Fractured reservoir dominant path representation inversion experiment system and method, fractured reservoir model and preparation method

Abstract

The invention discloses a fractured reservoir dominant path characterization inversion experiment system and method, a fractured reservoir model and a preparation method. According to the experiment system, a fractured reservoir construction method and a data acquisition method provided by the invention, an underground fractured fluid and geothermal reservoir heat exchange scene can be restored; according to the experimental system and the implementation path, a feasible experimental operation process is provided, and a complete process of acquiring data required by inversion of internal information of the fractured reservoir is carried out in the experimental system; data acquisition methods and inversion methods under different geothermal environments and fractured reservoir environments can be continuously explored with low time and economic cost, and the inversion technology is continuously improved through a large amount of experimental data, so that mature theories are used for guidance of actual geothermal resource exploration sites. Inversion of large-scale geothermal reservoir fracture network distribution information can be simulated, and an inversion theoretical basis can be provided for investigation of an actual geothermal field site.

Description

Technical Field

[0001] The present invention belongs to the field of information inversion in fractured reservoirs, and in particular relates to a fractured reservoir dominant path characterization inversion experimental system and method, a fractured reservoir model and a preparation method. Background Art

[0002] my country is rich in deep geothermal resources. Compared with wind and solar energy, it has outstanding advantages such as stability and no geographical restrictions, which is of great strategic significance for achieving the "dual carbon" goal. Before carrying out geothermal resource development projects, it is often necessary to determine geothermal resource information, geothermal reservoir parameters, etc. to ensure the quality and reserves of geothermal resources in the target geothermal area. According to statistics from relevant literature, the proportion of geothermal development projects suspended or terminated due to heat reservoir quality problems reached about 35%, accounting for the first of all reasons. Therefore, in order to ensure the rational development and efficient utilization of geothermal resources, the key parameters of geothermal reservoirs must be evaluated first. Limited by the geothermal reservoir environment, the internal structure of the reservoir is often complex, in a high temperature and high pressure state, and the inversion of fracture channels is relatively difficult. The current mainstream microseismic survey technology can only be used as a basis for judging the internal flow of the reservoir, and it is impossible to quantify the morphology, position, and size of the internal fractures of the reservoir. Therefore, the method of effectively inverting geothermal reservoir parameters needs further exploration.

[0003] To achieve accurate inversion of geothermal reservoir parameters, it is first necessary to collect data on the geothermal state information or geological structure information in the area around the reservoir, and use this as the basis for inverting unknown fracture reservoir parameters. For the required monitoring data, it is necessary to further evaluate the quality of geothermal resources by exploring the relationship between it and reservoir parameters. Therefore, how to ensure the availability and effectiveness of the data is a task that requires repeated verification. By conducting high-temperature rock inversion experiments, the experimental plan can be further optimized on the basis of the previous experimental platform to explore more complex and variable geothermal reservoir parameter inversion methods, and ultimately provide certain technical reference value for actual geothermal exploration work.

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

[0005] Based on this, it is necessary to provide a fracture reservoir dominant path characterization inversion experimental system and method, a fracture reservoir model and preparation method to address the existing problems.

[0006] In a first aspect, the present application discloses a fracture reservoir dominant path characterization inversion experimental system, comprising: A controllable heating platform (1) for adjusting the temperature to simulate the heat source temperature under different geothermal scenarios; Fracture reservoir model (2), for fluid inflow and outflow; A first temperature collection unit (3), used for collecting first temperature data of the inflowing fluid; A second temperature acquisition unit (4) is used to acquire second temperature data of a temperature measurement point on the upper surface of the fracture reservoir model (2); A third temperature acquisition unit (5) is used to acquire third temperature data of a temperature measurement point on the lower surface of the fracture reservoir model (2) and fourth temperature data of fluid outflow; A peristaltic water pump (6) for adjusting the flow rate of the fluid flowing into the fracture reservoir model (2); A first water bucket (7) is used to provide fluid to the fracture reservoir model (2); A second water bucket (8) for collecting fluid flowing out of the fracture reservoir model (2); The thermal insulation layer (9) is used to thermally insulate the fracture reservoir model (2).

[0007] Preferably, the method comprises the following steps: S11: Acquire parameter data of the fracture reservoir model, wherein the parameter data includes density, thermal conductivity, specific heat capacity of different regions and external geometric parameters of the model; S12: heating the fracture reservoir model according to a constant temperature set by the controllable heating platform; S13: Acquire first temperature data of the inflow fluid and second temperature data of the top temperature measuring point of the fracture reservoir model; S14: injecting fluid into the first water bucket through a peristaltic water pump and performing liquid calibration using a measuring cylinder; S15: obtaining third temperature data of the lower surface temperature measuring point in the fracture reservoir model and fourth temperature data of fluid outflow, and setting the flow direction of the water pump; S16: inputting 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 measuring points of the fracture reservoir model under different dominant flow paths; S17: Inputting the temperature data of the temperature measuring points into the inverse problem model to obtain the fracture network distribution data inside the fracture reservoir model.

[0008] Preferably, the method according to claim 2 is characterized in that the forward problem model is represented by the following control equation, and the temperature data of the temperature measuring point is obtained by calculating the temperature field results under different dominant flow paths through the following control equation: (1) The heat transfer-flow coupling control equation of the reservoir fracture model is expressed by the following formula: ; ; in, is the material density of the fracture reservoir model ( ), is the constant pressure heat capacity of the material in the fracture reservoir model ( ), is the thermal conductivity of the fracture reservoir model ( ), is the velocity field vector of the fluid, is the fluid temperature, For time; (2) The flow control equation of fluid flowing into the reservoir fracture is expressed by the following formula: ; ; ; in, is the fluid density ( ), is the fluid dynamic viscosity ( ), is the viscous force per unit area of ​​the fluid ( ), For pressure, is the volume force, is the acceleration due to gravity, is the Laplace operator.

[0009] Preferably, the inverse problem model is a neural network algorithm.

[0010] In the second aspect, an embodiment of the present application discloses a fracture reservoir model of the fracture reservoir dominant path characterization inversion experimental system as described in the first aspect, wherein the fracture reservoir model is a three-layer hemispherical structure, the outermost layer is a transparent cover, the middle layer is a transparent resin material, and the innermost layer is glass.

[0011] Preferably, the thickness of the intermediate layer is 1 cm.

[0012] In a third aspect, the present application discloses a method for preparing a fracture reservoir model as described in the third aspect, comprising the following steps: S21: selecting a glass hemisphere structure that satisfies the fracture reservoir model; S22: breaking the glass hemispherical structure by fracturing and cracking; S23: cleaning the broken glass hemisphere structure and gluing the external cracks; S24: sealing the cracks on the surface of the bonded glass hemisphere structure by 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-insulating layer is placed on the outer side of the glass hemisphere structure with a gap; S27: injecting resin glue into the gap between the transparent insulation layer and the glass hemisphere structure in batches; S28: Determine the positions of the fluid inlet and the fluid outlet and drill holes.

[0013] Preferably, the fracturing adopts hydraulic fracturing or triaxial fracturing.

[0014] Preferably, during the cracking process, large crack blocks are spliced ​​into cracks with a preset opening as a dominant path.

[0015] Preferably, the preset opening ranges from 1 mm to 3 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the fracture reservoir advantage path characterization inversion experimental system of the present invention includes a micro fracture reservoir containing a fracture network, a temperature acquisition unit, an insulation layer, a controllable heating platform, a peristaltic water pump, and a water bucket, which solves the problem that the prior art can only study the flow and heat exchange of a single fracture, but cannot invert the key parameters such as the fracture network morphology, position, and size, and cannot visualize the flow information in the fracture reservoir; the experimental system of the present invention and the fracture reservoir construction method and data acquisition method provided can restore the heat exchange scene between underground fracture fluid and geothermal reservoir; the experimental system and implementation path of the present invention provide a cutting A feasible experimental operation process, by carrying out the complete process of "realizing the data collection required for inversion of internal information of fractured reservoirs" as mentioned above in the experimental system, can continuously explore data collection methods and inversion methods in different geothermal environments and fractured reservoir environments at a lower time and economic cost, and continuously improve the inversion technology through a large amount of experimental data, so that mature theories can be used for guidance in actual geothermal resource exploration sites, that is, the present invention can simulate the inversion of large-scale geothermal reservoir fracture network distribution information, and the data collection methods and experience formed after a large number of experimental verifications can provide an inversion theoretical basis for actual geothermal field site investigations. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By referring to the following drawings, the exemplary embodiments of the present invention can be more completely understood. The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present invention and do not constitute a limitation of the present invention. In the drawings, the same reference numerals generally represent the same parts or steps.

[0018] Figure 1 A structural schematic diagram of a fracture reservoir dominant path characterization inversion experimental system provided according to an exemplary embodiment of the present application; Figure 2A flowchart of an inversion experimental method for characterizing a dominant path of a fracture reservoir provided according to an exemplary embodiment of the present application; Figure 3 A schematic diagram of temperature measurement points of a fracture reservoir model provided according to an exemplary embodiment of the present application; Figure 4 The present invention is a flowchart of a method for preparing a fracture reservoir model according to an exemplary embodiment of the present application.

[0019] Reference numerals 1-controllable heating platform, 2-fracture reservoir model, 3-first temperature acquisition unit, 4-second temperature acquisition unit, 5-third temperature acquisition unit, 6-peristaltic water pump, 7-first water bucket, 8-second water bucket, 9-thermal insulation layer. DETAILED DESCRIPTION

[0020] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention 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 understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] 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.

[0024] Example 1 like Figure 1As shown, an embodiment of the present application provides a fracture reservoir dominant path characterization inversion experimental system, including a controllable heating platform 1, a fracture 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 bucket 7, a second water bucket 8 and an insulation layer 9.

[0025] Specifically, the controllable heating platform 1 includes an on / off button, a temperature control button, a heating time button, etc.; the peristaltic water pump 6 includes an on / off button, a flow calibration button, a continuous operation button, and flow increase / decrease buttons.

[0026] Specifically, the controllable heating platform 1 is used to adjust the temperature to simulate the heat source temperature under different geothermal scenarios; the fracture reservoir model 2 is used for the inflow and outflow of fluid; the first temperature acquisition unit 3 is used to collect the first temperature data of the inflowing fluid; the second temperature acquisition unit 4 is used to collect the second temperature data of the temperature measuring point on the upper surface of the fracture reservoir model 2; the third temperature acquisition unit 5 is used to collect the third temperature data of the temperature measuring point on the lower surface of the fracture reservoir model 2 and the fourth temperature data of the fluid outflow; the peristaltic water pump 6 is used to adjust the flow rate of the fluid flowing into the fracture reservoir model 2; the first water bucket 7 is used to provide fluid to the fracture reservoir model 2; the second water bucket 8 is used to collect the fluid flowing out of the fracture reservoir model 2; the insulation layer 9 is used to insulate the fracture reservoir model 2.

[0027] Example 2 This embodiment discloses a fracture reservoir dominant path characterization inversion experimental method, which is based on the same inventive concept as the method provided in the previous embodiment of the present application and has the same beneficial effects.

[0028] like Figure 2 As shown, the embodiment of the present application provides a fracture reservoir dominant path characterization inversion experimental method, comprising the following steps: S11: Acquire parameter data of the fracture reservoir model, wherein the parameter data includes density, thermal conductivity, specific heat capacity of different regions and external geometric parameters of the model; Specifically, the experimental system of fluid heat exchange visualization research of fracture reservoir model 2 is used to detect the physical property parameters of glass hemispheres, transparent resins and cement in the transparent reservoir to obtain key information such as density, thermal conductivity, specific heat capacity, etc. in different regions of the reservoir. At the same time, the location information of the fractures with larger openings in the transparent fracture reservoir is obtained during the fracturing process, and the external geometric information of the entire fracture reservoir is obtained.

[0029] S12: heating the fracture reservoir model according to a constant temperature set by the controllable heating platform; Specifically, add enough water to the first water bucket 7 to meet the experimental requirements, turn on the controllable heating table 1, adjust the set temperature to the specified temperature, and heat for 5-6 hours until the temperature stabilizes.

[0030] S13: Acquire first temperature data of the inflow fluid and second temperature data of the temperature measuring point at the top of the fracture reservoir model; Specifically, the bottom of the reservoir model is heated by setting a constant temperature through the controllable heating platform 1, and the temperature of the top of the hemispherical reservoir is measured to calculate the initial temperature of the model.

[0031] S14: injecting fluid into the first water bucket through a peristaltic water pump and performing liquid calibration using a measuring cylinder; Specifically, the flow rate of the peristaltic water pump 6 is calibrated. First, the silicone tube connected to the fluid channel entrance of the fracture reservoir model 2 is disconnected, and replaced with a measuring cylinder. After adjusting the flow rate to the set value, click the "Start and Stop" button to receive water, stop when the duration is 30s, and check whether the actual water volume in the measuring cylinder is equal to the set water volume displayed on the water pump. If they are equal, the next step can be carried out. If they are not equal, click "Calibrate" to adjust the speed of the water pump to correct its flow rate until the water volume is equal to the set water volume; after the calibration is completed, the water pump outlet is connected to the entrance of the rock fluid channel. After starting the peristaltic water pump 6, record the temperature measurement point data at different positions, and record the data of the temperature measurement points at equal intervals. At 90 minutes, the gap between the data of each temperature measurement point is relatively obvious and is about to reach stability. If it takes a long time to stabilize, the temperature data at 90 minutes is recorded as the temperature data required for the final inversion.

[0032] S15: obtaining the third temperature data of the temperature measuring point on the lower surface of the fracture reservoir model 2 and the fourth temperature data of the fluid outflow, and setting the flow direction of the water pump; Specifically, the initial temperature cloud map of the model is photographed, and the ambient temperature, inlet fluid temperature, heat source temperature, actual temperature and top temperature as well as the initial temperatures of the eight set temperature measurement points are recorded.

[0033] S16: inputting 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 measuring points of the fracture reservoir model under different dominant flow paths; S17: Input the temperature data of the temperature measuring points into the inverse problem model to obtain the fracture network distribution data inside the fracture reservoir model.

[0034] Specifically, the inverted fracture distribution information is compared with the large-opening fracture information recorded during the splicing process of glass fragments. In addition, after the peristaltic water pump 6 is started, a fluorescent tracer is placed in the first water bucket 7 that provides the injection fluid. During the flow of the fluid in the fracture reservoir, an ultraviolet lamp is used to illuminate the inside of the transparent fracture reservoir to characterize the flow of the fluid in the fracture reservoir. An infrared camera is used to characterize the temperature field changes on the surface of the fracture reservoir and to identify the influence of the fracture network distribution on the temperature field. The principle feasibility of the inversion experimental system is verified by the tracer image and the temperature field distribution.

[0035] The direct problem model is represented by the following control equation, and the temperature data of the temperature measuring point is obtained by calculating the temperature field results under different advantageous flow paths (geometric conditions) through the following control equation: (1) The heat transfer-flow coupling control equation of the reservoir fracture model is expressed by the following formula: ; ; in, is the material density of the fracture reservoir model ( ), is the constant pressure heat capacity of the material in the fracture reservoir model ( ), is the thermal conductivity of the fracture reservoir model ( ), is the velocity field vector of the fluid, is the fluid temperature, For time; (2) The flow control equation of fluid flowing into the reservoir fracture is expressed by the following formula: ; ; ; in, is the fluid density ( ), is the fluid dynamic viscosity ( ), is the viscous force per unit area of ​​the fluid ( ), For pressure, is the volume force, is the acceleration due to gravity, is the Laplace operator.

[0036] Among them, the inverse problem model is a neural network algorithm. According to the set of experimental models, physical properties, operation and other parameters, the forward problem model is imported, and the distribution of different fractures in the micro-fracture reservoir is simulated in the forward problem. This will derive the temperature information of the measuring points under different fracture reservoir distributions (such as Figure 3 Specifically, the temperature measurement point data under different dominant flow path distributions are placed in the neural network algorithm as training data, and a large number of calculations are performed. Then, the real temperature data of the measuring points in the actual micro-fracture reservoir are placed in the neural network algorithm to obtain the structural inversion data of the dominant flow path distribution. After comparative analysis, the final result is obtained.

[0037] Example 3 Reference Figure 2 This embodiment discloses a fracture reservoir model 2 of a fracture reservoir dominant path characterization inversion experimental system. The fracture reservoir model is a three-layer hemispherical structure, the outermost layer is a transparent cover, the middle layer is a transparent resin material, and the innermost layer is glass. Specifically, the thickness of the middle layer is 1 cm.

[0038] Specifically, a glass hemisphere is selected to construct a micro transparent fracture reservoir, because glass has good perspective and light transmission properties, which meets the visual requirements. At the same time, the hemisphere shape makes it easier to observe the flow and heat exchange in the reservoir. The physical properties of glass and rock are relatively similar, and they have good thermal conductivity. Resin glue has a good thermal insulation effect. Resin glue is used for the external wrapping of transparent fracture reservoir experiments, which is conducive to high temperature tests; at the same time, glass is isotropic and is a better micro fracture reservoir construction model.

[0039] Specifically, the outermost layer is a transparent cover, and further, it can be a transparent acrylic plate cover, that is, the heat insulation layer 9.

[0040] Specifically, the middle layer is a transparent resin material. Furthermore, in order to achieve the effects of heat preservation, transparency and sealing, transparent resin glue becomes a good choice.

[0041] Example 4 This embodiment discloses a method for preparing a fracture reservoir model, which is based on the same inventive concept as the method provided in the previous embodiment of the present application and has the same beneficial effects.

[0042] Reference Figure 4 This embodiment discloses a method for preparing a fracture reservoir model, comprising the following steps: S21: Select the glass hemisphere structure that meets the fracture reservoir model; Specifically, a glass hemispherical structure that meets the model requirements is selected; S22: breaking the glass hemispherical structure by fracturing and cracking; Specifically, in order to construct a visualized fracture reservoir of a random fracture network, firstly, hydraulic fracturing or triaxial fracturing is used for fracturing, and the glass ball can also be broken by methods such as cracking and cutting. During the hydraulic fracturing or triaxial fracturing process, a transparent woven mesh is used to cover the glass hemisphere to prevent the glass ball from breaking into multiple pieces during the fracturing process and being difficult to restore. Breaking the glass ball by cracking, cutting and other methods can control the flow area distribution in the transparent fracture reservoir, thereby achieving the function of verifying the fracture area inversion. Specifically, it includes the following processes: First, cut any point of the glass ball to construct a cross-shaped striking point; Use an awl, hammer, etc. to hammer the point. To prevent the glass ball from splashing during the hammering process, use a mesh woven bag to wrap the glass ball; For large structures that are difficult to hammer, pre-fracturing and cutting methods can be used for structural cutting; The glass plate is then hammered several times to form multiple glass blocks of different sizes.

[0043] S23: cleaning the broken glass hemisphere structure and gluing the external cracks; Specifically, for the glass blocks of different sizes obtained in the above step S22, they are first cleaned, then wiped with a dust-free cloth and dried to ensure their transparency. At the same time, in order to reduce the difficulty in splicing, a method of splicing while tapping is used during the tapping process. For the clean glass blocks after cleaning and drying, the broken blocks inside the glass ball are only spliced ​​to ensure fluidity. In the process of splicing, the large crack blocks in the tapping process are spliced ​​into cracks with a larger opening as the dominant path. Compared with the opening of other cracks (0.1-1mm), the opening of the dominant path reserved in the splicing process is between 1-3mm.

[0044] After the dominant path is constructed, a transparent string is placed in the dominant path to compare the effect of the dominant path on the short-circuit effect and temperature field of the fracture reservoir and the degree of the dominant path. The glass blocks on the surface of the glass ball are bonded.

[0045] Finally, in order to ensure the clarity, shadowless glue was used to bond the external cracks of the glass hemisphere. During the bonding process, in order to prevent the glue from entering the crack network inside the glass hemisphere, shadowless glue with a faster solidification speed was used and bonded under high-intensity ultraviolet light.

[0046] S24: sealing the cracks on the surface of the bonded glass hemisphere structure by leak repair; Specifically, for the bonded transparent fracture reservoir model in step S3, the cracks on the surface of the hemisphere must be sealed by a leak patching method. There are mainly two ways to patch leaks (spot patching and full patching). First, check the water leakage of the glass plate ball bonded in step S23, place the blocked glass hemisphere upside down, introduce clean water from the bottom of the glass hemisphere, and observe the water leakage on the surface of the glass ball from the bottom. For the leaking points of the glass hemisphere, spot patching with shadowless glue is performed until the surface of the glass hemisphere is checked for no leakage. In order to ensure the sealing of the surface of the glass hemisphere again, resin glue is used to pour the glass surface to form a protective film on the surface of the glass hemisphere, which achieves both the sealing effect and the transparent visualization effect. It lays the foundation for the subsequent resin glue sealing.

[0047] S25: Fix the bottom surface of the sealed glass hemispherical structure to the flat plate covered with waterproof cement; Specifically, for the transparent fracture reservoir model bonded in step S24, in order to heat the transparent fracture reservoir, it is necessary to ensure the smoothness of the heating surface and prevent water leakage of the fracture reservoir. A layer of waterproof cement is evenly spread on a flat and smooth board. After the bottom cement is flattened, the bottom surface of the transparent fracture 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 fracture reservoir is used to cover the hemispherical transparent fracture reservoir, and a heavy object is used to press the transparent acrylic cover and the cement tightly, so that the cement at the bottom is fully in contact with and adhered to the transparent cover and the transparent fracture reservoir. A heavy object is pressed on the transparent acrylic cover to continuously press it.

[0048] S26: A transparent heat-insulating layer is placed on the outer side of the glass hemisphere structure with a gap; Specifically, for the completed transparent fracture reservoir model in step S25, there is a gap between the transparent acrylic plate cover and the hemispherical transparent fracture reservoir, and the bottom cement plays a sealing role. In order to achieve the effects of heat preservation, transparency, and sealing, transparent resin glue can be used as a material. The transparent fracture reservoir model of this embodiment uses a transparent resin material as a material to fill the gap (about 1 cm) between the fracture reservoir and the transparent acrylic cover.

[0049] S27: injecting resin glue into the gap between the transparent insulation layer and the glass hemisphere structure in batches; Specifically, a small hole is drilled on the top of the transparent acrylic cover, and the blended resin glue is injected into the gap. In order to maximize the transparency of the transparent resin, the transparent resin is injected in layers. Each layer is about 2.5 cm. The solidification time of each layer is about 36 hours. After multiple injections, the entire transparent fracture reservoir is constructed. At this point, a transparent fracture reservoir model with cement as a heating plane at the bottom and transparent resin as an insulation material around it has been constructed.

[0050] S28: Determine the positions of the fluid inlet and the fluid outlet and drill holes.

[0051] Specifically, a thin hook is used to penetrate the inlet and outlet holes and hook out the transparent thin wire placed in the fracture reservoir in advance. In some places where the entrance is difficult to reach, a hole can be drilled by an electric drill, and the hook is inserted to hook out the transparent thin wire. Repeat the above experimental process and record the data of the measuring points. At the same time, the infrared characterization cloud map and the tracer cloud map of the presence or absence of the thin wire are taken and compared respectively. In this way, the influence of the existence of the dominant path on the reservoir physical field can be judged from the physical field of the fracture reservoir. In addition, the measuring point data of the presence or absence of the dominant path are imported into the inversion platform to invert the location information of the dominant flow path.

[0052] It should be noted that the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains 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 box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0053] Those skilled in the art can 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.

[0054] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0055] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application.

Claims

1. A fracture reservoir dominant path characterization inversion experimental system, characterized in that: include: A controllable heating platform (1) for adjusting the temperature to simulate the heat source temperature under different geothermal scenarios; Fracture reservoir model (2), for fluid inflow and outflow; A first temperature collection unit (3), used for collecting first temperature data of the inflowing fluid; A second temperature acquisition unit (4) is used to acquire second temperature data of a temperature measurement point on the upper surface of the fracture reservoir model (2); A third temperature acquisition unit (5) is used to acquire third temperature data of a temperature measurement point on the lower surface of the fracture reservoir model (2) and fourth temperature data of fluid outflow; A peristaltic water pump (6) for adjusting the flow rate of the fluid flowing into the fracture reservoir model (2); A first water bucket (7) is used to provide fluid to the fracture reservoir model (2); A second water bucket (8) for collecting fluid flowing out of the fracture reservoir model (2); The thermal insulation layer (9) is used to thermally insulate the fracture reservoir model (2).

2. An experimental method for the fracture reservoir dominant path characterization inversion experimental system according to claim 1, characterized in that: The steps include: S11: Acquire parameter data of the fracture reservoir model, wherein the parameter data includes density, thermal conductivity, specific heat capacity of different regions and external geometric parameters of the model; S12: heating the fracture reservoir model according to a constant temperature set by the controllable heating platform; S13: Acquire first temperature data of the inflow fluid and second temperature data of the top temperature measuring point of the fracture reservoir model; S14: injecting fluid into the first water bucket through a peristaltic water pump and performing liquid calibration using a measuring cylinder; S15: obtaining third temperature data of the lower surface temperature measuring point in the fracture reservoir model and fourth temperature data of fluid outflow, and setting the flow direction of the water pump; S16: inputting 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 measuring points of the fracture reservoir model under different dominant flow paths; S17: Inputting the temperature data of the temperature measuring points into the inverse problem model to obtain the fracture network distribution data inside the fracture reservoir model.

3. The method according to claim 2, characterized in that The direct problem model is represented by the following control equation, and the temperature data of the temperature measuring point is obtained by calculating the temperature field results under different dominant flow paths through the following control equation: (1) The heat transfer-flow coupling control equation of the reservoir fracture model is expressed by the following formula: ； ； in, is the material density of the fracture reservoir model ( ), is the constant pressure heat capacity of the material in the fracture reservoir model ( ), is the thermal conductivity of the fracture reservoir model ( ), is the velocity field vector of the fluid, is the fluid temperature, For time; (2) The flow control equation of fluid flowing into the reservoir fracture is expressed by the following formula: ； ； ； in, is the fluid density ( ), is the fluid dynamic viscosity ( ), is the viscous force per unit area of ​​the fluid ( ), For pressure, is the volume force, is the acceleration due to gravity, is the Laplace operator.

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

5. A fracture reservoir model of the fracture reservoir dominant path characterization inversion experimental system according to claim 1, characterized in that: The fracture reservoir model (2) is a three-layer hemispherical structure, the outermost layer is a transparent cover, the middle layer is a transparent resin material, and the innermost layer is glass.

6. The fracture reservoir model according to claim 5, characterized in that: The thickness of the middle layer is 1 cm.

7. A method for preparing a fracture reservoir model according to any one of claims 5 to 6, characterized in that: The steps include: S21: selecting a glass hemisphere structure that satisfies the fracture reservoir model; S22: breaking the glass hemispherical structure by fracturing and cracking; S23: cleaning the broken glass hemisphere structure and gluing the external cracks; S24: sealing the cracks on the surface of the bonded glass hemisphere structure by 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-insulating layer is placed on the outer side of the glass hemisphere structure with a gap; S27: injecting resin glue into the gap between the transparent insulation layer and the glass hemisphere structure in batches; S28: Determine the positions of the fluid inlet and the fluid outlet and drill holes.

8. The preparation method according to claim 7, characterized in that: Fracturing is done by hydraulic fracturing or triaxial fracturing.

9. The preparation method according to claim 8, characterized in that: During the cracking process, large crack blocks are spliced ​​into cracks with preset openings as the dominant path.

10. The preparation method according to claim 9, characterized in that: The preset opening range is 1mm-3mm.

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