Screening method and terminal for phase-change materials in deep-sea well cementation cement

Abstract

The invention relates to the technical field of machine learning, and discloses a method and terminal for screening phase-change materials in deep-sea well cementation cement, and the method comprises the steps: building a mathematical analysis model of the deep-sea well cementation cement; establishing a data set according to the mathematical analysis model, and establishing an agent model of the mathematical analysis model as a temperature prediction model according to the data set; and screening the phase change material in the deep sea well cementation cement according to the temperature prediction model. According to the method, the mathematical analysis model of deep sea well cementation is established, a large amount of simulation data is acquired according to the result of the data analysis model, so that the data set capable of meeting the requirements of the neural network is established, the neural network is trained based on the data set to establish the agent model, and the agent model is used for rapidly screening the phase-change material. And the complex and changeable construction environment is met.

Description

Technical Field

[0001] The present invention relates to the field of machine learning technology, and in particular to a method, a terminal and a readable storage medium for screening phase change materials in deep-sea cementing cement. Background Art

[0002] Before deep-sea oil and gas exploitation, cement needs to be injected into the gap between the casing and the formation to stabilize the oil well. Cement will release a large amount of hydration heat during the hydration process, causing the system temperature to rise. In the shallow deep sea, there are often hydrate layers. Hydrates are mainly composed of solidified methane and exist stably under high pressure and specific low temperature conditions (usually not higher than 18°C). Once the temperature exceeds its equilibrium temperature boundary value, the hydrate will decompose and release a large amount of gas, which is easy to form a gas channel in the cement ring, affecting the cementing quality. In severe cases, it will cause cementing failure and formation collapse.

[0003] Therefore, temperature control is required. Traditionally, the heat of hydration and maximum temperature are usually adjusted by chemical means of low-activity cement-based materials and inert filler materials, such as fly ash, slag and silica sand. However, reducing the heat of hydration of cement by chemical means usually leads to reduced material strength, especially in the early stages. In addition, in order to control the hydration heat and temperature distribution of cement slurry as much as possible, the amount of fly ash and slag usually accounts for 50-60% of the total amount of cement-based materials, which also leads to higher costs of cement slurry. Moreover, there are large differences between fly ash and slag from different manufacturers and different batches, making it difficult to obtain stable control of temperature.

[0004] In recent years, phase change materials (PCM) have gradually been used to control the hydration heat and temperature rise of building concrete. However, it has also been found that molten phase change materials have a serious impact on the application properties of building concrete, such as mechanical properties and permeability. To this end, the existing technology uses different shell materials to microencapsulate phase change materials to overcome the negative impact of phase change materials on the application performance of cement slurry. Microencapsulated phase change materials (MPCM) have been widely used in the field of building concrete. However, microencapsulated phase change materials are less used in the field of oil well cementing. Research often focuses on verifying the effectiveness of temperature control of phase change materials under hypothetical working conditions, but the deep-sea oil well environment is complex and changeable, and there is a large gap from the ideal working conditions. Therefore, the existing technology cannot meet the complex and changeable engineering requirements of the deep-sea oil well environment. Summary of the invention

[0005] The purpose of the present invention is to provide a method for screening phase change materials in deep-sea cementing cement, aiming to solve the problem that the existing method for selecting phase change materials cannot meet the complex and changeable environment of deep-sea oil wells.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] The present invention provides a method for screening phase change materials in deep-sea cementing cement, and the method for screening phase change materials in deep-sea cementing cement specifically comprises:

[0008] Establish a mathematical analysis model for deep-sea cementing;

[0009] Establishing a data set according to the mathematical analysis model, and establishing a proxy model of the mathematical analysis model according to the data set as a temperature prediction model;

[0010] The phase change material in the deep-sea cementing cement is screened according to the temperature prediction model.

[0011] Furthermore, the establishment of a mathematical analysis model for deep-sea cementing specifically includes:

[0012] Establishing a thermal conduction model of the deep-sea cement and a thermal conduction model of the formation;

[0013] Establishing a heat release model during the cement hydration process of the deep-sea cementing cement;

[0014] A mathematical analysis model with a temperature peak as output is established based on the heat conduction model and the heat release model.

[0015] Furthermore, the establishment of the thermal conduction model of the deep-sea cement and the thermal conduction model of the formation specifically includes:

[0016] Establishing the specific heat model of deep sea cementing cement:

[0017] ρ eff c p,eff (T) = φ c ρ c c p,c (T)+φ s ρ s c p,s +(1-φ c -φ s )ρ m c p,m ;

[0018] Among them, T is the independent variable temperature, ρ represents density, c p,eff (T) represents the specific heat of cement containing phase change material, ρ eff represents the density of cement containing phase change materials, φ c represents the volume fraction of the core, ρ c represents the density of the nucleus, c p,c (T) represents the specific heat of the core, φ s represents the volume fraction of the shell, ρs represents the density of the shell, c p,s represents the specific heat of the shell, ρ m represents the density of cement matrix, c p,m represents the specific heat of cement matrix;

[0019] Among them, the specific heat of the core c p,c (T) is:

[0020]

[0021] Among them, T melting is the melting temperature of the phase change material, h sf is the latent heat of fusion, ΔT melting is the melting temperature window, c p,c,s is the solid-state relative heat of the phase change material, c p,c,l Liquid phase heat of phase change material;

[0022] Establishing the thermal conductivity model of deep-sea cementing cement:

[0023]

[0024] Among them, k eff represents the effective thermal conductivity of cement containing phase change materials, k m represents the thermal conductivity of the cement matrix, k c represents the thermal conductivity of the core of the phase change material, k s represents the thermal conductivity of the shell of the phase change material;

[0025] A thermal conduction model of deep-sea cementing cement is established based on the specific heat model and the thermal conductivity model:

[0026]

[0027] in, It represents the heat generation rate of cement per unit volume at position r at time t, in units of (w / m 3 ), c p,eff (T) represents the relationship between the effective specific heat in the cement sheath and the temperature;

[0028] Establish a heat conduction model for the formation:

[0029]

[0030] Where r represents the position r away from the center of the cement ring, ρ h represents the formation density, c p,h represents the formation specific heat, T h represents the formation temperature, k h Represents the thermal conductivity of the formation.

[0031] Furthermore, the heat release model of the deep-sea cementing cement during hydration is established, specifically including:

[0032] Establish the equivalent age model of cement hydration process:

[0033]

[0034] Where t represents time, E a represents the activation energy of hydration reaction, R represents the ideal gas constant, T ref represents the reference temperature, t eq (r,t) represents the equivalent age t eq The function of changing with time t and position r, T(r,t) represents the function of temperature T changing with time t and position r;

[0035] The hydration degree model was established based on the equivalent age model:

[0036]

[0037] Among them, θ ∞ , B, τ are experimentally measured hydration curve parameters, θ(t eq ) represents the equivalent age t eq Degree of hydration at ;

[0038] According to the hydration degree model, a total heat model released per unit volume during the hydration process is established:

[0039] Q(t eq )=C c ΔHθ(t eq );

[0040] Among them, Q(t eq ) indicates that cement hydration develops to t eq The total heat released per unit volume at the age, C c is the cement content per unit volume, ΔH is the reaction enthalpy of cement hydration;

[0041] The heat generation rate model of cement per unit volume is established according to the total heat model:

[0042]

[0043] in, It represents the heat generation rate per unit volume of cement at position r at time t.

[0044] Furthermore, the screening of the phase change material in the deep-sea cementing cement according to the temperature prediction model specifically includes:

[0045] Acquire temperature peak values ​​corresponding to a plurality of phase change materials according to the temperature prediction model;

[0046] Obtain the hydrate hydrolysis temperature of the formation where deep-sea cementing is located;

[0047] The phase change materials are screened according to the hydrate hydrolysis temperature and the temperature peak value corresponding to each phase change material.

[0048] Furthermore, obtaining the temperature peak values ​​corresponding to the plurality of phase change materials according to the temperature prediction model specifically includes:

[0049] Acquire the cementing initial temperature, hydrate saturation and formation porosity, as well as the phase change material melting temperature, phase change material volume fraction and phase change material latent heat of each phase change material, and input the cementing initial temperature, the hydrate saturation and the formation porosity, as well as the phase change material melting temperature, the phase change material volume fraction and the phase change material latent heat of each phase change material into the temperature prediction model;

[0050] The temperature prediction model outputs the peak temperature of each phase change material.

[0051] Furthermore, the obtaining of the hydrate hydrolysis temperature of the formation where the deep-sea cementing is located specifically includes:

[0052] Acquiring a hydrate three-phase equilibrium model, formation temperature, hydrate saturation and formation porosity, and inputting the formation temperature, the hydrate saturation and the formation porosity into the hydrate three-phase equilibrium model;

[0053] The hydrate three-phase equilibrium model outputs the hydrate hydrolysis temperature.

[0054] Furthermore, the screening of each phase change material according to the hydrate hydrolysis temperature and the temperature peak value corresponding to each phase change material specifically includes:

[0055] For each phase change material in turn, determining whether the corresponding temperature peak is less than the hydrate hydrolysis temperature;

[0056] If the temperature peak is less than the hydrate hydrolysis temperature, the corresponding phase change material is retained;

[0057] If the temperature peak is not less than the hydrate hydrolysis temperature, the corresponding phase change material is filtered out.

[0058] In addition, to achieve the above-mentioned purpose, the present invention also provides a terminal, which includes: a memory, a processor, and a phase change material screening program in deep-sea cementing cement stored in the memory and executable on the processor, wherein the phase change material screening program in deep-sea cementing cement controls the terminal to implement the steps of the phase change material screening method in deep-sea cementing cement as described above when the phase change material screening program in deep-sea cementing cement is executed by the processor.

[0059] In addition, to achieve the above-mentioned purpose, the present invention also provides a readable storage medium, which stores a phase change material screening program in deep-sea cementing cement. When the phase change material screening program in deep-sea cementing cement is executed by a processor, the steps of the phase change material screening method in deep-sea cementing cement as described above are implemented.

[0060] The present invention adopts the above technical solution to achieve the following effects:

[0061] The present invention establishes a mathematical analysis model of deep-sea cementing, and obtains a large amount of simulation data based on the results of the data analysis model, thereby establishing a data set that can meet the needs of the neural network, and trains the neural network based on the data set to establish a proxy model, so as to use the proxy model to achieve rapid screening of phase change materials to meet the complex and changeable construction environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 This is a flow chart of the steps of a method for screening phase change materials in deep-sea cementing cement in a preferred embodiment of the present invention;

[0063] Figure 2 is a schematic diagram of a model of deep-sea cementing in a preferred embodiment of the present invention;

[0064] Figure 3 Schematic diagram of the distribution of the maximum radial temperature in a preferred embodiment of the present invention;

[0065] Figure 4 is a schematic diagram of a sample space in a preferred embodiment of the present invention;

[0066] Figure 5 A schematic diagram of the structure of a temperature prediction model in a preferred embodiment of the present invention;

[0067] Figure 6 A schematic diagram of the training and testing results of the temperature prediction model in a preferred embodiment of the present invention;

[0068] Figure 7 Schematic diagram of the generalization test results of the temperature prediction model in the preferred embodiment of the present invention;

[0069] Figure 8 A weight diagram of additive factor analysis in a preferred embodiment of the present invention;

[0070] Fig. 9 Schematic diagram of sample distribution of additive factorial analysis in a preferred embodiment of the present invention;

[0071] Fig.10 Schematic diagram of the screening process of phase change materials in a preferred embodiment of the present invention;

[0072] Fig.11Schematic diagram of the screening results of the first sea area in a preferred embodiment of the present invention;

[0073] Fig.12 Schematic diagram of the screening results of the second sea area in a preferred embodiment of the present invention;

[0074] Fig.13 A schematic diagram of an operating environment of a preferred embodiment of a terminal of the present invention. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0076] Embodiment 1

[0077] See also Figure 1 Embodiment 1 of the present application is a method for screening phase change materials in deep-sea cementing cement, which comprises the steps of:

[0078] S1. Establish a mathematical analysis model for deep-sea cementing.

[0079] In this embodiment, a finite element analysis model of deep-sea cementing is specifically established. Since the temperature gradient in the well depth direction is significantly smaller than the temperature gradient in the radial direction, the heat conduction in the well depth direction can be ignored, and only the heat conduction in the radial direction is considered.

[0080] First, a heat conduction model for deep-sea cementing needs to be established. Please refer to Figure 2 , Figure 2 This is a schematic diagram of deep-sea cementing heat transfer. The inside of the cylinder is drilling fluid, and the steel casing, cement ring, and hydrate layer are arranged radially outward. The phase change material capsules are randomly distributed in the cement ring. According to previous studies, the effective specific heat of the composite material can be written as the weighted average of each component, that is, the effective specific heat of cement containing phase change material can be written as the weighted average of the specific heat of the core of the phase change material, the specific heat of the shell of the phase change material, and the specific heat of the cement matrix:

[0081] ρ eff c p,eff (T) = φ c ρ c c p,c (T)+φ s ρ s c p,s +(1-φ c -φ s )ρ m c p,m ;

[0082] Among them, T is the independent variable temperature, ρ represents density, cp,eff represents the specific heat of cement containing phase change material, ρ eff represents the density of cement containing phase change materials, c p,eff (T) represents the effective specific heat of cement containing phase change material as a function of temperature, φ c represents the volume fraction of the core, ρ c represents the density of the nucleus, c p,c is the specific heat of the nucleus, c p,c (T) represents the function of the specific heat of the core changing with temperature, φ s represents the volume fraction of the shell, ρ s represents the density of the shell, c p,s represents the specific heat of the shell, ρ m represents the density of cement matrix, c p,m Represents the specific heat of the cement matrix.

[0083] Among them, the specific heat of the core of the phase change material c p,c (T) can be described as:

[0084]

[0085] Among them, T melting is the melting temperature of the phase change material, h sf is the latent heat of fusion, ΔT melting is the melting temperature window, c p,c,s is the solid-state relative heat of the phase change material, c p,c,l is the phase change material liquid phase heat. According to the effective medium theory, the effective thermal conductivity of cement containing phase change material can be calculated using Felske's model:

[0086]

[0087] Among them, k eff represents the effective thermal conductivity of the composite material, i.e. cement containing phase change material, k m represents the thermal conductivity of the cement matrix, k c represents the thermal conductivity of the core of the phase change material, k s represents the thermal conductivity of the shell of the phase change material.

[0088] The one-dimensional heat conduction equation in the cement sheath is:

[0089]

[0090] in, It represents the heat generation rate of cement per unit volume at position r at time t, in units of (w / m 3 ), c p,eff (T) represents the relationship between the effective specific heat inside the cement sheath and the temperature.

[0091] The one-dimensional heat conduction equation in the formation is:

[0092]

[0093] Among them, ρ h represents the formation density, c p,h represents the formation specific heat, T h represents the formation temperature, k h Represents the thermal conductivity of the formation.

[0094] Set the initial conditions to:

[0095] T(r,0)=T h (r,0)=T init ;

[0096] Where T(r,0) represents the temperature inside the cement ring at a distance r from the center of the circle at the initial time, T h (r,0) represents the formation temperature at the initial time, r from the center of the circle, T init represents the initial temperature, the initial temperature T init The geothermal gradient dT melting and the depth h of the stratum:

[0097] T init =dT melting *h;

[0098] Afterwards, the boundary conditions of the model were set. The upper and lower interfaces of the stratum were considered to be thermally insulated, an infinite element domain was set at the outermost interface along the radial direction, the geometric stretching was 10,000 times, and the innermost side was still water natural convection.

[0099] Then, the heat release model of cement hydration process is established. The hydration process of cement is very dependent on temperature. The equivalent age model can well measure the hydration degree of cement. The equivalent age of cement t eq for:

[0100]

[0101] Among them, r represents the position variable in the cement, which is a one-dimensional heat conduction position variable, which is the position r away from the center of the cement ring, t is the time variable, and the equivalent age t eq Both temperature T and position x are functions of time t. T(r,t) represents the function of temperature T changing with time and position. eq (r,t) represents the equivalent age t eq As a function of time and position, E a represents the activation energy of hydration reaction, R = 8.314 J / mol·K is the ideal gas constant, T ref =20℃ is the reference temperature of the laboratory.

[0102] The degree of hydration θ can be approximated as a function of the equivalent age:

[0103]

[0104] Among them, θ(t eq ) represents the equivalent age t eq The degree of hydration at ∞ , B, τ are experimentally measured hydration curve parameters.

[0105] The total heat Q released per unit volume of cement during hydration is a function of the equivalent age:

[0106] Q(t eq )=C c ΔHθ(t eq );

[0107] Among them, Q(t eq ) indicates that cement hydration develops to t eq The total heat released per unit volume at the age, C c is the cement content per unit volume, ΔH is the reaction enthalpy of cement hydration, 475 kJ / kg.

[0108] The heat generation rate of cement per unit volume can be considered as the derivative of the total heat released per unit volume of cement with respect to time:

[0109]

[0110] Among them, E a is the activation energy of hydration reaction, and R = 8.314 J / mol·K is the ideal gas constant.

[0111] S2. Establish a data set according to the mathematical analysis model, and establish a proxy model of the mathematical analysis model according to the data set as a temperature prediction model.

[0112] After establishing the heat transfer model and heat release model, finite element analysis can be performed. The results of the analysis are as follows: Figure 3 As shown in the figure, it can be seen that as the cement hydration reaction proceeds, the temperature peak will appear before 50 hours. Its value decreases as the distance between the observation point and the cement sheath increases. Therefore, the observation point close to the cement sheath is a cementing danger point. Controlling the temperature rise at this point can ensure the safety of the cementing process. In this study, the peak temperature of this point is taken as the research object, and whether the peak temperature of this point exceeds the decomposition temperature of the formation hydrate is used to judge whether the selected phase change material can ensure the safety of the cementing process.

[0113] In addition, according to the analysis results of finite element calculation, there are 6 key parameters (characteristics) that affect the cementing process: melting temperature of phase change material, volume fraction of phase change material, latent heat of phase change material, initial cementing temperature, hydrate saturation, and porosity. Please refer to Figure 4 , Figure 4 The arrow in the middle indicates the feature direction, and the scale on the arrow indicates the uniform value in that direction. The area in {} indicates the value range of the feature, and the area surrounded by the hexagon is the sample space, which contains 11,520 sets of samples. Applying these samples to the finite element heat transfer model can obtain the corresponding peak temperatures (labels) of these samples and obtain a temperature prediction database.

[0114] That is, in this embodiment, 11520 sets of data sets with phase change material melting temperature, phase change material volume fraction, phase change material latent heat, cementing initial temperature, hydrate saturation and formation porosity as samples and peak temperature as label are established to train the neural network to establish a proxy model of finite element analysis as a temperature prediction model.

[0115] In this embodiment, please refer to Figure 5 , the FNN (Forward Neural Net) model is used as the temperature prediction model, which consists of 5 hidden layers, each of which contains 10 neurons trained after hyperparameter adjustment. This model can be used to construct a mapping from sample space to temperature peak:

[0116]

[0117] Among them, NN represents the neural network, s is the parameter of the input sample space, θ is the weight of the model, Represents the peak temperature output by the model.

[0118] The training process of the model is the process of optimizing the weights:

[0119]

[0120] T peak is the true value calculated by the finite element model, θ * Represents the weight of the optimal model obtained through training.

[0121] The training results of the model are as follows Figure 6 As shown in the figure, during the training process, the model shows uniform convergence properties on the training set and the validation set, proving that the model is not overfitting. On the test set, R 2 =0.995, which proves that the prediction error of the model is very low. By resampling, taking new eigenvalues ​​inside and outside the sample space for finite element calculation, 2700 sets of interpolated data sets and 1440 sets of expanded data sets were obtained. Figure 7As shown in the figure, the model performs very well on these two datasets, proving that the model can also make good predictions for situations that have never occurred before, indicating that it has good generalization and can be deployed for use.

[0122] In this embodiment, after the training is completed, Shapley game theory-based additive explanations are used to explain how the neural network processes data, making the model's predictions more reliable and secure.

[0123] The average result of the additive factor analysis is the Shapley value. Figure 8 As shown, Figure 8 It describes the average impact of different features on the results in the data set. Figure 8 In the figure, temp_place is the initial temperature, phi_sc is the volume fraction of the phase change material, poro is the formation porosity, phi_h is the hydrate saturation, PCM_melting is the melting temperature of the phase change material, and hsf is the latent heat of the phase change material. From the analysis of the Shapley average value, we can conclude that these parameters that need to be considered are important for temperature control. It can be seen that the initial temperature temp_place has the greatest impact on the peak temperature, that is, the deeper the formation, the greater the geothermal gradient, and the higher the peak temperature of the cementing process.

[0124] Please refer to Fig. 9 , Fig. 9 is the scatter distribution of the Shapley values ​​of all samples, the horizontal axis is the Shapley value, and the vertical axis is the order of the features. Fig. 9 and Figure 8 The order in corresponds to . Positive Shapley values ​​represent promotion results, and negative values ​​represent inhibition results. Each row represents the scatter distribution of a feature. The more scatter points with the same Shapley value, the wider the band presented. Since the samples are not randomly sampled, there are many strips with concentrated scatter points. The color of the scatter points changes from red to blue, indicating that the value of the feature changes from large to small. It can be seen that the increase in initial temperature will promote the increase in the cementing temperature peak, and the larger the volume fraction of the phase change material, the smaller the cementing temperature peak will be, and the volume fraction of the phase change material will not promote the cementing temperature peak. It can be seen that the rules learned by deep learning revealed by Shapley game theory are intuitive and understandable.

[0125] S3. Screening the phase change material in the deep-sea cementing cement according to the temperature prediction model.

[0126] Please refer to Fig.10 , Fig.10This is a flow chart for phase change material screening. By deploying the temperature prediction model into the screening program, phase change materials can be quickly screened. During the screening process, the collected phase change material property table will be traversed to find the corresponding material name and its thermophysical properties (melting temperature, latent heat of melting), and then a volume fraction will be given. For the formation you want to study, you need to enter the formation temperature, hydrate saturation, and formation porosity. The program will use these parameters to calculate the maximum temperature of the cementing process through the temperature prediction model. On the other hand, enter the seawater depth, formation depth, and formation thickness of the formation. The program will calculate the hydrolysis temperature of the hydrate in the formation based on the three-phase equilibrium conditions of the hydrate. Finally, the program determines whether to store the serial number of the material and the volume fraction to be used by judging whether the maximum temperature exceeds the hydrate hydrolysis temperature. In this process, a step-by-step method will be taken to find the minimum usage volume fraction of the material.

[0127] Please refer to Fig.11 and Fig.12 , Fig.11 and Fig.12 The phase change material screening results of the two sea areas were recorded respectively. Fig.11 Record the screening results of the first sea area, Fig.12 Record the screening results of the second sea area. Fig.11 This is the screening result of the screening program for the first sea area natural gas production site. The figure records the phase change materials and their volume fractions screened out for the formation conditions of the site, as well as the melting temperature corresponding to the material. Since a large number of materials were screened out, the horizontal axis cannot record all the serial numbers, so the serial numbers are omitted. Fig.12 The following is the screening result of the second offshore mining site using this screening procedure. The screened materials and their usage can be used as a reference in actual engineering.

[0128] Embodiment 2

[0129] See also Fig.13 Based on the above method, the present invention further provides a terminal, which includes a processor 10, a memory 20 and a display 30. However, it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead.

[0130] In some embodiments, the memory 20 may be an internal storage unit of the terminal, such as a hard disk or memory of the terminal. In other embodiments, the memory 20 may also be an external storage device of the terminal, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the terminal. Further, the memory 20 may also include both an internal storage unit of the terminal and an external storage device. The memory 20 is used to store application software and various types of data installed on the terminal, such as the program code of the installation terminal. The memory 20 may also be used to temporarily store data that has been output or is to be output. In one embodiment, a phase change material screening program 40 in deep-sea cementing cement is stored in the memory 20, and the phase change material screening program 40 in deep-sea cementing cement can be executed by the processor 10, thereby realizing the terminal in the present application.

[0131] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor or other data processing chip, used to run the program code or process data stored in the memory 20, such as executing related programs of the method for screening phase change materials in deep-sea cementing cement.

[0132] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an OLED (Organic Light Emitting Diode) touch device, etc. The display 30 is used to display information on the terminal and to display a visual user interface.

[0133] In one embodiment, when the processor 10 executes the phase change material screening program 40 in the memory 20, the steps of the method for screening phase change materials in deep-sea cementing cement as described above are implemented.

[0134] Embodiment 3

[0135] This embodiment provides a storage medium, wherein the readable storage medium stores a program for screening phase change materials in deep-sea cementing cement, and when the program for screening phase change materials in deep-sea cementing cement is executed by a processor, the steps of a method for screening phase change materials in deep-sea cementing cement as described above are implemented.

[0136] In summary, the present invention establishes a mathematical analysis model of deep-sea cementing, and obtains a large amount of simulation data based on the results of the data analysis model, thereby establishing a data set that can meet the needs of the neural network, and trains the neural network based on the data set to establish a proxy model, so as to use the proxy model to realize the rapid screening of phase change materials to meet the complex and changeable construction environment.

[0137] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal 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 terminal. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or terminal including the element.

[0138] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the program can be stored in a computer-readable storage medium, and the program can include the processes of the above-mentioned method embodiments when executed. The storage medium can be a memory, a disk, an optical disk, etc.

[0139] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for screening phase change materials in deep-sea cementing cement, characterized in that: The method for screening phase change materials in deep-sea cementing cement specifically comprises: Establish a mathematical analysis model for deep-sea cementing; Establishing a data set according to the mathematical analysis model, and establishing a proxy model of the mathematical analysis model according to the data set as a temperature prediction model; The phase change material in the deep-sea cementing cement is screened according to the temperature prediction model.

2. A method for screening phase change materials in deep sea cementing cement according to claim 1, characterized in that: The mathematical analysis model of deep-sea cementing is established, specifically including: Establishing a thermal conduction model of the deep-sea cement and a thermal conduction model of the formation; Establishing a heat release model during the cement hydration process of the deep-sea cementing cement; A mathematical analysis model with a temperature peak as output is established based on the heat conduction model and the heat release model.

3. A method for screening phase change materials in deep sea cementing cement according to claim 2, characterized in that: The step of establishing the thermal conduction model of the deep-sea cement and the thermal conduction model of the formation specifically includes: Establishing the specific heat model of deep sea cementing cement: r eff c p,eff (T)=φ c r c c p,c (T)+φ s r s c p,s +(1-φ c -f s )r m c p,m ; Among them, T is the independent variable temperature, ρ represents density, c p,eff (T) represents the specific heat of cement containing phase change material, ρ eff represents the density of cement containing phase change materials, φ c represents the volume fraction of the core, ρ c represents the density of the nucleus, c p,c (T) represents the specific heat of the core, φ s represents the volume fraction of the shell, ρ s represents the density of the shell, c p,s represents the specific heat of the shell, ρ m represents the density of cement matrix, c p,m represents the specific heat of cement matrix; Among them, the specific heat of the core c p,c (T) is: Among them, T melting is the melting temperature of the phase change material, h sf is the latent heat of fusion, ΔT melting is the melting temperature window, c p,c,s is the solid-state relative heat of the phase change material, c p,c,l Liquid phase heat of phase change material; Establishing the thermal conductivity model of deep-sea cementing cement: Among them, k eff represents the effective thermal conductivity of cement containing phase change materials, k m represents the thermal conductivity of the cement matrix, k c represents the thermal conductivity of the core of the phase change material, k s represents the thermal conductivity of the shell of the phase change material; A thermal conduction model of deep-sea cementing cement is established based on the specific heat model and the thermal conductivity model: in, It represents the heat generation rate of cement per unit volume at position r at time t, in units of (w / m 3 ), c p,eff (t) represents the relationship between the effective specific heat in the cement sheath and the temperature; Establish a heat conduction model for the formation: Where r represents the position r away from the center of the cement ring, ρ h represents the formation density, c p,h represents the formation specific heat, T h represents the formation temperature, k h Represents the thermal conductivity of the formation.

4. A method for screening phase change materials in deep sea cementing cement according to claim 3, characterized in that: The establishment of the heat release model during the cement hydration process of the deep-sea cementing cement specifically includes: Establish the equivalent age model of cement hydration process: Where t represents time, E a represents the activation energy of hydration reaction, R represents the ideal gas constant, T ref represents the reference temperature, t eq (r,t) represents the equivalent age t eq The function of changing with time t and position r, T(r,t) represents the function of temperature T changing with time t and position r; The hydration degree model was established based on the equivalent age model: Among them, θ ∞ , B, τ are experimentally measured hydration curve parameters, θ(t eq ) represents the equivalent age t eq Degree of hydration at ; According to the hydration degree model, a total heat model released per unit volume during the hydration process is established: Q(t eq )=C c ΔHθ(t eq ); Among them, Q(t eq ) indicates that cement hydration develops to t eq The total heat released per unit volume at the age, C c is the cement content per unit volume, ΔH is the reaction enthalpy of cement hydration; The heat generation rate model of cement per unit volume is established according to the total heat model:

5. The method for screening phase change materials in deep sea cementing cement according to claim 1, characterized in that: The screening of the phase change material in the deep-sea cementing cement according to the temperature prediction model specifically includes: Acquire temperature peak values ​​corresponding to a plurality of phase change materials according to the temperature prediction model; Obtain the hydrate hydrolysis temperature of the formation where deep-sea cementing is located; The phase change materials are screened according to the hydrate hydrolysis temperature and the temperature peak value corresponding to each phase change material.

6. A method for screening phase change materials in deep sea cementing cement according to claim 5, characterized in that: The step of obtaining temperature peak values ​​corresponding to a plurality of phase change materials according to the temperature prediction model specifically includes: Acquire the cementing initial temperature, hydrate saturation and formation porosity, as well as the phase change material melting temperature, phase change material volume fraction and phase change material latent heat of each phase change material, and input the cementing initial temperature, the hydrate saturation and the formation porosity, as well as the phase change material melting temperature, the phase change material volume fraction and the phase change material latent heat of each phase change material into the temperature prediction model; The temperature prediction model outputs the peak temperature of each phase change material.

7. A method for screening phase change materials in deep sea cementing cement according to claim 5, characterized in that: The step of obtaining the hydrate hydrolysis temperature of the formation where the deep-sea cementing is located specifically includes: Acquiring a hydrate three-phase equilibrium model, formation temperature, hydrate saturation and formation porosity, and inputting the formation temperature, the hydrate saturation and the formation porosity into the hydrate three-phase equilibrium model; The hydrate three-phase equilibrium model outputs the hydrate hydrolysis temperature.

8. The method for screening phase change materials in deep sea cementing cement according to claim 5, characterized in that: The step of screening each phase change material according to the hydrate hydrolysis temperature and the temperature peak value corresponding to each phase change material specifically includes: For each phase change material in turn, determining whether the corresponding temperature peak is less than the hydrate hydrolysis temperature; If the temperature peak is less than the hydrate hydrolysis temperature, the corresponding phase change material is retained; If the temperature peak is not less than the hydrate hydrolysis temperature, the corresponding phase change material is filtered out.

9. A terminal, characterized in that: The terminal includes: a memory, a processor, and a phase change material screening program in deep-sea cementing cement stored in the memory and executable on the processor. When the phase change material screening program in deep-sea cementing cement is executed by the processor, the terminal is controlled to implement the steps of a method for screening phase change materials in deep-sea cementing cement as described in any one of claims 1-8.

10. A readable storage medium, characterized in that: The readable storage medium stores a phase change material screening program in deep-sea cementing cement, and when the phase change material screening program in deep-sea cementing cement is executed by the processor, the steps of a phase change material screening method in deep-sea cementing cement as described in any one of claims 1-8 are implemented.

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