An experimental method for characterizing and inverting a fractured reservoir dominant path.

Abstract

This application discloses an experimental method for a fractured reservoir dominant path characterization and inversion experimental system. The experimental system and the provided fractured reservoir construction method and data acquisition method can recreate the heat exchange scenario between underground fractured fluids and geothermal reservoirs. The experimental system and implementation path of this invention provide a practical experimental operation process. By carrying out the complete process of "collecting the data required to realize the inversion of internal information of fractured reservoirs" within the experimental system, data acquisition methods and inversion methods under different geothermal environments and fractured reservoir environments can be continuously explored with lower time and economic costs. Through a large amount of experimental data, the inversion technology can be continuously improved, thereby applying mature theories to guide actual geothermal resource exploration. It can simulate the inversion of large-scale geothermal reservoir fracture network distribution information and provide an inversion theoretical basis for actual geothermal field investigation.

Description

Technical Field

[0001] This invention belongs to the field of information inversion in fractured reservoirs, and specifically relates to an experimental method for a fractured reservoir dominant path characterization and inversion experimental system. Background Technology

[0002] my country possesses abundant deep geothermal resources, which offer significant advantages over wind and solar energy, including stability and lack of geographical limitations, making them strategically important for achieving the "dual carbon" (carbon dioxide, carbon sequestration, and carbon emissions) goals. Both the "14th Five-Year Plan for Renewable Energy Development" and the "Opinions on Promoting the Development and Utilization of Geothermal Energy" issued by the National Energy Administration encourage the active utilization of medium-deep geothermal energy. Before undertaking geothermal resource development projects, it is often necessary to determine geothermal resource information and reservoir parameters to ensure the quality and reserves of geothermal resources in the target area. According to relevant literature, approximately 35% of geothermal development projects are suspended or terminated due to reservoir quality issues, ranking first among all reasons. Therefore, to ensure the rational development and efficient utilization of geothermal resources, it is essential to first assess the key parameters of the geothermal reservoir. Due to the constraints of the geothermal reservoir environment, the internal structure is often complex, exhibiting high temperature and pressure, making fracture channel inversion difficult. Currently, mainstream microseismic survey technology can only serve as a basis for judging the internal flow of the reservoir and cannot quantitatively describe the morphology, location, and size of fractures within the reservoir. Therefore, further research is needed on methods for effectively inverting geothermal reservoir parameters.

[0003] Accurate inversion of geothermal reservoir parameters first requires the collection of geothermal state or geological structure information from the surrounding area, which serves as the basis for inverting parameters of unknown fractured reservoirs. For the required monitoring data, the relationship between the data and reservoir parameters needs to be explored to further assess the quality of geothermal resources. Therefore, ensuring the usability and validity of the data is a task that requires repeated verification. Conducting high-temperature rock inversion experiments allows for further optimization of experimental schemes based on previous experimental platforms, exploring more complex and variable geothermal reservoir parameter inversion methods, and ultimately providing valuable technical reference for practical geothermal exploration work.

[0004] Therefore, how to design an inversion system and method that can realize more complex and varied geothermal reservoir parameters is a technical problem to be solved. Summary of the Invention

[0005] Therefore, it is necessary to provide an experimental method for characterizing and inverting the dominant path of fractured reservoirs to address the existing problems.

[0006] This application discloses an experimental method for a fractured reservoir dominant path characterization and inversion experimental system. The fractured reservoir dominant path characterization and inversion experimental system includes a controllable heating platform (1), a fractured reservoir model (2), a first temperature acquisition unit (3), a second temperature acquisition unit (4), a third temperature acquisition unit (5), a peristaltic water pump (6), a first water tank (7), a second water tank (8), and a heat insulation layer (9). The experimental method includes the following steps:

[0007] S11: Obtain parameter data of fractured reservoir model (2), the parameter data including density, thermal conductivity, specific heat capacity and external geometric parameters of different regions;

[0008] S12: Heat the fractured reservoir model (2) at a constant temperature set by the controllable heating platform (1);

[0009] S13: Obtain the first temperature data of the inflowing fluid and the second temperature data of the temperature measuring point at the top of the fractured reservoir model (2);

[0010] S14: Fluid is injected into the first water tank (7) by a peristaltic water pump (6) and liquid calibration is performed using a graduated cylinder;

[0011] S15: Obtain the third temperature data of the temperature measurement point on the lower surface of the fractured reservoir model (2) and the fourth temperature data of the fluid outflow, and set the flow direction of the peristaltic water pump (6);

[0012] S16: Input the parameter data, the first temperature data, the second temperature data, the third temperature data and the fourth temperature data into the forward problem model to obtain the temperature data of the temperature measurement point of the fractured reservoir model (2) under different dominant flow paths;

[0013] S17: Input the temperature data of the temperature measurement point into the inverse problem model to obtain the fracture network distribution data inside the fracture reservoir model (2).

[0014] Preferably, the forward problem model is represented by the following governing equations, and the temperature data of the measuring point is obtained by calculating the temperature field results under different dominant flow paths using the following governing equations:

[0015] (1) The heat transfer-flow coupling control equation of the fractured reservoir model is expressed by the following formula:

[0016] (1);

[0017] (2);

[0018] in, Material density of fractured reservoir model ( ), The isobaric heat capacity of the material in the fractured reservoir model ( ), The thermal conductivity of the material in the fractured reservoir model ( ), Let be the velocity field vector of the fluid. For fluid temperature, For time;

[0019] (2) The flow control equation for the fluid inflow model in fractured reservoirs is expressed by the following formula:

[0020] (3);

[0021] (4);

[0022] (5);

[0023] in, fluid density ( ), For fluid dynamic viscosity ( ), Viscous force per unit area of ​​fluid ( ), For pressure, For volume forces, It is the acceleration due to gravity. This is the Laplace operator.

[0024] Preferably, the inverse problem model is a neural network algorithm.

[0025] Preferably, the fractured reservoir model (2) is a three-layer hemispherical structure, with the outermost layer being a transparent cover, the middle layer being a transparent resin material, and the innermost layer being glass.

[0026] Preferably, the thickness of the intermediate layer is 1 cm.

[0027] Preferably, the fractured reservoir model (2) is prepared by the following steps:

[0028] S21: Select a glass hemispherical structure that satisfies the fractured reservoir model (2);

[0029] S22: The glass hemispherical structure is broken by compression and hammering;

[0030] S23: Clean the broken glass hemisphere structure and bond the external cracks.

[0031] S24: Seal the cracks on the surface of the bonded glass hemispherical structure by means of leak repair;

[0032] S25: Fix the bottom surface of the sealed glass hemispherical structure to the flat plate covered with waterproof cement;

[0033] S26: A transparent heat insulation layer is placed over the outside of the glass hemispherical structure with gaps;

[0034] S27: Inject resin adhesive in stages into the gap between the transparent heat insulation layer and the glass hemispherical structure;

[0035] S28: Determine the location of the fluid inlet and outlet and drill holes.

[0036] Preferably, hydraulic fracturing or triaxial fracturing is used.

[0037] Preferably, during the cracking process, large cracked blocks are spliced ​​together to form cracks with a preset opening as the preferred path.

[0038] Preferably, the preset opening ranges from 1mm to 3mm.

[0039] Compared with existing technologies, the present invention has the following beneficial effects: The fractured reservoir dominant path characterization and inversion experimental system of the present invention includes a micro fractured reservoir containing a fracture network, a temperature acquisition unit, an insulation layer, a controllable heating platform, a peristaltic water pump, and a water tank, solving the problems of existing technologies that can only study the flow heat transfer of single fractures, but cannot invert key parameters such as the morphology, location, and size of the fracture network, and cannot visualize the flow information within the fractured reservoir; the experimental system and the fractured reservoir construction method and data acquisition method provided by the present invention can reconstruct the heat transfer scenario between underground fractured fluids and geothermal reservoirs; the experimental system and implementation path of the present invention provide a complete solution. The feasible experimental operation procedure, through the complete process of "data acquisition required for inverting information inside fractured reservoirs" described above, can be carried out within the experimental system. This allows for continuous exploration of data acquisition and inversion methods under different geothermal and fractured reservoir environments with lower time and economic costs. By continuously improving the inversion technology through a large amount of experimental data, the mature theory can be applied to guide actual geothermal resource exploration. In other words, this invention can simulate the inversion of large-scale geothermal reservoir fracture network distribution information. The data acquisition methods and experience formed after extensive experimental verification can provide an inversion theoretical basis for actual geothermal field investigations. Attached Figure Description

[0040] Exemplary embodiments of the present invention can be more fully understood by referring to the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain the present invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0041] Figure 1This is a schematic diagram of the structure of an experimental system for characterizing and inverting the dominant path of a fractured reservoir according to an exemplary embodiment of this application;

[0042] Figure 2 This is a flowchart of an experimental method for characterizing and inverting the dominant path of a fractured reservoir according to an exemplary embodiment of this application;

[0043] Figure 3 This is a schematic diagram of temperature measurement points for a fractured reservoir model provided according to an exemplary embodiment of this application;

[0044] Figure 4 This is a flowchart illustrating a method for preparing a fractured reservoir model according to an exemplary embodiment of this application.

[0045] Figure Labels

[0046] 1-Controllable heating platform, 2-Fractured reservoir model, 3-First temperature acquisition unit, 4-Second temperature acquisition unit, 5-Third temperature acquisition unit, 6-Peristaltic water pump, 7-First water tank, 8-Second water tank, 9-Insulation layer. Detailed Implementation

[0047] 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 so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0048] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0051] Example 1

[0052] like Figure 1 As shown in the figure, this application provides an experimental system for characterizing and inverting the dominant path of fractured reservoirs, including a controllable heating platform 1, a fractured reservoir model 2, a first temperature acquisition unit 3, a second temperature acquisition unit 4, a third temperature acquisition unit 5, a peristaltic water pump 6, a first water tank 7, a second water tank 8, and a heat insulation layer 9.

[0053] Specifically, the controllable heating platform 1 includes an on / off button, a temperature control button, and a heating time button; the peristaltic water pump 6 includes an on / off button, a flow calibration button, a continuous operation button, and flow increase / decrease buttons.

[0054] Specifically, the controllable heating platform 1 is used to adjust the temperature to simulate the heat source temperature under different geothermal scenarios; the fractured reservoir model 2 is used for the inflow and outflow of fluid; the first temperature acquisition unit 3 is used to acquire the first temperature data of the inflowing fluid; the second temperature acquisition unit 4 is used to acquire the second temperature data of the temperature measuring points on the upper surface of the fractured reservoir model 2; the third temperature acquisition unit 5 is used to acquire the third temperature data of the temperature measuring points on the lower surface of the fractured reservoir model 2 and the fourth temperature data of the outflowing fluid; the peristaltic water pump 6 is used to adjust the flow rate of the fluid flowing into the fractured reservoir model 2; the first water tank 7 is used to supply fluid to the fractured reservoir model 2; the second water tank 8 is used to collect the fluid flowing out of the fractured reservoir model 2; and the insulation layer 9 is used to insulate the fractured reservoir model 2.

[0055] Example 2

[0056] This embodiment discloses an experimental method for characterizing and inverting the dominant path of fractured reservoirs. It is based on the same inventive concept and has the same beneficial effects as the method provided in the foregoing embodiments of this application. The following description is in conjunction with the accompanying drawings.

[0057] like Figure 2 As shown in the embodiments of this application, an experimental method for characterizing and inverting the dominant path of fractured reservoirs is provided, including the following steps:

[0058] S11: Obtain parameter data of the fractured reservoir model, including density, thermal conductivity, specific heat capacity and external geometric parameters of the model in different regions;

[0059] Specifically, using the experimental system for fluid heat transfer visualization research in fractured reservoir model 2, the physical property parameters of glass hemispheres, transparent resin, and cement in transparent reservoirs were detected to obtain key information such as density, thermal conductivity, and specific heat capacity in different regions of the reservoir. Simultaneously, during the fracturing process, the location information of fractures with larger openings within the transparent fractured reservoir was obtained, along with the external geometric information of the entire fractured reservoir.

[0060] S12: Heat the fractured reservoir model at a constant temperature set by the controllable heating platform;

[0061] Specifically, add enough water to the first bucket 7 to meet the experimental requirements, turn on the controllable heating platform 1, set the temperature to the specified temperature, and let it stand for 5-6 hours until the temperature stabilizes.

[0062] S13: Acquire the first temperature data of the inflowing fluid and the second temperature data of the temperature measurement point at the top of the fractured reservoir model;

[0063] Specifically, the bottom of the reservoir model is heated after the controllable heating platform 1 is set to a constant temperature, and the temperature at the top of the hemispherical reservoir is measured to calculate the initial temperature of the model.

[0064] S14: Inject fluid into the first water tank using a peristaltic pump and perform liquid calibration using a graduated cylinder;

[0065] Specifically, to calibrate the flow rate of the peristaltic pump 6, first disconnect the silicone tube connected to the fluid channel inlet of the fractured reservoir model 2, and replace it with a measuring cylinder. After adjusting the flow rate to the set value, click the "Start / Stop" button to collect water. Stop the pump after 30 seconds and check if the actual water volume in the measuring cylinder is equal to the set water volume displayed on the pump. If they are equal, proceed to the next step. If they are not equal, click "Calibrate" to adjust the pump speed to correct its flow rate until the collected water volume is equal to the set water volume. After calibration, reconnect the pump outlet to the rock mass fluid channel inlet. After starting the peristaltic pump 6, record the temperature measurement data at different locations and at equal intervals. After 90 minutes, the differences between the temperature measurement data are relatively obvious and about to stabilize. Since it will take a long time for the data to stabilize, the temperature data at 90 minutes is recorded as the temperature data required for the final inversion.

[0066] S15: Obtain the third temperature data of the temperature measurement point on the lower surface of the fractured reservoir model 2 and the fourth temperature data of the fluid outflow, and set the water pump flow direction;

[0067] Specifically, the initial temperature cloud map of the model was photographed, and the ambient temperature, inlet fluid temperature, heat source temperature, actual temperature, top temperature, and the initial temperature of the eight set temperature measurement points were recorded.

[0068] S16: Input the parameter data, first temperature data, second temperature data, third temperature data and fourth temperature data into the forward problem model to obtain the temperature data of the temperature measurement point under different dominant flow paths of the fractured reservoir model.

[0069] S17: Input the temperature data from the temperature measurement point into the inverse problem model to obtain the fracture network distribution data inside the fractured reservoir model.

[0070] Specifically, the retrieved fracture distribution information was compared with the large-aperture fracture information recorded during the glass fragment assembly process. Furthermore, after starting the peristaltic water pump 6, a fluorescent tracer was placed in the first water tank 7 supplying the injected fluid. During the fluid flow through the fractured reservoir, an ultraviolet lamp was used to irradiate the interior of the transparent fractured reservoir to characterize the fluid flow within the fractured reservoir. An infrared camera was used to characterize the temperature field changes on the fractured reservoir surface to identify the influence of the fracture network distribution on the temperature field. The feasibility of the inversion experimental system was verified through tracer images and temperature field distribution data.

[0071] The forward problem model is represented by the following governing equations. The temperature data at the measurement point is obtained by calculating the temperature field under different dominant flow paths (geometric conditions) using these governing equations:

[0072] (1) The heat transfer-flow coupling control equation of the fractured reservoir model is expressed by the following formula:

[0073] (1);

[0074] (2);

[0075] in, Material density of fractured reservoir model ( ), The isobaric heat capacity of the material in the fractured reservoir model ( ), The thermal conductivity of the material in the fractured reservoir model ( ), Let be the velocity field vector of the fluid. For fluid temperature, For time;

[0076] (2) The flow control equation for the fluid inflow model in fractured reservoirs is expressed by the following formula:

[0077] (3);

[0078] (4);

[0079] (5);

[0080] in, fluid density ( ), For fluid dynamic viscosity ( ), Viscous force per unit area of ​​fluid ( ), For pressure, For volume forces, It is the acceleration due to gravity. This is the Laplace operator.

[0081] The inverse problem model uses a neural network algorithm. Based on the experimental model set, physical properties, and operational parameters, it is imported into the forward problem model. The distribution of different fractures within the microfractured reservoir is simulated in the forward problem, thus deriving the temperature information at measurement points under different fractured reservoir distributions (e.g., ...). Figure 3 Specifically, temperature measurement data under different dominant flow path distributions are used as training data in a neural network algorithm for extensive calculations. Then, real temperature measurement data from actual microfracture reservoirs are fed into the neural network algorithm to obtain structural inversion data of dominant flow path distributions. After comparative analysis, the final result is obtained.

[0082] Example 3

[0083] Reference Figure 2 This embodiment discloses a fractured reservoir model 2 for a fractured reservoir dominant path characterization and inversion experimental system. The fractured reservoir model has a three-layer hemispherical structure, with the outermost layer being a transparent cover, the middle layer being a transparent resin material, and the innermost layer being glass. Specifically, the thickness of the middle layer is 1 cm.

[0084] Specifically, a glass hemisphere was chosen for constructing micro-transparent fractured reservoirs because glass has excellent transparency and light transmission properties, meeting the visibility requirements. Simultaneously, the hemispherical shape facilitates observation of heat transfer within the reservoir. The physical properties of glass and rock are relatively similar, and glass also has good thermal conductivity. Resin adhesive provides excellent insulation and is used as the external coating for transparent fractured reservoir experiments, which is beneficial for high-temperature testing. Furthermore, glass is isotropic, making it a good model for micro-fractured reservoir structures.

[0085] Specifically, the outermost layer is a transparent cover, or more specifically, a transparent acrylic sheet cover, which is the heat insulation layer 9.

[0086] Specifically, the middle layer is made of transparent resin material. Furthermore, in order to achieve the functions of heat preservation, transparency, and sealing, transparent resin glue has become a good choice.

[0087] Example 4

[0088] This embodiment discloses a method for preparing a fractured reservoir model, which is based on the same inventive concept and has the same beneficial effects as the method provided in the foregoing embodiments of this application. The following description is in conjunction with the accompanying drawings.

[0089] Reference Figure 4 This embodiment discloses a method for preparing a fractured reservoir model, including the following steps:

[0090] S21: Select a glass hemispherical structure that satisfies the fractured reservoir model;

[0091] Specifically, a glass hemispherical structure that meets the model requirements is selected;

[0092] S22: The glass hemispherical structure is broken by compression and hammering;

[0093] Specifically, to construct a visualized fractured reservoir with a random fracture network, fracturing is first performed using methods such as hydraulic fracturing or triaxial fracturing. Simultaneously, methods such as hammering and cutting can be used to break the glass spheres. During hydraulic or triaxial fracturing, a transparent woven mesh is used to cover the glass hemispheres to prevent them from breaking into multiple fragments that are difficult to reassemble. Further breaking the glass spheres using hammering and cutting methods can control the distribution of flow regions within the transparent fractured reservoir, thereby verifying the function of fracture region inversion. Specifically, the process includes the following:

[0094] First, cut any point on the glass ball to construct a cross-shaped striking point;

[0095] Use an awl, hammer, or similar tool to strike the point. To prevent the glass ball from scattering during the hammering process, wrap it in a mesh bag.

[0096] For large structures that are difficult to hammer, pre-fracking and cutting methods can be used for structural cutting.

[0097] The glass was then repeatedly struck with a glass ball to break it into several glass blocks of different sizes.

[0098] S23: Clean the broken glass hemisphere structure and bond the external cracks.

[0099] Specifically, the glass blocks of varying sizes obtained in step S22 are first cleaned, then wiped with a lint-free cloth and dried to ensure their transparency. Simultaneously, to reduce the difficulty of assembly, a method of simultaneous hammering and assembly is employed during the hammering process. For the clean, dried glass blocks, the broken pieces inside the glass spheres are only assembled to maintain fluidity. During the assembly process, large cracked pieces from the hammering process are joined to create cracks with a larger opening as the advantageous path. Compared to the opening of other cracks (0.1-1mm), the opening of the advantageous path reserved during the assembly process is between 1-3mm.

[0100] After constructing the dominant path, a transparent thin string is placed within it to compare the impact of the presence and degree of the dominant path on the short-circuit effect and temperature field of the fractured reservoir. Glass blocks on the surface of the glass sphere are then bonded together.

[0101] Finally, to ensure clarity, UV-curing adhesive was used to bond the external cracks of the glass hemisphere. During the bonding process, to prevent adhesive from entering the crack network inside the glass hemisphere, a faster-curing UV-curing adhesive was used, and the bonding was carried out under high-intensity UV light.

[0102] S24: Seal the cracks on the surface of the bonded glass hemispherical structure by means of leak repair;

[0103] Specifically, for the transparent fractured reservoir model bonded in step S3, the fractures on the hemispherical surface need to be sealed using a leak-sealing method. This is mainly done through two methods: spot sealing and full sealing. First, check the leakage of the glass plate sphere bonded in step S23. Invert the sealed glass hemisphere and pour clean water into it from the bottom, observing the leakage from the bottom. For any leaks on the glass hemisphere, apply spot sealing adhesive until no leakage is observed on the surface. To further ensure the sealing of the glass hemisphere surface, apply resin adhesive to the surface, forming a protective film that achieves both sealing and transparency. This lays the foundation for subsequent resin adhesive sealing.

[0104] S25: Fix the bottom surface of the sealed glass hemispherical structure to the flat plate covered with waterproof cement;

[0105] Specifically, for the transparent fractured reservoir model bonded in step S24, in order to heat this transparent fractured reservoir while ensuring the smoothness of the heating surface and preventing water leakage from the fractured reservoir, a layer of waterproof cement is evenly spread on a flat and smooth slab. After the bottom cement is leveled, the bottom surface of the transparent fractured reservoir model (hemispherical) constructed in step S24 is immediately placed on the cement. At the same time, a transparent cover with a diameter larger than the hemispherical fractured reservoir is placed over it, and a weight is used to press the transparent acrylic cover tightly against the cement, ensuring that the bottom cement is in full contact and bonded to the transparent cover and the transparent fractured reservoir. A weight is then placed on top of the transparent acrylic cover for continuous pressure.

[0106] S26: A transparent heat insulation layer is placed over the outside of the glass hemispherical structure with gaps;

[0107] Specifically, for the completed transparent fractured reservoir model in step S25, there is a gap between the transparent acrylic sheet cover and the hemispherical transparent fractured reservoir, and the bottom cement acts as a seal. To achieve the functions of heat preservation, transparency, and sealing, transparent resin adhesive can be used as the material. In this embodiment, the transparent fractured reservoir model uses transparent resin material as the material to fill the gap (about 1 cm) between the fractured reservoir and the transparent acrylic sheet cover.

[0108] S27: Inject resin adhesive in stages into the gap between the transparent heat insulation layer and the glass hemispherical structure;

[0109] Specifically, a small hole is drilled in the top of the transparent acrylic cover, and the prepared resin glue is injected into this gap. To maximize the transparency of the resin, it is injected in layers, each approximately 2.5 centimeters thick. Each layer takes about 36 hours to set, and after multiple injections, the entire transparent fractured reservoir is constructed. At this point, a transparent fractured reservoir model with cement at the bottom as a heating surface and transparent resin surrounding it as insulation has been completed.

[0110] S28: Determine the location of the fluid inlet and outlet and drill holes.

[0111] Specifically, a thin hook is used to reach deep into the inlet and outlet holes to retrieve a transparent thread placed pre-placed in the fractured reservoir. In locations difficult to reach from the inlet, a hole can be drilled using an electric drill, and the hook inserted to retrieve the thread. The experimental procedure is repeated, and the measurement data is recorded. Infrared spectral images showing the presence or absence of the thread, as well as tracer images, are captured and compared. This allows for the assessment of the influence of the dominant flow path on the reservoir's physical field. Furthermore, the measurement data regarding the presence or absence of the dominant flow path is imported into an inversion platform to retrieve the location information of the dominant flow path.

[0112] It should be noted that the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0113] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0114] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application.

Claims

1. An experimental method for a fractured reservoir dominant path characterization and inversion experimental system, characterized in that, The fractured reservoir dominant path characterization and inversion experimental system includes a controllable heating platform (1), a fractured reservoir model (2), a first temperature acquisition unit (3), a second temperature acquisition unit (4), a third temperature acquisition unit (5), a peristaltic water pump (6), a first water tank (7), a second water tank (8), and a heat insulation layer (9); the experimental method includes the following steps: S11: Obtain parameter data of fractured reservoir model (2), the parameter data including density, thermal conductivity, specific heat capacity and external geometric parameters of different regions; S12: Heat the fractured reservoir model (2) at a constant temperature set by the controllable heating platform (1); S13: Obtain the first temperature data of the inflowing fluid and the second temperature data of the temperature measuring point at the top of the fractured reservoir model (2); S14: Fluid is injected into the first water tank (7) by a peristaltic water pump (6) and liquid calibration is performed using a graduated cylinder; S15: Obtain the third temperature data of the temperature measurement point on the lower surface of the fractured reservoir model (2) and the fourth temperature data of the fluid outflow, and set the flow direction of the peristaltic water pump (6); S16: Input the parameter data, the first temperature data, the second temperature data, the third temperature data and the fourth temperature data into the forward problem model to obtain the temperature data of the temperature measurement point of the fractured reservoir model (2) under different dominant flow paths; S17: Input the temperature data of the temperature measurement point into the inverse problem model to obtain the fracture network distribution data inside the fracture reservoir model (2).

2. The experimental method according to claim 1, characterized in that, The forward problem model is represented by the following governing equations, and the temperature data of the temperature measurement point is obtained by calculating the temperature field results under different dominant flow paths using the following governing equations: (1) The heat transfer-flow coupling control equation of the fractured reservoir model is expressed by the following formula: （1）； （2）； in, Material density of fractured reservoir model ( ), The isobaric heat capacity of the material in the fractured reservoir model ( ), The thermal conductivity of the material in the fractured reservoir model ( ), Let be the velocity field vector of the fluid. For fluid temperature, For time; (2) The flow control equation for the fluid inflow model in fractured reservoirs is expressed by the following formula: （3）； （4）； （5）； in, fluid density ( ), For fluid dynamic viscosity ( ), Viscous force per unit area of ​​fluid ( ), For pressure, For volume forces, It is the acceleration due to gravity. This is the Laplace operator.

3. The experimental method according to claim 2, characterized in that, The inverse problem model is a neural network algorithm.

4. The experimental method according to claim 3, characterized in that, The fractured reservoir model (2) is a three-layer hemispherical structure, with the outermost layer being a transparent cover, the middle layer being a transparent resin material, and the innermost layer being glass.

5. The experimental method according to claim 4, characterized in that, The thickness of the intermediate layer is 1 cm.

6. The experimental method according to claim 5, characterized in that, The fractured reservoir model (2) was prepared through the following steps: S21: Select a glass hemispherical structure that satisfies the fractured reservoir model (2); S22: The glass hemispherical structure is broken by compression and hammering; S23: Clean the broken glass hemisphere structure and bond the external cracks. S24: Seal the cracks on the surface of the bonded glass hemispherical structure by means of leak repair; S25: Fix the bottom surface of the sealed glass hemispherical structure to the flat plate covered with waterproof cement; S26: A transparent heat insulation layer is placed over the outside of the glass hemispherical structure with gaps; S27: Inject resin adhesive in stages into the gap between the transparent heat insulation layer and the glass hemispherical structure; S28: Determine the location of the fluid inlet and outlet and drill holes.

7. The experimental method according to claim 6, characterized in that, Fracturing can be performed using hydraulic fracturing or triaxial fracturing.

8. The experimental method according to claim 7, characterized in that, During the cracking process, large cracked blocks will be pieced together to form cracks with a preset opening size, which will serve as the preferred path.

9. The experimental method according to claim 8, characterized in that, The preset opening range is 1mm-3mm.

Images