Wellhead dosing device

Abstract

The utility model belongs to the technical field of oil and gas exploitation, and particularly relates to a wellhead dosing device. The well mouth chemical feeding device feeds chemicals into a well through a casing gate of a well mouth and comprises a chemical storage tank used for containing chemicals, and the chemical storage tank is connected with the casing gate; the chemical feeding end of the chemical feeding pump is connected with the chemical storage tank, and the chemical discharging end of the chemical feeding pump is connected with the sleeve gate; the air compressor is used for providing power for the dosing pump, and a high-pressure storage tank is arranged between the dosing pump and the air compressor.

Description

Technical Field

[0001] The utility model belongs to the technical field of oil and gas exploitation, and in particular relates to a wellhead dosing device. Background Art

[0002] During the heavy oil production process in the oil field, in the later stage of the injection and production cycle, as the formation temperature decreases, the crude oil viscosity increases, and the lifting equipment is unable to lift the crude oil to the ground. At the same time, the formation still has a certain amount of energy, which can move the crude oil in the formation to the wellbore. At this time, we need to reduce the viscosity of the crude oil to reach the appropriate viscosity range for the lifting equipment to ensure normal operation of the equipment.

[0003] At present, the viscosity of crude oil is mainly reduced through the following methods: steam heating, in which a small amount of steam is injected into the oil layer around the wellbore through the wellhead to reduce the viscosity of the oil layer and the crude oil in the wellbore; viscosity reducer, in which a viscosity reducer diluted by about 5% is added into the wellbore through the annulus of the oil casing to reduce the viscosity of the crude oil in the wellbore; thin oil viscosity reduction, in which thin oil is added through the annulus of the oil casing, and the thin oil and heavy oil are mixed in the wellbore to reduce the viscosity of the crude oil; electric heating, in which a cable is added to the hollow sucker rod. When the cable is energized, heat is generated, and the viscosity of the crude oil is reduced by increasing the temperature during the lifting process.

[0004] At present, the more common practice is to add viscosity reducers, and the viscosity reducer adding equipment used mainly includes: metering pump dosing, which has accurate dosing amount and is more suitable for oil wells with higher back pressure. It requires a dosing system and has a large investment; wellhead gravity dosing, in which a set of higher-positioned tanks are installed at the wellhead, and the tanks rely on the height difference with the wellhead to flow into the wellbore. This dosing method requires low wellhead pressure and low dynamic liquid level; relying on the power of the pumping unit to add the viscosity reducer into the wellbore, generally the up and down swing of the walking beam pumping unit is used to provide power to the dosing device. This device makes better use of external power and is widely used in oil fields. The disadvantage is that the dosing power device is located at a higher position, and it is more difficult to inhale the agent.

[0005] Therefore, it is urgent to develop a wellhead dosing device. Utility Model Content

[0006] In response to the above-mentioned technical problems, the present invention aims to provide a wellhead dosing device, which can solve at least one of the above-mentioned technical problems.

[0007] According to the utility model, a wellhead dosing device is provided, which adds drugs into the well through the casing gate at the wellhead, comprising:

[0008] A medicine storage tank for containing medicine, the medicine storage tank being connected to the casing gate;

[0009] A dosing pump, wherein the drug inlet end of the dosing pump is connected to the drug storage tank, and the drug outlet end of the dosing pump is connected to the casing gate;

[0010] An air compressor provides power for the dosing pump, and a high-pressure storage tank is provided between the dosing pump and the air compressor.

[0011] In a specific embodiment, the dosing pump comprises:

[0012] Cylinder body;

[0013] a first piston and a second piston movably arranged in the cylinder body along the axial direction, wherein the first piston and the second piston are fixed to each other;

[0014] The first power end and the second power end are respectively arranged at the axial ends of the cylinder body, and the first power end and the second power end are connected to the high-pressure storage tank and the discharge pipe through a reversing valve.

[0015] The drug inlet end and the drug outlet end are both arranged on the side of the cylinder body and located between the first piston and the second piston. A first one-way valve that only allows fluid to flow into the cylinder body is provided at the drug inlet end, and a second one-way valve that only allows fluid to flow out of the cylinder body is provided at the drug outlet end.

[0016] In a specific embodiment, a partition is provided in the cylinder body to separate the first piston and the second piston, the drug inlet end includes a first drug inlet pipe and a second drug inlet pipe respectively provided on both sides of the axial direction of the partition, and the drug outlet end includes a first drug outlet pipe and a second drug outlet pipe respectively provided on both sides of the axial direction of the partition.

[0017] In a specific embodiment, the first piston and the second piston are fixedly connected via a tie rod, and the tie rod movably seals through the partition.

[0018] In a specific embodiment, the two first one-way valves are respectively provided on the first drug inlet pipe and the second drug inlet pipe, and the two second one-way valves are respectively provided on the first drug outlet pipe and the second drug outlet pipe.

[0019] In a specific embodiment, the reversing valve includes:

[0020] a valve body, on which is provided a first port connected to the first power end or the second power end, a second port connected to the high-pressure storage tank, and a third port connected to the discharge pipe;

[0021] A valve core rotatably disposed within the valve body;

[0022] In a first state, the valve core connects the first port and the second port;

[0023] In the second state, the valve element connects the first port and the third port.

[0024] In a specific embodiment, a sensor capable of detecting positions of the first piston and the second piston is provided in the cylinder body, and the reversing valve can perform an action in response to an electrical signal sent by the sensor.

[0025] In a specific embodiment, the first power end and the second power end both extend into the cylinder body, and the two sensors are respectively arranged at the ends of the first power end and the second power end both extending into the cylinder body.

[0026] In a specific embodiment, the medicine storage tank is connected to the casing gate via a pressure balancing pipe, and the position where the pressure balancing pipe is connected to the medicine storage tank is higher than the liquid level in the medicine storage tank.

[0027] In a specific embodiment, the drug outlet end of the dosing pump is connected to the sleeve gate through a concentric tube, and the concentric tube includes:

[0028] an inner tube, wherein both ends of the inner tube are respectively connected to the medicine outlet end and the sleeve gate;

[0029] An outer tube is coaxially arranged outside the inner tube, one end of the outer tube is fixedly connected to the inner tube, and the other end is connected to the casing gate, and the end of the pressure balance tube away from the medicine storage tank is connected to the outer tube.

[0030] Compared with the prior art, the advantages of this application are as follows.

[0031] The utility model uses high-pressure gas as a power source, controls the operation of the reversing valve through the signal of the sensor, and the medicine enters the oil casing annulus through the action of the dosing pump. The pressure difference between the oil casing pressure and the medicine tank is balanced through the pressure balance pipe, so that the medicine can be added to the oil casing annulus with relatively small power. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be described below with reference to the accompanying drawings.

[0033] Figure 1 A schematic diagram showing an embodiment of a wellhead dosing device proposed in the present utility model is shown;

[0034] Figure 2 and Figure 3 A schematic diagram showing an embodiment of a dosing pump according to the present utility model is shown;

[0035] Figure 4 and Figure 5 A schematic diagram showing an embodiment of a reversing valve proposed in the present utility model is shown;

[0036] Figure 6 A schematic diagram showing the connection of the concentric tubes to the pressure equalization tube is shown.

[0037] The reference numerals in the figures are as follows:

[0038] 1. Drug storage tank; 11. Drug adding port;

[0039] 2. Dosing pump; 21. Drug inlet; 211. First drug inlet pipe; 212. Second drug inlet pipe; 22. Drug outlet; 221. First drug outlet pipe; 222. Second drug outlet pipe; 23. First one-way valve; 24. Second one-way valve; 25. First power end; 26. Second power end; 27. Reversing valve; 271. Valve body; 272. Valve core; 273. First port; 274. Second port; 275. Third port; 201. Cylinder; 202. First piston; 203. Second piston; 204. Partition; 205. Tie rod;

[0040] 3. Air compressor; 31. High-pressure storage tank; 32. Discharge pipe;

[0041] 4. Concentric tube; 41. Inner tube; 42. Outer tube; 43. Pressure balance tube; 44. One-way float valve;

[0042] 5. Sensor;

[0043] 10. Casing gate;

[0044] 100. Wellhead dosing device.

[0045] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0046] The present invention will be described below with reference to the accompanying drawings.

[0047] It should be noted that the directional terms or qualifiers "upper", "lower", "left", "right" etc. used in this application are all directed to the referenced Figure 2 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific situation.

[0048] Figure 1 The structure of the wellhead dosing device 100 according to the present invention is shown. Figure 1 As shown, the casing gate 10 is arranged at the wellhead, and the casing annulus in the well can be connected through the casing gate 10. The wellhead dosing device 100 mainly includes a drug storage tank 1, a dosing pump 2 and an air compressor 3.

[0049] like Figure 1 and Figure 6As shown, the drug storage tank 1 is used to hold drugs, and a drug addition port 11 for loading drugs is provided at the top of the drug storage tank 1. When the drug addition port 11 is closed, the drug storage tank 1 becomes a high-pressure sealed tank, and the drug storage tank 1 is connected to the casing gate 10, so that the pressure in the drug storage tank 1 is equal to the pressure in the downhole oil and casing annulus, allowing the drugs in the drug storage tank 1 to enter the oil and casing annulus with less power.

[0050] The dosing pump 2 includes a drug inlet 21 and a drug outlet 22. The drug inlet 21 of the dosing pump 2 is connected to the drug storage tank 1, and the drug outlet 22 of the dosing pump 2 is connected to the casing gate 10. After the dosing pump 2 is started, the drug in the drug storage tank 1 can be pumped into the dosing pump 2, and then the drug is pumped into the casing gate 10 and into the oil-casing annulus.

[0051] The air compressor 3 provides power for the dosing pump 2, and a high-pressure storage tank 31 is provided between the dosing pump 2 and the air compressor 3. In this embodiment, the air compressor 3 can be driven by electricity generated by solar energy or wind energy. Solar energy and wind energy generation are unstable. When solar power generation is at its peak, the air compressor 3 starts to work during this period, and excess high-pressure gas enters the high-pressure storage tank 31. When the pressure of the high-pressure storage tank 31 reaches the upper limit, the air compressor 3 stops working, and the dosing pump 2 relies on the energy of the high-pressure storage tank 31 for power. When the pressure of the high-pressure storage tank 31 drops to 80% of the upper limit, the air compressor 3 starts again. When solar power generation is at its low peak, the dosing pump 2 uses the power provided by the high-pressure storage tank 31 to complete the dosing work.

[0052] In a specific embodiment, Figure 2 and Figure 3 As shown, the dosing pump 2 includes a cylinder 201 , which is configured to be substantially in the shape of a long cylinder.

[0053] A first piston 202 and a second piston 203 are axially movable in the cylinder 201 , and the first piston 202 and the second piston 203 are fixed to each other. In other words, the first piston 202 and the second piston 203 can move synchronously along the axial direction of the cylinder 201 .

[0054] The drug inlet end 21 and the drug outlet end 22 are both arranged on the side of the cylinder body 201 and located between the first piston 202 and the second piston 203. A first one-way valve 23 that only allows fluid to flow into the cylinder body 201 is provided at the drug inlet end 21, and a second one-way valve 24 that only allows fluid to flow out of the cylinder body 201 is provided at the drug outlet end 22.

[0055] A partition 204 is provided in the cylinder body 201 to separate the first piston 202 and the second piston 203. In this embodiment, the partition 204 is fixedly provided in the middle of the cylinder body 201, dividing the cylinder body 201 into two mutually unconnected cavities on the left and right sides. The first piston 202 and the second piston 203 are respectively located in the left and right cavities of the cylinder body 201. A pull rod 205 is axially provided through the center of the partition 204, and the pull rod 205 and the partition 204 are in movable sealing cooperation. In other words, the pull rod 205 can move axially relative to the partition 204 while also ensuring the seal between the pull rod 205 and the partition 204. The first piston 202 and the second piston 203 are respectively fixedly provided at the left and right ends of the pull rod 205, thereby achieving synchronous movement of the first piston 202 and the second piston 203.

[0056] The drug inlet port 21 is located on the upper side of the cylinder 201 and includes a first drug inlet pipe 211 and a second drug inlet pipe 212, respectively, disposed on either side of the partition 204. The first drug inlet pipe 211 is connected to the cylinder 201 between the first piston 202 and the partition 204, while the second drug inlet pipe 212 is connected to the cylinder 201 between the second piston 203 and the partition 204. Two first one-way valves 23 are respectively disposed on the first drug inlet pipe 211 and the second drug inlet pipe 212.

[0057] The drug outlet 22 is located at the lower side of the cylinder 201 and includes a first drug outlet pipe 221 and a second drug outlet pipe 222, respectively, disposed axially on either side of the partition 204. The first drug outlet pipe 221 connects to the cylinder 201 between the first piston 202 and the partition 204, while the second drug outlet pipe 222 connects to the cylinder 201 between the second piston 203 and the partition 204. Two second one-way valves 24 are respectively disposed on the first drug outlet pipe 221 and the second drug outlet pipe 222.

[0058] In this setting, if Figure 2 As shown, when the first piston 202 and the second piston 203 move to the right, the medicine between the first piston 202 and the partition 204 is squeezed, and the medicine is discharged from the cylinder 201 through the first medicine outlet pipe 221 and flows toward the sleeve gate 10. At the same time, the space between the second piston 203 and the partition 204 increases, forming a negative pressure, causing the medicine in the medicine storage tank 1 to enter the cylinder 201 through the second medicine inlet pipe 212. Figure 3As shown, when the first piston 202 and the second piston 203 move leftward, the space between the first piston 202 and the partition 204 increases, creating negative pressure, forcing the medicine in the medicine storage tank 1 into the cylinder 201 through the first medicine inlet pipe 211. Simultaneously, the medicine between the second piston 203 and the partition 204 is squeezed, and the medicine is discharged from the cylinder 201 through the second medicine outlet pipe 222 and flows toward the sleeve gate 10. The first piston 202 and the second piston 203 move alternately left and right, continuously pumping the medicine in the medicine storage tank 1 into the sleeve gate 10.

[0059] According to the utility model, if Figure 2 As shown, a first power end 25 and a second power end 26 are respectively connected to the two axial ends of the cylinder body 201 , and the first power end 25 and the second power end 26 are both connected to the high-pressure storage tank 31 and the discharge pipe 32 through a reversing valve 27 .

[0060] like Figure 4 and Figure 5 As shown, the reversing valve 27 includes a valve body 271 and a valve core 272. The valve body 271 is provided with a first port 273 connected to the first power end 25 or the second power end 26, a second port 274 connected to the high pressure storage tank 31, and a third port 275 connected to the discharge pipe 32.

[0061] That is, the two reversing valves 27 are respectively arranged at the first power end 25 and the second power end 26. Figure 2 As shown, the first port 273 of the reversing valve 27 on the left side is connected to the first power end 25, the second port 274 is connected to the high-pressure storage tank 31, and the third port 275 is connected to the discharge pipe 32. The first port 273 of the reversing valve 27 on the right side is connected to the second power end 26, the second port 274 is connected to the high-pressure storage tank 31, and the third port 275 is connected to the discharge pipe 32.

[0062] The valve core 272 is rotatably disposed in the valve body 271. Figure 4 and Figure 5 As shown, in the first state, the valve core 272 connects the first port 273 and the second port 274, thereby allowing the high-pressure storage tank 31 to communicate with the first power end 25 or the second power end 26. In the second state, the valve core 272 connects the first port 273 and the third port 275, thereby allowing the first power end 25 or the second power end 26 to communicate with the exhaust pipe 32.

[0063] In this setting, if Figure 2As shown, when the first piston 202 and the second piston 203 need to move to the right, the reversing valve 27 provided on the first power end 25 is in the first state, that is, the high-pressure storage tank 31 is connected to the first power end 25, and the high-pressure gas in the high-pressure storage tank 31 can enter the cylinder 201 through the first power end 25, thereby pushing the first piston 202 to move to the right. The reversing valve 27 provided on the second power end 26 is in the second state, that is, the discharge pipe 32 is connected to the second power end 26. During the movement of the first piston 202 to the right, the second piston 203 is also driven to move to the right. The gas to the right of the second piston 203 is discharged from the cylinder 201 through the second power end 26 and finally discharged through the discharge pipe 32.

[0064] like Figure 3 As shown, when the first piston 202 and the second piston 203 need to move leftward, the reversing valve 27 provided on the second power end 26 is in the first state, i.e., the high-pressure storage tank 31 is connected to the second power end 26, and the high-pressure gas in the high-pressure storage tank 31 can enter the cylinder 201 through the second power end 26, thereby pushing the second piston 203 to move leftward. The reversing valve 27 provided on the first power end 25 is in the second state, i.e., the discharge pipe 32 is connected to the first power end 25. During the leftward movement of the second piston 203, the first piston 202 is also driven to move leftward. The gas on the left side of the first piston 202 is discharged from the cylinder 201 through the first power end 25 and finally discharged through the discharge pipe 32.

[0065] In a preferred embodiment, the end of the discharge pipe 32 is connected to the inlet of the air compressor 3 to increase the inlet pressure and further reduce the energy loss of the air compressor 3 .

[0066] In a preferred embodiment, a sensor capable of detecting the positions of the first piston 202 and the second piston 203 is provided in the cylinder body 201, and the reversing valve 27 can perform an action in response to the electrical signal sent by the sensor, thereby automatically switching between the first state and the second state.

[0067] Furthermore, the first power end 25 and the second power end 26 both extend into the cylinder 201, and two sensors are respectively disposed at the ends of the first power end 25 and the second power end 26 that extend into the cylinder 201. When the first piston 202 moves leftward and approaches the sensor on the first power end 25, the sensor emits a signal, and the reversing valves 27 on the first power end 25 and the second power end 26 respond to the signal. The reversing valve 27 on the first power end 25 switches to a first state, and the reversing valve 27 on the second power end 26 switches to a second state. At this point, the first piston 202 and the second piston 203 shift to the right. When the second piston 203 moves rightward and approaches the sensor on the second power end 26, the sensor emits a signal, and the reversing valves 27 on the first power end 25 and the second power end 26 respond to the signal. The reversing valve 27 on the first power end 25 switches to a second state, and the reversing valve 27 on the second power end 26 switches to a first state. At this point, the first piston 202 and the second piston 203 shift to the left.

[0068] According to the utility model, if Figure 1 and Figure 6 As shown, the medicine storage tank 1 is connected to the casing gate 10 via a pressure balancing pipe 43 , and the position where the pressure balancing pipe 43 is connected to the medicine storage tank 1 is higher than the liquid level in the medicine storage tank 1 .

[0069] In a preferred embodiment, the drug outlet end 22 of the dosing pump 2 is connected to the casing gate 10 through a concentric tube 4. The concentric tube 4 includes an inner tube 41 and an outer tube 42. The outer tube 42 is coaxially arranged on the outside of the inner tube 41. The two ends of the inner tube 41 are respectively connected to the drug outlet end 22 and the casing gate 10. The left end of the outer tube 42 is fixedly connected to the inner tube 41, thereby sealing the annulus between the outer tube 42 and the inner tube 41, and the right end is connected to the casing gate 10. The end of the pressure balance tube 43 away from the medicine storage tank 1 is connected to the side wall of the outer tube 42, thereby communicating with the annulus between the outer tube 42 and the inner tube 41, and then connected to the casing gate 10. Under this setting, the casing gate 10 only needs to be provided with an interface to connect with the outer tube 42.

[0070] like Figure 6 As shown, in a preferred embodiment, a one-way float valve 44 is provided within the pressure equalization tube 43. The one-way float valve 44 automatically closes under the buoyancy of the liquid, preventing liquid from entering the chemical storage tank 1 through the one-way float valve 44, while allowing gas to pass through. The one-way float valve 44 prevents downhole liquid from entering the chemical storage tank 1.

[0071] The casing pressure of heavy oil wells varies greatly. In order to maintain production, a lower casing pressure is generally used. However, due to changes in pressure parameters in the reservoir, the pressure at the wellhead is in an unstable state. A high-pressure drug storage tank 1 is used, which reduces the inlet and outlet pressure difference of the dosing pump 2 through the pressure balance pipe 43, thereby reducing the energy consumption of the dosing pump 2; when the wellhead is in a high-pressure state, the casing pressure is transmitted to the drug storage tank 1 through the pressure balance pipe 43, and the pressure of the drug storage tank 1 increases and is transmitted to the liquid surface, causing the inlet pressure of the dosing pump 2 to increase. The dosing pump 2 only needs to overcome its own resistance and the pipe loss along the way to add the drug to the well. When the wellhead is in a low-pressure state, a certain oil field well has a production of 11.5t / d, a wellhead viscosity of 5382mps, and a temperature of 42°. It is necessary to add a 5% concentration viscosity reducer at the wellhead on site to implement the wellhead viscosity reducer, and the dosing injection flow is controlled at 2m 3 / d. The wellhead oil pressure was 0.6 MPa, the casing pressure was 0.1 MPa, the well depth was 783 m, and the dynamic liquid level was 324 m. The fluid supply was sufficient, but due to high viscosity and low pump efficiency, wellbore viscosity reduction was required to ensure fluid supply. Using a wellhead dosing device 100 at a daily dosing rate of 1.8 m / d, the wellhead viscosity was reduced to 634 m / s, and production increased to 21 t / d. The dynamic liquid level was 281 m.

[0072] In one specific embodiment, when the casing pressure of the heavy oil well is high (1.2 MPa), the casing pressure is applied to the chemical storage tank 1 through the outer tube 42 of the concentric tube 4 and the pressure balance tube 43. This pressure is then transmitted to the inlet of the dosing pump 2, increasing the inlet pressure (1.0 MPa). This reduces the inlet and outlet pressure difference of the dosing pump 2 (0.2 MPa), thereby reducing the power loss during the piston movement. When the casing pressure is low (0.05 MPa below atmospheric pressure), the one-way float valve 44 closes, maintaining atmospheric pressure in the chemical storage tank 1. This pressure is then transmitted to the inlet of the dosing pump 2 (0.1 MPa), reducing the outlet pressure (0.1 MPa) of the dosing pump 2, similarly reducing power loss.

[0073] In a specific embodiment, the viscosity reducer was added to three wells at the same time. In a certain oil field, three wells, 9085, 9079 and 9061, were in the same formation. The viscosity of the crude oil at the wellhead was 3470 mps, the temperature was 38°, and the production without adding the drug was 2.3, 1.9 and 3.1 m3 respectively. 3 / d, with a water content of 20-47%. According to the design, the viscosity reducer was screened out, and the dosage was 0.23, 0.19, and 0.31m 3 / d (drug concentration 5%), the casing pressures of the three wells are 0.1, 0.2, and 0.15 MPa respectively, and the maximum dosing capacity of a dosing pump 2 is 5m 3 / d, the maximum pressure is 2.0Mpa to meet the needs of the site. In the middle of the three wells, the distances from the three wells are 79m, 102m and 158m respectively. The outlet of the dosing pump 2 is divided into three, and the flow meters are used to measure the three single wells. After the on-site dosing, the production is 7.5, 6.9 and 4.5m 3 / d, with a water content of 33-62%, and after 167 days of continuous use, the production of the three wells increased by 1,780 tons.

[0074] In a specific embodiment, when the power supply is unstable, it is necessary to store high-pressure gas to ensure the dosing operation of the oil well during the peak power supply period. The peak power period is 7 hours a day. The pressure rating of the high-pressure gas storage tank is 25 MPa, the storage pressure is 23 MPa, the minimum operating pressure is 1 MPa, and the volume of the high-pressure gas storage tank is 1m 3 , daily dosage 5-0.5m 3 / d, the high pressure gas storage tank can continuously add medicine for 12m 3 / d, to meet on-site needs.

[0075] In a specific embodiment, the pour point depressant was continuously added to the test. The crude oil contained 17.8% wax. Wax removal vehicles were used to remove wax. Chemical wax removal was subsequently used. Tank trucks were used to transport the wax remover to the wellhead every day and added through the casing. The effect was poor. Instead, the wellhead dosing device 100 was used to continuously add the wax remover on site. 0.4m 3 / d paraffin inhibitor solution was added evenly in four time periods and used on site for 754 days without any wax deposition at the wellhead.

[0076] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0077] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0078] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A wellhead dosing device, which adds chemicals into the well through the casing gate at the wellhead, characterized in that: include: A medicine storage tank (1) for containing medicine, wherein the medicine storage tank (1) is connected to the casing gate (10); A dosing pump (2), wherein a drug inlet end (21) of the dosing pump (2) is connected to the drug storage tank (1), and a drug outlet end (22) of the dosing pump (2) is connected to the casing gate (10); An air compressor (3) provides power for the dosing pump (2), and a high-pressure storage tank (31) is provided between the dosing pump (2) and the air compressor (3).

2. The wellhead dosing device according to claim 1, characterized in that: The dosing pump (2) comprises: Cylinder (201); A first piston (202) and a second piston (203) are axially movably arranged in the cylinder (201), and the first piston (202) and the second piston (203) are fixed to each other; A first power end (25) and a second power end (26) are respectively provided at both axial ends of the cylinder body (201), and the first power end (25) and the second power end (26) are both connected to the high-pressure storage tank (31) and the discharge pipe (32) via a reversing valve (27). The drug inlet end (21) and the drug outlet end (22) are both arranged on the side of the cylinder body (201) and located between the first piston (202) and the second piston (203). A first one-way valve (23) is provided at the drug inlet end (21) for only allowing fluid to flow into the cylinder body (201), and a second one-way valve (24) is provided at the drug outlet end (22) for only allowing fluid to flow out of the cylinder body (201).

3. The wellhead dosing device according to claim 2, characterized in that: A partition (204) is provided in the cylinder body (201) for separating the first piston (202) and the second piston (203); the drug inlet end (21) includes a first drug inlet pipe (211) and a second drug inlet pipe (212) respectively provided on both axial sides of the partition (204); and the drug outlet end (22) includes a first drug outlet pipe (221) and a second drug outlet pipe (222) respectively provided on both axial sides of the partition (204).

4. The wellhead dosing device according to claim 3, characterized in that: The first piston (202) and the second piston (203) are fixedly connected via a pull rod (205), and the pull rod (205) movably seals and passes through the partition (204).

5. The wellhead dosing device according to claim 3, characterized in that: The two first one-way valves (23) are respectively arranged on the first drug inlet pipe (211) and the second drug inlet pipe (212), and the two second one-way valves (24) are respectively arranged on the first drug outlet pipe (221) and the second drug outlet pipe (222).

6. The wellhead dosing device according to any one of claims 2 to 5, characterized in that: The reversing valve (27) comprises: a valve body (271), provided on the valve body (271) with a first port (273) connected to the first power end (25) or the second power end (26), a second port (274) connected to the high-pressure storage tank (31), and a third port (275) connected to the discharge pipe (32); a valve core (272) rotatably disposed within the valve body (271); In a first state, the valve core connects the first port (273) and the second port (274); In the second state, the valve core connects the first port (273) and the third port (275).

7. The wellhead dosing device according to claim 6, characterized in that: A sensor capable of detecting the positions of the first piston (202) and the second piston (203) is provided in the cylinder body (201), and the reversing valve (27) can perform an action in response to an electrical signal sent by the sensor.

8. The wellhead dosing device according to claim 7, characterized in that: The first power end (25) and the second power end (26) both extend into the cylinder body (201), and the two sensors are respectively arranged at the ends of the first power end (25) and the second power end (26) both extending into the cylinder body (201).

9. The wellhead dosing device according to any one of claims 1 to 5, characterized in that: The medicine storage tank (1) is connected to the casing gate (10) via a pressure balancing pipe (43), and the position where the pressure balancing pipe (43) is connected to the medicine storage tank (1) is higher than the liquid level in the medicine storage tank (1).

10. The wellhead dosing device according to claim 9, characterized in that: The drug outlet end (22) of the drug dosing pump (2) is connected to the sleeve gate (10) via a concentric tube (4), and the concentric tube (4) includes: An inner tube (41), wherein both ends of the inner tube (41) are respectively connected to the medicine outlet end (22) and the sleeve gate (10); An outer tube (42) is coaxially arranged outside the inner tube (41), one end of the outer tube (42) is fixedly connected to the inner tube (41), and the other end is connected to the casing gate (10), and the end of the pressure balance tube (43) away from the medicine storage tank (1) is connected to the outer tube (42).

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