Steam system, thickened oil SAGD (Steam Assisted Gravity Drainage) exploitation system and superheated steam control method

Abstract

The invention discloses a steam system, a thickened oil SAGD exploitation system and a superheated steam control method, and belongs to the technical field of thickened oil exploitation, and the steam system comprises a first steam generation subsystem, a second steam generation subsystem, a steam injection subsystem and an operation control subsystem; the first steam generation subsystem comprises a heat absorber for gathering solar radiation energy and generates first superheated steam; the second steam generation subsystem comprises a steam injection boiler for generating second superheated steam; the steam injection subsystem comprises a steam injection well and an underground steam cavity, and the steam injection well is used for injecting superheated steam into the underground steam cavity; the underground steam cavity is used for storing and releasing superheated steam to an oil storage layer; the operation control subsystem is used for periodically calculating a superheated steam difference value and correspondingly sending an opening or closing signal to the second steam generation subsystem according to the superheated steam difference value, and the superheated steam production system which is low in cost, stable in superheated steam yield and rapid in dynamic response is provided for clean and efficient exploitation of thick oil.

Description

Technical Field

[0001] The present invention relates to the field of heavy oil production, and in particular to a steam system, a heavy oil SAGD production system and a superheated steam control method. Background Art

[0002] As an important petroleum resource, heavy oil has high industrial application and national defense strategic value. Heavy oil has high viscosity and large flow resistance in the oil layer, and it is difficult to develop it economically and efficiently using conventional technology. The viscosity of heavy oil is very sensitive to temperature. As the temperature rises, the viscosity of heavy oil will drop sharply. At present, the most commonly used method for heavy oil development is steam injection thermal recovery, which mainly includes steam stimulation, steam flooding and steam-assisted gravity drainage (SAGD). In the steam-assisted gravity drainage (SAGD) technology, superheated steam needs to be injected into the heavy oil reservoir to heat the oil reservoir using the latent heat of vaporization of the superheated steam. According to statistics, in the steam-assisted gravity drainage (SAGD) production, the energy consumption of the superheated steam production system accounts for more than 90% of the total energy consumption of heavy oil production. In order to achieve clean heating for heavy oil production, there is currently a solar steam production system to assist in heavy oil thermal recovery. In order to overcome the shortcomings of discontinuous and unstable solar energy, a "heat storage tank system" is set up on the ground to store heat as much as possible when the solar radiation intensity is high. When the solar radiation intensity is low or there is no solar radiation, the heat in the heat storage tank is used to heat the heavy oil reservoir. Summary of the invention

[0003] The present application provides a steam system, a heavy oil SAGD production system and a superheated steam control method, which can fully utilize solar energy and ensure the needs of heavy oil development and production at a low cost, and provide a superheated steam production system with stable superheated steam output and rapid dynamic response for the clean and efficient production of heavy oil.

[0004] On the one hand, an embodiment of the present application provides a steam system, which is applied to a heavy oil SAGD production system, wherein the steam system comprises: a first steam generation subsystem, a second steam generation subsystem, a steam injection subsystem, and an operation control subsystem;

[0005] The first steam generation subsystem includes a heat absorber, which is used to collect solar radiation energy and heat the first water working medium inside the heat absorber to generate first superheated steam, and input it into the steam injection subsystem;

[0006] The second steam generating subsystem comprises a steam injection boiler, which is used to heat the second water working medium inside the steam generating subsystem to generate second superheated steam when the second steam generating subsystem is turned on, and input the second superheated steam into the steam injection subsystem;

[0007] The steam injection subsystem comprises a steam injection well and an underground steam chamber, wherein the steam injection well is used to inject the input superheated steam into the underground steam chamber; the underground steam chamber is located above the oil reservoir, and is used to store the superheated steam and release the superheated steam to the oil reservoir, so that the heated heavy oil in the oil reservoir is transported to the production well by steam driving force and gravity driving force; the superheated steam comprises the first superheated steam and / or the second superheated steam;

[0008] The operation control subsystem is used to periodically calculate the superheated steam difference based on the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the first superheated steam amount, and send an opening or closing signal to the second steam generating subsystem accordingly according to the calculated superheated steam difference.

[0009] Optionally, the operation control subsystem is used to periodically calculate the superheated steam difference according to the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the amount of the first superheated steam, including:

[0010] The operation control subsystem calculates the required superheated steam amount of the heavy oil SAGD production system according to the preset heavy oil production amount of the production well;

[0011] The operation control subsystem periodically calculates the existing superheated steam amount, and calculates the superheated steam difference based on the required superheated steam amount; wherein the existing superheated steam amount is the sum of the first superheated steam amount and the superheated steam storage amount of the current cycle, and the superheated steam difference is the difference between the required superheated steam amount and the existing superheated steam amount.

[0012] Optionally, sending an opening or closing signal to the second steam generating subsystem according to the calculated superheated steam difference includes:

[0013] The operation control subsystem sends an opening signal to the second steam generating subsystem when the superheated steam difference is greater than zero;

[0014] After the second steam generating subsystem is turned on, the operation control subsystem uses the superheated steam difference as the demand for the second superheated steam, and accordingly sets the power of the steam injection boiler according to the demand for the second superheated steam.

[0015] Optionally, sending an on or off signal to the second steam generating subsystem according to the calculated superheated steam difference value also includes:

[0016] The operation control subsystem sends a shutdown signal to the second steam generating subsystem when the superheated steam difference is less than or equal to zero;

[0017] When the superheated steam difference is less than zero, the operation control subsystem uses the absolute value of the superheated steam difference as the excess superheated steam amount, and correspondingly uses the excess superheated steam amount as the superheated steam storage amount for the next cycle.

[0018] Optionally, the steam injection subsystem further includes a first steam pipeline, a second steam pipeline, a steam injection main pipe, a first one-way valve and a second one-way valve;

[0019] The first steam pipeline is used to connect the heat absorber and the steam injection main pipe, the first one-way valve is arranged on the first steam pipeline, and the first steam pipeline inputs the first superheated steam generated into the steam injection main pipe when the first one-way valve is opened;

[0020] The second steam pipeline is used to connect the steam injection boiler and the steam injection main pipe, the second one-way valve is arranged on the second steam pipeline, and the second steam pipeline inputs the second superheated steam generated into the steam injection main pipe when the second one-way valve is opened;

[0021] The steam injection mother pipe is connected to the steam injection well and is used to inject the first superheated steam and / or the second superheated steam into the steam injection well.

[0022] Optionally, the first steam generation subsystem further includes a heliostat, a first water pump, a first deaerator, a heat absorption tower and a first superheated steam detector;

[0023] The heliostat is used to reflect and focus sunlight onto the absorber;

[0024] The first deaerator is used to access and process the first softened water provided by the softening equipment, and remove the first gas in the first softened water, wherein the first gas includes dissolved oxygen;

[0025] The first water pump is connected to the first deaerator and the heat absorber, and is used to inject the first softened water treated by the first deaerator into the heat absorber as the first water working medium;

[0026] The heat absorber is arranged at the top of the heat absorption tower;

[0027] The first superheated steam detector is disposed on the first steam pipe, and is used to detect the amount of the first superheated steam generated by the heat absorber.

[0028] Optionally, the second steam generating subsystem further includes a second water pump, a second deaerator and a second superheated steam detector;

[0029] The second deaerator is used to access and process the second softened water provided by the softening equipment, and remove the second gas in the second softened water, wherein the second gas includes dissolved oxygen;

[0030] The second water pump is connected to the second deaerator and the steam injection boiler, and is used to inject the second softened water treated by the second deaerator into the steam injection boiler as the second water working medium;

[0031] The second superheated steam detector is disposed on the second steam pipe and is used to detect the amount of the second superheated steam generated by the steam injection boiler.

[0032] On the other hand, an embodiment of the present application further provides a heavy oil SAGD production system, including a production well and the steam system described in the above embodiment;

[0033] The production well is a horizontal well, whose horizontal section is located in the oil reservoir containing heavy oil and is parallel to the horizontal section of the steam injection well in the steam system, and the horizontal section of the production well is located below the horizontal section of the steam injection well.

[0034] On the other hand, the embodiment of the present application further provides a heavy oil SAGD superheated steam control method, which is applied to the operation control subsystem in the steam system described in the above embodiment, comprising:

[0035] periodically acquiring the amount of first superheated steam detected by the first superheated steam detector and the amount of superheated steam stored in the underground steam chamber in the current cycle;

[0036] calculating a superheated steam difference according to a required superheated steam amount, the superheated steam storage amount of the current cycle, and the amount of the first superheated steam;

[0037] An opening or closing signal is sent to the second steam generating subsystem according to the superheated steam difference.

[0038] Optionally, the generating an on or off signal to the second steam generating subsystem according to the superheated steam difference includes:

[0039] When the superheated steam difference is greater than zero, sending an opening signal to the second steam generating subsystem;

[0040] taking the superheated steam difference as the demand for the second superheated steam, and setting the power of the steam injection boiler accordingly according to the demand for the second superheated steam;

[0041] Alternatively, when the superheated steam difference is less than or equal to zero, sending a shutdown signal to the second steam generating subsystem;

[0042] When the superheated steam difference is less than zero, the absolute value of the superheated steam difference is used as the excess superheated steam amount, and correspondingly the excess superheated steam amount is used as the superheated steam storage amount for the next cycle.

[0043] Compared with the related art, the steam system, heavy oil SAGD production system and superheated steam control method of the embodiments of the present application make full use of the underground steam chamber formed in the heavy oil SAGD production process to store and release superheated steam, which can not only make full use of solar energy, but also smooth the fluctuation of superheated steam amount caused by unstable solar energy. The control algorithm of the operation control subsystem is simple and the dynamic regulation process is fast, which provides a superheated steam production system with low cost, stable superheated steam output and rapid dynamic response for the clean and efficient production of heavy oil.

[0044] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0046] Figure 1 is a schematic diagram of a steam system and a heavy oil SAGD production system in an embodiment of the present application,

[0047] Figure 2 It is a flow chart of the heavy oil SAGD superheated steam control method according to an embodiment of the present application.

[0048] The reference numerals are as follows:

[0049] 11 heat absorber, 12 heliostat, 13 first water pump, 14 first deaerator, 15 heat absorption tower, 16 first superheated steam detector, 21 steam injection boiler, 22 second water pump, 23 second deaerator, 24 second superheated steam detector, 31 steam injection well, 32 underground steam chamber, 33 first steam pipeline, 34 second steam pipeline, 35 steam injection main pipe, 36 first one-way valve, 37 second one-way valve, 4 operation control subsystem, 5 oil reservoir, 6 production well. DETAILED DESCRIPTION

[0050] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0051] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0052] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0053] The principle of SAGD production is to inject high-temperature and high-pressure superheated steam into the oil reservoir, use the latent heat of steam vaporization to heat the oil reservoir, reduce the viscosity of the heavy oil, increase its fluidity, and the heated crude oil flows directly into the production well. Through the action of gravity, horizontal well production is used to obtain a higher oil production rate, so as to achieve the purpose of production and improved recovery. The specific implementation method usually adopts a double horizontal well structure, and two parallel horizontal wells are drilled at the bottom of the oil layer. The upper horizontal well is used as a steam injection well, and the lower horizontal well is used as a production well for oil production. The saturated steam in the injected steam overlaps upward, and the heated crude oil and steam condensate water are discharged to the production well below by gravity and produced together with the saturated water. Under the general trend of low-carbon globalization and the national "dual carbon" goals, solar energy will be used more for steam production in SAGD mining to achieve low-carbon mining of heavy oil, but a large number of ground heat storage systems are still needed to cooperate with the production of superheated steam. However, due to the large scale, high investment and high operation and maintenance costs of the ground heat storage tank system, the cost of heavy oil production and development is increased. There is an urgent need for a superheated steam production system that can fully utilize solar energy, meet the needs of heavy oil development and production, and is low-cost.

[0054] The present application embodiment provides a steam system for use in a heavy oil SAGD production system, such as Figure 1 As shown, the steam system comprises: a first steam generating subsystem 1, a second steam generating subsystem 2, a steam injection subsystem 3 and an operation control subsystem 4;

[0055] The first steam generation subsystem 1 comprises a heat absorber 11, which is used to collect solar radiation energy and heat the first water working medium inside the heat absorber 11 to generate first superheated steam, and input the first superheated steam into the steam injection subsystem 3;

[0056] The second steam generation subsystem 2 comprises a steam injection boiler 21, and the steam injection boiler 21 is used to heat the second water working medium inside the second steam generation subsystem 2 to generate second superheated steam when the second steam generation subsystem 2 is turned on, and input the second superheated steam into the steam injection subsystem 3;

[0057] The steam injection subsystem 3 includes a steam injection well 31 and an underground steam chamber 32. The steam injection well 31 is used to inject the input superheated steam into the underground steam chamber 32. The underground steam chamber 32 is located above the oil reservoir 5 and is used to store the superheated steam and release the superheated steam to the oil reservoir 5, so that the heated heavy oil in the oil reservoir 5 is transported to the production well 6 by steam driving force and gravity driving force. The superheated steam includes the first superheated steam and / or the second superheated steam.

[0058] The operation control subsystem 4 is used to periodically calculate the superheated steam difference based on the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the first superheated steam amount, and send an opening or closing signal to the second steam generating subsystem 2 accordingly according to the calculated superheated steam difference.

[0059] In this embodiment, the absorber 11 of the first steam generating subsystem 1 can adopt the absorber of the existing tower-type concentrating solar collector system, including but not limited to a row tube absorber, a finned tube absorber, a heat pipe absorber, a spiral coil absorber or a cavity absorber. The absorber heats the first water working medium to generate the first superheated steam as the preferred source of superheated steam in the heavy oil SAGD production system.

[0060] In this embodiment, the steam injection boiler 21 of the second steam generating subsystem 2 can generate second superheated steam by burning fossil energy such as coal and natural gas. Compared with the first steam generating subsystem 1, the second steam generating subsystem 2 has a higher carbon emission intensity. When the superheated steam generated by the first steam generating subsystem 1 and the superheated steam storage capacity in the underground steam chamber 32 are insufficient to meet the actual production needs of heavy oil, the second steam generating subsystem 2 serves as an alternative source of superheated steam in the heavy oil SAGD production system.

[0061] In this embodiment, during the heavy oil SAGD production process, the crude oil in the oil reservoir 5 is heated by superheated steam, and the heated crude oil and steam condensate water are discharged to the production well 6 below by gravity and produced together with saturated water. The pore volume of the crude oil production is occupied by steam to form the underground steam chamber 32. The underground steam chamber 32 has good heat storage conditions. When the solar radiation intensity is low, such as on rainy days or at night, although the productivity of the first steam generating subsystem has been greatly reduced, the superheated steam stored in the underground steam chamber 32 can still be used to heat the oil reservoir 5 for a period of time, and the production of the oil field will not stop immediately.

[0062] In this embodiment, when the solar radiation intensity is high and the amount of first superheated steam generated by the first steam generating subsystem 1 is greater than the amount of superheated steam required for crude oil production, the excess superheated steam can be stored in the underground steam chamber 32 .

[0063] In this embodiment, the operation control subsystem 4 periodically calculates the superheated steam difference, and the time setting of the period can refer to the weather conditions and the rising and setting rules of the sun at the location of the production well.

[0064] The steam system of this embodiment does not have a ground heat storage system, and fully utilizes the underground steam chamber formed during the heavy oil SAGD production process to store excess superheated steam and release superheated steam; the solar steam system and the steam injection boiler steam system are coupled and coordinated to fully utilize the solar energy and smooth the fluctuation of the superheated steam amount caused by the instability of solar energy; the superheated steam control method is simple, the calculation amount is small, the dynamic regulation process is fast, the hardware requirements for the operation control subsystem are low, and it is easy to implement, which provides a superheated steam production system with low cost, stable superheated steam output and rapid dynamic response for the clean and efficient production of heavy oil.

[0065] In an exemplary embodiment, the operation control subsystem is used to periodically calculate the superheated steam difference according to the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the amount of the first superheated steam, including:

[0066] The operation control subsystem 4 calculates the required superheated steam amount of the heavy oil SAGD production system according to the preset heavy oil production of the production well;

[0067] The operation control subsystem 4 periodically calculates the existing superheated steam amount, and calculates the superheated steam difference based on the required superheated steam amount; wherein the existing superheated steam amount is the sum of the first superheated steam amount and the superheated steam storage amount of the current cycle, and the superheated steam difference is the difference between the required superheated steam amount and the existing superheated steam amount.

[0068] In this embodiment, the superheated steam storage amount of the current cycle is an accumulated value from the first cycle to the current cycle, and the superheated steam storage amount can be obtained by cumulative calculation by the operation control subsystem 4 .

[0069] In one implementation of this embodiment, the operation control subsystem 4 may provide an input interface for the heavy oil production so that oilfield staff can set the heavy oil production. The operation control subsystem 4 calculates the required superheated steam volume according to the input heavy oil production.

[0070] In another implementation of this embodiment, the operation control subsystem 4 may store the heavy oil production of the production well, and the operation control subsystem 4 reads the heavy oil production and calculates the required superheated steam amount according to the reading result.

[0071] In an exemplary embodiment, sending an opening or closing signal to the second steam generating subsystem 2 according to the calculated superheated steam difference includes:

[0072] The operation control subsystem 4 sends an opening signal to the second steam generating subsystem 2 when the superheated steam difference is greater than zero;

[0073] After the second steam generating subsystem 2 is turned on, the operation control subsystem 4 uses the superheated steam difference as the demand for the second superheated steam, and accordingly sets the power of the steam injection boiler 21 according to the demand for the second superheated steam.

[0074] In an exemplary embodiment, sending an opening or closing signal to the second steam generating subsystem 2 according to the calculated superheated steam difference value also includes:

[0075] The operation control subsystem 4 sends a shutdown signal to the second steam generating subsystem 2 when the superheated steam difference is less than or equal to zero;

[0076] When the superheated steam difference is less than zero, the operation control subsystem 4 uses the absolute value of the superheated steam difference as the excess superheated steam amount, and correspondingly uses the excess superheated steam amount as the superheated steam storage amount for the next cycle.

[0077] In an exemplary embodiment, the steam injection subsystem 3 further includes a first steam pipeline 33, a second steam pipeline 34, a steam injection main pipe 35, a first check valve 36 and a second check valve 37;

[0078] The first steam pipeline 33 is used to connect the absorber 11 and the steam injection main pipe 35. The first one-way valve 36 is arranged on the first steam pipeline 33. When the first one-way valve 36 is opened, the first steam pipeline 33 inputs the first superheated steam generated into the steam injection main pipe 35.

[0079] The second steam pipeline 34 is used to connect the steam injection boiler 21 and the steam injection main pipe 35. The second one-way valve 37 is arranged on the second steam pipeline 34. When the second one-way valve 37 is opened, the second steam pipeline 34 inputs the generated second superheated steam into the steam injection main pipe 35.

[0080] The steam injection main pipe 35 is connected to the steam injection well 31 and is used to inject the first superheated steam and / or the second superheated steam into the steam injection well 31 .

[0081] In this embodiment, the first one-way valve 36 and the second one-way valve 37 can be controlled by the operation control subsystem 4. Only when the first steam generating subsystem 1 is in operation, only the first one-way valve 36 is opened to prevent the first superheated steam from flowing in reverse; only when the second steam generating subsystem 2 is in operation, only the second one-way valve 37 is opened to prevent the second superheated steam from flowing in reverse; when the first steam generating subsystem 1 and the second steam generating subsystem 2 are in operation at the same time, the first one-way valve 36 and the second one-way valve 37 are opened at the same time.

[0082] In an exemplary embodiment, the first steam generation subsystem further includes a heliostat 12, a first water pump 13, a first deaerator 14, a heat absorption tower 15 and a first superheated steam detector 16;

[0083] The heliostat 12 is used to reflect and focus sunlight onto the heat absorber 11;

[0084] The first deaerator 14 is used to access and process the first softened water provided by the softening equipment, and remove the first gas in the first softened water, wherein the first gas includes dissolved oxygen;

[0085] The first water pump 13 is connected to the first deaerator 14 and the heat absorber 11, and is used to inject the first softened water treated by the first deaerator 14 into the heat absorber 11 as the first water working medium;

[0086] The heat absorber 11 is arranged at the top of the heat absorption tower 15;

[0087] The first superheated steam detector 16 is disposed on the first steam pipe 33 and is used to detect the amount of the first superheated steam generated by the heat absorber 11 .

[0088] In this embodiment, the heliostats 12 can form a heliostat field array to reflect solar radiation onto the heat absorber 11 located on the top of the heat absorption tower 15; in terms of mirror material, the heliostats 12 can include but are not limited to tension metal film reflectors or silver-coated glass reflectors.

[0089] In this embodiment, the first gas includes but is not limited to dissolved oxygen, and may also include gases such as carbon dioxide dissolved in the first softened water.

[0090] In this embodiment, the first superheated steam detector can detect the flow rate, temperature and pressure of the first superheated steam, obtain the amount of the first superheated steam through the flow rate of the first superheated steam, and determine whether the first superheated steam reaches the temperature and pressure standards of superheated steam required for heavy oil SAGD production by detecting the temperature and pressure of the first superheated steam.

[0091] In an exemplary embodiment, the second steam generation subsystem further includes a second water pump 22, a second deaerator 23, and a second superheated steam detector 24;

[0092] The second deaerator 23 is used to access and process the second softened water provided by the softening equipment, and remove the second gas in the second softened water, wherein the second gas includes dissolved oxygen;

[0093] The second water pump 22 is connected to the second deaerator 23 and the steam injection boiler 21, and is used to inject the second softened water treated by the second deaerator 23 into the steam injection boiler 21 as the second water working medium;

[0094] The second superheated steam detector 24 is disposed on the second steam pipe 34 and is used to detect the amount of the second superheated steam generated by the steam injection boiler 21 .

[0095] In this embodiment, the second gas includes but is not limited to dissolved oxygen, and may also include gases such as carbon dioxide dissolved in the second softened water.

[0096] In this embodiment, the second superheated steam detector 24 can detect the flow rate, temperature and pressure of the second superheated steam, obtain the amount of the second superheated steam through the flow rate of the second superheated steam, and determine whether the second superheated steam reaches the temperature and pressure standards of superheated steam required for heavy oil SAGD production by detecting the temperature and pressure of the second superheated steam.

[0097] The present application also provides a heavy oil SAGD production system, such as Figure 1 As shown, it includes a production well 6 and a steam system provided in the above embodiment;

[0098] The production well 6 is a horizontal well, whose horizontal section is located in the oil reservoir 5 containing heavy oil and is parallel to the horizontal section of the steam injection well 31 in the steam system. The horizontal section of the production well 6 is located below the horizontal section of the steam injection well 31.

[0099] The steam system in this embodiment includes a first steam generating subsystem 1, a second steam generating subsystem 2, a steam injection subsystem 3 and an operation control subsystem 4. The first steam generating subsystem 1 includes a heat absorber 11, a heliostat 12, a first water pump 13, a first deaerator 14, a heat absorption tower 15 and a first superheated steam detector 16; the second steam generating subsystem 2 includes a steam injection boiler 21, a second water pump 22, a second deaerator 23 and a second superheated steam detector 24; the steam injection subsystem 3 includes a steam injection well 31, an underground steam chamber 32, a first steam pipeline 33, a second steam pipeline 34, a steam injection main pipe 35, a first check valve 36 and a second check valve 37.

[0100] The present application also provides a heavy oil SAGD superheated steam control method, which is applied to the operation control subsystem in the steam system provided in the above embodiment, such as Figure 2 As shown, steps S100-S300 are included:

[0101] S100: periodically obtaining the amount of first superheated steam detected by the first superheated steam detector and the amount of superheated steam stored in the underground steam chamber in the current cycle;

[0102] S200: calculating a superheated steam difference according to a required superheated steam amount, the superheated steam storage amount of the current cycle and the amount of the first superheated steam;

[0103] S300: Sending an opening or closing signal to the second steam generating subsystem according to the superheated steam difference.

[0104] In this embodiment, step S200 includes steps S210-S230:

[0105] S210: Calculating the required amount of superheated steam for the heavy oil SAGD production system according to the preset heavy oil production of the production well;

[0106] S220: Periodically calculating the existing superheated steam amount, where the existing superheated steam amount is the sum of the first superheated steam amount and the superheated steam storage amount of the current cycle;

[0107] S230: Calculate the difference between the required superheated steam amount and the existing superheated steam amount, and use the calculation result as the superheated steam difference.

[0108] In one implementation of this embodiment, the superheated steam difference calculated in S230 is greater than zero, and step S300 executes S311-S312:

[0109] S311: Sending an opening signal to the second steam generating subsystem;

[0110] S312: Using the superheated steam difference as the demand for second superheated steam, and correspondingly setting the power of the steam injection boiler according to the second superheated steam quantity.

[0111] In another implementation manner of this embodiment, if the superheated steam difference calculated by S230 is less than zero, step S300 executes S321-S322; if the superheated steam difference calculated by S230 is equal to zero, step S300 only executes S321;

[0112] S321: Sending a shutdown signal to the second steam generating subsystem;

[0113] S322: taking the absolute value of the superheated steam difference as the excess superheated steam amount, and correspondingly taking the excess superheated steam amount as the superheated steam storage amount for the next cycle.

[0114] The above-mentioned heavy oil SAGD superheated steam control method is specifically described below using an example:

[0115] In the first cycle, the initial value of the superheated steam storage amount is set to 0.

[0116] In the first cycle, the operation control subsystem obtains the first superheated steam volume detected by the first superheated steam detector as V11 = 8000m 3 , the obtained superheated steam storage capacity is V21=0;

[0117] The operation control subsystem calculates the required superheated steam volume of the heavy oil SAGD production system according to the preset heavy oil production volume of the production well, which is V31 = 10000m 3 ;

[0118] The operation control subsystem calculates the existing superheated steam volume V41 = V11 + V21 = 8000m 3 ;

[0119] The operation control subsystem calculates the superheated steam difference V51 = V31-V41 = 2000m 3 ;

[0120] The operation control subsystem determines that V51>0 and sends an opening signal to the second steam generation subsystem;

[0121] Run the control subsystem and set V51 to 2000m 3 As the second superheated steam demand, the corresponding V51 = 2000m 3 Setting the power of the steam injection boiler;

[0122] At the end of the first cycle, the first superheated steam is 8000m 3 The second superheated steam subsystem is based on the second superheated steam demand V51 = 2000m 3 The second superheated steam generated has been used up, and the superheated steam storage capacity at this time is 0, that is, for the second cycle, the superheated steam storage capacity is V22 = 0;

[0123] In the second cycle, the operation control subsystem obtains the first superheated steam volume detected by the first superheated steam detector as V12 = 30000m 3 , the obtained superheated steam storage capacity is V22=0;

[0124] The operation control subsystem calculates the required superheated steam volume of the heavy oil SAGD production system according to the preset heavy oil production volume of the production well, which is V32 = 10000m 3 ;

[0125] The operation control subsystem calculates the existing superheated steam volume V42 = V12 + V22 = 30000m 3 ;

[0126] The operation control subsystem calculates the superheated steam difference V52 = V32-V42 = -20000m 3 ;

[0127] The operation control subsystem determines that V52<0 and sends a shutdown signal to the second steam generation subsystem;

[0128] The operation control subsystem sets the absolute value of V52 |V52| = 20000m3 As the excess superheated steam volume, |V52| is used as the superheated steam storage volume for the third cycle, that is, V23 = 20000m 3 ;

[0129] In the third cycle, the operation control subsystem obtains the first superheated steam volume detected by the first superheated steam detector as V13 = 5000m 3 The obtained superheated steam storage capacity is V23 = 20000m 3 ;

[0130] The operation control subsystem calculates the required superheated steam volume of the heavy oil SAGD production system according to the preset heavy oil production volume of the production well, which is V33 = 10000m 3 ;

[0131] The operation control subsystem calculates the existing superheated steam volume V43 = V13 + V23 = 25000m 3 ;

[0132] The operation control subsystem calculates the superheated steam difference V53 = V33-V43 = -15000m 3 ;

[0133] The operation control subsystem determines that V53<0 and sends a shutdown signal to the second steam generation subsystem;

[0134] The operation control subsystem sets the absolute value of V53 |V53| = 15000m 3 As the excess superheated steam volume, |V53| is used as the superheated steam storage volume for the fourth cycle, that is, V24 = 15000m 3 ;

[0135] In the fourth cycle, due to continuous rainy weather, the operation control subsystem obtains the amount of the first superheated steam detected by the first superheated steam detector as V14 = 0m 3 The obtained superheated steam storage capacity is V24 = 20000m 3 ;

[0136] The operation control subsystem calculates the required superheated steam volume of the heavy oil SAGD production system according to the preset heavy oil production volume of the production well, which is V34 = 10000m 3 ;

[0137] The operation control subsystem calculates the existing superheated steam volume V44 = V14 + V24 = 20000m 3 ;

[0138] The operation control subsystem calculates the superheated steam difference V54 = V34-V44 = -10000m 3 ;

[0139] The operation control subsystem determines that V54<0 and sends a shutdown signal to the second steam generation subsystem;

[0140] The operation control subsystem sets the absolute value of V54 |V54| = 10000m 3 As the excess superheated steam volume, |V54| is used as the superheated steam storage volume for the fifth cycle, that is, V25 = 10000m 3 .

[0141] To facilitate understanding of the meaning of each parameter in the above example, see Table 1 below.

[0142] Table 1 Parameters in the example

[0143] First cycle Second cycle Third cycle Fourth cycle Fifth cycle Amount of first superheated steam V11 V12 V13 V14 Superheated steam storage capacity V21 V22 V23 V24 V25 Required superheated steam V31 V32 V33 V34 Existing superheated steam V41 V42 V43 V44 Superheated steam difference V51 V52 V53 V54

[0144] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A steam system, characterized in that: Applied in a heavy oil SAGD production system, the steam system comprises: a first steam generation subsystem, a second steam generation subsystem, a steam injection subsystem and an operation control subsystem; The first steam generation subsystem includes a heat absorber, which is used to collect solar radiation energy and heat the first water working medium inside the heat absorber to generate first superheated steam, and input it into the steam injection subsystem; The second steam generating subsystem comprises a steam injection boiler, which is used to heat the second water working medium inside the steam generating subsystem to generate second superheated steam when the second steam generating subsystem is turned on, and input the second superheated steam into the steam injection subsystem; The steam injection subsystem comprises a steam injection well and an underground steam chamber, wherein the steam injection well is used to inject the input superheated steam into the underground steam chamber; the underground steam chamber is located above the oil reservoir, and is used to store the superheated steam and release the superheated steam to the oil reservoir, so that the heated heavy oil in the oil reservoir is transported to the production well by steam driving force and gravity driving force; the superheated steam comprises the first superheated steam and / or the second superheated steam; The operation control subsystem is used to periodically calculate the superheated steam difference based on the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the first superheated steam amount, and send an opening or closing signal to the second steam generating subsystem accordingly according to the calculated superheated steam difference.

2. The steam system according to claim 1, characterized in that The operation control subsystem is used to periodically calculate the superheated steam difference according to the required superheated steam amount, the superheated steam storage amount in the underground steam chamber and the amount of the first superheated steam, including: The operation control subsystem calculates the required superheated steam amount of the heavy oil SAGD production system according to the preset heavy oil production amount of the production well; The operation control subsystem periodically calculates the existing superheated steam amount, and calculates the superheated steam difference based on the required superheated steam amount; wherein the existing superheated steam amount is the sum of the first superheated steam amount and the superheated steam storage amount of the current cycle, and the superheated steam difference is the difference between the required superheated steam amount and the existing superheated steam amount.

3. The steam system according to claim 2, characterized in that The sending an opening or closing signal to the second steam generating subsystem according to the calculated superheated steam difference includes: The operation control subsystem sends an opening signal to the second steam generating subsystem when the superheated steam difference is greater than zero; After the second steam generating subsystem is turned on, the operation control subsystem uses the superheated steam difference as the demand for the second superheated steam, and accordingly sets the power of the steam injection boiler according to the demand for the second superheated steam.

4. The steam system according to claim 2, characterized in that: The step of sending an opening or closing signal to the second steam generating subsystem according to the calculated superheated steam difference also includes: The operation control subsystem sends a shutdown signal to the second steam generating subsystem when the superheated steam difference is less than or equal to zero; When the superheated steam difference is less than zero, the operation control subsystem uses the absolute value of the superheated steam difference as the excess superheated steam amount, and correspondingly uses the excess superheated steam amount as the superheated steam storage amount for the next cycle.

5. The steam system according to claim 3, characterized in that: The steam injection subsystem further includes a first steam pipeline, a second steam pipeline, a steam injection main pipe, a first check valve and a second check valve; The first steam pipeline is used to connect the heat absorber and the steam injection main pipe, the first one-way valve is arranged on the first steam pipeline, and the first steam pipeline inputs the first superheated steam generated into the steam injection main pipe when the first one-way valve is opened; The second steam pipeline is used to connect the steam injection boiler and the steam injection main pipe, the second one-way valve is arranged on the second steam pipeline, and the second steam pipeline inputs the second superheated steam generated into the steam injection main pipe when the second one-way valve is opened; The steam injection mother pipe is connected to the steam injection well and is used to inject the first superheated steam and / or the second superheated steam into the steam injection well.

6. The steam system according to claim 5, characterized in that: The first steam generation subsystem further includes a heliostat, a first water pump, a first deaerator, a heat absorption tower and a first superheated steam detector; The heliostat is used to reflect and focus sunlight onto the absorber; The first deaerator is used to access and process the first softened water provided by the softening equipment, and remove the first gas in the first softened water, wherein the first gas includes dissolved oxygen; The first water pump is connected to the first deaerator and the heat absorber, and is used to inject the first softened water treated by the first deaerator into the heat absorber as the first water working medium; The heat absorber is arranged at the top of the heat absorption tower; The first superheated steam detector is disposed on the first steam pipe, and is used to detect the amount of the first superheated steam generated by the heat absorber.

7. The steam system according to claim 5, characterized in that: The second steam generation subsystem further includes a second water pump, a second deaerator, and a second superheated steam detector; The second deaerator is used to access and process the second softened water provided by the softening equipment, and remove the second gas in the second softened water, wherein the second gas includes dissolved oxygen; The second water pump is connected to the second deaerator and the steam injection boiler, and is used to inject the second softened water treated by the second deaerator into the steam injection boiler as the second water working medium; The second superheated steam detector is disposed on the second steam pipe and is used to detect the amount of the second superheated steam generated by the steam injection boiler.

8. A heavy oil SAGD production system, characterized in that: comprising a production well and a steam system as claimed in claims 1-7; The production well is a horizontal well, whose horizontal section is located in the oil reservoir containing heavy oil and is parallel to the horizontal section of the steam injection well in the steam system, and the horizontal section of the production well is located below the horizontal section of the steam injection well.

9. A heavy oil SAGD superheated steam control method, characterized in that: The operation control subsystem used in the steam system according to claims 1 to 7 comprises: periodically acquiring the amount of first superheated steam detected by the first superheated steam detector and the amount of superheated steam stored in the underground steam chamber in the current cycle; calculating a superheated steam difference according to a required superheated steam amount, the superheated steam storage amount of the current cycle, and the amount of the first superheated steam; An opening or closing signal is sent to the second steam generating subsystem according to the superheated steam difference.

10. The heavy oil SAGD superheated steam control method according to claim 9, characterized in that: The generating an opening or closing signal to the second steam generating subsystem according to the superheated steam difference comprises: When the superheated steam difference is greater than zero, sending an opening signal to the second steam generating subsystem; taking the superheated steam difference as the demand for the second superheated steam, and setting the power of the steam injection boiler accordingly according to the demand for the second superheated steam; Alternatively, when the superheated steam difference is less than or equal to zero, sending a shutdown signal to the second steam generating subsystem; When the superheated steam difference is less than zero, the absolute value of the superheated steam difference is used as the excess superheated steam amount, and correspondingly the excess superheated steam amount is used as the superheated steam storage amount for the next cycle.

Images