Fused salt heating superheated steam generation system and control method thereof

Abstract

This invention provides a molten salt-heated superheated steam generation system and its control method, belonging to the field of oilfield extraction technology. The system includes: a water supply device, an evaporation device, and a superheated steam generation device connected in sequence; a molten salt flow pipe is provided to provide a heat source to the steam generation device and the evaporation device; the water supply device is used to transfer preheated low-temperature feed water to the evaporation device, so that the evaporation device converts the preheated low-temperature feed water into wet saturated steam; the superheated steam generation device is used to convert the wet saturated steam into superheated steam for steam injection; and a control device is used to control the operating status of the water supply device, the evaporation device, and the superheated steam generation device based on steam injection demand. This invention effectively solves the problem of insufficient response to dynamic steam injection demand in the prior art, significantly improves the system's adaptability and operating efficiency, and meets the needs of heavy oil extraction under complex operating conditions.

Description

Technical Field

[0001] This invention relates to the field of oilfield development technology, specifically to a molten salt heating superheated steam generation system and a control method for the molten salt heating superheated steam generation system. Background Technology

[0002] In the current heavy oil extraction process, steam injection technology is one of the key links in enhancing oil recovery. Steam injection systems typically require high-temperature, high-pressure superheated steam to meet the needs of oil wells. However, traditional steam injection systems mainly rely on gas-fired boilers to generate steam, which not only leads to high energy consumption and large carbon emissions, but also limits the widespread application of the system.

[0003] To address these issues, existing technologies have gradually explored molten salt heating technology, using molten salt as a heat storage and transfer medium and off-peak electricity or green electricity as the primary energy source to produce superheated steam. However, existing molten salt steam injection schemes have shortcomings in the following key technological aspects:

[0004] The existing system lacks dynamic adaptability to steam injection demand: it typically operates under fixed conditions and lacks the ability to respond in real time to the dynamic demands (changes in flow rate, temperature, and pressure) of the steam injection well. As the production stage of the oil well changes, the steam injection demand exhibits nonlinear and dynamic fluctuations, while the fixed parameter operation mode can easily lead to steam waste or insufficient supply, reducing steam injection efficiency.

[0005] Insufficient precision in mixer control: During the mixing process of superheated steam and saturated water, existing technologies lack high-precision, real-time control schemes, making it impossible to ensure that the temperature and flow rate of the mixed steam consistently meet the injection requirements. This insufficient control may lead to unstable superheat or flow rate deviations in the mixed steam, directly affecting downhole oil production efficiency.

[0006] In summary, existing technologies cannot effectively cope with the dynamic changes in steam injection demand, and the accuracy of the mixing process also faces technical bottlenecks. There is an urgent need for a dynamic control method that can adapt to changes in steam injection demand in real time, optimize the operating parameters of the mixer, and ensure the stability of the mixed steam and the efficiency of steam injection. Summary of the Invention

[0007] The purpose of this invention is to provide a molten salt heating superheated steam generation system and its control method, so as to at least solve the problems that the prior art cannot effectively cope with the dynamic changes in steam injection demand and the lack of precision in the blending process.

[0008] To achieve the above objectives, a first aspect of the present invention provides a molten salt heating superheated steam generation system, the system comprising: a water supply device, an evaporation device, and a superheated steam generation device connected in sequence; a molten salt flow pipe provided from the superheated steam generation device to the evaporation device for providing a heat source to the superheated steam generation device and the evaporation device; the water supply device for preheating low-temperature input water and transmitting the preheated low-temperature input water to the evaporation device, so that the evaporation device converts the preheated low-temperature input water into wet saturated steam; the superheated steam generation device for converting the wet saturated steam into superheated steam for steam injection requirements; and a control device for controlling the operating status of the water supply device, the evaporation device, and the superheated steam generation device based on steam injection requirements.

[0009] Optionally, the water supply device includes: an oilfield produced water supply pipeline for inputting oilfield produced water as low-temperature supply water for the water supply device; a preheating module connected to the oilfield produced water supply pipeline for preheating the low-temperature supply water; the preheating module is connected to an evaporation device via a pipeline for transmitting the preheated low-temperature supply water to the evaporation device.

[0010] Optionally, the preheating module includes: a wet saturated steam preheating module, a solar preheating module, and a geothermal energy preheating module, which are combined to perform preheating of the low-temperature supplied water; the wet saturated steam of the wet saturated steam preheating module is obtained by separating the wet saturated steam output from the evaporator and flows into the wet saturated steam preheating module through a first wet steam pipeline; another part of the wet saturated steam output from the evaporator flows into the evaporator through a second wet steam pipeline.

[0011] Optionally, the solar preheating module includes: a concentrating solar collector, which is installed between the wet saturated steam preheating module and the oilfield produced water supply pipeline, for performing the first stage of preheating on the low-temperature supply water; the geothermal preheating module includes: a geothermal heat exchanger, which is installed in parallel with the concentrating solar collector, and is combined with the concentrating solar collector to perform the first stage of preheating on the low-temperature supply water.

[0012] Optionally, the geothermal heat exchanger is equipped with a three-way valve; the inlet of the three-way valve is used to receive the heating medium of the geothermal heat exchanger; the outlet of the three-way valve is connected to the preheating module and the molten salt heating module respectively; the opening and closing degree of the three-way valve connected to the preheating module and the molten salt heating module is controlled by the control module.

[0013] Optionally, the control module is configured to: construct a corresponding LSTM model based on historical steam injection data, real-time steam demand, and oil well operating parameters to predict future steam injection demand at a predetermined time; determine the preheating demand for low-temperature water supply based on the steam injection demand and the heat exchange efficiency of the evaporator; determine the supplementary heat exchange power of the geothermal energy preheating module for performing low-temperature water supply preheating based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module; generate a control scheme for the valve opening degree of the three-way valve to the preheating module based on the supplementary heat exchange power of the geothermal energy preheating module, and generate a control scheme for the valve opening degree of the three-way valve to the molten salt heating module based on the remaining heat exchange power of the geothermal energy preheating module.

[0014] Optionally, determining the supplementary heat exchange power of the geothermal preheating module performing low-temperature water supply preheating based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module includes: constructing a corresponding objective function based on a collaborative game theory algorithm, treating the preheating module and the molten salt heating module as game players, to maximize the steam injection demand satisfaction rate and molten salt thermal storage efficiency; and iteratively solving the objective function based on the Lagrange relaxation method to obtain the optimal supplementary heat exchange power of the geothermal preheating module performing low-temperature water supply preheating.

[0015] Optionally, the objective function is expressed as:

[0016]

[0017] in, and Preset weighting factors that respectively represent the importance of produced water preheating requirements and molten salt thermal storage requirements; Geothermal heat supply allocated for preheating extracted water; Total preheating requirements for produced water; For the geothermal heat supplied to molten salt heating; The target requirement for heating molten salt.

[0018] Optionally, the evaporation device includes multiple heat exchangers; each heat exchanger is connected in series via pipes, with the water inlet of the first heat exchanger connected to the water outlet of the water supply device, and the water outlet of the last heat exchanger being the output port of the wet saturated steam; the molten salt flow pipe flows from the last heat exchanger to the first heat exchanger, and then flows back from the first heat exchanger to the molten salt heating module.

[0019] Optionally, the superheated steam generating device includes: a steam-water separator for separating the incoming wet saturated steam into dry steam and saturated water; the dry steam and saturated water output from the steam-water separator are connected to the superheater and the mixer through the dry steam pipeline and the separated water pipeline, respectively; the superheater performs heat exchange with the molten salt flow pipeline to convert the dry steam into superheated steam.

[0020] Optionally, the superheater is connected to another inlet of the mixer via a first superheated steam pipeline to collect superheated steam into the mixer; the mixer is used to perform superheated steam and saturated water mixing based on the gas injection requirements to obtain superheated steam that meets the gas injection requirements, and outputs the superheated steam to the steam injection well via a second superheated steam pipeline.

[0021] Optionally, the control module is configured to: construct corresponding heat balance models and flow balance models based on the state information of superheated steam and saturated water entering the mixer; determine the mixing ratio of superheated steam and saturated water based on the heat balance models and flow balance models; and adjust the valve opening of the mixer in real time according to the mixing ratio.

[0022] Optionally, the heat balance model is expressed as:

[0023]

[0024] The flow balance model is expressed as follows:

[0025]

[0026] in, , and These are the mass flow rates of the mixed steam, the superheated steam, and the saturated water, respectively. , and These are the specific enthalpy of mixed steam, the specific enthalpy of superheated steam, and the specific enthalpy of saturated water, respectively.

[0027] Optionally, the mixing ratio of superheated steam and saturated water is determined based on the heat balance model and the flow balance model, including: performing a joint solution based on the heat balance model and the flow balance model to obtain the flow ratio of superheated steam and saturated water, so as to determine the mixing ratio of superheated steam and saturated water.

[0028] Optionally, after adjusting the valve opening of the mixer in real time according to the mixing ratio, the control device is further configured to: collect the state parameters of the superheated steam required for steam injection in real time, and identify the deviation value between the superheated steam and the state parameters of the target superheated steam; and execute a PID control algorithm based on the deviation value to correct the valve opening of the mixing device, so as to keep the deviation value between the actual superheated steam state parameters and the target superheated steam state parameters within a preset difference threshold range.

[0029] A second aspect of the present invention provides a control method for a molten salt heated superheated steam generation system. The method is applied to the aforementioned molten salt heated superheated steam generation system. The method includes: collecting real-time steam injection demand information, and performing target operating state simulations for a water supply device, an evaporator, and a superheated steam generation device based on the steam injection demand information; generating control schemes for the water supply device, evaporator, and superheated steam generation device based on the deviation values ​​between the real-time operating states of the water supply device, evaporator, and superheated steam generation device and their corresponding target operating states; and executing the control schemes to respectively adjust the states of the water supply device, evaporator, and superheated steam generation device.

[0030] Optionally, the water supply device includes: an oilfield produced water supply pipeline for inputting oilfield produced water as low-temperature supply water for the water supply device; a preheating module connected to the oilfield produced water supply pipeline for preheating the low-temperature supply water; the preheating module is connected to an evaporation device via a pipeline for transmitting the preheated low-temperature supply water to the evaporation device.

[0031] Optionally, the preheating module includes: a wet saturated steam preheating module, a solar preheating module, and a geothermal preheating module, combined for preheating the low-temperature supplied water; the wet saturated steam in the wet saturated steam preheating module is obtained by separating the wet saturated steam output from the evaporator and flows into the wet saturated steam preheating module via a first wet steam pipeline; another portion of the wet saturated steam output from the evaporator flows into the evaporator via a second wet steam pipeline; the solar preheating module includes: a concentrating solar collector, installed between the wet saturated steam preheating module and the oilfield produced water. Between the water supply pipes, a first-stage preheating is performed on the low-temperature supply water; the geothermal energy preheating module includes: a geothermal heat exchanger, arranged in parallel with the concentrating solar collector, which, in combination with the concentrating solar collector, performs the first-stage preheating on the low-temperature supply water; the geothermal heat exchanger is equipped with a three-way valve; the inlet of the three-way valve is used to receive the heating medium of the geothermal heat exchanger; the outlet of the three-way valve is respectively connected to the preheating module and the molten salt heating module; the opening and closing degree of the three-way valve connected to the preheating module and the molten salt heating module is controlled by the control module.

[0032] Optionally, the generation rule for the control scheme of the preheating module is as follows: based on historical steam injection data, real-time steam demand, and oil well operating parameters, a corresponding LSTM model is constructed to predict the steam injection demand at a predetermined time in the future; based on the steam injection demand and the heat exchange efficiency of the evaporator, the preheating demand for low-temperature water supply is determined; based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module, the supplementary heat exchange power of the geothermal energy preheating module for performing low-temperature water supply preheating is determined; based on the supplementary heat exchange power of the geothermal energy preheating module, a control scheme for the valve opening degree of the three-way valve to the preheating module is generated, and based on the remaining heat exchange power of the geothermal energy preheating module, a control scheme for the valve opening degree of the three-way valve to the molten salt heating module is generated, which serves as the control scheme for the preheating module.

[0033] On the other hand, the present invention provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described control method for a molten salt heating superheated steam generation system.

[0034] Through the above technical solution, the present invention constructs a highly efficient and flexible steam injection generation system by sequentially connecting a water supply device, an evaporation device, and a superheated steam generator, combined with a molten salt flow pipeline to provide a heat source. The water supply device preheats the low-temperature input water, improving heat exchange efficiency and reducing the heat load on the evaporation device, thereby achieving efficient utilization of water resources and thermal energy. The evaporation device converts the preheated input water into wet saturated steam, providing a stable foundation for the subsequent generation of superheated steam. The superheated steam generator further heats the wet saturated steam to generate superheated steam that meets the steam injection requirements. The control device dynamically adjusts the operating status of each device based on real-time steam injection demand, optimizing the entire process from water preheating to steam superheating, ensuring the accuracy and stability of the output steam parameters. The overall solution effectively solves the problem of insufficient response to dynamic steam injection demand in existing technologies, significantly improving the system's adaptability and operating efficiency, and meeting the needs of heavy oil extraction under complex operating conditions.

[0035] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0036] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0037] Figure 1 This is a system structure diagram of a molten salt heating superheated steam generation system provided in one embodiment of the present invention;

[0038] Figure 2This is a schematic diagram of the specific structure of a molten salt heating superheated steam generation system provided in one embodiment of the present invention;

[0039] Figure 3 This is a flowchart of the steps of a control method for a molten salt heating superheated steam generation system provided in one embodiment of the present invention.

[0040] Explanation of reference numerals in the attached figures

[0041] 1-Preheating water pipe; 2-Evaporator; 3-Steam extraction pipe; 4-First wet steam pipe; 5-Second wet steam pipe; 6-Second hot brine pipe; 7-Steam-water separator; 8-Separated water pipe; 9-Dry steam pipe; 10-Superheater; 11-First superheated steam pipe; 12-Mixer; 13-Second superheated steam pipe; 14-First hot brine pipe; 15-Cold brine pipe; 16-Preheater; 17-Oilfield produced water supply pipe; 18-Condensate pipe. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0043] Figure 1 This is a system structure diagram of a molten salt heating superheated steam generation system provided in one embodiment of the present invention. Figure 1 As shown, this invention provides a molten salt heating superheated steam generation system, comprising: a water supply device, an evaporation device, and a superheated steam generation device connected in sequence; a molten salt flow pipe provided from the superheated steam generation device to the evaporation device for providing a heat source to the superheated steam generation device and the evaporation device; the water supply device preheats the low-temperature input water and transmits the preheated low-temperature input water to the evaporation device, so that the evaporation device converts the preheated low-temperature input water into wet saturated steam; the superheated steam generation device converts the wet saturated steam into superheated steam for steam injection requirements; and a control device for controlling the operating status of the water supply device, the evaporation device, and the superheated steam generation device based on steam injection requirements.

[0044] Preferably, the water supply device includes: an oilfield produced water supply pipeline for inputting oilfield produced water as low-temperature water for the water supply device; a preheating module connected to the oilfield produced water supply pipeline for preheating the low-temperature water; and the preheating module connected to an evaporation device via a pipeline for transmitting the preheated low-temperature water to the evaporation device.

[0045] In this embodiment of the invention, the oilfield produced water supply pipeline, as one of the core components of the water supply device, is used to stably input oilfield produced water into the system, providing a sufficient water source for steam production. Since oilfield produced water typically has a low initial temperature and high silicon content, directly using it in the evaporation process can easily cause scaling in the heat exchanger and reduce system efficiency; therefore, preliminary pretreatment is required.

[0046] The preheating module is connected to the oilfield produced water supply pipeline and uses high-efficiency heat exchange technology to preheat the low-temperature feed water. During the preheating process, multiple heat sources, such as the waste heat of the molten salt system and the extraction heat of wet saturated steam, can be utilized to raise the supply water temperature from the initial 40-70℃ to 230-250℃, effectively reducing the heat load on the evaporator and minimizing the risk of scaling within the evaporator. The preheated low-temperature feed water is then transported to the evaporator through pipelines, further improving the thermal efficiency of the evaporation process and the system stability.

[0047] Based on the present invention, the efficient preheating and stable delivery of oilfield produced water solves the problems of evaporator scaling and low thermal efficiency caused by poor water quality and large temperature differences in traditional systems. Furthermore, by optimizing the matching of water supply temperature and evaporation conditions, the overall energy utilization rate of the system is significantly improved. In addition, the introduction of the preheating module makes it possible to integrate multiple heat sources into the system, such as utilizing external heat sources like solar energy and geothermal energy to further improve preheating efficiency, creating conditions for the application of green energy. Overall, this water supply device provides ideal water supply conditions for subsequent evaporation and superheated steam generation devices, ensuring the efficient and stable operation of the system and meeting dynamic steam injection requirements.

[0048] Preferably, the preheating module includes: a wet saturated steam preheating module, a solar preheating module, and a geothermal energy preheating module, which are combined to perform preheating of the low-temperature supplied water; the wet saturated steam of the wet saturated steam preheating module is obtained by separating the wet saturated steam output from the evaporator and flows into the wet saturated steam preheating module through a first wet steam pipeline; another part of the wet saturated steam output from the evaporator flows into the evaporator through a second wet steam pipeline.

[0049] In this embodiment of the invention, the preheating module consists of a wet saturated steam preheating module, a solar preheating module, and a geothermal energy preheating module. These three modules work synergistically to efficiently preheat the low-temperature supplied water. This modular preheating structure not only improves the system's thermal energy utilization rate but also provides technical support for the flexible integration of multiple heat sources.

[0050] The wet saturated steam preheating module achieves efficient heat recovery by utilizing the wet saturated steam output from the evaporator. After separation, a portion of the wet saturated steam flows into the wet saturated steam preheating module through the first wet steam pipeline to preheat the low-temperature feed water. This method not only recovers the sensible and latent heat of the wet saturated steam but also avoids heat waste caused by direct discharge, while reducing the overall energy consumption of the evaporator. The other portion of the wet saturated steam is returned to the evaporator through the second wet steam pipeline to regulate the stability of the evaporator and further optimize heat distribution.

[0051] As a way to utilize clean energy, the solar preheating module uses a high-efficiency solar collector to convert collected solar heat into a heat source for supplying cold water. This module not only reduces dependence on traditional energy sources but also takes advantage of the difference in grid load between day and night, enabling the system to operate in conjunction with green electricity and improving energy efficiency.

[0052] The geothermal preheating module extracts geothermal resources through a geothermal heat exchanger to initially heat the low-temperature feed water. This design, utilizing low-temperature geothermal resources, fully leverages the advantages of geothermal resources in primary heat energy replenishment, reduces the load on the molten salt system during the preheating stage, and provides stable water supply conditions for subsequent evaporation units. Furthermore, drilling is an essential operation in heavy oil steam injection development, and geothermal resource development also requires drilling. Combining steam injection drilling with geothermal development drilling allows for the sharing of drilling resources, reducing overall construction costs. This integrated utilization avoids the waste caused by repeated drilling and fully utilizes the value of drilling equipment. Oilfield blocks are typically located in geologically active areas, which are often accompanied by abundant geothermal resources. Steam injection development itself requires deep drilling, through which geothermal fluids (such as geothermal hot water or geothermal steam) can be directly obtained. This natural geothermal resource acquisition method provides a low-cost, stable heat source for the preheating and heating processes of the steam injection system.

[0053] Preferably, the solar preheating module includes: a concentrating solar collector, which is installed between the wet saturated steam preheating module and the oilfield produced water supply pipeline, for performing the first stage of preheating on the low-temperature supply water; the geothermal preheating module includes: a geothermal heat exchanger, which is installed in parallel with the concentrating solar collector, and is combined with the concentrating solar collector to perform the first stage of preheating on the low-temperature supply water.

[0054] In this embodiment of the invention, the solar preheating module includes a concentrating solar collector, mainly installed between the wet saturated steam preheating module and the oilfield produced water supply pipeline, for performing the first stage of preheating on the low-temperature supplied water. The concentrating solar collector captures solar heat and converts it into thermal energy through efficient light concentration and heat absorption technology, providing an initial temperature increase for the supplied water. The collector can automatically adjust the concentration angle according to the intensity of sunlight to maximize heat collection efficiency, raising the initial temperature of the supplied water from ambient temperature to 50-90°C, thus reducing the heat load on the subsequent wet saturated steam preheating module. Furthermore, this module can combine daytime and nighttime grid load fluctuations, operating in conjunction with off-peak electricity and green electricity to provide stable, low-cost clean energy preheating for the water supply system.

[0055] Furthermore, the geothermal preheating module includes a geothermal heat exchanger, arranged in parallel with a concentrating solar collector, to complete the first stage of preheating for the low-temperature water supply. The geothermal heat exchanger, directly connected to a geothermal well, transfers heat from the geothermal fluid to the water supply through a high-efficiency heat exchanger. This module fully utilizes the stable heat supply capacity of geothermal resources, unaffected by weather or time, providing reliable heat input for the low-temperature water supply. During the preheating process, the geothermal heat exchanger and the solar collector operate collaboratively, each undertaking the primary preheating task at different times. For example, during the day, solar energy is the primary source, with geothermal energy serving as an auxiliary heat source; at night and on cloudy days, geothermal energy provides all the heat, ensuring the continuity and stability of the entire water supply system.

[0056] Furthermore, by arranging concentrating solar collectors and geothermal heat exchangers side-by-side and combining them to complete the first stage of preheating, this solution achieves efficient synergy of multiple heat sources. The combined use of solar and geothermal energy not only improves the energy utilization efficiency of the preheating process but also reduces the costs and carbon emissions associated with traditional energy sources (such as electricity and natural gas). Simultaneously, this modular preheating system is highly flexible, allowing for adjustments to the working priority of each module based on seasonal and regional resource differences.

[0057] Preferably, the geothermal heat exchanger is equipped with a three-way valve; the inlet of the three-way valve is used to receive the heating medium of the geothermal heat exchanger; the outlet of the three-way valve is connected to the preheating module and the molten salt heating module respectively; the opening and closing degree of the three-way valve connected to the preheating module and the molten salt heating module is controlled by the control module.

[0058] In this embodiment of the invention, the inlet of the three-way valve is connected to the heating medium of the geothermal heat exchanger, mainly receiving hot fluid (such as geothermal hot water or geothermal steam) from the geothermal well. Through the design of the three-way valve, the heat output from the geothermal heat exchanger can be transferred to the preheating module and the molten salt heating module respectively, achieving efficient utilization and flexible allocation of geothermal resources.

[0059] The three-way valve's outlets are connected to the preheating module and the molten salt heating module, respectively. The valve opening degree at each outlet is dynamically adjusted according to system operating requirements, thereby regulating the geothermal heat flow to different modules. The preheating module is mainly used to heat oilfield produced water, providing stable wet saturated steam for subsequent evaporation units. The molten salt heating module utilizes geothermal heat to supplement the molten salt thermal storage system, providing a continuous heat source for superheated steam production. The three-way valve is connected to a control module for real-time regulation: the control module dynamically adjusts the opening ratio of the three-way valve based on steam injection requirements, current system operating status, and the heating capacity of the geothermal fluid, ensuring the optimal distribution of geothermal heat.

[0060] Preferably, the control module is configured to: construct a corresponding LSTM model based on historical steam injection data, real-time steam demand, and oil well operating parameters to predict future steam injection demand at a predetermined time; determine the preheating demand for low-temperature water supply based on the steam injection demand and the heat exchange efficiency of the evaporator; determine the supplementary heat exchange power of the geothermal energy preheating module for performing low-temperature water supply preheating based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module; generate a control scheme for the valve opening degree of the three-way valve to the preheating module based on the supplementary heat exchange power of the geothermal energy preheating module; and generate a control scheme for the valve opening degree of the three-way valve to the molten salt heating module based on the remaining heat exchange power of the geothermal energy preheating module.

[0061] Furthermore, determining the supplementary heat exchange power of the geothermal preheating module performing low-temperature water supply preheating based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module includes: using a collaborative game theory algorithm, treating the preheating module and the molten salt heating module as game players, and constructing a corresponding objective function to maximize the steam injection demand satisfaction rate and molten salt thermal storage efficiency; and using the Lagrange relaxation method to iteratively solve the objective function to obtain the optimal supplementary heat exchange power of the geothermal preheating module performing low-temperature water supply preheating.

[0062] In this embodiment of the invention, dynamic control of heat distribution between the geothermal preheating module and the molten salt heating module is achieved through prediction algorithms and optimization strategies, ensuring efficient satisfaction of steam injection demand and the overall economic efficiency of system operation. The core functions of the control module mainly include steam injection demand prediction, determination of low-temperature water preheating demand, calculation of the additional heat exchange power to be generated for the geothermal preheating module, and valve control scheme for a three-way valve based on the heat exchange power distribution. Specifically, it includes the following:

[0063] 1) Steam Injection Demand Forecasting: The control module first constructs an LSTM (Long Short-Term Memory) model based on historical steam injection data, real-time steam demand, and well operating parameters to predict steam injection demand at specific future moments. Through deep learning of historical data and real-time parameters, the LSTM model can effectively capture the dynamic changes in steam injection demand. For example, when an oil well enters different recovery stages or the ambient temperature changes, steam injection demand may fluctuate nonlinearly, and the LSTM model can provide accurate predictions in advance based on these changes. This predictive function provides a scientific basis for subsequent preheating demand and geothermal energy allocation, ensuring the system's forward-looking and responsive operation.

[0064] 2) Determination of Low-Temperature Feed Water Preheating Requirements: Based on the predicted steam injection demand and the evaporator's heat exchange efficiency, the control module calculates the preheating requirements for the low-temperature feed water. The evaporator's heat exchange efficiency directly affects the generation capacity of wet saturated steam, while the degree of preheating of the low-temperature feed water determines the evaporator's heat load. By comprehensively considering these factors, the control module can accurately determine the target temperature that the low-temperature feed water needs to reach, thereby meeting the steam injection demand while reducing the risk of scaling within the evaporator and improving overall heat exchange efficiency.

[0065] 3) Calculation of Additional Heat Exchange Power for the Geothermal Preheating Module: The control module further combines the real-time heat exchange power of the wet saturated steam preheating module and the solar preheating module to dynamically calculate the additional heat exchange power required for the geothermal preheating module. The wet saturated steam preheating module recovers heat using wet saturated steam from the evaporator, while the solar preheating module provides a clean heat source through high-efficiency concentrating technology. However, the heat supply from both components fluctuates, especially the solar module, which is significantly affected by weather and diurnal conditions. Therefore, the control module needs to monitor the heat exchange power of these two modules in real time and calculate the portion that fails to meet the required heat exchange power as the additional heat exchange power required for the geothermal preheating module.

[0066] To optimize this allocation process, the control module incorporates a cooperative game theory algorithm, treating the preheating module and the molten salt heating module as players. A corresponding objective function is constructed with the goal of maximizing the steam injection demand satisfaction rate and the molten salt thermal storage efficiency. The introduction of cooperative game theory enables the system to dynamically balance the resource allocation of both modules, ensuring sufficient preheating of the low-temperature water supply while also storing enough heat in the molten salt system for subsequent superheated steam production.

[0067] 4) Optimization of Heat Exchange Power Allocation: The control module uses the Lagrange relaxation method to iteratively solve the objective function, obtaining the optimal supplementary heat exchange power for the geothermal preheating module. The Lagrange relaxation method is a mathematical tool suitable for solving complex constrained optimization problems. By introducing relaxation variables, the original objective function is decomposed into easily solvable subproblems, thus approximating the global optimum in multiple iterations. This method can accurately calculate the supplementary power required by the geothermal preheating module, ensuring the economy and effectiveness of resource allocation.

[0068] 5) Three-way valve control scheme generation: Based on the supplementary heat exchange power of the geothermal preheating module, the control module generates a control scheme for the opening and closing degree of the three-way valve leading to the preheating module. Simultaneously, based on the remaining heat exchange power of the geothermal preheating module, a control scheme for the opening and closing degree of the three-way valve leading to the molten salt heating module is generated. The dynamic regulation of the three-way valve is executed in real time by the control module to ensure the rational allocation of geothermal resources among different modules. The preheating module prioritizes meeting the preheating needs of the low-temperature water supply, while the molten salt heating module utilizes the remaining geothermal energy for heat storage, providing a supplementary heat source for the production of superheated steam.

[0069] Based on the present invention, the control module can capture dynamic changes in steam injection demand in advance through the predictive function of the LSTM model, making the system operation more intelligent and precise, and effectively reducing heat waste and insufficient heating. The introduction of the cooperative game theory algorithm ensures the optimal allocation of geothermal resources between the preheating module and the molten salt heating module, satisfying the current steam injection demand while providing reserve heat for subsequent steam production. The optimization solution of the Lagrange relaxation method makes the heat exchange power allocation more efficient, thereby reducing the excessive consumption of geothermal resources and other energy sources and lowering the system's operating costs. Through the dynamic control of the three-way valve, the control module can adapt to fluctuations in steam injection demand and heat exchange module performance in real time, ensuring stable operation of the system under various operating conditions. Combining the clean heat sources of wet saturated steam and the solar preheating module, the control module minimizes dependence on traditional energy sources and improves the system's environmental friendliness.

[0070] Specifically, the objective function is expressed as:

[0071]

[0072] in, and Preset weighting factors that respectively represent the importance of produced water preheating requirements and molten salt thermal storage requirements; Geothermal heat supply allocated for preheating extracted water; Total preheating requirements for produced water; For the geothermal heat supplied to molten salt heating; The target requirement for heating molten salt.

[0073] Preferably, the evaporation device includes multiple heat exchangers; each heat exchanger is connected in series via pipes, with the water inlet of the first heat exchanger connected to the water outlet of the water supply device, and the water outlet of the last heat exchanger being the outlet of the wet saturated steam; the molten salt flow pipe flows from the last heat exchanger to the first heat exchanger, and then flows back from the first heat exchanger to the molten salt heating module.

[0074] In this embodiment of the invention, the evaporation device consists of multiple heat exchangers connected in series via pipes, forming a highly efficient staged heating and evaporation system. The inlet of the first heat exchanger is connected to the outlet of a water supply device, which provides preheated, low-temperature water that begins primary heating upon entering the first heat exchanger. Through the sequential action of multiple heat exchangers, the water temperature gradually increases, approaching saturation, until the last heat exchanger heats the water to a wet saturated steam state, completing the evaporation process. The final wet saturated steam is then transported through the outlet to a subsequent steam-water separator or superheater to meet the needs of the steam injection system. To ensure heat exchange efficiency and full utilization of molten salt heat, the evaporation device is equipped with a molten salt flow pipe. This pipe flows from the last heat exchanger to the first, creating a highly efficient heat gradient within the evaporation device through a reverse heat transfer mechanism. The molten salt cools down from the last heat exchanger, gradually transferring heat to the preceding heat exchangers, ensuring maximum utilization of thermal energy within the system. Finally, the molten salt flows back from the first heat exchanger to the molten salt heating module, is reheated, and is recycled.

[0075] Preferably, the superheated steam generating device includes: a steam-water separator for separating the incoming wet saturated steam into dry steam and saturated water respectively; the dry steam and saturated water output from the steam-water separator are connected to a superheater and a mixer respectively through a dry steam pipe and a separated water pipe; the superheater performs heat exchange with a molten salt flow pipe to convert the dry steam into superheated steam.

[0076] Furthermore, the superheater is connected to another inlet of the mixer via a first superheated steam pipeline to collect superheated steam into the mixer; the mixer is used to perform superheated steam and saturated water mixing based on the gas injection requirements to obtain superheated steam that meets the gas injection requirements, and outputs the superheated steam to the steam injection well via a second superheated steam pipeline.

[0077] In this embodiment of the invention, the superheated steam generator, through a combination of a steam-water separator, a superheater, and a mixer, achieves precise conversion of wet saturated steam into superheated steam that meets the steam injection requirements, providing efficient and stable steam output for the steam injection well. The steam-water separator is one of the core components of the entire device, responsible for separating the wet saturated steam from the water. During the separation process, the wet saturated steam is separated into dry steam and saturated water based on the density difference between steam and liquid water. This process not only improves the steam quality but also provides a suitable working fluid for subsequent superheating and mixing processes. The dry steam output from the steam-water separator is transported to the superheater for further heating via a dry steam pipeline, while the separated saturated water is transported to the mixer via a separated water pipeline, ready to be mixed with the superheated steam.

[0078] Furthermore, the superheater heats the dry steam to a high superheat state through heat exchange with the molten salt flow pipe, thereby generating high-quality superheated steam. The molten salt flow pipe, acting as a heat source, utilizes the stable heat supply from the high-temperature molten salt to achieve efficient heating of the dry steam. This design not only ensures that the temperature of the superheated steam meets the requirements of the injection well but also effectively reduces energy consumption. The superheated steam output from the superheater is transported to the mixer through the first superheated steam pipe, where it is mixed with saturated water transported through the separation water pipe in the required proportion. The mixer's function is to precisely mix the high-superheated steam and saturated water in a precise proportion according to real-time injection requirements, generating target superheated steam that meets downhole conditions. By adjusting the mixing ratio of superheated steam and saturated water, the temperature and pressure of the mixed steam can be precisely controlled, ensuring the efficiency and stability of the injection process. The generated target superheated steam is transported to the injection well through the second superheated steam pipe, providing the necessary thermal energy support for heavy oil extraction.

[0079] Preferably, the control module is configured to: construct corresponding heat balance models and flow balance models based on the state information of superheated steam and saturated water entering the mixer; determine the mixing ratio of superheated steam and saturated water based on the heat balance models and flow balance models; and adjust the valve opening of the mixer in real time according to the mixing ratio.

[0080] Specifically, the heat balance model is expressed as:

[0081]

[0082] The flow balance model is expressed as follows:

[0083]

[0084] in, , and These are the mass flow rates of the mixed steam, the superheated steam, and the saturated water, respectively. , and These are the specific enthalpy of mixed steam, the specific enthalpy of superheated steam, and the specific enthalpy of saturated water, respectively.

[0085] Furthermore, the mixing ratio of superheated steam and saturated water is determined based on the heat balance model and the flow balance model, including: performing a joint solution based on the heat balance model and the flow balance model to obtain the flow ratio of superheated steam and saturated water, so as to determine the mixing ratio of superheated steam and saturated water.

[0086] In this embodiment of the invention, the control module is configured to construct corresponding heat balance and flow balance models based on the real-time status information of the superheated steam and saturated water fed into the mixer, thereby achieving dynamic control of the mixing ratio of superheated steam and saturated water. The heat balance model is used to calculate the energy distribution of the mixed steam, ensuring that the temperature and pressure of the output steam meet the steam injection requirements, while the flow balance model is used to determine the mass flow rate ratio of superheated steam and saturated water during the mixing process, ensuring the accuracy of the total steam flow rate. Based on these two models, the control module can adjust the opening and closing degree of the valves in the mixer in real time, thereby dynamically achieving optimal mixing of superheated steam and saturated water.

[0087] In the heat balance model, the system calculates the energy composition of the mixed steam by monitoring the enthalpy (i.e., heat per unit mass) of the mixed steam, superheated steam, and saturated water. The goal of the heat balance model is to ensure that the enthalpy of the mixed steam matches the steam injection demand, thereby meeting the oil well's requirements for steam temperature. This model fully considers the initial states of the superheated steam and saturated water (such as temperature, pressure, and enthalpy) and dynamically updates its parameters to adapt to real-time changes in steam injection demand.

[0088] The flow balance model is used to ensure the material conservation of the system. By accurately calculating the total flow rate of the mixed steam and combining it with the heat balance model, the flow ratio of superheated steam and saturated water is further determined. The core of this model is to ensure that the total flow rate of the mixed steam is consistent with the steam injection demand, while avoiding the overuse of superheated steam or saturated water and optimizing resource utilization efficiency.

[0089] Based on the heat balance model and the flow balance model, the control module can dynamically determine the mixing ratio of superheated steam and saturated water through joint solution. Specifically, the control module monitors the state parameters of the superheated steam and saturated water input to the mixer in real time, and calculates the required mixing ratio based on the steam injection demand. Subsequently, it adjusts the opening and closing degree of the valves in each channel of the mixer according to the calculation results to ensure that the temperature, pressure, and flow rate of the mixed steam are consistent with the target values.

[0090] Preferably, after adjusting the valve opening of the mixer in real time according to the mixing ratio, the control device is further configured to: collect the state parameters of the superheated steam required for steam injection in real time, and identify the deviation value between the superheated steam and the state parameters of the target superheated steam; and execute a PID control algorithm based on the deviation value to correct the valve opening of the mixing device, so as to keep the deviation value between the actual superheated steam state parameters and the target superheated steam state parameters within a preset difference threshold range.

[0091] In this embodiment of the invention, after initial valve opening adjustment based on the mixing ratio, the control device further optimizes the control process by real-time monitoring of the superheated steam state parameters required for steam injection and identifying the deviation between the actual superheated steam state parameters and the target superheated steam state parameters. To achieve this, the control device introduces a PID (Proportional-Integral-Derivative) control algorithm to dynamically correct the valve opening of the mixer, ensuring that the actual output superheated steam state always remains consistent with the target requirements.

[0092] Specifically, the control unit first collects key state parameters of the superheated steam output during the steam injection process in real time through a sensor network, such as temperature, pressure, and flow rate. These parameters directly affect the thermal efficiency and oil recovery effect of downhole steam injection, making their accuracy crucial. Simultaneously, the control unit presets the parameter range for the target superheated steam, defining these parameter values ​​based on downhole requirements and real-time adjusted injection targets. Subsequently, the control unit calculates the deviation between the actual and target parameters, identifying issues such as insufficient temperature, pressure deviation, or unstable flow rate. Once a deviation exceeds a preset threshold, the control unit immediately activates the PID control algorithm. The PID algorithm uses proportional control to quickly respond to large deviations, integral control to eliminate accumulated errors, and derivative control to suppress rapid system fluctuations, resulting in smoother and more precise control adjustments. Based on the PID algorithm's calculations, the control unit further optimizes the opening of each valve within the mixer, including adjusting the flow rate ratio between the superheated steam channel and the saturated water channel, thereby gradually eliminating deviations.

[0093] The dynamic correction function of PID control can adapt to changes in steam injection demand under complex operating conditions. For example, when downhole steam injection demand fluctuates due to changes in the external environment or well conditions, PID control can quickly adjust within milliseconds to ensure that the temperature, pressure, and flow rate of the output steam always meet the requirements. In addition, PID control effectively avoids the over-adjustment or lag problems that may occur in traditional fixed proportional control through real-time feedback adjustment.

[0094] In one possible implementation, such as Figure 2This paper provides a schematic diagram of a molten salt heating superheated steam generation system. For ease of explanation of the system's operation, the water supply device only preheats the steam. The system consists of a preheated water pipe 1 (water supply device), an evaporator 2 (evaporator), an extraction steam pipe 3, a first wet steam pipe 4, a second wet steam pipe 5, a second hot salt pipe 6, a steam-water separator 7 (superheated steam generation device), a separated water pipe 8, a dry steam pipe 9, a superheater 10, a first superheated steam pipe 11, a mixer 12, a second superheated steam pipe 13, a first hot salt pipe 14, a cold salt pipe 15, a preheater 16, an oilfield produced water supply pipe 17, and a condensate pipe 18.

[0095] The working principles and processes of each part of the system are as follows, in conjunction with the embodiments.

[0096] 1. The main equipment of this invention consists of a preheater 16, an evaporator 2, a steam-water separator 7, a superheater 10, and a mixer 12.

[0097] 2. Oilfield produced water is connected to preheater 16 through oilfield produced water supply pipeline 17. After being heated in preheater 16, the oilfield produced water is connected to evaporator 2 through preheated water pipeline 1. Taking binary molten salt as an example, the freezing point of binary molten salt is 220℃, the oilfield produced water supply temperature is 40-70℃, and the preheated water temperature is 230-250℃. The silicon content of oilfield produced water can be <250mg / L.

[0098] 3. Evaporator 2 can consist of one or more heat exchangers; if intermediate adjustment is not considered, the evaporator can be equipped with only one heat exchanger, and if intermediate adjustment is considered, the evaporator can be equipped with two or more heat exchangers.

[0099] 4. The produced water from the oilfield is heated by molten salt in the evaporator 2 to become wet saturated steam. The wet saturated steam is transported out through the first wet steam pipeline 4. Part of the wet saturated steam is connected to the preheater 16 through the extraction steam pipeline 3 to heat the produced water in the preheater. The other part of the wet saturated steam is connected to the steam-water separator 7 through the second wet steam pipeline 5. The parameters of the wet saturated steam produced by the evaporator can be 8MPa, 295℃, and dryness 75%.

[0100] 5. The wet saturated steam heated by the oilfield produced water in the preheater 16 releases heat and turns into condensate in the preheater 16; the condensate temperature is below 80℃.

[0101] 6. The wet saturated steam connected to the steam-water separator 7 is partially converted into dry steam and partially into saturated water. The dry steam parameters can be 99%-100% dryness, 75% dry steam mass, and 25% saturated water mass.

[0102] 7. The saturated water separated from the steam-water separator 7 is connected to the mixer 12 via the separated water pipe 8.

[0103] 8. The dry steam separated from the steam-water separator 7 is connected to the superheater 10 via the dry steam pipe 9. In the superheater 10, the dry steam is heated by high-temperature molten salt to become superheated steam with a high degree of superheat; the superheat of the superheated steam with a high degree of superheat can be 135℃.

[0104] 9. The superheated steam with high superheat generated in the superheater 10 is connected to the mixer 12 via the first superheated steam pipe 11.

[0105] 10. In the mixer 12, high-superheated superheated steam and saturated water are mixed to become low-superheated superheated steam, which is then transported to the steam injection well through the second superheated steam pipeline 13; the superheat of the low-superheated superheated steam can be 15-20℃.

[0106] 11. Molten salt serves as the heat source medium for the system. High-temperature molten salt is connected to the superheater 10 via the first hot salt pipe 14 to heat dry steam into superheated steam with a high degree of superheat. Then, it is connected to the evaporator 2 via the second hot salt pipe 6 to heat preheated water into wet saturated steam. Finally, it is discharged from the system via the cold salt pipe 15. Taking binary molten salt as an example, the high-temperature molten salt temperature can be 560℃, and the low-temperature molten salt temperature after heat exchange can be 285℃.

[0107] Figure 3 This is a flowchart of a method for controlling a molten salt heating superheated steam generation system according to one embodiment of the present invention. Figure 3 As shown, an embodiment of the present invention provides a control method for a molten salt heating superheated steam generation system, the method comprising:

[0108] Step S10: Collect real-time steam injection demand information, and perform target operation state simulations for the water supply device, evaporation device, and superheated steam generator based on the steam injection demand information;

[0109] Step S20: Based on the deviation between the real-time operating status of the water supply device, the evaporation device, and the superheated steam generator and the corresponding target operating status, generate control schemes for the water supply device, the evaporation device, and the superheated steam generator respectively.

[0110] Step S30: Execute the control scheme to adjust the status of the water supply device, evaporation device and superheated steam generator respectively.

[0111] Preferably, the water supply device includes: an oilfield produced water supply pipeline for inputting oilfield produced water as low-temperature water for the water supply device; a preheating module connected to the oilfield produced water supply pipeline for preheating the low-temperature water; and the preheating module connected to an evaporation device via a pipeline for transmitting the preheated low-temperature water to the evaporation device.

[0112] Preferably, the preheating module includes: a wet saturated steam preheating module, a solar preheating module, and a geothermal preheating module, combined for preheating the low-temperature supplied water; the wet saturated steam in the wet saturated steam preheating module is obtained by separating the wet saturated steam output from the evaporator and flows into the wet saturated steam preheating module via a first wet steam pipeline; another portion of the wet saturated steam output from the evaporator flows into the evaporator via a second wet steam pipeline; the solar preheating module includes: a concentrating solar collector, installed between the wet saturated steam preheating module and the oilfield produced water. Between the water supply pipes, a first-stage preheating is performed on the low-temperature supply water; the geothermal energy preheating module includes: a geothermal heat exchanger, arranged in parallel with the concentrating solar collector, which, in combination with the concentrating solar collector, performs the first-stage preheating on the low-temperature supply water; the geothermal heat exchanger is equipped with a three-way valve; the inlet of the three-way valve is used to receive the heating medium of the geothermal heat exchanger; the outlet of the three-way valve is respectively connected to the preheating module and the molten salt heating module; the opening and closing degree of the three-way valve connected to the preheating module and the molten salt heating module is controlled by the control module.

[0113] Preferably, the generation rule for the control scheme of the preheating module is as follows: based on historical steam injection data, real-time steam demand, and oil well operating parameters, a corresponding LSTM model is constructed to predict the steam injection demand at a predetermined time in the future; based on the steam injection demand and the heat exchange efficiency of the evaporator, the preheating demand for low-temperature water supply is determined; based on the heat exchange power of the real-time wet saturated steam preheating module and the solar preheating module, the supplementary heat exchange power of the geothermal energy preheating module for performing low-temperature water supply preheating is determined; based on the supplementary heat exchange power of the geothermal energy preheating module, a control scheme for the valve opening degree of the three-way valve to the preheating module is generated, and based on the remaining heat exchange power of the geothermal energy preheating module, a control scheme for the valve opening degree of the three-way valve to the molten salt heating module is generated, which serves as the control scheme for the preheating module.

[0114] The present invention also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the above-described control method for a molten salt heating superheated steam generation system.

[0115] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0116] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details described above. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not further describe the various possible combinations.

[0117] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the embodiments of the present invention, they should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. A molten salt heated superheated steam generating system, characterized by, The system comprises: sequentially connected water supply device, evaporation device and superheated steam generation device; a molten salt overflow pipeline is arranged from the superheated steam generation device to the evaporation device, for providing heat source to the superheated steam generation device and the evaporation device; the water supply device is used for preheating low-temperature supply water and transmitting the preheated low-temperature supply water to the evaporation device, so that the evaporation device converts the preheated low-temperature supply water into wet saturated steam; the superheated steam generation device is used for converting the wet saturated steam into superheated steam meeting steam injection requirements; a control device is used for controlling the running states of the water supply device, the evaporation device and the superheated steam generation device based on steam injection requirements; wherein the superheated steam generation device comprises a steam-water separator, which is used for separating the wet saturated steam into dry steam and saturated water; the dry steam and the saturated water output by the steam-water separator are respectively connected to a superheater and a mixer through a dry steam pipeline and a separated water pipeline; the superheater exchanges heat with the molten salt overflow pipeline to convert the dry steam into superheated steam; the superheater is connected to another inlet of the mixer through a first superheated steam pipeline to make the superheated steam flow into the mixer; the mixer is used for mixing the superheated steam and the saturated water based on steam injection requirements to obtain superheated steam meeting the steam injection requirements, and the superheated steam is output to a steam injection well through a second superheated steam pipeline; the control device is configured to: construct a corresponding heat balance model and a flow balance model based on the state information of the superheated steam and the saturated water flowing into the mixer; determine the mixing ratio of the superheated steam and the saturated water based on the heat balance model and the flow balance model; and adjust the valve opening degree of the mixer in real time according to the mixing ratio; the heat balance model is expressed as: the flow balance model is expressed as: wherein, , and are the mass flow rate of mixed steam, the mass flow rate of superheated steam and the mass flow rate of saturated water, respectively; , and are the specific enthalpy of mixed steam, the specific enthalpy of superheated steam and the specific enthalpy of saturated water, respectively.

2. The system of claim 1, wherein, the water supply device comprises: an oilfield produced water feed pipeline, which is used for inputting oilfield produced water as low-temperature supply water of the water supply device; a preheating module, which is connected to the oilfield produced water feed pipeline and is used for preheating the low-temperature supply water; the preheating module is connected to the evaporation device through a pipeline to transmit the preheated low-temperature supply water to the evaporation device.

3. The system of claim 2, wherein, the preheating module comprises: a wet saturated steam preheating module, a solar preheating module and a geothermal energy preheating module, which are combined to preheat the low-temperature supply water; wet saturated steam of the wet saturated steam preheating module is separated from the wet saturated steam output by the evaporation device and flows into the wet saturated steam preheating module based on a first wet steam pipeline; another part of the wet saturated steam output by the evaporation device flows into the evaporation device based on a second wet steam pipeline.

4. The system of claim 3, wherein, the solar preheating module comprises: a concentrating solar collector, which is arranged between the wet saturated steam preheating module and the oilfield produced water feed pipeline and is used for preheating the low-temperature supply water in the first stage; the geothermal energy preheating module comprises: a geothermal heat exchanger, which is arranged in parallel with the concentrating solar collector and is combined with the concentrating solar collector to preheat the low-temperature supply water in the first stage.

5. The system of claim 4, wherein, the geothermal heat exchanger is provided with a three-way valve; a water inlet of the three-way valve is used for flowing in heating medium of the geothermal heat exchanger; The water outlet of the three-way valve is connected to the preheating module and the molten salt heating module, respectively; The opening degree of the valve of the three-way valve connected to the preheating module and the molten salt heating module is controlled based on the control device.

6. The system of claim 5, wherein, The control device is configured to: Based on historical steam injection data, real-time steam demand and oil well operating parameters, a corresponding LSTM model is constructed to predict the steam injection demand at a future predetermined time; Based on the steam injection demand and the heat exchange efficiency of the evaporator, the low-temperature feed water preheating demand determination is performed; Based on the real-time wet saturated steam preheating module and the heat exchange power of the solar preheating module, the heat exchange power to be supplemented of the geothermal energy preheating module for performing low-temperature feed water preheating is determined; Based on the heat exchange power to be supplemented of the geothermal energy preheating module, a control scheme for the opening degree of the valve of the three-way valve connected to the preheating module is generated, and based on the remaining heat exchange power of the geothermal energy preheating module, a control scheme for the opening degree of the valve of the three-way valve connected to the molten salt heating module is generated.

7. The system of claim 6, wherein, The determination of the heat exchange power to be supplemented of the geothermal energy preheating module for performing low-temperature feed water preheating based on the real-time wet saturated steam preheating module and the heat exchange power of the solar preheating module includes: Based on the cooperative game theory algorithm, the preheating module and the molten salt heating module are regarded as game parties to maximize the steam injection demand satisfaction rate and the molten salt heat storage efficiency to construct a corresponding objective function; Based on the Lagrange relaxation method, the objective function is iteratively solved to obtain the optimal heat exchange power to be supplemented of the geothermal energy preheating module for performing low-temperature feed water preheating.

8. The system of claim 7, wherein, The objective function is expressed as: wherein, and respectively represent preset weight factors of the importance of the produced water preheating requirement and the molten salt heat storage requirement. Qg = geothermal heat supply assigned to produced water preheating; total produced water preheat requirement; Qh is the amount of geothermal heat supplied to the molten salt heating; The need for target heating of molten salts.

9. The system of claim 1, wherein, The evaporating device includes a plurality of heat exchangers; Each heat exchange is connected in series through a pipeline, the water outlet of the water supply device is connected to the water inlet of the first heat exchanger, and the water outlet of the last heat exchange is the output port of the wet saturated steam; The molten salt overflow pipeline flows from the last heat exchanger to the first heat exchanger, and returns to the molten salt heating module from the first heat exchanger.

10. The system of claim 1, wherein, The determination of the mixing ratio of superheated steam and saturated water based on the heat balance model and the flow balance model includes: Based on the heat balance model and the flow balance model, a joint solution is performed to obtain the flow ratio of superheated steam and saturated water to determine the mixing ratio of superheated steam and saturated water.

11. The system of claim 1, wherein, After real-time regulation of the valve opening degree of the mixer according to the mixing ratio, the control device is further configured to: Real-time acquisition of the state parameters of the superheated steam of the steam injection demand, and identification of the deviation value between the state parameters of the actual superheated steam and the target superheated steam; Based on the deviation value, a PID control algorithm is executed to correct the valve opening degree of the mixing device, so that the deviation value between the state parameters of the actual superheated steam and the target superheated steam is kept within a preset deviation threshold range.

12. A molten salt heated superheated steam generating system control method characterized by, The method is applied to the molten salt heating superheated steam generation system of any one of claims 1-11, and the method includes: Collecting real-time steam injection demand information, and based on the steam injection demand information, simulating the target operating state of the water supply device, the evaporating device and the superheated steam generation device, respectively; Based on the deviation value between the real-time operating state and the corresponding target operating state of the water supply device, the evaporating device and the superheated steam generation device, respectively, generating a control scheme for the water supply device, the evaporating device and the superheated steam generation device; The control scheme is executed to adjust the states of the water supply device, the evaporation device, and the superheated steam generation device, respectively.

13. The method of claim 12, wherein, The water supply device comprises: a produced water feed pipe for inputting produced water as low-temperature feed water of the water supply device; a preheating module connected with the produced water feed pipe for performing preheating on the low-temperature feed water; The preheating module is connected with the evaporation device through a pipe for transmitting the preheated low-temperature feed water to the evaporation device.

14. The method of claim 13, wherein, The preheating module comprises: a wet saturated steam preheating module, a solar energy preheating module, and a geothermal energy preheating module, which are combined to perform preheating on the low-temperature feed water; The wet saturated steam of the wet saturated steam preheating module is separated from the wet saturated steam output by the evaporation device and is introduced into the wet saturated steam preheating module based on a first wet steam pipe; Another part of the wet saturated steam output by the evaporation device is introduced into the evaporation device based on a second wet steam pipe; The solar energy preheating module comprises: a concentrating solar collector arranged between the wet saturated steam preheating module and the produced water feed pipe for performing first-stage preheating on the low-temperature feed water; The geothermal energy preheating module comprises: a geothermal heat exchanger arranged in parallel with the concentrating solar collector and combined with the concentrating solar collector to perform first-stage preheating on the low-temperature feed water; The geothermal heat exchanger is provided with a three-way valve; The water inlet of the three-way valve is used to introduce the heating medium of the geothermal heat exchanger; The water outlets of the three-way valve lead to the preheating module and the molten salt heating module, respectively; The opening and closing degrees of the valves of the three-way valve leading to the preheating module and the molten salt heating module are controlled based on the control module.

15. The method of claim 14, wherein, The generation rule of the control scheme of the preheating module is: Based on historical steam injection data, real-time steam demand, and oil well operation parameters, a corresponding LSTM model is constructed to predict the steam injection demand at a future predetermined time; Based on the steam injection demand and the heat exchange efficiency of the evaporator, the low-temperature feed water preheating demand determination is performed; Based on the real-time heat exchange power of the wet saturated steam preheating module and the solar energy preheating module, the to-be-supplemented heat exchange power of the geothermal energy preheating module for performing preheating on the low-temperature feed water is determined; Based on the to-be-supplemented heat exchange power of the geothermal energy preheating module, the control scheme of the opening and closing degree of the valve of the three-way valve leading to the preheating module is generated, and based on the remaining heat exchange power of the geothermal energy preheating module, the control scheme of the opening and closing degree of the valve of the three-way valve leading to the molten salt heating module is generated as the control scheme of the preheating module.

16. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions which, when executed on a computer, cause the computer to perform the molten salt heating superheated steam generation system control method of any one of claims 12-15.

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