A method for evaluating performance of temporary plugging agent based on large-scale physical model experiment

Abstract

The application discloses a method for evaluating performance of temporary plugging agents based on large-scale physical model experiments, comprising: preparing experimental rock samples and multiple temporary plugging agent samples with different chemical compositions and different concentrations, wherein the experimental rock samples are large-scale physical model rock samples with size specifications up to one meter or above; an experimental device adopts a large-scale physical model experimental device, and experimental parameters are adjusted by adjusting the types, concentrations and injection amounts of temporary plugging agents; the experimental rock samples are placed in the large-scale physical model experimental device, different types of temporary plugging agent samples are sequentially injected into multiple series-connected experimental rock samples through the large-scale physical model experimental device, and a performance evaluation simulation experiment of temporary plugging agents is started; pressure and flow data, acoustic wave detection data, optical imaging data, nuclear magnetic resonance detection data and CT scanning data in the performance evaluation simulation experiment of temporary plugging agents are monitored in real time; a multidimensional analysis system of plugging effects of temporary plugging agents is constructed by combining five-dimensional data of pressure, acoustic waves, optics, nuclear magnetic resonance and CT, and performance of the temporary plugging agents is evaluated.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, specifically to a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. Background Technology

[0002] In the fields of oil and gas field development and geological engineering, the application of temporary plugging agents is one of the key technologies for improving oil recovery and optimizing drilling operations. Temporary plugging agents are mainly used to seal high-permeability layers or fractures, thereby guiding fluids into low-permeability layers to achieve balanced displacement and improve oil recovery. With the deepening of oil and gas field development, reservoir conditions are becoming increasingly complex, and the performance requirements for temporary plugging agents are also becoming more stringent. Therefore, developing an effective method for evaluating the performance of temporary plugging agents is of great significance for optimizing the selection and application of these agents.

[0003] Traditional methods for evaluating the performance of temporary plugging agents mainly rely on small-scale experiments and numerical simulations. While these methods can provide some reference, their limited experimental scale often makes it difficult to accurately reflect the temporary plugging effect under actual reservoir conditions. Furthermore, small-scale experiments cannot fully account for factors such as reservoir heterogeneity, fracture development, and the complexity of fluid flow, leading to significant discrepancies between evaluation results and actual application effects.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. By simulating actual reservoir conditions and combining various high-precision detection technologies, this method comprehensively and accurately assesses the plugging effect, pressure resistance, temperature resistance, and distribution of temporary plugging agents in layers with different permeability levels. This method aims to overcome the limitations of traditional small-scale experiments and numerical simulations in evaluating temporary plugging agent performance, such as small experimental scale, inability to accurately reflect complex reservoir conditions, and significant deviations between evaluation results and practical applications. By systematically adjusting the type and dosage of temporary plugging agents, the selection and application of temporary plugging agents are optimized, reducing costs in oil and gas field development and geological engineering, improving construction efficiency, and providing a reliable experimental platform and data support for the research and development of temporary plugging agents. This promotes further innovation and development of temporary plugging agent technology, ultimately achieving efficient development and utilization of oil and gas resources.

[0006] Specifically, the following technical solution was adopted:

[0007] A method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, comprising:

[0008] Prepare experimental rock samples and various temporary plugging agent samples with different chemical compositions and concentrations. The experimental rock samples are large physical model rock samples with a size of more than one meter.

[0009] The experimental setup uses a large-scale physical model experimental device. The experimental parameters are adjusted by changing the type, concentration, and injection volume of the temporary plugging agent. The experimental rock sample is placed in the large-scale physical model experimental device, and different types of temporary plugging agent samples are injected sequentially into multiple experimental rock samples connected in series through the large-scale physical model experimental device to start the simulation experiment for evaluating the performance of the temporary plugging agent.

[0010] Real-time monitoring of pressure and flow data, acoustic wave detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data during the simulation experiment for evaluating the performance of the temporary plugging agent;

[0011] By combining five-dimensional data—pressure, acoustic wave, optical, nuclear magnetic resonance, and CT—a multi-dimensional analysis system for the sealing effect of temporary plugging agents is constructed to evaluate the performance of these agents.

[0012] As an optional embodiment of the present invention, in a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, the large-scale physical model experimental apparatus includes:

[0013] A casing, wherein multiple experimental rock samples are connected in series, and each experimental rock sample includes at least one transparent artificial rock core;

[0014] The fracturing pump truck system is connected to the casing and is used to simulate the fluid displacement process;

[0015] The stress loading system includes multiple sets of stress loading modules set around each experimental rock sample to simulate the interlayer stress difference of the target reservoir;

[0016] The temperature control system includes multiple temperature regulating devices, each corresponding to one of the experimental rock samples. The temperature of the experimental rock samples is adjusted according to the temperature of the target reservoir to simulate the temperature conditions of the target reservoir.

[0017] The data acquisition system is used to monitor and record pressure and flow data, acoustic detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data in real time during the simulation experiment of the performance evaluation of the temporary plugging agent.

[0018] As an optional embodiment of the present invention, in a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, the data acquisition system includes:

[0019] Pressure sensors and flow meters are installed at the inlet and outlet of the casing, respectively, to monitor in real time the pressure and flow rate changes of the fluid before and after passing through the temporary plugging area in the experimental rock sample. The changes in orifice friction are calculated using the pressure difference and flow rate data.

[0020] An acoustic transmitter and receiver are installed on the casing to evaluate the distribution and sealing effect of the temporary plugging agent in the experimental rock sample by the attenuation or reflection of the acoustic signal.

[0021] High-speed cameras are used to monitor and observe the distribution and fluid flow of the temporary plugging agent in transparent artificial rock cores in real time.

[0022] Nuclear magnetic resonance spectrometer: The experimental rock sample that has completed the simulation experiment of evaluating the performance of the temporary plugging agent is placed in the nuclear magnetic resonance spectrometer to detect the distribution of fluid in the experimental rock sample and evaluate the plugging effect of the temporary plugging agent.

[0023] The experimental rock sample, which has undergone a simulation experiment to evaluate the performance of the temporary plugging agent, is placed in the CT scanner to obtain a three-dimensional distribution image of the temporary plugging agent in the experimental rock sample and to quantitatively analyze its plugging performance.

[0024] As an optional embodiment of the present invention, a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment is provided by the present invention. Based on the basic mechanical data provided by the pressure sensor and the flow meter, and combined with the acoustic detection data provided by the acoustic transmitter and receiver, the method monitors and calibrates in real time, and dynamically updates the parameters of the friction calculation formula through a Bayesian filtering algorithm.

[0025] The friction calculation formula is based on a modified Darcy-Weisbach formula model in fluid mechanics:

[0026] In the formula, λ is called the friction coefficient, which is dimensionless and related to the fluid viscosity, Reynolds number Re, and the relative roughness of the pipe wall; l is the length of the pipe, d is the diameter of the pipe (for non-circular cross-section pipes, d is the equivalent diameter), and v is the average flow velocity on the effective cross-section of the pipe.

[0027] As an optional embodiment of the present invention, in a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, the method of constructing a multi-dimensional analysis system for the plugging effect of the temporary plugging agent by combining five-dimensional data of pressure, acoustic wave, optical wave, nuclear magnetic resonance and CT, and evaluating the performance of the temporary plugging agent, includes:

[0028] Mechanical response analysis: The orifice friction is calculated in real time based on the real-time monitoring data of the pressure sensor and the flow meter, and the model is corrected in real time by combining the Bayesian algorithm to dynamically monitor the pressure difference before and after the blockage.

[0029] Spatial distribution analysis: Based on the acoustic detection data provided by the acoustic transmitter and receiver, acoustic tomography and multi-channel array scanning are performed to construct a two-dimensional velocity field of the temporary plugging agent distribution;

[0030] Dynamic process analysis: Based on real-time image data acquired by a high-speed camera, the distribution of the temporary plugging agent and the fluid flow state can be observed intuitively;

[0031] 3D Reconstruction Analysis: After drilling and scanning the experimental rock samples that completed the simulation experiment for evaluating the performance of the temporary plugging agent, the spatial distribution of the temporary plugging agent was reconstructed in three dimensions.

[0032] Microstructure analysis: Based on nuclear magnetic resonance to measure changes in pore fluid permeability, the changes in fluid permeability within pores are analyzed, and the rate of decrease in permeability caused by blockage is quantified.

[0033] As an optional embodiment of the present invention, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0034] By designing a multi-gradient coupling experiment of pressure and temperature, we simulated the extreme conditions of high temperature and high pressure in deep reservoirs.

[0035] Pressure was applied in stages P1, P2, ..., Pn, with a preset time interval T0 for each stage of constant pressure to monitor leakage. Temperature was set in multiple levels t1, t2, ..., tn to test the thermal stability of the temporary plugging agent.

[0036] The thermal shear resistance of the temporary plugging agent was tested by using thermo-pressure co-loading technology combined with nuclear magnetic resonance to detect the internal fluid diffusion coefficient of the temporary plugging agent.

[0037] Based on experimental data, the performance of the temporary plugging agent under different pressure and temperature conditions was evaluated.

[0038] As an optional embodiment of the present invention, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0039] L9 (3) 4 An orthogonal experimental design was used to design 9 groups of experiments covering the type of temporary plugging agent (3 classes), concentration (3 levels), particle size (3 grades), and injection rate (3 levels).

[0040] Construct a multi-indicator weighted scoring model Where E represents the blocking efficiency, P r Withstand pressure retention rate, T s Represents temperature resistance stability, D r Represents degradation rate, Each has its own preset weighting coefficient;

[0041] The temporary plugging agent formulations that are most suitable for the target reservoir conditions are selected by scoring each group of temporary plugging agent types using a multi-index weighted scoring model S.

[0042] As an optional embodiment of the present invention, in a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, the plugging efficiency E is defined as the ability of the temporary plugging agent to impede fluid flow after plugging, and is measured by the change in flow rate or pressure before and after plugging: Formula: or ;

[0043] Parameter description: Q after Q before This indicates the flow rate (m³ / s) before and after the blockage.

[0044] ΔP after ΔP before This represents the pressure difference (Pa) before and after the sealing process.

[0045] The pressure retention rate Pr is defined as the stability of the temporary plugging agent under continuous pressure, and is characterized by the retention rate of plugging capacity after pressurization for a period of time.

[0046] formula:

[0047] Parameter description: E0 represents the initial blocking efficiency, E t This indicates the sealing efficiency after pressurization for a certain period of time;

[0048] Temperature stability (Ts) is defined as the ability of a temporary plugging agent to retain its performance under high-temperature conditions.

[0049] formula: ;

[0050] Parameter description: E 常温 E represents the plugging efficiency at room temperature. T Indicates the plugging efficiency at the target temperature;

[0051] Degradation rate Dr is defined as the ability of the temporary plugging agent to degrade under reservoir conditions, and it affects the subsequent unplugging effect.

[0052] formula: ;

[0053] Parameter description: m0 represents the initial temporary plugging agent mass (g), m t This indicates the remaining mass (g) after a certain period of degradation.

[0054] As an optional embodiment of the present invention, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0055] Based on the data analysis results, a performance prediction model was trained using the random forest algorithm, and the optimal parameters were iteratively searched using the Bayesian optimization algorithm to recommend the formulation and injection parameters of the temporary plugging agent.

[0056] The optimization effect was verified through repeated experiments.

[0057] As an optional embodiment of the present invention, in a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, the simulation experiment for evaluating the performance of the temporary plugging agent includes a temporary plugging agent injection process:

[0058] Pulsed injection was used to target the low-permeability layer of the experimental rock sample to promote the penetration of the nano-plugging agent into the micropores;

[0059] For the high-permeability layer of the experimental rock sample, a slug injection method was used to form a composite sealing layer of "particle bridging + gel filling".

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] This invention discloses a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. These experiments simulate actual reservoir conditions, providing a more realistic reflection of the performance of temporary plugging agents in complex geological environments. By adjusting the type and dosage of the temporary plugging agent, this method systematically evaluates its plugging effect, pressure resistance, temperature resistance, and distribution in layers with different permeability levels, thereby providing a scientific basis for oil and gas field development.

[0062] Large-scale physical model experiments typically use core samples or artificial core samples similar to those of actual reservoirs. By controlling experimental conditions (such as pressure, temperature, and fluid properties), the reservoir environment at different development stages is simulated. During the experiment, the performance of the temporary plugging agent is comprehensively evaluated by monitoring the fluid flow characteristics, pressure changes, and distribution of the temporary plugging agent. Furthermore, the application of detection technologies is crucial in large-scale physical model experiments. Various detection technologies, such as high-precision pressure sensors, flow meters, acoustic detection, optical imaging, nuclear magnetic resonance (NMR), and CT scans, can monitor changes in orifice friction in real time and assess the plugging effect of the temporary plugging agent. For example, pressure sensors and flow meters can record the pressure and flow rate changes of fluid before and after passing through the plugging area, thereby calculating the change in orifice friction; acoustic detection and optical imaging technologies can visually observe the distribution of the temporary plugging agent and the fluid flow state; and NMR and CT scans can provide high-resolution three-dimensional images of fluid distribution and temporary plugging agent migration. The integrated application of these detection technologies not only improves the accuracy and reliability of experimental data but also provides intuitive data support for optimizing the formulation of temporary plugging agents and construction parameters.

[0063] This invention provides a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. Its advantages include overcoming the conversion errors of similarity criteria and directly simulating complex conditions such as temperature, pressure, permeability, and fracture development in actual reservoirs, thus avoiding errors introduced by similarity criterion conversions in small-scale experiments. Furthermore, large-scale physical model experiments are compatible with various types of temporary plugging agents, allowing for flexible adjustment of the type, concentration, and injection volume to meet the needs of different reservoir conditions. Simultaneously, large-scale physical model experiments can simulate two typical scenarios: porosity plugging and fracture plugging, comprehensively evaluating the sealing effect of temporary plugging agents in porosities and fractures, providing more precise guidance for on-site construction.

[0064] More importantly, this invention provides a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. These experiments can realistically reproduce the reservoir stress environment, simulating the actual geomechanical state of the reservoir by precisely controlling the temperature, pressure, and stress conditions of the experimental setup. This high-precision environmental simulation capability enables industrial-scale temporary plugging experiment simulation, providing highly reliable predictions of the performance of temporary plugging agents in actual reservoirs. Through large-scale physical model experiments, the performance of temporary plugging agents in actual reservoirs can be more realistically reflected, providing a scientific basis for cost reduction and efficiency improvement in oil and gas field development and geological engineering.

[0065] In summary, the performance evaluation method for temporary plugging agents based on large-scale physical model experiments of this invention not only improves the accuracy and reliability of evaluation results but also provides strong support for cost reduction and efficiency improvement in oil and gas field development and geological engineering. With continuous technological advancements, this method is expected to be applied in a wider range of fields, further promoting the development of temporary plugging agent technology. Attached Figure Description

[0066] Figure 1 A flowchart of a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments according to an embodiment of the present invention;

[0067] Figure 2 A schematic diagram illustrating the structural principle of the large-scale physical model experimental device according to an embodiment of the present invention. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0069] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0070] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0071] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0072] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0073] See Figure 1 As shown in this embodiment, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0074] Experimental preparation: Prepare experimental rock samples and various temporary plugging agent samples with different chemical compositions and concentrations. The experimental rock samples are large physical model rock samples with a size of more than one meter.

[0075] Experimental conditions: The experimental setup uses a large-scale physical model experimental device. The experimental parameters are adjusted by changing the type, concentration, and injection volume of the temporary plugging agent. The experimental rock sample is placed in the large-scale physical model experimental device.

[0076] Injection of temporary plugging agent: Different types of temporary plugging agent samples are sequentially injected into multiple experimental rock samples connected in series through a large-scale physical model experimental device to start the simulation experiment for evaluating the performance of the temporary plugging agent;

[0077] Real-time monitoring and data acquisition: Real-time monitoring of pressure and flow data, acoustic detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data during the simulation experiment for evaluating the performance of the temporary plugging agent;

[0078] Data analysis: Combining five-dimensional data from pressure, acoustic wave, optical wave, nuclear magnetic resonance, and CT, a multi-dimensional analysis system for the sealing effect of temporary plugging agents is constructed to evaluate the performance of temporary plugging agents.

[0079] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. These experiments simulate actual reservoir conditions, providing a more realistic reflection of the performance of temporary plugging agents in complex geological environments. By adjusting the type and dosage of the temporary plugging agent, this method systematically evaluates its plugging effect, pressure resistance, temperature resistance, and distribution in layers with different permeability levels, thereby providing a scientific basis for oil and gas field development.

[0080] Large-scale physical model experiments typically use core samples or artificial core samples similar to those of actual reservoirs. By controlling experimental conditions (such as pressure, temperature, and fluid properties), the reservoir environment at different development stages is simulated. During the experiment, the performance of the temporary plugging agent is comprehensively evaluated by monitoring the fluid flow characteristics, pressure changes, and distribution of the temporary plugging agent. Furthermore, the application of detection technologies is crucial in large-scale physical model experiments. Various detection technologies, such as high-precision pressure sensors, flow meters, acoustic detection, optical imaging, nuclear magnetic resonance (NMR), and CT scans, can monitor changes in orifice friction in real time and assess the plugging effect of the temporary plugging agent. For example, pressure sensors and flow meters can record the pressure and flow rate changes of fluid before and after passing through the plugging area, thereby calculating the change in orifice friction; acoustic detection and optical imaging technologies can visually observe the distribution of the temporary plugging agent and the fluid flow state; and NMR and CT scans can provide high-resolution three-dimensional images of fluid distribution and temporary plugging agent migration. The integrated application of these detection technologies not only improves the accuracy and reliability of experimental data but also provides intuitive data support for optimizing the formulation of temporary plugging agents and construction parameters.

[0081] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. Its advantages lie in overcoming the conversion errors of similarity criteria, directly simulating the complex conditions of actual reservoirs such as temperature, pressure, permeability, and fracture development, thus avoiding errors introduced by similarity criterion conversions in small-scale experiments. Furthermore, large-scale physical model experiments are adaptable to various types of temporary plugging agents, allowing for flexible adjustment of the type, concentration, and injection volume to meet the needs of different reservoir conditions. Simultaneously, large-scale physical model experiments can simulate two typical scenarios: porosity plugging and fracture plugging, comprehensively evaluating the sealing effect of temporary plugging agents in porosities and fractures, providing more precise guidance for on-site construction.

[0082] More importantly, this embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments. These experiments can realistically reproduce the reservoir stress environment, simulating the actual geomechanical state of the reservoir by precisely controlling the temperature, pressure, and stress conditions of the experimental setup. This high-precision environmental simulation capability enables industrial-grade temporary plugging experiment simulation, providing highly reliable predictions of the performance of temporary plugging agents in actual reservoirs. Through large-scale physical model experiments, the performance of temporary plugging agents in actual reservoirs can be more realistically reflected, providing a scientific basis for cost reduction and efficiency improvement in oil and gas field development and geological engineering.

[0083] In summary, the temporary plugging agent performance evaluation method based on large-scale physical model experiments presented in this embodiment not only improves the accuracy and reliability of the evaluation results but also provides strong support for cost reduction and efficiency improvement in oil and gas field development and geological engineering. With continuous technological advancements, this method is expected to be applied in a wider range of fields, further promoting the development of temporary plugging agent technology.

[0084] This embodiment of a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes: defining the research objectives and scale range, and determining the scale range to be covered, including the type, concentration, injection volume, and core type of the temporary plugging agent.

[0085] This includes defining research objectives and scale ranges, covering:

[0086] At the mineral level, the interaction between the temporary plugging agent and the mineral surface is analyzed to assess its impact on mineral wettability and adsorption.

[0087] Crack level is used to evaluate the sealing effect of temporary plugging agents in cracks, including changes in crack width, length, and permeability.

[0088] At the pore level, the migration and plugging behavior of temporary plugging agents in pores are studied, and their adaptability to pore structures is evaluated.

[0089] The study simulates the overall distribution and sealing effect of temporary plugging agents in rock strata across a wide range of rock layers, evaluates their impact on fluid flow, and analyzes the differential distribution patterns of temporary plugging agents in high-permeability layers (500mD) and low-permeability layers (10mD).

[0090] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, such as... Figure 2 As shown, the large-scale physical model experimental setup used includes:

[0091] A casing 600 is provided, wherein multiple experimental rock samples 100 are connected in series, and each experimental rock sample 100 includes at least one transparent artificial rock core.

[0092] The fracturing pump truck system 300 is connected to the casing 600 and is used to simulate the fluid displacement process.

[0093] The stress loading system includes multiple sets of stress loading modules set around each experimental rock sample 100 to simulate the interlayer stress difference of the target reservoir;

[0094] The temperature control system includes multiple temperature regulating devices, each corresponding to one of the experimental rock samples. The temperature of the experimental rock samples is adjusted according to the temperature of the target reservoir to simulate the temperature conditions of the target reservoir.

[0095] The data acquisition system is used to monitor and record pressure and flow data, acoustic detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data in real time during the simulation experiment of the performance evaluation of the temporary plugging agent.

[0096] Specifically, in the method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments in this embodiment, the data acquisition system includes:

[0097] Pressure sensors and flow meters are installed at the inlet and outlet of the casing, respectively, to monitor in real time the pressure and flow rate changes of the fluid before and after passing through the temporary plugging area in the experimental rock sample. The changes in orifice friction are calculated using the pressure difference and flow rate data.

[0098] An acoustic transmitter and receiver are installed on the casing to evaluate the distribution and sealing effect of the temporary plugging agent in the experimental rock sample by the attenuation or reflection of the acoustic signal.

[0099] High-speed cameras are used to monitor and observe the distribution and fluid flow of the temporary plugging agent in transparent artificial rock cores in real time.

[0100] Nuclear magnetic resonance spectrometer: The experimental rock sample that has completed the simulation experiment of evaluating the performance of the temporary plugging agent is placed in the nuclear magnetic resonance spectrometer to detect the distribution of fluid in the experimental rock sample and evaluate the plugging effect of the temporary plugging agent.

[0101] The experimental rock sample, which has undergone a simulation experiment to evaluate the performance of the temporary plugging agent, is placed in the CT scanner to obtain a three-dimensional distribution image of the temporary plugging agent in the experimental rock sample and to quantitatively analyze its plugging performance.

[0102] In this embodiment, a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment is used. Based on the basic mechanical data provided by the pressure sensor and the flow meter, and combined with the acoustic detection data provided by the acoustic transmitter and receiver, the parameters of the friction calculation formula are dynamically updated through a Bayesian filtering algorithm.

[0103] Friction calculation formulas are usually based on a modified Darcy-Weisbach formula model in fluid mechanics. The Darcy-Weisbach formula is a mathematical term used to calculate the friction loss along the flow path of viscous fluids in pipes.

[0104] In the formula, λ is called the friction factor, which is dimensionless and related to the fluid viscosity, Reynolds number Re, and the relative roughness of the pipe wall; l is the length of the pipe, d is the diameter of the pipe (for non-circular cross-section pipes, d is the equivalent diameter), and v is the average flow velocity on the effective cross-section of the pipe. The Darcy-Weisbach formula is applicable to fully developed laminar and turbulent (in engineering, often referred to as turbulent flow) flows in smooth and rough pipes of any cross-sectional shape, and has significant engineering implications.

[0105] In this embodiment, a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment is used. The method involves combining five-dimensional data (pressure, acoustic wave, optical, nuclear magnetic resonance, and CT) to construct a multi-dimensional analysis system for the plugging effect of the temporary plugging agent, and then evaluating the performance of the temporary plugging agent.

[0106] Mechanical response analysis: The orifice friction is calculated in real time based on the real-time monitoring data of the pressure sensor and the flow meter, and the model is corrected in real time by combining the Bayesian algorithm to dynamically monitor the pressure difference before and after the blockage.

[0107] Spatial distribution analysis: Based on the acoustic detection data provided by the acoustic transmitter and receiver, acoustic tomography and multi-channel array scanning are performed to construct a two-dimensional velocity field of the temporary plugging agent distribution;

[0108] Dynamic process analysis: Based on real-time image data acquired by a high-speed camera, the distribution of the temporary plugging agent and the fluid flow state can be observed intuitively;

[0109] 3D Reconstruction Analysis: After drilling and scanning the experimental rock samples that completed the simulation experiment for evaluating the performance of the temporary plugging agent, the spatial distribution of the temporary plugging agent was reconstructed in three dimensions.

[0110] Microstructure analysis: Based on nuclear magnetic resonance to measure changes in pore fluid permeability, the changes in fluid permeability within pores are analyzed, and the rate of decrease in permeability caused by blockage is quantified.

[0111] As an optional implementation of this embodiment, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0112] By designing a multi-gradient coupling experiment of pressure and temperature, we simulated the extreme conditions of high temperature and high pressure in deep reservoirs.

[0113] Pressure was applied in stages P1, P2, ..., Pn, with a preset time interval T0 for each stage of constant pressure to monitor leakage. Temperature was set in multiple levels t1, t2, ..., tn to test the thermal stability of the temporary plugging agent.

[0114] The thermal shear resistance of the temporary plugging agent was tested by using thermo-pressure co-loading technology combined with nuclear magnetic resonance to detect the internal fluid diffusion coefficient of the temporary plugging agent.

[0115] Based on experimental data, the performance of the temporary plugging agent under different pressure and temperature conditions was evaluated.

[0116] Therefore, this embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, which realizes the assessment of the pressure resistance and temperature resistance of temporary plugging agents: based on experimental data, the performance of temporary plugging agents under different pressure and temperature conditions is evaluated.

[0117] As an optional implementation of this embodiment, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0118] L9 (3) 4 An orthogonal experimental design was used to design 9 groups of experiments covering the type of temporary plugging agent (3 classes), concentration (3 levels), particle size (3 grades), and injection rate (3 levels).

[0119] Construct a multi-indicator weighted scoring model Where E represents the blocking efficiency, P r Withstand pressure retention rate, T s Represents temperature resistance stability, D r Represents the degradation rate. Each has its own preset weighting coefficient;

[0120] The temporary plugging agent formulations that are most suitable for the target reservoir conditions are selected by scoring each group of temporary plugging agent types using a multi-index weighted scoring model S.

[0121] Therefore, this embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, which enables the comparison of temporary plugging agent performance: by comparing the experimental data of different temporary plugging agent samples, the most suitable temporary plugging agent formulation for the target reservoir conditions is selected.

[0122] Specifically, the plugging efficiency E, pressure retention rate Pr, temperature stability Ts, and degradation rate Dr need to be calculated using experimental data or theoretical models.

[0123] 1. Blocking efficiency E

[0124] Definition: The ability of a temporary plugging agent to impede fluid flow after plugging, usually measured by changes in flow rate or pressure before and after plugging. Formula: or .

[0125] Parameter description:

[0126] Q after Q before : Flow rate before and after closure (m³ / s);

[0127] ΔP after ΔP before : Pressure difference (Pa) before and after sealing.

[0128] Experimental procedure: In core flow experiments or fracture models, measure the flow rate / pressure difference before and after the injection of the temporary plugging agent.

[0129] 2. Pressure retention rate Pr

[0130] Definition: The stability of a temporary plugging agent under continuous pressure is characterized by the retention rate of its plugging capacity after a period of pressurization.

[0131] formula: .

[0132] Parameter description:

[0133] E0: Initial blocking efficiency;

[0134] E t The sealing efficiency after pressurization for a certain period of time.

[0135] Experimental procedure: Apply the target reservoir pressure to the plugged system, continuously monitor the pressure difference change, and calculate E. t .

[0136] 3. Temperature stability (Ts)

[0137] Definition: The ability of a temporary plugging agent to maintain its performance under high-temperature conditions.

[0138] formula: .

[0139] Parameter description:

[0140] E 常温 : Sealing efficiency at room temperature;

[0141] E T : Blocking efficiency at the target temperature.

[0142] Experimental procedure: Heat the experimental system to the reservoir temperature, and measure the plugging efficiency after maintaining the temperature.

[0143] 4. Degradation rate Dr

[0144] Definition: The degradation ability of temporary plugging agents under reservoir conditions, which affects the subsequent unplugging effect.

[0145] formula: .

[0146] Parameter description:

[0147] m0: Initial temporary plugging agent mass (g);

[0148] m t : The remaining mass (g) after a certain period of degradation.

[0149] Experimental procedure: Place the temporary plugging agent in the simulated reservoir fluid, and filter, dry and weigh it periodically.

[0150] 5. Multi-indicator weighted scoring model (S)

[0151] formula: .

[0152] Weight setting: The weight coefficients (w1, w2, w3, w4) need to be determined according to the reservoir requirements. Weights can also be determined using the Analytic Hierarchy Process (AHP) or expert scoring methods.

[0153] This embodiment of the method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments further includes:

[0154] Based on the data analysis results, a performance prediction model was trained using the random forest algorithm, and the optimal parameters were iteratively searched using the Bayesian optimization algorithm to recommend the formulation and injection parameters of the temporary plugging agent.

[0155] The optimization effect was verified through repeated experiments.

[0156] In this embodiment, a method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment includes a temporary plugging agent injection process:

[0157] Pulsed injection was used to target the low-permeability layer of the experimental rock sample to promote the penetration of the nano-plugging agent into the micropores;

[0158] For the high-permeability layer of the experimental rock sample, a slug injection method was used to form a composite sealing layer of "particle bridging + gel filling".

[0159] In this embodiment, a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments is provided. The experimental rock samples include natural rock cores similar to actual reservoirs and artificial rock cores with specific permeability and porosity. Both the natural and artificial rock cores are large-scale physical model rock samples with a size of one meter or more.

[0160] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, including data analysis and optimization:

[0161] Orifice friction calculation: Based on the data from the pressure sensor and flow meter, calculate the change in orifice friction before and after the fluid passes through the area sealed by the temporary plugging agent.

[0162] Blocking effect analysis: Combining data from acoustic detection, optical imaging, nuclear magnetic resonance and CT scan, the blocking effect of the temporary plugging agent and its impact on fluid flow are analyzed.

[0163] Pressure and temperature resistance evaluation: Based on experimental data, evaluate the performance of the temporary plugging agent under different pressure and temperature conditions.

[0164] Performance comparison of temporary plugging agents: By comparing the experimental data of different temporary plugging agent samples, the most suitable temporary plugging agent formulation for the target reservoir conditions is selected.

[0165] Optimization and Validation: Based on the data analysis results, optimize the formulation of the temporary plugging agent (such as adjusting the concentration or chemical composition) and injection parameters (such as injection rate or injection volume), and verify the optimization effect through repeated experiments.

[0166] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, including result output and application:

[0167] Temporary plugging agent performance evaluation report: Summarize experimental data and optimization results to generate a temporary plugging agent performance evaluation report, which describes in detail the plugging effect, pressure resistance, temperature resistance and other performance indicators of the temporary plugging agent.

[0168] Optimization suggestions: Based on the experimental results, we provide optimization suggestions for the temporary plugging agent formulation and injection parameters to provide a scientific basis for on-site construction.

[0169] Field application: Applying experimental results and optimization suggestions to field construction improves the actual application effect of temporary plugging agents and helps reduce costs and increase efficiency in oil and gas field development and geological engineering.

[0170] A specific implementation of the method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments in this embodiment is as follows:

[0171] 1. Setup and preparation of experimental setup

[0172] The experimental setup consists of: a casing for fixing the core; a fracturing pump unit for simulating the fluid displacement process; an independent confining pressure loading module: 8 independent stress loading units, capable of simulating interlayer stress differences up to 15 MPa (e.g., 20 MPa for high-permeability layers and 35 MPa for low-permeability layers); a temperature-pressure coordination system: temperature range of room temperature to 180℃ (accuracy ±1℃), pressure range of 0-80 MPa (pulse loading frequency 0.1-10 Hz), used to simulate reservoir conditions; and a data acquisition system for real-time recording of experimental data.

[0173] Core selection and preparation: Select natural cores similar to the actual reservoir, or prepare artificial cores with specific permeability and porosity. The core size is typically 2m × 2m × 2m. Before the experiment, clean and dry the cores to ensure that their surfaces are free of impurities.

[0174] Preparation of temporary plugging agent samples: Prepare multiple temporary plugging agent samples, including those with different chemical compositions (such as polymers, gels, particles, etc.) and different concentrations (such as 1%, 3%, 5%, etc.). Each temporary plugging agent sample should be clearly labeled for easy comparison in subsequent experiments.

[0175] 2. Experimental Conditions

[0176] Temperature setting: Set the temperature control chamber or heating device of the experimental setup according to the actual temperature of the target reservoir. For example, if the reservoir temperature is 80℃, then set the experimental temperature to 80℃.

[0177] Pressure setting: Adjust the pressure inside the experimental apparatus according to the actual pressure of the target reservoir through the pressure control system. For example, if the reservoir pressure is 20 MPa, then set the experimental pressure to 20 MPa.

[0178] Fluid injection parameter settings: Set the injection rate and injection volume of the fracturing pump unit. For example, set the injection rate to 1 mL / min and the injection volume to 100 mL.

[0179] 3. Temporary plugging agent injection and monitoring of plugging effect

[0180] Temporary plugging agent injection: For low-permeability layers, pulsed injection (frequency 0.5Hz) is used to promote the penetration of nano-plugging agents into micropores; for high-permeability layers, slug injection is used to form a composite plugging layer of "particle bridging + gel filling". The temporary plugging agent sample is injected into the core in the casing via a fracturing pump truck. The injection process must be kept stable to avoid air bubble formation. Different temporary plugging agent samples are injected sequentially, and the type, concentration, and injection volume of each sample are recorded.

[0181] Pressure and flow monitoring: Pressure sensors and flow meters are installed at the inlet and outlet of the casing to monitor pressure and flow rate changes in real time before and after the fluid passes through the temporary plugging agent sealing area. The change in orifice friction is calculated using the pressure difference and flow rate data.

[0182] Acoustic detection: An acoustic transmitter and receiver are installed outside the casing. The distribution and sealing effect of the temporary plugging agent in the core are evaluated by the attenuation or reflection of the acoustic signal.

[0183] Optical imaging: If transparent or semi-transparent cores are used, the distribution of the plugging agent and the fluid flow status can be observed in real time using a high-speed camera or fiber optic sensor.

[0184] Nuclear magnetic resonance (NMR) detection: The core is placed in an NMR spectrometer to detect the distribution of fluid in the core and to evaluate the sealing effect of the temporary plugging agent.

[0185] CT scan: The core is placed in a CT scanner to obtain a three-dimensional distribution image of the temporary plugging agent in the core and to quantitatively analyze its plugging performance.

[0186] 4. Data Analysis and Optimization

[0187] Orifice friction calculation: Based on the basic mechanical data provided by the pressure sensor (accuracy ±0.1MPa) and flow meter (accuracy ±0.5%), combined with real-time monitoring and calibration of acoustic wave detection data (resolution 1cm), the friction calculation formula parameters are dynamically updated through Bayesian filtering algorithm.

[0188] Analysis of Plugging Effectiveness: Combining five-dimensional data—pressure, acoustic wave, optical, MRI, and CT—a multi-dimensional analysis system for the clogging effectiveness of temporary plugging agents is constructed.

[0189] ①Mechanical response: The pressure sensor (accuracy ±0.1MPa) and flow meter (accuracy ±0.5%) calculate the orifice friction in real time, and combine the Bayesian algorithm to correct the model in real time, and dynamically monitor the pressure difference before and after the blockage;

[0190] ② Spatial distribution: Acoustic tomography, 16-channel array scanning, constructing a two-dimensional velocity field of the temporary plugging agent distribution, with a resolution of 1 cm;

[0191] ③ Dynamic process: High-speed cameras and fiber optic sensors are used to visually observe the distribution of the temporary plugging agent and the fluid flow state;

[0192] ④ Three-dimensional reconstruction: Large-size CT reconstruction, 2m core was located and scanned after drilling (50μm resolution) to reconstruct the spatial distribution of the sealing agent in three dimensions;

[0193] ⑤ Microstructure: Nuclear magnetic resonance (NMR) is used to measure changes in pore fluid permeability, analyze changes in fluid permeability within pores, and quantify the rate of permeability reduction caused by blockage.

[0194] Pressure and temperature resistance evaluation: Based on experimental data, evaluate the performance of the temporary plugging agent under different pressure and temperature conditions.

[0195] A multi-gradient coupled experiment of pressure (0-80MPa) and temperature (room temperature-180℃) was designed to simulate the extreme high-temperature and high-pressure conditions of deep reservoirs. Pressure was applied in stages of 20MPa, 40MPa, 60MPa, and 80MPa, with leakage monitored for 24 hours at each stage (accuracy ±5mL / h). Temperature was tested at four levels: 60℃, 120℃, 150℃, and 180℃, to assess the thermal stability of the plugging agent (mass loss rate ≤5% was considered acceptable). A combined temperature and pressure loading technique (e.g., 150℃ + 60MPa) was employed, combined with nuclear magnetic resonance (NMR) to detect the internal fluid diffusion coefficient of the plugging agent (D < 10⁻¹⁰ m² / s), to evaluate its thermal shear resistance. This approach overcomes the limitations of traditional single temperature and pressure tests, improving the agreement between experimental results and actual reservoir conditions by 30%.

[0196] Performance comparison of temporary plugging agents: By comparing the experimental data of different temporary plugging agent samples, the most suitable temporary plugging agent formulation for the target reservoir conditions is selected.

[0197] Using an L9(34) orthogonal experimental design, only 9 sets of experiments are needed to cover 81 combinations of variables, including temporary plugging agent type (3 classes), concentration (3 levels), particle size (3 grades), and injection rate (3 levels), reducing the testing workload by 89% compared to traditional full-factor experiments. A multi-index weighted scoring model was constructed (S=0.4E+0.3Pr+0.2Ts+0.1Dr), where the weights of plugging efficiency (E), pressure retention rate (Pr), temperature stability (Ts), and degradation rate (Dr) are 40%, 30%, 20%, and 10%, respectively. For example, the nano-temporary plugging agent C (concentration 1.8%) achieved a comprehensive score of 89.5, significantly better than polymer gel (78.2), and the quantitative results provide an objective basis for formulation screening.

[0198] Optimization and Validation: Based on the data analysis results, optimize the formulation of the temporary plugging agent (such as adjusting the concentration or chemical composition) and injection parameters (such as injection rate or injection volume), and verify the optimization effect through repeated experiments.

[0199] A performance prediction model trained using the random forest algorithm (historical data n=500+, prediction accuracy 92%), combined with a Bayesian optimization algorithm to iteratively search for optimal parameters, can recommend the best formulation (e.g., 1.8% concentration of nano-plugging agent, particle size 35nm) within 10 rounds, improving efficiency by 60% compared to manual trial and error. A three-level verification process was established: ① initial screening and elimination of inefficient formulations using small core samples (Φ2.5cm); ② verification of plugging stability at industrial-grade discharge rates (2m³ / min) using large physical models (2m×2m×2m); ③ field pilot tests to ensure application error ≤5%. This closed-loop system reduces the plugging agent development cycle from 3 months to 1.5 months and increases the field application success rate to over 90%.

[0200] 5. Results Output and Application

[0201] Temporary plugging agent performance evaluation report: Summarize experimental data and optimization results to generate a temporary plugging agent performance evaluation report, which describes in detail the plugging effect, pressure resistance, temperature resistance and other performance indicators of the temporary plugging agent.

[0202] Optimization suggestions: Based on the experimental results, we provide optimization suggestions for the temporary plugging agent formulation and injection parameters to provide a scientific basis for on-site construction.

[0203] Field application: Applying experimental results and optimization suggestions to field construction improves the actual application effect of temporary plugging agents and helps reduce costs and increase efficiency in oil and gas field development and geological engineering.

[0204] Example 1

[0205] This embodiment of a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments includes:

[0206] 1. Setup and preparation of experimental setup

[0207] Experimental setup composition:

[0208] Multi-environment coupling experimental chamber: The core chamber is made of high-strength alloy steel (pressure resistant 100MPa, temperature resistant 200℃), with built-in natural / artificial rock cores (size 2m×2m×2m); integrated annular heating belt (temperature control accuracy ±0.5℃), six-axis hydraulic loading system (simulating non-uniform stress, maximum load 50MPa), and corrosive fluid circulation unit (supporting carbon dioxide / H2S mixed gas injection).

[0209] Multi-scale detection system, including:

[0210] Mineral grade: An atomic force microscope (AFM) probe is embedded in the core surface to scan the interfacial adsorption energy between the plugging agent and the mineral in real time;

[0211] Pore ​​level: Microfluidic chips (pore size 1-100μm) are linked with high-speed fluorescence microscopes to quantify the retention rate of temporary plugging agents in micropores;

[0212] Crack level: A transparent sapphire crack model (crack width adjustable from 0.1-5mm) combined with laser particle velocimetry (PIV) dynamically captures the formation process of the sealing zone;

[0213] Rock stratigraphy level: 4D-CT scanner (1μm resolution, ≤10 seconds scanning interval) to reconstruct the three-dimensional distribution of temporary plugging agent and crack propagation trend.

[0214] Intelligent decision-making unit: Edge computing terminal processes multi-source data in real time, runs deep reinforcement learning (DRL) model, and dynamically optimizes temporary plugging agent parameters (concentration, injection rate, etc.).

[0215] Degradability testing module: Microbial reactor (simulating anaerobic environment) and oxidant injection device to evaluate the degradation rate and permeability recovery rate of the temporary plugging agent.

[0216] Core selection and processing: Select natural rock cores (permeability 10-1000mD) or 3D printed artificial rock cores (porosity 5-30%), clean and dry them and place them in the experimental chamber; AFM scanning points and microfluidic chip interfaces are pre-set on the surface of the rock cores to ensure multi-scale detection compatibility.

[0217] Temporary plugging agent sample preparation: Prepare polymer gels, nanoparticles, biodegradable temporary plugging agents, etc., with concentration gradients (1%-10%); label chemical components and degradation characteristics (e.g., temporary plugging agents containing enzyme-catalyzed degradation groups).

[0218] 2. Experimental Conditions

[0219] Temperature: An annular heating belt is set up according to the actual temperature of the reservoir (e.g., 150°C for shale gas reservoirs) for constant temperature control;

[0220] Pressure: Axial / confining pressure (e.g., 30 MPa) is applied via a hydraulic system to simulate reservoir stress state;

[0221] Chemical environment: Injection of formation water containing H2S (1000ppm), circulation of corrosive fluids;

[0222] Injection parameters: Initial injection rate 1-5 m³ / min (industrial-grade displacement), dynamically adjusted by the DRL model.

[0223] 3. Temporary plugging agent injection and monitoring of plugging effect

[0224] Multi-scale synchronous monitoring includes:

[0225] Mineral grade: AFM real-time output of the adsorption force curve of the temporary plugging agent on the surface of calcite / clay minerals;

[0226] Pore ​​level: Microfluidic chip records the transport path of temporary plugging agent in 50μm pores (fluorescent label);

[0227] Crack level: The PIV system calculates the sealing zone formation rate (e.g., 0.2 mm / s);

[0228] Rock stratigraphy: 4D-CT generates a three-dimensional density distribution map every 10 seconds to identify areas rich in temporary plugging agents.

[0229] Dynamic optimization includes: the DRL model identifies uneven occlusion areas based on CT data and automatically increases the injection rate (e.g., from 2 m³ / min to 3.5 m³ / min).

[0230] If the microfluidic chip shows a pore retention rate of less than 50%, it is recommended to add a nano-silica modifier.

[0231] 4. Data Analysis and Optimization

[0232] Plugging effect: Calculate the change in orifice friction (ΔP = inlet pressure - outlet pressure), and generate a pluralistic heat map of plunging efficiency by combining CT data.

[0233] Pressure resistance test: The pressure is increased to 50MPa in a stepwise manner, and the stability of the sealing strip is monitored (no crack propagation is observed in CT images).

[0234] Environmental assessment, including:

[0235] Degradation experiment: After 28 days of anaerobic culture, the degradation products (such as acetic acid and carbon dioxide) were detected by LC-MS. A toxicity index ≤0.5 was considered acceptable.

[0236] Permeability recovery experiment: The permeability recovery rate of the core after degradation is ≥90%.

[0237] Intelligent decision-making output: Multi-objective optimization of Pareto front plot (plugging efficiency vs. environmental friendliness vs. cost), recommending the optimal temporary plugging agent formulation (such as biodegradable temporary plugging agent C, concentration 4%).

[0238] 5. Results Output and Application

[0239] Report generation includes key indicators such as plugging efficiency (e.g., 92%), pressure resistance limit (e.g., 45MPa), and degradation rate (e.g., 95% degradation in 28 days).

[0240] On-site implementation: The optimized parameters are imported into the fracturing pump truck unit, and the DRL model is synchronized to the downhole control system in real time to achieve dynamic adjustment.

[0241] Example 2

[0242] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, enabling the evaluation of the performance of temporary plugging agents in high-temperature and high-pressure reservoirs.

[0243] Experimental parameters

[0244] Core dimensions: 2m×2m×2m.

[0245] Core permeability: high permeability layer (500 mD), low permeability layer (50 mD).

[0246] Experimental temperature: 120°C.

[0247] Experimental pressure: 30 MPa.

[0248] Temporary plugging agent type:

[0249] Temporary plugging agent A: Polymer gel, concentration 3%.

[0250] Temporary plugging agent B: Particulate temporary plugging agent, particle size range 50-100 μm, concentration 5%.

[0251] Injection parameters:

[0252] Injection rate: 2 m³ / min (industrial-grade displacement).

[0253] Injection volume: 2000 L (industrial scale).

[0254] Detection technology:

[0255] Pressure sensor: Monitors inlet and outlet pressure.

[0256] Flow meter: Monitors fluid flow rate.

[0257] Acoustic wave detection: to assess the distribution of temporary plugging agent.

[0258] CT scan: to obtain three-dimensional distribution images of the temporary plugging agent.

[0259] Experimental steps

[0260] Experimental preparation: Select natural rock cores, clean and dry them. Configure the experimental apparatus, setting the temperature and pressure. Prepare samples of temporary plugging agent A and temporary plugging agent B.

[0261] Temporary plugging agent injection: Inject temporary plugging agent A and record pressure, flow rate, and acoustic signals. Inject temporary plugging agent B and record pressure, flow rate, and acoustic signals.

[0262] Data monitoring: Real-time monitoring of pressure and flow rate changes, and calculation of orifice friction.

[0263] CT scans were used to obtain three-dimensional distribution images of the temporary plugging agent in the core.

[0264] Data analysis: Compare the plugging effects of temporary plugging agent A and temporary plugging agent B. Evaluate the pressure resistance and temperature resistance of the temporary plugging agents under high temperature and high pressure conditions.

[0265] Output results: Generate a performance evaluation report of the temporary plugging agent, and recommend the optimal type of temporary plugging agent and injection parameters.

[0266] Experimental results

[0267] Temporary plugging agent A exhibits good plugging effect under high temperature and high pressure conditions, but has poor pressure resistance.

[0268] Temporary plugging agent B has a significant sealing effect in high-permeability layers, and its pressure resistance and temperature resistance are superior to those of temporary plugging agent A.

[0269] Temporary plugging agent B is recommended, with an injection concentration of 5% and an injection rate of 2 m³ / min.

[0270] Example 3

[0271] This embodiment presents a method for evaluating the performance of temporary plugging agents based on large-scale physical model experiments, enabling the evaluation of the performance of temporary plugging agents in low-permeability reservoirs.

[0272] Experimental parameters

[0273] Core dimensions: 2m×2m×2m.

[0274] Core permeability: 10 mD.

[0275] Experimental temperature: 60°C.

[0276] Experimental pressure: 15 MPa.

[0277] Temporary plugging agent type:

[0278] Temporary plugging agent C: Nanoparticle type temporary plugging agent, particle size range 10-50 nm, concentration 1%.

[0279] Temporary plugging agent D: polymer gel, concentration 2%.

[0280] Injection parameters:

[0281] Injection rate: 0.5 m³ / min (industrial-grade displacement).

[0282] Injection volume: 1000 L (industrial scale).

[0283] Detection technology:

[0284] Pressure sensor: Monitors inlet and outlet pressure.

[0285] Flow meter: Monitors fluid flow rate.

[0286] Nuclear magnetic resonance (NMR): Detects fluid distribution.

[0287] Optical imaging: Observing the distribution of the temporary plugging agent.

[0288] Experimental steps

[0289] Experimental preparation: Select low-permeability artificial cores, clean and dry them. Configure the experimental apparatus, setting the temperature and pressure. Prepare samples of temporary plugging agent C and temporary plugging agent D.

[0290] Temporary plugging agent injection: Inject temporary plugging agent C and record pressure, flow rate, and NMR signals. Inject temporary plugging agent D and record pressure, flow rate, and NMR signals.

[0291] Data monitoring: Real-time monitoring of pressure and flow rate changes, and calculation of orifice friction. Optical imaging is used to observe the distribution of the temporary plugging agent in the core.

[0292] Data analysis: Compare the plugging effects of temporary plugging agents C and D. Evaluate the adaptability of the temporary plugging agents under low permeability conditions.

[0293] Output results: Generate a performance evaluation report of the temporary plugging agent, and recommend the optimal type of temporary plugging agent and injection parameters.

[0294] Experimental results

[0295] Temporary plugging agent C exhibits excellent plugging effect under low permeability conditions and can effectively enter micropores.

[0296] Temporary plugging agent D has a poor plugging effect in low-permeability layers and is difficult to distribute evenly.

[0297] Temporary plugging agent C is recommended, with an injection concentration of 1% and an injection rate of 0.5 m³ / min. The above embodiments are merely illustrative of the invention and not intended to limit the technical solutions described herein. Although this specification has described the invention in detail with reference to the above embodiments, the invention is not limited to the specific implementation methods described above. Therefore, any modifications or equivalent substitutions to the invention, and all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of this invention.

Claims

1. A method for evaluating the performance of a temporary plugging agent based on a large-scale physical model experiment, characterized in that, include: Prepare experimental rock samples and various temporary plugging agent samples with different chemical compositions and concentrations. The experimental rock samples are large physical model rock samples with a size of more than one meter. The experimental setup uses a large-scale physical model experimental device. The experimental parameters are adjusted by changing the type, concentration, and injection volume of the temporary plugging agent. The experimental rock sample is placed in the large-scale physical model experimental device, and different types of temporary plugging agent samples are injected sequentially into multiple experimental rock samples connected in series through the large-scale physical model experimental device to start the simulation experiment for evaluating the performance of the temporary plugging agent. Real-time monitoring of pressure and flow data, acoustic wave detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data during the simulation experiment for evaluating the performance of the temporary plugging agent; By combining five-dimensional data from pressure, acoustic wave, optics, nuclear magnetic resonance, and CT, a multi-dimensional analysis system for the sealing effect of temporary plugging agents is constructed to evaluate the performance of temporary plugging agents. The large-scale physical model experimental device includes: A casing, wherein multiple experimental rock samples are connected in series, and each experimental rock sample includes at least one transparent artificial rock core; The fracturing pump truck system is connected to the casing and is used to simulate the fluid displacement process; The stress loading system includes multiple sets of stress loading modules set around each experimental rock sample to simulate the interlayer stress difference of the target reservoir; The temperature control system includes multiple temperature regulating devices, each corresponding to one of the experimental rock samples. The temperature of the experimental rock samples is adjusted according to the temperature of the target reservoir to simulate the temperature conditions of the target reservoir. The data acquisition system is used to monitor and record pressure and flow data, acoustic detection data, optical imaging data, nuclear magnetic resonance detection data, and CT scan data in real time during the simulation experiment of the performance evaluation of the temporary plugging agent. The performance evaluation methods for temporary plugging agents include: L9(34) 4 Orthogonal experimental design, design 9 groups of experiments covering temporary plugging agent type 3, concentration 3, particle size 3, injection speed 3; Constructing a multi-index weighted scoring model wherein E represents occlusion efficiency, P r pressure retention rate, T s represents temperature stability, D r represents degradation rate, is a respective preset weight coefficient; The temporary plugging agent formulations that are most suitable for the target reservoir conditions are selected by scoring each group of temporary plugging agent types using a multi-index weighted scoring model S.

2. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 1, characterized in that, The data acquisition system includes: Pressure sensors and flow meters are installed at the inlet and outlet of the casing, respectively, to monitor in real time the pressure and flow rate changes of the fluid before and after passing through the temporary plugging area in the experimental rock sample. The change in orifice friction is calculated using the pressure difference and flow rate data. An acoustic transmitter and receiver are installed on the casing to evaluate the distribution and sealing effect of the temporary plugging agent in the experimental rock sample by the attenuation or reflection of the acoustic signal. High-speed cameras are used to monitor and observe the distribution and fluid flow of the temporary plugging agent in transparent artificial rock cores in real time. Nuclear magnetic resonance spectrometer: The experimental rock sample that has completed the simulation experiment of evaluating the performance of the temporary plugging agent is placed in the nuclear magnetic resonance spectrometer to detect the distribution of fluid in the experimental rock sample and evaluate the plugging effect of the temporary plugging agent. The experimental rock sample, which has undergone a simulation experiment to evaluate the performance of the temporary plugging agent, is placed in the CT scanner to obtain a three-dimensional distribution image of the temporary plugging agent in the experimental rock sample and to quantitatively analyze its plugging performance.

3. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 2, characterized in that, Based on the basic mechanical data provided by the pressure sensor and the flow meter, and combined with the acoustic detection data provided by the acoustic transmitter and receiver, the friction calculation formula parameters are dynamically updated through a Bayesian filtering algorithm. The friction calculation formula is modified based on the Darcy-Weisbach formula model in fluid mechanics: where λ, called the frictional resistance coefficient, is a dimensionless quantity related to the viscosity of the fluid, the Reynolds number Re, and the relative roughness of the pipe wall; / is the length of the pipe, d is the diameter of the pipe, for non-circular cross-section pipes d is the equivalent diameter, and v is the average flow velocity over the effective cross-section of the pipe.

4. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 2, characterized in that, The five-dimensional data of pressure-sound wave-optical-nuclear magnetic-CT are combined to build a multi-dimensional analysis system of temporary plugging agent plugging effect for performance evaluation of temporary plugging agent, including: Mechanical response analysis: Real-time calculation of hole friction based on real-time monitoring data of the pressure sensor and the flowmeter, real-time correction of the model by combining the Bayesian algorithm, and dynamic monitoring of the pressure difference before and after plugging; Spatial distribution analysis: Sound wave tomography based on sound wave detection data provided by the sound wave transmitter and receiver, multi-channel array scanning, and construction of a two-dimensional velocity field of temporary plugging agent distribution; Dynamic process analysis: Real-time image data collected by a high-speed camera to visually observe the distribution of temporary plugging agent and the flow state of fluid; Three-dimensional reconstruction analysis: Positioning and drilling of the experimental rock sample after the simulation experiment of temporary plugging agent performance evaluation, and three-dimensional reconstruction of the spatial distribution of temporary plugging agent; Microstructure analysis: Analysis of the change of fluid permeability in pores based on nuclear magnetic resonance measurement of pore fluid permeability, and quantification of the permeability reduction rate caused by plugging.

5. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 1, characterized in that, Including: Through the design of pressure and temperature multi-gradient coupling experiment, the extreme conditions of high temperature and high pressure in deep reservoir are simulated; Pressure is loaded in stages P1, P2, …, Pn, and the leakage amount is monitored at each stage with a constant pressure for a preset time interval T0, and the temperature is divided into t1, t2, …, tn, and the thermal stability of the temporary plugging agent is tested; Using temperature and pressure loading technology, the internal fluid diffusion coefficient of the temporary plugging agent is detected by nuclear magnetic resonance, and the heat shear resistance of the temporary plugging agent is tested; According to the experimental data, the performance of the temporary plugging agent under different pressure and temperature conditions is evaluated.

6. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 1, characterized in that, The plugging efficiency E is defined as the ability of the temporary plugging agent to hinder fluid flow after plugging, which is measured by the change of flow or pressure before and after plugging: Formula: or ​ Parameter description: Q after , Q before represents the flow before and after the plugging m³ / s; ΔP after , ΔP before represents the pressure difference Pa before and after the occlusion; The pressure retention rate Pr is defined as the stability of the temporary plugging agent under continuous pressure, which is characterized by the retention rate of plugging ability after a period of pressure: Equation: ; Parameter description: E0 represents initial plugging efficiency, E t represents plugging efficiency after pressurization for a certain time; The temperature stability Ts is defined as the performance retention ability of the temporary plugging agent in a high temperature environment: Formula: ; Parameter description: E 常温 represents the plugging efficiency at normal temperature, E T represents the plugging efficiency at target temperature; The degradation rate Dr is defined as the degradation ability of the temporary plugging agent in the reservoir conditions, which affects the subsequent plugging effect: Equation: ; Parameter description: m0 represents the initial temporary plugging agent mass g, m t represents the remaining mass g after degradation for a certain time.

7. The method for evaluating the performance of the temporary plugging agent based on the large-scale physical model experiment according to claim 1, characterized in that, Including: According to the data analysis results, a performance prediction model is trained based on the random forest algorithm, and the optimal parameters are iteratively searched by combining the Bayesian optimization algorithm to recommend the optimized formula and injection parameters of the temporary plugging agent; The optimization effect is verified by repeated experiments.

8. The method for evaluating the performance of the temporary plugging agent based on large-scale physical modeling experiments according to claim 1, characterized in that, The temporary plugging agent performance evaluation simulation experiment includes the temporary plugging agent injection process: Pulse injection is used for low-permeability layers of experimental rock samples to promote the deep penetration of nano temporary plugging agents into micro-pores; Segmented injection is used for high-permeability layers of experimental rock samples to form a "particle bridging + gel filling" composite plugging layer.

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