Method and device for dynamically adjusting carbon dioxide replacement rate of natural gas hydrate reservoir

Abstract

The invention relates to the technical field of natural gas extraction, in particular to a natural gas hydrate reservoir carbon dioxide replacement rate dynamic adjustment method and device, which can dynamically adjust the injection parameters of carbon dioxide, respond to the change of underground environment in time and optimize the replacement process based on real-time data. The method comprises the steps that corresponding initial carbon dioxide injection parameters are set for each carbon dioxide injection well, carbon dioxide injection operation is executed accordingly, and the methane replacement process is started; in the replacement process, collecting replacement characteristic parameters of the target replacement sub-region at a preset monitoring time interval; calculating a fluctuation ratio between adjacent permutation characteristic parameters on a time sequence; according to a preset weight corresponding to each replacement characteristic parameter, performing comprehensive calculation on each fluctuation ratio to obtain a replacement characteristic fluctuation coefficient in a corresponding time interval; and based on a preset permutation characteristic fluctuation threshold, in a preset time window, counting the overstandard rate of the plurality of permutation characteristic fluctuation coefficients.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas exploitation, and particularly to a method and device for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir. Background Art

[0002] In the exploitation and utilization of natural gas hydrates (commonly known as combustible ice), due to their special reservoir structures and physical and chemical properties, traditional exploitation methods often face problems such as low efficiency, high cost, and large environmental impacts. Among them, the carbon dioxide replacement exploitation technology, as an innovative method, injects carbon dioxide into the natural gas hydrate reservoir, and uses the competitive adsorption and dissolution of carbon dioxide and methane in the reservoir to promote the release of methane from the hydrate, thereby achieving the efficient exploitation of methane and simultaneously realizing the geological sequestration of carbon dioxide, which is of great significance for alleviating greenhouse gas emissions and promoting the sustainable utilization of energy. However, in the process of implementing carbon dioxide replacement exploitation, how to precisely control the injection parameters of carbon dioxide to optimize the replacement efficiency of methane and ensure reservoir stability is a major challenge currently faced.

[0003] Existing replacement operations usually rely on fixed carbon dioxide injection parameters, lack real-time monitoring and dynamic adjustment mechanisms, cannot respond in a timely manner to changes in the underground environment, and are difficult to capture changes in reservoir conditions in real time; when reservoir conditions change, corresponding parameter adjustments cannot be made in a timely manner, resulting in poor replacement effects.

[0004] Therefore, there is an urgent need to provide a method and device for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir to solve the above technical problems. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a method and device for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir, which can dynamically adjust the injection parameters of carbon dioxide based on real-time data, respond in a timely manner to changes in the underground environment, and optimize the replacement process.

[0006] In a first aspect, the present invention provides a method for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir, the method comprising:

[0007] Setting corresponding initial carbon dioxide injection parameters for each carbon dioxide injection well, and performing carbon dioxide injection operations therewith to initiate the replacement process of methane;

[0008] During the replacement process, collecting replacement characteristic parameters of a target replacement sub-region at a preset monitoring time interval;

[0009] Calculating the volatility between adjacent replacement characteristic parameters in time series;

[0010] Based on the preset weights corresponding to each permutation characteristic parameter, comprehensively calculate each volatility to obtain the permutation characteristic volatility coefficient within the corresponding time interval;

[0011] Based on the preset permutation characteristic volatility threshold, within the preset time window, count the exceedance rate of multiple permutation characteristic volatility coefficients;

[0012] According to the exceedance rate, dynamically adjust the carbon dioxide injection parameters of the corresponding carbon dioxide injection well.

[0013] On the other hand, the present application also provides a device for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir. The device includes:

[0014] A parameter setting module, configured to set the corresponding initial carbon dioxide injection parameters for each carbon dioxide injection well and start the replacement process of methane;

[0015] A real-time monitoring module, configured to collect the permutation characteristic parameters of the target replacement sub-region at a preset time interval during the replacement process;

[0016] A volatility calculation unit, configured to calculate the volatility between adjacent permutation characteristic parameters in time series according to the data obtained by the real-time monitoring module;

[0017] A fluctuation coefficient calculation unit, configured to comprehensively calculate each volatility according to the preset weights corresponding to each permutation characteristic parameter, so as to obtain the permutation characteristic fluctuation coefficient within the corresponding time interval;

[0018] An exceedance rate statistics module, configured to count the exceedance rate of multiple permutation characteristic fluctuation coefficients within the preset time window based on the preset permutation characteristic volatility threshold;

[0019] An injection parameter dynamic adjustment module, configured to dynamically adjust the carbon dioxide injection parameters of the corresponding carbon dioxide injection well according to the exceedance rate.

[0020] In a third aspect, the present application provides an electronic device, including a bus, a transceiver, a memory, a processor, and a computer program stored on the memory and executable on the processor. The transceiver, the memory, and the processor are connected through the bus, and when the computer program is executed by the processor, the steps in any one of the above methods are implemented.

[0021] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps in any one of the above methods are implemented.

[0022] The beneficial effects of the present invention compared with the prior art are as follows: By presetting the monitoring time interval to collect displacement characteristic parameters, the present invention can monitor the dynamic changes in the reservoir in real time; based on these real-time data, the injection parameters of carbon dioxide can be dynamically adjusted, so as to respond to the changes in the underground environment in a timely manner and optimize the displacement process; by calculating the volatility between adjacent displacement characteristic parameters in time series and obtaining the displacement characteristic fluctuation coefficient by synthesizing various volatilities, the changes in reservoir conditions can be quantified; based on these quantified data, the injection rate of carbon dioxide can be controlled more precisely, so as to optimize the displacement efficiency of methane; by presetting the displacement characteristic fluctuation threshold and statistically calculating the over-standard rate, it is possible to evaluate whether the current displacement process is stable; once it is found that the over-standard rate is too high, the injection parameters of carbon dioxide can be adjusted in time to avoid damage to the reservoir due to over-exploitation or improper parameters, thus ensuring the long-term stability of the reservoir; due to the real-time monitoring and dynamic adjustment of the injection parameters of carbon dioxide, the displacement effect of carbon dioxide can be maximally utilized, and the production efficiency of methane can be improved; at the same time, by precisely controlling the displacement process, unnecessary carbon dioxide injection and production costs can be reduced, thereby improving the overall economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is a flowchart of a method for dynamically adjusting the carbon dioxide displacement rate in a natural gas hydrate reservoir provided by an embodiment of the present invention;

[0025] Figure 2 is a hardware architecture diagram of an electronic device provided by an embodiment of the present invention;

[0026] Figure 3 is a structural diagram of a device for dynamically adjusting the carbon dioxide displacement rate in a natural gas hydrate reservoir provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0028] Please refer toFigure 1 , an embodiment of the present invention provides a method for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir, and the method includes:

[0029] Step S1: Set corresponding initial carbon dioxide injection parameters for each carbon dioxide injection well, and perform the carbon dioxide injection operation accordingly to start the replacement process of methane;

[0030] Step S2: During the replacement process, collect the replacement characteristic parameters of the target replacement sub-region at a preset monitoring time interval, and the replacement characteristic parameters include methane production rate, temperature, and pressure;

[0031] Step S3: Calculate the volatility between adjacent replacement characteristic parameters in time series; the volatility includes methane production rate volatility, temperature volatility, and pressure volatility;

[0032] Step S4: According to the preset weights corresponding to each replacement characteristic parameter, comprehensively calculate each volatility to obtain the replacement characteristic fluctuation coefficient within the corresponding time interval;

[0033] Step S5: Based on a preset replacement characteristic fluctuation threshold, within a preset time window, count the over-standard rate of multiple replacement characteristic fluctuation coefficients; the over-standard rate is the number of replacement characteristic fluctuation coefficients exceeding the preset replacement characteristic fluctuation threshold, divided by the total number of replacement characteristic fluctuation coefficients within the preset time window;

[0034] Step S6: Dynamically adjust the carbon dioxide injection parameters of the corresponding carbon dioxide injection well according to the over-standard rate.

[0035] In this embodiment, by collecting the replacement characteristic parameters at a preset monitoring time interval, the dynamic changes in the reservoir can be monitored in real time; based on these real-time data, the carbon dioxide injection parameters can be dynamically adjusted, so as to respond to the changes in the underground environment in a timely manner and optimize the replacement process; by calculating the volatility between adjacent replacement characteristic parameters in time series and comprehensively obtaining the replacement characteristic fluctuation coefficient for each volatility, the changes in reservoir conditions can be quantified; based on these quantified data, the carbon dioxide injection rate can be controlled more precisely, so as to optimize the replacement efficiency of methane; by presetting the replacement characteristic fluctuation threshold and counting the over-standard rate, it is possible to evaluate whether the current replacement process is stable; once it is found that the over-standard rate is too high, the carbon dioxide injection parameters can be adjusted in a timely manner to avoid damage to the reservoir due to over-exploitation or improper parameters, thus ensuring the long-term stability of the reservoir; due to the real-time monitoring and dynamic adjustment of the carbon dioxide injection parameters, the replacement effect of carbon dioxide can be maximally utilized, and the methane production efficiency can be improved; at the same time, by precisely controlling the replacement process, unnecessary carbon dioxide injection and production costs can be reduced, thus improving the overall economic benefits.

[0036] The following description Figure 1How the various steps are performed.

[0037] For step S1:

[0038] In step S1, it is first necessary to set parameters for each carbon dioxide injection well, which is specifically implemented as follows:

[0039] Step S11: Obtain basic information of the target natural gas hydrate reservoir, wherein the basic information of the target natural gas hydrate reservoir includes:

[0040] Reservoir geometry: including reservoir thickness, width, length, etc., which are used to subsequently divide replacement sub-areas and determine the location of injection wells;

[0041] Geological structural characteristics: including reservoir lithology, faults, folds and other geological structures, used to analyze the flow and distribution of carbon dioxide in the reservoir;

[0042] Temperature distribution: Temperature affects the solubility and reaction rate of gas. The temperature distribution in the reservoir has an important influence on the stability of natural gas hydrates and the injection efficiency of carbon dioxide.

[0043] Pressure distribution: The pressure distribution in the reservoir determines the initial pressure conditions when carbon dioxide is injected and is also a key factor affecting the displacement efficiency.

[0044] Step S12, reasonably divide the replacement sub-areas according to the basic characteristics of the reservoir to ensure that the physical conditions in each area are relatively uniform, so as to facilitate the targeted setting of injection parameters; consider the geological structure, temperature gradient, pressure difference and other factors of the reservoir to formulate scientific and reasonable division standards; according to the above principles, divide the entire reservoir into several small areas or cells with similar properties; use numerical simulation methods to grid the reservoir to ensure that the physical conditions in each grid are as consistent as possible; for special areas that may appear under complex geological conditions, they can be separately defined as independent replacement sub-areas; each replacement sub-area is provided with at least one carbon dioxide injection well to carry out carbon dioxide injection operations.

[0045] Step S13, obtaining specific status information of natural gas hydrate in each replacement sub-area, including but not limited to hydrate saturation, porosity, etc., for evaluating the replacement potential of the replacement sub-area; specifically, core sampling is performed at selected key locations and sent to the laboratory for comprehensive analysis; or, geophysical detection techniques such as resistivity imaging, sonic logging, etc. are used to directly measure the existence and distribution of underground hydrates.

[0046] Step S14: Input the initial state characteristics of the natural gas hydrate into a preset reservoir natural gas hydrate characteristic analysis model to obtain the substitution potential coefficient of the sub-region. The reservoir natural gas hydrate characteristic analysis model is based on physical or mathematical principles and combines data obtained through means such as geological exploration, geophysical exploration, and laboratory analysis to perform numerical simulations on natural gas hydrate reservoirs. It can simulate the stability of natural gas hydrates in the reservoir, the injection and substitution processes of carbon dioxide, the changes in reservoir pressure and temperature, etc., providing a scientific basis for the exploitation of natural gas hydrates. The reservoir natural gas hydrate characteristic analysis model consists of the following parts:

[0047] Reservoir geological model: Based on geological exploration data, construct a geological structure model of the reservoir's geometry, lithology, faults, folds, etc.

[0048] Fluid flow model: Simulate the flow process of fluids (including natural gas, water, carbon dioxide, etc.) in the reservoir, considering factors such as fluid seepage characteristics, pressure gradient, temperature gradient, etc.

[0049] Thermodynamic model: Simulate the stability of natural gas hydrates in the reservoir, considering the influence of factors such as temperature, pressure, and fluid composition on the stability of natural gas hydrates.

[0050] Chemical reaction model: Simulate the substitution reaction process between carbon dioxide and natural gas hydrates, including reaction rate, reaction conditions, etc.

[0051] The reservoir natural gas hydrate characteristic analysis model evaluates the substitution potential of the reservoir by simulating the substitution process of carbon dioxide and natural gas hydrates under different injection parameters. According to the simulation results, optimize parameters such as carbon dioxide injection rate and injection temperature to improve substitution efficiency and methane recovery rate. Simulate the pressure and temperature changes in the reservoir during carbon dioxide injection to predict the stability and safety of the reservoir.

[0052] Step S15: Using the substitution potential coefficient of the sub-region as a guiding condition, traverse a preset substitution injection parameter database to extract the initial carbon dioxide injection parameters corresponding to the substitution potential coefficient of the sub-region. The initial carbon dioxide injection parameters include the carbon dioxide injection rate, carbon dioxide temperature, and carbon dioxide injection pressure of the corresponding carbon dioxide injection well.

[0053] The substitution injection parameter database is an important tool built on the basis of a large amount of experimental data, numerical simulation results, and expert experience. It is used to provide reasonable initial carbon dioxide injection parameters for natural gas hydrate reservoirs with different substitution potential coefficients. The specific construction is as follows:

[0054] Conduct a large number of laboratory experiments to simulate the stability of natural gas hydrates, the injection and replacement processes of carbon dioxide under different geological conditions, and collect key data such as carbon dioxide injection rate, injection temperature, injection pressure, and methane replacement efficiency during the experiment; use numerical simulation software to establish a numerical model of the natural gas hydrate reservoir, simulate the replacement process under different injection conditions by adjusting the parameters in the numerical model, and record the simulation results; invite experts in the fields of geology, petroleum engineering, etc. to provide suggestions on carbon dioxide injection parameters based on their professional knowledge and practical experience;

[0055] Clean the collected experimental data, numerical simulation results, and expert suggestions to remove duplicate, incorrect, or inconsistent data; standardize the data to ensure that data from different sources have the same format and unit; analyze the correlation between the experimental data, numerical simulation results, and expert suggestions to identify the key factors affecting carbon dioxide injection parameters;

[0056] According to the results of data analysis and processing, design the structure of the database, including table design, field definition, and index creation; use a database management system (such as MySQL, Oracle, etc.) to establish a database and import data according to the designed structure; verify and validate the data in the database to ensure its accuracy and integrity; add indexes to the key fields in the database to improve query efficiency; optimize the database to ensure its stability and performance under high-concurrency access;

[0057] The replacement injection parameter database integrates experimental data, numerical simulation results, and expert experience to provide initial carbon dioxide injection parameters (rate, temperature, pressure) matching the replacement potential coefficient of each sub-region, ensuring efficient and safe methane replacement, optimizing the production efficiency by scientifically setting injection conditions, and ensuring the stability of the reservoir.

[0058] Regarding step S2:

[0059] During the carbon dioxide replacement and production process of the natural gas hydrate reservoir, in order to monitor the reservoir state in real time and dynamically adjust the carbon dioxide injection parameters, it is necessary to accurately collect various replacement characteristic parameters of the target replacement sub-region at a preset monitoring time interval; the replacement characteristic parameters mainly include methane production rate, temperature, and pressure, which can directly reflect the methane replacement efficiency and the stability state of the reservoir in the reservoir. Specifically:

[0060] Methane production rate: By monitoring the methane production rate, the release of methane after carbon dioxide injection can be intuitively understood, thereby evaluating the replacement effect; the speed of the methane production rate directly reflects the activity of the replacement process;

[0061] Temperature: Temperature is an important factor affecting the stability of natural gas hydrates and the carbon dioxide-methane replacement reaction. By monitoring the change of reservoir temperature, it is possible to determine whether the injection of carbon dioxide has caused abnormal fluctuations in the reservoir temperature, and then analyze the impact of these fluctuations on the replacement efficiency and reservoir stability.

[0062] Pressure: Reservoir pressure is another key parameter, which affects the diffusion and dissolution process of carbon dioxide in the reservoir and the release of methane. By monitoring the pressure change, the carbon dioxide injection parameters can be adjusted in a timely manner to keep the reservoir pressure within a reasonable range, so as to optimize the replacement efficiency and ensure reservoir safety.

[0063] In the above process, the setting of the preset monitoring time interval directly affects the timeliness and accuracy of the data, and then affects the subsequent dynamic adjustment of the carbon dioxide injection parameters. If the time interval is too long, important changes in the reservoir state may be missed. If the time interval is too short, the monitoring cost and the interference to the mining operation may increase. Therefore, it is necessary to comprehensively consider the mining stage, reservoir characteristics and monitoring requirements to set the preset monitoring time interval in the carbon dioxide replacement mining of natural gas hydrate reservoirs.

[0064] Specifically, when considering the mining stage, the monitoring frequency can be relatively low in the initial stage of mining, because the physical changes in the reservoir are usually relatively slow at this time. However, as the mining activities progress, the monitoring frequency should be gradually increased to capture the rapid changes in the reservoir response. In the middle stage of mining, with the increase of the mining depth and the change of reservoir conditions, the monitoring frequency needs to be increased accordingly to understand the dynamic changes of the reservoir more accurately. In the later stage of mining, the monitoring frequency can be appropriately reduced, but sufficient monitoring is still required to ensure the safety and stability of the reservoir.

[0065] When considering reservoir characteristics, for reservoirs with high permeability and uniform reservoir, the diffusion and dissolution rate of carbon dioxide is relatively fast, and the reservoir state changes relatively rapidly. Then a shorter monitoring time interval is set to capture the changes in the reservoir state in a timely manner. For reservoirs with low permeability and complex reservoir, the diffusion and dissolution rate of carbon dioxide is relatively slow, and the reservoir state changes relatively slowly. Then the monitoring time interval is appropriately extended to reduce unnecessary monitoring costs and interference to the mining operation.

[0066] When considering monitoring requirements, if it is necessary to monitor the reservoir state in real time to quickly respond to abnormal situations (such as abnormal increase in reservoir pressure, abnormal decrease in temperature, etc.), a shorter monitoring time interval is set. If only regular understanding of the reservoir state is needed for long-term planning (such as evaluating the carbon dioxide sequestration effect, predicting reservoir stability, etc.), a relatively longer monitoring time interval is set.

[0067] In actual operation, a reasonable monitoring time interval is set by comprehensively considering and weighing the above factors; for example, in the initial stage of mining and when the reservoir permeability is high, a shorter time interval of monitoring every few hours can be set; while in the later stage of mining and when the reservoir permeability is low, a longer time interval of monitoring once a week or once a month can be set.

[0068] Regarding step S3:

[0069] Step S3 quantifies the variation of these parameters over time by calculating the volatility between adjacent replacement characteristic parameters (methane production rate, temperature, and pressure) in time series. Volatility is an important indicator to measure the severity of parameter changes and can help identify the dynamic changes of reservoir conditions; the specific calculation method is as follows:

[0070] Obtain the time series data from step S2, ensuring that the data has been preliminarily cleaned to remove outliers and noise interference. For each target replacement sub-region, sort out a series of data points of methane production rate, temperature, and pressure in time order.

[0071] Specifically, the calculation formula for the volatility of methane production rate is:

[0072]

[0073] Where, I R represents the volatility of methane production rate, R CH4 (t) represents the methane production rate collected at the t-th time node, and R CH4 (t - 1) represents the methane production rate collected at the (t - 1)-th time node.

[0074] The calculation formula for temperature volatility is:

[0075]

[0076] Where, I T represents the temperature volatility, T(t) represents the temperature collected at the t-th time node, and T(t - 1) represents the temperature collected at the (t - 1)-th time node;

[0077] The calculation formula for pressure volatility is:

[0078]

[0079] Where, I P represents the pressure volatility, P(t) represents the pressure collected at the t-th time node, and P(t - 1) represents the pressure collected at the (t - 1)-th time node.

[0080] In this step, by calculating the volatility at adjacent time points, the change ranges of methane production rate, temperature, and pressure can be accurately quantified, providing objective data support to help identify the dynamic changes in reservoir conditions; as an indicator of rapid changes, volatility enables the system to promptly capture any significant changes in reservoir state, providing an immediate basis for subsequent dynamic adjustment of injection parameters and enhancing the system's real-time response ability; statistical analysis of the volatility results helps to discover potential trends or anomalies, supports more scientific and reasonable decision-making, and improves the safety and efficiency of the entire carbon dioxide replacement mining process.

[0081] Regarding step S4:

[0082] In step S4, according to the preset weights corresponding to each replacement characteristic parameter (methane production rate, temperature, and pressure), the volatilities of each item are comprehensively calculated to obtain the replacement characteristic fluctuation coefficient within the corresponding time interval. Integrating different types of fluctuation information into a comprehensive index for evaluating the changes in reservoir state, the specific calculation method is as follows:

[0083] Assign a preset weight to each replacement characteristic parameter (methane production rate, temperature, and pressure) to reflect the importance of each parameter in the replacement process; the weight assignment can be based on historical data, expert experience, or previous experimental results to determine which parameter has a greater impact on replacement efficiency and reservoir stability; for each replacement characteristic parameter, multiply the volatility of each parameter calculated in step S3 by its corresponding weight to obtain the weighted volatility; add up the weighted volatilities of all parameters to obtain the replacement characteristic fluctuation coefficient; the replacement characteristic fluctuation coefficient reflects the overall fluctuation situation of the replacement process within the corresponding time window after considering the importance of each parameter, and is used to evaluate the stability and efficiency of the replacement process, providing a basis for subsequent dynamic adjustment. The specific formula is as follows:

[0084]

[0085] Where, represents the replacement characteristic fluctuation coefficient in the i-th time interval, represents the volatility of methane production rate in the i-th time interval, represents the temperature volatility in the i-th time interval, represents the pressure volatility in the i-th time interval; ω R 、ω T and ω P represent the weight coefficients corresponding to the volatility of methane production rate, temperature volatility, and pressure volatility respectively; by means of weighted summation of each volatility, a comprehensive consideration of multiple replacement characteristic parameters is achieved, and a replacement characteristic fluctuation coefficient that can reflect the overall situation is obtained.

[0086] Regarding step S5:

[0087] In step S5, by statistically analyzing the displacement characteristic fluctuation coefficient, it is judged whether the current displacement process is stable, and based on this, it is decided whether to adjust the carbon dioxide injection parameters; the following is a detailed introduction to step S5:

[0088] Step S51: The preset displacement characteristic fluctuation threshold is determined according to historical data, simulation calculations, and engineering experience, and is used to measure the acceptable range of fluctuations in various characteristic parameters during the displacement process; the preset displacement characteristic fluctuation threshold is used as a standard to judge whether the displacement process is stable, and fluctuations exceeding this threshold are considered abnormal conditions;

[0089] Step S52: The preset time window refers to the time period length for data analysis and evaluation within a continuous time period; it is determined according to specific geological conditions, displacement rate, and the sampling frequency of monitoring equipment to ensure the representativeness and timeliness of the data;

[0090] Step S53: At the end of each preset time window, collect the volatility of all monitored displacement characteristic parameters (such as methane production rate, temperature, pressure) during this time period; use the volatility of each characteristic parameter obtained in step S4 and its corresponding weight to calculate the comprehensive displacement characteristic fluctuation coefficient;

[0091] For each displacement characteristic fluctuation coefficient, check whether it exceeds the preset displacement characteristic fluctuation threshold; if it exceeds, mark it as "exceeding the standard"; the exceeding rate refers to the ratio of the number of displacement characteristic fluctuation coefficients exceeding the preset displacement characteristic fluctuation threshold to the total number of fluctuation coefficients within the preset time window; if the exceeding rate is low and within the acceptable range, it indicates that the current carbon dioxide injection parameter setting is relatively reasonable, the displacement process is relatively stable, and the existing operations can be continued; conversely, if the exceeding rate is high, it means that there may be some adverse factors affecting the displacement efficiency or reservoir stability, and measures need to be taken in a timely manner for adjustment.

[0092] In this step, by presetting the displacement characteristic fluctuation threshold and statistically analyzing the exceeding rate, this step can comprehensively evaluate the stability of the displacement process and detect abnormal conditions in a timely manner; at the same time, determining the threshold using historical data, simulation calculations, and engineering experience enhances the accuracy and reliability of the evaluation; in addition, the setting of the preset time window ensures the representativeness and timeliness of data analysis, helps to adjust the carbon dioxide injection parameters in a timely manner, optimize the displacement process, improve the displacement efficiency, and ensure reservoir stability.

[0093] Regarding step S6:

[0094] Step S6 is to dynamically adjust the injection parameters (such as carbon dioxide injection rate, temperature, and pressure) of each carbon dioxide injection well based on the over-standard rate calculated in step S5 to optimize the methane replacement efficiency and ensure reservoir stability; the aim is to improve the production efficiency, reduce environmental impacts, and ensure the safety and economy of operations by responding in real time to changes in reservoir conditions; the specific implementation is as follows:

[0095] According to the over-standard rate statistically obtained in step S5, evaluate whether the current carbon dioxide injection parameters are suitable for the current reservoir situation; a lower over-standard rate indicates a stable reservoir state and the existing parameters can be maintained; a higher over-standard rate indicates that there may be problems and parameter adjustment is required;

[0096] It is necessary to formulate an adjustment strategy in advance: if the over-standard rate is within an acceptable range, for example, the over-standard rate < 10%, it means that the current injection parameters are relatively reasonable and the existing operations can continue, but be vigilant and continuously monitor; when the over-standard rate reaches a certain level, for example, the over-standard rate is between 10% - 30%, consider making fine adjustments to some key parameters, such as slightly decreasing or increasing the carbon dioxide injection rate, to observe its impact on the reservoir; if the over-standard rate increases significantly, for example, the over-standard rate > 30%, it indicates that the reservoir conditions have changed greatly, which may lead to unstable methane production or potential safety hazards, and the following measures need to be taken immediately:

[0097] Emergency stop: For extremely severe fluctuations, first suspend the injection operation and check the accuracy of the equipment and data acquisition system;

[0098] Substantial parameter adjustment: According to the specific situation, substantially adjust the carbon dioxide injection rate, temperature, or pressure, such as increasing the injection rate to accelerate the replacement process, or decreasing the pressure to avoid excessive reservoir disturbance.

[0099] In this step, by dynamically adjusting the carbon dioxide injection parameters according to the over-standard rate, it can quickly adapt to changes in reservoir conditions, optimize the methane replacement efficiency, and ensure reservoir stability at the same time; in addition, the pre-formulated adjustment strategy makes the parameter adjustment more orderly and controllable, reducing the risk of blind operation; the introduction of measures such as emergency stop and substantial adjustment further improves the safety of operations and the ability to respond to emergencies.

[0100] As Figure 2 、 Figure 3 shown, the embodiments of the present invention provide a device for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir. The device embodiments can be implemented by software, or by hardware, or by a combination of software and hardware. From the hardware level, as Figure 2 shown, it is a hardware architecture diagram of an electronic device where the device for dynamically adjusting the carbon dioxide replacement rate in a natural gas hydrate reservoir provided by the embodiments of the present invention is located. Except for Figure 2In addition to the processor, memory, network interface, and non-volatile memory shown, the electronic device where the device is located in the embodiment usually may also include other hardware, such as a forwarding chip responsible for processing packets, etc. Taking software implementation as an example, as Figure 3 shown, as a device in a logical sense, it is formed by the CPU of the electronic device where it is located reading the corresponding computer program in the non-volatile memory into the memory and running it.

[0101] Such as Figure 3 shown, a device for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir provided in this embodiment includes:

[0102] A parameter setting module, configured to set corresponding initial carbon dioxide injection parameters for each carbon dioxide injection well and start the replacement process of methane;

[0103] A real-time monitoring module, configured to collect replacement characteristic parameters of a target replacement sub-region at a preset time interval during the replacement process, where the replacement characteristic parameters include methane production rate, temperature, and pressure;

[0104] A volatility calculation unit, configured to calculate the volatility between adjacent replacement characteristic parameters in time series according to the data obtained by the real-time monitoring module, including methane production rate volatility, temperature volatility, and pressure volatility;

[0105] A fluctuation coefficient calculation unit, configured to comprehensively calculate each volatility according to the preset weights corresponding to each replacement characteristic parameter, so as to obtain the replacement characteristic fluctuation coefficient within the corresponding time interval;

[0106] An over-standard rate statistics module, configured to statistically calculate the over-standard rate of multiple replacement characteristic fluctuation coefficients within a preset time window based on a preset replacement characteristic fluctuation threshold; the over-standard rate refers to the number of replacement characteristic fluctuation coefficients exceeding the preset replacement characteristic fluctuation threshold divided by the total number of replacement characteristic fluctuation coefficients within the preset time window;

[0107] An injection parameter dynamic adjustment module, configured to dynamically adjust the carbon dioxide injection parameters of the corresponding carbon dioxide injection well according to the over-standard rate.

[0108] It can be understood that the structure schematically shown in the embodiments of the present invention does not constitute a specific limitation on a device for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir. In other embodiments of the present invention, a device for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or have different component arrangements. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0109] For the information interaction, execution process, etc. between the modules in the above device, since they are based on the same concept as the method embodiments of the present invention, the specific content can be referred to the description in the method embodiments of the present invention, and will not be elaborated here.

[0110] An embodiment of the present invention also provides an electronic device, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, a method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir in any embodiment of the present invention is implemented.

[0111] An embodiment of the present invention also provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the processor is caused to execute a method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir in any embodiment of the present invention.

[0112] Specifically, a system or device equipped with a storage medium can be provided. Software program codes for implementing the functions of any one of the above embodiments are stored on the storage medium, and the computer (or CPU or MPU) of the system or device is caused to read and execute the program codes stored in the storage medium.

[0113] In this case, the program code read from the storage medium itself can implement the functions of any one of the above embodiments. Therefore, the program code and the storage medium storing the program code constitute a part of the present invention.

[0114] Embodiments of the storage medium for providing program codes include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Optionally, the program codes can be downloaded from a server computer via a communication network.

[0115] In addition, it should be clear that not only can the functions of any one of the above embodiments be implemented by executing the program codes read by the computer, but also by the operating system etc. operating on the computer based on the instructions of the program codes to complete part or all of the actual operations.

[0116] In addition, it can be understood that the program codes read from the storage medium are written into the memory provided in the expansion board inserted into the computer or the memory provided in the expansion module connected to the computer, and then based on the instructions of the program codes, the CPUs etc. installed on the expansion board or expansion module are caused to execute part and all of the actual operations, thereby implementing the functions of any one of the above embodiments.

[0117] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0118] Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps including those of the above method embodiments; and the foregoing storage medium includes: various media such as ROM, RAM, magnetic disk or optical disk that can store program codes.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir, characterized in that: The method comprises: Setting corresponding initial CO2 injection parameters for each CO2 injection well, and performing CO2 injection operations accordingly to start the methane replacement process; During the replacement process, the replacement characteristic parameters of the target replacement sub-region are collected at preset monitoring time intervals; Calculate the volatility between adjacent permutation feature parameters in time series; According to the preset weights corresponding to the various replacement characteristic parameters, the volatility of each item is comprehensively calculated to obtain the replacement characteristic volatility coefficient within the corresponding time interval; Based on a preset replacement feature fluctuation threshold, within a preset time window, the exceeding rate of multiple replacement feature fluctuation coefficients is counted; According to the exceeding rate, the CO2 injection parameters of the corresponding CO2 injection wells are dynamically adjusted.

2. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 1, characterized in that: Set the corresponding initial CO2 injection parameters for each CO2 injection well, including: Obtain basic information of target natural gas hydrate reservoir; Based on the basic information of the target natural gas hydrate reservoir, the target natural gas hydrate reservoir is divided into a plurality of replacement sub-areas, wherein each replacement sub-area is provided with at least one carbon dioxide injection well; For each replacement sub-region, the initial state characteristics of the natural gas hydrate in the replacement sub-region are collected; Inputting the initial state characteristics of the natural gas hydrate into a preset reservoir natural gas water characteristic analysis model to obtain a sub-region replacement potential coefficient; Taking the displacement potential coefficient of the sub-region as a guide condition, traversing the preset displacement injection parameter database, extracting the initial carbon dioxide injection parameters corresponding to the displacement potential coefficient of the sub-region.

3. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 2, characterized in that: The replacement characteristic parameters include methane production rate, temperature and pressure.

4. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 3, characterized in that: The initial carbon dioxide injection parameters include a carbon dioxide injection rate, a carbon dioxide temperature and a carbon dioxide injection pressure corresponding to the carbon dioxide injection well.

5. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 4, characterized in that: The fluctuation rate includes the fluctuation rate of methane production rate, the fluctuation rate of temperature and the fluctuation rate of pressure; The calculation formula of the methane production rate fluctuation rate is: Among them, I R represents the fluctuation rate of methane production, R CH4 (t) represents the methane production rate collected at the tth time node, R CH4 (t-1) represents the methane production rate collected at the t-1th time node; The calculation formula of the temperature fluctuation rate is: Among them, I T represents the temperature fluctuation rate, T(t) represents the temperature collected at the tth time node, and T(t-1) represents the temperature collected at the t-1th time node; The calculation formula of the pressure fluctuation rate is: Among them, I P represents the pressure fluctuation rate, P(t) represents the pressure collected at the t-th time node, and P(t-1) represents the pressure collected at the t-1th time node.

6. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 5, characterized in that: According to the preset weights corresponding to the various replacement characteristic parameters, the volatility is comprehensively calculated, including: in, represents the permutation characteristic fluctuation coefficient in the i-th time interval, represents the fluctuation rate of methane production in the i-th time interval, represents the temperature fluctuation rate in the i-th time interval, represents the pressure fluctuation rate in the i-th time interval; ω R ,ω T and ω P They represent the weight coefficients corresponding to the methane production rate fluctuation rate, temperature fluctuation rate and pressure fluctuation rate respectively.

7. The method for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir according to claim 2, characterized in that: The basic information of the target natural gas hydrate reservoir includes the geometric size, geological structure characteristics, temperature distribution and pressure distribution of the reservoir.

8. A device for dynamically adjusting the carbon dioxide replacement rate of a natural gas hydrate reservoir, characterized in that: include: A parameter setting module is used to set the corresponding initial carbon dioxide injection parameters for each carbon dioxide injection well and start the methane replacement process; A real-time monitoring module is used to collect replacement characteristic parameters of the target replacement sub-region at preset time intervals during the replacement process; A volatility calculation unit, used to calculate the volatility between adjacent replacement characteristic parameters in time series according to the data obtained by the real-time monitoring module; The fluctuation coefficient calculation unit is used to comprehensively calculate various fluctuation rates according to the preset weights corresponding to various replacement characteristic parameters, so as to obtain the replacement characteristic fluctuation coefficient within the corresponding time interval; An excess rate statistics module is used to count excess rates of multiple replacement feature fluctuation coefficients within a preset time window based on a preset replacement feature fluctuation threshold; The injection parameter dynamic adjustment module is used to dynamically adjust the carbon dioxide injection parameters of the corresponding carbon dioxide injection well according to the exceeding rate.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed in a computer, the computer is caused to execute the method according to any one of claims 1 to 7.

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