Hydrate sand production experiment system and testing method coupled with fracture morphology, formation particles and temperature and pressure conditions

Abstract

The present application relates to the technical field of hydrate sand production experiment, and discloses a hydrate sand production experiment system and a testing method coupling crack morphology, formation particles and temperature and pressure conditions, the system comprising: a reservoir simulation module; an environment regulation module; a process monitoring module configured to obtain crack response information, particle response information and sand production response information of a hydrate simulation reservoir in a hydrate decomposition process; a coupling analysis module configured to analyze the coupling relationship between crack structure, formation particles and experimental environment conditions according to the crack response information, the particle response information and the sand production response information, and determine the corresponding sand production evolution state according to the coupling relationship; and a state regulation module configured to adjust the experimental environment conditions according to the sand production evolution state to realize dynamic simulation of the hydrate reservoir sand production process. The present application realizes high-fidelity simulation of the multi-factor synergistic effect of the hydrate reservoir sand production process.

Description

Technical Field

[0001] This invention relates to the field of hydrate sand production experimental technology, and more specifically, to a hydrate sand production experimental system and testing method that couples fracture morphology, formation particles and temperature and pressure conditions. Background Technology

[0002] Natural gas hydrates are abundant clean energy resources, widely distributed in deep-sea sedimentary layers and permafrost regions. Hydrate reservoirs typically exist in low-temperature, high-pressure environments. During extraction, the reservoir's temperature and pressure conditions need to be altered through depressurization, heating, or fluid injection to induce hydrate decomposition and release of natural gas. However, hydrates reside within sediment pores, affecting not only reservoir permeability but also significantly influencing the cementation state between formation particles and the stability of the formation framework. After hydrate decomposition, the original internal support structure of the reservoir changes, easily inducing particle migration, fracture propagation, and sand production under fluid-driven conditions, thus impacting the stability and safety of the extraction process.

[0003] Currently, research on sand production behavior in hydrate reservoirs mainly relies on experimental simulation systems. These systems construct artificial reservoir models and control temperature, pressure, and seepage conditions to analyze particle migration patterns during hydrate decomposition. However, actual hydrate reservoirs typically possess complex heterogeneous structures, with significant coupling effects between fracture morphology, formation particle composition, and temperature and pressure evolution: fracture width, extension direction, and spatial distribution alter fluid migration paths and local pressure release processes; particle size, gradation, and arrangement affect particle initiation conditions and migration characteristics; and temperature and pressure variations determine the hydrate decomposition rate and the evolution of reservoir mechanical states.

[0004] Therefore, it is necessary to design an experimental system and testing method for hydrate sand production that couples fracture morphology, formation particles and temperature and pressure conditions to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes an experimental system and testing method for hydrate sand production that couples fracture morphology, formation particles and temperature and pressure conditions, aiming to solve the problem that existing experimental systems are unable to accurately reproduce the sand production behavior under the multi-field coupling of fractures, particles and temperature and pressure in hydrate reservoirs.

[0006] In one aspect, the present invention proposes a hydrate sand-producing experimental system that couples fracture morphology, formation particles, and temperature and pressure conditions, comprising: The reservoir simulation module is configured to construct a hydrate simulated reservoir and configure corresponding fracture structures and formation particle structures in the hydrate simulated reservoir. The environmental control module is configured to apply experimental environmental conditions to the hydrate simulated reservoir, causing the hydrates in the hydrate simulated reservoir to decompose and inducing fluid transport and particle migration processes inside the reservoir. The process monitoring module is configured to acquire fracture response information, particle response information, and sand production response information of the hydrate simulated reservoir during the hydrate decomposition process; The coupling analysis module is configured to analyze the coupling relationship between fracture structure, formation particles and experimental environmental conditions based on the fracture response information, particle response information and sand production response information, and determine the corresponding sand production evolution state based on the coupling relationship. The state control module is configured to adjust the experimental environment conditions according to the sand production evolution state in order to achieve dynamic simulation of the sand production process of hydrate reservoirs.

[0007] Furthermore, when constructing a hydrate-simulated reservoir and configuring corresponding fracture structures and formation particle structures within the hydrate-simulated reservoir, the following steps are included: Obtain the geological structural features corresponding to the target hydrate reservoir, and establish a simulated reservoir space model based on the geological structural features; Based on the heterogeneous structural features in the simulated reservoir space model, a fracture distribution structure matching the target reservoir is constructed inside the simulated hydrate reservoir. Based on the sedimentary characteristics corresponding to the target hydrate reservoir, the simulated particles are layered and configured so that different regions form corresponding particle composition structures. The fracture distribution structure is associated with the particle composition structure to form a hydrate simulated reservoir with spatial differences.

[0008] Furthermore, when applying experimental environmental conditions to the simulated hydrate reservoir, the following are included: Obtain the occurrence environment characteristics corresponding to the target hydrate reservoir, and determine the initial environmental state corresponding to the simulated hydrate reservoir based on the occurrence environment characteristics; According to the preset experimental conditions, temperature and pressure are adjusted on the hydrate simulated reservoir to change the thermodynamic state of the hydrate simulated reservoir. Based on the change process of the thermodynamic state, the hydrate decomposition process in the hydrate simulation reservoir is controlled, and a corresponding fluid transport state is formed inside the hydrate simulation reservoir. Based on the hydrate decomposition process and fluid transport state, the temperature regulation process and pressure regulation process are coordinated and controlled to form experimental environmental conditions that match the target hydrate reservoir exploitation process.

[0009] Furthermore, when controlling the hydrate decomposition process in the simulated hydrate reservoir based on the change in the thermodynamic state, and when establishing a corresponding fluid transport state within the simulated hydrate reservoir, the process includes: Based on the thermodynamic state change information corresponding to the simulated hydrate reservoir, the hydrate decomposition region and its corresponding decomposition evolution process are determined. Based on the decomposition and evolution process, information on the changes in fluid products generated by hydrate decomposition is obtained, and the fluid pressure change state inside the simulated hydrate reservoir is determined. Based on the fluid pressure change state, fracture structure, and particle structure, the migration path of the fluid inside the simulated hydrate reservoir is analyzed. The experimental control process corresponding to the hydrate decomposition process is adjusted according to the migration path so that the fluid migration state inside the simulated hydrate reservoir corresponds to the target reservoir extraction process.

[0010] Furthermore, when coordinating the temperature regulation process and the pressure regulation process based on the hydrate decomposition process and fluid transport state, the following are included: The hydrate decomposition state information and fluid migration state information corresponding to the simulated hydrate reservoir are collected, and the current reservoir evolution stage is determined based on the hydrate decomposition state information and fluid migration state information; wherein, the reservoir evolution stage includes the hydrate decomposition initiation stage, the fluid migration stage, and the sand production evolution stage; The corresponding temperature and pressure regulation mode is determined according to the reservoir evolution stage, and the initial temperature state and initial pressure state are adjusted according to the temperature and pressure regulation mode. When the simulated hydrate reservoir is in the hydrate decomposition initiation stage, it is determined to be in the first temperature and pressure regulation mode, and the internal pressure of the simulated hydrate reservoir is reduced to control the rate of temperature change. When the simulated hydrate reservoir is in the fluid migration stage, it is determined to be in the second temperature and pressure regulation mode, and the pressure change amplitude and temperature compensation amount inside the simulated hydrate reservoir are adjusted to match the fluid migration process. When the simulated hydrate reservoir is in the sand production evolution stage, it is determined to be in the third temperature and pressure regulation mode, and the internal pressure change process and temperature control process of the simulated hydrate reservoir are adjusted to adapt to the particle migration process.

[0011] Furthermore, when analyzing the coupling relationship between fracture structure, formation particles, and experimental environmental conditions based on the fracture response information, particle response information, and sand production response information, the analysis includes: The crack response information, particle response information, sand discharge response information, and corresponding experimental environmental conditions are synchronously mapped to establish a time-series response sequence of each response information as it changes during the experimental process. Based on the time-series response sequence, the sequential response relationship between fracture propagation, particle migration and sand production evolution is extracted to determine the evolution response path of the simulated hydrate reservoir from structural change to particle instability and then to sand production. Based on the evolution response path, the transmission relationship between fracture structure changes, formation particle migration and sand production behavior under different experimental conditions is identified, and the key response nodes affecting sand production evolution are determined. Based on the key response nodes, a coupled evolution relationship is constructed between fracture morphology, particle migration, and temperature and pressure response, and the sand production evolution state corresponding to the hydrate simulated reservoir is determined based on the coupled evolution relationship.

[0012] Furthermore, based on the aforementioned evolutionary response path, when identifying the transmission relationship between fracture structure changes, formation particle migration, and sand production behavior under different experimental conditions, and determining the key response nodes affecting sand production evolution, the following are included: Based on the evolution response path, the crack propagation rate change characteristics, particle migration rate change characteristics, and sand discharge rate change characteristics are extracted respectively to determine the change stage corresponding to each response process; Based on the change stages corresponding to each response process, the sequential relationship between fracture structure changes, formation particle migration and sand production behavior is identified, and the response transmission process caused by temperature and pressure changes is determined. Based on the response propagation process, the state transition characteristics between different response stages are obtained, and the response transition nodes corresponding to crack propagation acceleration, enhanced particle migration, and sudden change in sand discharge rate are determined. Based on the response transition nodes, the key response nodes that affect the sand production evolution process due to changes in experimental environmental conditions are identified.

[0013] Furthermore, when determining the corresponding sand production evolution state based on the aforementioned coupling relationship, the process includes: Based on the aforementioned coupling relationship, the response triggering relationship between changes in experimental environmental conditions and fracture structure response and formation particle migration is determined; Based on the aforementioned response triggering relationship, the continuous evolution process of crack propagation, particle instability, and sand production caused by temperature and pressure changes is identified; Based on the continuous evolution process, determine the state transition relationships corresponding to crack structure changes, particle migration, and sand discharge behavior during the current experiment. Based on the state transition relationship, the sand production evolution state corresponding to the hydrate simulated reservoir is determined.

[0014] Furthermore, adjusting the experimental environmental conditions according to the sand production evolution state includes: Based on the sand production evolution status, determine the current sand production evolution stage of the simulated hydrate reservoir, and obtain the environmental response requirements corresponding to the sand production evolution stage; Based on the environmental response requirements, determine the control direction corresponding to the experimental environmental conditions, and match and adjust the temperature control process and the pressure control process. When the hydrate simulated reservoir is in the particle migration enhancement stage, the pressure change amplitude is reduced according to the particle migration state, and the temperature control process is adjusted. When the simulated hydrate reservoir is in the rapid evolution stage of sand production, the pressure change path and temperature change process are adjusted according to the sand production evolution state. The experimental environmental conditions are updated based on the adjusted temperature and pressure regulation processes, and the response information corresponding to the hydrate simulated reservoir is continuously acquired.

[0015] Compared with existing technologies, the advantages of this invention are as follows: By constructing an experimental system and testing method for hydrate sand production that couples fracture morphology, formation particles, and temperature and pressure conditions, this invention achieves high-fidelity simulation of the synergistic effects of multiple factors on the sand production process in hydrate reservoirs. Traditional experimental methods focus only on a single variable or simplify the reservoir structure. This approach differs from traditional methods, as it can realistically reproduce the complex coupling mechanism between fracture spatial distribution, particle size distribution characteristics, and dynamic temperature and pressure evolution, thereby more accurately revealing the intrinsic driving laws of sand production initiation, development, and abrupt changes. This invention introduces the geological structural characteristics of the target reservoir into the reservoir simulation module, realizing spatially differentiated configuration of fracture and particle structures; in the environmental control module, it dynamically matches temperature and pressure regulation strategies according to the reservoir evolution stages, avoiding experimental distortion caused by control mismatch; in the process monitoring and coupling analysis module, through the temporal synchronization of multi-source response information and the identification of evolution paths, it accurately locates key response nodes for sand production, providing data support for sand production status identification and control. This invention not only improves the geological representativeness and process controllability of hydrate sand production experiments, but also provides theoretical basis and technical support for optimizing on-site mining schemes, designing sand control measures, and risk warning, and has significant engineering application value.

[0016] In another aspect, the present invention also proposes a method for testing hydrate sand production that couples fracture morphology, formation particles, and temperature and pressure conditions, comprising the following steps: A hydrate-simulated reservoir is constructed, and corresponding fracture structures and formation particle structures are configured in the hydrate-simulated reservoir. Experimental environmental conditions were applied to the hydrate simulated reservoir to cause the hydrates in the hydrate simulated reservoir to decompose and induce fluid transport and particle migration processes inside the reservoir. Acquire the fracture response information, particle response information, and sand production response information of the simulated hydrate reservoir during the hydrate decomposition process; Based on the fracture response information, particle response information, and sand production response information, the coupling relationship between fracture structure, formation particles, and experimental environmental conditions is analyzed, and the corresponding sand production evolution state is determined based on the coupling relationship. The experimental environmental conditions are adjusted according to the sand production evolution state to achieve dynamic simulation of the sand production process in hydrate reservoirs.

[0017] It is understandable that the above-mentioned experimental system and testing method for hydrate sand production under coupled fracture morphology, formation particles and temperature and pressure conditions have the same beneficial effects, and will not be elaborated here. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A structural block diagram of the experimental system for hydrate sand production under coupled fracture morphology, formation particles and temperature and pressure conditions provided in an embodiment of the present invention; Figure 2 The flowchart illustrates the hydrate sand production test method for coupled fracture morphology, formation particles, and temperature and pressure conditions provided in this embodiment of the invention. Detailed Implementation

[0020] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] See Figure 1 As shown in some embodiments of this application, this embodiment provides a hydrate sand production experimental system that couples fracture morphology, formation particles, and temperature and pressure conditions, including: The reservoir simulation module is configured to construct a hydrate simulated reservoir and configure corresponding fracture structures and formation particle structures in the hydrate simulated reservoir. The environmental control module is configured to apply experimental environmental conditions to the hydrate simulated reservoir, causing the hydrates in the hydrate simulated reservoir to decompose and inducing fluid transport and particle migration processes inside the reservoir. The process monitoring module is configured to acquire fracture response information, particle response information, and sand production response information of the hydrate simulated reservoir during the hydrate decomposition process; The coupling analysis module is configured to analyze the coupling relationship between fracture structure, formation particles and experimental environmental conditions based on the fracture response information, particle response information and sand production response information, and determine the corresponding sand production evolution state based on the coupling relationship. The state control module is configured to adjust the experimental environment conditions according to the sand production evolution state in order to achieve dynamic simulation of the sand production process of hydrate reservoirs.

[0022] It is understood that the hydrate sand production experimental system provided in this embodiment, which couples fracture morphology, formation particles, and temperature and pressure conditions, can flexibly adjust the configuration of fracture morphology and particle structure for target hydrate reservoirs with different geological characteristics. At the same time, it can match the corresponding temperature and pressure control strategy according to the dynamic evolution of the sand production process, thereby meeting the experimental needs of sand production mechanism research under different reservoir conditions and solving the technical problem that traditional experimental systems are difficult to reproduce the multi-factor coupling effect of real reservoirs.

[0023] Specifically, constructing a hydrate-simulated reservoir and configuring corresponding fracture structures and formation particle structures within the hydrate-simulated reservoir includes: Obtain the geological structural features corresponding to the target hydrate reservoir, and establish a simulated reservoir space model based on the geological structural features; Based on the heterogeneous structural features in the simulated reservoir space model, a fracture distribution structure matching the target reservoir is constructed inside the simulated hydrate reservoir. Based on the sedimentary characteristics corresponding to the target hydrate reservoir, the simulated particles are layered and configured so that different regions form corresponding particle composition structures. The fracture distribution structure is associated with the particle composition structure to form a hydrate simulated reservoir with spatial differences.

[0024] Understandably, geological structural characteristics include the measured fracture occurrence, aperture, fracture spacing, and spatial distribution range of the target reservoir. Sedimentary characteristics include the grain size distribution, grain roundness, and grain mineral composition of different strata within the target reservoir. Heterogeneous structural characteristics refer to the non-uniform spatial distribution of fractures and grains, such as the alternation of densely fractured and sparsely fractured zones, and the vertical stacking or lateral transition of coarse and fine grain layers. By converting the above geological parameters into quantifiable simulation input conditions, the structural complexity of the target reservoir can be reproduced with high fidelity in the experimental system, providing a realistic physical basis for subsequent coupled response analysis of hydrate decomposition and sand production processes.

[0025] Understandably, the construction process of hydrate simulated reservoirs must ensure the geometric matching and physical compatibility of fracture and particle structures in spatial location to avoid abnormal stress transmission or distorted fluid channels due to artificial mismatch. In practice, advanced molding technologies such as 3D printing, laser etching, or directional filling can be used to accurately reproduce the spatial distribution of fractures based on the simulated reservoir spatial model. A particle skeleton with the target gradation characteristics is then constructed layer by layer through screening, compaction, and cementation processes. Simultaneously, before hydrate formation, the simulated reservoir needs saturation control and initial stress loading to achieve pore pressure and effective stress states similar to the target reservoir, thereby ensuring the authenticity of mechanical response and migration behavior during subsequent decomposition.

[0026] Specifically, when applying experimental environmental conditions to the simulated hydrate reservoir, the following are included: Obtain the occurrence environment characteristics corresponding to the target hydrate reservoir, and determine the initial environmental state corresponding to the simulated hydrate reservoir based on the occurrence environment characteristics; According to the preset experimental conditions, temperature and pressure are adjusted on the hydrate simulated reservoir to change the thermodynamic state of the hydrate simulated reservoir. Based on the change process of the thermodynamic state, the hydrate decomposition process in the hydrate simulation reservoir is controlled, and a corresponding fluid transport state is formed inside the hydrate simulation reservoir. Based on the hydrate decomposition process and fluid transport state, the temperature regulation process and pressure regulation process are coordinated and controlled to form experimental environmental conditions that match the target hydrate reservoir exploitation process.

[0027] In this embodiment, the occurrence environment characteristics refer to the formation temperature, pore pressure, magnitude and direction of geostress in the original state of the target hydrate reservoir, as well as the thermal gradient characteristics of the seabed or terrestrial burial environment where the reservoir is located.

[0028] Understandably, the preset experimental conditions refer to the temperature and pressure change paths designed according to the preset experimental scheme, including the pore pressure reduction rate and gradient distribution during the depressurization mining process, as well as the temperature rise and heat transfer rate during the thermal mining process, or the temperature and pressure coordinated adjustment scheme during the depressurization-thermal mining process. These conditions are used to simulate the dynamic changes in the reservoir environment under different mining methods, thereby enabling targeted research on the response law of sand production behavior under different mining strategies.

[0029] Understandably, the application of experimental environmental conditions must fully consider the coupling relationship between hydrate phase equilibrium characteristics and reservoir mechanical stability. During temperature regulation, localized overheating should be avoided to prevent rapid hydrate decomposition leading to a sudden pressure surge or abrupt changes in particle structure. During pressure regulation, the depressurization rate must be controlled to prevent excessive pressure differentials from inducing unsteady fracture propagation or particle skeleton instability. To this end, the environmental control module can integrate high-precision temperature and pressure sensors with a feedback control system to monitor the simulated reservoir's internal state in real time and dynamically adjust heating power, cooling medium flow rate, or back pressure valve opening based on preset control strategies, achieving precise control of thermodynamic disturbance processes.

[0030] Specifically, when controlling the hydrate decomposition process in the simulated hydrate reservoir based on the change in the thermodynamic state, and when establishing a corresponding fluid transport state within the simulated hydrate reservoir, the process includes: Based on the thermodynamic state change information corresponding to the simulated hydrate reservoir, the hydrate decomposition region and its corresponding decomposition evolution process are determined. Based on the decomposition and evolution process, information on the changes in fluid products generated by hydrate decomposition is obtained, and the fluid pressure change state inside the simulated hydrate reservoir is determined. Based on the fluid pressure change state, fracture structure, and particle structure, the migration path of the fluid inside the simulated hydrate reservoir is analyzed. The experimental control process corresponding to the hydrate decomposition process is adjusted according to the migration path so that the fluid migration state inside the simulated hydrate reservoir corresponds to the target reservoir extraction process.

[0031] Understandably, based on the thermodynamic state change information corresponding to the simulated hydrate reservoir, the hydrate decomposition region and its corresponding decomposition evolution process are determined as follows: in-situ thermodynamic data are collected by temperature and pressure sensors distributed at different spatial locations in the simulated reservoir; real-time monitoring data are compared with the hydrate phase equilibrium curve to determine the phase stability of the hydrate at each location; then, the region that has entered the decomposition state is identified; and finally, the expansion direction and advancement rate of the decomposition region are tracked by combining monitoring data at different times to obtain complete information on the decomposition evolution process.

[0032] Understandably, based on the fluid pressure change state, fracture structure, and particle structure, the migration path of the fluid inside the simulated hydrate reservoir is analyzed: by combining the fluid conduction characteristics of the fractures with the permeability characteristics of different particle layers, the flow resistance of the fluid in different pore spaces and fracture channels is calculated. Combined with the fluid pressure gradient at different locations, the main channels for preferential fluid migration and subsequent diffusion paths are determined. At the same time, the fluid exchange relationship between fracture channels and particle pores is clarified, thereby obtaining the overall migration characteristics of the fluid inside the reservoir.

[0033] It is understandable that the experimental control process corresponding to the hydrate decomposition process is adjusted according to the migration path to make the fluid migration state inside the simulated reservoir corresponding to the target reservoir exploitation process. That is, according to the actual distribution of the fluid migration path, the temperature and pressure adjustment parameters are dynamically adjusted. For example, the depressurization rate is finely adjusted for high-permeability fracture zones with advanced decomposition, and the heating power is adjusted for dense particle zones with lagging decomposition. This allows the hydrate decomposition process and fluid production rate in different regions to match the evolution law in the actual exploitation process, avoiding abnormal flows that do not conform to the actual reservoir migration behavior.

[0034] Specifically, when coordinating the temperature regulation process and the pressure regulation process based on the hydrate decomposition process and fluid transport state, the following are included: The hydrate decomposition state information and fluid migration state information corresponding to the simulated hydrate reservoir are collected, and the current reservoir evolution stage is determined based on the hydrate decomposition state information and fluid migration state information; wherein, the reservoir evolution stage includes the hydrate decomposition initiation stage, the fluid migration stage, and the sand production evolution stage; The corresponding temperature and pressure regulation mode is determined according to the reservoir evolution stage, and the initial temperature state and initial pressure state are adjusted according to the temperature and pressure regulation mode. When the simulated hydrate reservoir is in the hydrate decomposition initiation stage, it is determined to be in the first temperature and pressure regulation mode, and the internal pressure of the simulated hydrate reservoir is reduced to control the rate of temperature change. When the simulated hydrate reservoir is in the fluid migration stage, it is determined to be in the second temperature and pressure regulation mode, and the pressure change amplitude and temperature compensation amount inside the simulated hydrate reservoir are adjusted to match the fluid migration process. When the simulated hydrate reservoir is in the sand production evolution stage, it is determined to be in the third temperature and pressure regulation mode, and the internal pressure change process and temperature control process of the simulated hydrate reservoir are adjusted to adapt to the particle migration process.

[0035] Understandably, the specific steps for determining the current reservoir evolution stage based on the hydrate decomposition state information and fluid migration state information are as follows: First, based on the real-time data collected by the process monitoring module regarding the hydrate decomposition rate, gas production, and dynamic changes in pore pressure, it is determined whether a hydrate phase transition has been triggered. When the temperature drop due to hydrate decomposition endothermic effect exceeds 0.5℃ and the gas production rate exceeds 5mL / min, the hydrate decomposition initiation stage is determined to have begun. Second, when the fluid pressure gradient reaches 0.05MPa / m and remains there for 10 minutes, and a stable flow signal is detected within the fracture channel, while the particle displacement is less than 0.1mm, the system is determined to be in the fluid migration stage. Finally, when the particle displacement exceeds 0.5mm, the cumulative solid particle production at the sand outlet exceeds 1g, or the number of acoustic emission events exceeds 50 times / min, the sand production evolution stage is confirmed to have begun. The criteria for each stage are combined with multi-source sensor data fusion analysis, and automatic identification and mode switching are achieved through preset state transition logic.

[0036] Understandably, in the first temperature and pressure regulation mode, the pressure is reduced slowly, with the pressure reduction rate controlled at 0.01–0.05 MPa / min, while maintaining a relatively constant temperature or controlling temperature fluctuations within ±0.2℃ to avoid rapid hydrate decomposition leading to localized stress concentration. In the second temperature and pressure regulation mode, the pressure change process is adjusted according to the fluid migration state. The pressure reduction is increased to 0.05–0.1 MPa / min in high-permeability areas, while low-permeability areas are gently heated, with the heating rate controlled not exceeding 0.1℃ / min, to achieve balanced fluid production. In the third temperature and pressure regulation mode, a step-by-step pressure reduction or pulsed pressure disturbance strategy is adopted, with the single pressure adjustment controlled at 0.05–0.2 MPa and the pressure holding time at 5–20 min, combined with temperature fine-tuning to control the temperature change range within ±0.5℃, in order to suppress excessive particle loosening and achieve dynamic simulation of the sand production process in hydrate reservoirs.

[0037] Specifically, when analyzing the coupling relationship between fracture structure, formation particles, and experimental environmental conditions based on the fracture response information, particle response information, and sand production response information, the following is included: The crack response information, particle response information, sand discharge response information, and corresponding experimental environmental conditions are synchronously mapped to establish a time-series response sequence of each response information as it changes during the experimental process. Based on the time-series response sequence, the sequential response relationship between fracture propagation, particle migration and sand production evolution is extracted to determine the evolution response path of the simulated hydrate reservoir from structural change to particle instability and then to sand production. Based on the evolution response path, the transmission relationship between fracture structure changes, formation particle migration and sand production behavior under different experimental conditions is identified, and the key response nodes affecting sand production evolution are determined. Based on the key response nodes, a coupled evolution relationship is constructed between fracture morphology, particle migration, and temperature and pressure response, and the sand production evolution state corresponding to the hydrate simulated reservoir is determined based on the coupled evolution relationship.

[0038] Understandably, the evolutionary response path involves identifying the triggering sequence and duration of various physical processes on the time axis using high-temporal-resolution multi-source monitoring data (such as changes in fracture opening, particle displacement vectors, sand production mass flow rate, and acoustic emission events). For example, fractures initially undergo micro-expansion under temperature and pressure disturbances, triggering local stress redistribution and fluid channel reconstruction. Subsequently, particles in adjacent areas migrate due to reduced effective stress or increased seepage drag. Ultimately, when particle migration accumulates to a critical level, it breaks through the reservoir outlet constraint, resulting in observable sand production. This path reveals a complete causal chain of "fracture structural response, particle mechanical instability, and sand production behavior manifestation," providing a temporal basis for clarifying the intrinsic driving mechanism of sand production.

[0039] Specifically, based on the evolutionary response path, when identifying the transmission relationship between fracture structure changes, formation particle migration, and sand production behavior under different experimental conditions, and determining the key response nodes affecting sand production evolution, the following are included: Based on the evolution response path, the crack propagation rate change characteristics, particle migration rate change characteristics, and sand discharge rate change characteristics are extracted respectively to determine the change stage corresponding to each response process; Based on the change stages corresponding to each response process, the sequential relationship between fracture structure changes, formation particle migration and sand production behavior is identified, and the response transmission process caused by temperature and pressure changes is determined. Based on the response propagation process, the state transition characteristics between different response stages are obtained, and the response transition nodes corresponding to crack propagation acceleration, enhanced particle migration, and sudden change in sand discharge rate are determined. Based on the response transition nodes, the key response nodes that affect the sand production evolution process due to changes in experimental environmental conditions are identified.

[0040] It is understandable that, based on the aforementioned evolutionary response path, extracting the characteristics of crack propagation rate variation, particle migration rate variation, and sand production rate variation, and determining the corresponding change stages for each response process, refers to: identifying the typical change patterns of each physical quantity during the evolution process through segmented feature analysis of the time-series response sequence. For example, the crack propagation rate may experience three stages: initial slow growth, mid-term accelerated propagation, and late-term stabilization. When the crack propagation rate is below 0.02 mm / min, it is determined to be in the initial slow growth stage; when the crack propagation rate increases to 0.02–0.1 mm / min and remains there for more than 5 minutes, it is determined to have entered the accelerated propagation stage; when the crack propagation rate change is less than 5% / min and remains there for more than 10 minutes, it is determined to have entered the stabilization stage.

[0041] The particle migration rate exhibits a latent period, a linear growth period, and a nonlinear surge period. When the particle migration rate is below 0.01 mm / min, it corresponds to the latent stage; when the particle migration rate reaches 0.01 to 0.05 mm / min, it enters the linear growth stage; when the particle migration rate exceeds 0.05 mm / min and the growth rate exceeds 50% of the previous stage, it is determined to enter the nonlinear surge stage.

[0042] The sand output rate typically exhibits three phases: no sand output, intermittent sand output, and sustained high output. A sand output rate below 0.1 g / min is considered a phase with no significant sand output; an output rate between 0.1 and 1 g / min with intermittent output is considered an intermittent sand output phase; and a sand output rate continuously exceeding 1 g / min for more than 5 minutes is considered a sustained high output phase. These phase divisions are determined based on the abrupt change in the slope of change, the second-order trend, and the statistical changes within a continuous time window.

[0043] Based on this, by cross-referencing the start and end times of each response process, the order and overlap between them can be clarified. For example, within 3 to 5 minutes after the crack propagation rate enters the acceleration stage, the particle migration rate begins to move from the latent stage to the linear growth stage, indicating that the crack structure change has a leading driving effect on particle instability; when the particle migration rate exceeds 0.05 mm / min and remains so for 2 minutes, the sand discharge rate shows its first jump within the following 30 to 60 seconds, increasing from less than 0.1 g / min to more than 0.5 g / min, reflecting that the accumulation of particle migration reaches a critical state and triggers macroscopic sand discharge.

[0044] Furthermore, by combining the changes in temperature and pressure control parameters, it is possible to trace the transmission of external disturbances through the crack-particle system and their impact on sand production behavior. For example, when the depressurization rate increases from 0.02 MPa / min to 0.08 MPa / min, the crack propagation rate shows a significant increase within 60–120 s, rising from 0.015 mm / min to 0.06 mm / min; subsequently, after 3–5 min, the particle migration rate increases from 0.01 mm / min to 0.04 mm / min, and within a 5–10 min time window, this leads to an increase in the sand production rate from intermittent to over 1 g / min.

[0045] Finally, by focusing the above analysis on the key nodes of response transformation, including the acceleration inflection point where the crack propagation rate changes from less than 0.02 mm / min to more than 0.1 mm / min, the overall migration critical point where the particle migration rate exceeds 0.05 mm / min, and the abrupt change point where the sand discharge rate changes from less than 0.1 g / min to more than 1 g / min, the key response windows that affect the evolution of sand discharge under experimental environmental conditions can be determined.

[0046] Specifically, determining the corresponding sand production evolution state based on the aforementioned coupling relationship includes: Based on the aforementioned coupling relationship, the response triggering relationship between changes in experimental environmental conditions and fracture structure response and formation particle migration is determined; Based on the aforementioned response triggering relationship, the continuous evolution process of crack propagation, particle instability, and sand production caused by temperature and pressure changes is identified; Based on the continuous evolution process, determine the state transition relationships corresponding to crack structure changes, particle migration, and sand discharge behavior during the current experiment. Based on the state transition relationship, the sand production evolution state corresponding to the hydrate simulated reservoir is determined.

[0047] Understandably, based on the aforementioned coupling relationship, clarifying the response triggering relationship between changes in experimental environmental conditions and fracture structure response and formation particle migration is achieved by analyzing the temporal correlation between temperature and pressure disturbance inputs and fracture and particle response outputs, thereby identifying the triggering effect of environmental condition changes on reservoir structural instability. For example, when the depressurization rate exceeds 0.05 MPa / min, if the fracture opening increases by more than 0.1 mm from its initial state within 60 s, and this fracture opening change occurs more than 2 min earlier than the particle displacement initiation time, then the pressure change is determined to be an effective triggering factor for the fracture response. Similarly, under stable pressure conditions, when the heating rate exceeds 0.1 °C / min, if the particle migration rate increases from below 0.01 mm / min to above 0.05 mm / min and remains there for more than 3 min, then the temperature disturbance is determined to be the dominant triggering factor for particle migration.

[0048] It is understandable that by cascading the continuously observed triggering events in chronological order, the complete evolutionary process driven by temperature and pressure changes can be reconstructed: In the initial stage, when the pressure decrease reaches more than 0.2 MPa, it triggers micro-expansion of cracks; subsequently, within 3–5 minutes, the crack opening increases from less than 0.05 mm to more than 0.2 mm, altering the local seepage channels; further, after 5–10 minutes, the particle migration rate increases from less than 0.01 mm / min to more than 0.05 mm / min, causing particles to transition from a stable state to a migrating state; finally, when the particle output per unit time exceeds 0.5 g / min, sand production begins to appear. This process reflects the cascade response relationship between temperature and pressure disturbances, crack evolution, particle migration, and sand production formation.

[0049] Understandably, based on the current response stage of each subsystem and their mutual coupling relationships, typical state transition relationships can be defined. For example, when the crack propagation rate reaches 0.02 mm / min or higher and continues to grow, while the particle displacement is less than 0.1 mm, the system is in a "structure-dominated" state; when the particle migration rate reaches 0.05 mm / min or higher, but the sand emission rate is still less than 0.5 g / min, the system is in a "transitional instability state"; when the sand emission rate continuously exceeds 1 g / min for more than 5 minutes, and the frequency of acoustic emission events exceeds 50 times / min, the system is determined to have entered a "strong sand emission evolution state".

[0050] Understandably, based on the above state transition relationship and combined with real-time monitoring data, the current evolution stage of the system can be dynamically determined. When the fracture response, particle migration and sand production response meet the corresponding state transition conditions, the current sand production evolution state of the hydrate simulated reservoir can be determined.

[0051] Specifically, adjusting the experimental environmental conditions according to the sand production evolution state includes: Based on the sand production evolution status, determine the current sand production evolution stage of the simulated hydrate reservoir, and obtain the environmental response requirements corresponding to the sand production evolution stage; Based on the environmental response requirements, determine the control direction corresponding to the experimental environmental conditions, and match and adjust the temperature control process and the pressure control process. When the hydrate simulated reservoir is in the particle migration enhancement stage, the pressure change amplitude is reduced according to the particle migration state, and the temperature control process is adjusted. When the simulated hydrate reservoir is in the rapid evolution stage of sand production, the pressure change path and temperature change process are adjusted according to the sand production evolution state. The experimental environmental conditions are updated based on the adjusted temperature and pressure regulation processes, and the response information corresponding to the hydrate simulated reservoir is continuously acquired.

[0052] Understandably, based on the identified sand production evolution state, its corresponding physical response characteristics are matched to clarify the current system's sensitivity and stability boundaries to temperature and pressure disturbances. For example, when the system is in the enhanced particle migration stage, if the monitored particle migration rate reaches 0.05 mm / min or higher, the crack propagation rate exceeds 0.08 mm / min, and the pore pressure drop rate exceeds 0.05 MPa / min, the system is determined to have entered a highly sensitive state. At this time, it is necessary to reduce the pressure change rate, adjusting the pressure drop rate from 0.08 MPa / min to 0.02 MPa / min to 0.03 MPa / min, while controlling the temperature change range to not exceed ±0.3℃, in order to mitigate particle instability caused by enhanced fluid drag.

[0053] When the system has entered the rapid evolution stage of sand production, if the sand production rate exceeds 1 g / min and lasts for more than 5 minutes, and the frequency of acoustic emission events exceeds 50 times / min, the control target will be adjusted to limit the sand production growth rate. At this time, a pressure stabilization platform will be used to maintain the pressure within ±0.05 MPa of the current value for 10 to 20 minutes, and the temperature change rate will be reduced to less than 0.05℃ / min to reduce the driving force for further decomposition of hydrates and avoid rapid destruction of the simulated reservoir structure.

[0054] Understandably, determining the direction of regulation requires considering both the historical performance and current trends of key response nodes. For example, when the particle migration rate is detected to be close to the critical threshold of 0.05 mm / min, and the crack conductivity increases by more than 30% from the initial state, preventative intervention is implemented in advance. The pressure reduction is adjusted from a single-stage 0.2 MPa to a step-by-step reduction, decreasing by 0.05 MPa each time and maintaining the pressure for 5 minutes. Simultaneously, local temperature regulation is applied in the dense particle region, reducing the temperature by 0.5–1°C to keep the particle migration process within a controllable range.

[0055] Furthermore, when the sand discharge rate rapidly increases from below 0.5 g / min to above 1 g / min, the system enters a strong response control mode. At this time, the depressurization rate is reduced to 0.01–0.02 MPa / min, and the outlet pressure is increased by 0.05–0.1 MPa through back pressure regulation to reduce the instantaneous scouring capacity of the fluid. At the same time, the temperature change range is controlled within ±0.2℃ to maintain the smooth progress of the hydrate decomposition process.

[0056] Understandably, after the updated experimental environmental conditions are applied as new input to the simulated reservoir, the system re-acquires information on fracture response, particle migration, and sand production response. The adjustment is considered effective when the following conditions are met: particle migration rate decreases to below 0.03 mm / min, sand production rate decreases to below 0.5 g / min, and fracture propagation rate stabilizes below 0.02 mm / min. If the particle migration rate continues to exceed 0.05 mm / min or the sand production rate exceeds 1 g / min, the temperature and pressure regulation process is restarted.

[0057] This forms a closed-loop control process of "sand production status identification - environmental requirements determination - temperature and pressure condition adjustment - response effect verification", enabling dynamic simulation of the sand production evolution process of hydrate reservoirs.

[0058] See Figure 2 As shown in some embodiments of this application, this embodiment provides a method for testing hydrate sand production that couples fracture morphology, formation particles, and temperature and pressure conditions, including the following steps: S100: Construct a hydrate simulated reservoir and configure corresponding fracture structures and formation particle structures in the hydrate simulated reservoir; S200: Apply experimental environmental conditions to the hydrate simulated reservoir to cause the hydrates in the hydrate simulated reservoir to decompose and induce fluid transport and particle migration processes inside the reservoir; S300: Obtain the fracture response information, particle response information, and sand production response information of the simulated hydrate reservoir during the hydrate decomposition process; S400: Based on the fracture response information, particle response information, and sand production response information, analyze the coupling relationship between fracture structure, formation particles, and experimental environmental conditions, and determine the corresponding sand production evolution state based on the coupling relationship. S500: Adjust the experimental environment conditions according to the sand production evolution state to achieve dynamic simulation of the sand production process of hydrate reservoirs.

[0059] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program goods. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program goods embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0060] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program goods according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0061] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0062] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A hydrate sand-producing experimental system that couples fracture morphology, formation particles, and temperature and pressure conditions, characterized in that, include: The reservoir simulation module is configured to construct a hydrate simulated reservoir and configure corresponding fracture structures and formation particle structures in the hydrate simulated reservoir. The environmental control module is configured to apply experimental environmental conditions to the hydrate simulated reservoir, causing the hydrates in the hydrate simulated reservoir to decompose and inducing fluid transport and particle migration processes inside the reservoir. The process monitoring module is configured to acquire fracture response information, particle response information, and sand production response information of the hydrate simulated reservoir during the hydrate decomposition process; The coupling analysis module is configured to analyze the coupling relationship between fracture structure, formation particles and experimental environmental conditions based on the fracture response information, particle response information and sand production response information, and determine the corresponding sand production evolution state based on the coupling relationship. The state control module is configured to adjust the experimental environment conditions according to the sand production evolution state in order to achieve dynamic simulation of the sand production process of hydrate reservoirs.

2. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 1, characterized in that, Constructing a hydrate-simulated reservoir and configuring corresponding fracture structures and formation particle structures within the hydrate-simulated reservoir includes: Obtain the geological structural features corresponding to the target hydrate reservoir, and establish a simulated reservoir space model based on the geological structural features; Based on the heterogeneous structural features in the simulated reservoir space model, a fracture distribution structure matching the target reservoir is constructed inside the simulated hydrate reservoir. Based on the sedimentary characteristics corresponding to the target hydrate reservoir, the simulated particles are layered and configured so that different regions form corresponding particle composition structures. The fracture distribution structure is associated with the particle composition structure to form a hydrate simulated reservoir with spatial differences.

3. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 2, characterized in that, When applying experimental environmental conditions to the hydrate simulated reservoir, the following are included: Obtain the occurrence environment characteristics corresponding to the target hydrate reservoir, and determine the initial environmental state corresponding to the simulated hydrate reservoir based on the occurrence environment characteristics; According to the preset experimental conditions, temperature and pressure are adjusted on the hydrate simulated reservoir to change the thermodynamic state of the hydrate simulated reservoir. Based on the change process of the thermodynamic state, the hydrate decomposition process in the hydrate simulation reservoir is controlled, and a corresponding fluid transport state is formed inside the hydrate simulation reservoir. Based on the hydrate decomposition process and fluid transport state, the temperature regulation process and pressure regulation process are coordinated and controlled to form experimental environmental conditions that match the target hydrate reservoir exploitation process.

4. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 3, characterized in that, When controlling the hydrate decomposition process in the simulated hydrate reservoir based on the change in the thermodynamic state, and when establishing a corresponding fluid transport state within the simulated hydrate reservoir, the process includes: Based on the thermodynamic state change information corresponding to the simulated hydrate reservoir, the hydrate decomposition region and its corresponding decomposition evolution process are determined. Based on the decomposition and evolution process, information on the changes in fluid products generated by hydrate decomposition is obtained, and the fluid pressure change state inside the simulated hydrate reservoir is determined. Based on the fluid pressure change state, fracture structure, and particle structure, the migration path of the fluid inside the simulated hydrate reservoir is analyzed. The experimental control process corresponding to the hydrate decomposition process is adjusted according to the migration path so that the fluid migration state inside the simulated hydrate reservoir corresponds to the target reservoir extraction process.

5. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 4, characterized in that, When coordinating the temperature regulation process and the pressure regulation process based on the hydrate decomposition process and fluid transport state, the following are included: The hydrate decomposition state information and fluid migration state information corresponding to the simulated hydrate reservoir are collected, and the current reservoir evolution stage is determined based on the hydrate decomposition state information and fluid migration state information; wherein, the reservoir evolution stage includes the hydrate decomposition initiation stage, the fluid migration stage, and the sand production evolution stage; The corresponding temperature and pressure regulation mode is determined according to the reservoir evolution stage, and the initial temperature state and initial pressure state are adjusted according to the temperature and pressure regulation mode. When the simulated hydrate reservoir is in the hydrate decomposition initiation stage, it is determined to be in the first temperature and pressure regulation mode, and the internal pressure of the simulated hydrate reservoir is reduced to control the rate of temperature change. When the simulated hydrate reservoir is in the fluid migration stage, it is determined to be in the second temperature and pressure regulation mode, and the pressure change amplitude and temperature compensation amount inside the simulated hydrate reservoir are adjusted to match the fluid migration process. When the simulated hydrate reservoir is in the sand production evolution stage, it is determined to be in the third temperature and pressure regulation mode, and the internal pressure change process and temperature control process of the simulated hydrate reservoir are adjusted to adapt to the particle migration process.

6. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 5, characterized in that, When analyzing the coupling relationship between fracture structure, formation particles, and experimental environmental conditions based on the fracture response information, particle response information, and sand production response information, the following is included: The crack response information, particle response information, sand discharge response information, and corresponding experimental environmental conditions are synchronously mapped to establish a time-series response sequence of each response information as it changes during the experimental process. Based on the time-series response sequence, the sequential response relationship between fracture propagation, particle migration and sand production evolution is extracted to determine the evolution response path of the simulated hydrate reservoir from structural change to particle instability and then to sand production. Based on the evolution response path, the transmission relationship between fracture structure changes, formation particle migration and sand production behavior under different experimental conditions is identified, and the key response nodes affecting sand production evolution are determined. Based on the key response nodes, a coupled evolution relationship is constructed between fracture morphology, particle migration, and temperature and pressure response, and the sand production evolution state corresponding to the hydrate simulated reservoir is determined based on the coupled evolution relationship.

7. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 6, characterized in that, Based on the aforementioned evolutionary response path, when identifying the transmission relationship between fracture structure changes, formation particle migration, and sand production behavior under different experimental conditions, and determining the key response nodes affecting sand production evolution, the following are included: Based on the evolution response path, the crack propagation rate change characteristics, particle migration rate change characteristics, and sand discharge rate change characteristics are extracted respectively to determine the change stage corresponding to each response process; Based on the change stages corresponding to each response process, the sequential relationship between fracture structure changes, formation particle migration and sand production behavior is identified, and the response transmission process caused by temperature and pressure changes is determined. Based on the response propagation process, the state transition characteristics between different response stages are obtained, and the response transition nodes corresponding to crack propagation acceleration, enhanced particle migration, and sudden change in sand discharge rate are determined. Based on the response transition nodes, the key response nodes that affect the sand production evolution process due to changes in experimental environmental conditions are identified.

8. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 7, characterized in that, When determining the corresponding sand production evolution state based on the aforementioned coupling relationship, the following are included: Based on the aforementioned coupling relationship, the response triggering relationship between changes in experimental environmental conditions and fracture structure response and formation particle migration is determined; Based on the aforementioned response triggering relationship, the continuous evolution process of crack propagation, particle instability, and sand production caused by temperature and pressure changes is identified; Based on the continuous evolution process, determine the state transition relationships corresponding to crack structure changes, particle migration, and sand discharge behavior during the current experiment. Based on the state transition relationship, the sand production evolution state corresponding to the hydrate simulated reservoir is determined.

9. The experimental system for hydrate sand production based on coupled fracture morphology, formation particles, and temperature and pressure conditions according to claim 8, characterized in that, When adjusting the experimental environmental conditions according to the sand production evolution state, the following are included: Based on the sand production evolution status, determine the current sand production evolution stage of the simulated hydrate reservoir, and obtain the environmental response requirements corresponding to the sand production evolution stage; Based on the environmental response requirements, determine the control direction corresponding to the experimental environmental conditions, and match and adjust the temperature control process and the pressure control process. When the hydrate simulated reservoir is in the particle migration enhancement stage, the pressure change amplitude is reduced according to the particle migration state, and the temperature control process is adjusted. When the simulated hydrate reservoir is in the rapid evolution stage of sand production, the pressure change path and temperature change process are adjusted according to the sand production evolution state. The experimental environmental conditions are updated based on the adjusted temperature and pressure regulation processes, and the response information corresponding to the hydrate simulated reservoir is continuously acquired.

10. A method for testing hydrate sand production coupled with fracture morphology, formation grain size, and temperature and pressure conditions, applied to the hydrate sand production experimental system coupled with fracture morphology, formation grain size, and temperature and pressure conditions as described in any one of claims 1-9, characterized in that, include: A hydrate-simulated reservoir is constructed, and corresponding fracture structures and formation particle structures are configured in the hydrate-simulated reservoir. Experimental environmental conditions were applied to the hydrate simulated reservoir to cause the hydrates in the hydrate simulated reservoir to decompose and induce fluid transport and particle migration processes inside the reservoir. Acquire the fracture response information, particle response information, and sand production response information of the simulated hydrate reservoir during the hydrate decomposition process; Based on the fracture response information, particle response information, and sand production response information, the coupling relationship between fracture structure, formation particles, and experimental environmental conditions is analyzed, and the corresponding sand production evolution state is determined based on the coupling relationship. The experimental environmental conditions are adjusted according to the sand production evolution state to achieve dynamic simulation of the sand production process in hydrate reservoirs.

Images