom of the clamp is placed on the bottom of the installation tube, ensuring the stable support of the clamp during the working process, reducing the risk of shaking and displacement, and further ensuring the smooth progress of the experiment.

[0021] The liquid inlet hood of the liquid inlet system of the present invention is composed of two symmetrical semi-cylindrical hoods, which are respectively fixed on two clamps. This structure cooperates closely with the clamp, so that the acid fracturing fluid can flow accurately to the core surface to avoid liquid splashing or uneven distribution. The cover on the top of the liquid inlet hood and the seal at the overlap effectively prevent liquid leakage, reduce experimental errors, and protect the internal components of the device from liquid erosion. The liquid inlet hood is made of transparent corrosion-resistant material, which not only meets the requirements of the chemical corrosion-resistant experimental environment, but also facilitates the operator to observe the flow and reaction of the liquid on the core surface in real time, providing convenience for monitoring the experimental process.

[0022] The multiple driving devices of the present invention include multiple pairs of driving devices, which are evenly spaced along the circumference of the clamp, and each pair of driving devices is spaced in the vertical direction and symmetrically arranged. This layout enables the clamping force to be evenly distributed on the clamp, ensuring that the core can be firmly clamped in all directions, thereby enhancing the stability of the device.

[0023] The first limit ring of the present invention plays a multiple role in ensuring the operation of the device. Its annular structure is fixed on the support plate. When the support plate is located below the clamp, the specific position relationship between the clamp and the drive device can not only assist in positioning during core loading and unloading and prevent excessive separation of the clamp, but also will not interfere with the normal operation of the drive device. Moreover, the inner diameter of the first limit ring gradually decreases from top to bottom. This design can better guide the clamp to return to its position and further improve operational stability. In addition, the second limit ring is fixed on the mounting tube and maintains a gap with the upper outer wall of the clamp. Under the premise of not affecting the normal operation of the clamp, it plays an additional role in limiting and straightening the clamp, avoiding the displacement of the clamp during the experiment and ensuring the accuracy of the experiment.

[0024] The mounting tube of the present invention is U-shaped and rotatably connected to the bracket. The power device drives the rotating shaft to rotate, which can realize the precise rotation of the mounting tube, thereby flexibly adjusting the core angle. When studying the erosion effect of acid fracturing fluid on the core at different formation fracture angles, the operator can accurately set the core angle through the control system according to the experimental requirements, simulate the real formation environment, provide more practical data support for the optimization of acid fracturing technology, and broaden the depth and breadth of the experiment.

[0025] The overall layout of the components of the device of the present invention is compact and reasonable, and the bracket, mounting tube, clamping system, liquid inlet system and control system cooperate with each other and work in coordination. It not only meets the functional requirements, but also saves space, reduces the footprint of the device, is convenient for installation and use in limited spaces such as laboratories, and improves the practicality of the device. At the same time, the clear connection relationship and relative position between the components make the assembly, debugging and maintenance of the device more convenient, reducing the use cost and operation difficulty.

[0026] The acid fracturing fluid performance testing device of the present invention is optimized and innovated in many aspects such as clamping, fluid feeding, adjustment, and control, which effectively solves the problems existing in the existing testing devices, provides an efficient, accurate, and reliable experimental platform for acid fracturing fluid performance testing, and effectively promotes the research and development of acid fracturing technology in the field of petroleum extraction.

[0027] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of an acid fracturing fluid performance testing device according to an embodiment of the present invention; Among them, the bracket-1; the mounting tube-2; the clamp-3; the support block-301; the core-4; the driving device-5; the pushing device-6; the support plate-7; the first limiting ring-8; the liquid inlet cover-9; the second limiting ring-10; the rotating shaft-11; and the power device-12. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0030] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] like Figure 1 As shown, the present invention provides an acid fracturing fluid performance testing device, comprising: Install the cylinder 2; The clamp 3 is composed of two symmetrical hollow semi-cylindrical clamping parts and is vertically arranged in the mounting tube 2; A plurality of pushing devices 6, wherein the fixed ends of the pushing devices 6 are respectively fixed to the bottom of the mounting tube 2; There are multiple support plates 7, one support plate 7 is provided on the top of each push end of each push device 6, and at least one support plate 7 is provided under each clamping member; the operator controls the lifting and lowering of the support plates 7 through the control system, providing sufficient space for loading and unloading the core 4 and the clamp 3, which greatly facilitates the operation. The push device 6 is usually an electric push rod, driven by a stainless steel rod body and a servo motor, with a fast response speed and a position control accuracy of up to ±0.2mm. The support plates 7 are accurately lifted and lowered according to the control system instructions to ensure efficient and safe loading and unloading of the core 4.

[0032] The plurality of pushing devices 6 push the plurality of supporting plates 7 to move vertically, so as to drive the clamper 3 to move in the direction of entering the installation tube 2 and leaving the installation tube 2; Furthermore, a limiting member for limiting the separation of the two clamping members is provided on the moving path of the clamping device 3 .

[0033] The working principle of the acid fracturing fluid performance test device in this scheme: A plurality of pushers 6 are fixed at the bottom of the installation tube 2, and the support plate 7 at the top of the pusher end contacts the bottom of the clamp 3. When the pusher 6 is in operation, the force is transmitted to the clamp 3 through the support plate 7, so that the clamp 3 moves vertically in the direction of entering or leaving the installation tube 2. This force transmission principle is based on which the position adjustment of the clamp 3 is realized in different working stages, meeting the requirements of loading and unloading and testing of the core 4.

[0034] The clamp 3 is composed of two symmetrical hollow semi-cylindrical clamps. By utilizing the mechanical stability of the symmetrical structure, the clamping force can be uniformly applied to the core 4 when placing the core 4, ensuring that the core 4 remains stable during the experiment. At the same time, a limiter is set on the movement path of the clamp 3. Based on the mechanical limit principle, by limiting the separation of the two clamps, the structural stability of the clamp 3 during movement and testing is further guaranteed, preventing the core 4 from being displaced or falling off due to the looseness of the clamp, which affects the experimental results.

[0035] After completing the experiment using the acidizing fracturing fluid performance testing device, the method for testing the fracturing fluid performance is as follows: Permeability test: After the experiment, the core 4 is fixed and the professional permeability measuring instrument is sealed and connected to the liquid inlet system.

[0036] The control system is used to adjust the liquid inlet system, and gas (such as nitrogen) or liquid (such as simulated formation water) is injected into the core 4 according to the preset flow rate and pressure. The data acquisition module synchronously monitors the pressure and flow changes and transmits the data to the control unit.

[0037] According to Darcy's law, combined with the measured inlet and outlet pressure difference, flow rate and core 4 size, the permeability of core 4 is calculated using the supporting software. Multiple measurements can be taken to get the average value, accurately reflecting the impact of acid fracturing fluid on permeability.

[0038] Residue content analysis: Take out the core 4 and put it into the filtering device, select a suitable solvent (petroleum ether or deionized water, etc.) to wash the surface and pores of the core 4, and collect the filtrate.

[0039] Use vacuum filtration or centrifugation to separate the filtrate to obtain the residue, accurately weigh the residue with a high-precision balance, and record the total volume of the solvent.

[0040] Calculating the ratio of the residue mass to the total volume of the solvent, i.e., the residue content of the fracturing fluid in the core 4, helps to assess the risk of formation blockage and optimize the formulation.

[0041] Rheological properties determination: Take an appropriate amount of post-experiment fracturing fluid sample from the fluid inlet system or experimental container and transfer it to the high-precision rheometer test unit in a standardized manner.

[0042] The rheological properties of the sample are measured at different temperatures and shear rates using a rheometer, rheological curves are drawn, and the control system collects and stores data in real time.

[0043] Analyze the rheological curve, obtain rheological parameters such as plastic viscosity and yield stress, understand the rheological changes after the acid fracturing fluid interacts with the core 4, and guide the optimization of construction parameters.

[0044] Chemical composition change detection: Use high performance liquid chromatography, gas chromatography and other technologies to accurately process fracturing fluid samples before and after the experiment, inject them into the chromatograph to separate components and detect changes in content.

[0045] By comparing the chromatograms of the samples before and after, we can find out the changes in key chemical components (such as acid concentration and additive content). The control system assists in recording and analyzing and generates reports to provide a basis for studying the reaction mechanism and adjusting the formula.

[0046] Through these comprehensive tests, we can fully understand the performance changes of acid fracturing fluid after the experiment, and provide reliable data for the optimized application of acid fracturing technology.

[0047] In another embodiment, in the acid fracturing fluid performance testing device, an opening is provided in the center of the top of the clamp 3, the contact parts of the two clamps are overlapped, a seal is provided at the overlap of the two clamps, and a support block 301 is provided at the bottom of each of the two clamps. Both support blocks 301 are placed on the bottom of the mounting tube 2 to stably support the two clamps.

[0048] The clamp 3 is the key to ensure the stability of the core 4. The clamp 3 is composed of two symmetrical hollow semi-cylindrical clamps. This design can reduce the overall weight and facilitate operation and installation; secondly, it can fit the outer surface of the core 4, increase the contact area, and improve the clamping stability. The clamp 3 is placed vertically in the installation tube 2, with an opening in the center of the top, which is convenient for the subsequent liquid inlet system to accurately inject liquid into the core 4. A seal is provided at the overlap of the two clamping parts, and the seal is made of high temperature resistant and corrosion resistant fluororubber (fluororubber contains fluorine atoms and has excellent high temperature resistance, oil resistance and chemical corrosion resistance. During the injection of acid fracturing fluid, this high-performance seal can effectively prevent the liquid from leaking from the overlap of the clamping parts, prevent the liquid from corroding the electronic components, mechanical structures and other parts inside the device, ensure the sealing of the experimental environment, reduce errors, extend the service life of the device, and at the same time ensure that the experimental data is not interfered by external factors and is true and reliable). There is a support block 301 at the bottom of each of the two clamping parts, and the support block 301 is placed on the bottom of the mounting tube 2 to form a stable support structure, reduce the risk of shaking and displacement of the clamp 3 during operation, and ensure the smooth progress of the experiment. The clamp itself is forged from high-strength alloy steel (high-strength alloy steel is made by adding alloy elements such as manganese, silicon, and chromium to ordinary carbon steel. After quenching, tempering and other heat treatments, it has excellent properties such as high strength, high toughness, wear resistance, and corrosion resistance. The wear resistance is better after surface hardening treatment, and it is not easy to wear and deform due to frequent contact and force during long-term use, affecting the clamping. The clamp made of high-strength alloy steel can firmly clamp various cores 4 of different hardness and textures, adapt to diverse experimental needs, and ensure that the core 4 will not be broken or displaced due to the clamping force during the experiment, providing strong support for the smooth progress of the experiment).

[0049] In another embodiment, the acid fracturing fluid performance testing device further comprises: The liquid inlet hood 9 is composed of two symmetrical semi-cylindrical hoods, which are vertically arranged on the top of the clamp 3 and are made of transparent corrosion-resistant material. The two hoods are respectively fixed on the two clamps, the interiors of the two hoods are opposite to the open openings, the contact parts of the two hoods overlap, and a seal is provided at the overlap of the two hoods. A liquid inlet port and a liquid discharge port are provided on the liquid inlet hood 9, and a sealing cover is provided on the top of the liquid inlet hood 9, which is fixed on one of the two hoods.

[0050] The use principle of the liquid inlet cover 9: Structural sealing principle: The liquid inlet cover 9 is composed of two symmetrical semi-cylindrical cover bodies, and the contact parts of the two cover bodies overlap, and a seal is provided at the overlap. This structural design and the use of the seal can effectively prevent the acid fracturing fluid from leaking during the injection process. When the two cover bodies are tightly connected by the seal, a relatively closed space is formed, so that the acid fracturing fluid can only enter from the liquid inlet and be discharged from the liquid outlet, which ensures the controllability of the liquid flow during the experiment and avoids the harm of liquid leakage to the experimental environment and personnel.

[0051] Liquid injection and discharge principle: The liquid inlet cover 9 is provided with a liquid inlet and a liquid discharge port. At the beginning of the experiment, the liquid supply device injects the acid fracturing fluid into the liquid inlet cover 9 through the liquid inlet. The design of the liquid inlet ensures that the liquid can enter the liquid inlet cover 9 at a suitable flow rate and pressure, and then act on the core 4. The liquid discharge port is used to discharge the waste liquid or excess liquid generated during the experiment. By reasonably controlling the switch of the liquid inlet and the liquid discharge port and the flow rate, the liquid amount and pressure in the liquid inlet cover 9 can be accurately adjusted to meet the needs of different experimental conditions.

[0052] Observation and monitoring principles: The liquid inlet cover 9 is made of a transparent corrosion-resistant material, which enables the operator to visually observe the reaction between the internal acid fracturing fluid and the core 4. During the experiment, the color of the liquid, the change of the liquid level, and the state of the core 4 under the action of the liquid can be monitored in real time. This observed information helps to timely discover possible problems during the experiment, such as liquid blockage, abnormal reaction of the core 4, etc., and adjust the experimental parameters according to the situation, thereby ensuring the smooth progress of the experiment and the accuracy of the experimental results.

[0053] Working principle with gripper 3: The liquid inlet cover 9 is vertically arranged on the top of the clamp 3, and the two cover bodies are respectively fixed on the two clamps, and the interiors of the two cover bodies are opposite to the opening in the center of the top of the clamp 3. After the clamp 3 fixes the core 4, the liquid inlet cover 9 and the clamp 3 form a whole, so that the acid fracturing fluid injected from the liquid inlet can directly act on the core 4. When the pushing device 6 drives the clamp 3 to move, the liquid inlet cover 9 also moves synchronously, which will not affect the relative position relationship between it and the clamp 3, ensuring the continuity and stability of liquid injection and core 4 testing during the experiment.

[0054] Capping and sealing principle: A sealing cover is provided on the top of the liquid inlet cover 9, and the sealing cover is fixed on one of the two cover bodies. During the experiment, the sealing cover can further enhance the sealing performance of the liquid inlet cover 9 to prevent the liquid from overflowing from the top. The design of the sealing cover allows it to be easily opened and closed when the core 4 needs to be replaced or the inside of the liquid inlet cover 9 needs to be cleaned and maintained, which provides convenience for the experimental operation. At the same time, the sealing performance of the sealing cover also ensures the stability of the liquid pressure during the experiment, which is conducive to improving the reliability of the experimental results. In another embodiment, the acid fracturing fluid performance test device also includes: Multiple driving devices 5 are arranged between the outer wall of each clamping piece and the inner wall of the mounting tube 2, the fixed end of each driving device 5 is fixed on the inner wall of the mounting tube 2, and a linear displacement sensor is installed inside the movable end of each driving device 5 near the end position, and the movable end of each driving device 5 selectively contacts with the corresponding clamping piece; multiple driving devices 5 are arranged between the clamp 3 and the mounting tube 2, and there are multiple driving devices 5 distributed between the outer wall of each clamping piece and the inner wall of the mounting tube 2, the fixed end of the driving device 5 is fixed on the inner wall of the mounting tube 2, and a linear displacement sensor is installed inside the movable end near the end position, with an accuracy of micron level, just like a "precision ruler", which converts the results of mechanical calculations into electrical signals according to the principles of electromagnetic induction, photoelectric effect, etc., accurately senses the telescopic state of the driving device 5, and feeds back the stroke information of the clamping piece in real time, so as to accurately control the clamping The holding force provides key data to ensure the accuracy and reliability of the experimental data; the driving device 5 is commonly hydraulic, pneumatic drive, etc. The present invention gives priority to the hydraulic driving device 5, which is composed of a hydraulic pump, a hydraulic cylinder, a hydraulic control valve and an oil tank, etc., and can provide a strong and stable thrust to meet the clamping force requirements. The clamping force can be accurately adjusted by adjusting the pressure of the hydraulic system (the hydraulic driving device 5 utilizes the incompressible property of the liquid to convert mechanical energy into hydraulic energy through a hydraulic pump, which is stored in the oil tank, and then the hydraulic control valve accurately regulates the flow direction and pressure of the hydraulic oil to drive the hydraulic cylinder piston to move, thereby pushing the clamp 3. This driving method can provide a large clamping force in an instant, and can be finely adjusted according to the experimental requirements to ensure that the core 4 is always stably clamped during the experiment. Whether it is a long-term immersion experiment or a high-intensity pressure test, the accuracy and reliability of the experimental data can be guaranteed).

[0055] Multiple pressure sensors, at least one pressure sensor is respectively provided on the active end of each driving device 5 and the part in contact with the corresponding clamping piece; at least one pressure sensor is provided at the contact part between the active end of the driving device 5 and the clamping piece, and the pressure sensor has an accuracy of ±0.5% FS. It converts pressure into an electrical signal based on piezoresistance, piezoelectric effect, etc., accurately measures the clamping force, and ensures that it is stable at the required level. Multiple driving devices 5 cooperate with linear displacement and pressure sensors to accurately monitor and adjust the clamping force in real time to avoid the influence of clamping force fluctuation on the experimental results. For example, in the experiment of studying the effect of acid fracturing fluid on the permeability of core 4, stabilizing the clamping force can protect the microstructure of core 4 from additional interference and obtain accurate permeability data.

[0056] Control unit; A data acquisition module, which is connected to the control unit and each pressure sensor, each drive device 5, each linear displacement sensor, and each push device 6, and is used to collect data transmitted by each pressure sensor, each drive device 5, each linear displacement sensor, and each push device 6, and transmit the data to the control unit; The driving module is connected to the control unit, the driving device 5 and the pushing device 6 , and is used to obtain data transmitted by the control unit and provide driving signals for the driving device 5 and the pushing device 6 .

[0057] The control system includes a control unit, which uses a high-performance industrial control computer with powerful data processing capabilities and high-speed communication interfaces, and is equipped with professional control software to quickly analyze and process sensor data and send precise instructions to the drive module according to the preset algorithm; the data acquisition module is connected to the control unit, each pressure sensor, drive device 5, linear displacement sensor, and push device 6 to collect their data and transmit them to the control unit; the drive module is connected to the control unit, drive device 5 and push device 6 to obtain control unit data and provide drive signals for the latter two. Each module works together to accurately control device components and collect feedback data in real time to ensure efficient and stable operation of the experiment.

[0058] The clamping force adjustment principle is as follows: The control system adopts a closed-loop control strategy, with the pressure sensor as a feedback element to monitor the clamping force between the clamp 3 and the core 4 in real time. The linear displacement sensor provides the position information of the drive device 5. The data of these two sensors together constitute the feedback signal of the control system. The control system compares the received actual value of the clamping force with the preset target value and calculates the deviation value. Then, based on the deviation value and the current position information of the active end of the drive device 5, the displacement that needs to be adjusted at the active end of the drive device 5 is calculated through a pre-set control algorithm (such as the PID control algorithm, i.e., the proportional-integral-differential control algorithm), thereby achieving precise control of the clamping force.

[0059] For example, the proportional (P) link in the PID control algorithm directly produces a control effect according to the size of the deviation, so that the active end of the drive device 5 moves in the direction of reducing the deviation; the integral (I) link integrates the deviation to eliminate the steady-state error of the system and ensure that the clamping force can be stabilized near the target value; the differential (D) link predicts the trend in advance according to the rate of change of the deviation, fine-tunes the action of the active end of the drive device 5, prevents over-adjustment, and improves the response speed and stability of the system.

[0060] Adjustment process when the clamping force is less than the target value: 1. When the high-precision pressure sensor detects in real time that the clamping force is less than the set target value, it immediately transmits the data to the data acquisition module of the control system. The data acquisition module quickly receives and converts the data and transmits it to the control unit.

[0061] 2. After receiving the data, the control unit instantly activates the built-in control algorithm, and based on the precise difference between the real-time clamping force and the target value, quickly calculates the adjustment parameters required by the drive device 5 through complex calculation logic, and then sends precise instructions to the drive module.

[0062] 3. After receiving the instruction, the driving module drives the corresponding driving device 5 to operate.

[0063] 4. During the adjustment of the drive device 5, the linear displacement sensor simultaneously uses the high-precision measurement function to monitor the expansion and contraction dynamics of the drive device 5 in real time, and feeds back the position change information to the control unit at a high frequency. The control unit integrates the clamping force data fed back by the pressure sensor in real time, and uses the closed-loop control principle to determine whether the clamping force has returned to the target value range. Once it is determined that the clamping force has not reached the target, the above-mentioned fine adjustment process is immediately repeated, and the cycle continues until the clamping force is firmly within the target range.

[0064] For example, when the experiment requires a clamping force of 1000N, the pressure sensor measures the current clamping force in real time. If the measured value is 800N, the deviation is 200N. Based on the position information of the linear displacement sensor and the PID algorithm, the control system calculates that the active end of the drive device 5 needs to be extended by a certain distance (such as 5mm) to increase the clamping force. After the drive device 5 extends its active end by 5mm, the pressure sensor measures the clamping force again. If it still does not reach 1000N, it continues to adjust until the clamping force stabilizes near the target value.

[0065] Adjustment process when the clamping force is greater than the target value: 1. When the high-precision pressure sensor detects in real time that the clamping force exceeds the set target value, it immediately transmits the data to the data acquisition module of the control system. The data acquisition module quickly captures and converts the data and transmits it to the control unit.

[0066] 2. After receiving the data, the control unit instantly activates the built-in control algorithm, and quickly calculates the adjustment parameters required for the drive device 5 based on the precise difference between the real-time clamping force and the target value, and then issues precise instructions to the drive module.

[0067] 3. After receiving the instruction, the driving module drives the corresponding driving device 5 to operate.

[0068] 4. When the drive device 5 is adjusted, the linear displacement sensor synchronously monitors its extension and contraction state in real time with high-precision measurement technology, and feeds back position information to the control unit at a high frequency. The control unit combines the feedback data from the pressure sensor and uses a closed-loop control strategy to determine whether the clamping force has returned to the target value range. If it does not meet the target, the above steps are repeated until the clamping force is stabilized within the target range.

[0069] For example, when the clamping force is set to 600N in the experiment, the pressure sensor monitors the current clamping force in real time. At this time, the measured value is 800N, and the deviation is 200N (800N - 600N). The control system combines the position information fed back by the linear displacement sensor and uses the PID algorithm to quickly calculate that the active end of the drive device 5 needs to retract a certain distance, assuming it is 4mm, to reduce the clamping force. After the drive device 5 receives the instruction to accurately retract its active end by 4mm, the pressure sensor immediately measures the clamping force again. If the measured value is still higher than 600N, the above process is repeated and continuously adjusted according to the new data until the clamping force stabilizes at around 600N, ensuring that the experimental data is not affected by the fluctuation of the clamping force and can accurately reflect the performance of the acid fracturing fluid.

[0070] The working principle of the acid fracturing fluid performance test device in this scheme: Movement principle of the clamp 3: Multiple pushers 6 are fixed at the bottom of the installation tube 2, and the support plate 7 at the top of the pusher end contacts the bottom of the clamp 3. When the pusher 6 is working, it transmits power to the support plate 7, causing it to move vertically, thereby driving the clamp 3 to move in the direction of entering or leaving the installation tube 2, meeting the requirements for the position of the clamp 3 in different stages of core 4 loading and unloading and testing.

[0071] Principle of clamping force monitoring and control: Multiple drive devices 5 are distributed between the clamping part and the mounting tube 2, and the fixed end is fixed to the inner wall of the mounting tube 2. The linear displacement sensor near the end position inside the movable end can accurately monitor the telescopic state of the drive device 5 and obtain the stroke information of the clamping part; the pressure sensor at the contact part between the movable end and the clamping part measures the clamping force in real time. The control unit, data acquisition module and drive module work together. The data acquisition module collects sensor data and transmits it to the control unit. The control unit compares the actual value of the clamping force with the preset target value. After calculating the deviation, the adjustment displacement of the movable end of the drive device 5 is calculated through a preset control algorithm (such as a PID control algorithm). The drive module drives the drive device 5 to move according to the instructions of the control unit to achieve precise adjustment of the clamping force, ensure the stability of the clamping force, and avoid its fluctuation affecting the experimental results.

[0072] Data acquisition and transmission principle: The data acquisition module is responsible for collecting data transmitted by each pressure sensor, drive device 5, linear displacement sensor and push device 6, and transmitting these data to the control unit. The control unit analyzes and processes the received data and sends instructions to the drive module according to the preset algorithm. The drive module provides drive signals to the drive device 5 and the push device 6 according to the instructions of the control unit, thereby realizing precise control of each component of the device and ensuring efficient and stable operation of the experiment.

[0073] Method of using the acid fracturing fluid performance test device in this scheme: Preparation stage: separate the multiple driving devices 5 from the clamp 3, operate the pushing device 6 through the control system, and raise the support plate 7 to a suitable height to leave space for placing the clamp 3 and the core 4.

[0074] During the installation phase of the core 4, the core 4 is placed in the clamp 3 composed of two symmetrical hollow semi-cylindrical clamps to ensure the correct position. The clamp 3 and the core 4 are then placed as a whole on the support plate 7. The pushing device 6 then drives the support plate 7 to descend and limits the separation of the two clamps through the limiter. After the clamp 3 is placed on the bottom of the installation tube 2 through the bottom support block 301, the support plate 7 continues to descend and separates from the clamp 3.

[0075] Experimental preparation stage: The clamping force is preset according to the experimental requirements. The control unit calculates the force that the driving device 5 needs to output based on the data fed back by the linear displacement sensor and the pressure sensor. The driving device 5 is actuated to clamp the clamp 3.

[0076] Experimental stage: Start the fluid inlet system to inject acid fracturing fluid into the core 4 for experiment. During the experiment, the data acquisition module monitors various parameters of the device in real time, and the control system automatically adjusts according to the preset algorithm and experimental requirements, such as adjusting the output of the drive device 5 according to the change of the clamping force to ensure the stable progress of the experiment.

[0077] End of the experiment: stop feeding liquid, close the valve, and disconnect the liquid supply device. Separate the drive device 5 from the clamp 3, operate the push device 6 to raise the support plate 7 and the clamp 3, and use the limiter to prevent the clamp 3 from being separated too much. After rising to a suitable height, take out the core 4 and the clamp 3. Finally, clean the device, check the status of each component, and turn off the power supply of the control system.

[0078] In another embodiment, in the acid fracturing fluid performance testing device, the multiple driving devices 5 include multiple pairs of driving devices 5, and the multiple pairs of driving devices 5 are evenly spaced along the circumferential direction of the clamp 3, and each pair of drivers is spaced along the vertical direction and symmetrically arranged.

[0079] In terms of clamping force distribution, this layout ensures that the clamping force can act evenly and omnidirectionally on the clamp 3. Multiple pairs of driving devices 5 exert force from all angles in the circumferential direction at the same time, and with reasonable intervals in the vertical direction, the clamping force is progressive layer by layer and closely fits the surface of the core 4, which greatly enhances the stability of clamping, effectively avoids excessive or insufficient force on the core 4 due to uneven clamping, and ensures that the core 4 is always in an ideal fixed state during the experiment, laying a solid foundation for obtaining accurate experimental data.

[0080] In another embodiment, in the acid fracturing fluid performance testing device, the stopper comprises: The first limit ring 8 is in a circular shape and is fixed on the outer edge of each support plate 7 and is located below each drive device 5; when each support plate 7 is respectively located below the corresponding clamping member and is separated from the corresponding clamping member by a preset distance, the height of the first limit ring 8 is lower than the height of the bottom of the clamp 3; when the top of each support plate 7 is flush with or fits the bottom of the clamp 3, the inner side wall of the first limit ring 8 is in contact with or has a gap with the outer side wall of the lower part of the clamp 3, and the first limit ring 8 is separated from each drive device 5 by a preset distance; the movable end of each drive device 5 can be retracted to not be opposite to the first limit ring 8; the control system controls the drive device 5 to separate the drive device 5 from the clamp 3, and then operates the pushing device 6 through the control system to push the clamp 3 up or down, and at the same time, the first limit ring 8 rises or falls with the support plate 7 to assist in preventing the clamp 3 from being excessively separated. During the ascent or descent of the clamp 3, since the movable end of each driving device 5 is contracted to be not opposite to the first limiting ring 8, each driving device 5 will not affect the ascent or descent of the first limiting ring 8, and the clamp 3 and the core 4 can be raised to a higher position during the ascent, which makes it easier to take out the clamp 3 and the core 4.

[0081] The inner wall of the first limiting ring 8 and the outer wall of the lower part of the clamp 3 are designed to be in contact or have a gap, the core purpose of which is to adapt to different operating stages of the device without causing negative impact on the clamping force applied by the drive device 5.

[0082] During the loading and unloading stage of the core 4, the first limit ring 8 is usually in contact with the outer side wall of the lower part of the clamp 3. When the core 4 and the clamp 3 are placed at the bottom of the installation tube 2, or taken out of the installation tube 2, since the first limit ring 8 is fixed on the support plate 7, as the support plate 7 rises and falls, it fits tightly against the lower outer side wall of the clamp 3, providing key auxiliary support and precise guidance for the clamp 3. On the one hand, this can effectively resist possible interference from external collisions, shaking, etc., prevent the clamp 3 from excessive displacement or even tipping, and ensure that the clamp 3 is accurately returned to its original position; on the other hand, this contact design does not affect the subsequent work flow of the drive device 5, because the drive device 5 has not been started at this stage, and there is no problem of mutual interference between the two. Instead, it lays the foundation for the drive device 5 to smoothly and accurately apply clamping force to the clamp 3 in the future, ensuring the smooth connection of the experimental process.

[0083] Entering the experimental stage, the drive device 5 needs to accurately apply a clamping force to the clamp 3 to fix the core 4. At this time, the first limit ring 8 and the lower outer wall of the clamp 3 are switched to a gap state. This design cleverly avoids any unnecessary interference or friction resistance caused by the first limit ring 8 on the clamp 3. When the drive device 5 pushes the clamp 3, the clamp 3 can freely adjust its position completely according to the precise thrust output by the drive device 5, ensuring that the clamping force acts evenly and stably on the core 4. If the first limit ring 8 is still in contact with the clamp 3 at this time, even a small friction force is likely to hinder the clamp 3 from changing flexibly according to the experimental requirements, thereby destroying the uniform distribution of the clamping force and ultimately interfering with the accurate acquisition of experimental data.

[0084] The first stop ring 8 is annular and fixed on the support plate 7 and is located below the drive device 5. When the support plate 7 is below the clamp 3, the height of the first stop ring 8 is lower than the height of the bottom of the clamp 3; when the top of the support plate 7 is flush with or in contact with the bottom of the clamp 3, the inner side wall of the first stop ring 8 is in contact with or has a gap with the outer side wall of the lower part of the clamp 3, and is separated from the drive device 5 by a preset distance. It has multiple protection functions during the operation of the device, assisting in positioning when loading and unloading the core 4, preventing the clamp 3 from being excessively separated, and not interfering with the operation of the drive device 5. The first stop ring 8 is generally made of high-strength aluminum alloy (lightweight and has a certain rigidity, and is not easy to be deformed and damaged when frequently participating in the auxiliary operation of loading and unloading the core 4. The first stop ring 8 made of high-strength aluminum alloy can always maintain its own shape and structure stability during repeated loading and unloading of the core 4, reliably assist the clamp 3 to complete the positioning and homing action, ensure the repeatability and stability of the experimental operation, and provide guarantee for the comparability of the experimental data).

[0085] The second limiting ring 10 is annular and fixed on the mounting tube 2 . The clamp 3 is located inside the second limiting ring 10 . There is a gap between the inner wall of the second limiting ring 10 and the outer wall of the upper portion of the clamp 3 .

[0086] During the experiment, the second limit ring 10 provides stable lateral support for the clamp 3. Even if a certain impact force is generated when injecting acid fracturing fluid, or due to a slight vibration deviation of the driving device 5, the clamp 3 can maintain a vertical and stable posture by means of the clearance with the second limit ring 10 without tilting or offset, ensuring that the clamp 3 has a consistent clamping accuracy for the core 4, so that the experimental data is not affected by the shaking of the clamp 3.

[0087] The second limit ring 10 plays an indispensable role in the process of the clamp 3 rising or falling. When the core 4 needs to be taken out and the pushing device 6 drives the clamp 3 to rise, due to the complexity of the operating environment, such as the vibration of surrounding equipment and the operator's unintentional touch, the clamp 3 may be disturbed by external forces, thereby generating the risk of dispersion and deviation from the original vertical trajectory. At this time, the second limit ring 10 uses the gap between it and the upper outer wall of the clamp 3 to give appropriate constraints from the side, and effectively limits its excessive lateral displacement without hindering the normal rising action of the clamp 3, ensuring that the two clamps are always tightly closed, preventing the core 4 from accidentally slipping due to the dispersion of the clamp 3, and ensuring the safety of the core 4 and the operator. Similarly, when the core 4 is installed and the clamp 3 is lowered back to its position, uncertain factors in the environment may still affect the smooth landing of the clamp 3. The second limit ring 10 can assist the clamp 3 to accurately align with the installation position, avoiding the dispersion of the clamp 3 due to uneven descending speed or external collision, ensuring that each installation can be completed smoothly and efficiently, and providing a strong guarantee for the continuity of the entire experimental process.

[0088] From the perspective of long-term use, the existence of the gap cleverly resolves the friction and wear problems between the clamp 3 and the second limit ring 10 that may be caused by factors such as frequent operation and temperature changes. On the one hand, it prolongs the service life of both and reduces maintenance costs; on the other hand, it continuously guarantees the accuracy of the limit function, providing a solid backing for the repeatability and reliability of the experiment, and each experiment is as accurate as the first operation.

[0089] The working principle of the acid fracturing fluid performance test device in this scheme: The movement and limit principle of the clamp 3: A plurality of pushers 6 are fixed to the bottom of the installation tube 2, and the support plate 7 at the top of the pusher end contacts the bottom of the clamp 3. When the pushers 6 are working, the clamp 3 is driven to move in the direction of entering or leaving the installation tube 2 through the support plate 7. In this process, the limiter plays a key role in limiting and stabilizing.

[0090] The first limiting ring 8 is fixed to the outer edge of the support plate 7 and is located below the driving device 5. During the loading and unloading stage of the core 4, when the support plate 7 rises so that the top is flush with or fits the bottom of the clamp 3, the inner side wall of the first limiting ring 8 contacts the lower outer side wall of the clamp 3, providing auxiliary support and guidance for the clamp 3 to prevent it from excessive deviation or tipping, and will not affect the subsequent operation of the driving device 5; during the experimental stage, when the driving device 5 is working, the first limiting ring 8 maintains a gap with the lower outer side wall of the clamp 3 to avoid interference with the clamp 3 and ensure uniform and stable clamping force.

[0091] The second limit ring 10 is fixed on the mounting tube 2, and the clamp 3 is located therein. There is a gap between its inner wall and the outer wall of the upper part of the clamp 3. During the experiment, when the acid fracturing fluid is injected to generate impact force, or the driving device 5 is working to generate vibration, the second limit ring 10 provides stable lateral support for the clamp 3 to prevent the clamp 3 from tilting or deflecting; during the rise or fall of the clamp 3, the second limit ring 10 limits its lateral displacement to ensure the safety of the core 4 and the continuity of the experimental process.

[0092] Clamping force monitoring and control principle: A plurality of driving devices 5 are distributed between the clamping member and the mounting tube 2, and the fixed end thereof is fixed to the inner wall of the mounting tube 2. The linear displacement sensor located near the end position inside the movable end can accurately monitor the telescopic state of the driving device 5 and obtain the stroke information of the clamping member; the pressure sensor at the contact part between the movable end and the clamping member can measure the clamping force in real time. The control unit, the data acquisition module and the driving module work together. The data acquisition module collects the sensor data and transmits it to the control unit. The control unit compares the actual value of the clamping force with the preset target value. After calculating the deviation, the adjustment displacement of the movable end of the driving device 5 is calculated through a preset control algorithm (such as a PID control algorithm). The driving module drives the driving device 5 to move according to the instruction of the control unit to achieve precise adjustment of the clamping force, ensure the stability of the clamping force, and avoid its fluctuation affecting the experimental results.

[0093] Data collection and transmission principle: The data acquisition module is responsible for collecting data transmitted by each pressure sensor, driving device 5, linear displacement sensor and pushing device 6, and transmitting these data to the control unit. The control unit analyzes and processes the received data and sends instructions to the driving module according to the preset algorithm. The driving module provides driving signals to the driving device 5 and the pushing device 6 according to the instructions of the control unit, thereby realizing precise control of each component of the device and ensuring efficient and stable operation of the experiment.

[0094] Method of using the acid fracturing fluid performance test device in this scheme: Preparation stage: The control system controls the driving device 5 so that its movable end contracts and separates from the clamp 3 , while ensuring that the movable end of the driving device 5 contracts to not be opposite to the first limiting ring 8 to avoid interference.

[0095] The pusher 6 is operated to raise the support plate 7 to a suitable height to create enough space for placing the clamp 3 and the core 4. At this time, the relative position of the second limit ring 10 and the clamp 3 is observed to confirm that there is enough space for subsequent operations.

[0096] Core 4 Installation Phase: The core 4 is carefully placed in the holder 3 consisting of two symmetrical hollow semi-cylindrical holders, ensuring that the position is accurate.

[0097] Place the clamp 3 and the core 4 as a whole on the support plate 7 stably. At this time, the inner wall of the first limiting ring 8 contacts the outer wall of the lower part of the clamp 3, playing an auxiliary supporting and guiding role to ensure the stability of the placement process. At the same time, pay attention to the position of the clamp 3 in the second limiting ring 10 to ensure that it is in the center position to ensure smooth subsequent movement.

[0098] The push device 6 is operated to drive the support plate 7 to slowly descend until the clamp 3 is stably placed on the bottom of the installation tube 2 through the bottom support block 301. The support plate 7 continues to descend until it is separated from the clamp 3 and stops descending when the height of the first limit ring 8 is lower than the bottom height of the clamp 3. During this process, the second limit ring 10 limits the lateral shaking of the clamp 3 to ensure the stability of placement.

[0099] Experimental preparation stage: According to the specific requirements of the experiment, the clamping force value is preset in the control system.

[0100] The control unit obtains the real-time feedback data from the linear displacement sensor and the pressure sensor, calculates the force that the drive device 5 needs to output according to the preset algorithm, and then controls the movable end of the drive device 5 to extend and retract to clamp the clamp 3. In this process, the first limit ring 8 and the drive device 5 do not interfere with each other, and the second limit ring 10 continues to provide lateral stable support for the clamp 3.

[0101] Experimental stage: The fluid injection system was started to inject acid fracturing fluid into the core 4 according to the set parameters, and the experiment officially began.

[0102] During the experiment, the data acquisition module continuously monitors the key parameters of the device in real time, including the clamping force, the position of the active end of the drive device 5, etc.

[0103] The control system automatically adjusts according to the preset algorithm and the actual experimental situation. For example, when the pressure sensor detects that the clamping force changes due to the core 4 under the action of the acid fracturing fluid, the control system timely adjusts the output of the drive device 5 according to the feedback data to maintain the stability of the clamping force. During this period, the first limit ring 8 does not affect the operation of the drive device 5, and the second limit ring 10 continues to stabilize the position of the clamp 3 to resist the impact of the injection of the acid fracturing fluid and the vibration of the drive device 5.

[0104] End of the experiment: After the experiment is completed, first stop the liquid inlet operation, close the valve of the liquid inlet system, and disconnect the liquid supply device.

[0105] The control system controls the driving device 5 again to separate it from the clamp 3, and at the same time operates the pushing device 6 to push the support plate 7 and the clamp 3 upward. During the upward process, the first limit ring 8 rises with the support plate 7 to help prevent the clamp 3 from being excessively separated, and the second limit ring 10 continues to limit the lateral displacement of the clamp 3 to ensure a smooth upward process.

[0106] When the holder 3 rises to a suitable height for easy operation, it stops rising and the core 4 and the holder 3 are carefully taken out. In another embodiment, in the acid fracturing fluid performance testing device, the mounting tube 2 is U-shaped; The acid fracturing fluid performance testing device also includes: The bracket 1 is U-shaped, and the mounting tube 2 is located inside the bracket 1 and is rotatably connected to the bracket 1. The two vertical parts of the mounting tube 2 are rotatably connected to the two vertical parts of the bracket 1 through the rotating shaft 11. One end of each rotating shaft 11 is fixedly connected to the vertical part of the mounting tube 2 corresponding to it, and the other end is rotatably connected to the vertical part of the bracket 1 corresponding to it. One of the two rotating shafts 11 rotates under the drive of the power device 12; the power device 12 is connected to the control unit, the data acquisition module, and the drive module. When studying the erosion effect of the acid fracturing fluid on the core 4 at different formation fracture angles, the mounting tube 2 is rotated to flexibly adjust the angle of the core 4, simulate the real formation environment, and collect more practical data for the optimization of the acid fracturing technology, broadening the depth and breadth of the experiment.

[0107] In terms of space utilization, the U-shaped design realizes the compact nesting of the bracket 1 and the mounting tube 2. In the limited space of the laboratory, a more spacious operating space is reserved for operators, which is convenient for them to load and unload the core 4 and connect pipelines, etc., reducing the risk of misoperation caused by cramped space and improving experimental efficiency.

[0108] The power device 12 is connected to the control unit, data acquisition module, and drive module, and plays a key role in the entire adjustment process. The data acquisition module collects the operating parameters of the power device 12 in real time, such as power output power, speed, etc., and transmits this information to the control unit. The control unit comprehensively determines whether the power device 12 is in the best working state based on these data and the feedback from the linear displacement sensor and the pressure sensor. If an abnormality is found, the power distribution can be adjusted in time or an alarm can be issued to ensure the stable operation of the entire device.

[0109] The angle adjustment function is enhanced by this connection method. When the power device 12 drives the rotating shaft 11 to rotate, the mounting tube 2 can achieve smooth and accurate angle changes. Compared with the traditional connection, the resistance during the rotation process is smaller and the precision is higher. The operator can quickly and accurately adjust the angle of the core 4 according to the experimental requirements, simulate the complex formation fracture environment, explore the performance of the acid fracturing fluid under different working conditions, and broaden the boundaries of experimental research.

[0110] In another embodiment, in the acid fracturing fluid performance testing device, the inner diameter of the first limiting ring 8 gradually decreases from top to bottom.

[0111] This gradual inner diameter plays an excellent guiding role in the loading and unloading of the core 4. When the support plate 7 drives the clamp 3 to descend and return to its position, the lower part of the clamp 3 can slide smoothly along the first limit ring 8 with a gradually decreasing inner diameter and accurately position, effectively preventing the subsequent uneven clamping force caused by placement deviation, greatly shortening the preparation time for the installation of the core 4 and improving the continuity of the experimental process.

[0112] During the experiment, even if the clamp 3 is slightly displaced due to sudden factors such as external vibrations, the first limit ring 8 with a gradually changing inner diameter can use its special shape to automatically fine-tune and correct the clamp 3, pull the clamp 3 back to the ideal position, and maintain the overall stability of the device.

[0113] In another embodiment, in the acid fracturing fluid performance testing device, there are four pairs of driving devices 5, and the movable ends of two pairs of driving devices 5 among the four pairs of driving devices 5 can respectively contact the middle of the corresponding clamping members.

[0114] For the slender core 4, this distribution mode of the driving device 5 is particularly critical. Two pairs of driving devices 5 act on the middle of the clamping piece, which can accurately apply concentrated and appropriate clamping force to the middle of the core 4, avoiding the "bow-shaped" deformation of the core 4 in the length direction due to relying solely on the end clamping. In conjunction with the stabilizing effect of the other two pairs of driving devices 5 on the ends of the clamping piece, the straightness of the slender core 4 in the experiment is fully guaranteed, ensuring that the seepage and reaction process of the acid fracturing fluid inside the core 4 conforms to the actual formation conditions, and enhancing the guiding value of the experimental results for actual engineering.

[0115] When dealing with some special core 4 materials that are highly sensitive to the distribution of clamping force (such as brittle shale core 4), this solution cleverly balances the clamping force through precise coordinated clamping of the middle and ends, prevents the expansion of cracks in the core 4 caused by sudden changes in local clamping force, protects the integrity of the core 4, and provides reliable support for studying the performance changes of special core 4 under the action of acid fracturing fluid.

[0116] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. Acid fracturing fluid performance testing device, characterized in that: include: Install the barrel; The clamp is composed of two symmetrical hollow semi-cylindrical clamping parts and is vertically arranged in the mounting cylinder; A plurality of pushing devices, wherein the fixed ends of the pushing devices are respectively fixed to the bottom of the mounting tube; A plurality of support plates, wherein a support plate is disposed on the top of the push end of each push device, and at least one support plate is disposed under each clamping member; Wherein, the plurality of pushing devices push the plurality of supporting plates to move vertically, so as to drive the clamper to move in the direction of entering the installation tube and leaving the installation tube; Furthermore, a limiting member for limiting the separation of the two clamping members is provided on the moving path of the clamp.

2. The acid fracturing fluid performance testing device according to claim 1, characterized in that: An opening is provided in the center of the top of the clamp, the contact parts of the two clamps overlap, a sealing member is provided at the overlap of the two clamps, a supporting block is provided at the bottom of each of the two clamps, and both supporting blocks are placed on the bottom of the mounting tube to support the two clamps.

3. The acid fracturing fluid performance testing device according to claim 2, characterized in that: Also includes: The liquid inlet hood is composed of two symmetrical semi-cylindrical hoods, which are vertically arranged on the top of the clamp and are made of transparent corrosion-resistant material. The two hoods are respectively fixed on the two clamps, the interiors of the two hoods are opposite to the open mouth, the contact parts of the two hoods are overlapped, and a sealing member is arranged at the overlap of the two hoods. The liquid inlet hood is provided with a liquid inlet port and a liquid discharge port, and a sealing cover is arranged on the top of the liquid inlet hood, and the sealing cover is fixed on one of the two hoods.

4. The acid fracturing fluid performance testing device according to claim 1, characterized in that: Also includes: Multiple driving devices, multiple driving devices are arranged between the outer wall of each clamping member and the inner wall of the mounting tube, the fixed end of each driving device is fixed to the inner wall of the mounting tube, a linear displacement sensor is installed near the end of the movable end of each driving device, and the movable end of each driving device selectively contacts with the corresponding clamping member; A plurality of pressure sensors, wherein at least one pressure sensor is respectively arranged on the movable end of each driving device and at the position in contact with the corresponding clamping member; Control unit; A data acquisition module, which is connected to the control unit and each pressure sensor, each drive device, each linear displacement sensor, and each pushing device, and is used to collect data transmitted by each pressure sensor, each drive device, each linear displacement sensor, and each pushing device, and transmit the data to the control unit; The driving module is connected with the control unit, the driving device and the pushing device, and is used to obtain data transmitted by the control unit and provide driving signals for the driving device and the pushing device.

5. The acid fracturing fluid performance testing device according to claim 4, characterized in that: The multiple driving devices include multiple pairs of driving devices, which are arranged at equal intervals along the circumferential direction of the clamper, and each pair of drivers is spaced apart along the vertical direction and symmetrically arranged.

6. The acid fracturing fluid performance testing device according to claim 4, characterized in that: The limiting member comprises: The first limiting ring is in the shape of a circular ring and is fixed on the outer edge of each supporting plate and is located below each driving device; when each supporting plate is respectively located below the corresponding clamping member and is separated from the corresponding clamping member by a preset distance, the height of the first limiting ring is lower than the height of the bottom of the clamp; when the top of each supporting plate is flush with or in contact with the bottom of the clamp, the inner side wall of the first limiting ring is in contact with or has a gap with the outer side wall of the lower part of the clamp, and the first limiting ring is separated from each driving device by a preset distance; the movable end of each driving device can be retracted to not be opposite to the first limiting ring; The second limiting ring is annular and fixed on the mounting tube. The clamp is located inside the second limiting ring. There is a gap between the inner side wall of the second limiting ring and the outer side wall of the upper part of the clamp.

7. The acid fracturing fluid performance testing device according to claim 4, characterized in that: The mounting tube is U-shaped; The acid fracturing fluid performance testing device also includes: The bracket is U-shaped, the mounting tube is located inside the bracket and is rotatably connected to the bracket, the two vertical parts of the mounting tube are respectively rotatably connected to the two vertical parts of the bracket through a rotating shaft, one end of each rotating shaft is respectively fixedly connected to the vertical part of the mounting tube corresponding thereto, and the other end is respectively rotatably connected to the vertical part of the bracket corresponding thereto, and one of the two rotating shafts rotates under the drive of a power device; the power device is connected to a control unit, a data acquisition module, and a driving module.

8. The acid fracturing fluid performance testing device according to claim 6, characterized in that: The inner diameter of the first limiting ring gradually decreases from top to bottom.

9. The acid fracturing fluid performance testing device according to claim 5, characterized in that: There are four pairs of driving devices, and the movable ends of two pairs of driving devices among the four pairs of driving devices can respectively contact the middle parts of the clamping members corresponding thereto.

Images