Characteristic length determination method and device for nonlinear seepage parameters of fractures

Abstract

The present application provides a method, device, electronic device and storage medium for distinguishing the characteristic length of nonlinear seepage parameters of fractures. In the method for distinguishing the characteristic length of nonlinear seepage parameters of fractures provided in the present application, by constructing a fracture device, the reference water inlet pressure P is changed at different inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ n If the length of the crack corresponding to the sampling point is less than the preset value, then the crack length corresponding to the sampling point of the crack is determined to be the characteristic length of the nonlinear seepage parameter of the crack. The characteristic length determination method of the nonlinear seepage parameter of the crack provided by the embodiment of the present application is conducive to the prediction of nonlinear seepage at the field scale and the study of the mechanism of nonlinear seepage scale effect; and the test process is simple and easy to understand and operate; it can obtain the characteristic length of the nonlinear seepage parameter of a single crack accurately, thereby effectively predicting the groundwater resources and preventing geological disasters.

Description

Technical Field

[0001] The present application relates to the technical field of bedrock fracture research, and in particular to a method, device, electronic device and storage medium for distinguishing characteristic length of nonlinear seepage parameters of fractures. Background Art

[0002] Bedrock fissures are one of the main aquifer media. Human activities such as underground space development, underground energy mining, and geological storage of nuclear waste will be affected by bedrock fissures. If the amount of water in the fissures is not reasonably evaluated before construction, serious geological disasters such as mines and water inrush are likely to occur. Therefore, mastering the seepage characteristics of bedrock fissures is an important basis for effectively predicting underground seepage, developing underground resources, and preventing geological disasters. However, due to the strong heterogeneity of the fissures, there is an obvious non-Darcy phenomenon in the seepage of bedrock fissures, that is, the seepage characteristics do not meet the traditional groundwater seepage theory. Therefore, it is urgent to conduct in-depth theoretical analysis on the nonlinear seepage law of bedrock fissures and study the changing characteristics and characterization methods of the nonlinear seepage process of bedrock fissures.

[0003] The characteristic length of the seepage parameter corresponds to the nonlinear seepage parameter and can approximately estimate the degree of nonlinearity. It can effectively predict the nonlinear flow relationship of bedrock fractures and predict the underground seepage process. The identification of the characteristic length of the seepage parameter has theoretical and engineering significance for human groundwater exploitation, large-scale underground activities, and geological disaster prevention and control.

[0004] At present, the study of nonlinear flow seepage parameters is generally carried out by making core samples, using rock psychological parameters and fluid physical parameters to fit the pressure gradient-flow relationship curve to obtain the corresponding nonlinear seepage parameters; however, due to the complexity of core sample production, the accuracy of the parameters may be insufficient. Or the nonlinear flow permeability coefficient of the dislocation zone is calculated based on the linear seepage coefficient, flow rate and water pressure changes; however, the nonlinear seepage coefficient calculated by this method is the nonlinear seepage coefficient of a specific length of fracture, which cannot accurately predict the amount of groundwater. Summary of the invention

[0005] The purpose of the embodiment of the present application is to provide a method, device, electronic device and storage medium for distinguishing the characteristic length of nonlinear seepage parameters of a fracture, by constructing a fracture device with adjustable fracture length, under different changes in the reference water inlet pressure P inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ nIf the crack length corresponding to the crack sampling point is less than the preset value, then the crack length corresponding to the crack sampling point is determined to be the characteristic length of the nonlinear seepage parameter of the crack. The characteristic length discrimination method of the crack nonlinear seepage parameter provided by the embodiment of the present application can obtain high-precision seepage parameters, and can obtain the characteristic length of the nonlinear seepage parameter under different crack lengths; it is conducive to the prediction of nonlinear seepage at the field scale and the mechanism research of the nonlinear seepage scale effect, and accurately predicts the groundwater volume to effectively prevent geological disasters.

[0006] In a first aspect, the present invention provides a method for determining the characteristic length of a nonlinear seepage parameter of a fracture, the method comprising: step 1: constructing a fracture device, and obtaining a plurality of fracture sampling points X from the fracture device; n Step 2: Take the reference water inlet pressure P inlet Inject water from the inlet of the fracture device. Step 3: Calculate the X n The corresponding nonlinear seepage proportional coefficient change rate δ n Step 4: Change the reference water inlet pressure P inlet Repeat steps 2 to 3 to obtain several fracture sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n Step 5: Determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n Step 6: If there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The fracture length at the fracture sampling point X is taken as the characteristic length of the nonlinear seepage parameter of the fracture; where the characteristic length is n The corresponding fracture length for which the nonlinear seepage parameter of the fracture does not change with increasing fracture scale.

[0007] In the above implementation process, the embodiment of the present application uses a self-affine fracture with natural fracture geometric characteristics to reflect the real fracture seepage scenario; and the length of the fracture can be changed by adjusting the device, and the measured data has high accuracy. inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ nIf the length of the crack corresponding to the crack sampling point is less than the preset value, the crack length corresponding to the crack sampling point is determined to be the characteristic length of the nonlinear seepage parameter of the crack. The characteristic length discrimination method of the nonlinear seepage parameter of the crack provided in the embodiment of the present application can obtain high-precision seepage parameters, and can obtain the characteristic length of the nonlinear seepage parameter under different crack lengths; it is conducive to the prediction of nonlinear seepage at the field scale and the mechanism research of the nonlinear seepage scale effect.

[0008] Optionally, in the embodiment of the present application, the calculation is performed with respect to the crack sampling point X n The corresponding nonlinear seepage proportional coefficient change rate δ n Includes: Calculate the crack sampling point X n Hydraulic gradient J n , and according to the hydraulic gradient J n Get the fracture sampling point X n Viscous permeability and inertial permeability According to the viscosity permeability and inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n .

[0009] In the above implementation process, by acquiring and monitoring the flow rate and water pressure, the two can be converted into physical quantities that characterize nonlinear seepage parameters. By drawing the curve relationship between the nonlinear seepage parameters and the flow distance and calculating the change rate of the nonlinear seepage scale-dependent model at each position, the X value of each fracture sampling point can be obtained. n The nonlinear seepage proportional coefficient change rate δ n ; Nonlinear seepage proportional coefficient change rate δ n Characterize the change of nonlinear seepage proportional coefficient. Through the study and calculation of the change rate of nonlinear proportional coefficient, the characteristic length of nonlinear seepage parameters can be determined; further, the nonlinear flow rate relationship of bedrock fractures can be effectively predicted, thereby accurately predicting the underground seepage process.

[0010] Optionally, in the embodiment of the present application, the crack sampling point X is calculated n Hydraulic gradient J n Includes: Get crack sampling point X n Water pressure P n ; By water pressure P n , reference water inlet pressure P inlet and the fracture sampling point X n Distance from entrance L n According to the formula: Calculate hydraulic gradient J n ; Where ρ is the density of water, g is the acceleration due to gravity, and i is a positive integer from 1 to n.

[0011] In the above implementation process, the water pressure P n , the reference water inlet pressure P inlet and the fracture sampling point X n The distance L between the inlet (i.e. the injection module) n Ability to obtain fracture sampling point X n Therefore, the characteristic length determination method of the nonlinear seepage parameters of the fracture provided in the embodiment of the present application can be obtained by n , the reference water inlet pressure P inlet and the distance L n The mechanical energy consumed by water to overcome frictional resistance when passing through a permeation path per unit length is obtained.

[0012] Optionally, in the embodiment of the present application, according to the viscosity permeability and inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n Includes: Based on viscosity permeability and inertial permeability Calculate the nonlinear seepage parameter ω; obtain the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated based on the nonlinear seepage parameter ω and the flow distance. n ; Among them, the flow distance is from the entrance to the fracture sampling point X n The distance between.

[0013] In the above implementation process, the Forchheimer equation is used to fit the pressure gradient and flow relationship curve to obtain the fracture sampling point X 1 , X 2 , X 3 ...viscous permeability and inertial permeability Get the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated according to the nonlinear seepage parameter ω and the flow distance. n ; Further, according to the nonlinear seepage proportional coefficient change rate δ n The characteristic length of the nonlinear seepage parameter is determined by the nonlinear seepage proportional coefficient change rate δ n When it is less than 0.5%, the crack length corresponding to the crack sampling point is used as the characteristic length of the nonlinear seepage parameter, thereby accurately finding the characteristic length of the nonlinear seepage parameter.

[0014] Optionally, in the embodiment of the present application, if the nonlinear seepage proportional coefficient change rate δ nIf both are greater than the preset percentage, the slit length of the slit device is increased and steps 1 to 6 are repeated.

[0015] In the above implementation process, when the method for determining the characteristic length of the nonlinear seepage parameter of the fracture provided in the embodiment of the present application fails to determine the characteristic length of the nonlinear seepage parameter, the fracture length in the fracture body of the fracture device provided in the embodiment of the present application can be adjusted to quickly increase the fracture length to continue to determine and calculate the characteristic length of the nonlinear seepage parameter.

[0016] Optionally, in the embodiment of the present application, it is determined whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , including: according to the current crack sampling point X n The corresponding nonlinear seepage proportional coefficient ω(x i ) and the next crack sampling point X n+1 The corresponding nonlinear seepage proportional coefficient ω(x i+1 ), according to the formula: Determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n .

[0017] In the above implementation process, the nonlinear seepage proportional coefficient change rate δ n The characteristic length of the nonlinear seepage parameter is compared with the preset percentage to achieve the discrimination of the characteristic length of the nonlinear seepage parameter; in practical applications, the preset percentage can be a quantity that varies with actual engineering needs; therefore, the method for discriminating the characteristic length of the nonlinear seepage parameter of the fracture provided in the embodiment of the present application is very beneficial to the prediction of nonlinear seepage at the field scale; the obtained characteristic length has theoretical and engineering significance for human groundwater exploitation, large-scale underground activities, and geological disaster prevention and control.

[0018] Optionally, in an embodiment of the present application, after constructing the fracture device, the characteristic length determination method of the fracture nonlinear seepage parameter further includes: testing whether the fracture device is leaking; and adjusting the water inlet pressure so that water enters the fracture device at a constant seepage rate.

[0019] In the above implementation process, after the fracture device is constructed, the fracture device is tested for leakage; after ensuring that the fracture device has no leakage, the fracture main body module is injected with water at a constant seepage rate, thereby ensuring that the obtained parameters are highly accurate.

[0020] In a second aspect, the present application provides a device for distinguishing the characteristic length of nonlinear seepage parameters of a fracture, the device comprising: a fracture device construction module, a nonlinear seepage proportional coefficient change rate calculation module, and a nonlinear seepage parameter characteristic length determination module. The fracture device construction module is used to execute step 1: construct a fracture device, and obtain a number of fracture sampling points X from the fracture device. n ; Nonlinear seepage proportional coefficient change rate calculation module, used to execute step 2: based on the reference water inlet pressure P inlet The water flow is injected from the inlet of the fracture device. The nonlinear seepage proportional coefficient change rate calculation module is also used to execute step 3: calculate the n The corresponding nonlinear seepage proportional coefficient change rate δ n The nonlinear seepage proportional coefficient change rate calculation module is also used to execute step 4: change the reference water inlet pressure P inlet Repeat steps 2 to 3 to obtain several fracture sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n The characteristic length determination module of the nonlinear seepage parameter is used to execute step 5: determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n ; The characteristic length determination module of the nonlinear seepage parameter is also used to execute step 6: if there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The fracture length at the fracture sampling point X is taken as the characteristic length of the nonlinear seepage parameter of the fracture; where the characteristic length is n The corresponding fracture length for which the nonlinear seepage parameter of the fracture does not change with increasing fracture scale.

[0021] In a third aspect, an embodiment of the present application provides an electronic device, comprising a memory and a processor, wherein the memory stores program instructions, and when the processor reads and runs the program instructions, it executes the steps in any of the above implementation methods.

[0022] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the steps in any of the above-mentioned implementation methods are executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the structure of a crack device provided in an embodiment of the present application;

[0026] Figure 3 A flow chart for determining the characteristic length of nonlinear seepage parameters of fractures provided in an embodiment of the present application;

[0027] Figure 4 A flow chart for obtaining a proportional coefficient provided in an embodiment of the present application;

[0028] Figure 5 A flow chart for obtaining hydraulic gradients at fracture sampling points provided in an embodiment of the present application;

[0029] Figure 6 A flow chart for obtaining viscous permeability and inertial permeability provided in an embodiment of the present application;

[0030] Figure 7 The flow rate at each fracture sampling point varies with the pressure gradient when the fracture length is 1 m provided in the embodiment of the present application;

[0031] Figure 8 A graph showing the relationship between nonlinear seepage parameters and migration distance when the fracture length is 1 m provided in the embodiment of the present application;

[0032] Fig. 9 The flow rate at each fracture sampling point varies with the pressure gradient when the fracture length is 2 m provided in the embodiment of the present application;

[0033] Fig.10 A graph showing the relationship between nonlinear seepage parameters and migration distance when the fracture length is 2 m is provided for the embodiment of the present application;

[0034] Fig.11 A schematic diagram of a module for a device for distinguishing characteristic length of nonlinear seepage parameters of fractures provided in an embodiment of the present application.

[0035] Icons: injection module-210; water injection pump-211; first valve-212; injection module pressure gauge-214; water inlet buffer box-216; fracture main body module-220; fracture main body module pressure gauge-221; fracture channel-222; fracture upper plate-226; fracture lower plate-224; discharge module-230; second valve-232; discharge module pressure gauge-234; flange-240; stabilizing column-260; exhaust valve-280. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram may 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 the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they may 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 the flowchart, and the combination of boxes in the block diagram and / or the flowchart, can be implemented by a dedicated hardware-based system that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0037] During the research process, the applicant discovered that there is an obvious scale effect of seepage in bedrock fissures, that is, as the scope of the working area increases, the seepage-related parameters will change. As the length of a single fracture increases, the nonlinear seepage parameters of the bedrock fractures will reach stability, and the fracture length at this time is called the characteristic length of the seepage parameters. When the scale of a single fracture exceeds the characteristic length, the nonlinear degree can be approximately estimated by the nonlinear seepage parameter corresponding to the characteristic length, thereby effectively predicting the nonlinear flow relationship of the bedrock fracture and predicting the underground seepage process. The identification of this characteristic length has theoretical and engineering significance for human groundwater exploitation, large-scale underground activities, and geological disaster prevention and control. At present, the research on the characteristic length of nonlinear seepage parameters has the problem that the obtained parameters are not accurate enough; and it is impossible to change the fracture length and conduct multiple experiments to obtain the characteristic length of the nonlinear seepage parameters.

[0038] Based on this, the method for distinguishing the characteristic length of nonlinear seepage parameters of fractures provided in the present application constructs a fracture device with adjustable fracture length, and changes the reference water inlet pressure P at different inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ n If the value is less than the preset value, the fracture length corresponding to the fracture sampling point is considered to be the characteristic length of the nonlinear seepage parameter of the fracture. This enables the prediction of nonlinear parameters of a single fracture at a larger scale, and promotes the research work on the upscaled nonlinear seepage mechanism.

[0039] Before introducing the present application, several concepts involved in the present application are briefly described first.

[0040] "Darcy's law" is a law that describes the linear relationship between the seepage velocity of water in rock and soil pores and the hydraulic gradient, also known as the linear seepage law.

[0041] "Seepage" refers to the movement of groundwater in the gaps between rock and soil.

[0042] "Non-linear seepage parameters" are also called non-Darcy seepage. When the fluid flows in the gaps in rock and soil, when the seepage velocity increases to a certain limit, the seepage velocity and pressure gradient are no longer linearly related, resulting in Darcy's law no longer being applicable. This flow is called non-linear seepage.

[0043] "Characteristic length of nonlinear seepage parameters". As the length of a single bedrock fracture increases, the nonlinear seepage parameters of the bedrock fracture will reach stability. The fracture length at this time is called the characteristic length of the nonlinear seepage parameters.

[0044] The “nonlinear seepage proportional coefficient change rate” represents the change of the nonlinear seepage proportional coefficient, which can be obtained by express.

[0045] “Viscous permeability” refers to the permeability in Darcy’s law, which refers to the inherent permeability of a medium to a fluid, and represents the momentum loss due to the viscosity of the fluid.

[0046] "Inertial permeability" refers to the permeability in the quadratic term in the Forchheimer equation, representing momentum loss due to the inertia of the fluid.

[0047] The "nonlinear seepage proportionality coefficient" is the quantitative relationship between the viscous permeability and the inertial permeability.

[0048] "Hydraulic gradient" is also called hydraulic slope or hydraulic grade, which refers to the ratio of the head loss along the infiltration path to the length of the infiltration path; it can be understood as the mechanical energy consumed by water flow through a unit length of infiltration path to overcome friction resistance; or the driving force that makes water flow at a certain flow rate to overcome friction; or the head drop value per unit distance along the water flow direction in the aquifer.

[0049] "Pressure head" refers to the water driving force caused by pressure, which is the value directly measured by the pressure gauge in the implementation of this application, that is, the water pressure. It should be noted that since the single crack of the crack device in the embodiment of this application is placed horizontally, there is no height change from upstream to downstream; that is, there is no position head, so the measured water pressure is the pressure head.

[0050] See also Figure 1 , Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. An electronic device 100 provided in an embodiment of the present application comprises: a processor 101 and a memory 102, wherein the memory 102 stores machine-readable instructions executable by the processor 101, and when the machine-readable instructions are executed by the processor 101, a characteristic length discrimination method for nonlinear seepage parameters of fractures as provided in the first aspect of the present application is executed.

[0051] The memory 102 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), etc. The memory 102 is used to store programs, and the processor 101 executes the program after receiving the execution instruction. The method executed by the electronic device 100 defined by the process disclosed in any embodiment of the present application can be applied to the processor 101, or implemented by the processor 101.

[0052] The processor 101 may be an integrated circuit chip with signal processing capability. The processor 101 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0053] Please see Figure 2 , Figure 2 A schematic structural diagram of a fissure device provided in an embodiment of the present application; the fissure device 200 comprises: an injection module 210, a discharge module 230 and a fissure body module 220; a flange 240 and a stabilizing column 260.

[0054] The injection module 210 includes a pressure gauge 214 , a water injection pump 211 , a first valve 212 , an injection module pressure gauge 214 and an inlet water buffer tank 216 .

[0055] The discharge module 230 includes a pressure relief valve 280 , a discharge module pressure gauge 234 , and a second valve 232 .

[0056] The fracture body module 220 includes a fracture upper plate 226, a fracture lower plate 224, a fracture channel 222, and a fracture module pressure gauge 221; the fracture length in the fracture body module 220 can be 1m, 2m, 3m, and the fracture length can be adjusted, and is not fixed and cannot be changed. When constructing the fracture, the electronic device 100 can input fracture geometric parameters such as fractal dimension into the self-affine software Synfrac to generate the surface XYZ coordinates of the fracture upper plate 226 and the fracture lower plate 224. The electronic device 100 intercepts the self-affine fracture curves with different roughness, and generates the fracture upper plate 226 and the fracture lower plate 224 through laser engraving technology, thereby completing the construction of the fracture.

[0057] It should be noted that the material of the fracture upper plate 226 and the fracture lower plate 224 in the fracture device provided in the embodiment of the present application can be acrylic; those skilled in the art can understand that since the permeability of acrylic material is extremely low, using acrylic material as the material of the fracture upper plate 226 and the fracture lower plate 224 can avoid the problem of water leakage from the fracture medium.

[0058] See also Figure 3 , Figure 3 A flow chart for determining the characteristic length of nonlinear seepage parameters of fractures provided in an embodiment of the present application; the method comprises:

[0059] Step S100: construct a crack device and obtain a number of crack sampling points X from the crack device n .

[0060] In the above step S100, the electronic device 100 constructs a crack device and obtains a number of crack sampling points X from the crack device. n Exemplarily, the electronic device 100 connects the injection module 210, the crack body module 220 and the discharge module 230 to form the crack device 200; it should be noted that when sampling is performed in the crack device provided in the present application, sampling points can be collected at fixed intervals; for example, the distance between each crack sampling point can be 20 cm, and can also be adjusted according to actual conditions, which are not listed here one by one.

[0061] Step S101: Using the reference water inlet pressure P inlet Water flow is injected from the inlet of the fracture device.

[0062] In the above step S101, the electronic device 100 adjusts the pressure of the water injection pump 211 to control the water inlet pressure of the fracture device; inlet Water is injected from the inlet of the fracture device to allow water to enter the fracture channel 222 of the fracture main module at a constant seepage flow rate; at the same time, the first valve 212 and the second valve 232 are controlled to keep the pressure difference of the fracture channel 222 stable. It should be noted that the water flows into the fracture device 200 from the injection module 210 and is discharged from the discharge module 230; in order to obtain the flow rate of the water flow, a flow meter can be set in the discharge module 230 to obtain the flow rate in the fracture through the flow meter.

[0063] Step S102: Calculate the crack sampling point X n The corresponding nonlinear seepage proportional coefficient change rate δ n .

[0064] In the above step S102, the crack sampling point X is calculated. n The corresponding nonlinear seepage proportional coefficient change rate δ n Those skilled in the art will appreciate that the nonlinear seepage proportional coefficient change rate represents the change of the nonlinear seepage proportional coefficient, which can be expressed as Represents; the nonlinear seepage proportional coefficient is the quantitative relationship between viscous permeability and inertial permeability; viscous permeability and inertial permeability are closely related to water pressure.

[0065] Step S103: Changing the reference water inlet pressure P inlet Repeat step S101 to step S102 to obtain a number of crack sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n .

[0066] In the above step S103, the injection module 210 of the fracture device 200 changes the reference water inlet pressure P inlet , repeat the above steps S101 to S102, thereby obtaining the nonlinear seepage proportional change rate δ corresponding to the fracture sampling points under different water pressures n .

[0067] Step S104: Determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n .

[0068] In the above step S104, the nonlinear seepage proportional change rate δ corresponding to the fracture sampling points under different water pressures is obtained through the above step S103. n , determine the nonlinear seepage ratio change rate δ n Whether there are crack sampling points less than the preset percentage. It should be noted that the preset percentage can be 0.5%. In practical applications, facing different engineering requirements, the percentage can vary; the 0.5% in the embodiment of the present application is only a specific preset standard, and the specific value corresponding to the preset percentage should not be a limitation on the protection scope of the embodiment of the present application.

[0069] Step S105: If there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The crack length at is taken as the characteristic length of the nonlinear seepage parameter of the crack.

[0070] In the above step S105, if there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , the crack length corresponding to the sampling point is taken as the characteristic length of the nonlinear seepage parameter; if the change rate of the nonlinear proportional coefficient corresponding to all crack sampling points is greater than the preset percentage, then the characteristic length of the nonlinear seepage parameter of the crack cannot be determined.

[0071] pass Figure 3It can be seen that the embodiment of the present application uses a self-affine fracture with natural fracture geometric characteristics to reflect the real fracture seepage scenario; and the length of the fracture can be changed by adjusting the device, and the measured data has high accuracy. inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ n If the length of the crack corresponding to the crack sampling point is less than the preset value, the crack length corresponding to the crack sampling point is determined to be the characteristic length of the nonlinear seepage parameter of the crack. The characteristic length discrimination method of the nonlinear seepage parameter of the crack provided in the embodiment of the present application can obtain high-precision seepage parameters, and can obtain the characteristic length of the nonlinear seepage parameter under different crack lengths; it is conducive to the prediction of nonlinear seepage at the field scale and the mechanism research of the nonlinear seepage scale effect.

[0072] See also Figure 4 , Figure 4 A flow chart for obtaining a proportional coefficient provided in an embodiment of the present application; the method comprises:

[0073] Step S200: Calculate the crack sampling point X n Hydraulic gradient J n , and according to the hydraulic gradient J n Get the fracture sampling point X n Viscous permeability and inertial permeability

[0074] In the above step S200, the hydraulic gradient J n It is a quantity related to water pressure. By setting a flow meter in the discharge system 230, the flow rate in the fracture can be obtained; the hydraulic gradient J can be obtained from the flow rate n , through the hydraulic gradient J n Viscous permeability can be obtained and inertial permeability It can be understood by those skilled in the art that "viscous permeability" refers to the permeability in Darcy's law, refers to the inherent permeability of the medium to the fluid, and characterizes the momentum loss caused by the viscosity of the fluid; "inertial permeability" refers to the permeability in the quadratic term in the Forchheimer equation, and characterizes the momentum loss caused by the inertia of the fluid.

[0075] Step S201: According to the viscosity permeability and inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n .

[0076] In the above step S201, according to the viscosity permeability and inertial permeability Calculate the fracture sampling point X n After obtaining a series of proportional coefficients, the relationship between the nonlinear seepage parameter and the flow distance can be plotted; it can be understood by those skilled in the art that the flow distance is the distance between the injection device and the sampling point. n The nonlinear seepage proportional coefficient change rate δ n .

[0077] pass Figure 4 It can be seen that by acquiring and monitoring the flow rate and water pressure, the two can be converted into physical quantities that characterize nonlinear seepage parameters. By drawing the curve relationship between the nonlinear seepage parameters and the flow distance and calculating the change rate of the nonlinear seepage scale-dependent model at each position, the X value of each fracture sampling point can be obtained. n The nonlinear seepage proportional coefficient change rate δ n ; Nonlinear seepage proportional coefficient change rate δ n Characterize the change of nonlinear seepage proportional coefficient. Through the study and calculation of the change rate of nonlinear proportional coefficient, the characteristic length of nonlinear seepage parameters can be determined; further, the nonlinear flow rate relationship of bedrock fractures can be effectively predicted, thereby accurately predicting the underground seepage process.

[0078] Please see Figure 5 , Figure 5 A flow chart for obtaining the hydraulic gradient of a fracture sampling point provided in an embodiment of the present application; the method comprises:

[0079] Step S300: Obtaining the fracture sampling point X n Water pressure P n ;

[0080] In the above step S300, the fracture body module 220 in the fracture device 200 provided in the embodiment of the present application includes a plurality of fracture body module pressure gauges 221, and the electronic device 100 obtains the water pressure P of the fracture body module pressure gauge 221. n It should be noted that in practical applications, the position and number of pressure gauges can be adjusted according to actual needs.

[0081] Step S301: Water pressure P n , reference water inlet pressure P inlet and the fracture sampling point X n Distance from entrance L n According to the formula: Calculate hydraulic gradient J n .

[0082] In the above step S301, the water pressure P measured by the fracture body module pressure gauge 221 in the fracture body module 220 is n , the reference water inlet pressure P obtained by the pressure gauge in the injection module 210 inlet and the fracture sampling point X n The distance between the injection module 210 (usually referred to as the migration distance) is used to calculate the hydraulic gradient J n .

[0083] Exemplarily, the electronic device 100 obtains the crack sampling point X 1 , X 2 , X 3 ...X n The reading P of the pressure gauge 221 1 , P 2 , P 3 ...P n ; Reference water inlet pressure P inlet ; Transport distance L n According to the formula Calculate the fracture sampling point X 1 , X 2 , X 3 ...X n Hydraulic gradient J 1 , J 2 , J 3 ……J n ; Where ρ is the density of water, g is the acceleration due to gravity, and i is a positive integer from 1 to n.

[0084] pass Figure 5 It can be seen that through the water pressure P n , reference water inlet pressure P inlet and the fracture sampling point X n The distance L from the inlet (i.e. injection module) n Ability to obtain fracture sampling point X n Therefore, the characteristic length determination method of the nonlinear seepage parameters of the fracture provided in the embodiment of the present application can be obtained by n , reference water inlet pressure P inlet and the distance L n The mechanical energy consumed by water to overcome frictional resistance when passing through a permeation path per unit length is obtained.

[0085] See also Figure 6 , Figure 6 A flowchart for obtaining viscous permeability and inertial permeability provided in an embodiment of the present application; the method comprises:

[0086] Step S400: According to the viscosity permeability and inertial permeability Calculate the nonlinear seepage parameter ω;

[0087] In the above step S400, when drawing the crack sampling point X 1 , X 2 , X 3 ...X n The electronic device 100 uses the Forchheimer equation to fit the pressure gradient and flow relationship curve to obtain the fracture sampling point X 1 , X 2 , X 3 ...viscous permeability and inertial permeability Those skilled in the art can understand that when the Forchheimer equation is used to fit the pressure gradient and flow relationship curve, the Forchheimer equation relationship is: Where J is the hydraulic gradient; μ is the dynamic viscosity of water, in pa·s; V is the specific flow rate, in m 3 / s;k v is the viscous permeability, in m 2 ;k i is the inertial permeability, in m.

[0088] It should be noted that when using the Forchheimer equation for fitting, Origin software or other data analysis software can be used in combination. This type of software can obtain fitting parameters and goodness of fit. Goodness of fit is the degree of match between experimental data and fitting data. The closer the goodness of fit value is to 1, the higher the degree of match between experimental data and fitting data. The nonlinear seepage parameters used in fitting are the relationship between the inertia term coefficient and the viscosity term coefficient: Where ω is the nonlinear seepage parameter, in m -2 .

[0089] Step S401: Obtain crack sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated based on the nonlinear seepage parameter ω and the flow distance. n ; Among them, the flow distance is from the entrance to the fracture sampling point X n The distance between.

[0090] In the above step S401, the electronic device 100 obtains the crack sampling point X n The flow distance is the distance between the injection module 210 (i.e., the inlet) of the fracture device 200 and the fracture sampling point, and the flow distance is called the migration distance. v and inertial permeability k i Calculate the fracture sampling point X using the relation1 , X 2 , X 3 ...X n Nonlinear seepage proportionality coefficient ω 1 ,ω 2 ,ω 3 ...ω n ; Draw the relationship curve between the nonlinear seepage parameter ω and the migration distance and calculate the change rate of the nonlinear seepage parameter ω at each location. For example, the fracture sampling point X i The rate of change of the nonlinear seepage parameter at can be calculated according to the formula Calculate; where ω(x i ) is X i The nonlinear seepage parameter at ω(x i+1 ) is the same as X i Adjacent X i+1 In the process of obtaining, the change rate of nonlinear seepage parameters at all fracture sampling points is calculated in turn. If δ(x i ) is greater than 0.5%, let i=i+1; that is, when the change rate of the nonlinear seepage parameter of the fracture is greater than 0.5%, it is considered that the characteristic length of the nonlinear seepage parameter of the fracture cannot be determined, and it is necessary to continue to calculate the change rate of the nonlinear seepage parameter of the next fracture sampling point. It can be understood by those skilled in the art that in the embodiment of the present application, the nonlinear seepage parameter change rate of 0.5% is used as the judgment standard. In practical applications, the nonlinear seepage parameter change rate is determined based on engineering requirements, that is, 0.5% is not the only unchanging standard. The nonlinear seepage parameter change rate judgment standard of 0.5% in the embodiment of the present application should not be understood as a limitation on the judgment standard.

[0091] pass Figure 6 It can be seen that in the embodiment of the present application, the Forchheimer equation is used to fit the pressure gradient and flow relationship curve to obtain the fracture sampling point X 1 , X 2 , X 3 ...viscous permeability and inertial permeability Get the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated based on the nonlinear seepage parameter ω and the flow distance. n ; Further, according to the nonlinear seepage proportional coefficient change rate δ n The characteristic length of the nonlinear seepage parameter is determined by the nonlinear seepage proportional coefficient change rate δ nWhen it is less than 0.5%, the crack length corresponding to the crack sampling point is used as the characteristic length of the nonlinear seepage parameter, thereby accurately finding the characteristic length of the nonlinear seepage parameter, which can greatly promote the research on the mechanism of nonlinear seepage scale effect.

[0092] In an optional embodiment, if the nonlinear seepage proportional coefficient change rate δ n If both are greater than a preset percentage, the slit length of the slit device is increased, and steps S100 to S105 are repeated.

[0093] That is to say, the nonlinear seepage proportional coefficient change rate δ of all fracture sampling points is completed. n After calculation, the nonlinear seepage proportional coefficient change rate δ of all fracture sampling points n If they are all greater than the preset percentage, then it is determined that the characteristic length of the nonlinear seepage parameter of the fracture cannot be determined, and it is necessary to continue to change the length of the fracture in the middle fracture body module 220 of the fracture device 200, continue to obtain several fracture sampling points, and calculate the change rate of the nonlinear seepage parameter of each fracture sampling point.

[0094] It should be noted that in the embodiment of the present application, the length of the fissure channel 222 in the middle fissure body module 220 of the fissure device 200 is changed, the stabilizing column 260 is removed through the flange 240, and the new 1m long fissure body is connected to the fissure body module 220 through the flange 240 and the stabilizing column 260, so as to achieve a rapid increase in the fissure length.

[0095] It can be seen from this that when the method for determining the characteristic length of the nonlinear seepage parameter of the fracture provided in the embodiment of the present application fails to determine the characteristic length of the nonlinear seepage parameter, the fracture length in the fracture body of the fracture device provided in the embodiment of the present application can be adjusted to quickly increase the fracture length to continue to determine and calculate the characteristic length of the nonlinear seepage parameter.

[0096] In an optional embodiment, it is determined whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n Includes: According to the current crack sampling point X n The corresponding nonlinear seepage proportional coefficient ω(x i ) and the next crack sampling point X n+1 The corresponding nonlinear seepage proportional coefficient ω(x i+1 ) According to the formula: Determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n ; Wherein, i is a positive integer from 1 to n.

[0097] It should be noted that in the process of obtaining, the change rate of the upper nonlinear seepage parameters of all fracture sampling points is calculated in turn. If δ(x i ) is greater than 0.5%, let i=i+1; that is, when the change rate of the nonlinear seepage parameter of the fracture is greater than 0.5%, it is considered that the characteristic length of the nonlinear seepage parameter of the fracture cannot be determined, and it is necessary to continue to calculate the change rate of the nonlinear seepage parameter of the next fracture sampling point. It can be understood by those skilled in the art that in the embodiment of the present application, the nonlinear seepage parameter change rate of 0.5% is used as the judgment standard. In practical applications, the nonlinear seepage parameter change rate is determined based on engineering requirements, that is, 0.5% is not the only unchanging standard. The nonlinear seepage parameter change rate judgment standard of 0.5% in the embodiment of the present application should not be understood as a limitation on the judgment standard.

[0098] It can be seen that the nonlinear seepage proportional coefficient change rate δ n The characteristic length of the nonlinear seepage parameter is compared with the preset percentage to achieve the discrimination of the characteristic length of the nonlinear seepage parameter; in practical applications, the preset percentage can be a quantity that varies with actual engineering needs; therefore, the method for discriminating the characteristic length of the nonlinear seepage parameter of the fracture provided in the embodiment of the present application is very beneficial to the prediction of nonlinear seepage at the field scale; the obtained characteristic length has theoretical and engineering significance for human groundwater exploitation, large-scale underground activities, and geological disaster prevention and control.

[0099] In an optional embodiment, after constructing the fracture device, the method further includes: testing whether the fracture device is leaking; and adjusting the water inlet pressure so that water enters the fracture device at a constant seepage rate.

[0100] For example, in the embodiment of the present application, when testing whether the fracture device 200 is leaking, the water injection pump 211 and the first valve 210 are opened. The second closing valve 232 is closed to inject water into the water inlet buffer box 216, and the exhaust valve 280 is opened to exhaust air at the same time. When the fracture main body system is filled with water, the exhaust valve 280 is closed to test whether the fracture main body module 220 is leaking. When there is no water flow outflow from the fracture device 200 and the pressure readings of all pressure gauges (injection module pressure gauge 214, fracture main body module pressure gauge 221 and discharge module pressure gauge 234) are stable, it is considered that the fracture main body module 220 is not leaking. Further, the pressure of the water injection pump 211 is adjusted to control the water inlet pressure, so that water enters the fracture channel 222 of the fracture main body module 220 at a constant seepage flow rate, and the first valve 212 and the second valve 232 are controlled to keep the pressure difference of the fracture channel 222 stable.

[0101] It can be seen that after the fracture device is constructed, the fracture device is tested for leakage; after ensuring that the fracture device has no leakage, the fracture main body module is injected with water at a constant seepage rate; thereby ensuring that the obtained parameters are highly accurate.

[0102] In an optional embodiment, a single crack with a length of 1 m is used as an example. The sampling ports are set at the sampling points on the side of the crack channel 222. The first sampling point is set at 10 cm from the stable column 260 in the crack main body module 220, and then a sampling point X is set every 20 cm. 1 , X 2 , X 3 ...X n ; In the embodiment of the present application, five crack sampling points are taken, namely: X 1 , X 2 , X 3 , X 4 , X 5 . Then each sampling port is connected to a separate fracture body module pressure gauge 221 through a conduit, so as to obtain the water pressure at each fracture sampling point. The fracture device 100 is constructed, and the fracture body module of the fracture device 100 is tested to have no water leakage problem. The water inlet pressure is controlled by adjusting the pressure of the water injection pump 211, so that water enters the fracture channel 222 of the fracture body module 220 at a constant seepage flow rate; the valve is controlled to keep the pressure difference of the fracture channel 222 stable.

[0103] Furthermore, through the crack sampling point X 1 , X 2 , X 3 , X 4 , X 5 The pressure gauge obtains the water pressure P at that location 1 , P 2 , P 3 , P 4 , P 5 , and according to the formula Calculate hydraulic gradient J 1 , J 2 , J 3 , J 4 , J 5 It should be noted that J in the formula i X is the crack sampling point i The hydraulic gradient of i X is the crack sampling point i The pressure gauge 221 shows the value in Pa; P inlet is the reading of the fracture entrance pressure gauge 221, in Pa; L i X is the crack sampling point i The length from the entrance is in meters; ρ is the density of water in kg / m 3 ; g is the acceleration due to gravity, unit is m 2 / s.

[0104] The flow rate V in the fracture is obtained by the flow meter in the discharge module 230. The inlet pressure of the fracture device is changed, and the above steps are repeated to obtain the fracture sampling point X. 1 , X 2 , X 3 , X 4 , X 5 A series of flow rates and hydraulic gradients at the fracture sampling points, the electronic device 100 plots the fracture sampling point X 1 , X 2 , X 3 , X 4 , X 5 For the relationship curve between pressure gradient and flow rate, please refer to Figure 7 , Figure 7 The flow rate at each fracture sampling point varies with the pressure gradient when the fracture length provided in the embodiment of the present application is 1 m; the pressure gradient and flow rate relationship curve is calculated using the Forchheimer equation according to the formula Perform fitting to obtain the crack sampling point X 1 , X 2 , X 3 , X 4 , X 5 Viscous permeability and inertial permeability Viscous permeability and inertial permeability The results are shown in Table 1. It should be noted that in the formula, J is the hydraulic gradient; μ is the dynamic viscosity of water, in pa·s; V is the flow rate, in m / s; k v is the viscous permeability, in m 2 ;k i is the inertial permeability, in m.

[0105] Table 1

[0106] <![CDATA[X 1 ]]> <![CDATA[X 2 ]]> <![CDATA[X 3 ]]> <![CDATA[X 4 ]]> <![CDATA[X 5 ]]> <![CDATA[k v (m 2 )]]> 5.69E-09 4.82E-09 4.67E-09 4.61E-09 4.58E-09 <![CDATA[k i (m)]]> 1.06E-06 1.31E-06 1.37E-06 1.41E-06 1.42E-06 <![CDATA[w(m -2 )]]> 2473700 3915508 4305852 4488251 4587498

[0107] Furthermore, the nonlinear seepage viscous permeability and inertial permeability Calculate the nonlinear seepage parameter ω 1 ,ω 2 ,ω 3 ,ω 4 ,ω 5 , and draw the relationship curve between nonlinear seepage parameters and flow distance. Figure 8 , Figure 8 The nonlinear seepage parameter changes with the migration distance when the fracture length provided in the embodiment of the present application is 1m; Figure 8In the figure, D = 2.3, e = 3.34 mm, where D is the fractal dimension, which is used to describe the complexity of the fluctuation of the crack channel 222; e is the average opening, which refers to the average value of the distance from the crack upper plate 226 to the crack lower plate 224. Figure 8 It can be seen that the nonlinear seepage parameter close to the injection module 210 is smaller; and the nonlinear seepage parameter increases with the increase of the migration distance.

[0108] According to the fitting results, the rate of change of nonlinear seepage parameters with scale is calculated, and the nonlinear seepage parameter characteristic length discriminant is used for discrimination, δ(x 1 )=58.29%,δ(x 2 )=9.97%,δ(x 3 )=4.24%,δ(x 4 )=2.21%. Due to the change rate of nonlinear seepage parameters δ(x 4 )=2.21%>0.5%; therefore, the characteristic length of the nonlinear seepage parameters cannot be obtained, and it is necessary to perform fracture upscaling nonlinear flow detection.

[0109] The stabilizing column 260 is removed through the flange 240, and a new 1m long fracture main body module 210 is connected to the fracture main body module 210 through the flange 240 and the stabilizing column 260; the fracture length is rapidly increased, and a 2m long fracture device is constructed. After the fracture length is increased to 2m, the fracture sampling points are increased to 10, which are X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 Repeat the above steps to obtain the fracture sampling point X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 The relationship between pressure gradient and flow rate at the Fig. 9 , Fig. 9 The flow rate at each fracture sampling point varies with the pressure gradient when the fracture length is 2 m provided in the embodiment of the present application; Fig. 9 It can be seen that as the flow rate increases, the pressure gradient also increases.

[0110] The electronic device 100 uses the Forchheimer equation to fit the pressure gradient and flow relationship curve to obtain the fracture sampling point X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 Viscous permeability and inertial permeability The results are shown in Table 2. Furthermore, the nonlinear seepage parameter ω is calculated 1 ,ω 2 ,ω 3 ,ω 4 ,ω 5 ,ω 6 ,ω 7 ,ω 8 ,ω 9 ,ω 10 The electronic device 100 draws a curve of the relationship between the nonlinear seepage parameter and the migration distance. Fig.10 , Fig.10 The embodiment of the present application provides a graph showing the relationship between the nonlinear seepage parameters and the migration distance when the fracture length is 2 m; Fig.10 In the figure, D = 2.3, e = 3.34 mm, where D is the fractal dimension, which is used to describe the complexity of the fluctuation of the crack channel 222; e is the average opening, which refers to the average value of the distance from the crack upper plate 226 to the crack lower plate 224. Fig.10 It can be seen that with the increase of migration distance, the nonlinear seepage parameters of the corresponding fracture sampling points first increase rapidly, then enter a slow increase stage, and finally tend to be stable.

[0111] Table 2

[0112] <![CDATA[X 1 ]]> <![CDATA[X 2 ]]> <![CDATA[X 3 ]]> <![CDATA[X 4 ]]> <![CDATA[X 5 ]]> <![CDATA[X 6 ]]> <![CDATA[X 7 ]]> <![CDATA[X 8 ]]> <![CDATA[X 9 ]]> <![CDATA[X 10 ]]> <![CDATA[k v (m 2 )]]> 5.69E-09 4.82E-09 4.67E-09 4.61E-09 4.58E-09 4.56E-09 4.54E-09 4.53E-09 4.53E-09 4.52E-09 <![CDATA[k i (m)]]> 1.06E-06 1.31E-06 1.37E-06 1.41E-06 1.42E-06 1.43E-06 1.44E-06 1.45E-06 1.45E-06 1.45E-06 <![CDATA[w(m -2 )]]> 2473700 3915508 4305852 4488251 4587498 4658771 4705725 4744631 4768861 4782100

[0113] Calculate the rate of change of nonlinear seepage parameters with scale, δ(x 5 )=1.55%,δ(x 6 )=1.01%,δ(x 7 )=0.83%,δ(x 8 )=0.51%,δ(x 9 )=0.28%. According to the nonlinear seepage parameter characteristic length discriminant, δ(x 9 )=0.28%<0.5%, therefore, the crack sampling point X 10 The corresponding fracture length is the nonlinear seepage characteristic length of this single fracture.

[0114] In the above implementation process, by constructing a crack device with adjustable crack length, the reference water inlet pressure P is changed at different inlet The nonlinear seepage proportional coefficient change rate δ of the fracture sampling point is calculated by n If there is a nonlinear seepage proportional coefficient change rate δ n If the length of the crack corresponding to the crack sampling point is less than the preset value, the crack length corresponding to the crack sampling point is determined to be the characteristic length of the nonlinear seepage parameter of the crack. The characteristic length discrimination method of the nonlinear seepage parameter of the crack provided in the embodiment of the present application can obtain high-precision seepage parameters, and can obtain the characteristic length of the nonlinear seepage parameter under different crack lengths; it is conducive to the prediction of nonlinear seepage at the field scale and the mechanism research of the nonlinear seepage scale effect.

[0115] Please see Fig.11 , Fig.11 This is a module schematic diagram of a device for distinguishing the characteristic length of nonlinear seepage parameters of fractures provided in an embodiment of the present application. The device 300 includes: a fracture device construction module 310, a nonlinear seepage proportional coefficient change rate calculation module 320, and a nonlinear seepage parameter characteristic length determination module 330.

[0116] The fracture device construction module 310 is used to execute step 1: construct a fracture device and obtain a number of fracture sampling points X from the fracture device. n ; Nonlinear seepage proportional coefficient change rate calculation module, used to execute step 2: based on the reference water inlet pressure P inlet Water flow is injected from the inlet of the fracture device.

[0117] The nonlinear seepage proportional coefficient change rate calculation module 320 is also used to perform step 3: calculate the n The corresponding nonlinear seepage proportional coefficient change rate δ n .

[0118] The nonlinear seepage proportional coefficient change rate calculation module 320 is also used to execute step 4: changing the reference water inlet pressure P inlet Repeat steps 2 to 3 to obtain several fracture sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n .

[0119] The characteristic length determination module 330 of the nonlinear seepage parameter is used to execute step 5: determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n .

[0120] The characteristic length determination module 330 of the nonlinear seepage parameter is also used to execute step 6: if there is a nonlinear seepage proportional coefficient change rate δn The number of crack sampling points X that are less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The fracture length at the fracture sampling point X is taken as the characteristic length of the nonlinear seepage parameter of the fracture; where the characteristic length is n The corresponding fracture length for which the nonlinear seepage parameter of the fracture does not change with increasing fracture scale.

[0121] In an optional embodiment, the nonlinear seepage proportional coefficient change rate calculation module 320 calculates the nonlinear seepage proportional coefficient change rate corresponding to the fracture sampling point X. n The corresponding nonlinear seepage proportional coefficient change rate δ n The nonlinear seepage proportional coefficient change rate calculation module 320 calculates the fracture sampling point X n Hydraulic gradient J n , and according to the hydraulic gradient J n Get the fracture sampling point X n Viscous permeability and inertial permeability The nonlinear seepage proportional coefficient change rate calculation module 320 calculates the nonlinear seepage proportional coefficient change rate according to the viscous permeability and inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n .

[0122] In an optional embodiment, the nonlinear seepage proportional coefficient change rate calculation module 320 calculates the fracture sampling point X n Hydraulic gradient J n Includes: Get crack sampling point X n Water pressure P n ; Nonlinear seepage proportional coefficient change rate calculation module 320 is based on water pressure P n , reference water inlet pressure P inlet and the fracture sampling point X n Distance from entrance L n According to the formula: Calculate hydraulic gradient J n ; Where ρ is the density of water, g is the acceleration due to gravity, and i is a positive integer from 1 to n.

[0123] In an optional embodiment, in the embodiment of the present application, the nonlinear seepage proportional coefficient change rate calculation module 320 calculates the nonlinear seepage proportional coefficient change rate according to the viscous permeability. and inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ nThe nonlinear seepage proportional coefficient change rate calculation module 320 calculates the nonlinear seepage proportional coefficient change rate according to the viscosity permeability and inertial permeability Calculate the nonlinear seepage parameter ω; obtain the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated based on the nonlinear seepage parameter ω and the flow distance. n ; Among them, the flow distance is from the entrance to the fracture sampling point X n The distance between.

[0124] In an optional embodiment, if the characteristic length determination module 330 of the nonlinear seepage parameter determines that the nonlinear seepage proportional coefficient change rate δ n If both are greater than the preset percentage, the slit length of the slit device is increased and steps 1 to 6 are repeated.

[0125] In an optional embodiment, the characteristic length determination module 330 of the nonlinear seepage parameter determines whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n , including: a characteristic length determination module 330 of nonlinear seepage parameters according to the current fracture sampling point X n The corresponding nonlinear seepage proportional coefficient ω(x i ) and the next crack sampling point X n+1 The corresponding nonlinear seepage proportional coefficient ω(x i+1 ) According to the formula: Determine whether there is a nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n .

[0126] In an optional embodiment, after constructing the fracture device, the characteristic length determination method of the fracture nonlinear seepage parameter further includes: the fracture device construction module 310 tests whether the fracture device is leaking; and adjusts the water inlet pressure to allow water to enter the fracture device at a constant seepage rate.

[0127] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer program instructions, and when the computer program instructions are read and executed by a processor, the steps in any of the above implementation methods are executed.

[0128] The computer-readable storage medium may be a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or any other medium that can store program codes. The storage medium is used to store the program, and the processor executes the program after receiving the execution instruction. The method executed by the electronic terminal of the process definition disclosed in any embodiment of the present invention can be applied to the processor or implemented by the processor.

[0129] In the 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 the devices or units can be electrical, mechanical or other forms.

[0130] In addition, 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.

[0131] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0132] Alternatively, the present invention may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the present invention may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part.

[0133] The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0134] In this article, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0135] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the characteristic length of nonlinear seepage parameters of fractures, characterized in that: The method includes: Step 1: Construct a fracture device and obtain a number of fracture sampling points X from the fracture device n ; Step 2: Take the reference water inlet pressure P inlet injecting water from the inlet of the slit device; Step 3: Calculate the fracture sampling point X n The corresponding nonlinear seepage proportional coefficient change rate δ n ; Step 4: Change the reference water inlet pressure P inlet Repeat step 2 to step 3 to obtain a number of fracture sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n ; Step 5: Determine whether there is the nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n ; Step 6: If there is a nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The fracture length at is taken as the characteristic length of the nonlinear seepage parameter of the fracture; Wherein, the characteristic length is the crack sampling point X n The corresponding fracture length for which the nonlinear seepage parameter of the fracture does not change with increasing fracture scale.

2. The method according to claim 1, characterized in that The calculation and the fracture sampling point X n The corresponding nonlinear seepage proportional coefficient change rate δ n ,include: Calculate the fracture sampling point X n Hydraulic gradient J n , and according to the hydraulic gradient J n Get the crack sampling point X n Viscous permeability and inertial permeability According to the viscous permeability and the inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n .

3. The method according to claim 2, characterized in that The calculation of the crack sampling point X n Hydraulic gradient J n ,include: Get the crack sampling point X n Water pressure P n ; The water pressure P n , the reference water inlet pressure P inlet and the fracture sampling point X n The distance L from the entrance n According to the formula: Calculate the hydraulic gradient J n ; Where ρ is the density of water, g is the acceleration due to gravity, and i is a positive integer from 1 to n.

4. The method according to claim 2, characterized in that: The viscosity permeability and the inertial permeability Calculate the fracture sampling point X n The nonlinear seepage proportional coefficient change rate δ n ,include: According to the viscous permeability and the inertial permeability Calculate the nonlinear seepage parameter ω; Get the crack sampling point X n The nonlinear seepage proportional coefficient change rate δ is calculated according to the nonlinear seepage parameter ω and the flow distance. n Wherein, the flow distance is from the inlet to the crack sampling point X n The distance between.

5. The method according to claim 1, characterized in that If the nonlinear seepage proportional coefficient change rate δ n If both are greater than the preset percentage, the slit length of the slit device is increased, and steps 1 to 6 are repeated.

6. The method according to claim 1, characterized in that The determination of whether there is a nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n ,include: According to the current crack sampling point X n The corresponding nonlinear seepage proportional coefficient ω(x i ) and the next crack sampling point X n+1 The corresponding nonlinear seepage proportional coefficient ω(x i+1 ) According to the formula: Determine whether there is the nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n ; Wherein, i is a positive integer from 1 to n.

7. The method according to claim 1, characterized in that After said constructing the slit device, said method further comprises: Testing whether the crack device is leaking; The water inlet pressure is adjusted so that water enters the fracture device at a constant seepage rate.

8. A device for distinguishing characteristic length of nonlinear seepage parameters of fractures, the device comprising: Fracture device construction module, nonlinear seepage proportional coefficient change rate calculation module, nonlinear seepage parameter characteristic length determination module; The fracture device construction module is used to perform step 1: construct a fracture device and obtain a number of fracture sampling points X from the fracture device. n ; The nonlinear seepage proportional coefficient change rate calculation module is used to perform step 2: taking the reference water inlet pressure P inlet injecting water from the inlet of the slit device; The nonlinear seepage proportional coefficient change rate calculation module is also used to perform step 3: calculate the nonlinear seepage proportional coefficient change rate of the fracture sampling point X n The corresponding nonlinear seepage proportional coefficient change rate δ n ; The nonlinear seepage proportional coefficient change rate calculation module is also used to execute step 4: changing the reference water inlet pressure P inlet Repeat step 2 to step 3 to obtain a number of fracture sampling points X n The corresponding nonlinear seepage proportional coefficient change rate δ n ; The characteristic length determination module of the nonlinear seepage parameter is used to perform step 5: determine whether there is a nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n ; The characteristic length determination module of the nonlinear seepage parameter is also used to execute step 6: if there is a nonlinear seepage proportional coefficient change rate δ n The crack sampling point X is less than the preset percentage n , then the nonlinear seepage proportional coefficient change rate δ n The number of crack sampling points X that are less than the preset percentage n The crack length at the crack sampling point X is taken as the characteristic length of the nonlinear seepage parameter of the crack; wherein the characteristic length is the length of the crack sampling point X. n The corresponding fracture length for which the nonlinear seepage parameter of the fracture does not change with increasing fracture scale.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory stores program instructions, and when the processor runs the program instructions, the steps in the method according to any one of claims 1 to 7 are executed.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the steps in the method according to any one of claims 1 to 7 are executed.

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