A carbon dioxide purification delivery injection system for EOR flooding

Abstract

The utility model discloses a kind of carbon dioxide purification delivery injection systems for EOR flooding, containing purification module and delivery module, purification module contains air inlet, heat exchanger and gas-liquid separator are equipped in the downstream of air inlet, the downstream of the gas phase export of gas-liquid separator is equipped with dehydration tower, first branch pipeline and second branch pipeline are equipped at the gas phase export of dehydration tower, the downstream of first branch pipeline is equipped with dehydration condenser, the downstream of second branch pipeline is equipped with carbon dioxide condenser, the downstream of carbon dioxide condenser is equipped with purification tower, the downstream of purification tower is equipped with finished product intermediate tank, the downstream of finished product intermediate tank is equipped with industrial carbon dioxide storage tank. The utility model is by with carbon dioxide pressurization to dense phase state, avoid the gas-liquid two-phase flow in carbon dioxide delivery process, eliminate the risk of slug flow, pipeline front end and end are respectively equipped with serve as a ball and receive ball barrel, can be realized pig sending under not stop delivery state, can realize oil reservoir low-cost efficient carbon dioxide flooding.

Description

Technical Field

[0001] This utility model relates to a carbon dioxide flooding system, and more specifically, a carbon dioxide purification, delivery and injection system for EOR flooding. Background Technology

[0002] Currently, domestic oilfield EOR (Exhaust Orifice Recovery) mainly utilizes industrial waste gas to capture carbon dioxide, which is then transported to the oilfield injection point by truck or ship. This process has two main drawbacks: firstly, the carbon capture cost is relatively high; secondly, the carbon dioxide pressure needs to be controlled at 2 MPa and the temperature at around -25°C during transportation. Due to the limitations of temperature and pressure conditions, the size and volume of carbon dioxide storage tanks must be strictly controlled. When the oilfield injection volume is large and the carbon dioxide source and injection site are far apart, the transportation volume is small and the transportation cost is high. Utility Model Content

[0003] Therefore, it is necessary to provide a carbon dioxide purification, delivery, and injection system for EOR oil displacement to address the aforementioned technical problems.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A carbon dioxide purification, delivery, and injection system for EOR (Excess Oil Reduction) oil displacement is characterized in that the system comprises a purification module and a delivery module, wherein the delivery module is located downstream of the purification module.

[0006] In a preferred embodiment of this utility model, the purification module includes an air inlet, a heat exchanger and a gas-liquid separator are provided downstream of the air inlet, a dehydration tower is provided downstream of the gas phase outlet of the gas-liquid separator, a first branch pipe and a second branch pipe are provided at the gas phase outlet of the dehydration tower, a dehydration condenser is provided downstream of the first branch pipe, a carbon dioxide condenser is provided downstream of the second branch pipe, a purification tower is provided downstream of the carbon dioxide condenser, a finished product intermediate tank is provided downstream of the purification tower, and an industrial carbon dioxide storage tank is provided downstream of the finished product intermediate tank.

[0007] In a preferred embodiment of this utility model, the conveying module includes a first mass flow meter, a pair of parallel high-pressure reciprocating pumps are provided downstream of the first mass flow meter, a ball launching tube and an emergency shut-off valve are provided downstream of the high-pressure reciprocating pumps, a friction booster pump is provided downstream of the emergency shut-off valve, a first booster pipe and a second booster pipe are provided at the outlet of the friction booster pump, a filter, a second mass flow meter and a dense phase injection pump are provided downstream of the first booster pipe, and a ball receiving tube is provided downstream of the second booster pipe.

[0008] In a preferred embodiment of this utility model, the temperature of the liquid carbon dioxide in the intermediate tank is 5 degrees Celsius and the pressure is 4 MPa, while the temperature of the liquid carbon dioxide in the industrial carbon dioxide storage tank is -20 degrees Celsius and the pressure is 2 MPa.

[0009] In a preferred embodiment of the present invention, the conveying module further includes an venting riser.

[0010] In a preferred embodiment of this utility model, the preset pressure of the booster pump is 8.1 MPa.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] This invention provides a carbon dioxide purification, delivery, and injection system for EOR (Exhaust Orifice Recovery) oil recovery. This system purifies high-concentration carbon dioxide from the gas field using a dehydration tower and purification tower. After being metered by a mass flow meter, the purified carbon dioxide is pumped into a high-pressure reciprocating pump, increasing the pressure to over 7.38 MPa before being piped to the oilfield terminal. A dense-phase injection pump then further increases the pressure to over 20 MPa and injects it into the formation. This invention avoids two-phase flow during carbon dioxide transportation by pressurizing the carbon dioxide to a dense phase, eliminating the risk of clogging. The pipeline is equipped with a launching tube and a receiving tube at the front and rear ends, respectively, allowing for pig deployment without interrupting operations. It offers advantages such as good operational stability, large transport capacity, and high economic efficiency, enabling low-cost and high-efficiency carbon dioxide oil recovery in oil reservoirs. Attached Figure Description

[0013] To more clearly illustrate the solutions in this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the connection structure of the carbon dioxide purification, delivery and injection system for EOR oil displacement according to this utility model.

[0015] The markings in the diagram are explained as follows: 1. Air inlet; 10. Industrial carbon dioxide storage tank; 11. First mass flow meter; 12. High-pressure reciprocating pump; 13. Launching tube; 14. Emergency shut-off valve; 15. Vent riser; 16. Friction booster pump; 161. First booster pipeline; 162. Second booster pipeline; 17. Filter; 18. Second mass flow meter; 19. Dense phase injection pump; 2. Heat exchanger; 20. Receiving tube; 3. Gas-liquid separator; 4. Dehydration tower; 41. First branch pipeline; 42. Second branch pipeline; 5. Dehydration condenser; 7. Carbon dioxide condenser; 8. Purification tower; 9. Finished product intermediate tank; S1. Purification module; S2. Conveying module. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, the carbon dioxide purification delivery and injection system for EOR oil displacement includes a purification module S1 and a delivery module S2, with the delivery module S2 located downstream of the purification module S1.

[0018] The purification module S1 includes an air inlet 1. Downstream of the air inlet 1 are a heat exchanger 2 and a gas-liquid separator 3. Downstream of the gas phase outlet of the gas-liquid separator 3 is a dehydration tower 4. At the gas phase outlet of the dehydration tower 4 are a first branch pipe 41 and a second branch pipe 42. Downstream of the first branch pipe 41 is a dehydration condenser 5. Downstream of the second branch pipe 42 is a carbon dioxide condenser 7. Downstream of the carbon dioxide condenser 7 is a purification tower 8. Downstream of the purification tower 8 is a finished product intermediate tank 9. Downstream of the finished product intermediate tank 9 is an industrial carbon dioxide storage tank 10.

[0019] The conveying module S2 includes a first mass flow meter 11. Downstream of the first mass flow meter 11, there is a pair of parallel high-pressure reciprocating pumps 12. Downstream of the high-pressure reciprocating pumps 12, there is a launching tube 13 and an emergency shut-off valve 14. Downstream of the emergency shut-off valve 14, there is a friction booster pump 16. At the outlet of the friction booster pump 16, there is a first booster pipe 161 and a second booster pipe 162. Downstream of the first booster pipe 161, there is a filter 17, a second mass flow meter 18 and a dense phase injection pump 19. Downstream of the second booster pipe 162, there is a receiving tube 20.

[0020] In addition, the conveying module S2 also includes an venting riser 15.

[0021] The following describes the operation of the carbon dioxide purification, delivery, and injection system used for EOR oil displacement.

[0022] First, the carbon dioxide feed gas (20℃, 7.2MPa) from the gas well is throttled (8.9℃, 4.4MPa) and enters the inlet 1 and heat exchanger 2, where it exchanges heat with the gaseous Freon (19.4℃, 4.4MPa). Then it enters the gas-liquid separator 3, and the separated gas phase enters the dehydration tower 4 to contact the condensed liquid carbon dioxide, removing water and oil from the feed gas.

[0023] Next, the dehydrated gas (9℃, 4.35MPa) from the top of the dehydration tower is split into two streams: the first branch pipe 41 and the second branch pipe 42. One stream passes through the first branch pipe 41, is condensed (1℃, 4.3MPa) by the top condenser 5, and then enters the reflux tank 6 to return to the dehydration tower 4. The other stream passes through the second branch pipe 42, where the carbon dioxide gas is condensed (2℃, 4.15MPa) by the carbon dioxide condenser 7 and then enters the purification tower 8. At the bottom of the purification tower, the product is partially vaporized by the reboiler and undergoes mass transfer with the liquid carbon dioxide at the top, achieving carbon dioxide purification. The bottom product carbon dioxide is then sent to the industrial carbon dioxide storage tank 10 (1.8MPa, -21.5℃, liquid) via the finished product intermediate tank 9 (4MPa, 5℃).

[0024] Next, the liquid (4MPa, 5℃, liquid) from the intermediate carbon dioxide product tank 9 is metered by the first mass flow meter 11 and then enters the high-pressure reciprocating pump 12, increasing the pressure from 4MPa to 9.3MPa. At this point, the carbon dioxide changes from a liquid state to a dense phase (pressure > 7.38MPa, -56℃ < temperature < 31.4℃). Simultaneously, when the carbon dioxide purification unit shuts down, the liquid CO2 (2MPa, -20℃) in the carbon dioxide storage tank 10 can also serve as an emergency backup gas source to ensure system operation.

[0025] Next, two high-pressure reciprocating pumps (12) are installed, one for operation and one for standby. Pressure monitoring instruments are installed upstream and downstream of the pumps. The liquid phase pump uses pressure to regulate the pump speed. Before starting the main pump, the vent valve of the main transfer pump should be manually opened to release the carbon dioxide. After confirming that the main pump is full of liquid carbon dioxide, the vent valve should be closed. The outlet electric ball valve should be slightly opened to start the main transfer pump. After the pump runs for 10 seconds, the outlet electric ball valve should be fully opened, and the main transfer pump start-up is complete. During station operation, the standby pump is in a cold standby state.

[0026] Next, when the pressure along the pipeline is below 8.1 MPa, a booster pump 16 needs to be installed at an appropriate location along the pipeline. When the pressure along the pipeline is not lower than 8.1 MPa, no booster pump is needed. During the transportation process, once the pipeline temperature rises to ambient temperature, it can be ensured that the carbon dioxide remains within the dense phase range and will not undergo phase change. This avoids the problem of carbon dioxide vaporization during general liquid transportation, which makes it unsuitable for dense phase injection pumps to draw in the same phase.

[0027] Finally, the pressurized dense phase carbon dioxide is piped to the downstream injection point, filtered by filter 17, metered by the second mass flow meter 18, and then injected into the formation by dense phase injection pump 19 to achieve EOR oil displacement.

[0028] It should be noted that this system is equipped with both safety valve venting and manual venting. Safety valve venting directly releases air to the atmosphere, while manual venting is connected to the vent manifold 15. Safety valve venting uses a "ball valve + safety valve" configuration, with both upstream and downstream ball valves open and locked to prevent accidental operation. Manual venting uses a "ball valve + vent valve" configuration, with both ball valve and vent valve closed.

[0029] This carbon dioxide purification and injection system for EOR (Enhanced Oil Recovery) utilizes high-concentration carbon dioxide from carbon dioxide gas fields. After distillation, dehydration, and liquefaction purification, the carbon dioxide is pressurized from a general liquid state to a dense-phase liquid state (above the critical pressure of 7.38 MPa and below the critical temperature of 31.4℃) and transported to the oilfield injection point via pipeline. This ensures that the carbon dioxide remains in a dense-phase state during pipeline transportation without phase change or slug flow. Then, a dedicated high-pressure carbon dioxide injection pump injects it into the deep formation of the oilfield, realizing carbon dioxide flooding from the carbon dioxide gas well to the oilfield injection well. The entire process is characterized by low cost, long transportation distance, large transportation volume, and good economic efficiency, effectively improving the oilfield's EOR and promoting the effective operation of the CCUS (Enhanced Coal-Gas-Induced Gas) project.

[0030] This carbon dioxide purification and injection system for EOR (Enhanced Oil Recovery) uses a dehydration tower and purification tower within the system to purify high-concentration carbon dioxide from the gas field. After being metered by a mass flow meter, it enters a high-pressure reciprocating pump, which increases the pressure of the liquid carbon dioxide to over 7.38 MPa before pipeline transportation to the oilfield terminal. A dense-phase injection pump then increases the pressure to over 20 MPa and injects it into the formation. This invention avoids two-phase flow during carbon dioxide transportation by pressurizing the carbon dioxide to a dense phase, eliminating the risk of clogging. The pipeline is equipped with a pig launcher and a pig receiver at the front and rear ends, respectively, allowing for pig deployment without interrupting production. It boasts advantages such as good operational stability, large transport capacity, and high economic efficiency, enabling low-cost and high-efficiency carbon dioxide flooding of oil reservoirs.

[0031] Obviously, the embodiments described above are only some embodiments of this application, and not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application.

Claims

1. A carbon dioxide purification, delivery, and injection system for EOR (Exhaust Oil Reduction) oil displacement, characterized in that, The carbon dioxide purification and delivery injection system for EOR oil displacement includes a purification module (S1) and a delivery module (S2), wherein the delivery module (S2) is located downstream of the purification module (S1).

2. The carbon dioxide purification, delivery, and injection system for EOR oil displacement according to claim 1, characterized in that, The purification module (S1) includes an air inlet (1), a heat exchanger (2) and a gas-liquid separator (3) are provided downstream of the air inlet (1), a dehydration tower (4) is provided downstream of the gas phase outlet of the gas-liquid separator (3), a first branch pipe (41) and a second branch pipe (42) are provided at the gas phase outlet of the dehydration tower (4), a dehydration condenser (5) is provided downstream of the first branch pipe (41), a carbon dioxide condenser (7) is provided downstream of the second branch pipe (42), a purification tower (8) is provided downstream of the carbon dioxide condenser (7), a finished product intermediate tank (9) is provided downstream of the purification tower (8), and an industrial carbon dioxide storage tank (10) is provided downstream of the finished product intermediate tank (9).

3. The carbon dioxide purification, delivery, and injection system for EOR oil displacement according to claim 1, characterized in that, The conveying module (S2) includes a first mass flow meter (11), and a pair of parallel high-pressure reciprocating pumps (12) are provided downstream of the first mass flow meter (11). A ball launching tube (13) and an emergency shut-off valve (14) are provided downstream of the high-pressure reciprocating pumps (12). A friction booster pump (16) is provided downstream of the emergency shut-off valve (14). A first booster pipe (161) and a second booster pipe (162) are provided at the outlet of the friction booster pump (16). A filter (17), a second mass flow meter (18) and a dense phase injection pump (19) are provided downstream of the first booster pipe (161). A ball receiving tube (20) is provided downstream of the second booster pipe (162).

4. The carbon dioxide purification, delivery, and injection system for EOR oil displacement according to claim 2, characterized in that, The temperature of the liquid carbon dioxide in the intermediate tank (9) is 5 degrees Celsius and the pressure is 4 MPa. The temperature of the liquid carbon dioxide in the industrial carbon dioxide storage tank (10) is -20 degrees Celsius and the pressure is 2 MPa.

5. The carbon dioxide purification, delivery, and injection system for EOR oil displacement according to claim 3, characterized in that, The conveying module (S2) also includes an venting riser (15).

6. The carbon dioxide purification, delivery, and injection system for EOR oil displacement according to claim 3, characterized in that, The preset pressure of the booster pump (16) is 8.1 MPa.

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