Multi-scale proppant transport flat-plate device wall surface electromagnetic control closing stress system

Abstract

The present invention discloses an electromagnetic control closing stress system for the wall surface of a multi-scale proppant transport flat plate device, which includes a flat plate device wall surface for simulating a formation fracture channel; an electromagnetic generating device is disposed around the outside of the flat plate device wall surface, and the electromagnetic generating device is used to generate electromagnetic force to control the flat plate device wall surface and regulate the closing stress of the flat plate device wall surface through the generated electromagnetic force; a stress monitoring module is arranged on the flat plate device wall surface, and the stress monitoring module is used to monitor the stress condition of the flat plate device wall surface in real time and feedback data; a control system for receiving the data fed back by the stress monitoring module, and the control system controls the working state of each electromagnetic coil in the electromagnetic generating device according to preset stress parameters. The present invention can accurately simulate the stress environment under various complex formation conditions, provides a reliable experimental means for in-depth study of the proppant transport law, helps to improve the R & D efficiency and level of oil and gas field fracturing technology, and promotes the development of the oil and gas industry.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation, and particularly to an electromagnetic control closing stress system for the wall surface of a multi-scale proppant transport flat plate device. Background Art

[0002] During the fracturing exploitation process of oil and gas fields, the transport characteristics of proppants have a crucial impact on the fracture conductivity and oil and gas production.

[0003] Traditional proppant transport research devices often have difficulty in accurately simulating and controlling the complex stress conditions in the actual formation. Especially in a large-scale multi-scale experimental environment, how to effectively regulate the closing stress of the flat plate device wall surface to more realistically reflect the formation situation has become a key issue in current research.

[0004] Currently, existing technical means have many deficiencies in terms of the accuracy, flexibility of stress control, and the adaptability to multi-scale proppant transport experiments, and it is difficult to meet the growing R & D needs of oil and gas exploitation technologies. Summary of the Invention

[0005] The purpose of the present invention is to provide an electromagnetic control closing stress system for the wall surface of a multi-scale proppant transport flat plate device to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above purpose, the present invention provides an electromagnetic control closing stress system for the wall surface of a multi-scale proppant transport flat plate device, including:

[0007] The flat plate device wall surface, which is used to simulate the formation fracture channel, and the flat plate device wall surface is made of concrete, a visualization module, and electromagnetic induction material;

[0008] The electromagnetic generating device, which is arranged around the outside of the flat plate device wall surface; the electromagnetic generating device includes a plurality of electromagnetic coils, and the electromagnetic generating device is used to generate electromagnetic force to control the flat plate device wall surface and regulate the closing stress of the flat plate device wall surface through the generated electromagnetic force;

[0009] The stress monitoring module, which is arranged on the flat plate device wall surface, and the stress monitoring module is used to monitor the stress situation of the flat plate device wall surface in real time and feedback data;

[0010] The control system, which is used to receive the data fed back by the stress monitoring module and control the working state of each electromagnetic coil in the electromagnetic generating device according to the preset stress parameters.

[0011] Preferably, the electromagnetic coil is made of a material with high temperature resistance and high conductivity.

[0012] Preferably, the stress monitoring module adopts high-precision strain gauges and / or fiber Bragg grating sensors.

[0013] An operation method of an electromagnetic control closing stress system for the wall surface of a multi-scale proppant transport flat plate device includes the following steps:

[0014] S1. According to the formation stress conditions to be simulated, preset the target closing stress parameters for each area of the wall surface of the flat plate device in the control system;

[0015] S2. Start the electromagnetic generating device, and the control system sends control signals to each electromagnetic coil according to the preset parameters, so that the electromagnetic coil generates an electromagnetic field with corresponding intensity and direction;

[0016] S3. Conduct a proppant transport experiment, use the stress monitoring module to monitor the stress change of the wall surface of the flat plate device in real time, and transmit the monitoring data back to the control system;

[0017] S4. The control system analyzes and processes the data fed back by the stress monitoring module, compares it with the preset stress parameters, and dynamically adjusts the electromagnetic field parameters of each electromagnetic coil in the electromagnetic generating device according to the comparison results to ensure that the closing stress of the wall surface of the flat plate device always remains within the preset range.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] 1. The present invention can accurately simulate the stress environment under various complex formation conditions in a large multi-scale proppant transport flat plate device, providing a reliable experimental means for in-depth study of the proppant transport law, helping to improve the R & D efficiency and level of oil and gas field fracturing technology, and promoting the development of the oil and gas industry.

[0020] 2. The wall surface of the proppant placement and transport device is a simulated real tortuous fracture wall surface with different tortuous structures. By adjusting the fracture width, the proppant placement and transport tests under different sizes can be realized, so as to achieve the effect of multi-scale simulation. By designing a variety of fluid channels with different sizes, the proppant transport behaviors at different geological levels can be simulated, increasing the adaptability and universality of the experimental results.

[0021] 3. Electromagnetic control of the wall surface closing stress, controlling the wall surface stress through electromagnetic coils, adjusting the stability of the proppant during transport, avoiding proppant blockage or deviation, and ensuring the uniform distribution of the proppant in the fluid.

[0022] 4. Real-time monitoring and regulation, the built-in stress monitoring system and feedback control mechanism enable the device to automatically adjust the electromagnetic field parameters according to the real-time stress changes during the experiment, improving the accuracy and stability of the experiment. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic diagram of the wall surface electromagnetic control closed stress system of the multi-scale proppant transport flat plate device of the present invention;

[0025] Figure 2 It is a schematic diagram of the wall surface of the flat plate device of the present invention;

[0026] In the figure: 1. Wall surface of the flat plate device; 2. Electromagnetic generating device; 3. Stress monitoring module; 4. Control system. Detailed implementation manners

[0027] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. The following will refer to the drawings and combine with the embodiments to detail the present invention.

[0028] As Figures 1 to 2 shown, the present invention provides a wall surface electromagnetic control closed stress system for a multi-scale proppant transport flat plate device, including:

[0029] The wall surface 1 of the flat plate device, which is used to simulate the formation fracture channel. The wall surface 1 of the flat plate device is made of concrete, a visualization module, and an electromagnetic induction material, and can generate stress changes under the action of an electromagnetic field;

[0030] The electromagnetic generating device 2 is arranged around the outside of the wall surface 1 of the flat plate device; the electromagnetic generating device 2 includes a plurality of electromagnetic coils. The electromagnetic generating device 2 is used to generate an electromagnetic force to control the wall surface 1 of the flat plate device, and regulate the closed stress of the wall surface 1 of the flat plate device through the generated electromagnetic force; the electromagnetic coils can independently generate electromagnetic fields of different intensities and directions, and precisely control the electromagnetic force of the wall surface 1 of the flat plate device by changing the parameters of the electromagnetic field, so as to realize the regulation of the closed stress;

[0031] The stress monitoring module 3 is arranged on the wall surface 1 of the flat plate device. The stress monitoring module 3 is used to monitor the stress condition of the wall surface 1 of the flat plate device in real time and feedback data;

[0032] The control system 4 is used to receive the data fed back by the stress monitoring module 3, and intelligently control the current size, direction and on-off time of each electromagnetic coil in the electromagnetic generating device 2 according to the preset stress parameters, so as to realize the accurate and dynamic control of the closing stress of the wall surface 1 of the flat plate device, so that it can simulate the stress environment under different formation conditions and meet the needs of multi-scale proppant migration experiments.

[0033] The present invention can accurately simulate the stress environment under various complex formation conditions in a large-scale multi-scale proppant migration flat plate device, providing a reliable experimental means for in-depth research on the proppant migration law, helping to improve the research and development efficiency and level of oil and gas field fracturing production technology, and promoting the development of the oil and gas industry.

[0034] To further optimize the solution, the electromagnetic coil is made of high temperature resistant and high conductivity materials to ensure stable operation under long-term and high-intensity electromagnetic fields, and can quickly respond to the instructions of the control system 4 to achieve precise adjustment of the electromagnetic field.

[0035] To further optimize the solution, the stress monitoring module 3 uses a high-precision strain gauge sensor and / or a fiber grating sensor. It can accurately measure tiny stress changes and has high sensitivity, high reliability and anti-interference ability, ensuring the accuracy and stability of feedback data, and providing a reliable basis for the precise control of the control system 4.

[0036] To further optimize the solution, the control system 4 adopts an advanced programmable logic controller PLC or digital signal processor DSP, which can independently, quickly and accurately control multiple electromagnetic coils, and also has data storage, analysis and visualization functions, so that the experimenters can monitor the stress data in real time and conduct subsequent analysis and research during the experiment.

[0037] To further optimize the solution, the wall material on one side of the flat device wall 1 is cement gravel prepared using real stratum characteristics or a tortuous wall precisely prepared from rock samples after fracturing to simulate real roughness and filtration; the other side is a visualized tortuous transparent wall obtained through 3D scanning and printing. Both are integrated with an electromagnetic force control system to apply different closing stresses to the wall through an electromagnetic field. Under the action of the electromagnetic field, the wall can respond and adjust in real time to simulate the effect of rock formations on proppants under different pressures. While ensuring the electromagnetic induction performance, it has sufficient strength and wear resistance to resist the scouring and wear of the wall by the proppant during migration, thereby extending the service life of the device and ensuring the stability and reliability of stress control during the experiment.

[0038] An operating method of a wall electromagnetic controlled closed stress system based on a multi-scale proppant transport flat plate device comprises the following steps:

[0039] S1. According to the formation stress conditions to be simulated, preset the target closure stress parameters for each area of the wall surface 1 of the flat plate device in the control system 4;

[0040] S2. Start the electromagnetic generating device 2, and the control system 4 sends control signals to each electromagnetic coil according to the preset parameters, so that the electromagnetic coil generates an electromagnetic field with corresponding intensity and direction;

[0041] S3. Conduct a proppant transport experiment, use the stress monitoring module 3 to monitor the stress change of the wall surface 1 of the flat plate device in real time, and transmit the monitoring data back to the control system 4;

[0042] S4. The control system 4 analyzes and processes the data fed back by the stress monitoring module 3, compares it with the preset stress parameters, and dynamically adjusts the electromagnetic field parameters of each electromagnetic coil in the electromagnetic generating device 2 according to the comparison results, so as to ensure that the closure stress of the wall surface 1 of the flat plate device always remains within the preset range.

[0043] Embodiment 1

[0044] Conduct a proppant transport experiment under the stress environment of a low-permeability formation. The experimental scheme is as follows:

[0045] 1. The experimenter sets the closure stress parameters for simulating a low-permeability formation in the control system 4; for this formation condition, the average closure stress of the wall surface 1 of the preset flat plate device is 50 MPa, and the stress is slightly lower at the channel entrance, which is 45 MPa, and gradually increases along the channel to 55 MPa at the exit to simulate the stress gradient caused by the change of formation fluid pressure;

[0046] 2. Check each electromagnetic coil of the electromagnetic generating device 2 to ensure its normal operation; the electromagnetic coil is made of copper alloy material, has good high-temperature resistance and high conductivity, and can withstand the action of a high-intensity electromagnetic field for a long time;

[0047] 3. The stress monitoring module 3 uses a high-precision fiber Bragg grating sensor, whose accuracy can reach ±0.1 MPa, and is calibrated before the experiment to ensure accurate measurement of the stress change of the wall surface 1 of the flat plate device;

[0048] 4. Start the electromagnetic generating device 2, and the control system 4 sends control signals to each electromagnetic coil according to the preset parameters; the electromagnetic coil generates an electromagnetic field with a specific distribution, which acts on the electromagnetic induction wall surface of the wall surface 1 of the flat plate device, so that the wall surface 1 of the flat plate device generates a corresponding electromagnetic force, thereby forming a closure stress distribution that conforms to the preset;

[0049] 5. Inject the simulated fracturing fluid mixed with multi-scale proppants (including three different particle sizes of proppants: 20 / 40 mesh, 40 / 70 mesh, and 70 / 140 mesh, with a ratio of 3:5:2) into the simulated formation fracture channel on the wall surface 1 of the flat plate device at a flow rate of 1 m / s;

[0050] 6. During the proppant migration process, the stress monitoring module 3 monitors the wall stress changes in real time and feeds the data back to the control system 4. For example, when it is monitored that the stress at a certain position in the channel fluctuates by 2 MPa due to proppant accumulation, the control system 4 quickly adjusts the current of the electromagnetic coil near this area, increasing the electromagnetic field intensity, thereby increasing the wall electromagnetic force and adjusting the closure stress back to the preset value to ensure the stability of the stress environment during the experiment;

[0051] 7. By observing and recording the migration trajectory, settlement distribution, etc. of the proppant in the simulated low-permeability formation stress environment, it is found that smaller-sized proppants are more likely to aggregate in low-stress areas, while larger-sized proppants tend to be distributed in high-stress areas, which is consistent with the theoretical expectation, verifying that the present invention can effectively simulate the stress conditions of low-permeability formations and providing reliable experimental data for further studying the migration law of proppants in such formations.

[0052] Example Two

[0053] An experiment on proppant migration in a simulated high-stress complex fracture network formation is carried out with the following experimental scheme:

[0054] 1. For the simulated high-stress complex fracture network formation, a complex stress parameter mode is set in the control system 4. For example, the average closure stress is set to 80 MPa on the main fracture channel wall of the flat plate device wall 1, and at the same time, a stress concentration area is set at the starting point of the branch fracture, with a stress peak of up to 100 MPa, and the stress direction has a certain angular change in different areas to simulate the complex stress distribution in the actual formation fracture network;

[0055] 2. The electromagnetic coils of the electromagnetic generating device 2 are made of a special silver-based composite material, which has a higher conductivity and better electromagnetic response performance and can meet the requirements of rapid changes in high-intensity electromagnetic fields;

[0056] 3. The stress monitoring module 3 uses a high-sensitivity strain gauge sensor array, which can monitor the stress changes at multiple positions simultaneously and has anti-interference ability, enabling accurate operation in a complex electromagnetic field environment;

[0057] 4. Turn on the electromagnetic generating device 2, and the control system 4 controls the operation of each electromagnetic coil according to the preset complex stress parameters to accurately generate the required electromagnetic field distribution, so that the flat plate device wall 1 forms a corresponding high-stress complex distribution pattern;

[0058] 5. Inject the simulated fracturing fluid containing proppants of various shapes (spherical, elliptical, and columnar) and particle sizes (16 / 30 mesh, 30 / 50 mesh, and 40 / 70 mesh, with a ratio of 4:3:3) into the main fracture channel of the wall surface 1 of the flat plate device at a flow rate of 1.5 m / s, and allow part of the fracturing fluid and proppants to enter the branched fractures through a special diversion device;

[0059] 6. During the experiment, the stress monitoring module 3 continuously monitors the change of wall stress and transmits the data to the control system 4 in real time; when it is found that the stress distribution changes abnormally due to the accumulation of proppants at the entrance of the branched fractures, the control system 4 immediately adjusts the electromagnetic field parameters of the electromagnetic coils in this area and coordinates the operation of the electromagnetic coils in the adjacent areas to maintain the stability and preset complex distribution state of the wall stress of the entire fracture network;

[0060] 7. After the experiment, conduct a detailed analysis of the migration of proppants in the simulated high-stress complex fracture network formation.

[0061] The results show that proppants of different shapes and particle sizes exhibit obvious sorting phenomena in a complex stress environment. Spherical proppants migrate relatively smoothly in the main fractures, while columnar proppants are more likely to be retained and bridged at the starting points of the branched fractures where stress is concentrated. This result further verifies that this electromagnetic control closing stress system can accurately simulate the stress conditions of high-stress complex fracture network formations, provides strong experimental support for the optimization design of proppants in complex fracture networks during oil and gas field fracturing exploitation, and helps to improve the efficiency and effectiveness of oil and gas exploitation.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A multi-scale proppant transport flat-plate device wall electromagnetic control closing stress system, characterized in that Comprising: The wall surface (1) of the flat plate device is used to simulate the formation fracture channel. One side wall surface of the flat plate device wall surface (1) is a tortuous wall surface that can simulate real roughness and filtration loss, prepared with real formation characteristics of cement gravel or fractured rock samples. The other side is a visualized tortuous transparent wall surface formed by 3D scanning and printing. Both are integrated with an electromagnetic force control system; The electromagnetic generating device (2) is arranged around the outside of the wall surface (1) of the flat plate device; the electromagnetic generating device (2) includes a plurality of electromagnetic coils, and the electromagnetic generating device (2) is used to generate electromagnetic force to control the wall surface (1) of the flat plate device, and regulate the closing stress of the wall surface (1) of the flat plate device through the generated electromagnetic force; The stress monitoring module (3) is arranged on the wall surface (1) of the flat plate device, and the stress monitoring module (3) is used to monitor the stress condition of the wall surface (1) of the flat plate device in real time and feedback data; The control system (4) is used to receive the data fed back by the stress monitoring module (3), and control the working state of each electromagnetic coil in the electromagnetic generating device (2) according to the preset stress parameters; The electromagnetic coil is made of copper alloy material or silver-based composite material; The stress monitoring module (3) adopts high-precision strain gauge sensors and / or fiber Bragg grating sensors; The operation method of this system includes the following steps: S1. According to the formation stress conditions to be simulated, preset the target closing stress parameters of each area of the wall surface (1) of the flat plate device in the control system (4); S2. Start the electromagnetic generating device (2), and the control system (4) sends control signals to each electromagnetic coil according to the preset parameters, so that the electromagnetic coils generate electromagnetic fields with corresponding intensities and directions; S3. Conduct a proppant transport experiment, inject a simulated fracturing fluid mixed with multi-scale and / or various-shaped proppants into the simulated formation fracture channel on the wall surface (1) of the flat plate device, use the stress monitoring module (3) to monitor the stress change of the wall surface (1) of the flat plate device in real time, and transmit the monitoring data back to the control system (4); S4. The control system (4) analyzes and processes the data fed back by the stress monitoring module (3), compares it with the preset stress parameters, and dynamically adjusts the electromagnetic field parameters of each electromagnetic coil in the electromagnetic generating device (2) according to the comparison result to ensure that the closing stress of the wall surface (1) of the flat plate device always remains within the preset range.

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