An oil casing chemical dosing device

Abstract

This application relates to the technical field of oil drilling, and particularly to an oil casing dosing device, which includes a pipe body, a premixing mechanism, and an oil outlet mechanism; a medicine storage cavity for storing liquid medicine is provided on the pipe body, and the premixing mechanism includes a first piston, a second piston, a third piston, and a premixing plate. The second piston is slidably connected to the pipe body. An upper cavity is formed between the first piston and the second piston, and a lower cavity is formed between the second piston and the third piston; a mixing cavity is provided in the second piston, and a sliding groove is provided on the side wall of the second piston; a first one-way valve and a second one-way valve are installed on the pipe body, and a medicine inlet assembly and an oil inlet assembly are respectively provided on the second piston; the designed oil casing dosing device is convenient for stirring the mixed liquid of the liquid medicine and crude oil in the mixing cavity through a stirring rod, improving the mixing effect of the liquid medicine and crude oil, thereby improving the paraffin removal effect of the crude oil, and enabling the crude oil in the lower cavity and the liquid medicine in the upper cavity to intermittently enter the mixing cavity.

Description

Technical Field

[0001] The present application relates to the technical field of oil drilling, and particularly to an oil casing dosing device. Background Art

[0002] During the process of crude oil extraction, it is necessary to make the crude oil rise from the bottom of the well to the wellhead. During the flow of the crude oil from the bottom of the well to the wellhead, its pressure and temperature gradually decrease. When the temperature and pressure drop to the wax precipitation point, wax will precipitate from the crude oil, resulting in wax deposition during the flow of the crude oil along the wellbore. For the wax deposition phenomenon in oil wells, the current common wax removal measures mainly include chemical wax removal and thermal wax removal.

[0003] The patent document with the application number 201710595074.8 discloses an oil well dosing pump composed of a body, a piston rod, a sealing ring, an inlet and outlet valve, a pressure plate, a return spring, etc. A buffer device is provided between the upper end of the piston rod and the pressure plate, and an adjusting cap is sleeved on the piston rod and threadedly connected to the body. A buffer spring is arranged in the buffer cap of the buffer device, a guiding groove is opened on the buffer cap, and a positioning pin shaft is fixed to the piston rod and matches with the guiding groove. When the dosing pump piston rod is at the bottom dead center, the buffer device is in a compressed state, so that the piston rod can reach the bottom dead center in each stroke.

[0004] In view of the above related technologies, the applicant believes that during the process of injecting the chemical agent into the oil well, when the pumping unit moves upward, the return spring pushes the piston rod upward to return to its position, completing the suction and discharge of the chemical agent. However, after the chemical agent is injected into the crude oil, due to the high viscosity of the crude oil, the chemical agent is unevenly distributed in the crude oil, affecting the wax removal effect of the crude oil. Summary of the Invention

[0005] In order to improve the wax removal effect of crude oil, the present application provides an oil casing dosing device.

[0006] The oil casing dosing device provided by the present application adopts the following technical solutions:

[0007] An oil casing dosing device includes a pipe body, a premixing mechanism, and an oil outlet mechanism; a medicine storage cavity for storing liquid medicine is opened on the pipe body, and the medicine storage cavity is opened along the circumferential direction of the pipe body;

[0008] The premixing mechanism includes a first piston, a second piston, a third piston, and at least one premixing plate arranged from high to low in sequence. The first piston, the second piston, and the third piston are located in the inner cavity of the pipe body. The first piston and the third piston are both fixedly connected to the pipe body, the second piston is slidably connected to the pipe body. An upper cavity is formed between the first piston and the second piston, and a lower cavity is formed between the second piston and the third piston;

[0009] A mixing chamber is formed inside the second piston, and at least one sliding groove for the pre-mixing plate to slide is formed on the side wall of the second piston. The sliding groove is arranged along the axial direction of the second piston;

[0010] A first one-way valve and a second one-way valve are installed on the pipe body. The first one-way valve is used for the liquid medicine in the medicine storage chamber to flow into the upper cavity; the second one-way valve is used for the crude oil in the oil well to flow into the lower cavity;

[0011] A medicine inlet assembly and an oil inlet assembly are respectively arranged on the second piston. The medicine inlet assembly is used for the liquid medicine in the upper cavity to flow into the mixing chamber, and the oil inlet assembly is used for the crude oil in the lower cavity to flow into the mixing chamber;

[0012] The oil outlet mechanism is used for the mixture of the liquid medicine and the crude oil to be discharged along the pipe body and drives the second piston to slide along the pipe body.

[0013] By adopting the above technical solution, during the process of crude oil exploitation, the first one-way valve is adjusted so that the liquid medicine in the medicine storage chamber enters the upper cavity, and the second one-way valve is adjusted so that the oil in the oil well enters the lower cavity; the oil outlet mechanism is adjusted, and the oil outlet mechanism drives the second piston to slide along the axial direction of the pipe body. During the upward sliding process of the second piston, the distance between the second piston and the first piston is reduced, the volume of the upper cavity is reduced, and the liquid medicine in the upper cavity acts on the medicine inlet assembly, so that the liquid medicine in the upper cavity flows into the mixing chamber; during the downward sliding process of the second piston, the distance between the second piston and the third piston is reduced, the volume of the lower cavity is reduced, and the crude oil in the lower cavity acts on the oil inlet assembly, so that the crude oil in the lower cavity flows into the mixing chamber, realizing the intermittent entry of the crude oil in the lower cavity and the liquid medicine in the upper cavity into the mixing chamber. At the same time, during the movement of the second piston, the pre-mixing plate slides along the length direction of the sliding groove, blocking the flow of the liquid medicine and the crude oil in the mixing chamber, so that the movement trajectories of the liquid medicine and the crude oil change, realizing the stirring of the liquid medicine and the crude oil in the mixing chamber, and then the mixture of the liquid medicine and the crude oil in the mixing chamber is discharged through the oil outlet mechanism; the designed oil casing chemical adding device can facilitate the stirring of the mixture of the liquid medicine and the crude oil in the mixing chamber through the stirring rod, improve the mixing effect of the liquid medicine and the crude oil, and further improve the paraffin removal effect of the crude oil; and, by the intermittent entry of the crude oil in the lower cavity and the liquid medicine in the upper cavity into the mixing chamber, the entry of the crude oil into the upper cavity and the entry of the liquid medicine into the lower cavity are avoided.

[0014] Optionally, the pipe body includes an outer pipe, an inner pipe and a sealing ring. The inner pipe is located inside the outer pipe cavity, and the outer pipe and the inner pipe are coaxially arranged. The outer side wall of the sealing ring is connected to the inner side wall of the outer pipe, and the inner side wall of the sealing ring is connected to the outer side wall of the inner pipe. And the sealing ring is arranged close to the bottom wall of the inner pipe. The medicine storage chamber is formed by the outer pipe, the inner pipe and the sealing ring;

[0015] The first piston and the second piston are arranged in the inner tube. The first piston is fixedly connected to the inner tube, and the second piston is slidably connected to the inner tube. The premixing plate is fixedly connected to the inner tube; the third piston is fixedly connected to the outer tube.

[0016] By adopting the above technical solution, the medicine storage cavity formed by the inner tube, the outer tube and the sealing ring is convenient for storing the liquid medicine, enabling the separation of the mixed liquid and the liquid medicine; through the fixation of the first piston and the third piston, the total volume of the upper cavity, the lower cavity and the mixing cavity remains unchanged. As the second piston slides along the inner tube, the volumes of the upper cavity and the lower cavity are changed, realizing the change of the liquid pressure in the upper cavity and the lower cavity. Under the action of the liquid pressure, it is then convenient for the liquid medicine in the upper cavity and the oil liquid in the lower cavity to enter the mixing cavity.

[0017] Optionally, the distance between the premixing plate and the sealing ring is greater than the length of the sliding groove.

[0018] By adopting the above technical solution, the designed distance between the premixing plate and the sealing ring is greater than the length of the sliding groove, avoiding the communication between the sliding groove and the mixing cavity and ensuring the independent functions of the mixing cavity and the lower cavity.

[0019] Optionally, the premixing mechanism further includes a sealing plate and an infusion assembly for discharging the mixed liquid in the mixing cavity;

[0020] The sealing plate is fixedly connected to the inner tube, and the sealing plate is located directly above the first piston. The first piston and the sealing plate form a stirring cavity;

[0021] The infusion assembly includes a lifting rod. The lifting rod is coaxially arranged with the inner tube. The lifting rod passes through the sealing plate, the first piston and the second piston, and the lifting rod is slidably connected to the sealing plate and the first piston respectively. The lifting rod is fixedly connected to the second piston;

[0022] Liquid inlet holes and liquid outlet holes are formed in the lifting rod. The liquid inlet holes are located in the mixing cavity, and the mixing cavity is communicated with the inner cavity of the lifting rod through the liquid inlet holes; the liquid outlet holes are located in the stirring cavity, and the stirring cavity is communicated with the inner cavity of the lifting rod through the liquid outlet holes.

[0023] By adopting the above technical solution, the oil discharging mechanism is adjusted. Under the action of the oil discharging mechanism, the liquid medicine and the crude oil mixed liquid in the mixing cavity enter the inner cavity of the lifting rod along the liquid inlet holes and enter the stirring cavity along the liquid outlet holes, realizing the lifting of the liquid medicine and the crude oil mixed liquid; the designed premixing mechanism, through the sealing plate and the infusion assembly, is convenient for transporting the liquid medicine and the crude oil mixed liquid in the mixing cavity to the stirring cavity, realizing the lifting of the liquid medicine and the crude oil mixed liquid.

[0024] Optionally, it further includes a stirring mechanism for stirring the liquid medicine and crude oil mixture. The stirring mechanism is located in the stirring chamber. The stirring mechanism includes a lifting ring, a sliding block, and at least one group of stirring rods.

[0025] The lifting ring is sleeved on the lifting rod. The sliding block is arranged on the inner side wall of the lifting ring. A sliding groove for the sliding block to slide is formed on the lifting rod, and the sliding groove is arranged in a spiral shape.

[0026] One end of the stirring rod is connected to the outer side wall of the lifting ring, and the end of the stirring rod away from the lifting rod is rotatably connected to the inner tube.

[0027] By adopting the above technical solution, when the lifting rod is adjusted, during the lifting process of the lifting rod, since the stirring rod is rotatably connected to the inner tube and the sliding groove is arranged in a spiral shape, the sliding block slides along the sliding groove, thereby causing the lifting ring to rotate. The lifting ring drives the stirring rod to rotate, further stirring the liquid medicine and crude oil mixture in the stirring chamber, realizing the re - mixing of the liquid medicine and crude oil mixture, and further realizing the sufficient stirring of the liquid medicine and crude oil mixture. The designed stirring mechanism is convenient for further stirring the liquid medicine and crude oil mixture in the stirring chamber, making the liquid medicine and crude oil mixture mix more evenly. At the same time, through the lifting of the lifting rod, the mixing and stirring of the liquid medicine and crude oil mixture are realized under the combined action of the pre - mixing plate and the stirring rod.

[0028] Optionally, the stirring mechanism further includes a rotating ring and at least two sliders. The stirring rod is fixedly connected to the inner side wall of the rotating ring. The sliders are arranged on the outer side wall of the rotating ring. A sliding groove for the sliders to slide is formed on the inner side wall of the inner tube, and the sliding groove is arranged along the circumferential direction of the inner tube.

[0029] By adopting the above technical solution, when the lifting rod is adjusted, during the lifting process of the lifting rod, since the stirring rod is rotatably connected to the inner tube and the sliding groove is arranged in a spiral shape, the sliding block slides along the sliding groove, thereby causing the lifting ring to rotate. The lifting ring drives the stirring rod to rotate, the stirring rod drives the rotating ring to rotate, and the rotating ring drives the sliders to move along the sliding groove. The designed stirring mechanism realizes the limit of the rotating ring through the sliders and the sliding groove, avoids the rotating ring moving along the axial direction of the lifting rod, and further realizes the cooperation between the sliding block and the sliding groove, making the stirring rod rotate along the circumferential direction of the lifting rod, and realizing the mixing of the liquid medicine and crude oil mixture in the stirring chamber.

[0030] Optionally, the infusion assembly further includes a plug cover, a plug ball, and a third spring.

[0031] The plug cover is located above the plugging plate and is fixedly connected to the inner tube. A liquid storage cavity is formed between the plug cover and the plugging plate. The lifting rod penetrates through the plug cover, and the lifting rod is slidably connected to the plug cover.

[0032] The plugging plate is provided with a liquid inlet for communicating with the stirring chamber, and the third spring drives the plugging ball to plug the liquid inlet;

[0033] The plug cover is provided with a liquid discharge port for discharging the mixed liquid.

[0034] By adopting the above technical solution, the oil outlet mechanism is adjusted. Under the action of the oil outlet mechanism, the plugging ball applies a force to the third spring, causing the third spring to compress, and then separating the plugging ball from the plugging plate. At the same time, the stirring chamber is communicated with the liquid storage chamber. Meanwhile, the liquid medicine and crude oil mixed liquid in the stirring chamber flows into the liquid storage chamber along the liquid inlet, and the liquid medicine and crude oil mixed liquid in the liquid storage chamber is discharged along the liquid discharge port; the designed infusion assembly facilitates the liquid medicine and crude oil mixed liquid in the stirring chamber to enter the liquid storage chamber and be discharged along the liquid storage chamber; and, through the third spring and the plugging ball, the liquid medicine and crude oil mixed liquid enters the liquid storage chamber along the stirring chamber. When the oil outlet mechanism stops working, the third spring resets and pushes the plugging ball to plug the liquid inlet, realizing the one-way flow of the liquid medicine and crude oil mixed liquid.

[0035] Optionally, the plug cover includes a conical section and a horizontal section integrally arranged;

[0036] The plugging plate is arranged parallel to the horizontal section, the lifting rod is slidably connected to the horizontal section, and the third spring is connected to the horizontal section;

[0037] The horizontal section is connected to the small end of the conical section, and the large end of the conical section is fixedly connected to the inner tube. The liquid discharge port is located on the conical section.

[0038] By adopting the above technical solution, the plug cover arranged in sections, its conical section can connect the horizontal section and the inner tube. At the same time, it is convenient to gradually reduce the cross-sectional area of the flow of the liquid medicine and crude oil mixed liquid, thereby increasing the flow rate of the liquid medicine and crude oil mixed liquid; its horizontal section is convenient for installing the third spring and the lifting rod.

[0039] Optionally, the medicine feeding assembly is located in the inner cavity of the second piston. The medicine feeding assembly includes a first spring and a first seal. The top plate of the second piston is provided with a medicine feeding hole, the medicine feeding hole is arranged opposite to the first seal, and the top plate of the second piston and the first seal are connected by the first spring; the first spring drives the first seal to plug the medicine feeding hole.

[0040] By adopting the above technical solution, the oil outlet mechanism is adjusted. The oil outlet mechanism drives the second piston to move towards the first piston, reducing the volume of the upper cavity. The liquid medicine in the upper cavity exerts a force on the first seal, and the first spring elongates. As a result, the first seal is separated from the second piston, and the liquid medicine in the upper cavity flows into the mixing cavity along the medicine inlet hole. Subsequently, the oil outlet mechanism drives the second piston to move towards the third piston, gradually increasing the volume of the upper cavity. The first spring returns, and the first spring drives the first seal to move towards the top plate of the second piston to block the medicine inlet hole. The designed medicine inlet assembly facilitates the automatic entry of the liquid medicine in the upper cavity into the mixing cavity through the lifting of the second piston. At the same time, it facilitates the automatic blocking of the medicine inlet hole.

[0041] Optionally, the oil inlet assembly is located in the inner cavity of the second piston. The oil inlet assembly includes a second spring and a second seal. An oil inlet hole is formed in the bottom plate of the second piston, and the oil inlet hole is arranged opposite to the second seal. The bottom plate of the second piston is connected to the second seal through the second spring. The second spring drives the second seal to block the oil inlet hole.

[0042] By adopting the above technical solution, the oil outlet mechanism is adjusted. The oil outlet mechanism drives the second piston to move towards the third piston, reducing the volume of the lower cavity. The crude oil in the lower cavity exerts a force on the second seal, and the second spring elongates. As a result, the second seal is separated from the second piston, and the crude oil in the lower cavity flows into the mixing cavity along the oil inlet hole. Subsequently, the oil outlet mechanism drives the second piston to move towards the first piston, gradually increasing the volume of the lower cavity. The second spring returns, and the second spring drives the second seal to move towards the bottom plate of the second piston to block the oil inlet hole. The designed oil inlet assembly facilitates the automatic entry of the crude oil in the lower cavity into the mixing cavity through the descent of the second piston. At the same time, it facilitates the automatic blocking of the oil inlet hole.

[0043] In summary, the present application includes at least one of the following beneficial technical effects:

[0044] 1. The designed oil casing medicine adding device facilitates the stirring of the mixed liquid of the liquid medicine and the crude oil in the mixing cavity through the stirring rod, improving the mixing effect of the liquid medicine and the crude oil, and further improving the paraffin removal effect of the crude oil. Moreover, by the intermittent entry of the crude oil in the lower cavity and the liquid medicine in the upper cavity into the mixing cavity, the entry of the crude oil into the upper cavity and the entry of the liquid medicine into the lower cavity are avoided.

[0045] 2. The designed oil casing medicine adding device facilitates the further stirring of the mixed liquid of the liquid medicine and the crude oil in the stirring cavity through the stirring mechanism, making the mixed liquid of the liquid medicine and the crude oil more evenly mixed. At the same time, through the lifting of the lifting rod, the combined action of the pre-mixing plate and the stirring rod realizes the mixing and stirring of the mixed liquid of the liquid medicine and the crude oil.

[0046] 3. The designed chemical dosing device for oil casing facilitates the automatic entry of the liquid medicine in the upper cavity and the crude oil in the lower cavity into the mixing cavity during the upward or downward movement of the second piston along the inner tube through the medicine inlet assembly and the oil inlet assembly. Meanwhile, it facilitates the automatic sealing of the medicine inlet hole and the oil inlet hole. Brief Description of the Drawings

[0047] Figure 1 is the overall structural schematic diagram of the chemical dosing device for oil casing in Embodiment 1 of the present application;

[0048] Figure 2 is the cross-sectional view of the chemical dosing device for oil casing in Embodiment 1 of the present application;

[0049] Figure 3 is Figure 2 the enlarged schematic diagram of Part A of

[0050] Figure 4 is Figure 2 the enlarged schematic diagram of Part B of

[0051] Figure 5 is Figure 2 the enlarged schematic diagram of Part C of

[0052] Figure 6 is Figure 2 the enlarged schematic diagram of Part D of

[0053] Description of the Reference Numerals: 1, pipe body; 11, outer pipe; 12, inner pipe; 13, sealing ring; 14, medicine storage cavity; 15, first one-way valve; 151, first cylindrical plug; 152, fourth spring; 153, first concave cavity; 154, first connecting earring; 155, first sliding rod; 156, medicine through hole; 16, second one-way valve; 161, second cylindrical plug; 162, fifth spring; 163, second connecting earring; 164, second concave cavity; 165, oil through hole; 166, second sliding rod; 2, premixing mechanism; 21, third piston; 22, second piston; 221, mixing cavity; 222, sliding groove; 223, medicine inlet assembly; 2231, first seal; 2232, first spring; 2233, medicine inlet hole; 224, oil inlet assembly; 2241, second seal; 2242, second spring; 2243, oil inlet hole; 225, premixing plate; 23, first piston; 24, sealing plate; 25, liquid infusion assembly; 251, lifting rod; 2511, liquid inlet hole; 2512, liquid outlet hole; 252, plug cover; 2521, horizontal section; 2522, conical section; 253, liquid inlet; 254, sealing ball; 255, third spring; 256, liquid discharge port; 26, lower cavity; 27, upper cavity; 28, stirring cavity; 29, liquid storage cavity; 3, stirring mechanism; 31, lifting ring; 32, sliding block; 33, sliding groove; 34, stirring rod; 35, rotating ring; 36, slider; 37, sliding groove. Detailed implementation mode

[0054] The following will further describe the present application in detail with reference to the Figures 1-6 accompanying drawings.

[0055] An embodiment of the present application discloses an oil casing dosing device.

[0056] Referring to Figure 1 and Figure 2 , an oil casing dosing device includes a pipe body 1, a premixing mechanism 2 for premixing crude oil and liquid medicine, a stirring mechanism 3 for stirring the mixture of liquid medicine and crude oil, and an oil discharging mechanism for discharging the mixture of liquid medicine and crude oil along the pipe body 1 and driving a second piston 22 to slide along the pipe body 1; the pipe body 1 includes an outer pipe 11, an inner pipe 12 and a sealing ring 13. The inner pipe 12 and the sealing ring 13 are located in the inner cavity of the outer pipe 11, and the outer pipe 11, the inner pipe 12 and the sealing ring 13 are coaxially arranged. The outer side wall of the sealing ring 13 is connected to the inner side wall of the outer pipe 11, and the inner side wall of the sealing ring 13 is connected to the outer side wall of the inner pipe 12. The connection mode between the sealing ring 13 and the inner pipe 12 and the connection mode between the sealing ring 13 and the outer pipe 11 are welding. The sealing ring 13 is arranged close to the bottom wall of the inner pipe 12. The outer pipe 11, the inner pipe 12 and the sealing ring 13 form a medicine storage cavity 14 for storing liquid medicine. The medicine storage cavity 14 is arranged along the circumferential direction of the pipe body 1; a first one-way valve 15 and a second one-way valve 16 are installed on the pipe body 1.

[0057] Referring to Figure 2, the premixing mechanism 2 includes a first piston 23, a second piston 22, a third piston 21, a sealing plate 24, an infusion assembly 25, and at least one premixing plate 225; the first piston 23, the second piston 22, and the third piston 21 are arranged in sequence from high to low. The first piston 23 and the second piston 22 are both located in the inner cavity of the inner tube 12, and both the first piston 23 and the third piston 21 are fixedly connected to the inner tube 12. In this embodiment, the first piston 23 and the inner tube 12 and the third piston 21 and the inner tube 12 are both welded. The second piston 22 is located in the inner cavity of the outer tube 11, and the second piston 22 is slidably connected to the inner tube 12; an upper cavity 27 is formed between the first piston 23 and the second piston 22, and a lower cavity 26 is formed between the second piston 22 and the third piston 21; a mixing cavity 221 is formed inside the second piston 22, and at least one sliding groove 222 for the premixing plate 225 to slide is formed on the side wall of the second piston 22. The sliding groove 222 in this application can be two, three, or four. As long as the crude oil and the liquid medicine in the mixing cavity 221 can be fully mixed by the premixing plate 225, three sliding grooves 222 are provided in this embodiment, and the three sliding grooves 222 are evenly distributed along the circumferential direction of the second piston 22, and each sliding groove 222 is arranged along the axial direction of the second piston 22. The distance between the premixing plate 225 and the sealing ring 13 is greater than the length of the sliding groove 222; in this application, the premixing plate 225 is arranged corresponding to the sliding groove 222, and three premixing plates 225 are provided. The three premixing plates 225 are evenly distributed along the circumferential direction of the inner tube 12, and the premixing plate 225 is welded to the inner tube 12. The premixing plate 225 passes through the sliding groove 222 and extends into the mixing cavity 221, so as to realize the full mixing of the crude oil and the liquid medicine in the mixing cavity 221 during the process of the second piston 22 sliding along the inner tube 12.

[0058] Refer to Figure 3 and Figure 4, a first one-way valve 15 is installed on the inner tube 12. The first one-way valve 15 is used for the liquid medicine in the medicine storage cavity 14 to flow into the upper cavity 27. The first one-way valve 15 includes a fourth spring 152 and a first cylindrical plug 151. The first cylindrical plug 151 is arranged along the radial direction of the inner tube 12. A first connecting earring 154 is welded on the outer side wall of the first cylindrical plug 151. The first cylindrical plug 151 and the first connecting earring 154 are coaxially arranged. A first sliding rod 155 is welded on the inner side wall of the inner tube 12. The first sliding rod 155 is arranged along the radial direction of the inner tube 12. The first sliding rod 155 penetrates through the first connecting earring 154, and the first sliding rod 155 is slidably connected with the first connecting earring 154. A first concave cavity 153 is opened on one side of the first cylindrical plug 151 close to the inner tube 12. A medicine through hole 156 for communicating the medicine storage cavity 14 and the upper cavity 27 is opened on the inner tube 12, and the medicine through hole 156 is arranged opposite to the first concave cavity 153. One end of the fourth spring 152 is welded to the cavity wall of the first concave cavity 153, and the other end is welded to the inner wall of the inner tube 12. The fourth spring 152 drives the first cylindrical plug 151 to move towards the inner tube 12 side to block the medicine through hole 156.

[0059] Refer to Figure 3 and Figure 4 , a second one-way valve 16 is installed on the outer tube 11. The second one-way valve 16 is used for the crude oil in the oil well to flow into the lower cavity 26. The second one-way valve 16 includes a fifth spring 162 and a second cylindrical plug 161. The second cylindrical plug 161 is arranged along the radial direction of the outer tube 11. A second connecting earring 163 is welded on the outer side wall of the second cylindrical plug 161. The second cylindrical plug 161 and the second connecting earring 163 are coaxially arranged. A second sliding rod 166 is welded on the inner side wall of the outer tube 11. The second sliding rod 166 is arranged along the radial direction of the outer tube 11. The second sliding rod 166 penetrates through the second connecting earring 163, and the second sliding rod 166 is slidably connected with the second connecting earring 163. A second concave cavity 164 is opened on one side of the second cylindrical plug 161 close to the outer tube 11. An oil through hole 165 for communicating the oil well and the lower cavity 26 is opened on the outer tube 11, and the oil through hole 165 is arranged opposite to the second concave cavity 164. One end of the fifth spring 162 is welded to the cavity wall of the second concave cavity 164, and the other end is welded to the inner wall of the outer tube 11. The fifth spring 162 drives the second cylindrical plug 161 to move towards the outer tube 11 side to block the oil through hole 165.

[0060] Refer to Figure 2 and Figure 4, a medicine inlet assembly 223 and an oil inlet assembly 224 are respectively arranged on the second piston 22. The medicine inlet assembly 223 is used for the liquid medicine in the upper cavity 27 to flow into the mixing cavity 221. The medicine inlet assembly 223 is located in the inner cavity of the second piston 22. The medicine inlet assembly 223 includes a first spring 2232 and a first seal 2231. A medicine inlet hole 2233 is formed in the top plate of the second piston 22. The medicine inlet hole 2233 is arranged opposite to the first seal 2231, and the top plate of the second piston 22 is connected to the first seal 2231 through the first spring 2232. The first seal 2231 includes a first seal ring and a first seal cover which are integrally connected. The first seal ring is located on the side of the first seal cover close to the top plate of the second piston 22, and the first seal ring is arranged opposite to the medicine inlet hole 2233. One end of the first spring 2232 is welded to the first seal cover, and the other end extends out of the first seal ring and is welded to the top plate of the second piston 22. The first spring 2232 drives the first seal ring and the second seal cover to block the medicine inlet hole 2233.

[0061] Refer to Figure 2 and Figure 3 , the oil inlet assembly 224 is used for the crude oil in the lower cavity 26 to flow into the mixing cavity 221. The oil inlet assembly 224 is located in the inner cavity of the second piston 22. The oil inlet assembly 224 includes a second spring 2242 and a second seal 2241. An oil inlet hole 2243 is formed in the bottom plate of the second piston 22. The oil inlet hole 2243 is arranged opposite to the second seal 2241, and the bottom plate of the second piston 22 is connected to the second seal 2241 through the second spring 2242. The second seal 2241 includes a second seal ring and a second seal cover which are integrally connected. The second seal ring is located on the side of the second seal cover close to the bottom plate of the second piston 22, and the second seal ring is arranged opposite to the liquid inlet hole 2511. One end of the second spring 2242 is welded to the second seal cover, and the other end extends out of the second seal ring and is welded to the bottom plate of the second piston 22. The second spring 2242 drives the second seal ring and the second plugging plate 24 to block the liquid inlet hole 2511.

[0062] Refer to Figure 2 , the plugging plate 24 is fixedly connected to the inner tube 12, and in this embodiment, the plugging plate 24 is welded to the inner tube 12. The plugging plate 24 is located directly above the first piston 23, and the plugging plate 24, the first piston 23 and the third piston 21 are arranged in parallel. The first piston 23 and the plugging plate 24 form a stirring cavity 28.

[0063] Refer to Figure 2, the infusion assembly 25 is used for discharging the mixed liquid in the mixing chamber 221. The infusion assembly 25 includes a lifting rod 251, a plug cover 252, a plugging ball 254 and a third spring 255. The lifting rod 251 is coaxially arranged with the inner tube 12. The plug cover 252 is located above the plugging plate 24. The plug cover 252 includes a conical section 2522 and a horizontal section 2521 which are integrally arranged, and the conical section 2522 is integrally connected to the horizontal section 2521; the horizontal section 2521 is integrally connected to the small end of the conical section 2522, and the large end of the conical section 2522 is welded to the inner tube 12. The plugging plate 24 is arranged parallel to the horizontal section 2521; the lifting rod 251 passes through the horizontal section 2521, the plugging plate 24, the first piston 23 and the second piston 22. The lifting rod 251 is slidably connected to the horizontal section 2521, the plugging plate 24 and the first piston 23, and the lifting rod 251 is fixedly connected to the second piston 22; liquid inlet holes 2511 and liquid outlet holes 2512 are formed in the lifting rod 251. The liquid inlet holes 2511 are located in the mixing chamber 221, and the mixing chamber 221 is communicated with the inner cavity of the lifting rod 251 through the liquid inlet holes 2511. The liquid outlet holes 2512 are located in the stirring chamber 28, and the stirring chamber 28 is communicated with the inner cavity of the lifting rod 251 through the liquid outlet holes 2512.

[0064] Refer to Figure 2 , a liquid storage chamber 29 is formed between the plug cover 252 and the plugging plate 24. A liquid inlet 253 for communicating with the stirring chamber 28 is formed in the plugging plate 24. One end of the third spring 255 is welded to the horizontal section 2521, and the other end is welded to the plugging ball 254. The third spring 255 drives the plugging ball 254 to block the liquid inlet 253; a liquid discharge port 256 for discharging the mixed liquid is formed in the conical section 2522.

[0065] Refer to Figure 5 and Figure 6, the stirring mechanism 3 is located inside the stirring chamber 28. The stirring mechanism 3 includes a lifting ring 31, a rotating ring 35, a sliding block 32, at least one set of stirring rods 34, and at least two sliders 36. The lifting ring 31 is sleeved on the lifting rod 251. The sliding block 32 is arranged on the inner side wall of the lifting ring 31 and is welded to the lifting ring 31. A sliding groove 33 for the sliding block 32 to slide is formed on the lifting rod 251, and the sliding groove 33 is arranged in a spiral shape. In this embodiment, the sliding block 32 is arranged in a hemispherical shape to facilitate the sliding of the sliding block 32 along the sliding groove 33. A rotating ring 35 is arranged on the outer periphery of the lifting ring 31. The stirring rods 34 are located between the lifting ring 31 and the rotating ring 35. In this application, the stirring rods 34 can be set to one group, two groups, or three groups. As long as the stable connection between the rotating ring 35 and the lifting ring 31 is achieved and the sufficient mixing of the crude oil and the liquid medicine is facilitated. In this embodiment, two groups of stirring rods 34 are provided, and the two groups of stirring rods 34 are arranged at both ends close to the rotating ring 35. Each group of stirring rods 34 is set to three. The three stirring rods 34 are evenly distributed along the circumferential direction of the rotating ring 35. One end of each stirring rod 34 is welded to the rotating ring 35, and the other end is welded to the lifting ring 31. And each stirring rod 34 is arranged along the radial direction of the lifting ring 31. A sliding groove 37 for the slider 36 to slide is formed on the inner side wall of the inner tube 12. The sliding groove 37 is arranged along the circumferential direction of the inner tube 12. In this application, the slider 36 can be two, three, or four. As long as the sliding connection between the slider 36 and the sliding groove 37 and the stable connection between the rotating ring 35 and the inner tube 12 are achieved. In order to ensure the rotational connection between the rotating ring 35 and the inner tube 12 and reduce the production cost, in this embodiment, three sliders 36 are provided, and the three sliders 36 are evenly distributed along the circumferential direction of the rotating ring 35, and the sliders 36 are welded to the outer side wall of the rotating ring 35.

[0066] Referring to Figure 1 and Figure 2 , the oil outlet mechanism includes a double-acting reciprocating pump installed on the pipe body 1. The piston rod of the double-acting reciprocating pump is coaxially connected to the lifting rod 251, and the piston rod of the double-acting reciprocating pump is connected to the lifting rod 251 through a coupling. The liquid inlet pipe of the double-acting reciprocating pump is connected to the conical section 2522 through a pipeline, and the pipeline is connected to the conical section 2522 through a flange. One end of the pipeline away from the double-acting reciprocating pump is installed at the liquid discharge port 256 of the conical section 2522, and the inner cavity of the pipeline is communicated with the liquid storage chamber 29 through the liquid discharge port 256.

[0067] The implementation principle of a chemical dosing device for oil casings in an embodiment of this application is as follows: During the crude oil extraction process, the double-acting reciprocating pump is adjusted. Under the action of the double-acting reciprocating pump, when the lifting rod 251 moves upward, the lifting rod 251 drives the second piston 22 to move upward. During the upward movement of the second piston 22, the second cylindrical plug 161 moves away from the oil passage hole 165, the fifth spring 162 is stretched, the lower cavity 26 is communicated with the oil well, and crude oil flows into the lower cavity 26; when the lifting rod 251 moves downward, the lifting rod 251 drives the second piston 22 to move downward. Under the action of the fifth spring 162, the second cylindrical plug 161 resets to block the oil passage hole 165. During the downward movement of the second piston 22, the first cylindrical plug 151 moves away from the chemical dosing hole 156, the fourth spring 152 is stretched, the upper cavity 27 is communicated with the chemical storage cavity 14, and the chemical liquid flows into the upper cavity 27. When the lifting rod 251 moves upward, the lifting rod 251 drives the second piston 22 to move upward. Under the action of the fourth spring 152, the first cylindrical plug 151 resets to block the chemical dosing hole 156. Through the reciprocating lifting of the lifting rod 251, the reciprocating lifting of the second piston 22 is driven, so that the crude oil intermittently enters the lower cavity 26, and the chemical liquid intermittently enters the upper cavity 27.

[0068] During the lifting of the lifting rod 251, the lifting rod 251 drives the second piston 22 to slide along the axial direction of the inner tube 12. During the upward sliding of the second piston 22, the distance between the second piston 22 and the first piston 23 decreases, the volume of the upper cavity 27 decreases, and the chemical liquid in the upper cavity 27 exerts force on the first sealing cover and the first sealing ring, so that the upper cavity 27 is communicated with the mixing cavity 221, and the chemical liquid in the upper cavity 27 enters the mixing cavity 221; during the downward sliding of the second piston 22, the distance between the second piston 22 and the third piston 21 decreases, the volume of the lower cavity 26 decreases, and the crude oil in the lower cavity 26 exerts force on the second sealing cover and the second sealing ring, so that the lower cavity 26 is communicated with the mixing cavity 221, and the crude oil in the lower cavity 26 enters the mixing cavity 221. And under the action of the first spring 2232, the first spring 2232 drives the first sealing cover and the first sealing ring to reset to block the liquid inlet hole 2511; the lifting rod 251 drives the second piston 22 to slide along the axial direction of the inner tube 12. During the upward sliding of the second piston 22, under the action of the second spring 2242, the second spring 2242 drives the second sealing cover and the second sealing ring to reset to block the chemical liquid inlet hole 2233. Through the reciprocating lifting of the lifting rod 251, the reciprocating lifting of the second piston 22 is driven, so that the crude oil in the lower cavity 26 and the chemical liquid in the upper cavity 27 intermittently enter the mixing cavity 221.

[0069] Under the action of the double-acting reciprocating pump, the mixed liquid of crude oil and liquid medicine in the mixing chamber 221 enters the inner cavity of the lifting rod 251 along the liquid inlet hole 2511, and the mixed liquid of crude oil and liquid medicine in the inner cavity of the lifting rod 251 then enters the stirring chamber 28 along the liquid outlet hole 2512.

[0070] During the lifting process of the lifting rod 251, due to the action of the sliding groove 33, the sliding block 32 slides along the track of the sliding groove 33, which in turn causes the lifting ring 31 to rotate. The lifting ring 31 drives the stirring rod 34 to rotate, the stirring rod 34 drives the rotating ring 35 to rotate, and the rotating ring 35 drives the slider 36 to slide along the sliding groove 37, realizing further stirring of the mixed liquid of crude oil and liquid medicine in the stirring rod 34. At the same time, under the action of the double-acting reciprocating pump, the liquid in the stirring chamber 28 exerts a force on the plugging ball 254, causing the plugging ball 254 to separate from the plugging plate 24. The mixed liquid of crude oil and liquid medicine in the stirring chamber 28 enters the liquid storage chamber 29 along the liquid inlet 253, and the liquid in the liquid storage chamber 29 is discharged along the liquid discharge port 256, realizing the discharge of the mixed liquid of crude oil and liquid medicine.

[0071] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. An oil casing chemical dosing device, characterized in that, It includes a tube body (1), a premixing mechanism (2), and an oil outlet mechanism; a medicine storage cavity (14) for storing liquid medicine is formed on the tube body (1), and the medicine storage cavity (14) is formed along the circumferential direction of the tube body (1). The premixing mechanism (2) includes a first piston (23), a second piston (22), and a third piston (21) arranged in sequence from high to low, and at least one premixing plate (225). The first piston (23), the second piston (22), and the third piston (21) are located in the inner cavity of the tube body (1). The first piston (23) and the third piston (21) are both fixedly connected to the tube body (1), the second piston (22) is slidably connected to the tube body (1), an upper cavity (27) is formed between the first piston (23) and the second piston (22), and a lower cavity (26) is formed between the second piston (22) and the third piston (21). A mixing cavity (221) is formed in the second piston (22), and at least one sliding groove (222) for the premixing plate (225) to slide is formed on the side wall of the second piston (22). The sliding groove (222) is arranged along the axial direction of the second piston (22). A first one-way valve (15) and a second one-way valve (16) are installed on the tube body (1). The first one-way valve (15) is used for the liquid medicine in the medicine storage cavity (14) to flow into the upper cavity (27); the second one-way valve (16) is used for the crude oil in the oil well to flow into the lower cavity (26). An medicine inlet assembly (223) and an oil inlet assembly (224) are respectively arranged on the second piston (22). The medicine inlet assembly (223) is used for the liquid medicine in the upper cavity (27) to flow into the mixing cavity (221), and the oil inlet assembly (224) is used for the crude oil in the lower cavity (26) to flow into the mixing cavity (221). The oil outlet mechanism is used for the mixed liquid of the liquid medicine and the crude oil to be discharged along the tube body (1) and to drive the second piston (22) to slide along the tube body (1).

2. The chemical dosing device for oil casings according to claim 1, wherein, The tube body (1) includes an outer tube (11), an inner tube (12), and a sealing ring (13). The inner tube (12) is located in the inner cavity of the outer tube (11), and the outer tube (11) and the inner tube (12) are coaxially arranged. The outer side wall of the sealing ring (13) is connected to the inner side wall of the outer tube (11), the inner side wall of the sealing ring (13) is connected to the outer side wall of the inner tube (12), and the sealing ring (13) is arranged close to the bottom wall of the inner tube (12). The medicine storage cavity (14) is formed by the outer tube (11), the inner tube (12), and the sealing ring (13). The first piston (23) and the second piston (22) are arranged in the inner tube (12). The first piston (23) is fixedly connected to the inner tube (12), the second piston (22) is slidably connected to the inner tube (12), and the premixing plate (225) is fixedly connected to the inner tube (12); the third piston (21) is fixedly connected to the outer tube (11).

3. The oil casing chemical dosing device according to claim 2, characterized in that, The distance between the premixing plate (225) and the sealing ring (13) is greater than the length of the sliding groove (222).

4. The oil casing dosing device according to claim 2, wherein, The premixing mechanism (2) further includes a sealing plate (24) and an infusion assembly (25) for discharging the mixed liquid in the mixing chamber (221); The sealing plate (24) is fixedly connected to the inner tube (12), and the sealing plate (24) is located directly above the first piston (23). The first piston (23) and the sealing plate (24) form a stirring chamber (28); The infusion assembly (25) includes a lifting rod (251). The lifting rod (251) is coaxially arranged with the inner tube (12). The lifting rod (251) passes through the sealing plate (24), the first piston (23) and the second piston (22). The lifting rod (251) is slidably connected to the sealing plate (24) and the first piston (23) respectively, and the lifting rod (251) is fixedly connected to the second piston (22); The lifting rod (251) is provided with a liquid inlet hole (2511) and a liquid outlet hole (2512). The liquid inlet hole (2511) is located in the mixing chamber (221), and the mixing chamber (221) is communicated with the inner cavity of the lifting rod (251) through the liquid inlet hole (2511); The liquid outlet hole (2512) is located in the stirring chamber (28), and the stirring chamber (28) is communicated with the inner cavity of the lifting rod (251) through the liquid outlet hole (2512).

5. The chemical dosing device for oil casing according to claim 4, wherein, It further includes a stirring mechanism (3) for stirring the mixed liquid of the liquid medicine and the crude oil. The stirring mechanism (3) is located in the stirring chamber (28). The stirring mechanism (3) includes a lifting ring (31), a sliding block (32) and at least one group of stirring rods (34); The lifting ring (31) is sleeved on the lifting rod (251). The sliding block (32) is arranged on the inner side wall of the lifting ring (31). The lifting rod (251) is provided with a sliding groove (33) for the sliding block (32) to slide, and the sliding groove (33) is arranged in a spiral shape; One end of the stirring rod (34) is connected to the outer side wall of the lifting ring (31), and the end of the stirring rod (34) far from the lifting rod (251) is rotatably connected to the inner tube (12).

6. The oil casing dosing device according to claim 5, wherein, The stirring mechanism (3) further includes a rotating ring (35) and at least two sliders (36). The stirring rod (34) is fixedly connected to the inner side wall of the rotating ring (35). The sliders (36) are arranged on the outer side wall of the rotating ring (35). The inner side wall of the inner tube (12) is provided with a sliding groove (37) for the sliders (36) to slide, and the sliding groove (37) is arranged along the circumferential direction of the inner tube (12).

7. The downhole tubing chemical dosing device according to claim 4, characterized in that, The infusion assembly (25) further includes a plug cover (252), a sealing ball (254) and a third spring (255); The plug cap (252) is located above the plugging plate (24), and the plug cap (252) is fixedly connected to the inner tube (12). A liquid storage cavity (29) is formed between the plug cap (252) and the plugging plate (24). The lifting rod (251) is arranged through the plug cap (252), and the lifting rod (251) is slidably connected to the plug cap (252). A liquid inlet (253) for communicating with the stirring cavity (28) is formed in the plugging plate (24), and the third spring (255) drives the plugging ball (254) to block the liquid inlet (253). A liquid discharge port (256) for discharging the mixed liquid is formed in the plug cap (252).

8. The oil casing dosing device according to claim 7, wherein, The plug cap (252) includes a conical section (2522) and a horizontal section (2521) which are integrally arranged. The plugging plate (24) is arranged parallel to the horizontal section (2521). The lifting rod (251) is slidably connected to the horizontal section (2521), and the third spring (255) is connected to the horizontal section (2521). The horizontal section (2521) is connected to the small - end of the conical section (2522), and the large - end of the conical section (2522) is fixedly connected to the inner tube (12). The liquid discharge port (256) is located on the conical section (2522).

9. The oil casing chemical dosing device according to claim 1, characterized in that, The medicine inlet assembly (223) is located in the inner cavity of the second piston (22). The medicine inlet assembly (223) includes a first spring (2232) and a first seal (2231). A medicine inlet hole (2233) is formed in the top plate of the second piston (22). The medicine inlet hole (2233) is arranged opposite to the first seal (2231), and the top plate of the second piston (22) is connected to the first seal (2231) through the first spring (2232). The first spring (2232) drives the first seal (2231) to block the medicine inlet hole (2233).

10. The chemical dosing device for oil casing according to claim 1, characterized in that, The oil inlet assembly (224) is located in the inner cavity of the second piston (22). The oil inlet assembly (224) includes a second spring (2242) and a second seal (2241). An oil inlet hole (2243) is formed in the bottom plate of the second piston (22). The oil inlet hole (2243) is arranged opposite to the second seal (2241), and the bottom plate of the second piston (22) is connected to the second seal (2241) through the second spring (2242). The second spring (2242) drives the second seal (2241) to block the oil inlet hole (2243).

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