A special pump sled for carbon dioxide huff and puff stimulation of oil and gas wells

Abstract

A special pump sled for carbon dioxide huff and puff pressure boosting of oil and gas well relates to the technical field of carbon dioxide flooding oil, and the device adopts a sled-mounted base to integrate an injection system composed of a storage tank, double injection tanks, an injection pump, a liquid supplement pump and a three-way reversing valve. A separation bag A is arranged in the storage tank to divide the space into a liquid CO2 storage area and a pressure regulating area, and the storage tank pressure is regulated through a charging and discharging medium. The double injection tanks realize an alternating working mode through the three-way reversing valve A / B: when the injection pump pressurizes and injects CO2 into one injection tank through the three-way valve A, the liquid supplement pump synchronously supplements liquid CO2 to the other injection tank through the three-way valve B. The structure makes liquid CO2 not contact the injection pump throughout, completely eliminates the gas blockage phenomenon, and guarantees the stability of pump efficiency. The unique separation bag pressure compensation mechanism cooperates with the three-way valve group to realize constant storage tank pressure and continuous and controllable injection flow, solves the problems of pressure fluctuation and pumping interruption caused by phase change of traditional equipment, and significantly improves the CO2 injection efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of carbon dioxide flooding oil, and particularly relates to a special pump sled for carbon dioxide huff and puff pressure boosting of oil and gas wells. BACKGROUND

[0002] Carbon dioxide huff and puff oil displacement technology is one of the specific application forms of carbon dioxide flooding oil technology. The carbon dioxide huff and puff oil displacement technology is an enhanced oil recovery technology, which injects liquid carbon dioxide into an oil layer under a certain pressure, so that the liquid carbon dioxide is miscible with the formation crude oil, the viscosity of the crude oil is reduced, the formation plugging problem is solved, and the formation energy is supplemented by using the expansion of carbon dioxide, so that the oil well recovery is improved.

[0003] The main structure of the existing carbon dioxide huff and puff oil displacement pump sled includes a carbon dioxide injection system and a carbon dioxide recovery system, wherein the carbon dioxide injection system includes a storage tank, a liquid feeding pump, an injection pipeline, an injection pump and the like. In order to avoid the gasification of liquid carbon dioxide in the injection pipeline and the injection pump, the injection pipeline and the injection pump need to be pre-cooled. The injection pump used in the prior art is mostly a plunger pump (because the plunger pump can provide a higher working pressure). The plunger pump generates heat continuously during the working process (heat generated by friction between the plunger and the cylinder). The heat makes a small amount of the liquid carbon dioxide gasify. The gasified carbon dioxide is in the cylinder, which reduces the pump efficiency (actual output flow rate and theoretical output flow rate) and the pumping pressure (discharge pressure of the pump) on the one hand. In order to avoid the temperature rise of the plunger pump, a refrigeration system is usually arranged on the structure of the plunger pump in the prior art. The refrigeration system is used for cooling the plunger pump. However, such a setting makes the structure of the plunger pump more complex and the maintenance more inconvenient.

[0004] In addition, the storage tank is used for storing liquid carbon dioxide. In order to ensure that the liquid carbon dioxide can be stored at room temperature, the pressure in the storage tank needs to be maintained at 2.2-2.5 Mpa (a decrease in pressure will cause the gasification of liquid carbon dioxide). As the liquid carbon dioxide continuously flows out of the storage tank, the pressure in the storage tank decreases. In order to continue to maintain the pressure of 2.2-2.5 Mpa, the existing technology has to supplement gas (carbon dioxide gas) into the storage tank many times. The defects of supplementing gas are as follows: first, a special filling equipment needs to be used; second, because the gas is compressible, a large amount of carbon dioxide is needed for supplementing, and the carbon dioxide gas supplemented into the storage tank is finally discharged into the atmosphere, causing pollution. SUMMARY

[0005] To solve the two defects mentioned in the background art, the present application provides a special pump sled for oil and gas well stimulation carbon dioxide throughput pressurization. The injection pump of the present application is not directly used for pumping liquid carbon dioxide, thereby avoiding the gasification of carbon dioxide by the heat of the pump work, and avoiding the adverse effects of gas on pump efficiency and pumping pressure. In the carbon dioxide filling stage of the present application, the remaining space of the storage tank is supplemented by the separation bag A, the gas or liquid is injected in the separation bag A, and the pressure in the storage tank is balanced by the release of the gas or liquid in the separation bag A. In the injection stage, the outflow of liquid carbon dioxide in the storage tank is almost balanced with the inflow of water, thereby ensuring the stability of the pressure in the storage tank in the injection stage, and further ensuring the stability of the state of carbon dioxide, which is conducive to the normal work of the whole pump sled.

[0006] The technical scheme provided by the application is as follows: a special pump sled for carbon dioxide huff and puff pressure boosting of oil and gas well, comprising a base, wherein an injection system is arranged on the base; the injection system comprises a storage tank, injection tanks, an injection pump, a liquid supplement pump, three-way reversing valves A, B and C; flanges A are arranged at two ends of the storage tank, a separation bag A is arranged in the storage tank, two ends of the separation bag A are fixedly connected with the flanges A, liquid or gas can be injected into the separation bag A through the flanges A, a liquid filling port is arranged above the storage tank, liquid carbon dioxide is injected into the storage tank and the space outside the separation bag A through the liquid filling port, and the separation bag A has the function of separating liquid; during the liquid carbon dioxide filling stage, air or water is filled in the separation bag A, when the carbon dioxide liquid in the storage tank expands in volume due to temperature rise or pressure change, the pressure in the storage tank can be reduced by releasing the air or water in the separation bag A, and therefore the problem of discharging carbon dioxide into the air is avoided; the injection tanks are two, referred to as a first injection tank and a second injection tank, flanges B are arranged at two ends of the injection tanks, a separation bag B is arranged in the injection tanks, the separation bag B is used for separating two liquids, and two ends of the separation bag B are fixedly connected with the flanges B; each three-way reversing valve has one main port and two branch ports, the two branch ports are connected with the main port through reversing to realize the connection of one branch port with the main port and the disconnection of the other branch port with the main port; the first injection tank is communicated with the lower part of the storage tank through a pipeline, a one-way valve A is arranged on the pipeline, the first injection tank is also communicated with a branch port of the three-way reversing valve C, the second injection tank is communicated with the storage tank through a pipeline, a one-way valve B is arranged on the pipeline, the second injection tank is also communicated with a branch port of the three-way reversing valve C, the main port of the three-way reversing valve C is connected with a well head, the outlet end of the injection pump is connected with the main port of the three-way reversing valve A, the two branch ports of the three-way reversing valve A are connected with one flange B of the first injection tank and one flange B of the second injection tank, the other flange B of the first injection tank is connected with a branch port of the three-way reversing valve B through a pipeline, and a constant pressure opening valve A and a one-way valve C are arranged on the pipeline, the other flange B of the second injection tank is connected with a branch port of the three-way reversing valve B through a pipeline, and a constant pressure opening valve B and a one-way valve D are arranged on the pipeline, the main port of the three-way reversing valve B is connected with the inlet end of the liquid supplement pump, and the outlet end of the liquid supplement pump is connected with one flange A of the storage tank through a pipeline and a one-way valve E is arranged on the pipeline; the liquid carbon dioxide does not directly contact the injection pump, so that the injection pump will not be gas blocked, and the pump efficiency and the pumping pressure of the injection pump will not be adversely affected. At the same time, during the carbon dioxide injection stage, the real-time outflow of the carbon dioxide in the storage tank is almost the same as the real-time injection of water, so that the pressure in the storage tank is stable.

[0007] The further technical scheme is that a balance tank is arranged on the pipeline upstream of the branch port of the three-way reversing valve B. The balance tank is filled with liquid to ensure that there is liquid at the inlet end of the liquid supplement pump at the initial stage of work.

[0008] Further technical solutions are: the upper end of the injection tank is connected with an exhaust pipe, and an exhaust valve is installed on the exhaust pipe; the gas in the injection tank is discharged through the exhaust valve.

[0009] Further technical solutions are: a flow sensor, a temperature sensor and a switch valve A are arranged on the pipeline upstream of the inlet end of the injection pump; a pressure sensor is arranged on the pipeline between the three-way reversing valve A and the two injection tanks; a flow sensor, a temperature sensor, a pressure sensor and a switch valve B are arranged on the pipeline between the liquid supplementing pump and the flange A; a flow sensor, a temperature sensor, a pressure sensor and a switch valve C are arranged on the pipeline between the three-way reversing valve C and the wellhead.

[0010] Further technical solutions are: the separation bag B passes through the hole in the center of the flange B, a supporting sleeve is arranged in the central hole of the neck of the flange B, the supporting sleeve is located in the interior of the separation bag B and is used to support the separation bag B from the inside, a pressing sleeve is arranged in the central hole at the port of the flange B, and the pressing sleeve is used to firmly press the end of the separation bag B on the flange B, and the pressing sleeve and the supporting sleeve are connected through threads.

[0011] Compared with the prior art, the beneficial effects of the present application are:

[0012] 1. The prior art, taking a common 20 cubic meter carbon dioxide storage tank as an example, the filling capacity generally should not exceed 15 cubic meters, a certain space is reserved to prevent the volume expansion of carbon dioxide liquid when the temperature rises or the pressure changes, resulting in overpressure of the storage tank. As can be seen, the prior art storage tank leaves at least 5 cubic meters for filling carbon dioxide gas, and the carbon dioxide in the super 5 cubic meters is ultimately discharged into the atmosphere, causing greenhouse gas hazards. And this application also takes a common 20 cubic meter carbon dioxide storage tank as an example, and the liquid filling capacity is also not more than 15 cubic meters, and the remaining space is occupied by the separation bag A, and the separation bag A is filled with air or water, and the discharge of the air or water in the separation bag A will not cause environmental pollution. This greatly reduces the use and ultimate discharge of carbon dioxide gas. When the carbon dioxide liquid in the storage tank expands in volume when the temperature rises or the pressure changes, the gas or liquid in the separation bag A is released to reduce the pressure in the storage tank.

[0013] 2. The prior art mostly injects liquid carbon dioxide into the wellhead by using a plunger pump, and the heat generated during the operation of the plunger pump is absorbed by the liquid carbon dioxide, which causes a small amount of liquid carbon dioxide to be gasified, thereby affecting the normal use of the plunger pump. The application adds two injection tanks that work alternately, and the separation bag B in the injection tank is filled with water. The plunger pump increases the hydraulic pressure of water, thereby increasing the hydraulic pressure of liquid carbon dioxide outside the separation bag B, so as to inject the liquid carbon dioxide outside the separation bag B into the wellhead. During the whole injection process of the application, the plunger pump does not directly contact with the liquid carbon dioxide, so the heat generated during the operation of the plunger pump cannot be directly transmitted to the liquid carbon dioxide, and the plunger pump will not cause gas blocking problem, and the pump efficiency and injection efficiency can be ensured.

[0014] 3. In the application, the real-time outflow of liquid carbon dioxide in the storage tank is almost equal to the real-time injection of water into the storage tank, so the pressure in the storage tank is always kept constant, and therefore the state of carbon dioxide in the storage tank is very stable, which is beneficial to the normal operation of the whole pump and pry system. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the structural schematic diagram of the whole application.

[0016] Figure 2 is the structural schematic diagram of the injection tank in the application.

[0017] In the figure: the black thick line is the flow direction of liquid carbon dioxide, and the black thin line is the flow direction of water.

[0018] In the figure: 1, storage tank; 2, separation bag A; 3, flange A; 4, one-way valve A; 5, exhaust valve; 6, first injection tank; 7, flange B; 8, pressure-keeping opening valve A; 9, one-way valve C; 10, on-off valve A; 11, balance tank; 12, three-way reversing valve A; 13, injection pump; 14, three-way reversing valve B; 15, liquid supplementing pump; 16, three-way reversing valve C; 17, on-off valve C; 18, wellhead; 19, one-way valve B; 20, second injection tank; 21, pressure-keeping opening valve B; 22, one-way valve D; 23, on-off valve B; 24, one-way valve E; 25, separation bag B; 26, support sleeve; 27, pressure sleeve; 28, liquid filling port. DETAILED DESCRIPTION

[0019] In order for those skilled in the art to better understand the application scheme, the technical solutions in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the application.

[0020] ReferenceFigure 1 The application discloses a special pump sled for carbon dioxide huff and puff pressure boosting of oil and gas well, which comprises a sled-mounted base, wherein an injection system is arranged on the base, and the injection system comprises a storage tank 1, an injection tank, an injection pump 13, a liquid supplementing pump 15, a three-way reversing valve A 12, a three-way reversing valve B 14 and a three-way reversing valve C 16.

[0021] Flanges A3 are arranged at two ends of the storage tank 1, and a separation bag A2 is arranged in the storage tank 1, the two ends of the separation bag A2 are fixedly connected with the flanges A3, the separation bag A2 divides the storage tank 1 into two independent spaces, liquid or gas can be injected into the separation bag A2 through the flanges A3, a liquid filling port 28 is arranged above the storage tank 1, liquid carbon dioxide can be injected into the space outside the separation bag A2 in the storage tank 1 through the liquid filling port 28, for example, the storage tank 1 has a capacity of 20 cubic meters, the filling amount of the liquid carbon dioxide is not more than 15 cubic meters, and the remaining space is occupied by the separation bag A2, the separation bag A2 has the function of separating liquid; air or water is filled in the separation bag A2, when the liquid carbon dioxide in the storage tank 1 expands in volume due to temperature rise or pressure change, the air or water in the separation bag A2 is released to reduce the internal pressure of the whole storage tank 1, and therefore, the problem that carbon dioxide is discharged into the air is avoided.

[0022] The injection tank has two, two injection tank specifications are the same, in order to facilitate the distinction, respectively referred to as the first injection tank 6 and the second injection tank 20, each injection tank is provided with flange B7 at both ends, the injection tank is provided with a separation bag B25, the separation bag B25 is used for separating two liquids, the two ends of the separation bag B25 are fixedly connected with the flange B7, and the separation bag B25 divides the injection tank into two independent spaces. Each three-way valve has a main port and two branch ports, when the main port is connected with one of the branch ports, the other branch port is in a disconnected state with the main port, and the two branch ports are connected with the main port through the switching action. The first injection tank 6 is communicated with the lower part of the storage tank 1 through a pipeline, and a one-way valve A4 is arranged on the pipeline, and the first injection tank 6 is also communicated with a branch port of the three-way valve C16, the second injection tank 20 is communicated with the lower part of the storage tank 1 through a pipeline, and a one-way valve B19 is arranged on the pipeline, and the second injection tank 20 is also communicated with a branch port of the three-way valve C16, the main port of the three-way valve C16 is connected with the well mouth 18, the outlet end of the injection pump 13 is connected with the main port of the three-way valve A12, the two branch ports of the three-way valve A12 are respectively connected with one of the flanges B7 of the first injection tank 6 and one of the flanges B7 of the second injection tank 20, the other flange B7 of the first injection tank 6 is connected with a branch port of the three-way valve B14 through a pipeline, and a pressure opening valve A8 and a one-way valve C9 are arranged on the pipeline, the other flange B7 of the second injection tank 20 is connected with a branch port of the three-way valve B14 through a pipeline, and a pressure opening valve B21 and a one-way valve D22 are arranged on the pipeline, the main port of the three-way valve B14 is connected with the inlet end of the liquid supplementing pump 15, and the outlet end of the liquid supplementing pump 15 is connected with one of the flanges A3 of the storage tank 1 through a pipeline and is provided with a one-way valve E24. In the present application, liquid carbon dioxide does not directly contact the injection pump 13, so that the injection pump 13 will not be gas blocked, and the pump efficiency and pumping pressure of the injection pump 13 will not be adversely affected. At the same time, in the carbon dioxide injection stage, the real-time flow rate of carbon dioxide in the storage tank 1 is almost the same as the real-time water injection rate into the storage tank 1, so that the pressure in the storage tank 1 is stable.

[0023] In the present application, the injection pump 13 mainly contacts with water, and water will only be gasified at 100 DEG C. Obviously, the temperature generated by the operation of the injection pump 13 cannot gasify water, so the failure rate of the injection pump 13 is low.

[0024] The working process of the present application in the carbon dioxide injection stage is as follows.

[0025] Process one: At this time, the three-way valve A12 is connected with the flange B7 of the first injection tank 6, and disconnected with the flange B7 of the second injection tank 20; the three-way valve B14 is connected with the flange B7 of the second injection tank 20, and disconnected with the flange B7 of the first injection tank 6; the three-way valve C16 is connected with the first injection tank 6, and disconnected with the second injection tank 20. At this time, the pump-out liquid of the injection pump 13 enters the separation bag B25 of the first injection tank 6 through the flange B7, and extrudes the carbon dioxide liquid outside the separation bag B25, so that the carbon dioxide liquid pressure in the first injection tank 6 is increased, and the carbon dioxide liquid reaches the three-way valve C16 through the pipeline, and then enters the wellhead 18 through the switch valve C17. At this time, the pump-out liquid of the liquid supplement pump 15 enters the separation bag A2 of the storage tank 1 through the one-way valve E24, the switch valve B23 and the flange A3, so that the pressure in the storage tank 1 is increased, the carbon dioxide liquid pressure in the storage tank 1 is increased, the carbon dioxide liquid enters the second injection tank 20 through the pipeline, the separation bag B25 in the second injection tank 20 is extruded, and when the liquid pressure exceeds the opening pressure of the constant pressure opening valve B21, the pipeline is opened, and the liquid in the separation bag B25 in the second injection tank 20 enters the balance tank 11 through the constant pressure opening valve B21 and the one-way valve D22.

[0026] Process two: The three three-way valves are simultaneously switched at this time, the three-way valve A12 is connected with the flange B7 of the second injection tank 20, and disconnected with the flange B7 of the first injection tank 6; the three-way valve B14 is connected with the flange B7 of the first injection tank 6, and disconnected with the flange B7 of the second injection tank 20; the three-way valve C16 is connected with the second injection tank 20, and disconnected with the first injection tank 6. At this time, the pump-out liquid of the injection pump 13 enters the separation bag B25 of the second injection tank 20 through the flange B7, and extrudes the carbon dioxide liquid outside the separation bag B25, so that the carbon dioxide liquid pressure in the second injection tank 20 is increased, and the carbon dioxide liquid reaches the three-way valve C16 through the pipeline, and then enters the wellhead 18 through the switch valve C17. At this time, the pump-out liquid of the liquid supplement pump 15 enters the separation bag A2 of the storage tank 1 through the one-way valve E24, the switch valve B23 and the flange A3, so that the pressure in the storage tank 1 is increased, the carbon dioxide liquid pressure in the storage tank 1 is increased, the carbon dioxide liquid enters the first injection tank 6 through the pipeline, (since the pumping pressure of the injection pump 13 is greater than the pumping pressure of the liquid supplement pump 15, the carbon dioxide liquid at this time can only enter the first injection tank 6, and cannot enter the second injection tank 20), the separation bag B25 in the first injection tank 6 is extruded, and when the liquid pressure exceeds the opening pressure of the constant pressure opening valve B21, the pipeline is opened, and the liquid in the separation bag B25 in the first injection tank 6 enters the balance tank 11 through the constant pressure opening valve A8 and the one-way valve C9.

[0027] The "process one" and "process two" of the application work alternately, and the injection pump 13 and the liquid supplement pump 15 work continuously in the alternating working process, so that the carbon dioxide liquid is continuously injected into the well head 18, and the water is continuously injected into the storage tank 1, the unit time pumping amount of the injection pump 13 and the liquid supplement pump 15 is the same, the carbon dioxide outflow amount and the water supplement amount in the storage tank 1 are the same, so that the storage tank 1 maintains a stable pressure state. As can be seen, the storage tank 1 of the application does not need to supplement gas for many times to maintain stable gas pressure, so it does not need to be equipped with professional gas supplement tools on site.

[0028] The balance tank 11 is arranged on the pipeline upstream of the branch port of the three-way reversing valve B14. The balance tank 11 is filled with liquid, which ensures that there is liquid at the inlet end of the liquid supplement pump 15 in the initial stage of work, and there is no problem of dry pumping.

[0029] The upper end of the injection tank is connected with an exhaust pipe, and the exhaust valve 5 is installed on the exhaust pipe; the gas in the injection tank is discharged through the exhaust valve, so as to ensure that there is no gas in the injection tank.

[0030] The flow sensor, the temperature sensor and the on-off valve A10 are arranged on the pipeline upstream of the inlet end of the injection pump 13; the pressure sensor is arranged on the pipeline between the three-way reversing valve A12 and the two injection tanks; the flow sensor, the temperature sensor, the pressure sensor and the on-off valve B23 are arranged on the pipeline between the liquid supplement pump 15 and the flange A3; the flow sensor, the temperature sensor, the pressure sensor and the on-off valve C17 are arranged on the pipeline between the three-way reversing valve C16 and the well head 18. The required data can be known in real time through the flow sensor, the temperature sensor and the pressure sensor, so that the carbon dioxide injection situation is more clear.

[0031] Referring to the drawings Figure 2 The separation bag B25 passes through the hole in the center of the flange B7, the support sleeve 26 is arranged in the central hole of the neck of the flange B7, the support sleeve 26 is located in the inside of the separation bag B25, and is used for supporting and clamping the separation bag B25 between the flange and the support sleeve 26 from the inside, the pressing sleeve 27 is arranged in the central hole at the port of the flange B7, and the pressing sleeve 27 is used for firmly pressing the end of the separation bag B25 on the flange B7, and the pressing sleeve 27 and the support sleeve 26 are connected through threads. Therefore, the separation bag B25 can be fixed on the flange B7, and the sealing is reliable.

[0032] In the application, the separation bag A2 and the separation bag B25 are made of flexible corrosion-resistant waterproof materials, for example, rubber.

[0033] The application discloses a special pump sled for carbon dioxide huff and puff pressure boosting of oil and gas well, belongs to the technical field of carbon dioxide flooding, and is one of efficient oilfield exploitation technical means. The injection system is composed of a sled-mounted base integrated storage tank 1, double injection tanks, an injection pump 13, a liquid supplement pump 15 and a three-way reversing valve. A separation bag A2 is arranged in the storage tank 1 to divide the space into a liquid CO2 storage area and a pressure regulating area, the pressure of the storage tank 1 is regulated through a filling medium, the problem of filling gaseous CO2 is avoided, and CO2 gas emission is reduced. The double injection tanks realize an alternating working mode through a three-way reversing valve A12 and a three-way reversing valve B14. When the injection pump 13 pressurizes and injects CO2 into one injection tank through a three-way valve A, the liquid supplement pump 15 synchronously supplements liquid CO2 into the other injection tank through a three-way valve B, and a three-way valve C realizes continuous and alternating liquid supply of the double tanks to a wellhead 18. The structure makes liquid CO2 not contact the injection pump 13 in the whole process, completely eliminates the gas blockage phenomenon, and guarantees the stability of pump efficiency. The unique separation bag pressure compensation mechanism cooperates with the three-way valve group to realize constant pressure of the storage tank 1 and continuous and controllable injection flow, solves the problems of pressure fluctuation and pumping interruption caused by phase change of traditional equipment, and significantly improves the CO2 injection operation efficiency.

Claims

1. A special pump skid for boosting carbon dioxide production in oil and gas wells, comprising a base, on which an injection system is provided, the injection system comprising a storage tank (1), an injection tank, an injection pump (13), a replenishment pump (15), a three-way reversing valve A (12), a three-way reversing valve B (14), and a three-way reversing valve C (16); flanges A (3) are respectively provided at both ends of the storage tank (1), and a partition bag A (2) is provided inside the storage tank (1), the two ends of the partition bag A (2) are respectively fixedly connected to the flanges A (3), the partition bag A (2) divides the interior of the storage tank (1) into two independent spaces, and can be injected into the partition bag through the flanges A (3). Liquid or gas is injected into the diaphragm bag A (2), and a filling port (28) is provided above the storage tank (1); there are two injection tanks, referred to as the first injection tank (6) and the second injection tank (20), respectively. Flanges B (7) are provided at both ends of the injection tanks, and a diaphragm bag B (25) is provided inside the injection tank. The two ends of the diaphragm bag B (25) are fixedly connected to the flanges B (7), and the diaphragm bag B (25) divides the inside of the injection tank into two independent spaces. The diaphragm bag B (25) is used to separate the two liquids; the first injection tank (6) is connected to the storage tank (1) through a pipeline and a one-way valve A (4) is provided on the pipeline. (6) It is also connected to the branch port of the three-way reversing valve C (16). The second injection tank (20) is connected to the storage tank (1) through a pipeline and a check valve B (19) is installed on the pipeline. The second injection tank (20) is also connected to the branch port of the three-way reversing valve C (16). The main port of the three-way reversing valve C (16) is connected to the wellhead (18). The outlet end of the injection pump (13) is connected to the main port of the three-way reversing valve A (12). The two branch ports of the three-way reversing valve A (12) are respectively connected to one flange B (7) of the first injection tank (6) and one flange B (7) of the second injection tank (20). The first injection... Another flange B (7) of the tank (6) is connected to the branch port of the three-way directional valve B (14) through a pipeline, and a constant pressure opening valve A (8) and a check valve C (9) are installed on the pipeline. Another flange B (7) of the second injection tank (20) is connected to the branch port of the three-way directional valve B (14) through a pipeline, and a constant pressure opening valve B (21) and a check valve D (22) are installed on the pipeline. The main port of the three-way directional valve B (14) is connected to the inlet end of the replenishment pump (15). The outlet end of the replenishment pump (15) is connected to one of the flanges A (3) of the storage tank (1) through a pipeline, and a check valve E (24) is installed on the pipeline. A flow sensor, a temperature sensor, and a switch valve A (10) are installed on the pipeline upstream of the inlet end of the injection pump (13); a pressure sensor is installed on the pipeline between the three-way reversing valve A (12) and the two injection tanks; a flow sensor, a temperature sensor, a pressure sensor, and a switch valve B (23) are installed on the pipeline between the replenishment pump (15) and the flange A (3); a flow sensor, a temperature sensor, a pressure sensor, and a switch valve C (17) are installed on the pipeline between the three-way reversing valve C (16) and the wellhead (18). The separator bag B (25) passes through the hole in the center of the flange B (7). A support sleeve (26) is provided in the central hole of the neck of the flange B (7). The support sleeve (26) is located inside the separator bag B (25) and is used to open the separator bag B (25) from the inside. A pressure sleeve (27) is provided in the central hole at the port of the flange B (7). The pressure sleeve (27) is used to securely press the end of the separator bag B (25) onto the flange B (7). The pressure sleeve (27) and the support sleeve (26) are connected by threads.

2. The special pump skid for carbon dioxide injection and pressurization for enhancing oil and gas well production according to claim 1, characterized in that: A balance tank (11) is installed on the pipeline upstream of the branch port of the three-way reversing valve B (14).

3. A special pump skid for boosting carbon dioxide injection and pressurization in oil and gas wells according to claim 1, characterized in that: The upper end of the injection tank is connected to an exhaust pipe, and an exhaust valve (5) is installed on the exhaust pipe.

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