A high-efficiency utilization system for steam in thermal recovery of thick oil

Abstract

The present application relates to the technical field of oilfield steam injection boiler, and particularly relates to a high-efficiency utilization system for steam in heavy oil thermal recovery. The system comprises: a steam-water separator, an inlet of the steam-water separator is connected with an outlet of the steam injection boiler, a gas outlet of the steam-water separator is connected with a heavy oil well, a liquid outlet of the steam-water separator is connected with an inlet of a flash device, and the steam-water separator is used for separating steam output by the steam injection boiler into steam and liquid; a gas outlet of the flash device is connected with a steam heating scene, a liquid outlet of the flash device is connected with a liquid heat exchange scene; the flash device is used for evaporating salt water output by the steam injection boiler into predetermined temperature flash steam and high-salt water, transmitting the flash steam to the steam heating scene, and / or transmitting the high-salt water to the liquid heat exchange scene. The present application can improve the dryness of saturated steam after steam-water separation to more than 99%, improve the enthalpy value of steam entering the heavy oil well, increase the heavy oil recovery rate, and improve the utilization rate of steam heat at the outlet of the steam injection boiler.

Description

Technical Field

[0001] This invention relates to the field of oilfield steam injection boiler technology, and in particular to a high-efficiency utilization system for heavy oil thermal recovery steam. Background Technology

[0002] Oilfield steam injection boilers are crucial equipment in heavy oil development, used to inject high-temperature steam into underground heavy oil reservoirs to heat the oil, reduce its viscosity, and improve its fluidity. Currently, feedwater for oilfield steam injection boilers is treated using technologies such as ion exchange, reverse osmosis, and ultrafiltration. Among these, ion exchange technology is widely used due to its advantages of simple operation, low treatment cost, and effluent quality meeting the requirements of oilfield steam injection boilers. Ion exchange technology only removes calcium from the boiler feedwater. 2+ Mg 2+ , but Na + Si 2+ Untreated steam can easily precipitate inside the boiler tubes of oilfield steam injection boilers. Oilfield steam injection boilers using ion exchange water treatment technology have outlet steam dryness below 80%, resulting in low boiler outlet steam enthalpy, which limits the improvement of heavy oil recovery. How to increase the steam enthalpy entering the heavy oil thermal recovery wellhead and how to efficiently utilize the hot water after steam separation are urgent problems to be solved in the current heavy oil development process. Summary of the Invention

[0003] This invention proposes a high-efficiency steam utilization system for heavy oil thermal recovery to solve the problems of low steam dryness at the outlet of current steam injection boilers, which affects the recovery rate of heavy oil, and the waste of resources caused by the inefficient utilization of hot water after steam separation.

[0004] According to one aspect of the present invention, a high-efficiency utilization system for heavy oil thermal recovery steam is provided, comprising: a steam-water separator and a flash evaporation device; The inlet of the steam-water separator is connected to the outlet of the steam injection boiler, the gas outlet of the steam-water separator is connected to the heavy oil well, and the liquid outlet of the steam-water separator is connected to the inlet of the flash evaporator. The steam-water separator is used to separate the steam output from the steam injection boiler into steam and liquid. The gas outlet of the flash evaporator is connected to the scene to be heated by steam, and the liquid outlet of the flash evaporator is connected to the scene to be heated by liquid. The flash evaporation device is used to evaporate the brine output from the steam injection boiler into flash steam at a predetermined temperature and high brine, and to transfer the flash steam to a scene to be heated by steam, and / or to transfer the high brine to a scene to be heated by liquid.

[0005] Preferably, the steam-water separator includes: a separation tank, a steam-water mixing chamber, and a turbine separator; The steam-water mixing chamber is provided inside the separation tank. The inlet of the steam-water mixing chamber is connected to the outlet of the steam injection boiler. The steam-water mixing chamber is used to mix the steam and water output from the steam injection boiler. The gas-water mixing chamber is connected to the inlet of the turbine separator, the gas outlet of the turbine separator is connected to the gas phase space inside the separation tank, and the liquid outlet of the turbine separator is connected to the liquid phase space inside the separation tank. A gas outlet is provided at the top of the gas phase space inside the separation tank, and the gas outlet is connected to the heavy oil well. A liquid outlet is provided at the bottom of the liquid phase space inside the separation tank, and the liquid outlet is connected to the flash evaporation device.

[0006] Preferably, the top of the water-gas mixing chamber is flat, and the turbine separator is disposed on the top of the water-gas mixing chamber; The bottom surface of the soda-water mixing chamber is an inclined surface, or the bottom of the soda-water mixing chamber is funnel-shaped; The bottom of the gas-water mixing chamber is provided with a drain hole, which is connected to the liquid phase space inside the separation tank.

[0007] Preferably, the steam-water separator further includes: a separation element; The separation element is located at the top of the separation tank, below the gas outlet, and is used to separate moisture from the steam output by the turbine separator.

[0008] Preferably, the separating element is: a corrugated plate separator, a steam distribution plate, a louver, or a wire mesh.

[0009] Preferably, the flash evaporation device includes: a flash evaporation tank and a pressure regulating mechanism; The inlet of the flash tank is connected to the liquid outlet of the steam-water separator, the steam outlet of the flash tank is connected to the scene to be heated by steam, and the liquid outlet of the flash tank is connected to the scene to be heated by liquid. The pressure regulating mechanism is connected to the inlet and outlet of the flash tank. The pressure regulating mechanism is used to adjust the flash pressure in the flash tank to a corresponding predetermined pressure according to the predetermined boiling point when heating the brine in the flash tank.

[0010] Preferably, the pressure regulating mechanism includes: an inlet pressure regulating valve, a gas outlet pressure regulating valve, and a liquid outlet pressure regulating valve; The inlet pressure regulating valve is installed at the inlet of the flash tank, and the inlet pressure regulating valve is also used to regulate the flow rate of the brine entering the flash tank; The gas outlet pressure regulating valve is installed at the steam outlet of the flash tank; The liquid outlet pressure regulating valve is installed at the liquid outlet of the flash tank. The outlet pressure regulating valve is also used to regulate the steam pressure output by the flash tank.

[0011] Preferably, the scenario to be heated by steam includes: a heat tracing system, a fuel atomization system, and / or a fuel heating system within the station.

[0012] Preferably, the liquid heat exchange scenario includes: boiler feedwater preheater heat exchange.

[0013] Preferably, a pressure-reducing device is installed at the inlet of the flash evaporator; The pressure-reducing device includes: a throttling orifice plate or a pressure-reducing valve.

[0014] The present invention has at least the following beneficial effects: This invention proposes a high-efficiency steam utilization system for heavy oil thermal recovery. By incorporating a steam-water separator, the steam stiffness is improved, and by adding a flash evaporation process, the utilization rate of steam and its separated hot water is increased. This invention can achieve a saturated steam dryness of over 99% after steam-water separation, thereby increasing the steam enthalpy entering the heavy oil well, increasing the heavy oil recovery rate, and improving the utilization rate of steam heat at the injection boiler outlet. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the specification, serve to explain the technical solutions of the present invention.

[0016] Figure 1 This diagram illustrates the structure of a high-efficiency steam utilization system for heavy oil thermal recovery according to an embodiment of the present invention. Figure 2 A schematic diagram of a steam-water separator according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of the structure of a flash evaporation apparatus according to an embodiment of the present invention is shown.

[0017] In the diagram, 1-separation tank, 2-steam-water mixing chamber, 3-turbine separator, 4-steam inlet, 5-drain hole, 6-drain outlet, 7-gas collection port, 8-corrugated plate separator, 9-flash tank, 10-inlet pressure regulating valve, 11-gas outlet pressure regulating valve, 12-liquid outlet pressure regulating valve, 13-80% dryness steam, 14-salt water, 15-high saline water, 16-flash steam, 17-softened water, 18-saturated steam. Detailed Implementation

[0018] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0019] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0020] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0021] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art will understand that the present invention can be practiced without certain specific details. In some instances, methods, means, elements, and circuits well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention.

[0022] Figure 1 This diagram illustrates the structure of a high-efficiency steam utilization system for heavy oil thermal recovery according to an embodiment of the present invention. Figure 2 A schematic diagram of a steam-water separator according to an embodiment of the present invention is shown; Figure 3 A schematic diagram of a flash evaporation apparatus according to an embodiment of the present invention is shown. Figure 1-3 As shown, a high-efficiency steam utilization system for heavy oil thermal recovery includes: a steam-water separator and a flash evaporator; the inlet of the steam-water separator is connected to the outlet of a steam injection boiler, the gas outlet of the steam-water separator is connected to a heavy oil well, and the liquid outlet of the steam-water separator is connected to the inlet of the flash evaporator; the steam-water separator is used to separate the steam output from the steam injection boiler into steam and liquid; the gas outlet of the flash evaporator is connected to the scene to be heated by steam, and the liquid outlet of the flash evaporator is connected to the scene to be heated by liquid; the flash evaporator is used to evaporate the brine output from the steam injection boiler into flash steam at a predetermined temperature and high brine, and to transfer the flash steam to the scene to be heated by steam, and / or, to transfer the high brine to the scene to be heated by liquid.

[0023] In embodiments of the present invention, such as Figure 1As shown, the system operation process is as follows: 80% dryness steam 13 from the steam injection boiler outlet enters the steam-water separator through the inlet, where it is separated into saturated steam 18 with a dryness greater than 99% and brine 14. The saturated steam 18 is transported to the heavy oil well through the gas outlet of the steam-water separator for reservoir development; the brine 14 enters the flash evaporator through the liquid outlet of the steam-water separator and the inlet of the flash evaporator.

[0024] In the flash evaporator, some of the water in the brine 14 evaporates into flash steam 16, which is then transferred to the scene to be heated by steam through the gas outlet of the flash evaporator. The high brine 15 after flash evaporation in the flash evaporator is transferred to the scene to be heated by liquid through the liquid outlet of the flash evaporator.

[0025] In this invention, the steam-water separator includes: a separation tank 1, a steam-water mixing chamber 2, and a turbine separator 3; the steam-water mixing chamber 2 is disposed inside the separation tank 1, and the inlet of the steam-water mixing chamber 2 is connected to the outlet of the steam injection boiler, the steam-water mixing chamber 2 being used to mix the steam and water output from the steam injection boiler; the steam-water mixing chamber 2 is connected to the inlet of the turbine separator 3, the gas outlet of the turbine separator 3 is connected to the gas phase space inside the separation tank 1, and the liquid outlet of the turbine separator 3 is connected to the liquid phase space inside the separation tank 1; a gas outlet is disposed at the top of the gas phase space inside the separation tank 1, the gas outlet being connected to the heavy oil well, and a liquid outlet is disposed at the bottom of the liquid phase space inside the separation tank 1, the liquid outlet being connected to the flash evaporation device.

[0026] In embodiments of the present invention, such as Figure 2 As shown, the separation tank 1 of the steam-water separator is equipped with components such as a steam-water mixing chamber 2 and a turbine separator 3, which can separate the wet steam output from the steam injection boiler into saturated steam with a steam dryness greater than 99%.

[0027] Because the steam output from the steam injection boiler still contains a lot of moisture, and the output of the steam injection boiler is not stable enough, there are intermittent and segmented gas or liquid outputs in the pipeline, which will cause frequent changes in the amount of steam and water entering the steam-water separator, affecting the separation effect and liquid level balance of the turbine separator 3.

[0028] By setting up the steam-water mixing chamber 2, the incoming steam and water can be fully mixed. That is, after the wet steam output from the steam injection boiler enters the steam-water separator separation tank 1, it first enters the steam-water mixing chamber 2 for full mixing, and then enters the turbine separator 3 for steam-water separation.

[0029] The saturated steam separated by the turbine separator 3 enters the gas phase space of the steam-water separator from the top cap (gas outlet) of the turbine separator 3, which is the upper half of the space inside the separation tank 1; the brine separated by the turbine separator 3 enters the liquid phase space of the steam-water separator from the gap between the inner and outer cylinders of the turbine separator 3, which is the liquid outlet of the turbine separator 3, which is the lower half of the space inside the separation tank 1.

[0030] The saturated steam separated by the turbine separator 3 enters the heavy oil well through the steam injection pipeline via the gas collection port 7 (gas outlet) at the top of the separator tank 1; the brine enters the flash evaporator through the drain port 6 (liquid outlet) at the bottom of the separator tank 1.

[0031] In this invention, the top of the steam-water mixing chamber 2 is a flat surface, and the turbine separator 3 is disposed on the top of the steam-water mixing chamber 2; the bottom surface of the steam-water mixing chamber 2 is an inclined surface, or the bottom of the steam-water mixing chamber 2 is funnel-shaped; a drain hole 5 is provided at the bottom of the steam-water mixing chamber 2, and the drain hole 5 is connected to the liquid phase space inside the separation tank 1.

[0032] In this embodiment of the invention, the steam-water mixing chamber 2 is located inside the separation tank 1, and a steam inlet 4 is provided on the side wall of the separation tank 1. The steam inlet 4 is connected to the steam-water mixing chamber 2, that is, the steam inlet 4 is the inlet of the steam-water mixing chamber 2.

[0033] The top surface of the water-gas mixing chamber 2 is flat and is used to house the turbine separator 3. The inlet of the turbine separator 3 is connected to the upper outlet of the water-gas mixing chamber 2.

[0034] The bottom surface of the steam-water mixing chamber 2 is inclined, and a drain hole 5 is provided at the lowest point of the inclined surface. The drain hole 5 is connected to the liquid phase space inside the separation tank 1. The drain hole 5 and the inclined bottom surface of the steam-water mixing chamber 2 are used to allow excess liquid (water) in the steam-water mixing chamber 2 to enter the liquid phase space of the separation tank 1 through the drain hole 5 when the system stops running or when the dryness of the inlet steam is low, and finally enter the flash evaporator.

[0035] In this invention, the steam-water separator further includes a separation element; the separation element is disposed at the top of the separation tank 1, located below the gas outlet, and is used to separate moisture from the steam output by the turbine separator 3.

[0036] In this invention, the separating element is: a corrugated plate separator (8) or a steam distribution plate or a louver or a wire mesh.

[0037] In this embodiment of the invention, the corrugated plate separator 8 is located at the top of the separation tank 1 of the steam-water separator. After being separated by the turbine separator 3, the steam enters the gas phase space inside the separation tank 1, passes through the corrugated plate separator 8, undergoes further water separation by the corrugated plate separator 8, and then enters the heavy oil well through the gas collecting port 7 at the top of the separation tank 1 and the steam injection pipeline.

[0038] The water separated by the corrugated plate separator 8 flows downward into the liquid phase space inside the separation tank 1.

[0039] The corrugated plate separator 8 inside the separator tank 1 can use secondary separation elements such as steam distribution plates, louvers, and wire mesh.

[0040] In this invention, the flash evaporation device includes: a flash evaporation tank 9 and a pressure regulating mechanism; the inlet of the flash evaporation tank 9 is connected to the liquid outlet of the steam-water separator, the steam outlet of the flash evaporation tank 9 is connected to the scene to be heated by steam, and the liquid outlet of the flash evaporation tank 9 is connected to the scene to be heated by liquid; the pressure regulating mechanism is connected to the inlet and outlet of the flash evaporation tank 9, and the pressure regulating mechanism is used to adjust the flash evaporation pressure in the flash evaporation tank 9 to a corresponding predetermined pressure according to a predetermined boiling point when heating the brine contained in the flash evaporation tank 9.

[0041] In embodiments of the present invention, such as Figure 3 As shown, the flash evaporation device consists of a pressure regulating mechanism and a flash tank 9. By controlling the pressure regulating mechanism, the pressure inside the flash tank 9 can be adjusted, thereby regulating the flash evaporation temperature. At the same time, the pressure regulating mechanism can also control parameters such as the flash steam quantity and flash pressure, so as to achieve controllable flash evaporation.

[0042] The drain outlet 6 at the bottom of the separation tank 1 of the steam-water separator is connected to the flash tank 9. The brine output from the steam-water separator enters the flash tank 9 through the inlet. The real-time pressure inside the flash tank 9 is adjusted to a predetermined pressure by a pressure regulating mechanism. The brine inside the flash tank 9 is heated. When the boiling point of the brine under the predetermined pressure is reached, the brine evaporates rapidly to form flash steam. The flash steam is delivered to the scene to be heated by steam through the steam outlet of the flash tank 9. The high brine content generated after flashing is delivered to the scene to be heated by liquid through the liquid outlet of the flash tank 9.

[0043] In this invention, the pressure regulating mechanism includes: an inlet pressure regulating valve 10, a gas outlet pressure regulating valve 11, and a liquid outlet pressure regulating valve 12; the inlet pressure regulating valve 10 is installed at the inlet of the flash tank 9, and the inlet pressure regulating valve 10 is also used to regulate the flow rate of brine entering the flash tank 9; the gas outlet pressure regulating valve 11 is installed at the steam outlet of the flash tank 9; the liquid outlet pressure regulating valve 12 is installed at the liquid outlet of the flash tank 9; the outlet pressure regulating valve is also used to regulate the steam pressure output by the flash tank 9.

[0044] In this embodiment of the invention, when the inlet pressure regulating valve 10 is opened, the brine output from the steam-water separator enters the flash tank 9; by adjusting the opening of the inlet pressure regulating valve 10, the flow rate of the brine entering the flash tank 9 can be adjusted.

[0045] As brine is injected, the pressure inside the flash tank 9 gradually increases. When the real-time pressure reaches the predetermined pressure, the inlet pressure regulating valve 10 is closed. If the real-time pressure inside the flash tank 9 is too high, the gas outlet pressure regulating valve 11 and / or the liquid outlet pressure regulating valve 12 are opened to release pressure inside the flash tank 9 until the real-time pressure inside the flash tank 9 equals the predetermined pressure, at which point the gas outlet pressure regulating valve 11 and / or the liquid outlet pressure regulating valve 12 are closed.

[0046] The brine in the flash tank 9 is heated until it reaches the boiling point of the brine at a predetermined pressure, at which point the brine rapidly evaporates to form flash steam. The gas outlet pressure regulating valve 11 and / or the liquid outlet pressure regulating valve 12 are opened, and the flash steam in the flash tank 9 is transported to the scene to be heated by steam through the steam outlet; the high-salt content brine generated after flashing is transported to the scene to be heated by liquid through the liquid outlet of the flash tank 9.

[0047] The inlet pressure regulating valve 10 and the outlet pressure regulating valve of the flash evaporator are electric valves or pneumatic valves, which can be automatically controlled by connecting to the controller to realize the controllable flash evaporation process.

[0048] In this invention, the scenario to be steam heated includes: heat tracing, fuel atomization and / or fuel heating systems within the station.

[0049] In this invention, the liquid heat exchange scenario includes: boiler feedwater preheater heat exchange.

[0050] In this embodiment of the invention, the flash steam output by the flash evaporator can be used for pipeline heating, fuel atomization, fuel heating, and other station processes within the plant. The high-salinity brine, after evaporating some of the water, is transported to the boiler feedwater preheater for heat exchange. The high-salinity brine exchanges heat with the boiler feedwater (softened water 17) within the boiler feedwater preheater. The high-salinity brine transfers heat to the boiler feedwater, which is then used for processes such as well washing (well washing reuse).

[0051] Among them, the water preheater can be in the form of a shell-and-tube heat exchanger, a tube-and-shell heat exchanger, or a U-tube heat exchanger.

[0052] In this invention, a pressure-reducing device is installed at the inlet of the flash evaporation device; wherein the pressure-reducing device includes: a throttling orifice plate or a pressure-reducing valve.

[0053] In this embodiment of the invention, a pressure reducing device such as a throttling orifice plate and a pressure reducing valve can be installed before the inlet pressure regulating valve 10 of the flash evaporator to reduce the pressure level of the pressure regulating valve and save costs.

[0054] In this embodiment of the invention, taking a heavy oil thermal recovery steam injection well site in an oilfield as an example, the steam injection boiler has an evaporation capacity of 19.5 t / h, an outlet steam pressure of 17.2 MPa, a steam temperature of 353°C, and a steam dryness of 80%. After being connected to the steam-water separator of the heavy oil thermal recovery steam high-efficiency utilization system of the present invention, the steam dryness of the injected heavy oil well is increased to 99.8%, and the steam enthalpy value is increased from 2494.87 kJ / kg to 2534.91 kJ / kg, an increase of 1.6%; the flash steam output from the flash evaporator for use in the station's heat tracing system is 2.1 t / h (saturated steam with a gauge pressure of 0.1 MPa); the high-salinity water output from the flash evaporator for feedwater preheating is 1.77 t / h, which can heat the 19.5 t / h boiler feedwater from 20°C to 28°C.

[0055] The total steam utilization rate of the heavy oil thermal recovery steam high-efficiency utilization system provided by this invention is increased from 16.42 t / h to 17.73 t / h, and the boiler outlet steam quality utilization rate is increased from 84.2% to 90.9%, an improvement of 6.7%.

[0056] The total heat utilization of steam in the heavy oil thermal recovery steam high-efficiency utilization system provided by the present invention increases the total heat utilization of steam from 11668.3kW to 12769.7kW, and the boiler outlet steam heat utilization rate increases from 90.9% to 99.5%, an improvement of 8.6%.

[0057] It is understood that the various embodiments mentioned above in this invention can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this invention will not elaborate further.

[0058] This invention achieves a steam dryness of over 99% by incorporating components such as a steam-water mixing chamber 2, a turbine separator 3, a corrugated plate separator 8, and a gas collecting pipe inside the steam-water separator. A drain hole 5 at the bottom of the steam-water mixing chamber 2 removes excess brine when the device stops operating or when the inlet steam dryness is low. A flash evaporation device is used to flash-evaporate the brine after steam-water separation. The flash-evaporated steam is used for station heating, fuel atomization, and fuel heating. The high-salt-content brine after flash evaporation is used for well washing and reuse after heat exchange with boiler feedwater. The flash evaporation device can control parameters such as the flash steam quantity and pressure by adjusting the pressure of the pressure regulating valve, achieving controllable flash evaporation. A throttling orifice plate and a pressure reducing valve can be installed before the inlet pressure regulating valve 10 to reduce the pressure rating of the pressure regulating valve.

[0059] This invention utilizes a steam-water separator to increase the enthalpy of steam entering the heavy oil wellhead, thereby improving the heavy oil recovery rate. It also utilizes a flash evaporation device and a boiler feedwater waste heat device to improve the utilization rate of steam outlet from the oilfield steam injection boiler. This invention has at least the following advantages: 1. It increases the enthalpy of steam entering the heavy oil wellhead through a steam-water separator and a flash evaporation device, thus improving the heavy oil recovery rate. 2. It treats the brine after steam-water separation using a flash evaporation process, and the flash steam is used for boiler fuel oil heating, combustion atomization, and heat tracing at the steam injection station, improving the utilization rate of steam outlet from the oilfield steam injection boiler and reducing the operating costs of the heavy oil thermal recovery station. 3. It uses the high brine content after flash evaporation to heat the boiler feedwater, improving the utilization rate of heat from the steam outlet from the steam injection boiler. 4. The steam-water separator uses components such as a turbine separator 3 and a corrugated plate separator 8 to enhance the separation effect. The dryness of the steam injected into the heavy oil well after separation can reach over 99%, improving the wet steam separation efficiency. 5. A drain hole 5 is provided at the bottom of the steam-water mixing chamber 2 of the steam-water separator to remove excess brine and improve the service life of the steam-water separator. 6. The flash evaporator consists of an inlet pressure regulating valve 10, a tank, and an outlet pressure regulating valve, etc., which can adjust parameters such as flash steam quantity and pressure, improving the utilization range of flash steam. 7. A throttling orifice plate, pressure reducing valve, or other pressure-reducing equipment can be installed before the inlet pressure regulating valve 10 of the flash evaporator to lower the pressure rating of the regulating valve and reduce equipment investment.

[0060] This invention utilizes a steam-water separator and a flash evaporation device to process steam with 80% dryness. The saturated steam separated by the steam-water separator enters the steam injection network, while the separated brine enters the flash evaporation device. The flash-evaporated steam is used in the steam injection station process. The high-salt water after flash evaporation exchanges heat with boiler feedwater and is then reused in the heavy oil well washing process. Compared with existing oilfield steam injection boiler steam dryness enhancement devices, this invention improves steam utilization by adding a flash evaporation process; it improves steam heat utilization by using the heat from the high-salt water to heat the boiler feedwater; and by optimizing the steam-water separator structure, the dryness of the saturated steam after steam-water separation is increased to over 99%, increasing the steam enthalpy value entering heavy oil wells and increasing heavy oil recovery.

[0061] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A high-efficiency steam utilization system for heavy oil thermal recovery, characterized in that, include: Steam-water separator and flash evaporator; The inlet of the steam-water separator is connected to the outlet of the steam injection boiler, the gas outlet of the steam-water separator is connected to the heavy oil well, and the liquid outlet of the steam-water separator is connected to the inlet of the flash evaporator. The steam-water separator is used to separate the steam output from the steam injection boiler into steam and liquid. The gas outlet of the flash evaporator is connected to the scene to be heated by steam, and the liquid outlet of the flash evaporator is connected to the scene to be heated by liquid. The flash evaporation device is used to evaporate the brine output from the steam injection boiler into flash steam at a predetermined temperature and high brine, and to transfer the flash steam to a scene to be heated by steam, and / or to transfer the high brine to a scene to be heated by liquid.

2. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 1, characterized in that, The steam-water separator includes: a separation tank (1), a steam-water mixing chamber (2), and a turbine separator (3); The steam-water mixing chamber (2) is provided inside the separation tank (1). The inlet of the steam-water mixing chamber (2) is connected to the outlet of the steam injection boiler. The steam-water mixing chamber (2) is used to mix the steam and water output by the steam injection boiler. The gas-water mixing chamber (2) is connected to the inlet of the turbine separator (3), the gas outlet of the turbine separator (3) is connected to the gas phase space inside the separation tank (1), and the liquid outlet of the turbine separator (3) is connected to the liquid phase space inside the separation tank (1). The gas outlet is provided at the top of the gas phase space inside the separation tank (1) and is connected to the heavy oil well. The liquid outlet is provided at the bottom of the liquid phase space inside the separation tank (1) and is connected to the flash evaporation device.

3. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 2, characterized in that: The top of the steam-water mixing chamber (2) is flat, and the turbine separator (3) is located on the top of the steam-water mixing chamber (2); The bottom surface of the soda-water mixing chamber (2) is an inclined surface, or the bottom of the soda-water mixing chamber (2) is funnel-shaped; The bottom of the gas-water mixing chamber (2) is provided with a drain hole (5), which is connected to the liquid phase space inside the separation tank (1).

4. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 2, characterized in that, The steam-water separator further includes: a separation element; The separation element is located at the top of the separation tank (1) and below the gas outlet. The separation element is used to separate the moisture in the steam output by the turbine separator (3).

5. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 4, characterized in that: The separating element is: a corrugated plate separator (8) or a steam distribution plate or a louver or a wire mesh.

6. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 1, characterized in that, The flash evaporation device includes: a flash evaporation tank (9) and a pressure regulating mechanism; The inlet of the flash tank (9) is connected to the liquid outlet of the steam-water separator, the steam outlet of the flash tank (9) is connected to the scene to be heated by steam, and the liquid outlet of the flash tank (9) is connected to the scene to be heated by liquid. The pressure regulating mechanism is connected to the inlet and outlet of the flash tank (9). The pressure regulating mechanism is used to adjust the flash pressure in the flash tank (9) to the corresponding predetermined pressure according to the predetermined boiling point when heating the brine in the flash tank (9).

7. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 6, characterized in that, The pressure regulating mechanism includes: an inlet pressure regulating valve (10), a gas outlet pressure regulating valve (11), and a liquid outlet pressure regulating valve (12). The inlet pressure regulating valve (10) is installed at the inlet of the flash tank (9), and the inlet pressure regulating valve (10) is also used to regulate the flow rate of the brine entering the flash tank (9); The gas outlet pressure regulating valve (11) is installed at the steam outlet of the flash tank (9); The liquid outlet pressure regulating valve (12) is installed at the liquid outlet of the flash tank (9); The outlet pressure regulating valve is also used to regulate the steam pressure output by the flash tank (9).

8. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 1, characterized in that: The scenarios requiring steam heating include: heat tracing, fuel atomization, and / or fuel heating systems within the station.

9. The heavy oil thermal recovery steam high-efficiency utilization system according to claim 1, characterized in that, The scenarios for liquid heat exchange include: boiler feedwater preheater heat exchange.

10. The heavy oil thermal recovery steam high-efficiency utilization system according to any one of claims 1-9, characterized in that: A pressure-reducing device is installed at the inlet of the flash evaporator; The pressure-reducing device includes: a throttling orifice plate or a pressure-reducing valve.

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