Shale fluid phase change feature evaluation method and device, electronic equipment and storage medium

Abstract

The application provides a shale fluid phase change feature evaluation method and device, electronic equipment and a storage medium. A corresponding multi-scale pore model is established by obtaining pore size distribution parameters in a shale pore system, the composition of the fluid in each pore is obtained, and the initial dew point temperature and / or bubble point temperature can be determined by the initial physical property parameters corresponding to each composition. The balance physical property parameters in the corresponding pore balance state are determined, and the effective pore size of each pore is determined. The actual dew point temperature and / or bubble point temperature is obtained, and the phase change feature of the shale pore system is determined. The actual dew point temperature and / or actual bubble point temperature distribution of the system can be accurately obtained, the influence of the pore size distribution on the phase change feature is analyzed, and the accuracy of the specific pore phase change feature evaluation in the shale fluid system is improved.

Description

Technical Field

[0001] This application relates to oil and gas development technology, and in particular to a method, apparatus, electronic device and storage medium for evaluating phase change characteristics of shale fluids. Background Technology

[0002] In the oil and gas development field, accurate prediction of the phase transition characteristics of fluids in shale pores is helpful in establishing production plans, predicting inter-well dynamics, and is also the foundation for improving ultimate recovery. Current methods for determining the phase transition characteristics of shale fluids typically involve randomly selecting a pore in a porous system, calculating the dew point temperature and / or bubble point temperature of that pore, and using the actual dew point temperature and / or actual bubble point temperature of that pore as the actual dew point temperature and / or actual bubble point temperature of the system. This is then used to analyze the phase transition characteristics of the fluid in the shale pore system.

[0003] However, these methods are difficult to accurately obtain the specific actual dew point temperature and / or actual bubble point temperature distribution of the system, and are difficult to analyze the influence of pore size distribution on phase transition characteristics, especially when analyzing fluids in micro-nano pores. Summary of the Invention

[0004] This application provides a method, apparatus, electronic device, and storage medium for evaluating phase change characteristics of shale fluids, in order to solve the problem of low accuracy in evaluating specific pore phase change characteristics within shale fluid systems.

[0005] Firstly, this application provides a method for evaluating the phase transition characteristics of shale fluids, including:

[0006] The pore size distribution parameters in the shale pore system are obtained, a multi-scale pore model is established based on the pore size distribution parameters, and the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition are obtained based on the multi-scale pore model.

[0007] Based on the initial physical property parameters, determine the initial dew point temperature and / or initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions.

[0008] Based on the equilibrium physical property parameters, calculate the effective pore size of each pore in the shale pore system;

[0009] Based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system;

[0010] The phase transition characteristics of the shale pore system are determined based on the actual dew point temperature and / or actual bubble point temperature of each pore.

[0011] As an optional implementation, determining the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions based on the initial physical property parameters includes:

[0012] Based on the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition, the free energy corresponding to each pore in the shale pore system is determined.

[0013] Based on the free energy corresponding to each pore in the shale pore system, the total free energy of the shale pore system is determined, and the equilibrium state parameters of the shale pore system are determined based on the total free energy.

[0014] Based on the equilibrium state parameters, the equilibrium composition of the fluid in each pore of the shale pore system is determined, as well as the equilibrium physical property parameters of each component in the equilibrium composition.

[0015] As an optional implementation, calculating the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters includes:

[0016] Based on the aforementioned equilibrium physical property parameters, determine the adsorption capacity of each pore in the shale pore system;

[0017] The thickness of the adsorption layer corresponding to each pore is determined based on the adsorption amount of each pore.

[0018] The effective pore size of each pore in the shale pore system is determined based on the adsorption layer thickness corresponding to each pore.

[0019] As an optional implementation, determining the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature includes:

[0020] Determine the fluid phase state and initial equilibrium constant corresponding to each fluid component in each pore of the shale pore system;

[0021] Based on the fluid phase state and initial equilibrium constant, determine the mole fraction of each fluid component in each pore;

[0022] Determine the initial capillary force, and based on the initial capillary force and the thickness of the adsorption layer, determine the gas-liquid two-phase density in each pore, and calculate the actual capillary force based on the calculated gas-liquid two-phase density.

[0023] The actual capillary force is used to indicate the intermolecular interaction force and capillary pressure in the corresponding pore.

[0024] Based on the actual capillary force and the thickness of the adsorption layer, the gas-liquid two-phase fugacity of each fluid component in each pore is determined, and the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system is determined based on the gas-liquid two-phase fugacity.

[0025] As an optional implementation, after determining the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, the method further includes:

[0026] Based on the fluid composition and phase of each pore in the shale pore system, determine the mole fraction of each fluid component in each pore.

[0027] The total mole fraction of each pore is determined based on the mole fraction of each fluid component in each pore.

[0028] Determine whether the total mole fraction of each pore is the first value. If it is determined that the total mole fraction of the pore is not the first value, then based on the determined actual dew point temperature and / or actual bubble point temperature, iteratively update the actual dew point temperature and / or actual bubble point temperature to the initial physical property parameters of the corresponding pore, and trigger the execution of the steps of determining the initial dew point temperature and / or initial bubble point temperature, and the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters.

[0029] If the total mole fraction of the pores is determined to be the first value, then the step of determining the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore is triggered.

[0030] Secondly, this application provides a device for evaluating the phase transition characteristics of shale fluids, the device comprising:

[0031] The model building module is used to obtain pore size distribution parameters in the shale pore system and to build a multi-scale pore model based on the pore size distribution parameters.

[0032] An initialization module is used to obtain the composition of the fluid in each pore of the shale pore system, as well as the initial physical property parameters corresponding to each composition, based on the multi-scale pore model.

[0033] The equilibrium parameter determination module is used to determine the initial dew point temperature and / or initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions, based on the initial physical property parameters.

[0034] The size calculation module is used to calculate the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters.

[0035] A temperature determination module is used to determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature.

[0036] The phase transition characteristic determination module is used to determine the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore.

[0037] As an optional implementation, the equilibrium parameter determination module determines the specific method by which it determines the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters, including:

[0038] Based on the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition, the free energy corresponding to each pore in the shale pore system is determined.

[0039] Based on the free energy corresponding to each pore in the shale pore system, the total free energy of the shale pore system is determined, and the equilibrium state parameters of the shale pore system are determined based on the total free energy.

[0040] Based on the equilibrium state parameters, the equilibrium composition of the fluid in each pore of the shale pore system is determined, as well as the equilibrium physical property parameters of each component in the equilibrium composition.

[0041] As an optional implementation, the size calculation module calculates the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters in a specific way, including:

[0042] Based on the aforementioned equilibrium physical property parameters, determine the adsorption capacity of each pore in the shale pore system;

[0043] The thickness of the adsorption layer corresponding to each pore is determined based on the adsorption amount of each pore.

[0044] The effective pore size of each pore in the shale pore system is determined based on the adsorption layer thickness corresponding to each pore.

[0045] As an optional implementation, the temperature determination module determines the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system according to the effective pore size and the initial dew point temperature and / or initial bubble point temperature, including:

[0046] Determine the fluid phase state and initial equilibrium constant corresponding to each fluid component in each pore of the shale pore system;

[0047] Based on the fluid phase state and initial equilibrium constant, determine the mole fraction of each fluid component in each pore;

[0048] Determine the initial capillary force, and based on the initial capillary force and the thickness of the adsorption layer, determine the gas-liquid two-phase density in each pore, and calculate the actual capillary force based on the calculated gas-liquid two-phase density.

[0049] The actual capillary force is used to indicate the intermolecular interaction force and capillary pressure in the corresponding pore.

[0050] Based on the actual capillary force and the thickness of the adsorption layer, the gas-liquid two-phase fugacity of each fluid component in each pore is determined, and the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system is determined based on the gas-liquid two-phase fugacity.

[0051] As an optional implementation, the device further includes a verification module, which is used to determine the mole fraction of each fluid component in each pore in the shale pore system based on the fluid composition and fluid phase of each pore in the shale pore system after the temperature determination module determines the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system according to the effective pore size and the initial dew point temperature and / or initial bubble point temperature.

[0052] The total mole fraction of each pore is determined based on the mole fraction of each fluid component in each pore.

[0053] Determine whether the total mole fraction of each pore is the first value. If it is determined that the total mole fraction of the pore is not the first value, then based on the determined actual dew point temperature and / or actual bubble point temperature, iteratively update the actual dew point temperature and / or actual bubble point temperature to the initial physical property parameters of the corresponding pore, and trigger the execution of the steps of determining the initial dew point temperature and / or initial bubble point temperature, and the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters.

[0054] If the total mole fraction of the pores is determined to be the first value, then the step of determining the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore is triggered.

[0055] Thirdly, this application also provides an electronic device, comprising:

[0056] At least one processor; and

[0057] A memory communicatively connected to the at least one processor; wherein,

[0058] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method as described in the first aspect.

[0059] Fourthly, this application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method described in the first aspect.

[0060] The shale fluid phase transition characteristic evaluation method, apparatus, electronic equipment, and storage medium provided in this application establish a corresponding multi-scale pore model by acquiring pore size distribution parameters in the shale pore system, obtaining the fluid composition in each pore, and the initial physical property parameters corresponding to each composition, thereby determining the initial dew point temperature and / or bubble point temperature, as well as the equilibrium physical property parameters under the corresponding pore equilibrium state, and further determining the effective pore size of each pore, obtaining the actual dew point temperature and / or bubble point temperature, and thus determining the phase transition characteristics of the shale pore system. It can accurately obtain the specific actual dew point temperature and / or actual bubble point temperature distribution of the system, and analyze the influence of pore size distribution on phase transition characteristics, thereby improving the accuracy of evaluating specific pore phase transition characteristics in the shale fluid system. Attached Figure Description

[0061] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0062] Figure 1 This is a schematic diagram illustrating an application scenario of the shale fluid phase transition characteristic evaluation method disclosed in an embodiment of the present invention;

[0063] Figure 2 This is a schematic flowchart of a method for evaluating the phase transition characteristics of shale fluids disclosed in an embodiment of the present invention;

[0064] Figure 3 This is a flowchart illustrating another method for evaluating the phase transition characteristics of shale fluids disclosed in an embodiment of the present invention;

[0065] Figure 4 This is a schematic diagram of the structure of a shale fluid phase change characteristic evaluation device disclosed in an embodiment of the present invention;

[0066] Figure 5 This is a schematic diagram of another shale fluid phase change characteristic evaluation device disclosed in an embodiment of the present invention;

[0067] Figure 6This is a schematic diagram of the structure of an electronic device for evaluating the phase change characteristics of shale fluids, as disclosed in an embodiment of the present invention.

[0068] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0069] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0070] Please see Figure 1 , Figure 1 This is a schematic diagram illustrating an application scenario of the shale fluid phase transition characteristic evaluation method disclosed in this invention, used to demonstrate the structural distribution of pores in a shale pore system. For example... Figure 1 As shown, the shale pore system can include multiple pores of different sizes. The physical properties of each pore may not be completely consistent with the overall parameters of the system. Therefore, the fluid conditions in each pore can be specifically determined, thereby obtaining the actual dew point temperature and / or actual bubble point temperature distribution corresponding to each pore, and analyzing the influence of pore size distribution on phase change characteristics, thus improving the accuracy of the evaluation of phase change characteristics of specific pores in the shale fluid system.

[0071] Example 1

[0072] Please see Figure 2 , Figure 2 This is a schematic diagram of a shale fluid phase transition characteristic evaluation method disclosed in an embodiment of the present invention. Figure 2 As shown, the method includes:

[0073] S101. Obtain the pore size distribution parameters in the shale pore system, establish a multi-scale pore model based on the pore size distribution parameters, and obtain the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition based on the multi-scale pore model.

[0074] S102. Based on the initial physical property parameters, determine the initial dew point temperature and / or the initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions.

[0075] The initial dew point temperature and / or initial bubble point temperature determined in the current step are only initial values ​​determined based on the initial physical property parameters of the fluid in each pore. Subsequently, the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system can be determined based on these initial values. The validity of the actual dew point temperature and / or actual bubble point temperature can also be determined. When the data does not meet the equilibrium conditions, iterative updates can be performed. At this time, steps S102-S104 will be repeated, and the initial dew point temperature and / or initial bubble point temperature will be updated to the currently determined actual dew point temperature and / or actual bubble point temperature. Through a series of iterative processes, the accuracy of the actual dew point temperature and / or actual bubble point temperature can be improved, so that the actual dew point temperature and / or actual bubble point temperature can accurately reflect the equilibrium state of the corresponding pore. For details, please refer to the relevant descriptions in the subsequent embodiments.

[0076] S103. Calculate the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters.

[0077] Because of the adsorption effect of fluid in each pore, the size of the pore itself may not accurately reflect the phase change state of the pore fluid. Therefore, the adsorption amount and adsorption layer thickness should be determined according to the physical model of the adsorption effect, so as to obtain the effective pore size and obtain a more accurate actual dew point temperature and / or actual bubble point temperature.

[0078] S104. Based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system.

[0079] As mentioned above, the main parameters to be determined in this application are the actual dew point temperature and / or actual bubble point temperature of each pore. This temperature can be determined by the initial dew point temperature and / or initial bubble point temperature, or the initial dew point temperature and / or initial bubble point temperature obtained in each iteration update, and the aforementioned determined effective pore size. The actual dew point temperature and / or actual bubble point temperature should reflect the equilibrium state of the corresponding pores. Therefore, the validity of the determined actual dew point temperature and / or actual bubble point temperature can also be verified, as detailed in other embodiments.

[0080] S105. Determine the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore.

[0081] As an optional implementation, determining the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions based on the initial physical property parameters includes:

[0082] Based on the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition, the free energy corresponding to each pore in the shale pore system is determined.

[0083] Based on the free energy corresponding to each pore in the shale pore system, the total free energy of the shale pore system is determined, and the equilibrium state parameters of the shale pore system are determined based on the total free energy.

[0084] Based on the equilibrium state parameters, the equilibrium composition of the fluid in each pore of the shale pore system is determined, as well as the equilibrium physical property parameters of each component in the equilibrium composition.

[0085] The specific form of free energy can be Helmholtz free energy. According to thermodynamic principles, when a system is in equilibrium, its free energy is at its minimum. The state with the minimum total Helmholtz free energy is the global phase equilibrium state. Therefore, based on the Helmholtz free energy of each pore, the total Helmholtz free energy can be determined, and a corresponding optimization method can be established to determine the conditions for achieving its minimum value, such as through a dynamic tunneling global optimization method. Typically, the calculation methods for the Helmholtz free energy of bulk pores and nanopores may differ; please refer to the formula selection method in Example 3 for details.

[0086] By determining the free energy corresponding to each pore in the shale pore system, the equilibrium state parameters of the shale pore system under the condition of minimum total free energy are obtained. Then, the equilibrium components corresponding to the fluid in each pore of the shale pore system, as well as the equilibrium physical property parameters corresponding to each component in the equilibrium components, are determined. This allows the equilibrium physical property parameters to be correlated with the state of each pore, thereby improving the accuracy and effectiveness of the equilibrium physical property parameters and the accuracy of the phase transition characteristics evaluation of the shale fluid system.

[0087] As an optional implementation, calculating the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters includes:

[0088] Based on the aforementioned equilibrium physical property parameters, determine the adsorption capacity of each pore in the shale pore system;

[0089] The thickness of the adsorption layer corresponding to each pore is determined based on the adsorption amount of each pore.

[0090] The effective pore size of each pore in the shale pore system is determined based on the adsorption layer thickness corresponding to each pore.

[0091] As mentioned earlier, due to the adsorption effect of fluid in each pore, the size of the pores themselves may not accurately reflect the phase transition state of the pore fluid. Therefore, based on the physical model of the adsorption effect and the equilibrium property parameters determined in the preceding steps, the adsorption amount and adsorption layer thickness can be further determined, thereby obtaining the effective pore size and thus obtaining a more accurate actual dew point temperature and / or actual bubble point temperature.

[0092] By balancing physical property parameters, the actual adsorption capacity and adsorption layer thickness of each pore in the shale pore system can be determined, thereby obtaining the corresponding effective pore size. This allows for more accurate dew point temperature and / or bubble point temperature, thus improving the accuracy of phase change characteristic evaluation of the shale fluid system.

[0093] As an optional implementation, determining the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature includes:

[0094] Determine the fluid phase state and initial equilibrium constant corresponding to each fluid component in each pore of the shale pore system;

[0095] The initial equilibrium parameter is an estimated initial value. To ensure that the final actual dew point temperature and / or actual bubble point temperature calculated by the system can accurately reflect the equilibrium state of the system, the latest initial equilibrium parameter will also be obtained during the iterative update process. That is, during the iterative update step, the initial equilibrium parameter is also constantly updated, which can more accurately reflect the equilibrium state of the system during the iteration process.

[0096] Based on the fluid phase state and initial equilibrium constant, determine the mole fraction of each fluid component in each pore;

[0097] The mole fraction can be used to determine whether the system is in equilibrium, as can be seen in other embodiments.

[0098] Determine the initial capillary force, and based on the initial capillary force and the thickness of the adsorption layer, determine the gas-liquid two-phase density in each pore, and calculate the actual capillary force based on the calculated gas-liquid two-phase density.

[0099] The actual capillary force is used to indicate the intermolecular interaction force and capillary pressure in the corresponding pore.

[0100] Based on the actual capillary force and the thickness of the adsorption layer, the gas-liquid two-phase fugacity of each fluid component in each pore is determined, and the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system is determined based on the gas-liquid two-phase fugacity.

[0101] The fugacity of each component's gas-liquid two-phase system can be used to determine the error. When the error is less than a preset threshold, such as 10 to the power of -3, the temperature is calculated based on the corresponding equilibrium constant in this step; otherwise, the aforementioned equilibrium constant needs to be iteratively updated.

[0102] By determining the actual capillary force of each pore, and then determining the intermolecular interaction force and capillary pressure in the corresponding pore, it can be used to determine the gas-liquid two-phase fugacity of each fluid component in each pore, and calculate the error based on the gas-liquid two-phase fugacity, thereby calculating or updating the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system, thereby improving the accuracy of the phase change characteristic evaluation of the shale fluid system.

[0103] This embodiment establishes a corresponding multi-scale pore model by acquiring pore size distribution parameters in the shale pore system, obtaining the fluid composition within each pore, and the initial physical property parameters corresponding to each composition. This allows for the determination of the initial dew point temperature and / or bubble point temperature, as well as the equilibrium physical property parameters under the corresponding pore equilibrium state. Furthermore, it determines the effective pore size of each pore, obtains the actual dew point temperature and / or bubble point temperature, and thereby determines the phase transition characteristics of the shale pore system. This accurately obtains the specific actual dew point temperature and / or actual bubble point temperature distribution of the system and analyzes the influence of pore size distribution on phase transition characteristics, improving the accuracy of evaluating specific pore phase transition characteristics within the shale fluid system.

[0104] Example 2

[0105] Please see Figure 3 , Figure 3 This is a schematic diagram of another method for evaluating the phase transition characteristics of shale fluids disclosed in an embodiment of the present invention. Figure 3 As shown, the method includes:

[0106] S201. Obtain the pore size distribution parameters in the shale pore system, establish a multi-scale pore model based on the pore size distribution parameters, and obtain the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition based on the multi-scale pore model.

[0107] S202. Based on the initial physical property parameters, determine the initial dew point temperature and / or the initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions.

[0108] S203. Calculate the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters.

[0109] S204. Based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system.

[0110] S205. Based on the fluid composition and fluid phase of each pore in the shale pore system, determine the mole fraction of each fluid component in each pore.

[0111] S206. Determine the total mole fraction of each pore based on the mole fraction of each fluid component in each pore.

[0112] S207. Determine whether the total mole fraction of each pore is the first value;

[0113] In practical applications, the first value can be 1. Since determining the actual dew point temperature and / or the actual bubble point temperature requires estimating an initial temperature K value based on the system's physical properties, this value may not be the actual equilibrium value during the iteration process. Therefore, to improve accuracy, the corresponding data cannot be directly output. Instead, it is necessary to check whether the total mole fraction in the pores meets the requirement. For example, when the first value is 1, if the total mole fraction is not 1, it means that the corresponding pores have not reached equilibrium, and the K value is not real. Therefore, the K value needs to be iterated to obtain the gas-liquid equilibrium constant under equilibrium conditions, thereby improving the accuracy of determining the phase transition characteristics of the shale pore system.

[0114] S208. If it is determined that the total mole fraction of the pores is not the first value, then based on the determined actual dew point temperature and / or actual bubble point temperature, the actual dew point temperature and / or actual bubble point temperature are iteratively updated to the initial physical property parameters of the corresponding pores, and the step of determining the initial dew point temperature and / or initial bubble point temperature, and the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state are triggered.

[0115] As mentioned above, when it is determined that the system may not be in equilibrium, the step of updating the temperature can be performed iteratively according to the secant method. For details, please refer to the selected formula and related description in Example 3.

[0116] S209. If the total mole fraction of pores is determined to be the first value, then the step of determining the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore is triggered.

[0117] When the system is determined to be in equilibrium, the accuracy of the corresponding parameters improves, which in turn allows for the determination of the phase transition characteristics of the shale pore system, thus improving the accuracy of the phase transition characteristic evaluation of the shale fluid system. Alternatively, to ensure algorithm convergence, when the number of iterations reaches a preset number, corresponding determination steps can be performed based on the current actual dew point temperature and / or actual bubble point temperature.

[0118] It should be noted that for a detailed description of S201-204, please refer to the relevant description in Embodiment 1, which will not be repeated here.

[0119] This embodiment improves the effectiveness of dew point temperature and bubble point temperature data by determining the mole fraction of fluid in pores and further determining the total mole fraction, thereby determining whether the conditions indicated by the first numerical value are met and whether the actual dew point temperature and / or actual bubble point temperature need to be updated, thereby improving the accuracy of phase change characteristic evaluation of shale fluid systems.

[0120] Example 3

[0121] This embodiment selects and illustrates the methods described in this application based on specific application cases and formulas to show the difference. In this embodiment, the step numbers are not preceded by "S".

[0122] Step 1: Establish a multi-scale model of shale micro- and nano-scale pores and determine the molar composition of each fluid component in the system. Step 2: Determine the fluid composition in each pore size based on a novel pore size-dependent equation of state (PR-C). Step 3: Establish a model for calculating the adsorption layer thickness and calculate the effective pore size for each pore. Step 4: Calculate the phase transition characteristic parameters in the pores, perform normalization calculations, and obtain the final phase parameters.

[0123] The pore size-dependent equation of state used in step 2 is modified in three ways compared to the traditional equation of state: it considers the influence of pore size on the free volume of molecules and the potential energy of interactions between fluid molecules, and it considers the influence of the interaction between pore wall molecules and fluid molecules. The interaction between fluid molecules and wall molecules in the nanoscale pores of shale significantly alters the phase behavior of the fluid; therefore, compared to the traditional equation of state, the pore size-dependent equation of state can more accurately characterize phase features.

[0124] In step 3, because within the micro-nano pore size range, the smaller the pore size, the stronger the interaction between the fluid and the pore walls, the larger the proportion of adsorbed phase and the smaller the bulk phase. Molecules adsorbed on the pore walls do not participate in the flow, thus significantly reducing the effective pore diameter and its impact on capillary pressure cannot be ignored. To more accurately calculate the phase transition characteristics in nanopores, the influence of the adsorbed layer thickness must be considered when calculating capillary forces.

[0125] In step 4, since the dew point and bubble point of the fluid are greatly affected by the interaction forces in the nanoporous state, the point where the first bubble appears and the point where the first droplet appears in a system are the bubble / dew point of the fluid. In the case of multi-size pores, the bubble / dew point always appears first in the smallest pore. Therefore, when performing the final bubble-dew point calculation, the phase characteristics of the system are characterized by the phase characteristics in the smallest pore size.

[0126] Step 1 includes: Step 101: Obtain the pore size distribution parameters of the shale pores, divide the shale pores into bulk regions (pore size d1) and nanopore regions (pore sizes d2, d3, d4...dnk), and establish a multi-scale pore model. The pore size distribution parameters can be obtained from core experiments.

[0127] Bulk phase regions generally refer to fractures and macropores in the shale matrix; nanopores refer to pores with a diameter of less than 50 nm in the matrix, where fluid characteristics are altered due to confinement effects. See details... Figure 1 The relevant description of the shale pore system is as follows. Step 102: Obtain the fluid composition (n1, n2, n3....nNC) and the basic physical properties of each component, including critical point pressure (Pcb), temperature (Tcb), eccentricity factor, molar mass, etc.

[0128] As a specific example, the porous model can be set up to consist of four pore sizes. The diameter d1 of the bulk pore model is 10 μm, and the sizes of the three nanopores are d2 = 10 nm, d3 = 15 nm, and d4 = 20 nm, respectively. Furthermore, it is assumed that the fluid in the model is a three-component mixture of methane, ethane, and propane, with a molar composition of methane:ethane:propane = 70%:20%:10%. The relevant fluid properties can be obtained from the NIST database. The basic physical properties of the fluid involved in this example are shown in Table 1.

[0129] Table 1. Fluid physical properties

[0130]

[0131] Step 2 includes: Step 201: Based on the composition and pressure of the system fluid, assign an initial value to the dew point (bubble point) temperature using empirical formulas. Preferably, the Antoine formula is introduced, with formula (1) used for calculating the bubble point temperature and formula (2) used for calculating the initial value of the dew point temperature:

[0132]

[0133]

[0134] In the formula, a, b, and c are the Antonio constants of each component, P is the pressure, and x and y are the mole fractions of the light and heavy components, respectively.

[0135] The light and heavy components can be determined according to the actual application scenario. The usual reference indicators are component density or molecular mass.

[0136] Step 202: Calculate the fluid composition at different pore sizes under the system temperature, pressure and fluid composition by minimizing the global free energy.

[0137] Different pore sizes may have different adsorption capacities for different fluid components, and the adsorption capacity is related to the system's physical properties.

[0138] Preferably, multi-size nanoscale pores require a specific description of the fluid at each pore size, and the modified pore size-related equation of state is shown in equation (3):

[0139]

[0140] This equation of state is used to determine the composition of the fluid in different pore sizes under the aforementioned temperature and pressure conditions. Where P is the system pressure; R is the universal gas constant; T is the system temperature; v is the molar volume of the fluid mixture; x i a represents the mole fraction of component i, which in turn reflects the mole fraction of the system. p and b p These are the constraint correction energy and volume parameters of the equation of state, calculated using formulas (4)-(9).

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147] Where, k ij The parameters are binary interaction parameters, calculated by the mixing rule; ω is the eccentricity factor, which is dimensionless; r p Where σ is the pore radius. i σ is the molecular diameter of fluid component i. ij Let i be the average molecular diameter of components i and j, and the calculation formula is (10)-(11).

[0148]

[0149]

[0150] For component i, θ i It is a geometric term, F pr，i It is the fraction of fluid attracted by the pore surface under random distribution, and the calculation formula is as follows:

[0151]

[0152]

[0153] Preferably, the chemical potential of each component in the bulk pores is calculated using formula (14):

[0154]

[0155] According to the equilibrium criterion, in equilibrium, the system naturally satisfies the following: the chemical potential of any component i is equal among all phases in all regions, and the pressure between phases in each region is equal, that is:

[0156] μ i,nano (T,ρ nano ,x nano ,r p )=μ i,b (T,ρ b ,x b i = 1, 2, ..., NC (15)

[0157] Where NC is the number of components.

[0158] Equation 15 is used to verify whether the system meets the equilibrium state based on the chemical potential obtained from Equation 14. If it is determined that the system meets the equilibrium state according to Equation 15, the conditions determined by Equation 4-13 are substituted into Equation 3 for calculation.

[0159] According to thermodynamic principles, when a system is in equilibrium, its free energy is at its minimum. The state with the minimum total Helmholtz free energy is the global phase equilibrium state. The total Helmholtz free energy of the system is shown in equation (16):

[0160]

[0161] The formulas for calculating the Helmholtz free energy in the bulk region and the Helmholtz free energy in the nanopores are as follows:

[0162]

[0163]

[0164] By minimizing the total Helmholtz free energy of the system using the dynamic tunneling global optimization method, the equilibrium composition of each region can be obtained. The constraints for solving this system of Diophantine equations are molar conservation and volume conservation.

[0165]

[0166]

[0167]

[0168] Under isothermal conditions:

[0169] T b =T p,1 =T p,2 =...=T p,NP (twenty two)

[0170] In phase equilibrium, the pressure in every region of the system is equal, that is:

[0171]

[0172]

[0173] Step 3: Based on the fluid composition in different pores output in Step 2, establish a calculation model for the adsorption layer thickness, and calculate the effective pore size for each pore, specifically including:

[0174] Step 301: Calculate the adsorption amount in different pores. When the fluid in the pores is multi-component, competitive adsorption will occur. Preferably, the adsorption amount in each pore is calculated using the multi-component adsorption equation extended by Langmuir.

[0175]

[0176] Among them, V ik，add and V ik，m They represent d respectively k The adsorption capacity at equilibrium and the maximum adsorption capacity at the scale, P i b represents the equilibrium pressure of component i. L , where i is the isothermal adsorption constant, z i This represents the mole fraction of component i. The relevant parameters can be obtained from relevant literature in the field.

[0177] Step 302: Calculate the adsorption layer thickness based on the adsorption amount. The calculation formulas are (26)-(27):

[0178]

[0179]

[0180] Among them, t k,add For d k Adsorption layer thickness at size V k,add V is the adsorption volume. k,m v represents the maximum adsorption capacity. k,M t is the molar volume of the liquid. k,m For the maximum adsorption layer thickness, N A This represents the Avogadro constant.

[0181] Due to the presence of the adsorption membrane, the effective pore radius changes. Step 303 involves calculating the effective pore radius using the following formula:

[0182]

[0183] Where, r k,e t represents the effective pore size. add Where σ is the thickness of the adsorption layer ss Let be the collision diameter of the molecules on the wall.

[0184] Step 4: Calculate the phase transition characteristic parameters in the smallest pore size, and after normalization, obtain the final phase parameters, namely the dew point and bubble point of the multi-size pore system.

[0185] Since the confinement effect significantly affects the phase change characteristics of fluids, the smaller the pore size, the smaller the dew point value. The temperature at which the first droplet appears in the system is the dew point temperature. In multi-sized pores, the pore with the smallest pore size is the first to produce droplets. Therefore, the dew point temperature in the smallest pore can be used as the dew point temperature of multi-sized pores.

[0186] Specifically:

[0187] Step 401: Confirm the pore size, temperature, fluid composition, and basic physical properties of each component in each pore, and estimate the initial K value using the Wilson equation. Specifically, refer to the relevant data in Table 1 and estimate according to Equation 29.

[0188]

[0189] Equation 29 can be used to determine the specific phase state, thereby simplifying subsequent calculations. The value calculated by 29 is substituted into 30. If it meets the requirements, it means that the bubble point is required and the current phase is liquid. If it does not meet the requirements, it is substituted into 31. If 31 meets the requirements, it means that the dew point is required and the current phase is gaseous. If 31 does not meet the requirements, it means that the phase is gas-liquid mixture.

[0190] When calculating bubble point and dew point, the vaporization fractions are 0 and 1, respectively, and the simplified formula (30) is:

[0191]

[0192]

[0193] Step 402: Calculate the composition of the liquid (gas) phase within the smallest pore size. The formula for calculating the mole fraction of component i in the gas-liquid two-phase system is:

[0194] If the fluid is determined to be in a single-phase state according to Equation 29, then only one of the corresponding formulas is used, and will not be elaborated further.

[0195]

[0196]

[0197] The supplementary relation is:

[0198]

[0199] The mole fractions of the gas and liquid phases were solved using the Rcahford-Rice equation, i.e., the flash evaporation equations 32-34, and the Newton-Raphson numerical method.

[0200] Step 403: Calculate the gas-liquid two-phase density and compressibility factor in the pores, taking into account capillary forces and the thickness of the adsorption layer.

[0201] First, assign an initial value P to the capillary force. 0cap Solving for the gas and liquid terms, compressibility factor, and density, the compressibility of the liquid or gas phase can be determined by the following relationship:

[0202]

[0203]

[0204] Among them, Z L and Z V These are the compressibility coefficients for the liquid and gas phases, respectively.

[0205]

[0206]

[0207] Since the influence of capillary pressure in nanopores cannot be ignored, the pressure in the gas and liquid phases is different from that in conventional reservoirs.

[0208] Therefore, in step 404: based on the calculated gas-liquid two-phase density, the capillary pressure is calculated using the Young-Laplace equation. Assuming the liquid is the wetting phase, preferably, the calculation formula is as follows:

[0209]

[0210] In the formula, σ represents the interfacial tension (N / m); θ is the contact angle between the wetting phase and the nanopore, which is taken as 0° when considering the adsorption layer. Under nanoporous conditions, the interfacial tension is also affected by the pore size. The formula for calculating the interfacial tension is:

[0211]

[0212]

[0213] In the formula, δ is the Tolma length, which describes the curvature dependence of surface tension, and V S σ is the molar solid volume; σ∞ represents the surface tension of a surface with an infinite radius of curvature.

[0214]

[0215] In the formula, χ i ρ is the parachor constant of component i. l and ρ g It is the molar density. The value of parachor can be obtained from the literature or calculated empirically using key attributes.

[0216]

[0217] Compare the calculated result with the initial capillary pressure value in step 403. If it is greater than the error range, update the capillary pressure and return to step 403.

[0218] Step 405: Calculate the gas-liquid two-phase fugacity considering capillary forces, adsorption layers, and intermolecular interactions, determine whether the system is in equilibrium, and update the equilibrium constant K.

[0219] Preferably, the formula for calculating the fugacity of the gas-liquid two-phase system is:

[0220]

[0221]

[0222] Calculate the fugacity of each component in the gas-liquid two-phase system, compare the error of the fugacity of each component, and determine whether the error is less than 10. -3 ,Right now

[0223]

[0224] If the value is greater than the error threshold, the balance constant K is recalculated, and the process returns to step 402. Steps 402-405 are K-loops, which iteratively calculate until the value is less than the error threshold, at which point the final balance constant K is obtained and the process proceeds to step 406.

[0225] It should be noted that the equilibrium state calculated earlier was under fixed temperature and pressure. In the second cycle, the temperature was changed, and the value from the first cycle was borrowed. After the second cycle was completed, the first cycle was re-entered for calculation. Only when the results of the two cycles were the same was the result considered to be true.

[0226] Step 406: Calculate whether the sum of the mole fractions of each component in the gas phase (liquid phase) is 1. If not, update the temperature T and return to step 2 until the temperature error is less than the error threshold. The output temperature is then the dew point (bubble point) temperature. Preferably, to improve the speed and accuracy of the iterative calculation, the secant method is used to update the temperature T. The iteration rule is as follows:

[0227]

[0228] T k =T k+1 +δT (48)

[0229] Therefore, an interconnected multi-scale pore model was established to restore the true physical properties of shale cores to the greatest extent possible, and a method for calculating the phase characteristics of fluids under multi-scale conditions was established: first, the fluid composition in different pores under interconnected conditions was determined, and the final phase characteristics were determined by the fluid composition in order to obtain the calculation results that are closest to the phase transition characteristics in real shale pores.

[0230] This embodiment establishes a corresponding multi-scale pore model by acquiring pore size distribution parameters in the shale pore system, obtaining the fluid composition within each pore, and the initial physical property parameters corresponding to each composition. This allows for the determination of the initial dew point temperature and / or bubble point temperature, as well as the equilibrium physical property parameters under the corresponding pore equilibrium state. Furthermore, it determines the effective pore size of each pore, obtains the actual dew point temperature and / or bubble point temperature, and thereby determines the phase transition characteristics of the shale pore system. This accurately obtains the specific actual dew point temperature and / or actual bubble point temperature distribution of the system and analyzes the influence of pore size distribution on phase transition characteristics, improving the accuracy of evaluating specific pore phase transition characteristics within the shale fluid system.

[0231] Example 4

[0232] This invention also provides a shale fluid phase transition characteristic evaluation device to implement the aforementioned method. Please refer to [link to relevant documentation]. Figure 4 , Figure 4 This is a schematic diagram of the structure of a shale fluid phase change characteristic evaluation device disclosed in an embodiment of the present invention. Figure 4 As shown, based on any other embodiment, the apparatus includes:

[0233] Model building module 41 is used to obtain pore size distribution parameters in the shale pore system and build a multi-scale pore model based on the pore size distribution parameters.

[0234] Initialization module 42 is used to obtain the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition based on the multi-scale pore model.

[0235] The equilibrium parameter determination module 43 is used to determine the initial dew point temperature and / or the initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions, based on the initial physical property parameters.

[0236] Size calculation module 44 is used to calculate the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters;

[0237] Temperature determination module 45 is used to determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature.

[0238] The phase transition characteristic determination module 46 is used to determine the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore.

[0239] By acquiring pore size distribution parameters in the shale pore system, a corresponding multi-scale pore model is established. The composition of the fluid within each pore and the initial physical property parameters corresponding to each composition can be obtained to determine the initial dew point temperature and / or bubble point temperature, as well as the equilibrium physical property parameters under the corresponding pore equilibrium state. This allows for the determination of the effective pore size of each pore, obtaining the actual dew point temperature and / or bubble point temperature, and thus determining the phase transition characteristics of the shale pore system. This enables accurate acquisition of the specific actual dew point temperature and / or actual bubble point temperature distribution of the system, and analysis of the influence of pore size distribution on phase transition characteristics, thereby improving the accuracy of evaluating specific pore phase transition characteristics within the shale fluid system.

[0240] As an optional implementation, the equilibrium parameter determination module 43 determines the specific method by which it determines the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters, including:

[0241] Based on the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition, the free energy corresponding to each pore in the shale pore system is determined.

[0242] Based on the free energy corresponding to each pore in the shale pore system, the total free energy of the shale pore system is determined, and the equilibrium state parameters of the shale pore system are determined based on the total free energy.

[0243] Based on the equilibrium state parameters, the equilibrium composition of the fluid in each pore of the shale pore system is determined, as well as the equilibrium physical property parameters of each component in the equilibrium composition.

[0244] By determining the free energy corresponding to each pore in the shale pore system, the equilibrium state parameters of the shale pore system under the condition of minimum total free energy are obtained. Then, the equilibrium components corresponding to the fluid in each pore of the shale pore system, as well as the equilibrium physical property parameters corresponding to each component in the equilibrium components, are determined. This allows the equilibrium physical property parameters to be correlated with the state of each pore, thereby improving the accuracy and effectiveness of the equilibrium physical property parameters and the accuracy of the phase transition characteristics evaluation of the shale fluid system.

[0245] As an optional implementation, the size calculation module 44 calculates the effective pore size of each pore in the shale pore system according to the equilibrium physical property parameters, including:

[0246] Based on the aforementioned equilibrium physical property parameters, determine the adsorption capacity of each pore in the shale pore system;

[0247] The thickness of the adsorption layer corresponding to each pore is determined based on the adsorption amount of each pore.

[0248] The effective pore size of each pore in the shale pore system is determined based on the adsorption layer thickness corresponding to each pore.

[0249] By balancing physical property parameters, the actual adsorption capacity and adsorption layer thickness of each pore in the shale pore system can be determined, thereby obtaining the corresponding effective pore size. This allows for more accurate dew point temperature and / or bubble point temperature, thus improving the accuracy of phase change characteristic evaluation of the shale fluid system.

[0250] As an optional implementation, the temperature determination module 45 determines the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system according to the effective pore size and the initial dew point temperature and / or initial bubble point temperature, including:

[0251] Determine the fluid phase state and initial equilibrium constant corresponding to each fluid component in each pore of the shale pore system;

[0252] Based on the fluid phase state and initial equilibrium constant, determine the mole fraction of each fluid component in each pore;

[0253] Determine the initial capillary force, and based on the initial capillary force and the thickness of the adsorption layer, determine the gas-liquid two-phase density in each pore, and calculate the actual capillary force based on the calculated gas-liquid two-phase density.

[0254] The actual capillary force is used to indicate the intermolecular interaction force and capillary pressure in the corresponding pore.

[0255] Based on the actual capillary force and the thickness of the adsorption layer, the gas-liquid two-phase fugacity of each fluid component in each pore is determined, and the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system is determined based on the gas-liquid two-phase fugacity.

[0256] By determining the actual capillary force of each pore, and then determining the intermolecular interaction force and capillary pressure in the corresponding pore, it can be used to determine the gas-liquid two-phase fugacity of each fluid component in each pore, and calculate the error based on the gas-liquid two-phase fugacity, thereby calculating or updating the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system, thereby improving the accuracy of the phase change characteristic evaluation of the shale fluid system.

[0257] As an optional implementation, please refer to Figure 5 , Figure 5 This is a schematic diagram of another shale fluid phase change characteristic evaluation device disclosed in an embodiment of the present invention. Figure 5 As shown, the device further includes a verification module 47, which is used to determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system after the temperature determination module 45 determines the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size, the initial dew point temperature and / or the initial bubble point temperature, and then determines the mole fraction of each fluid component in each pore based on the fluid composition and fluid phase of each pore in the shale pore system.

[0258] The total mole fraction of each pore is determined based on the mole fraction of each fluid component in each pore.

[0259] Determine whether the total mole fraction of each pore is the first value. If it is determined that the total mole fraction of the pore is not the first value, then based on the determined actual dew point temperature and / or actual bubble point temperature, iteratively update the actual dew point temperature and / or actual bubble point temperature to the initial physical property parameters of the corresponding pore, and trigger the equilibrium parameter determination module 43 to execute the steps of determining the initial dew point temperature and / or initial bubble point temperature, and the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state, based on the initial physical property parameters.

[0260] If the total mole fraction of the pores is determined to be the first value, the phase change characteristic determination module 46 is triggered to perform the step of determining the phase change characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore.

[0261] By determining the mole fraction of the fluid in the pores and further determining the total mole fraction, it is possible to determine whether the conditions indicated by the first numerical value are met, and whether the actual dew point temperature and / or actual bubble point temperature need to be updated. This improves the effectiveness of the dew point temperature and bubble point temperature data, thereby enhancing the accuracy of the phase change characteristics evaluation of shale fluid systems.

[0262] Example 5

[0263] This application provides an electronic device, including:

[0264] At least one processor; and

[0265] A memory communicatively connected to the at least one processor; wherein,

[0266] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method as described in any embodiment.

[0267] This application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any embodiment.

[0268] For details, please refer to Figure 6 , Figure 6 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of the present invention. For example... Figure 6 As shown, the electronic device may include:

[0269] The device includes a processor 291 and a memory 292 storing executable program code; it may also include a communication interface 293 and a bus 294. The processor 291, memory 292, and communication interface 293 can communicate with each other via the bus 294. The communication interface 293 can be used for information transmission. The processor 291 is coupled to the memory 292, and the processor 291 can call logical instructions (executable program code) in the memory 292 to execute the text processing model training method described in any of the above embodiments.

[0270] Furthermore, the logic instructions in the aforementioned memory 292 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0271] The memory 292, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, thereby implementing the methods in the above-described method embodiments.

[0272] The memory 292 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 292 may include high-speed random access memory and may also include non-volatile memory.

[0273] This invention also provides a computer-readable storage medium storing computer-executable instructions, which, when invoked, are used to implement the method described in any of the embodiments.

[0274] This invention also discloses a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a computer to perform the steps in the text processing model training method described in any embodiment.

[0275] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0276] Through the detailed description of the above embodiments, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0277] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0278] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for evaluating the phase transition characteristics of shale fluids, characterized in that, The method includes: The pore size distribution parameters in the shale pore system are obtained, a multi-scale pore model is established based on the pore size distribution parameters, and the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition are obtained based on the multi-scale pore model. Based on the initial physical property parameters, determine the initial dew point temperature and / or initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions. Based on the equilibrium physical property parameters, calculate the effective pore size of each pore in the shale pore system; Based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system; The phase transition characteristics of the shale pore system are determined based on the actual dew point temperature and / or actual bubble point temperature of each pore. The step of determining the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters includes: Based on the composition of the fluid in each pore of the shale pore system and the initial physical property parameters corresponding to each composition, the free energy corresponding to each pore in the shale pore system is determined. Based on the free energy corresponding to each pore in the shale pore system, the total free energy of the shale pore system is determined, and the equilibrium state parameters of the shale pore system are determined based on the total free energy. Based on the equilibrium state parameters, determine the equilibrium composition of the fluid in each pore of the shale pore system, as well as the equilibrium physical property parameters of each component in the equilibrium composition. The step of calculating the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters includes: Based on the aforementioned equilibrium physical property parameters, determine the adsorption capacity of each pore in the shale pore system; The thickness of the adsorption layer corresponding to each pore is determined based on the adsorption amount of each pore. The effective pore size of each pore in the shale pore system is determined based on the adsorption layer thickness corresponding to each pore.

2. The method according to claim 1, characterized in that, The step of determining the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature includes: Determine the fluid phase state and initial equilibrium constant corresponding to each fluid component in each pore of the shale pore system; Based on the fluid phase state and initial equilibrium constant, determine the mole fraction of each fluid component in each pore; Determine the initial capillary force, and based on the initial capillary force and the thickness of the adsorption layer, determine the gas-liquid two-phase density in each pore, and calculate the actual capillary force based on the calculated gas-liquid two-phase density. The actual capillary force is used to indicate the intermolecular interaction force and capillary pressure in the corresponding pore. Based on the actual capillary force and the thickness of the adsorption layer, the gas-liquid two-phase fugacity of each fluid component in each pore is determined, and the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system is determined based on the gas-liquid two-phase fugacity.

3. The method according to claim 1 or 2, characterized in that, After determining the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature, the method further includes: Based on the fluid composition and phase of each pore in the shale pore system, determine the mole fraction of each fluid component in each pore. The total mole fraction of each pore is determined based on the mole fraction of each fluid component in each pore. Determine whether the total mole fraction of each pore is the first value. If it is determined that the total mole fraction of the pore is not the first value, then based on the determined actual dew point temperature and / or actual bubble point temperature, iteratively update the actual dew point temperature and / or actual bubble point temperature to the initial physical property parameters of the corresponding pore, and trigger the execution of the steps of determining the initial dew point temperature and / or initial bubble point temperature, and the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium state based on the initial physical property parameters. If the total mole fraction of the pores is determined to be the first value, then the step of determining the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore is triggered.

4. A device for evaluating the phase transition characteristics of shale fluids, characterized in that, The device includes: The model building module is used to obtain pore size distribution parameters in the shale pore system and to build a multi-scale pore model based on the pore size distribution parameters. An initialization module is used to obtain the composition of the fluid in each pore of the shale pore system, as well as the initial physical property parameters corresponding to each composition, based on the multi-scale pore model. The equilibrium parameter determination module is used to determine the initial dew point temperature and / or initial bubble point temperature, as well as the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions, based on the initial physical property parameters. The size calculation module is used to calculate the effective pore size of each pore in the shale pore system based on the equilibrium physical property parameters. A temperature determination module is used to determine the actual dew point temperature and / or actual bubble point temperature of each pore in the shale pore system based on the effective pore size and the initial dew point temperature and / or initial bubble point temperature. A phase transition characteristic determination module is used to determine the phase transition characteristics of the shale pore system based on the actual dew point temperature and / or actual bubble point temperature of each pore. Specifically, when determining the equilibrium physical property parameters of the fluid in each pore of the shale pore system under equilibrium conditions based on the initial physical property parameters, the equilibrium parameter determination module is used to: determine the free energy corresponding to each pore in the shale pore system based on the composition of the fluid in each pore and the initial physical property parameters corresponding to each composition; determine the total free energy of the shale pore system based on the free energy of each pore; determine the equilibrium state parameters of the shale pore system based on the total free energy; and determine the equilibrium composition of the fluid in each pore of the shale pore system and the equilibrium physical property parameters corresponding to each component in the equilibrium composition based on the equilibrium state parameters. The size calculation module is specifically used to determine the adsorption amount of each pore in the shale pore system based on the equilibrium physical property parameters; to determine the adsorption layer thickness corresponding to each pore based on the adsorption amount of each pore; and to determine the effective pore size of each pore in the shale pore system based on the adsorption layer thickness corresponding to each pore.

5. An electronic device, comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method as described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-3.

Images