A water-vapor heat exchange system, its movable steam injection boiler and steam injection method

Abstract

The present invention provides a water-vapor heat exchange system, a movable steam injection boiler and a steam injection method thereof, which include a water heat exchanger located between a water pump and the convection section of the boiler, a flue gas heat exchanger located in the convection section of the boiler, and a radiation section heat exchanger located in the radiation section of the boiler. The water heat exchanger includes an inner heat exchanger tube and an outer heat exchanger tube that exchange heat with each other and are respectively used for the circulation of water medium. The inner heat exchanger tube, the flue gas heat exchanger, the outer heat exchanger tube and the radiation section heat exchanger are sequentially connected along the direction of water medium circulation. After the water medium absorbs heat in the convection section, it enters the water heat exchanger as a heat source to heat the water medium that has not entered the convection section, so that its temperature rises and exceeds the dew point temperature, so as to avoid the low-temperature corrosion of the finned tube by the flue gas. A superheat section is connected at the flue gas outlet of the radiation section, and a superheat section heat exchanger for further heating and evaporating the water medium is arranged in the superheat section. The wet saturated steam coming out of the radiation section is continuously heated and evaporated through the superheat section heat exchanger, ensuring the steam injection effect on the oil well.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction, and particularly to a water-vapor heat exchange system, a movable steam injection boiler and a steam injection method thereof. Background Art

[0002] The oil extraction industry is an important foundation for promoting stable economic development and national defense security. Heavy oil is an important raw material for the lubricating oil industry and the aerospace industry. The development of heavy oil is of great significance to the energy industry. At present, the main problem in heavy oil extraction is the high cost. The steam injection process is often used in heavy oil extraction. By injecting high-temperature steam into the oil layer, the viscosity of heavy oil is reduced, making it easier to extract crude oil. It is urgent to solve the problem of reducing steam injection costs. The current technical situation of oil fields is as follows: In the steam injection link, the steam equipment is mainly 70-ton fluidized beds and 23-ton coal-fired and gas-fired boilers. Each fixed boiler has fixed pipelines radially connected to the surrounding oil production wells.

[0003] However, the current fixed boiler steam injection process has the following problems: First, affected by the steam injection radius, the effective operation rate of boilers in Xinjiang Oilfield is only about 40%. More than half of the more than 400 boilers cannot operate effectively; the equipment occupancy and depreciation costs are high; Second, the supporting steam injection pipeline network is long and has a large diameter, and the pipeline construction investment is large; Third, in the steam injection pipeline, the single-well steam injection radius is long, and the heat loss is serious; Fourth, the distances of single wells from the boiler are different, and it is impossible to finely manage and compare the oil-gas ratios of single wells.

[0004] Patent document CN202012901U discloses a movable steam injection boiler. A cooling chamber is arranged between the radiant section and the convection section of the steam injection boiler. The burner is arranged on the radiant section. The burner and the blower are connected through an air duct. The convection section is arranged above the cooling chamber, and the chimney is at the outlet end of the convection section. The main pipeline of the steam injection boiler is water that has been filtered and dehardened by a water treatment device, enters a plunger pump, and enters the tube bundle in the cooling chamber from the plunger pump. The water temperature entering the convection section is increased by absorbing the heat of the flue gas. After the water flows out of the convection section, it directly enters the radiant section, overcoming the deficiencies of the existing steam injection boilers, such as too high flue gas temperature during operation and acid corrosion of the tube bundle in the convection section. However, the flue gas outlet at the radiant section is the position with the highest temperature. Using the cooling section to heat the water inevitably causes waste of the heat of the flue gas boiler. Summary of the Invention

[0005] The purpose of the present invention is to provide a water-vapor heat exchange system, a movable steam injection boiler and a steam injection method thereof to solve the above-mentioned technical problems. The initial water medium is preheated by the water medium that has absorbed heat in the convection section to avoid low-temperature corrosion of the finned tubes by the flue gas, and the heat of the boiler can be fully utilized, and the operation rate of the steam injection boiler can be increased, and the equipment depreciation cost can be reduced.

[0006] To achieve the above object, the present invention provides the following solutions: a water-vapor heat exchange system for a steam injection boiler, comprising a water heat exchanger located between a water pump and the convection section of the boiler, a flue gas heat exchanger located in the convection section of the boiler, and a radiant section heat exchanger located in the radiant section of the boiler. The water heat exchanger includes an inner heat exchanger tube and an outer heat exchanger tube that exchange heat with each other and are respectively used for the circulation of water medium. The inner heat exchanger tube, the flue gas heat exchanger, the outer heat exchanger tube, and the radiant section heat exchanger are sequentially connected along the direction of water medium circulation.

[0007] Preferably, a superheat section is connected to the flue gas outlet of the radiant section. A superheat section heat exchanger for further heating and evaporating the water medium is provided in the superheat section, and the superheat section heat exchanger is connected to the radiant section heat exchanger.

[0008] A mobile steam injection boiler is also provided, comprising a mobile trailer and a steam injection boiler body provided on the mobile trailer. The steam injection boiler body includes a radiant section, a superheat section, a convection section, and a water heat exchanger. The radiant section is horizontally arranged on the mobile trailer, and a flue gas outlet is opened at the top of its end. The superheat section and the convection section are sequentially connected to the flue gas outlet and are stacked and placed above the flue gas outlet. The water heat exchanger is fixed on the top of the radiant section and is located on one side of the flue gas outlet.

[0009] Preferably, a steam-water separator for drying the steam flowing out of the superheat section is provided on the mobile trailer.

[0010] Preferably, a pipeline compensator is connected to the outlet of the steam-water separator. The pipeline compensator is in a corrugated structure capable of telescopic deformation.

[0011] Preferably, the pipeline compensator includes a plurality of parallel branch pipes. A rotating connection pipe is provided between two adjacent branch pipes. The rotating connection pipe includes two branch connection pipes rotatably connected coaxially. Two adjacent branch pipes are respectively perpendicular to and rotatably connected to each branch connection pipe.

[0012] Preferably, a metering pipe or a quick-connect pipe for replacing the metering pipe is detachably connected between the pipeline compensator and the oil well injection port.

[0013] Preferably, a high-pressure pump for pumping softened water into the steam injection boiler body is provided on the mobile trailer. The high-pressure pump is electrically connected to the metering pipe, and the high-pressure pump controls the amount of softened water pumped in according to the steam amount measured by the metering pipe.

[0014] Preferably, a combustion system is provided on the radiant section. The combustion system includes a burner, a blower, and a gas pipeline supporting the burner. The burner and the blower are adaptively fixed on the side wall of the radiant section.

[0015] There is also provided a steam injection method for a movable steam injection boiler, including the following steps:

[0016] S1. Block layout before steam injection: Form a block with each steam injection production wellhead, and set up an oil and gas metering room near the block. The oil and gas metering room and each steam injection production wellhead are connected through an oil pipeline, forming a radial pipe network centered on the oil and gas metering room;

[0017] S2. Pipeline layout before steam injection: Connect each oil and gas metering room through a steam injection pipeline, and steam injection stations are provided on both the steam injection pipeline and the oil pipeline located between adjacent oil and gas metering rooms;

[0018] S3. Boiler movement before steam injection: Drain the water in the steam injection boiler, move the movable trailer to the steam injection station corresponding to the oil well where steam injection is required, and connect the pipeline compensator to the steam injection manifold of the steam injection station;

[0019] S4. Prepare steam: Start the combustion system. After the radiation section reaches the corresponding temperature, start the high-pressure pump and pump in softened water. The softened water sequentially enters the heat exchange inner pipe of the water-type heat exchanger and the flue gas heat exchanger, forms a steam-water mixture and then returns to the heat exchange outer pipe of the water-type heat exchanger, and exchanges heat with the softened water in the heat exchange inner pipe. After the steam-water mixture flows out of the heat exchange outer pipe, it sequentially enters the radiation section heat exchanger and the superheat section heat exchanger to form high-temperature and high-pressure saturated steam;

[0020] S4. Steam injection: Inject the high-temperature and high-pressure saturated steam into the pipe network through the metering pipe. After obtaining the corresponding steam volume through the metering pipe, turn off the high-pressure pump.

[0021] The present invention has achieved the following technical effects compared with the prior art:

[0022] First, the water-type heat exchanger includes a heat exchange inner pipe and a heat exchange outer pipe that exchange heat with each other and are respectively used for the circulation of the water medium. The heat exchange inner pipe, the flue gas heat exchanger, the heat exchange outer pipe, and the radiation section heat exchanger are sequentially connected along the direction of the water medium circulation. After the water medium absorbs heat in the convection section, it enters the water-type heat exchanger as a heat source to heat the water medium that has not entered the convection section, so that its temperature rises and exceeds the dew point temperature, to avoid the low-temperature corrosion of the finned tube by the flue gas.

[0023] Second, a superheat section is connected and provided at the flue gas outlet of the radiation section. A superheat section heat exchanger for further heating and evaporating the water medium is provided in the superheat section. The superheat section heat exchanger is connected to the radiation section heat exchanger. The wet saturated steam coming out of the radiation section is continuously heated and evaporated through the superheat section heat exchanger to further increase its dryness, ensuring the steam injection effect on the oil well.

[0024] Third, the radiation section is horizontally placed on a movable trailer. A flue gas outlet is provided at the top of its end. The superheat section and the convection section are successively connected to the flue gas outlet and are stacked and placed above the flue gas outlet. The water-type heat exchanger is fixed on the top of the radiation section and is located on one side of the flue gas outlet. That is to say, the original boiler and chimney assembly with large volume and dispersed structure are arranged into a highly integrated structure. Then, the whole can be fixed by a wheeled movable vehicle frame and towed by a power head to achieve movement. Furthermore, the operation time rate of the steam injection boiler can be improved, and the equipment depreciation cost can be reduced. Moreover, after the boiler is made mobile, the total length of the steam injection pipeline network can be shortened, and then the diameter requirement of the steam injection pipeline network can be reduced, significantly reducing the pipeline network investment and the later maintenance loss.

[0025] Fourth, a steam-water separator is provided on the movable trailer, which is used to further dry the water steam flowing out of the superheat section, so as to ensure the steam injection effect on the oil well.

[0026] Fifth, the pipeline compensator includes multiple parallel branches. A rotating connecting pipe is provided between two adjacent branches. The rotating connecting pipe includes two branch connecting pipes that are coaxially and rotatably connected. Two adjacent branches are respectively perpendicular and rotatably connected to each branch connecting pipe, so as to ensure the flexible installation between the output end of the steam injection boiler and the oil well, avoid excessive movement of the whole boiler caused by using fixed pipe fittings, and improve the overall working efficiency.

[0027] Sixth, a metering pipe or a quick-installation pipe for replacing the metering pipe is detachably connected between the pipeline compensator and the oil well injection port. When single-well metering is required according to different steam injection positions, the metering pipe is connected to the single-well steam injection pipeline, so that the metering is accurate. When metering is not required, the metering pipe is replaced with a quick-installation pipe to resume production, so that the operation time rate of the metering pipe is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is the front view of the boiler system structure of the present invention;

[0030] Figure 2 It is the top view of the boiler system structure of the present invention;

[0031] Figure 3 It is the front view of the water pump system structure of the present invention;

[0032] Figure 4 It is the top view of the water pump system structure of the present invention;

[0033] Figure 5 Front view of the structural diagram of the steam-water separator system of the present invention;

[0034] Figure 6 Top view of the structural diagram of the steam-water separator system of the present invention;

[0035] Figure 7 Front view of the overall structure of the present invention;

[0036] Figure 8 Side view of the overall structure of the present invention;

[0037] Wherein, 1 - chimney, 2 - superheat section, 3 - convection section, 4 - radiation section, 5 - burner, 6 - movable trailer, 7 - combustion control system, 8 - water pipeline, 9 - water inlet pipeline, 10 - gas pipeline, 11 - water heat exchanger, 12 - blower, 13 - plunger pump, 14 - mounting bracket, 15 - steam-water separator, 16 - steam-water separation tank, 17 - check valve. Specific embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] The purpose of the present invention is to provide a water-vapor heat exchange system, its movable steam injection boiler and steam injection method to solve the above-mentioned existing technical problems, preheat the initial water medium with the water medium after absorbing heat in the convection section to avoid low-temperature corrosion of the finned tubes by flue gas, and can make full use of the heat of the boiler, and can improve the operation rate of the steam injection boiler and reduce the equipment depreciation cost.

[0040] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] Please refer to Figure 1-8As shown in the figure, in this embodiment, a water-vapor heat exchange system for a steam injection boiler is provided, which includes a water heat exchanger 11 located between a water pump and the convection section 3 of the boiler, a flue gas heat exchanger located in the convection section 3 of the boiler, and a radiation section 4 heat exchanger located in the radiation section 4 of the boiler. Preferably, each heat exchanger is composed of single finned tubes horizontally reciprocating around to improve the utilization efficiency of the heat of the boiler and the flue gas. Moreover, the inner surface of the radiation section 4 of the boiler is coated with HTEE-E refractory far-infrared radiation coating, and the thickness requirement is more than 2 mm to ensure the fire resistance of the radiation section 4 of the boiler. The water heat exchanger 11 includes an inner tube and an outer tube of the heat exchanger that exchange heat with each other and are respectively used for the circulation of the water medium. The inner tube of the heat exchanger, the flue gas heat exchanger, the outer tube of the heat exchanger, and the radiation section 4 heat exchanger are sequentially connected along the direction of the water medium circulation. It is known that the presence of sulfuric acid vapor significantly increases the dew point of the flue gas. If the temperature of the finned tube is relatively low and the wall temperature is lower than the dew point of the flue gas, then the sulfuric acid vapor will condense on the finned tube, causing sulfuric acid corrosion. Then the water medium enters the convection section 3 through the water heat exchanger 11, and after absorbing heat in the convection section 3, it enters the water heat exchanger 11 as a heat source to heat the water medium that has not entered the convection section 3, so that its temperature rises and exceeds the dew point temperature, usually required to be about 110 - 120 °C, to avoid the low-temperature corrosion of the flue gas on the finned tube. Moreover, the main function of the water heat exchanger 11 is to heat the initial water medium, but it is necessary to improve the energy efficiency of the boiler as much as possible. The best way is to make the most of the energy of the gas, avoid adding other heating methods, introducing other energies, reducing the utilization rate of the gas energy, and adding other heating structures will inevitably cause the heaviness of the entire device and affect the subsequent integration of the entire device on the vehicle.

[0042] Among them, the flue gas heat exchanger is composed of single finned tubes horizontally reciprocating to form a trapezoidal structure and is located in the low-temperature area of the flue gas. Its function is to further reduce the temperature of the flue gas and improve the utilization efficiency of the heat of the boiler. Moreover, the water medium is pressurized by a plunger pump 13 and enters each link of the boiler. The specific pressure is generally greater than 0.4 MPa, and the boiling point of water reaches 140 degrees Celsius, and it does not turn into steam until the radiation section 4, so as to further reduce the steam corrosion of the flue gas heat exchanger.

[0043] At the flue gas outlet of the radiation section 4, a superheat section 2 is connected. Since the temperature at the flue gas outlet of the radiation section 4 is the highest position of the boiler body temperature, a superheat section 2 heat exchanger for further heating and evaporating the water medium is provided in the superheat section 2. The superheat section 2 heat exchanger is connected to the radiation section 4 heat exchanger to ensure the maximum heating of the water medium. Among them, after the water medium flows out of the water heat exchanger 11, it enters the radiation section 4 to continue heating and evaporating, and is transformed into a high-temperature and high-pressure wet saturated steam with a dryness of 75% ± 5%. The wet saturated steam coming out of the radiation section 4 is continuously heated and evaporated through the superheat section 2 heat exchanger, and is transformed into a high-temperature and high-pressure wet saturated steam with a dryness of 85%, and then is injected into the oil well through the steam injection pipeline network.

[0044] Further, a movable steam injection boiler is provided, which includes a movable trailer 6 and a steam injection boiler body arranged on the movable trailer 6. The steam injection boiler body includes a radiation section 4, a superheat section 2, a convection section 3, and a water heat exchanger 11. The radiation section 4 is horizontally arranged on the movable trailer 6, and a flue gas outlet is opened at the top of its end. The superheat section 2 and the convection section 3 are successively connected to the flue gas outlet and are stacked and placed above the flue gas outlet. The convection section 3 is connected to a boiler chimney 1. The water heat exchanger 11 is fixed on the top of the radiation section 4 and is located on one side of the flue gas outlet. Preferably, to ensure the stable installation of the water heat exchanger 11, a mounting bracket 14 is fixed on the top of the radiation section 4, arranging the original large-sized and structurally dispersed boiler and chimney 1 assembly into a highly integrated structure. Then, the whole can be fixed by a wheeled movable vehicle frame. During steam injection, it is towed by a power head to achieve movement, and the steam injection boiler is hauled to each steam injection site where steam injection is required, and is connected to the steam injection manifold through a movable pipeline, thereby being able to improve the operation time rate of the steam injection boiler and reduce the equipment depreciation cost. Moreover, after the boiler is made mobile, the total length of the steam injection pipeline network can be shortened, thereby reducing the diameter requirement of the steam injection pipeline network, significantly reducing the pipeline network investment and the later maintenance loss. And with mobile and precise steam injection, the distance difference between single wells is shortened, fine management can be realized, the oil-gas ratio data of single wells can be effectively collected and compared, high-yield wells and low-efficiency wells can be identified, and precise control of single wells can be achieved. Preferably, the flue gas outlet of the steam injection boiler is in a notch-shaped structure, that is, the height of the steam injection boiler where the flue gas outlet is provided is relatively lower than the height where the radiation section 4 is provided, so that the overall center of gravity of the convection section 3 and the boiler chimney 1 is reduced, ensuring the stability during the movement process.

[0045] A steam-water separator 15 for drying the steam flowing out of the superheat section 2 is arranged on the movable trailer 6 to ensure the steam injection effect on the oil well. The steam-water separator 15 includes a steam-water separation tank 16 and corresponding connecting pipelines. When recovering heavy oil by steam injection, it mainly relies on the heat energy of the steam to heat the crude oil. The water in the steam is not very helpful for heavy oil production. Instead, it will increase the occupied formation pore volume, increase the water cut of the produced fluid, and reduce the crude oil production. In order to greatly improve, the higher the dryness of the injected steam, the higher the recovery rate of heavy oil. Therefore, the steam-water separator 15 is set to further ensure the dryness of the steam. Preferably, a steam-water separation device is also arranged between the radiation section 4 and the superheat section 2 to separate the saturated steam from the steam-water mixture through the steam-water separation device and then send it into the superheater for heating, so that the steam temperature is increased and converted into superheated steam. After the temperature of the superheated steam reaches about 470 °C, it can be injected into a spray desuperheater and remixed with the saturated water separated by the steam-water separation device. The mixed temperature drops to about 370 - 390 °C, and finally the superheated steam is injected into the well.

[0046] The outlet of the steam separator 15 is connected with a pipeline compensator. The pipeline compensator is in a corrugated structure capable of telescopic deformation, so as to adapt to the position of the oil well injection port. According to different working conditions, the bending or extension degree of the corrugated structure is changed, ensuring the stability and flexibility of the connection between the steam injection boiler and the oil well injection port. As a preferred embodiment of the present invention, the pipeline compensator includes multiple parallel branches. A rotating connection pipe is provided between two adjacent branches. The rotating connection pipe includes two branch connection pipes rotatably connected coaxially. Two adjacent branches are respectively perpendicular to and rotatably connected to each branch connection pipe, further ensuring the flexible installation between the output end of the steam injection boiler and the oil well, avoiding excessive movement of the whole boiler caused by using fixed pipe fittings, and improving the overall working efficiency.

[0047] A metering pipe or a quick-install pipe for replacing the metering pipe is detachably connected between the pipeline compensator and the oil well injection port. In the connection mode of the metering device in the prior art, the welding connection mode is adopted, and the replacement is very inconvenient. Therefore, most of them are connected to the main pipeline, so that the single well cannot be metered. In the present invention, a detachable connection mode of the pipeline is adopted between the pipeline compensator and the single oil well injection port, such as the quick-install clamp head connection mode. When single well metering is required, the metering pipe is connected to the single well steam injection pipeline. In this way, the metering is accurate. When metering is not required, the metering pipe is replaced with a quick-install pipe to resume production. In this way, the operation rate of the metering pipe, that is, the equipment utilization rate, is significantly improved. Preferably, a one-way valve 17 and a stop valve are further provided between the pipeline compensator and the oil well injection port. The steam generated by the steam injection boiler passes through the one-way valve 17 and the stop valve and is injected into the oil well through the steam injection pipeline network.

[0048] A high-pressure pump for pumping softened water into the steam injection boiler body is provided on the movable trailer 6. Preferably, it is a plunger pump 13. The high-pressure pump is connected to the water heat exchanger 11 through a water delivery pipeline 8, and is connected to the water supply system through a water inlet pipeline 9. The high-pressure pump is electrically connected to the metering pipe. The high-pressure pump controls the amount of softened water pumped in according to the steam volume measured by the metering pipe. Moreover, the water medium is pressurized by the plunger pump 13 and enters each link of the boiler. The specific pressure is generally greater than 0.4 MPa, and the boiling point of water reaches 140 degrees Celsius, and it does not turn into steam until the radiation section 4, so as to further reduce the steam corrosion of the flue gas heat exchanger.

[0049] The radiation section 4 is equipped with a combustion system, which includes a burner 5, a blower 12, and a gas pipeline 10 supporting the burner 5. The burner 5 and the blower 12 are adaptively fixed on the side wall of the radiation section 4. The burner 5 is connected to the gas supply system through the gas pipeline 10. Among them, the original burner 5 main unit, the blower 12, and the supporting pipelines are relatively large in volume and cannot meet the installation requirements of the mobile boiler. It is necessary to comprehensively upgrade and transform the original burner 5. After the transformation, the power of the burner 5 is not less than 15 MW. Replace the blower and air duct with high efficiency, and reduce the air duct size to meet the requirements of the on-vehicle space and air volume. And the combustion system includes a gas control system adapted to the transformed combustion system. The gas control system includes a burner 5 control and compound regulation system installed in the control cabinet, and has the following functions: an electronic compound regulator for driving the gas and the air damper; it can clearly display the operating status and initial fault values of the burner 5 and perform real-time conversion with the PLC; a burner 5 program control system; the alarm information of the burner 5 is displayed in Chinese on the touch screen; the temperature of the burner 5 throat thermal resistor is displayed on the touch screen; when the burner 5 switches from low fire to high fire, it can be manually adjusted. And the combustion control system 7 includes an automatic ignition, an automatic operation control, and an automatic boiler shutdown control system. Preferably, other structures of the steam injection boiler are replaced from the original parts with large volume and low efficiency to a highly efficient integrated structure.

[0050] The overall steam injection oil production pipe network system includes: each steam injection oil production wellhead, which is distributed in each area of the oilfield and is connected to the underground oil layer through the Christmas tree and the downhole tubing. The metering station is composed of each steam injection oil production wellhead into a block, and a metering station is set near the block to perform metering work on the surrounding blocks. The main pipeline connects the metering station and the surrounding wellheads through the main pipeline, forming a radial pipe network centered on the metering station. The steam injection boiler, when injecting steam, the steam injection boiler is transported to the steam injection site and connected to the steam injection manifold through the movable pipeline. The water, electricity, and gas station is arranged in a point-like layout. Water, electricity, and gas are all required by the boiler during steam injection. The water station provides the heating medium for the boiler, the power station provides electrical energy for the electrical equipment of the boiler, and the gas station provides the combustion energy for the boiler. Among them, the interfaces of water, electricity, and gas have fixed positions. If the mobile boiler is to be pulled away, only the boiler is pulled away, and the site remains, so the utilization rate of the boiler is higher.

[0051] Furthermore, a steam injection method for a movable steam injection boiler is provided, including the following steps:

[0052] S1. Block layout before steam injection: Each steam injection oil production wellhead is formed into a block, and an oil and gas metering station is set near the block. The oil and gas metering station and each steam injection oil production wellhead are connected through an oil pipeline, forming a radial pipe network centered on the oil and gas metering station;

[0053] S2. Pipeline layout before steam injection: Each oil and gas metering station is connected through a steam injection pipeline, and steam injection sites are provided on both the steam injection pipeline and the oil pipeline located between adjacent oil and gas metering stations;

[0054] S3. Boiler movement before steam injection: Drain the water in the steam injection boiler, move the movable trailer 6 to the steam injection station corresponding to the oil well where steam injection is required, and connect the pipeline compensator to the steam injection manifold of the steam injection station.

[0055] S4. Steam preparation: Start the combustion system. After the radiation section 4 reaches the corresponding temperature, start the high-pressure pump and pump in softened water. The softened water sequentially enters the heat exchange inner tube of the water heat exchanger 11 and the flue gas heat exchanger, forms a steam-water mixture and then returns to the heat exchange outer tube of the water heat exchanger 11, and exchanges heat with the softened water in the heat exchange inner tube. After the steam-water mixture flows out of the heat exchange outer tube, it sequentially enters the heat exchanger of the radiation section 4 and the heat exchanger of the superheat section 2 to form high-temperature and high-pressure saturated steam.

[0056] S4. Steam injection: Inject the high-temperature and high-pressure saturated steam into the pipe network through the metering pipe. After obtaining the corresponding steam volume through the metering pipe, turn off the high-pressure pump.

[0057] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0058] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A steam injection method for a movable steam injection boiler, characterized in that, A movable steam injection boiler for the water-vapor heat exchange system of a steam injection boiler The movable steam injection boiler includes the water-vapor heat exchange system of the steam injection boiler. The water-vapor heat exchange system of the steam injection boiler includes a water heat exchanger located between a water pump and the convection section of the boiler, a flue gas heat exchanger located in the convection section of the boiler, and a radiation section heat exchanger located in the radiation section of the boiler. Both the flue gas heat exchanger and the radiation section heat exchanger are composed of single finned tubes horizontally reciprocating and surrounding. The water heat exchanger includes an inner heat exchanger tube and an outer heat exchanger tube that exchange heat with each other and are respectively used for the circulation of water medium. The inner heat exchanger tube, the flue gas heat exchanger, the outer heat exchanger tube, and the radiation section heat exchanger are sequentially connected along the direction of water medium circulation. The movable steam injection boiler further includes a movable trailer and a steam injection boiler body arranged on the movable trailer. The steam injection boiler body includes a radiation section, a superheat section, a convection section, and a water heat exchanger. The radiation section is horizontally arranged on the movable trailer, and a flue gas outlet is opened at the top of its end. The superheat section and the convection section are sequentially connected to the flue gas outlet and are stacked and placed above the flue gas outlet. The water heat exchanger is fixed on the top of the radiation section and is located on one side of the flue gas outlet. A superheat section is connected to the flue gas outlet of the radiation section. A superheat section heat exchanger for further heating and evaporating the water medium is arranged in the superheat section. The superheat section heat exchanger is connected to the radiation section heat exchanger. The steam injection method of the movable steam injection boiler includes the following steps: S1. Block layout before steam injection: Form a block with each steam injection oil production wellhead. An oil and gas metering room is set near the block. The oil and gas metering room and each steam injection oil production wellhead are connected through an oil pipeline to form a radial pipe network centered on the oil and gas metering room. S2. Pipeline layout before steam injection: Connect each oil and gas metering room through a steam injection pipeline. Steam injection stations are arranged on both the steam injection pipeline and the oil pipeline located between adjacent oil and gas metering rooms. S3. Boiler movement before steam injection: Drain the water in the steam injection boiler, move the movable trailer to the steam injection station corresponding to the oil well where steam injection is required, and connect the pipeline compensator to the steam injection manifold of the steam injection station. S4. Steam preparation: Start the combustion system. After the radiation section reaches the corresponding temperature, start the high-pressure pump and pump in softened water. The softened water sequentially enters the inner heat exchange tube of the water heat exchanger and the flue gas heat exchanger, forms a steam-water mixture and then returns to the outer heat exchange tube of the water heat exchanger, and exchanges heat with the softened water in the inner heat exchange tube. After the steam-water mixture flows out of the outer heat exchange tube, it sequentially enters the radiation section heat exchanger and the superheat section heat exchanger to form high-temperature and high-pressure saturated steam. S5. Steam injection: Inject the high-temperature and high-pressure saturated steam into the pipe network through a metering pipe. After obtaining the corresponding steam volume through the metering pipe, turn off the high-pressure pump.

2. The steam injection method of the movable steam injection boiler according to claim 1, characterized in that, A steam-water separator for drying the water steam flowing out of the superheat section is arranged on the movable trailer.

3. The steam injection method of the movable steam injection boiler according to claim 2, characterized in that The outlet of the steam-water separator is connected with a pipeline compensator. The pipeline compensator is in a corrugated structure that can expand and contract and deform.

4. The steam injection method of the movable steam injection boiler according to claim 3, characterized in that, The pipeline compensating pipe includes multiple sections of branch pipes arranged in parallel. A rotating connecting pipe is provided between two adjacent branch pipes. The rotating connecting pipe includes two branch connecting pipes rotatably connected coaxially. Two adjacent branch pipes are respectively perpendicular to and rotatably connected to each branch connecting pipe.

5. The steam injection method of the movable steam injection boiler according to claim 3 or 4, characterized in that A metering pipe or a quick-loading pipe for replacing the metering pipe is detachably connected between the pipeline compensating pipe and the oil well injection port.

6. The steam injection method of the movable steam injection boiler according to claim 5, characterized in that, A high-pressure pump for pumping softened water into the steam injection boiler body is provided on the movable trailer. The high-pressure pump is electrically connected to the metering pipe, and the high-pressure pump controls the amount of softened water pumped in according to the steam amount measured by the metering pipe.

7. The steam injection method of the movable steam injection boiler according to claim 1, characterized in that, A combustion system is provided on the radiant section. The combustion system includes a burner, a blower, and a gas pipeline supporting the burner. The burner and the blower are fixedly fitted on the side wall of the radiant section.

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