A coupled simulation structure and simulation device for hydrate reservoir formation

Abstract

The present application discloses a coupled simulation structure and a simulation device for hydrate reservoir formation. The simulation device includes a reaction experiment chamber, a coupled simulation structure, an environmental pressure control device, a gas transmission control device, a stability domain simulation device, a hydrate evolution observation device, a methane leakage detection device, and a data transmission control device. The coupled simulation structure includes a monoclinic sedimentary formation simulation structure, a sedimentary structure transition simulation structure, a reticulated fault simulation structure, and a faulted anticline simulation structure. The reticulated fault simulation structure is located at the fracture of the faulted anticline simulation structure, and the faulted anticline simulation structure is connected to the reticulated fault simulation structure. The monoclinic sedimentary formation simulation structure, the sedimentary structure transition simulation structure, the reticulated fault simulation structure, and the faulted anticline simulation structure all contain filled particles. The present application can be widely applied to the field of geological exploration technology.

Description

Technical Field

[0001] This application relates to the technical field of geological exploration, and particularly relates to a coupled simulation structure and simulation equipment for hydrate accumulation. Background Art

[0002] In nature, most of the marine natural gas hydrates are distributed in muddy or muddy siltstone reservoirs with a water depth exceeding 1000 meters. This type of hydrate belongs to a typical sediment-controlled hydrate reservoir. The hydrates are mostly in a "low saturation" state (usually with a saturation below 10%), and are generally considered to have no significant commercial exploration and development value. However, with the continuous deepening of hydrate exploration work, more and more high-saturation hydrate reservoirs have been discovered (the hydrate saturation is generally above 80%), and they have typical tectonic factor control characteristics, showing good commercial exploration and development potential.

[0003] Under the background of passive continental margins, tectonic activities are relatively weak. Under such conditions, the distribution of hydrates is mainly restricted by sedimentation, showing typical "diffusive" hydrate distribution characteristics. Although there are local fluid activities such as mud diapirs and gas chimneys, overall the fluid activities are weak and the deep gas supply flux is low, resulting in generally low hydrate saturation and low commercial exploration and development potential.

[0004] On the contrary, under the background of active continental margins, the plate subduction induces strong tectonic activities, promoting the large-scale development of tectonic faults and providing an efficient path for the migration of deep gas-bearing hydrothermal fluids. The high-flux deep gas-bearing hydrothermal fluids migrate to the shallow hydrate stability zone in a short time to form regional hydrate accumulations, creating favorable geological conditions for the formation of high-saturation "leakage-type" hydrate reservoirs. In addition, under the background of active continental margins, the plate subduction often causes the overall or local deformation of sedimentary strata, forming tectonic uplift areas or sedimentary depression areas. Correspondingly, the hydrostatic pressure of the overlying sedimentary strata will decrease or increase, thereby restricting the spatial distribution state of the stability zone by changing the pressure conditions and ultimately controlling the differential enrichment law of hydrates.

[0005] Generally speaking, compared with the hydrate accumulation mainly restricted by sedimentation under the background of passive continental margins, the hydrate accumulation process under the background of active continental margins is the result of the coupled action of tectonic-sedimentary elements, and has a synergistic relationship with the spatio-temporal dynamic evolution of the hydrate stability zone. The hydrate accumulation process and the ore body enrichment law are also more complex.

[0006] Regarding the active continental margin background, especially the relevant experimental simulation devices and methods for the gas hydrate accumulation process under the coupling of tectonic - sedimentary geological elements are relatively few. The existing experimental simulation devices and technical methods are difficult to effectively simulate the gas - bearing fluid migration law and the gas hydrate accumulation process under complex tectonic - sedimentary backgrounds, especially under the conditions of relatively high formation temperatures and large gas fluxes related to deep tectonic activities. There is a lack of effective control means for the coupling relationship between tectonic - sedimentary elements and their synergistic action process with the spatio - temporal evolution of the gas hydrate stability zone, resulting in certain deviations between the representativeness of the simulated geological background and the accuracy and systematicness of the simulated experimental data and the real geological situation.

[0007] Therefore, carrying out experimental simulations of the gas hydrate accumulation process under the active continental margin background and revealing the gas hydrate formation process and the high - saturation gas hydrate accumulation and enrichment mechanism under the coupling of tectonic - sedimentary elements have important scientific significance and practical value for serving gas hydrate resource evaluation and exploration and development. Summary of the Invention

[0008] To solve at least one of the above - mentioned technical problems, the present application provides a coupled simulation structure and a simulation device for gas hydrate accumulation, and the technical solutions adopted are as follows.

[0009] The coupled simulation structure for gas hydrate accumulation provided by the present application includes a monoclinic sedimentary formation simulation structure arranged obliquely, a sedimentary structure transition simulation structure arranged obliquely, a reticulated fault simulation structure, and a fault - anticline simulation structure. The monoclinic sedimentary formation simulation structure and the reticulated fault simulation structure are connected through the sedimentary structure transition simulation structure; the reticulated fault simulation structure is located at the fracture of the fault - anticline simulation structure, and the fault - anticline simulation structure is connected to the reticulated fault simulation structure; wherein, there are filling particles in the monoclinic sedimentary formation simulation structure, the sedimentary structure transition simulation structure, the reticulated fault simulation structure, and the fault - anticline simulation structure. The particle size of the filling particles in the sedimentary structure transition simulation structure is larger than that of the filling particles in the monoclinic sedimentary formation simulation structure and smaller than that of the filling particles in the reticulated fault simulation structure.

[0010] The present application has at least the following beneficial effects: In the coupled simulation structure, the monoclinic sedimentary formation simulation structure is used to simulate the morphological distribution of sedimentary formations in the continental margin area, the reticulated fault simulation structure is used to simulate the efficient fluid conduction channels formed by the tectonic rupture of sedimentary formations in the continental margin area due to plate subduction, the sedimentary structure transition simulation structure plays a role in turning and transitioning between the monoclinic sedimentary formation simulation structure and the reticulated fault simulation structure, and the fault - anticline simulation structure is used to simulate the sedimentary deformation of strata in the continental margin area due to tectonic activities.

[0011] In certain embodiments of the present application, the inner cavity of the monoclinic sedimentary formation simulation structure is divided into at least two layers of first chambers by a permeable partition, each of the first chambers contains the filling particles, and the particle size of the filling particles in each first chamber is different.

[0012] In certain embodiments of the present application, the reticular fault simulation structure includes at least two thermal fluid conducting structures, the thermal fluid conducting structures are arranged in the inner cavity of the reticular fault simulation structure, the thermal fluid conducting structure is arranged as a hollow columnar structure, and the inner cavity of the thermal fluid conducting structure has the filling particles.

[0013] In certain embodiments of the present application, the network fault simulation structure includes at least two resistance heaters, which are arranged in the inner cavity of the network fault simulation structure, and the resistance heaters heat the thermal fluid conducting structure.

[0014] In certain embodiments of the present application, the thermal fluid conducting structures in the network fault simulation structure extend in different directions and intersect to form a network structure.

[0015] In certain embodiments of the present application, the inner cavity of the fault anticline simulation structure is provided with at least two layers of second chambers, and each of the second chambers contains the filling particles.

[0016] In certain embodiments of the present application, the inclination angle of the monoclinic sedimentary stratum simulation structure is adjustable.

[0017] The simulation equipment for hydrate accumulation provided in the present application includes a reaction experiment chamber, a coupled simulation structure, an environmental pressure control device, a gas transmission control device, a stable domain simulation device, a hydrate evolution observation device, a methane leakage detection device and a data transmission control device. The coupled simulation structure is arranged in the inner cavity of the reaction experiment chamber; the environmental pressure control device is connected to the reaction experiment chamber, and the environmental pressure control device is used to inject liquid into the reaction experiment chamber and form a hydraulic environment; the gas transmission control device is connected to the network fault simulation structure and the fault anticline simulation structure; the stable domain simulation device includes a circulation pump, a constant temperature controller and a low-temperature water bath circulation structure, and the low-temperature water bath circulation structure is movably arranged in the monocline sedimentary formation simulation structure, and the circulation pump and the constant temperature controller are both connected to the low-temperature water bath circulation structure; the hydrate evolution observation device includes at least one sensor arranged in the monocline sedimentary formation simulation structure; the methane leakage detection device is connected to the reaction experiment chamber; and the data transmission control device is electrically connected to the environmental pressure control device, the gas transmission control device, the stable domain simulation device, the hydrate evolution observation device and the methane leakage detection device.

[0018] The present application has at least the following beneficial effects: The coupling simulation structure is arranged in the inner cavity of the reaction experimental chamber. The environmental pressure control device injects liquid into the inner cavity of the reaction experimental chamber to form a hydraulic environment, so as to control the pressure field conditions of the coupling simulation structure. The stable domain simulation structure arranges a low-temperature water bath circulation structure on the surface of the monoclinic sedimentary formation simulation structure, so as to control the temperature field conditions of the coupling simulation structure. The gas transmission control device injects gas into the mesh fault simulation structure and the fault anticline simulation structure, and is used to simulate the deep thermogenic gas supply generated by tectonic fluid diversion under the background of an active continental margin. The hydrate evolution observation device and the methane leakage detection device can monitor various parameters in the reaction experimental chamber in real time and feed them back to the data transmission control device in real time.

[0019] In some embodiments of the present application, the sensor is inserted into the monoclinic sedimentary formation simulation structure.

[0020] In some embodiments of the present application, the sensor of the hydrate evolution observation device includes at least one of a resistivity sensor, an acoustic wave sensor, a density sensor, and a shear strength sensor.

[0021] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following further demonstrates the present application in conjunction with the drawings and embodiments. It should be noted that the embodiments shown in the following drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0023] Figure 1 It is a schematic structural diagram of the simulation device.

[0024] Figure 2 It is a schematic structural diagram of the coupling simulation structure.

[0025] Figure 3 It is a schematic exploded view of the structure of the coupling simulation structure.

[0026] Figure 4 It is a schematic diagram of the position change of the low-temperature water bath circulation structure on the monoclinic sedimentary formation simulation structure.

[0027] Figure 5 It is a schematic structural diagram of the fault anticline simulation structure.

[0028] Figure 6 It is a schematic structural diagram of the stable domain simulation device.

[0029] Figure 7 It is a schematic structural diagram of the hydrate evolution observation device.

[0030] Reference numerals:

[0031] 1000, coupled simulation structure; 1100, monoclinic sedimentary formation simulation structure; 1200, sedimentary structure transition simulation structure; 1300, reticulate fault simulation structure; 1301, hot fluid diversion structure; 1302, electrical resistance heater; 1400, faulted anticline simulation structure;

[0032] 2000, reaction test chamber;

[0033] 3100, environmental pressure control device; 3200, gas transmission control device; 3300, hydrate evolution observation device; 3301, resistivity sensor; 3302, acoustic wave sensor; 3303, density sensor; 3304, shear strength sensor; 3400, methane leakage detection device; 3500, data transmission control device;

[0034] 4100, low-temperature water bath circulation structure; 4200, circulation pump; 4300, constant temperature controller; 4400, refrigeration water tank. Detailed implementation manners

[0035] The following combines with Figures 1 to 7 The embodiments of the present application are described in detail, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be construed as a limitation to the present application.

[0036] In the description of the present application, it should be understood that if terms such as "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present application.

[0037] In the description of the present application, the meaning of "several" is more than one, the meaning of "multiple" is more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the present number, and understandings such as "above", "below", "within", etc. include the present number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0038] In the description of this application, unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "linked" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] In the description of this application, when descriptions such as "one embodiment", "some embodiments", "one example", "some examples", "some embodiments", "illustrative embodiments", "examples", "specific examples", "some examples", etc. appear, it means that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0040] The explanations of relevant terms that may be mentioned in this application are as follows.

[0041] Hydrate: A hydrate is a mineral crystal formed by the combination of water molecules and gas molecules under low-temperature and high-pressure conditions, mainly occurring in marine environments or terrestrial permafrost zones, and is a clean energy source with great potential. The hydrate in this application specifically refers to methane hydrate in the marine environment.

[0042] Hydrate stability zone: Hydrates only exist stably under specific "low-temperature and high-pressure" conditions, and cannot form or decompose outside this range. The hydrate stability zone refers to the physical space range where hydrates stably aggregate under specific temperature and pressure conditions.

[0043] Hydrate reservoir: Refers to a hydrate accumulation area formed by the aggregation of natural gas hydrates under specific geological conditions, such as deep-sea sediments or terrestrial permafrost. The formation of hydrate reservoirs is affected by various geological factors, mainly including stability zone conditions, gas source conditions, reservoir space conditions, fluid migration conditions, and geological tectonic environments, etc. These geological factors interact with each other and jointly determine the formation, distribution, and enrichment characteristics of natural gas hydrates.

[0044] Hydrate saturation: Refers to the ratio of the hydrate volume to the volume of the sediment pore space, and is an important factor for measuring the exploration and development potential of hydrates. Usually, deposits with higher hydrate saturation have higher commercial development value.

[0045] Acoustic and electrical characteristics of hydrates: It refers to the distribution characteristics of hydrates in reservoirs reflected by geophysical records such as acoustic waves or electrical signals. In hydrate exploration, the spatial distribution state of hydrates is often inferred based on parameters such as resistivity, acoustic velocity, shear strength, and density. For the hydrate-free gas system, the higher the hydrate saturation, the higher the resistivity, acoustic velocity, shear strength, and density signals of the reservoir; while the gas layer has high resistivity, but the acoustic velocity, shear strength, and density signals are relatively low.

[0046] Leakage-type hydrates: Faults are generated at the bottom of the ocean due to tectonic activities or lateral extrusion deformation of sedimentary strata. Hydrocarbon gases seep upward along the faults and gush out in large quantities, and hydrates are stably formed in the fissures of sediments under suitable temperature and pressure conditions. Such hydrates are characterized by high grade, shallow burial, and concentrated distribution. They often occur in massive form and have relatively high saturation.

[0047] Diffusion-type hydrates: Under suitable temperature and pressure conditions, hydrocarbon gases combine with the pore water of surrounding sediments and gradually form hydrates in the sediment pores in a diffusive form. Its formation process is subtle and slow, and the action range is extensive. Such hydrates usually appear in muddy sedimentary layers, with relatively dispersed spatial distribution and low saturation.

[0048] Active continental margin: It refers to the area where the continental plate and the oceanic plate collide and squeeze each other, and the oceanic plate subducts beneath the continental plate. Geological activities in such areas are active, often accompanied by earthquakes, volcanic eruptions, and deep high-temperature gas-bearing hydrothermal fluid activities.

[0049] Passive continental margin: It refers to the area within the same rigid lithospheric plate where the continental plate and the oceanic plate have no strong interaction. The tectonic activities in the passive continental margin area are relatively calm, lacking frequent earthquakes and volcanic eruptions, and the deep high-temperature gas-bearing hydrothermal fluid activities are also weak.

[0050] Fluid conduction channels: In the geological environment, deep strata are often damaged due to tectonic activities or formation overpressure, forming a series of fluid migration channels. Formation fluids usually migrate along these channels to the shallow layer and hydrate accumulation occurs in areas with suitable temperature and pressure conditions.

[0051] Structural faults: It refers to the geological phenomenon that sedimentary strata are broken due to geological stress and significant relative displacement occurs along the fault plane. Structural faults usually have good fluid permeability and become the dominant channels for deep gas-bearing fluids to migrate to the shallow layer.

[0052] Faulted anticline: Under the action of tectonic activities, sedimentary strata are bent and deformed, arching upward to form an anticline shape, and due to fault activities, the deformed sedimentary strata are offset. This special structure creates favorable conditions for the migration and accumulation of fluids such as oil and natural gas, and is of great significance for the exploration of oil and gas and natural gas hydrate resources.

[0053] The present application relates to a coupled simulation structure 1000 for hydrate accumulation. The coupled simulation structure 1000 includes a monoclinic sedimentary formation simulation structure 1100, a sedimentary structure transition simulation structure 1200, a reticulated fault simulation structure 1300, and an anticlinal nose simulation structure 1400. The monoclinic sedimentary formation simulation structure 1100 and the reticulated fault simulation structure 1300 are connected by the sedimentary structure transition simulation structure 1200. The reticulated fault simulation structure 1300 is located at the fracture of the anticlinal nose simulation structure 1400, and the anticlinal nose simulation structure 1400 is connected to the reticulated fault simulation structure 1300.

[0054] The monoclinic sedimentary formation simulation structure 1100, the sedimentary structure transition simulation structure 1200, the reticulated fault simulation structure 1300, and the anticlinal nose simulation structure 1400 all have filling particles. Specifically, the filling particles are quartz sand particles or ceramic particles.

[0055] The present application fully considers the tectonic-sedimentary coupling process in the background of an active continental margin, and specifically designs functional modules such as the monoclinic sedimentary formation simulation structure 1100, the sedimentary structure transition simulation structure 1200, the reticulated fault simulation structure 1300, and the anticlinal nose simulation structure 1400. It conducts differential simulation analysis of deep tectonic fluid activities and shallow sediment lithology changes, and further realizes the effective simulation of the dynamic evolution process of hydrate formation and decomposition under complex geological backgrounds and changes in tectonic and sedimentary conditions.

[0056] The monoclinic sedimentary formation simulation structure 1100, the sedimentary structure transition simulation structure 1200, the reticulated fault simulation structure 1300, and the anticlinal nose simulation structure 1400 are both independent of each other and form a systematic and complete experimental simulation device system through structural connections between them.

[0057] The monoclinic sedimentary formation simulation structure 1100 is arranged obliquely. The monoclinic sedimentary formation simulation structure 1100 is located in the upper part of the coupled simulation structure 1000 and is used to simulate the morphological distribution of sedimentary formations in the continental margin area. Quartz sand particles or ceramic particles are used as filling particles inside the monoclinic sedimentary formation simulation structure 1100 to simulate the changes in reservoir structure and physical properties such as porosity and permeability caused by changes in sediment lithology and grain size rhythm in the real marine environment under the background of an active continental margin. On the other hand, the monoclinic sedimentary formation simulation structure 1100 can also be used to simulate the sedimentary rhythm changes caused by sediment progradation or retrogradation due to sea-level rise and fall, making the simulated sediment reservoir conditions more in line with the actual geological situation.

[0058] The sedimentary structure transition simulation structure 1200 is set to an elongated axis shape and is located in the middle of the coupled simulation structure 1000, playing a key role in the transition between the monoclinic sedimentary formation simulation structure 1100 and the reticulated fault simulation structure 1300. Quartz sand particles or ceramic particles are used as filling particles inside the sedimentary structure transition simulation structure 1200, which can better realize the function of the sedimentary structure transition simulation structure 1200 as a transition structure in the simulation experiment.

[0059] The reticulated fault simulation structure 1300 is arranged obliquely and is located at the lower part of the coupled simulation structure 1000. The reticulated fault simulation structure 1300 is used to simulate the efficient fluid conduction channels formed by the tectonic rupture of sedimentary formations due to plate subduction under the background of an active continental margin, and can simulate the significant control effect of tectonic activities on the deformation of sedimentary formations. Quartz sand particles or ceramic particles are used as filling particles in the reticulated fault simulation structure 1300 to simulate good connectivity of sedimentary reservoirs and fluid permeability, so as to fit the good fluid conduction ability of tectonic fault channels under real geological conditions. [[ID=,5]]

[0060] The fault anticline simulation structure 1400 is located at the lower part of the coupled simulation structure 1000, and the fault anticline simulation structure 1400 is used to simulate the sedimentary deformation of strata caused by tectonic activities under the background of an active continental margin.

[0061] In some embodiments, the inclination angle of the monoclinic sedimentary formation simulation structure 1100 is adjustable to fit the specific conditions of the dip angle of sedimentary formations in different continental margin areas or different geological backgrounds.

[0062] Specifically, the sedimentary structure transition simulation structure 1200 is set as an elongated axis structure arranged horizontally, and the monoclinic sedimentary formation simulation structure 1100 uses the sedimentary structure transition simulation structure 1200 as a rotating shaft, so that the inclination angle of the monoclinic sedimentary formation simulation structure 1100 relative to the horizontal plane can be adjusted. Further, the inclination angle of the monoclinic sedimentary formation simulation structure 1100 can be adjusted automatically or manually.

[0063] In some embodiments, the particle size of the filling particles in the sedimentary structure transition simulation structure 1200 is larger than the particle size of the filling particles in the monoclinic sedimentary formation simulation structure 1100 and smaller than the particle size of the filling particles in the reticulated fault simulation structure 1300. This ensures that the porosity and permeability of the simulated reservoir in the sedimentary structure transition simulation structure 1200 are between those of the monoclinic sedimentary formation simulation structure 1100 and the reticulated fault simulation structure 1300, making the reservoir simulation environment closer to the real geological environment under the background of an active continental margin.

[0064] In some embodiments, to meet the experimental simulation requirements of multiple geological scenarios, the inner cavity of the monocline sedimentary formation simulation structure 1100 is divided into at least two layers of first chambers by a permeable partition, and each first chamber is filled with particles.

[0065] Furthermore, the filling particles in each first chamber have different particle sizes.

[0066] In some embodiments, the network fault simulation structure 1300 includes at least two thermal fluid drainage structures 1301, and the thermal fluid drainage structures 1301 simulate the dominant drainage channels when the gas-containing fluid in the deep formation migrates to the shallow layer.

[0067] Specifically, the thermal fluid conducting structure 1301 is arranged in the inner cavity of the network fault simulation structure 1300 . The thermal fluid conducting structure 1301 is arranged as a hollow columnar structure. The inner cavity of each thermal fluid conducting structure 1301 is filled with particles.

[0068] Furthermore, the network fault simulation structure 1300 includes at least two resistance heaters 1302, which are arranged in the thermal fluid conducting structure 1301. The resistance heaters 1302 heat the thermal fluid conducting structure 1301, thereby effectively simulating the heat transfer effect in the process of deep gas-containing fluid being conducted to the shallow layer, thereby realizing an effective simulation of the migration process of high-temperature gas-containing fluid from deep sources driven by tectonic activities under real geological conditions.

[0069] In some examples, the resistance heater 1302 is embedded in the side wall of the thermal fluid conducting structure 1301 to improve thermal conductivity.

[0070] It should be noted that the resistance heater 1302 can accurately simulate and control the formation temperature field under different tectonic fluid activity conditions in the active continental margin background by adjusting the heating power.

[0071] In some embodiments, the inner cavity of the fault anticline simulation structure 1400 is provided with at least two layers of second chambers, and each second chamber is filled with particles.

[0072] Furthermore, the particle sizes of the filling particles in each second chamber are different.

[0073] In some examples, the fault anticline simulation structure 1400 and the reticular fault simulation structure 1300 are detachably connected, so that the fault anticline simulation structure 1400 and the reticular fault simulation structure 1300 can not only be connected to form a combined structure, but also be disassembled into independent modules.

[0074] The coupled simulation structure 1000 designed in this application for the special geological background of active continental margins highlights the restrictive effect of deep tectonic activities on the migration of gas-bearing fluids and the formation and evolution of hydrates, making the simulation conditions closely approximate the true geological situation of the seabed strata and improving the simulation similarity.

[0075] This application relates to a simulation device for hydrate accumulation. The simulation device focuses on the dynamic accumulation and evolution process of hydrates under the background of active continental margins, which is of great significance for revealing the formation and evolution mechanism of hydrates and the law of high-saturation hydrate accumulation in the background area of active continental margins.

[0076] The simulation device includes a reaction experiment chamber 2000, a coupled simulation structure 1000, an environmental pressure control device 3100, a gas transmission control device 3200, and a stable domain simulation device. The coupled simulation structure 1000 is as described above. The coupled simulation structure 1000 is disposed in the inner cavity of the reaction experiment chamber 2000. The environmental pressure control device 3100 is connected to the reaction experiment chamber 2000. The gas transmission control device 3200 is connected to the mesh fault simulation structure 1300 and the fault anticline simulation structure 1400. The environmental pressure control device 3100 is used to inject liquid into the reaction experiment chamber 2000 to form a hydraulic environment. The gas transmission control device injects gas into the mesh fault simulation structure 1300 and the fault anticline simulation structure 1400.

[0077] The simulation device includes a hydrate evolution observation device 3300 and a methane leakage detection device 3400. The hydrate evolution observation device 3300 is connected to the monoclinic sedimentary formation simulation structure 1100. The methane leakage detection device 3400 is connected to the reaction experiment chamber 2000.

[0078] It should be noted that the simulation device includes a data transmission control device 3500, and the data transmission control device 3500 is electrically connected to the environmental pressure control device 3100, the gas transmission control device 3200, the stable domain simulation device, the hydrate evolution observation device 3300, and the methane leakage detection device 3400.

[0079] As the key bearing structure of the simulation device, the reaction experiment chamber 2000 is designed with a steel body cavity structure. The pressure bearing range of the steel body cavity structure of the reaction experiment chamber 2000 is 15 MPa to 30 MPa, corresponding to the simulated water depth range of 1500 meters to 3000 meters. It can simulate the hydrostatic pressure environment of the hydrate occurrence area, provide experimental simulation conditions close to the real geological scenario, and help ensure the accuracy and reliability of the experimental results.

[0080] The environmental pressure control device 3100 is used to regulate the pressure inside the reaction test chamber 2000, set key parameters such as reaction start pressure and termination pressure, etc., to achieve effective regulation of the environmental pressure, and simulate the formation pressure under the real marine environment. The environmental pressure control device 3100 can simulate the process of hydrostatic pressure change caused by local uplift and subsidence of the formation due to tectonic activities under the background of an active continental margin, and can also simulate the impact on the hydrostatic pressure of the sedimentary formation caused by sea-level rise or fall under periodic climate change conditions.

[0081] In the specific control mode of the environmental pressure, mainly by injecting water into the reaction test chamber 2000 to form a simulated hydraulic environment, the initial regulation of the environmental pressure of the real formation environment is achieved. In addition, the environmental pressure control device 3100 is equipped with valves for the water pipes, and by controlling the opening and closing degree of the valves, the further precise control of the simulated environmental pressure is realized. It can be understood that the valves are set as automatic valves, and the data transmission control device 3500 can precisely control the opening and closing of the valves.

[0082] The gas transmission control device 3200 is used to supply gas to the coupled simulation structure 1000. The main gas component is methane, and ethane, propane, butane and other multi-carbon heavy hydrocarbon gases with a set proportion can also be mixed according to the experimental needs, which is used to simulate the deep thermogenic gas supply caused by tectonic fluid drainage under the background of an active continental margin.

[0083] The gas transmission control device 3200 is respectively connected to the reticulated fault simulation structure 1300 and the faulted anticline simulation structure 1400 through gas drainage branches, and each gas drainage branch is provided with a valve for controlling the gas flow rate. The data transmission control device 3500 controls the opening and closing degree of the valves to set the gas flow rate parameters of the reticulated fault simulation structure 1300 or the faulted anticline simulation structure 1400, and realizes the precise simulation and regulation of the gas migration rate or flux of different simulation structures.

[0084] Furthermore, in order to simulate the case where the gas migration rate or gas flux in the reticulated fault simulation structure 1300 is greater than that in the faulted anticline simulation structure 1400 under the real geological background, the gas flow rates entering the reticulated fault simulation structure 1300 and the faulted anticline simulation structure 1400 are controlled to be different.

[0085] The stability domain simulation device is mainly used to control the temperature environment of the coupled simulation structure 1000. The purpose is to simulate the formation temperature field environment of the hydrate enrichment area under real geological conditions, and provide temperature conditions close to the real geological environment for the study of hydrate accumulation and evolution.

[0086] Specifically, the stability region simulation device includes a low-temperature water bath circulation structure 4100, and the low-temperature water bath circulation structure 4100 is disposed in the monoclinic sedimentary formation simulation structure 1100. The low-temperature water bath circulation structure 4100 is arranged on the surface of the monoclinic sedimentary formation simulation structure 1100, and the low-temperature water bath circulation structure 4100 can effectively simulate the stability region space of the hydrate reservoir.

[0087] Further, the low-temperature water bath circulation structure 4100 is sleeved on the outer side of the monoclinic sedimentary formation simulation structure 1100, and the monoclinic sedimentary formation simulation structure 1100 penetrates through the low-temperature water bath circulation structure 4100, so that the low-temperature water bath circulation structure 4100 wraps around the four side surfaces of the monoclinic sedimentary formation simulation structure 1100.

[0088] It can be understood that the stability region simulation device further includes a circulation pump 4200, a constant temperature controller 4300, and a refrigeration water tank 4400. The circulation pump 4200, the constant temperature controller 4300, and the refrigeration water tank 4400 are all connected to the low-temperature water bath circulation structure 4100. The refrigeration water tank 4400 stores a refrigerant. Under the power transmission of the circulation pump 4200, the refrigerant is transported to the low-temperature water bath circulation structure 4100 and can realize circulating flow.

[0089] The low-temperature water bath circulation structure 4100 is movably disposed on the monoclinic sedimentary formation simulation structure 1100, so that the low-temperature water bath circulation structure 4100 can move on the surface of the monoclinic sedimentary formation simulation structure 1100, thereby changing the relative position between the low-temperature water bath circulation structure 4100 and the monoclinic sedimentary formation simulation structure 1100, and realizing flexible regulation of the spatial distribution of the hydrate stability region.

[0090] At least one guiding structure is provided on the surface of the monoclinic sedimentary formation simulation structure 1100, and the low-temperature water bath circulation structure 4100 is movably connected to the guiding structure, so as to facilitate the low-temperature water bath circulation structure 4100 to move along the guiding structure to adjust its position on the surface of the monoclinic sedimentary formation simulation structure 1100, and realize effective adjustment of the spatial distribution of the hydrate stability region.

[0091] Further, the guiding structure is set as a slide rail or a slide groove, and the low-temperature water bath circulation structure 4100 is movably connected to the guiding structure through rollers or sliders.

[0092] The hydrate evolution observation device 3300 is used for monitoring the formation and decomposition behaviors of hydrates in the monoclinic sedimentary formation within the hydrate stability region. The hydrate evolution observation device 3300 includes at least one sensor disposed in the monoclinic sedimentary formation simulation structure 1100. The main function of the hydrate evolution observation device 3300 is to monitor the distribution of hydrates and free gas in the simulated reservoir and their evolution relationship.

[0093] Specifically, the sensors of the hydrate evolution observation device 3300 include at least one of a resistivity sensor 3301, an acoustic wave sensor 3302, a density sensor 3303, and a shear strength sensor 3304. Within the hydrate stability zone, when alkane gas combines with water to form hydrates, there are differential changes in the environmental monitoring signals, manifested as an increase in the resistivity, acoustic wave, shear strength, and density monitoring signals. When the hydrate stability zone undergoes adjustment changes, causing the hydrates to decompose into gas, the acoustic wave, shear strength, and density monitoring signals will become smaller, and the resistivity signal generally remains stable. These sensors send the monitoring signals to the data transmission control device 3500 for real-time data processing and analysis to generate key hydrate reservoir simulation parameters such as porosity and saturation, enabling real-time response and recording of the physical property changes in the reservoir during the hydrate evolution process.

[0094] The sensors of the hydrate evolution observation device 3300 are inserted into the monoclinic sedimentary formation simulation structure 1100 so that the sensors can have reservoir physical property monitoring points at different depths of the simulated reservoir. Through these monitoring points, the sensors of the hydrate evolution observation device 3300 can more accurately obtain the physical property parameter data of hydrates and free gas at different spatial positions in the simulated reservoir within the hydrate stability zone and provide real-time feedback to the data transmission control device 3500 for in-depth understanding of the evolution process and distribution law of the hydrate system in the simulated reservoir.

[0095] The methane leakage detection device 3400 is set at the top of the reaction experiment chamber 2000 and on the upper side of the coupling simulation structure 1000. The methane leakage detection device 3400 includes a methane concentration sensor probe for monitoring the dynamic evolution process of hydrates, especially the possible methane gas leakage during the hydrate decomposition process. Moreover, the methane leakage detection device 3400 can transmit the monitoring data to the data transmission control device 3500 in real time.

[0096] Under the background of the inclined sedimentary formation in the continental margin area, the decomposition of hydrates first occurs at the top boundary position of the stability zone, so methane gas leakage is also most likely to occur at this position. Based on this, the methane leakage detection device 3400 is set near the top boundary position of the stability zone, that is, the methane leakage detection device 3400 is set on the upper side of the coupling simulation structure 1000 to accurately monitor the methane concentration in the simulated water body.

[0097] The methane leakage detection device 3400 and the hydrate evolution observation device 3300 complement each other. The methane leakage detection device 3400 is mainly used for detecting the methane concentration in the water body of the reaction experimental chamber 2000, and the hydrate evolution observation device 3300 is mainly used for observing the occurrence state and evolution behavior of hydrates and free gas in the simulated hydrate reservoir (i.e., the monoclinic sedimentary formation simulation structure 1100). The methane leakage detection device 3400 and the hydrate evolution observation device 3300 jointly construct a comprehensive three-dimensional monitoring network for the dynamic evolution of hydrates at different spatial positions inside the reaction experimental chamber 2000, accurately recording the evolution behavior of hydrates in real time, and providing comprehensive, systematic, and real-time experimental simulation data support for exploring the dynamic evolution law of the whole process of hydrate formation, decomposition, and leakage under the background of the active continental margin.

[0098] The data transmission control device 3500 is the total command system for the program control, digital signal transmission, and feedback of the simulation device. The data transmission control device 3500 can meet the requirements of real-time signal communication and instruction coordination, and can achieve the automatic start control of the simulation device, efficient data transmission and feedback signal instructions, and real-time presentation of data information and completion of dynamic analysis.

[0099] In terms of function implementation, the data transmission control device 3500 adjusts the environmental pressure control device 3100 to set the starting pressure of the reaction experimental chamber 2000 and make the pressure reach the set value, completing the precise regulation of the pressure conditions of the reaction experimental chamber 2000.

[0100] The data transmission control device 3500 digitally and precisely regulates the gas transmission control device 3200 by setting the gas supply flow rate, effectively controlling the gas flow rate and methane flux entering the coupled simulation structure 1000.

[0101] The data transmission control device 3500 realizes the effective regulation and simulation of the high-temperature heat flow field environment caused by the simulated deep gas-bearing fluid activity by regulating the heating power of the resistance heater 1302 of the hot fluid diversion structure 1301.

[0102] The data transmission control device 3500 coordinates with the stability domain simulation device and the environmental pressure control device to dynamically adjust the temperature field and pressure field conditions of the stability domain based on the simulated environmental changes. According to the geological condition differences, by dynamically adjusting the environmental simulation parameters such as the temperature field and pressure field on the coupled simulation structure 1000, it realizes the precise simulation and autonomous regulation of the spatial distribution state of different hydrate stability domains under the background of the active continental margin.

[0103] The data transmission control device 3500 realizes the monitoring and real-time feedback of parameter signals such as methane concentration, resistivity, shear strength, acoustic velocity, and density in the simulation experiment by associating the hydrate evolution observation device 3300 and the methane leakage detection device 3400, and realizes the real-time monitoring and recording of the changes in reservoir physical properties during the hydrate evolution process.

[0104] It should be noted that the simulation device designed in this application realizes the experimental simulation of the formation and decomposition process of hydrates under the background of an active continental margin, especially under the coupled action of deep tectonic activities and shallow sedimentation, with the coordinated changes in the behavior of gas-bearing fluids and the stability domain. Through the coordinated cooperation of various components in the simulation device, multi-dimensional and systematic real-time dynamic monitoring of the dynamic evolution process of hydrates under the background of an active continental margin is achieved, providing an experimental simulation basis and an effective technical path for revealing the formation mechanism and enrichment law of hydrates, serving the drilling deployment and exploitation strategy formulation of high-saturation hydrates.

[0105] The simulation device of this application has at least the following beneficial effects.

[0106] First, multi-dimensional coordination:

[0107] The stability domain simulation device and the environmental pressure control device are closely coordinated to achieve synchronous and coordinated regulation of the simulated reservoir environment, temperature field, and pressure field. In terms of geological structure, effective coupling of the functions of simulating deep tectonic activities and shallow formation sedimentation is achieved, and the restrictive effects of tectonic activities on the migration of gas-bearing fluids and hydrate evolution are analyzed. In terms of monitoring, comprehensive three-dimensional monitoring of the hydrate evolution behavior at different spatial positions in the simulated hydrate reservoir and simulated water body is achieved, providing an effective path for in-depth study of the hydrate accumulation and evolution mechanism.

[0108] Second, adaptability to multiple working conditions:

[0109] The simulation device focuses on the special geological background of an active continental margin, and its coupling simulation structure has diverse functional modules such as a monoclinic sedimentary formation simulation structure, a sedimentary structure transition simulation structure, a reticulated fault simulation structure, and a faulted anticline simulation structure. These simulation structures can flexibly adjust parameters such as pressure and temperature of the simulation according to different geological or working conditions, and differentially control the changes in parameters such as the dip angle of the simulated sedimentary formation, the fluid activity rate, and the lithology of the sediment, making the simulation experiment closely fit the actual underground geological conditions and effectively improving the accuracy and reliability of the simulation results.

[0110] Third, precise measurement of multiple parameters:

[0111] The hydrate evolution observation device and the methane leakage detection device constitute a multi-parameter dynamic monitoring system for hydrates, which can record in real time and accurately the key parameters such as resistivity, shear strength, acoustic velocity, and density of the simulated hydrate reservoir at different hole positions during the simulation experiment. The monitored parameters are interrelated and cross-validated, effectively avoiding the limitations of single-parameter monitoring, achieving effective discrimination of monitoring errors, and providing comprehensive, systematic, and reliable experimental simulation data support for the study of the dynamic evolution law of the whole process of hydrate formation, decomposition, and leakage under the background of active continental margins.

[0112] The embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A coupled simulation structure for hydrate accumulation, characterized by: include Simulated structure of obliquely arranged monocline sedimentary strata; Transitional mimic structures of obliquely arranged sedimentary structures; A network fault simulation structure, wherein the monocline sedimentary stratum simulation structure and the network fault simulation structure are connected via the sedimentary structure transition simulation structure; a fault anticline simulation structure, wherein the network fault simulation structure is located at a fracture of the fault anticline simulation structure, and the fault anticline simulation structure is connected to the network fault simulation structure; The monocline sedimentary stratum simulation structure, the sedimentary structure transition simulation structure, the network fault simulation structure and the fault anticline simulation structure all have filling particles, and the particle size of the filling particles in the sedimentary structure transition simulation structure is larger than the particle size of the filling particles in the monocline sedimentary stratum simulation structure, and smaller than the particle size of the filling particles in the network fault simulation structure; The reticular fault simulation structure includes at least two thermal fluid conducting structures, which are arranged in the inner cavity of the reticular fault simulation structure. The thermal fluid conducting structures are arranged as hollow columnar structures, and the inner cavities of the thermal fluid conducting structures are filled with the filling particles.

2. The coupled simulation structure for hydrate accumulation according to claim 1, characterized in that: The inner cavity of the monoclinic sedimentary formation simulation structure is divided into at least two layers of first chambers by a permeable partition. Each of the first chambers contains the filling particles, and the particle sizes of the filling particles in each of the first chambers are different.

3. The coupled simulation structure for hydrate accumulation according to claim 1, characterized in that: The network fault simulation structure includes at least two resistance heaters, which are arranged in the inner cavity of the network fault simulation structure and heat the thermal fluid conducting structure.

4. The coupled simulation structure for hydrate accumulation according to claim 1 or 3, characterized in that: The thermal fluid conducting structures in the network fault simulation structure extend in different directions and intersect to form a network structure.

5. The coupled simulation structure for hydrate accumulation according to claim 1, characterized in that: The inner cavity of the fault anticline simulation structure is provided with at least two layers of second chambers, and each of the second chambers contains the filling particles.

6. The coupled simulation structure for hydrate accumulation according to claim 1, characterized in that: The inclination angle of the monoclinic sedimentary stratum simulation structure is adjustable.

7. A hydrate accumulation simulation device, characterized by: include Reaction test chamber; The coupling simulation structure according to any one of claims 1 to 6, wherein the coupling simulation structure is arranged in the inner cavity of the reaction test chamber; An environmental pressure control device, the environmental pressure control device is connected to the reaction experiment chamber, and the environmental pressure control device is used to inject liquid into the reaction experiment chamber and form a hydraulic environment; a gas transmission control device, the gas transmission control device connecting the network fault simulation structure and the fault anticline simulation structure; A stable domain simulation device, comprising a circulation pump, a constant temperature controller, and a low-temperature water bath circulation structure, wherein the low-temperature water bath circulation structure is movably disposed on the monoclinic sedimentary formation simulation structure, and the circulation pump and the constant temperature controller are both connected to the low-temperature water bath circulation structure; a hydrate evolution observation device, the hydrate evolution observation device comprising at least one sensor disposed in the monoclinic sedimentary formation simulation structure; a methane leakage detection device connected to the reaction test chamber; A data transmission control device is electrically connected to the environmental pressure control device, the gas transmission control device, the stability domain simulation device, the hydrate evolution observation device and the methane leakage detection device.

8. The hydrate accumulation simulation device according to claim 7, characterized in that: The sensor is inserted into the monocline sedimentary stratum simulation structure.

9. The hydrate accumulation simulation device according to claim 7 or 8, characterized in that: The sensor of the hydrate evolution observation device includes at least one of a resistivity sensor, an acoustic wave sensor, a density sensor and a shear strength sensor.

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