阅读说明：本技术 一种二氧化碳驱油用的注入设备 (Injection equipment for carbon dioxide flooding ) 是由 崔仕章 侯云福 宋新旺 王黎明 张凤莲 张荣军 曾刚 高琪琪 于 2021-10-18 设计创作，主要内容包括：本发明涉及油田开发领域,公开了一种二氧化碳驱油用的注入设备,包括依次设置的储罐、屏蔽泵、高压泵和注入头,高压泵和注入头之间设置有注入管线,储罐和高压泵之间设有回流管线,回流管线和高压泵之间设有截止阀,还包括集气装置,集气装置包括集气腔和集气腔出口的调压装置,高压泵设有排气阀,集气腔进口连接排气阀,调压装置出口连接储罐。本发明对回流CO-(2)进行调压处理,有利于储罐压力的稳定性。(The invention relates to the field of oil field development, and discloses injection equipment for carbon dioxide flooding, which comprises a storage tank, a canned pump, a high-pressure pump and an injection head which are sequentially arranged, wherein an injection pipeline is arranged between the high-pressure pump and the injection head, a backflow pipeline is arranged between the storage tank and the high-pressure pump, a stop valve is arranged between the backflow pipeline and the high-pressure pump, the injection equipment also comprises a gas collection device, the gas collection device comprises a gas collection cavity and a pressure regulating device of an outlet of the gas collection cavity, the high-pressure pump is provided with an exhaust valve, an inlet of the gas collection cavity is connected with the exhaust valve, and an outlet of the pressure regulating device is connected with the storage tank. Invention counter-current CO 2 The pressure regulation treatment is carried out, which is beneficial to the stability of the pressure of the storage tank.)

1. The utility model provides an injection equipment that carbon dioxide displacement of reservoir oil was used, is including storage tank, canned pump, high-pressure pump and the injection head that sets gradually, be provided with injection line between high-pressure pump and the injection head, the storage tank with be equipped with backflow line between the high-pressure pump, backflow line with be equipped with the stop valve between the high-pressure pump, its characterized in that still includes the gas collection device, the gas collection device includes the gas collection chamber and is located the pressure regulating device of gas collection chamber export, the high-pressure pump is equipped with discharge valve, gas collection chamber access connection discharge valve, the pressure regulating device exit linkage the storage tank.

2. The injection apparatus of claim 1, wherein the pressure regulating device comprises a pressure relief valve.

3. The injection apparatus of claim 2, wherein the pressure reducing valve is connected to the return line and a first check valve is disposed between the pressure reducing valve and the return line.

4. The injection equipment for carbon dioxide flooding of claim 1, wherein the gas collection chamber comprises a first gas collection chamber and a second gas collection chamber which are communicated, the first gas collection chamber is connected with the exhaust valve, and the volume of the second gas collection chamber is larger than that of the first gas collection chamber.

5. The injection equipment for carbon dioxide flooding of claim 4, wherein the gas collecting device further comprises a gas collecting tank, the inside of the gas collecting tank is partitioned to form the first gas collecting cavity and the second gas collecting cavity, and a second one-way valve is arranged between the gas collecting tank and the exhaust valve.

6. The injection equipment for carbon dioxide flooding according to claim 1, characterized by further comprising a pre-cooling device, wherein the pre-cooling device is disposed in the gas collection chamber;

or the inlet of the precooling device is connected with the exhaust valve, and the outlet of the precooling device is connected with the inlet of the gas collecting cavity;

or the inlet of the precooling device is connected with the outlet of the gas collecting device, and the outlet of the precooling device is connected with the backflow pipeline.

7. The injection apparatus for carbon dioxide flooding of claim 1, further comprising a heating device disposed between said high pressure pump and said injector head, said heating device comprising a heater and a heat exchanger.

8. The injection equipment for carbon dioxide flooding of claim 1, further comprising a variable frequency regulation device, wherein the variable frequency regulation device comprises a pressure sensor, a pressure transmitter and a frequency converter, the pressure sensor is respectively arranged at an injection wellhead, the pressure transmitter is arranged at the injection pipeline, the frequency converter is arranged at the high-pressure pump, and the pressure transmitter is connected with the frequency converter.

9. The injection apparatus for carbon dioxide flooding of claim 8, comprising a plurality of said injection heads corresponding to different injection wells, said high pressure pump being connected to each of said injection heads by a plurality of said injection lines connected in parallel.

10. The injection apparatus for carbon dioxide flooding of claim 9, wherein the variable frequency regulating device further comprises pressure regulating valves respectively disposed at the injection lines.

Technical Field

The invention relates to the technical field of oilfield development, in particular to injection equipment for carbon dioxide flooding.

Background

In the field of crude oil development, the carbon dioxide oil displacement technology is utilized, the crude oil recovery rate can be obviously improved for low-permeability oil reservoirs, and the sequestration technology can realize the resource utilization of greenhouse gases and is beneficial to environmental protection.

CO₂The oil displacement ground pressure injection process generally adopts CO₂Liquid phase CO stored in storage tank₂After being pressurized by the shielding pump, the gas is pressurized by the high-pressure pump to reach the injection pressure and then is delivered to the wellhead of the gas injection well. In the operation process of the high-pressure pump, liquid carbon dioxide entering the pump cavity is continuously vaporized and needs to be continuously exhausted, so that the pump efficiency is possibly low, the injection cannot be completed, the loss of the carbon dioxide is large, the energy consumption is caused, and the air is polluted.

To discharge CO₂Can be reused, in the prior art, the gas-phase CO is made to be reused by arranging a pipeline₂And refluxing to the storage tank. Due to gaseous phase CO discharged from the high-pressure pump₂Pressure is far higher than the pressure of storage tank, and under the pipeline pressure condition of not having the control, the mode that the lug connection storage tank carries out the backward flow leads to storage tank pressure constantly to increase, causes pressure unstable, and then influences subsequent confession liquid work. If the pressure of the storage tank is too large and cannot be borne, the safety in the use process cannot be guaranteed.

Disclosure of Invention

To address one or more of the problems of the prior art, or to at least provide a useful alternative, the present invention provides an injection apparatus for carbon dioxide flooding that operates on back-flowed CO₂The pressure regulation treatment is carried out, which is beneficial to the stability of the pressure of the storage tank.

The invention provides injection equipment for carbon dioxide flooding, which comprises a storage tank, a canned pump, a high-pressure pump and an injection head which are sequentially arranged, wherein an injection pipeline is arranged between the high-pressure pump and the injection head, a backflow pipeline is arranged between the storage tank and the high-pressure pump, a stop valve is arranged between the backflow pipeline and the high-pressure pump, the injection equipment also comprises a gas collection device, the gas collection device comprises a gas collection cavity and a pressure regulating device of an outlet of the gas collection cavity, the high-pressure pump is provided with an exhaust valve, an inlet of the gas collection cavity is connected with the exhaust valve, and an outlet of the pressure regulating device is connected with the storage tank.

In a preferred implementation of the injection device for carbon dioxide flooding, the pressure regulating means comprises a pressure reducing valve.

In a preferred implementation mode of the injection equipment for carbon dioxide flooding, the pressure reducing valve is connected with a return pipeline, and a first one-way valve is arranged between the pressure reducing valve and the return pipeline.

In a preferred implementation mode of the injection equipment for carbon dioxide flooding, the gas collection cavity comprises a first gas collection cavity and a second gas collection cavity which are communicated, the first gas collection cavity is connected with an exhaust valve, and the volume of the second gas collection cavity is larger than that of the first gas collection cavity.

In a preferred implementation mode of injection equipment for carbon dioxide flooding, the gas collection device further comprises a gas collection tank, a first gas collection cavity and a second gas collection cavity are formed in the gas collection tank in a separated mode, and a second one-way valve is arranged between the gas collection tank and the exhaust valve.

In a preferred implementation mode of the injection equipment for carbon dioxide flooding, the injection equipment also comprises a precooling device, wherein the precooling device is provided with a gas collection cavity;

or the inlet of the precooling device is connected with the exhaust valve, and the outlet of the precooling device is connected with the inlet of the gas collecting cavity;

or the inlet of the precooling device is connected with the outlet of the gas collecting device, and the outlet of the precooling device is connected with the return pipeline.

In a preferred implementation manner of the injection equipment for carbon dioxide flooding, the injection equipment further comprises a heating device, wherein the heating device is arranged between the high-pressure pump and the injection head, and comprises a heater and a heat exchanger.

In an implementation mode of optimization of injection equipment for carbon dioxide flooding, the injection equipment further comprises a variable frequency adjusting device, wherein the variable frequency adjusting device comprises a pressure sensor, a pressure transmitter and a frequency converter, the pressure sensor is arranged on an injection wellhead, the pressure transmitter is arranged on an injection pipeline, the frequency converter is arranged on a high-pressure pump, and the pressure transmitter is connected with the frequency converter.

In a preferred implementation mode of the injection equipment for carbon dioxide flooding, the injection equipment comprises a plurality of injection heads corresponding to different injection wells, and the high-pressure pump is respectively connected with the injection heads through a plurality of injection pipelines connected in parallel.

In a preferred implementation manner of the injection equipment for carbon dioxide flooding, the variable frequency adjustment device further comprises pressure adjustment valves respectively arranged on the injection pipelines.

The invention has the beneficial effects that:

1. the invention adopts a hydraulic feeding injection process, the storage tank provides a carbon dioxide source, the shield pump boosts the liquid carbon dioxide before entering the high-pressure pump, the resistance loss of a liquid inlet valve of the high-pressure pump is overcome, the carbon dioxide entering a pump cavity is ensured to be in a liquid phase state above supersaturated vapor pressure, and the defect of insufficient liquid supply at an inlet when the high-pressure pump is self-priming is overcome. Through setting up the backflow pipeline, carry out the circulation precooling cooling to the pump head of high-pressure pump, make it reach the temperature of technological requirement. For CO discharged from high pressure pump₂By arranging the gas collecting device, on one hand, the gas collecting cavity discharges CO in gas phase₂The pre-collection is carried out, because the cavity of the gas collection cavity is larger than the pump cavity of the high-pressure pump, the volume of CO2 is larger and the pressure is smaller after the CO2 enters the large cavity from the small cavity, and the primary pressure regulation treatment can be carried out; a pressure regulating device is further arranged, so that high-pressure CO is subjected to backflow₂Two-stage pressure regulation treatment to reduce CO flowing back to the storage tank₂And the pressure intensity ensures the stability of the pressure intensity in the storage tank. Meanwhile, through a multi-stage pressure reduction treatment mode with a gas collection cavity and a pressure regulating device, sudden pressure drop and CO are avoided₂The loss of pressure cured to dry ice plugged the line.

2. The pressure regulating device comprises a pressure reducing valve, and the pressure behind the pressure reducing valve can be kept within a certain range, so that CO in the gas collection cavity can be kept₂The pressure is reduced and stabilized to a desired pressure, and then the mixture is returned to the storage tank through a line. CO with pressure reducing valve capable of ensuring backflow₂Stability of pressure, further reduction of reflux CO₂Influence on the pressure stability of the storage tank. The existing pre-cooling return pipeline is used for conveying CO2, so that the pipeline arrangement is simplified, and the space and the cost are saved.

3. The gas collecting cavity comprises a first gas collecting cavity and a second gas collecting cavity which have different volumes, multi-stage automatic pressure reduction is carried out, and CO discharged by an exhaust valve₂The pressure is reduced by stages through the first gas collecting cavity and the second gas collecting cavity, thereby avoiding the over-quick pressure reduction and CO₂Becoming a case of dry ice.

4. The gas collecting device also comprises a precooling device, and CO is stored in the storage tank₂As liquid CO₂Precooling apparatus discharging CO₂The gas is cooled to a liquid state and flows back to the storage tank in a liquid phase, which is beneficial to ensuring CO in the storage tank₂And (4) phase stability.

5. The invention also comprises a variable frequency adjusting device which is used for adjusting the pressure and the flow of the carbon dioxide injection pipeline and injecting CO in the carbon dioxide oil displacement process₂The time is longer, and the injection volume change is great, through the pressure that obtains injection well head and injection line, adopts frequency conversion control to the high-pressure pump, adjusts the discharge capacity, improves the efficiency of pouring into. And the adaptability of the high-pressure pump for injection allocation can be enhanced, so that the high-pressure pump has wider adaptability to an injection system.

6. The invention adopts a single-pump multi-well mode, and CO is injected into a plurality of injection wells by arranging injection pipelines connected in parallel₂And the injection pipelines are not affected mutually. Through setting up pressure regulating valve, to the difference of each injection well head pressure, adjust the pressure of injection line, satisfy the required injection flow and the pressure of different well heads. To the condition that the injection well head is close, through the injection of a set of equipment alright realization a plurality of well heads, the facility is concentrated, and the management of being convenient for can realize the scale and inject into, and the partial pressure is injected into, saves the cost.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of an injection apparatus for carbon dioxide flooding in accordance with an embodiment of the present disclosure;

fig. 2 is a first schematic structural diagram of a precooling apparatus and a gas collecting apparatus according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a second pre-cooling device and a gas collecting device in an embodiment of the present invention.

Description of reference numerals:

1. a storage tank; 11. a safety valve;

2. a canned pump;

3. a high pressure pump; 31. an exhaust valve;

4. a gas collection device; 41. a gas collection tank; 42. a gas collection cavity; 421. a first gas collection chamber; 422. a second gas collection chamber; 43. a pressure reducing valve; 44. a first check valve; 45. a second one-way valve;

5. a pre-cooling device; 51. a refrigerator; 52. a refrigeration pipe;

6. an injection line;

7. a return line; 71. a stop valve;

8. a heating device;

9. a variable frequency adjustment device; 91. a frequency converter; 92. a pressure transmitter; 93. a pressure sensor; 94. a pressure regulating valve;

10. a flow divider.

Detailed Description

In order to more clearly explain the overall concept of the present invention, the following detailed description is given by way of example in conjunction with the accompanying drawings.

It should be noted that in the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and thus the scope of the present invention is not limited by the specific embodiments disclosed below.

In addition, in the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate orientations and positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; either directly or indirectly through intervening media, either internally or in any other relationship. However, the direct connection means that the two bodies are not connected through a transition structure, but connected through a connection structure to form a whole. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The specific scheme is as follows:

an embodiment of the invention provides injection equipment for carbon dioxide flooding, which comprises a storage tank 1, a canned pump 2, a high-pressure pump 3 and an injection head which are sequentially arranged, wherein an injection pipeline 6 is arranged between the high-pressure pump 3 and the injection head, as shown in fig. 1. The interlayer of the inner container and the outer container of the storage tank 1 is filled with heat insulation materials for heat insulation and preservation, for example, the interlayer is filled with pearly-lustre sand and vacuumized to form a vacuum powder heat insulation layer for heat preservation, and the heat preservation effect is good. The upper part of the storage tank 1 is provided with the pressure gauge, the differential pressure type liquid level meter, the liquid level comparison meter and the safety valve 11, so that the storage capacity and the pressure change of the container can be mastered at any time, the operation during filling and discharging is convenient, and the safe operation of the storage tank 1 is ensured. The liquid inlet of the storage tank 1 can be connected with a tank car for liquid supplement. The shield pump 2 is a reverse circulation shield pump, and has low noise, no leakage and stable operation. The high-pressure pump 3 adopts a three-plunger 3RC horizontal three-plunger reciprocating type carbon dioxide injection pump, and the pump has the advantages of compact structure, small volume, stable and reliable operation and high efficiency.

The injection equipment adopts a hydraulic injection feeding process, the storage tank 1 provides a carbon dioxide source, the temperature range in the storage tank 1 is minus 20 ℃ to minus 30 ℃, and the pressure range is 1.5 MPa to 2.5 MPa. The shielding pump 2 is used for pressurizing liquid carbon dioxide before entering the high-pressure pump 3, the pressure at the outlet of the shielding pump 2 is about 2.8MPa, resistance loss of a liquid inlet valve of the high-pressure pump 3 is favorably overcome, the carbon dioxide entering a pump cavity is ensured to be in a liquid phase state above supersaturated vapor pressure, and the defect of insufficient liquid supply at the inlet when the high-pressure pump 3 is self-priming is overcome. High pressure pump 3 pumping CO₂And pressurizing to 25MPa, conveying to an injection head, and injecting into the well.

A return line 7 is provided between the storage tank 1 and the high-pressure pump 3, and a stop valve 71 is provided between the return line 7 and the high-pressure pump 3. Through setting up backflow pipeline 7, carry out the circulation precooling cooling to high-pressure pump 3 pump head and system's pipeline, make it reach the temperature and the pressure condition of technological requirement. Carrying out CO₂Before injection, the stop valve 71 is opened, the outlet of the high-pressure pump 3 is closed, the high-pressure pump 3 is started, and liquid CO in the high-pressure pump 3₂Is returned to the tank 1 via a return line 7. Maintaining precooling reflux circulation for a period of time to enable the pump head of the high-pressure pump 3 to cool and approach CO in the storage tank 1₂The temperature of (2). Thereafter, the shutoff valve 71 is closed, and the outlet of the high-pressure pump 3 is opened for injection. In one embodiment, the shield pump 2 has a flow greater than the injection pump 3, which can avoid liquid CO₂After vaporization, the absorption of the shield pump 2 and the high-pressure pump 3 is influenced, and liquid CO is maintained₂Is always in an oversaturated state. During the filling process, the shut-off valve 71 is still open, muchThe remaining liquid is used to cool the shield pump 2 and the injection pump 3, and is returned to the storage tank 1 through the return line 7.

In one embodiment, as shown in fig. 1, the injection device further comprises a gas collection device 4, the gas collection device 4 comprises a gas collection chamber 42 and a pressure regulating device at the outlet of the gas collection chamber 42, the high pressure pump 3 is provided with a vent valve 31 for vaporized CO₂The gas is easy to gather at the top of the high-pressure pump 3, so the exhaust valve 31 is arranged at the top of the high-pressure pump 3, the inlet of the gas collection cavity 42 is connected with the exhaust valve 31, and the outlet of the pressure regulating device is connected with the storage tank 1.

For CO discharged from the high pressure pump 3₂By providing a gas collection device 4 in which the gas collection chamber 42 is aligned with the discharged gas phase CO₂The pre-collection is performed because the volume of the gas collection chamber 42 is larger than that of the pump chamber of the high pressure pump 3. CO2₂After entering the large chamber from the small chamber, the volume is increased and the pressure intensity is reduced, thereby treating CO₂And performing primary pressure regulating treatment. A pressure regulating device is further arranged, so that high-pressure CO is subjected to backflow₂Secondary pressure regulating treatment, CO after pressure regulating treatment₂The pressure is stabilized to the required pressure value range, and the pressure stability in the storage tank 1 is ensured. Meanwhile, according to the Bernoulli principle of hydrodynamics, sudden pressure drop can cause CO₂And (4) losing pressure and locally forming solid dry ice. Through the multistage pressure reduction treatment mode with the gas collection cavity and the pressure regulating device, CO can be avoided₂The condition of pipeline blockage due to pressure loss and condensation is caused by dry ice.

In one embodiment, the gas collecting device comprises a plurality of gas collecting cavities connected in parallel, and each gas collecting cavity is connected with the pressure regulating device to form a multi-stage pressure reduction structure. Or, in one embodiment, the gas injection device comprises a plurality of gas collecting devices connected in series, wherein a gas collecting cavity of one gas collecting device is connected with the exhaust valve, and each gas collecting device is subjected to pressure reduction treatment and combined to form a multi-stage pressure reduction structure.

In one embodiment, as shown in fig. 1, the pressure regulating device includes a pressure reducing valve 43, and an inlet of the pressure reducing valve 43 is connected to an outlet of the gas collecting chamber 42. The post-valve pressure of the pressure reducing valve 43 can be maintained within a certain range, thereby keeping CO in the gas collecting chamber 42₂Depressurized and stabilized to the desired pressure and returned via lineInto the tank 1, a pressure relief valve 43 can ensure the return CO₂Stability of pressure, further reduction of reflux CO₂Influence on the pressure stability of the tank 1.

In one embodiment, as shown in fig. 1, the pressure reducing valve 43 is connected to the return line 7, and a first check valve 44 is provided between the pressure reducing valve and the return line 7, and the direction from the gas collecting device 4 to the return line 7 in the first check valve 44 is a forward direction. The first one-way valve 44 can avoid CO in the process of cyclic precooling₂Flows to the gas collecting device 4. CO transport by means of the existing pre-cooling return line 7₂The pipeline arrangement is simplified, and the space and the cost are saved. It will be understood by those skilled in the art that a separate line may be provided for connection between the pressure reducing valve 43 and the tank 1, in which case no CO is present₂Back flow to the gas collection means and therefore the first one-way valve 44 can be omitted.

As shown in FIG. 1, CO₂In the pressure injection process, the exhaust backflow process is as follows: after the high-pressure pump 3 enters the injection state, the shutoff valve 71 is closed. The pressure reducing valve 43 is opened, and the exhaust valve 31 is intermittently opened to exhaust gas, gaseous CO₂After being decompressed by the gas collecting cavity 42 and the pressure reducing valve 43, the gas enters the return pipeline 7 and is transmitted to the storage tank 1.

As shown in fig. 1-3, in one embodiment, the gas collecting chamber 42 includes a first gas collecting chamber 421 and a second gas collecting chamber 422 which are communicated with each other, the first gas collecting chamber 421 is connected to the exhaust valve 31, and the volume of the second gas collecting chamber 422 is larger than that of the first gas collecting chamber 421, so that CO in the second gas collecting chamber 422₂The pressure is less than the first plenum 421. The gas collecting chamber 42 comprises a first gas collecting chamber 421 and a second gas collecting chamber 422 with different volumes, and performs multi-stage automatic pressure reduction on CO discharged by the exhaust valve₂The pressure is reduced by stages through the first gas collecting cavity 421 and the second gas collecting cavity 422, thereby avoiding the over-quick pressure reduction and CO₂Becoming a case of dry ice.

As shown in fig. 1, in one embodiment, the gas collecting device 4 further includes a gas collecting tank 41, and the gas collecting tank 41 is provided with a heat insulating layer for heat insulation treatment, like the storage tank 1. The interior of the gas collecting tank 41 is partitioned into a first gas collecting cavity 421 and a second gas collecting cavity 422, and the first gas collecting cavity 421 is communicated with the second gas collecting cavity 422.A second one-way valve 45 is arranged between the gas collection tank 41 and the exhaust valve 31. The direction from the high-pressure pump 3 to the gas collecting device 4 in the second check valve 45 is a forward conducting direction. After the high-pressure pump 3 stops working, the high-pressure pump 3 needs to be emptied, and CO in the high-pressure pump is discharged on the premise of connecting the return pipeline 7₂Can flow back to the storage tank 1 for the next startup. In the emptying process, the pressure in the high-pressure pump 3 is gradually reduced, and the second one-way valve 45 is arranged, so that CO in the gas collection cavity 42 can be prevented from being generated when the pressure in the gas collection cavity 42 is greater than that of the high-pressure pump 3₂Reverse flow to the high pressure pump 3, thereby facilitating CO injection into the high pressure pump₂All are discharged.

As shown in fig. 1-3, in an embodiment the injection device further comprises a pre-cooling means 5, due to the storage of CO in the tank 1₂As liquid CO₂The pre-cooling device 5 is capable of cooling the discharged CO at a predetermined pressure₂The gas is cooled to a liquid state and flows back to the storage tank 1 in a liquid phase, which is beneficial to ensuring CO in the storage tank 1₂And (4) phase stability. The arrangement position of the pre-cooling device 5 can be various, and the pre-cooling device is arranged at the front end of the gas collecting device 4 or at the rear end of the gas collecting device 4 or in the gas collecting device 4.

In one embodiment, as shown in fig. 1, the pre-cooling device 5 is disposed in the gas collecting chamber 42, and the pre-cooling device 5 includes a refrigerator 51 disposed above the gas collecting chamber 42 and a refrigerating pipe 52 disposed around the gas collecting chamber 42, so that pre-cooling is simultaneously achieved during the pressure reducing process. The pre-cooling device 5 is integrated in the gas collecting cavity 42, as shown in fig. 1, the pre-cooling device 5 is arranged in the gas collecting tank 41, a refrigerator 51 is placed on the upper portion of the gas collecting tank 41, and the refrigerator 51 is connected with a refrigerating pipe 52 surrounding the gas collecting cavity 42, so that the uniformity of the pre-cooling effect of the gas collecting cavity 42 is ensured. Precooled and pressure-regulated CO₂After the secondary pressure regulation treatment by the pressure reducing valve 43, the CO in the return pipeline 7 can be ensured₂Pressure stability of (2). In addition, the mode of integrating the setting can simplify the structure, saves space.

As shown in FIG. 2, in one embodiment, the inlet of the pre-cooling device 5 is connected with the exhaust valve 31, and the outlet of the pre-cooling device 5 is connected with the inlet of the gas collecting cavity 42, which can also ensure that CO in the return line is ensured₂Pressure stability of (2).

As shown in fig. 3, in one embodiment, the pre-cooling device 5 is disposed at the rear end of the gas collecting device 4, an inlet of the pre-cooling device 5 is connected to an outlet of the pressure reducing valve 43, and an outlet of the pre-cooling device 5 is connected to the return line 7. CO after pressure reduction₂Precooling, liquefying and refluxing are carried out to avoid CO₂Secondary vaporization occurs during the depressurization.

As shown in fig. 1, in one embodiment, the injection device further comprises a heating device 8, the heating device 8 is arranged between the high-pressure pump 3 and the injection head, and the heating device 8 comprises a heater and a heat exchanger, wherein the heater is selected from an electric heater or a fuel heater. Heating CO₂The temperature is in the range of 0 to-10 ℃, and the liquid state of the carbon dioxide is always kept. Will CO in supercooled state₂When the injection is carried out after heating, the casing of the injection well can be protected from being frozen and the safety of the operation of workers can be improved.

As shown in fig. 1, in one embodiment, the injection equipment further comprises a variable frequency regulating device 9, the variable frequency regulating device 9 comprises a pressure sensor 93 respectively arranged at the injection wellhead, a pressure transmitter 92 arranged at the injection pipeline 6 and a frequency converter 91 arranged at the high-pressure pump 3, and the pressure transmitter 92 is connected with the frequency converter 91. The variable frequency adjusting device 9 can adjust the pressure and flow of the carbon dioxide injection pipeline 6, and CO is injected in the carbon dioxide flooding process₂The time is longer, and the injection volume change is great, through the pressure that obtains injection well head and injection line 6, adopts frequency conversion control to high-pressure pump 3, adjusts the discharge capacity, improves the efficiency of pouring into. And the adaptability of the high-pressure pump 3 to injection can be enhanced, so that the adaptability of the high-pressure pump 3 to an injection system is wider.

In one embodiment, comprising a plurality of injection heads corresponding to different injection wells, the high pressure pump 3 is connected to each injection head by a plurality of injection lines 6 in parallel. In fig. 1 there are shown 2 injection lines 6 communicating with different injection heads, connected to a high pressure pump 3 by means of a flow divider 10.

In one embodiment, the variable frequency regulation device 9 further comprises a pressure regulating valve 94 respectively arranged at each injection line 6.

The injection apparatus implements a single pump multi-well mode,CO injection into a plurality of injection wells by providing parallel injection lines 6₂The injection lines 6 do not interfere with each other. By providing the pressure regulating valve 94, the pressure of the injection line 6 is regulated for the difference in pressure at each injection well head, and the injection flow and pressure required at different well heads are met. To the condition that the injection well head is close, through the injection of a set of equipment alright realization a plurality of well heads, the facility is concentrated, and the management of being convenient for can realize the scale and pour into, partial pressure injection.

The technical solutions protected by the present invention are not limited to the above embodiments, and it should be noted that the combination of the technical solution of any one embodiment and the technical solution of one or more other embodiments is within the protection scope of the present invention. Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.