Prediction method for carbon dioxide leakage rate of sequestration body based on process flux

Abstract

The invention provides a sequestration body carbon dioxide leakage amount prediction method based on process flux, and relates to the technical field of carbon dioxide oil displacement sequestration technology and environmental safety monitoring and evaluation, and the method comprises the steps: building a geologic model for a target sequestration body, and recognizing a potential initial leakage source of the target sequestration body; setting an initial leakage source for simulation in the geologic model based on the potential initial leakage source, and calculating a theoretical leakage flux of the initial leakage source diffusing through any depth section; according to the theoretical leakage flux, the predicted leakage amount of all the leakage sources within the specific time after leakage occurs is obtained through calculation. According to the method, the leakage amount of carbon dioxide is calculated by obtaining the diffusion area and the leakage flux of a certain depth after carbon dioxide leakage, so that the leakage amount of carbon dioxide passing through the depth section within a period of time after leakage can be predicted; and an effective support is provided for sealing effect evaluation, leakage safety risk prediction and ecological environment risk management of a carbon dioxide flooding sealing project.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide oil recovery storage technology and environmental safety monitoring and evaluation, and in particular to a method for predicting the leakage of carbon dioxide from a storage body based on process flux. Background Art

[0002] Carbon capture, utilization and storage (CCUS) is an indispensable carbon neutral technology. Although geological utilization and storage projects usually select areas with stable geological conditions, large reservoir capacity and good caprock sealing, large-scale and long-term storage may cause leakage in various ways, which not only affects the emission reduction effect of CCUS technology, but also affects ecological and environmental safety. Therefore, it is necessary to scientifically predict the leakage of the storage body to support the emission reduction assessment and ecological and environmental risk management of the project.

[0003] At present, the prediction of CO2 leakage from storage bodies mainly adopts the source prediction method. For example, the research on formation leakage is mainly based on the geological characteristics of the leakage source, simulating and predicting the migration of CO2 in the reservoir, combining the location, size and shape of geological cracks and fissures and various scenario assumptions, and predicting the static leakage under different conditions from the source. However, on the one hand, due to the uncertainty of geological fracture characterization, these prediction methods have huge uncertainties; on the other hand, due to the deep formation depth, it is necessary to use high-cost three-dimensional seismic and other technical means to verify and check the prediction. Under the conditions of long injection time and dynamic changes in injection status in actual operation, it is difficult to afford high-frequency monitoring costs to verify the accuracy of the prediction, resulting in this type of prediction method being difficult to apply to actual projects.

[0004] The source-based prediction method has huge uncertainty and high verification costs. In view of the problems of the prior art, the present invention provides a method for predicting the leakage of carbon dioxide from a storage body based on process flux. Summary of the invention

[0005] In order to overcome the defects of the prior art, the purpose of the present invention is to propose a method for predicting the leakage of carbon dioxide in a storage body based on process flux, in order to predict the leakage of CO2 geological storage bodies and reduce the cost of corresponding actual leakage verification, so as to provide effective support for the storage effect evaluation of CO2 oil recovery storage projects, as well as the leakage safety risk prediction and ecological environmental risk management.

[0006] The present invention provides a method for predicting the leakage of carbon dioxide from a storage body based on process flux, the method comprising:

[0007] Establish a geological model for the target storage body and identify the potential initial leakage source of the target storage body;

[0008] Based on the potential initial leakage source, an initial leakage source for simulation is set in the geological model, and a theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated;

[0009] Based on the theoretical leakage flux, the predicted leakage amount of all leakage sources within a specific time after the leakage occurs is calculated.

[0010] According to one embodiment of the present invention, the geological model is established by the following steps:

[0011] Determine the physical properties of each stratum in the geological model based on the geological data of the storage area where the target storage body is located, and establish a two-dimensional orthogonal grid discrete geological model;

[0012] After determining the initial boundary conditions of the two-dimensional orthogonal grid discrete geological model, calculations are performed to obtain the complete geological model.

[0013] According to one embodiment of the present invention, the potential initial leakage source of the target storage body is identified by the following steps:

[0014] Define the boundary of the target storage body through the analysis of the stratigraphic data of the target storage body;

[0015] The potential initial leakage sources are identified by combining the oil recovery production process and the tightness monitoring of the caprock, wherein the leakage mode and initial leakage rate of each potential initial leakage source are determined.

[0016] According to one embodiment of the present invention, the theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated by the following steps:

[0017] Based on the potential initial leakage source, setting the location of the initial leakage source in the geological model;

[0018] Based on the initial leakage mode and initial leakage rate of each of the initial leakage sources, numerical simulation is performed through the geological model to obtain the distribution of mass fraction within the diffusion range of carbon dioxide within a certain period of time, the dynamic change of formation pressure, and the dynamic analysis results of carbon dioxide plume migration and aggregation;

[0019] According to the numerical simulation results, the migration and diffusion paths of each initial leakage source after leakage are analyzed to determine the leakage and diffusion mode of the initial leakage source;

[0020] The theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated through the breach area, pressure and temperature of the initial leakage source.

[0021] According to one embodiment of the present invention, the theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated by using the breach area, pressure and temperature in the following expression:

[0022]

[0023] Among them, Q G is the gas leakage rate, kg / s; Y is the outflow coefficient, for critical flow, Y = 1; C d is the gas leakage coefficient, which is 1 when the crack shape is circular; A is the crack area, m 2 ; P is pressure, MPa; M is relative molecular mass, the relative molecular mass of CO2 is 0.044 kg / mol; K is the adiabatic index of the gas; R is the gas constant, which is 8.314 J / (mol·K); T G is the temperature, K.

[0024] According to one embodiment of the present invention, the predicted leakage amount of all leakage sources within a specific time after the leakage occurs is calculated by the following steps:

[0025] The depth section through which each initial leakage source diffuses is discretized into a grid, and the leakage flux data within a specific time after the leakage occurs is obtained through numerical simulation, and the leakage flux and time variation curve is plotted;

[0026] Apply the leakage expression of the leakage source, integrate the leakage flux and time variation curve based on the leakage time, and calculate the carbon dioxide leakage of each grid in a certain depth section within a specific time after the leakage occurs;

[0027] Based on the carbon dioxide leakage of each grid, the carbon dioxide leakage of all leakage sources is calculated by using the total leakage expression as the predicted leakage.

[0028] According to one embodiment of the present invention, the leakage amount of the leakage source is expressed as:

[0029]

[0030] The total leakage expression is:

[0031]

[0032] Among them, Q j is the carbon dioxide leakage from leakage source j; f j (t) is the carbon dioxide flux per unit time of leakage source j; T is the specific time after the leakage; Q p is the predicted leakage amount; m is the number of leakage sources.

[0033] According to one embodiment of the present invention, the method further comprises:

[0034] Monitor the carbon dioxide leakage flux at each grid point in the depth section and calculate the actual leakage;

[0035] The actual leakage amount and the predicted leakage amount are compared to obtain a prediction error value.

[0036] According to another aspect of the present invention, a storage medium is provided, which contains a series of instructions for executing the method steps as described in any one of the above.

[0037] According to another aspect of the present invention, there is also provided a device for predicting the leakage of carbon dioxide from a storage body based on process flux, which executes the method described in any one of the above items, and the device comprises:

[0038] A leakage source module, which is used to establish a geological model for a target storage body and identify potential initial leakage sources of the target storage body;

[0039] A theoretical leakage module, which is used to set an initial leakage source for simulation in the geological model based on the potential initial leakage source, and calculate the theoretical leakage flux of the initial leakage source diffusing through any depth section;

[0040] The leakage prediction module is used to calculate the predicted leakage of all leakage sources within a specific time after the leakage occurs based on the theoretical leakage flux.

[0041] The present invention provides a method for predicting the leakage of carbon dioxide from a storage body based on process flux, which has the following advantages over the prior art:

[0042] This method calculates the leakage amount of carbon dioxide by obtaining the diffusion area and leakage flux at a certain depth after the leakage of carbon dioxide, so as to predict the leakage amount of carbon dioxide through the cross section at this depth within a period of time after the leakage, providing effective support for the storage effect evaluation of carbon dioxide flooding and storage projects, as well as the leakage safety risk prediction and ecological environmental risk management.

[0043] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0045] Figure 1A flowchart of a method for predicting leakage of carbon dioxide from a storage body based on process flux according to an embodiment of the present invention is shown;

[0046] Figure 2 A schematic diagram of leakage simulation of a leakage source according to an embodiment of the present invention is shown;

[0047] Figure 3 The graph shows the change of CO2 flux over time at a cross section of 120 meters above the leakage source according to an embodiment of the present invention.

[0048] In the accompanying drawings, the same reference numerals are used for the same components. In addition, the accompanying drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0050] Existing technology (Li Jun, Weng Li, Zhao Xinglei, et al. Study on CO2 leakage prediction at Shenhua Ordos CCS storage site [J]. Chemical Engineering, 2015, 43(11): 11-15.) mentioned: CO2 gas leakage prediction and monitoring is one of the key technologies for CO2 capture and storage. This paper establishes a CO2 leakage diffusion prediction model for the Shenhua Ordos CCS project, studies the CO2 leakage diffusion characteristics and leakage diffusion mode, and uses a CO2 leakage monitor to monitor the CO2 leakage on site. On this basis, the prediction calculation results in this paper are compared and analyzed with the experimental test results to verify the correctness of the prediction method in this paper. Based on this prediction model, the relationship between CO2 leakage and test distance and wind speed is further studied, and the risk under this leakage rate is evaluated based on the current weather conditions. The research results show that: with the increase of downwind distance, the CO2 concentration decreases significantly, and with the increase of the height of the test point from the leakage point, the CO2 concentration decreases relatively slowly. However, the above-mentioned existing technologies only predict near-surface CO2 leakage by combining theoretical deduction and experimental measurement, and do not conduct leakage monitoring and evaluation in other spatial domains.

[0051] The prior art (Li Yuping. A set of empirical formulas for calculating atmospheric diffusion coefficients [J]. Journal of Beijing Institute of Technology, 2009, 29 (10): 914-917.) mentioned: The atmospheric diffusion coefficient data given by D. Bruce Turner were fitted using the Marquardt method, and it was found that the diffusion coefficient in the horizontal direction within the range of 0.01100.00 km can be expressed by a 5-parameter empirical formula; the diffusion coefficient in the vertical direction can also be calculated using a 5-parameter equation, but it needs to be divided into two sections for fitting and calculation. The maximum absolute error between the fitting result and the data in the literature is less than 40m, and the maximum relative error is less than 5%. However, the above prior art only predicts the atmospheric diffusion process based on empirical formulas, and its applicable conditions have great limitations.

[0052] In order to solve the problems of the current prior art, the present invention proposes a method for predicting the leakage of a CO2 geological storage body and a method for verifying the actual leakage. The main technical problems solved include calculating the leakage of CO2 by obtaining the diffusion area and leakage flux at a certain depth of the storage body, thereby predicting the CO2 leakage through the depth section within a period of time after the leakage. The present invention calculates the leakage of carbon dioxide by simulating the change in carbon dioxide concentration at a certain depth, and then predicts the carbon dioxide leakage through the depth section after a period of time. Compared with the above-mentioned prior art, the present invention is based on the combination of theoretical calculation, numerical simulation, and experimental monitoring to obtain a CO2 leakage prediction method in different spatial domains.

[0053] Figure 1 A flowchart of the steps of a method for predicting the leakage of carbon dioxide from a storage body based on process flux according to an embodiment of the present invention is shown.

[0054] like Figure 1 As shown, in step S101, a geological model for a target storage body is established to identify potential initial leakage sources of the target storage body.

[0055] In one embodiment, in step S101 , a geological model is established through steps S1011 - S1012 .

[0056] In step S1011, the physical properties of each stratum in the geological model are determined according to the geological data of the storage area where the target storage body is located, and a two-dimensional orthogonal grid discrete geological model is established. Specifically, the geological model of the storage body area is established using the preset tools (TOUGH2 simulator and its pre- and post-processors PetraSim). The physical properties of each stratum in the model are determined according to the geological data of the storage area, including parameters such as permeability, porosity, and density, and a two-dimensional orthogonal grid discrete geological model is established.

[0057] In step S1012, the boundary initial conditions of the two-dimensional orthogonal grid discrete geological model are determined and then calculated to obtain a complete geological model. Specifically, the boundary initial conditions of the geological model are determined and then calculated to obtain a complete geological model, wherein the geological model can reflect the geological conditions and characteristics of the strata, including permeability anisotropy and groundwater flow.

[0058] In one embodiment, in step S101, the following steps identify potential initial leakage sources of the target storage body: by analyzing the formation data of the target storage body, define the boundary of the target storage body. Combined with the oil recovery production process and the tightness monitoring of the cap rock, identify potential initial leakage sources, wherein the leakage mode and initial leakage rate of each potential initial leakage source are determined. Specifically, by analyzing the formation data, define the boundary of the storage body. Combined with the oil recovery production process and the tightness monitoring of the cap rock, identify potential initial leakage sources, and determine the leakage mode and initial leakage rate of the initial leakage sources.

[0059] like Figure 1 As shown, in step S102, based on the potential initial leakage source, the initial leakage source for simulation is set in the geological model, and the theoretical leakage flux of the initial leakage source diffusing through any depth section is calculated.

[0060] In one embodiment, in step S102 , the theoretical leakage flux of the initial leakage source diffused through a cross section at any depth is calculated through steps S1021 - S1024 .

[0061] In step S1021, based on the potential initial leakage source, the point position of the initial leakage source is set in the geological model. Specifically, according to the position of the potential initial leakage source, the point position of the initial leakage source for simulation in the geological model is selected.

[0062] In step S1022, based on the initial leakage mode and initial leakage rate of each initial leakage source, numerical simulation is performed through the geological model to obtain the distribution of mass fraction within the diffusion range of carbon dioxide within a certain period of time, the dynamic change of formation pressure, and the dynamic analysis results of carbon dioxide plume migration and aggregation. Specifically, based on the initial leakage mode and initial leakage rate of each leakage source, relevant parameters are input into the geological model for numerical simulation to obtain the distribution of mass fraction within the diffusion range of CO2 within a certain period of time, the dynamic change of formation pressure, and the dynamic analysis of CO2 plume migration and aggregation.

[0063] In step S1023, based on the numerical simulation results, the migration and diffusion path of each initial leakage source after leakage is analyzed to determine the leakage diffusion mode of the initial leakage source.

[0064] In step S1024, the theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated based on the breach area, pressure and temperature of the initial leakage source.

[0065] Specifically, in step S1023, the simulation results are analyzed to determine the migration and diffusion path of each initial leakage source after leakage. In step S1024, the depth (horizontal) section through which each initial leakage source diffuses is determined and the theoretical leakage flux of the section is calculated, to provide assistance for subsequent calculations to predict the leakage amount.

[0066] In one embodiment, the theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated by using the breach area, pressure and temperature in the following expression (1):

[0067]

[0068] Among them, Q G is the gas leakage rate, kg / s; Y is the outflow coefficient, for critical flow, Y = 1; C d is the gas leakage coefficient, which is 1 when the crack shape is circular; A is the crack area, m 2 ; P is pressure, MPa; M is relative molecular mass, the relative molecular mass of CO2 is 0.044 kg / mol; K is the adiabatic index of the gas; R is the gas constant, which is 8.314 J / (mol·K); T G is the temperature, K.

[0069] like Figure 1 As shown, in step S103, the predicted leakage amount of all leakage sources within a specific time after the leakage occurs is calculated based on the theoretical leakage flux.

[0070] In one embodiment, in step S103, the predicted leakage amount of all leakage sources within a specific time after the leakage occurs is calculated through steps S1031-S1033.

[0071] In step S1031, the depth section through which each initial leakage source diffuses is discretized into a grid, and the leakage flux data within a specific time after the leakage occurs is obtained through numerical simulation, and a curve of the leakage flux and time variation is drawn. Specifically, the depth section through which each initial leakage source diffuses is discretized into a grid, and the leakage flux data within a specific time from the beginning of the leakage to a certain time in the future is obtained through numerical simulation, and a curve of the leakage flux and time variation is drawn.

[0072] In step S1032, the leakage source leakage expression is applied, and the leakage flux and time variation curve is integrated based on the leakage time to calculate the carbon dioxide leakage of each grid of a certain depth section within a specific time after the leakage occurs. Specifically, the leakage source leakage expression (2) is applied, and the above curve is integrated based on the leakage time to calculate the CO2 leakage of each grid of a certain section within a period of time after the leakage occurs.

[0073] In step S1033, based on the carbon dioxide leakage of each grid, the carbon dioxide leakage of all leakage sources is calculated by the total leakage expression as the predicted leakage. Specifically, the total leakage expression (3) is applied to add and calculate the CO2 leakage of all leakage sources, and finally the predicted leakage is obtained.

[0074] In one embodiment, the leakage amount of the leakage source is expressed as:

[0075]

[0076] In one embodiment, the total leakage expression is:

[0077]

[0078] Among them, Q j is the carbon dioxide leakage from leakage source j; f j (t) is the carbon dioxide flux per unit time of leakage source j; T is the specific time after the leakage; Q p is the predicted leakage amount; m is the number of leakage sources.

[0079] In one embodiment, the present invention further provides a method for verifying the actual leakage, which comprises: monitoring the carbon dioxide leakage flux at each grid point in the depth section, calculating the actual leakage, and comparing the actual leakage with the predicted leakage to obtain a predicted error value.

[0080] In the method for predicting the leakage of a storage body provided by the present invention, the division of the discretized grids of the flux section and the flux averaging of each grid may be slightly different from the continuous flux distribution of the actual leakage situation, which makes the prediction method have certain errors. At the same time, the real-time flux of each grid is obtained based on the diffusion simulation result of the numerical simulation model, and there may also be certain simulation errors. If the cumulative flux of CO2 for a certain period of time after passing through the plane is defined as the actual leakage, the actual leakage can be obtained by monitoring the CO2 flux of each grid point i; the error of the predicted amount can be obtained by comparing the actual leakage and the predicted leakage, which characterizes the effect of the verification, and can further improve the prediction method for the leakage flux of carbon dioxide in a storage body based on process flux provided by the present invention to improve the prediction accuracy.

[0081] In one embodiment, the actual leakage amount is calculated by the following expression:

[0082]

[0083]

[0084] Among them, Q a is the actual leakage; Q i is the CO2 flux at monitoring point i; n is the number of monitoring points; f i (t)dt is the CO2 flux per unit time at monitoring point i, which can be obtained through sampling analysis or instrument monitoring. T is the period of time after the leak.

[0085] This method calculates the leakage amount of carbon dioxide by obtaining the diffusion area and leakage flux at a certain depth after the leakage of carbon dioxide, so as to predict the leakage amount of carbon dioxide through the cross section at this depth within a period of time after the leakage, providing effective support for the storage effect evaluation of carbon dioxide flooding and storage projects, as well as the leakage safety risk prediction and ecological environmental risk management.

[0086] The method for predicting the leakage of carbon dioxide from a storage body based on process flux provided by the present invention can also be used in conjunction with a computer-readable storage medium, which stores a computer program. The computer program is executed to run the method for predicting the leakage of carbon dioxide from a storage body based on process flux.

[0087] A computer program can run computer instructions, which include computer program code. The computer program code may be in source code form, object code form, executable file, or some intermediate form.

[0088] Computer-readable storage media may include: any entity or device that can carry computer program code, recording media, USB flash drives, mobile hard disks, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0089] It should be noted that the content contained in computer-readable storage media can be appropriately increased or decreased based on the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, based on legislation and patent practices, computer-readable storage media do not include electrical carrier signals and telecommunications signals.

[0090] According to another aspect of the present invention, a device for predicting the leakage of carbon dioxide in a storage body based on process flux is provided, which executes a method for predicting the leakage of carbon dioxide in a storage body based on process flux. The device comprises: a leakage source module, a theoretical leakage module, and a predicted leakage module.

[0091] The leakage source module is used to establish a geological model for the target storage body and identify the potential initial leakage source of the target storage body. The theoretical leakage volume module is used to set the initial leakage source for simulation in the geological model based on the potential initial leakage source, and calculate the theoretical leakage flux of the initial leakage source spreading through any depth section. The predicted leakage volume module is used to calculate the predicted leakage volume of all leakage sources within a specific time after the leakage occurs based on the theoretical leakage flux.

[0092] In one embodiment, taking the theoretical geological conditions of a CO2 flooding and storage project in an oil field as an example, based on the leakage scenario hypothesis, the geological model established by TOUGH2 software is used to simulate CO2 leakage, and the process flux method is applied to calculate the predicted leakage amount.

[0093] like Figure 2 As shown, it is assumed that after the leakage, a cross section 120 meters above the leakage source is passed vertically, such as Figure 3 As shown in Figure 1, the TOUGH2 model is used to simulate the change of the flux in the vertical direction through the cross section over time. The predicted leakage within a period of time can be obtained by numerically integrating the CO2 flux change of the cross section with time. The calculation results of the predicted leakage at different times are shown in Table 1.

[0094] Table 1 Calculation results of leakage at 120 meters

[0095]

[0096] In summary, the present invention provides a method for predicting the leakage of carbon dioxide from a storage body based on process flux, which has the following advantages over the prior art:

[0097] This method calculates the leakage amount of carbon dioxide by obtaining the diffusion area and leakage flux at a certain depth after the leakage of carbon dioxide, so as to predict the leakage amount of carbon dioxide through the cross section at this depth within a period of time after the leakage, providing effective support for the storage effect evaluation of carbon dioxide flooding and storage projects, as well as the leakage safety risk prediction and ecological environmental risk management.

[0098] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0099] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0100] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0101] Certain terms are used throughout this application document to indicate specific system components. As those skilled in the art will recognize, different names can usually be used to indicate the same components, so this application document is not intended to distinguish those components that are only different in name but not in function. In this application document, the terms "comprise", "include" and "have" are used in an open form, and therefore should be interpreted as meaning "including but not limited to...". In addition, the terms "substantially", "substantially" or "approximately" that may be used in this article relate to the tolerances of the corresponding terms accepted by the industry. The term "coupling" as may be used in this article includes direct coupling and indirect coupling via other components, elements, circuits, or modules, wherein for indirect coupling, the components, elements, circuits, or modules between them do not change the information of the signal but can adjust its current level, voltage level, and / or power level. Inferred coupling (for example, one of the elements is coupled to another element by inference) includes direct and indirect coupling between two elements in the same way as "coupling".

[0102] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0103] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0104] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for predicting the leakage of carbon dioxide from a storage body based on process flux, characterized in that: The method comprises: Establish a geological model for the target storage body and identify the potential initial leakage source of the target storage body; Based on the potential initial leakage source, an initial leakage source for simulation is set in the geological model, and a theoretical leakage flux of the initial leakage source diffused through a cross section at any depth is calculated; Based on the theoretical leakage flux, the predicted leakage amount of all leakage sources within a specific time after the leakage occurs is calculated.

2. A method for predicting carbon dioxide leakage from a storage body based on process flux according to claim 1, characterized in that: The geological model is established by the following steps: Determine the physical properties of each stratum in the geological model based on the geological data of the storage area where the target storage body is located, and establish a two-dimensional orthogonal grid discrete geological model; After determining the initial boundary conditions of the two-dimensional orthogonal grid discrete geological model, operations are performed to obtain the complete geological model.

3. A method for predicting carbon dioxide leakage from a storage body based on process flux according to claim 1 or 2, characterized in that: Identify the potential initial leakage source of the target containment volume by the following steps: Define the boundary of the target storage body through the analysis of the stratigraphic data of the target storage body; The potential initial leakage sources are identified by combining the oil recovery production process and the tightness monitoring of the caprock, wherein the leakage mode and initial leakage rate of each potential initial leakage source are determined.

4. A method for predicting carbon dioxide leakage in a storage body based on process flux according to any one of claims 1 to 3, characterized in that: The theoretical leakage flux of the initial leakage source diffused through a cross section of any depth is calculated by the following steps: Based on the potential initial leakage source, setting the location of the initial leakage source in the geological model; Based on the initial leakage mode and initial leakage rate of each of the initial leakage sources, numerical simulation is performed through the geological model to obtain the distribution of mass fraction within the diffusion range of carbon dioxide within a certain period of time, the dynamic change of formation pressure, and the dynamic analysis results of carbon dioxide plume migration and aggregation; According to the numerical simulation results, the migration and diffusion paths of each initial leakage source after leakage are analyzed to determine the leakage and diffusion mode of the initial leakage source; The theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated through the breach area, pressure and temperature of the initial leakage source.

5. The method for predicting the leakage of carbon dioxide from a storage body based on process flux according to claim 4, characterized in that: The theoretical leakage flux of the initial leakage source diffusing through a cross section at any depth is calculated by using the breach area, pressure and temperature in the following expression: Among them, Q G is the gas leakage rate, kg / s; Y is the outflow coefficient, for critical flow, Y = 1; C d is the gas leakage coefficient, which is 1 when the crack shape is circular; A is the crack area, m 2 ; P is pressure, MPa; M is relative molecular mass, the relative molecular mass of CO2 is 0.044 kg / mol; K is the adiabatic index of the gas; R is the gas constant, which is 8.314 J / (mol·K); T G is the temperature, K.

6. A method for predicting carbon dioxide leakage in a storage body based on process flux according to any one of claims 1 to 5, characterized in that: The predicted leakage volume of all leakage sources within a specific time after the leakage occurs is calculated by the following steps: The depth section through which each initial leakage source diffuses is discretized into a grid, and the leakage flux data within a specific time after the leakage occurs is obtained through numerical simulation, and the leakage flux and time variation curve is plotted; Apply the leakage expression of the leakage source, integrate the leakage flux and time variation curve based on the leakage time, and calculate the carbon dioxide leakage of each grid in a certain depth section within a specific time after the leakage occurs; Based on the carbon dioxide leakage of each grid, the carbon dioxide leakage of all leakage sources is calculated by using the total leakage expression as the predicted leakage.

7. The method for predicting the leakage of carbon dioxide from a storage body based on process flux according to claim 6, characterized in that: The leakage amount expression of the leakage source is: The total leakage expression is: Among them, Q j is the carbon dioxide leakage from leakage source j; f j (t) is the carbon dioxide flux per unit time of leakage source j; T is the specific time after the leakage; Q p is the predicted leakage amount; m is the number of leakage sources.

8. A method for predicting carbon dioxide leakage in a storage body based on process flux according to any one of claims 1 to 7, characterized in that: The method further comprises: Monitor the carbon dioxide leakage flux at each grid point in the depth section and calculate the actual leakage; The actual leakage amount and the predicted leakage amount are compared to obtain a prediction error value.

9. A storage medium, characterized in that: It contains a series of instructions for executing the method steps as claimed in any one of claims 1-8.

10. A device for predicting the leakage of carbon dioxide from a storage body based on process flux, characterized in that: The method according to any one of claims 1 to 8 is performed, wherein the device comprises: A leakage source module, which is used to establish a geological model for a target storage body and identify potential initial leakage sources of the target storage body; A theoretical leakage module, which is used to set an initial leakage source for simulation in the geological model based on the potential initial leakage source, and calculate the theoretical leakage flux of the initial leakage source diffusing through any depth section; The leakage prediction module is used to calculate the predicted leakage of all leakage sources within a specific time after the leakage occurs based on the theoretical leakage flux.

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