Carbon dioxide gasification pressurized liquid supply system and liquid supply method

Abstract

The present invention provides a carbon dioxide gasification pressurized liquid supply system and a liquid supply method, the system includes a carbon dioxide storage tank I, a carbon dioxide gasification pressurized device, a buffer tank, a fracturing truck, a wellhead and an instrument truck, the carbon dioxide storage tank I is connected to the carbon dioxide gasification pressurized device, the outlet of the carbon dioxide gasification pressurized device is connected to a carbon dioxide storage device, the outlet of the carbon dioxide storage device is connected to the inlet of the buffer tank, and the buffer tank is connected to the wellhead through the fracturing truck; the instrument truck is electrically connected to the control cabinet in the carbon dioxide gasification pressurized device. The present invention uses gaseous carbon dioxide to displace the liquid carbon dioxide in the carbon dioxide storage tank II, so that the fracturing truck can obtain continuous and stable liquid supply. The present invention adds a buffer tank between the fracturing truck and the carbon dioxide storage tank II. During the construction process, all the carbon dioxide in the carbon dioxide storage tank II first enters the buffer tank, and the buffer tank is used to supply liquid to multiple construction equipment at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a carbon dioxide gasification pressurized liquid supply system and a liquid supply method. Background Art

[0002] As a new waterless fracturing technology, carbon dioxide fracturing technology has good adaptability to highly water-sensitive, strongly water-locking and unconventional oil and gas reservoirs, eliminates reservoir water sensitivity and water-locking damage, and improves the fracturing transformation effect; the fracturing fluid has no residue, can protect the reservoir and support cracks; it can achieve autonomous and rapid flowback, which can greatly increase the production of a single well.

[0003] In the application of carbon dioxide fracturing technology, conventional carbon dioxide storage tanks and carbon dioxide booster pump trucks are used as the fluid supply combination equipment of the fracturing truck. This fluid supply method has the following problems:

[0004] (1) During the construction process, the suction effect of the booster pump truck and the friction of the pipeline cause the liquid CO2 in the ground supply pipeline to partially gasify, resulting in the fracturing truck running out of pump. If carbon dioxide dry fracturing with sand is carried out, the displacement is difficult to increase and is extremely unstable. The sand ratio and the amount of sand added cannot meet the construction design requirements, which is easy to cause sand blockage.

[0005] (2) Due to the influence of pipeline friction, the speed at which the liquid level in the carbon dioxide storage tanks drops is inconsistent. If the liquid carbon dioxide in one or more of the storage tanks is used up prematurely, gas will enter the liquid supply pipeline, causing the fracturing truck to run out of pumps. Summary of the invention

[0006] In order to overcome the problems of empty pump, discontinuous and unstable liquid supply, and inconsistent drop in liquid level in the storage tank caused by gasification of liquid carbon dioxide due to suction of the fracturing truck in the existing process of transporting liquid carbon dioxide from a storage tank to a fracturing truck, the present invention provides a carbon dioxide gasification pressurized liquid supply system and a liquid supply method. The present invention supplies liquid to multiple construction equipment at the same time through a buffer tank, thereby solving the problem of difference in displacement between different construction equipment. At the same time, the liquid supply in the present invention is continuous and stable.

[0007] The technical solution adopted by the present invention is:

[0008] A carbon dioxide gasification pressurized liquid supply system comprises a carbon dioxide storage tank I, a carbon dioxide gasification pressurized device, a buffer tank, a fracturing vehicle, a wellhead and an instrument vehicle, wherein the carbon dioxide storage tank I is connected to the carbon dioxide gasification pressurized device, the outlet of the carbon dioxide gasification pressurized device is connected to the carbon dioxide storage device, the outlet of the carbon dioxide storage device is connected to the inlet of the buffer tank, and the buffer tank is connected to the wellhead through the fracturing vehicle; the instrument vehicle is electrically connected to a control cabinet in the carbon dioxide gasification pressurized device.

[0009] The control cabinet is connected to the instrument vehicle via a signal cable electrical signal.

[0010] The carbon dioxide storage tank I is provided with a liquid level gauge I, the lower outlet of the carbon dioxide storage tank I is provided with an outlet electric valve, and one side of the upper part of the carbon dioxide storage tank I is provided with a pressure sensor I; the outlet electric valve, liquid level gauge I and pressure sensor I are respectively connected to the electrical signal of the control cabinet in the carbon dioxide gasification and boosting device.

[0011] The outlet of the buffer tank is connected to the inlet manifold of the fracturing vehicle, and the outlet manifold of the fracturing vehicle is connected to the wellhead; a wellhead end opening valve is arranged between the outlet manifold and the wellhead.

[0012] The buffer tank is connected to the outlet manifold of the fracturing vehicle through a cooling return pipeline, and a cooling valve is arranged on the cooling return pipeline.

[0013] The carbon dioxide storage device includes multiple carbon dioxide storage tanks II, which are arranged in parallel; each carbon dioxide storage tank II is provided with a pressure regulating valve, a liquid level gauge II, a pressure sensor II and a flow regulating valve; the pressure regulating valve is arranged at the wellhead at the top of the carbon dioxide storage tank II, the pressure sensor II is arranged on one side of the upper part of the carbon dioxide storage tank II, and the flow regulating valve is arranged at the bottom outlet of the carbon dioxide storage tank II.

[0014] The outlets of the plurality of carbon dioxide storage tanks II are connected in parallel to the buffer tank via a liquid phase booster manifold.

[0015] The carbon dioxide gasification and pressurization device is connected to the carbon dioxide storage device through a gas phase pressurization pipeline.

[0016] A method for gasifying, pressurizing and supplying carbon dioxide comprises the following steps:

[0017] Step 1: The carbon dioxide in the carbon dioxide storage tank I is pressurized and gasified by the carbon dioxide gasification and pressurization device and then enters multiple carbon dioxide storage tanks II through the gas phase pressurization manifold, and the liquid carbon dioxide in the multiple carbon dioxide storage tanks II enters the buffer tank through the liquid phase pressurization manifold;

[0018] Step 2: The instrument vehicle displays the liquid level and pressure values ​​of the carbon dioxide storage tank I, multiple carbon dioxide storage tanks II and the buffer tank in real time, and determines the opening of the pressure regulating valve according to the set boost pressure to ensure that the pressure in the carbon dioxide storage tank II is stable within the required range;

[0019] Step 3: According to the liquid level of each carbon dioxide storage tank II collected by the control cabinet, adjust the opening of the flow control valve corresponding to each carbon dioxide storage tank II to ensure that the liquid level of all carbon dioxide storage tanks II drops synchronously to prevent the gas phase from entering the liquid phase booster manifold;

[0020] Step 4: The control cabinet collects the liquid level value of the buffer tank, and adjusts the opening of the inlet flow control valve according to the preset value of the liquid level to keep the liquid level of the buffer tank 14 stable, so as to continuously and stably supply liquid to the fracturing truck.

[0021] In the step 1, the critical state carbon dioxide in the carbon dioxide storage tank I is pressurized and gasified by the carbon dioxide gasification and boosting device, and the pressure increases from P1 to P2. Then the pressurized gaseous carbon dioxide enters the carbon dioxide storage device through the gas phase boosting manifold, so that the liquid carbon dioxide in the carbon dioxide storage device is in a supercritical state, and at the same time, the liquid carbon dioxide in the carbon dioxide storage device is displaced through the liquid phase boosting manifold to the buffer tank.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention pressurizes and gasifies the liquid carbon dioxide in the carbon dioxide storage tank I, so that the liquid carbon dioxide in the critical state in the carbon dioxide storage tank I is in a supercritical state, thereby preventing the fracturing truck from running out of pump due to gasification during the process of transporting the liquid carbon dioxide from the carbon dioxide storage tank II to the fracturing truck.

[0024] (2) The present invention uses gaseous carbon dioxide to displace the liquid carbon dioxide in the carbon dioxide storage tank II, so that the fracturing truck can obtain continuous and stable liquid supply.

[0025] (3) The present invention adds a buffer tank between the fracturing truck and the carbon dioxide storage tank II. During the construction process, all the carbon dioxide in the carbon dioxide storage tank II first enters the buffer tank, and the buffer tank is used to supply liquid to multiple construction equipment at the same time to solve the problem of different displacement sizes between different construction equipment.

[0026] (4) The present invention establishes a cooling reflux pipeline between the outlet manifold and the buffer tank of the fracturing truck, which can realize the recycling of liquid carbon dioxide in the pipeline and the fracturing truck cooling stage during the construction process, thereby reducing emissions.

[0027] The following is a further description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a system flow chart of the present invention.

[0029] In the figure, the reference numerals are: 1, liquid level gauge I; 2, carbon dioxide storage tank I; 3, pressure sensor I; 4, outlet electric valve; 5, carbon dioxide gasification booster device; 6, gas phase booster manifold; 7, pressure regulating valve; 8, liquid level gauge II; 9, pressure sensor II; 10, carbon dioxide storage tank II; 11, flow regulating valve; 12, buffer tank liquid level gauge; 13, buffer tank pressure sensor; 14, buffer tank; 15, inlet flow regulating valve; 16, fracturing vehicle inlet manifold; 17, fracturing vehicle; 18 fracturing vehicle outlet manifold; 19, cooling valve; 20, cooling return pipeline; 21, wellhead switch valve; 22, wellhead; 23, liquid phase booster manifold; 24, instrument vehicle; 25, control cabinet; 26, signal cable. DETAILED DESCRIPTION

[0030] Embodiment 1:

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In order to overcome the problems of the existing process of transporting liquid carbon dioxide from a storage tank to a fracturing truck, in which the liquid carbon dioxide is gasified due to the suction of the fracturing truck, resulting in an empty pump, discontinuous and unstable liquid supply, and inconsistent drop in the liquid level of the storage tank, the present invention provides a method as follows Figure 1 A carbon dioxide gasification pressurized liquid supply system and liquid supply method are shown. The present invention supplies liquid to multiple construction equipment simultaneously through a buffer tank, thereby solving the problem of different displacement sizes between different construction equipment. At the same time, the liquid supply in the present invention is continuous and stable.

[0033] A carbon dioxide gasification pressurized liquid supply system comprises a carbon dioxide storage tank Ⅰ2, a carbon dioxide gasification pressurizing device 5, a buffer tank 14, a fracturing vehicle 17, a wellhead 22 and an instrument vehicle 24, wherein the carbon dioxide storage tank Ⅰ2 is connected to the carbon dioxide gasification pressurizing device 5, the outlet of the carbon dioxide gasification pressurizing device 5 is connected to a carbon dioxide storage device, the outlet of the carbon dioxide storage device is connected to an inlet of the buffer tank 14, and the buffer tank 14 is connected to the wellhead 22 via the fracturing vehicle 17; the instrument vehicle 24 is electrically connected to a control cabinet 25 in the carbon dioxide gasification pressurizing device 5.

[0034] In the present invention, the carbon dioxide in the carbon dioxide storage tank Ⅰ2 is pressurized and gasified by the carbon dioxide gasification and pressurization device 5. The gaseous carbon dioxide is prevented from entering the subsequent process. The present invention provides stable energized carbon dioxide gas through the carbon dioxide gasification and pressurization device 5, so that the critical liquid carbon dioxide in the carbon dioxide storage tank Ⅱ10 is in a supercritical state, and the fracturing truck 17 is prevented from running out of pump due to gasification.

[0035] In the present invention, the instrument vehicle 24, the carbon dioxide gasification and pressurization device 5 and the control cabinet 25 are all existing devices and will not be further described in the present invention.

[0036] Embodiment 2:

[0037] Based on Example 1, in this example, preferably, a control cabinet 25 is provided in the carbon dioxide gasification and pressurization device 5 , and the control cabinet 25 is electrically connected to the instrument vehicle 24 via a signal cable 26 .

[0038] Preferably, a liquid level gauge Ⅰ1 is provided on the carbon dioxide storage tank Ⅰ2, an outlet electric valve 4 is provided at the lower outlet of the carbon dioxide storage tank Ⅰ2, and a pressure sensor Ⅰ3 is provided on one side of the upper part of the carbon dioxide storage tank Ⅰ2; the outlet electric valve 4, liquid level gauge Ⅰ1 and pressure sensor Ⅰ3 are respectively connected to the control cabinet 25 in the carbon dioxide gasification booster device 5 with electrical signals.

[0039] Preferably, the outlet of the buffer tank 14 is connected to the inlet manifold 16 of the fracturing vehicle 17 , and the outlet manifold 18 of the fracturing vehicle 17 is connected to the wellhead 22 ; a wellhead end opening valve 21 is provided between the outlet manifold 18 and the wellhead 22 .

[0040] Preferably, the buffer tank 14 is connected to the outlet manifold 18 of the fracturing vehicle 17 via a cooling return pipeline 20 , and a cooling valve 19 is provided on the cooling return pipeline 20 .

[0041] In the present invention, the buffer tank 14 is connected to the outlet manifold 18 of the fracturing vehicle through a cooling return pipeline 20, which is controlled by a cooling valve 19. During the cold pump stage of on-site construction, the wellhead switch valve 21 is closed and the cooling valve is opened, and a loop is established between the outlet manifold 18 of the fracturing vehicle and the buffer tank 14, so that the recycling of liquid carbon dioxide can be achieved during the construction process, reducing emissions, and at the same time, it can play a role in circulating gas-liquid separation and increase the cold pump speed.

[0042] Preferably, the carbon dioxide storage device includes multiple carbon dioxide storage tanks II10, and the multiple carbon dioxide storage tanks II10 are arranged in parallel; each carbon dioxide storage tank II10 is provided with a pressure regulating valve 7, a liquid level gauge II8, a pressure sensor II9 and a flow regulating valve 11; the pressure regulating valve 7 is arranged at the wellhead at the top of the carbon dioxide storage tank II10, the pressure sensor II9 is ​​arranged on one side of the upper part of the carbon dioxide storage tank II10, and the flow regulating valve 11 is arranged at the bottom outlet of the carbon dioxide storage tank II10.

[0043] Preferably, the outlets of the plurality of carbon dioxide storage tanks II 10 are connected in parallel and then connected to the buffer tank 14 via a liquid phase booster manifold 23 .

[0044] Preferably, the carbon dioxide gasification and pressurization device 5 is connected to the carbon dioxide storage device through a gas phase pressurization pipeline 6 .

[0045] like Figure 1 As shown, during on-site construction of the present invention, the carbon dioxide storage tank Ⅰ2 is connected to the carbon dioxide gasification and boosting device 5, the outlet of the carbon dioxide gasification and boosting device 5 is connected to the carbon dioxide storage tank Ⅱ10 through the gas phase boosting manifold 6, and the outlets of multiple carbon dioxide storage tanks Ⅱ10 are connected in parallel and connected to the buffer tank 14 through the liquid phase boosting manifold 23. The buffer tank 14 is connected to the fracturing truck 17 through the fracturing truck inlet manifold 16, and the fracturing truck outlet manifold 18 is connected in parallel to the wellhead 22 through the wellhead end switch valve 21.

[0046] In the present invention, the level gauge Ⅰ1, the pressure sensor Ⅰ3, the outlet electric valve 4, the level gauge Ⅱ8, the pressure sensor Ⅱ9, the pressure regulating valve 7, the flow regulating valve 11, the buffer tank level gauge 12, the buffer tank pressure sensor 13, and the inlet flow regulating valve 15 are respectively connected to the control cabinet 25 by electrical signals, and the control cabinet 25 is connected to the instrument vehicle 24 through a signal cable 26. The control cabinet 25 collects the pressure and liquid level values ​​of the carbon dioxide storage tank Ⅰ2, the carbon dioxide storage tank Ⅱ10, and the buffer tank 14, and transmits them to the instrument vehicle 24 to realize centralized display and control of parameters.

[0047] Embodiment 3:

[0048] Based on Example 1 or 2, this embodiment provides a method for gasifying, pressurizing and supplying carbon dioxide, including the following steps:

[0049] Step 1: The carbon dioxide in the carbon dioxide storage tank Ⅰ2 is pressurized and gasified by the carbon dioxide gasification and pressurization device 5 and then enters the multiple carbon dioxide storage tanks Ⅱ10 through the gas phase pressurization manifold 6. The liquid carbon dioxide in the multiple carbon dioxide storage tanks Ⅱ10 enters the buffer tank 14 through the liquid phase pressurization manifold 23;

[0050] Step 2: The instrument vehicle 24 displays the liquid level and pressure values ​​of the carbon dioxide storage tank Ⅰ2, the plurality of carbon dioxide storage tanks Ⅱ10 and the buffer tank 14 in real time, and determines the opening of the pressure regulating valve 7 according to the set boost pressure to ensure that the pressure in the carbon dioxide storage tank Ⅱ10 is stable within the required range;

[0051] Step three, according to the liquid level of each carbon dioxide storage tank II 10 collected by the control cabinet 25, adjust the opening of the flow control valve 11 corresponding to each carbon dioxide storage tank II 10 to ensure that the liquid level of all carbon dioxide storage tanks II 10 drops synchronously to prevent the gas phase from entering the liquid phase booster manifold 23;

[0052] Step 4: The control cabinet 25 collects the liquid level value of the buffer tank 14 and adjusts the opening of the inlet flow control valve 15 according to the preset value of the liquid level to keep the liquid level of the buffer tank 14 stable and provide continuous and stable liquid supply to the fracturing truck 17.

[0053] During the on-site construction process, the present invention provides stable energized carbon dioxide gas through the carbon dioxide gasification and pressurization device 5, so that the critical liquid carbon dioxide in the carbon dioxide storage tank II 10 is in a supercritical state, and at the same time, the liquid carbon dioxide in the carbon dioxide storage tank II 10 is displaced through the liquid phase pressurization manifold 23 to the buffer tank 14, which can effectively prevent the fracturing truck 17 from sucking and causing gasification and empty pumping during the transportation of liquid carbon dioxide.

[0054] In the present invention, the control cabinet 25 automatically adjusts the opening of the pressure regulating valve 7 based on the carbon dioxide storage tank II 10 with the largest pressure value, so that the pressure of each carbon dioxide storage tank II 10 is stabilized within a certain range, and the liquid carbon dioxide in the carbon dioxide storage tank II 10 is displaced, so that the fracturing truck can obtain continuous and stable liquid supply. The liquid supply system can adjust the liquid discharge speed of each carbon dioxide storage tank II by adjusting the opening of the flow regulating valve 11 according to the calculation and comparison of the collected data, ensure the synchronous decrease of the liquid level, prevent the gas from entering the liquid phase booster manifold 23, and cause the fracturing truck 17 to run out of pump, so as to achieve continuous and balanced liquid supply.

[0055] In the present invention, the control cabinet 25 collects the liquid level value of the buffer tank 14, and automatically adjusts the opening of the inlet flow control valve 15 based on the set value, so that the liquid level of the buffer tank 14 remains stable, thereby achieving a more reliable flow distribution problem among multi-pipeline construction equipment.

[0056] The specific implementation process of the present invention is:

[0057] The critical state carbon dioxide in the carbon dioxide storage tank Ⅰ2 is pressurized and gasified by the carbon dioxide gasification and pressurization device 5, and the pressure increases from P1 to P2. Then the pressurized gaseous carbon dioxide enters the carbon dioxide storage tank Ⅱ10 through the gas phase pressurization manifold 6, so that the liquid carbon dioxide in the carbon dioxide storage tank Ⅱ10 is in a supercritical state, and at the same time, the liquid carbon dioxide in the carbon dioxide storage tank Ⅱ10 is displaced through the liquid phase pressurization manifold 23 to the buffer tank 14, which can effectively prevent the fracturing truck 17 from sucking and causing gasification and empty pumping during the transportation of liquid carbon dioxide. During the on-site construction process, the instrument vehicle 24 displays the liquid level and pressure values ​​of the carbon dioxide storage tank Ⅰ2, the carbon dioxide storage tank Ⅱ10, and the buffer tank 14 in real time, and automatically calculates and adjusts the opening of the pressure regulating valve 7 according to the set boost pressure to ensure the stability of the boost pressure; automatically adjusts the opening of the flow regulating valve 11 to ensure that the liquid levels of all carbon dioxide storage tanks Ⅱ10 drop synchronously to prevent the liquid carbon dioxide in one or more carbon dioxide storage tanks Ⅱ10 from being exhausted prematurely, causing the gas phase to enter the liquid phase booster manifold 23, causing the fracturing truck 17 to run out of pump; automatically adjusts the opening of the inlet flow regulating valve 15 to keep the liquid level of the buffer tank 14 stable, thereby achieving stable, continuous and balanced liquid supply.

[0058] The present invention pressurizes and gasifies liquid carbon dioxide, so that the critical liquid carbon dioxide in the carbon dioxide storage tank II 10 is in a supercritical state, thereby preventing the fracturing truck from running out of pump due to gasification during the process of transporting the liquid carbon dioxide from the carbon dioxide storage tank II 10 to the fracturing truck 17.

[0059] The present invention uses gaseous carbon dioxide to displace liquid carbon dioxide in the storage tank, so that the fracturing vehicle 17 can obtain continuous and stable liquid supply.

[0060] The present invention adds a buffer tank 14 between the fracturing truck 17 and the carbon dioxide storage tank II 10. During the construction process, all the carbon dioxide in the carbon dioxide storage tank II 10 first enters the buffer tank 14, and the buffer tank 14 is used to supply liquid to multiple construction equipment at the same time to solve the problem of different displacement sizes between different construction equipment.

[0061] The present invention establishes a cooling reflux pipeline 20 between the outlet manifold 18 of the fracturing vehicle 17 and the buffer tank 14, so as to realize the recycling of liquid carbon dioxide in the pipeline and the fracturing vehicle cooling stage during the construction process and reduce emissions.

[0062] The present invention automatically controls the boost pressure of the carbon dioxide storage tank Ⅰ2 and the liquid discharge speed of the carbon dioxide storage tank Ⅱ10 through the control cabinet 25, ensuring that the liquid level of each carbon dioxide storage tank Ⅱ10 drops synchronously during the construction process, storing stable liquid supply. The present invention controls the liquid level of the buffer tank 14 to provide reliable liquid supply capacity for multi-pipeline construction.

[0063] The above is only a preferred embodiment of the present invention. The present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention. The device structure and method steps not described in detail in the present invention are all prior art and will not be further described in the present invention.

Claims

1. A carbon dioxide gasification pressurized liquid supply system, characterized in that: The invention comprises a carbon dioxide storage tank I (2), a carbon dioxide gasification and pressurizing device (5), a buffer tank (14), a fracturing vehicle (17), a wellhead (22) and an instrument vehicle (24), wherein the carbon dioxide storage tank I (2) is connected to the carbon dioxide gasification and pressurizing device (5), the outlet of the carbon dioxide gasification and pressurizing device (5) is connected to a carbon dioxide storage device, the outlet of the carbon dioxide storage device is connected to the inlet of the buffer tank (14), and the buffer tank (14) is connected to the wellhead (22) through the fracturing vehicle (17); the instrument vehicle (24) is electrically connected to a control cabinet (25) in the carbon dioxide gasification and pressurizing device (5); the carbon dioxide storage device comprises a plurality of carbon dioxide storage tanks II (10), a plurality of carbon dioxide storage tanks II (10) are arranged in parallel; each carbon dioxide storage tank II (10) is provided with a pressure regulating valve (7), a liquid level gauge II (8), a pressure sensor II (9) and a flow regulating valve (11); the pressure regulating valve (7) is arranged at the top opening of the carbon dioxide storage tank II (10), the pressure sensor II (9) is arranged on one side of the upper part of the carbon dioxide storage tank II (10), and the flow regulating valve (11) is arranged at the bottom outlet of the carbon dioxide storage tank II (10); the outlets of the plurality of carbon dioxide storage tanks II (10) are connected in parallel to the buffer tank (14) through a liquid phase boosting manifold (23); the carbon dioxide gasification boosting device (5) is connected to the carbon dioxide storage device through a gas phase boosting manifold (6).

2. A carbon dioxide gasification pressurized liquid supply system according to claim 1, characterized in that: The control cabinet (25) is electrically connected to the instrument vehicle (24) via a signal cable (26).

3. The carbon dioxide gasification pressurized liquid supply system according to claim 1, characterized in that: The carbon dioxide storage tank I (2) is provided with a liquid level gauge I (1), the lower outlet of the carbon dioxide storage tank I (2) is provided with an outlet electric valve (4), and the upper side of the carbon dioxide storage tank I (2) is provided with a pressure sensor I (3); the outlet electric valve (4), the liquid level gauge I (1) and the pressure sensor I (3) are respectively connected to the control cabinet (25) in the carbon dioxide gasification and pressurization device (5) by electrical signals.

4. The carbon dioxide gasification pressurized liquid supply system according to claim 1, characterized in that: The outlet of the buffer tank (14) is connected to the inlet manifold (16) of the fracturing vehicle (17), and the outlet manifold (18) of the fracturing vehicle (17) is connected to the wellhead (22); a wellhead end opening valve (21) is provided between the outlet manifold (18) and the wellhead (22).

5. The carbon dioxide gasification pressurized liquid supply system according to claim 1, characterized in that: The buffer tank (14) is connected to the outlet manifold (18) of the fracturing vehicle (17) via a cooling return pipeline (20), and a cooling valve (19) is provided on the cooling return pipeline (20).

6. A liquid supply method for a carbon dioxide gasification pressurized liquid supply system according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: The carbon dioxide in the carbon dioxide storage tank I (2) is pressurized and gasified by the carbon dioxide gasification and pressurization device (5) and then enters the plurality of carbon dioxide storage tanks II (10) through the gas phase pressurization manifold (6); the liquid carbon dioxide in the plurality of carbon dioxide storage tanks II (10) enters the buffer tank (14) through the liquid phase pressurization manifold (23); Step 2: the instrument vehicle (24) displays the liquid level and pressure values ​​of the carbon dioxide storage tank I (2), the plurality of carbon dioxide storage tanks II (10) and the buffer tank (14) in real time, and adjusts the opening of the pressure regulating valve (7) according to the set boost pressure to ensure that the pressure in the carbon dioxide storage tank II (10) is stable within the required range; Step 3: According to the liquid level of each carbon dioxide storage tank II (10) collected by the control cabinet (25), the opening of the flow control valve (11) corresponding to each carbon dioxide storage tank II (10) is adjusted to ensure that the liquid level of all carbon dioxide storage tanks II (10) drops synchronously to prevent the gas phase from entering the liquid phase booster manifold (23); Step 4: The control cabinet (25) collects the liquid level value of the buffer tank (14), and adjusts the opening of the inlet flow control valve (15) according to the preset value of the liquid level, so that the liquid level of the buffer tank (14) remains stable, thereby continuously and stably supplying liquid to the fracturing vehicle (17).

7. The liquid supply method according to claim 6, characterized in that: In the step 1, the critical carbon dioxide in the carbon dioxide storage tank I (2) is pressurized and gasified by the carbon dioxide gasification and pressurization device (5), and the pressure is increased from P1 to P2. Then, the pressurized gaseous carbon dioxide enters the carbon dioxide storage device through the gaseous phase pressurization manifold (6), so that the liquid carbon dioxide in the carbon dioxide storage device is in a supercritical state, and at the same time, the liquid carbon dioxide in the carbon dioxide storage device is displaced through the liquid phase pressurization manifold (23) to the buffer tank (14).

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