Downhole sampler for polymer flooding injection well

Abstract

The invention discloses an underground sampler for a polymer flooding injection well, which belongs to the technical field of underground polymer sampling and comprises a shell and a connecting cap, a connector is mounted at one end of the shell, a lower joint is mounted at the other end of the shell, and a locking mechanism is arranged in an inner cavity at the joint of the lower joint and the shell. An execution mechanism is arranged at the end, close to the connector, of the inner cavity of the shell, power is provided through the circuit board, the circuit board supplies power to a coil in the execution mechanism to generate an electromagnetic field, and the electromagnetic field drives the static magnet and the movable magnet to move downwards. By means of cooperation of a pressure spring, a pull rod and a cam in the locking mechanism, when the lower piston moves downwards, the pull rod and the cam are driven to be connected in a clamped mode through the pressure spring, and then the upper piston, the connecting rod and the lower piston in the moving mechanism are driven to move downwards to close a port in the connecting position of the sampling sleeve and the lower connector. Therefore, the downward moving action of the moving mechanism can be locked, the moving mechanism is prevented from rebounding, and the lower port of the sampling sleeve is closed.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole polymer sampling, and particularly to a downhole sampler for polymer flooding injection wells. Background Technique

[0002] A polymer is called a high molecular compound, abbreviated as a macromolecule, also known as a high molecular polymer. Generally, it refers to a compound with a relative molecular mass as high as several thousand to several million. The vast majority of high molecular compounds are mixtures of many homologues with different relative molecular masses. Therefore, the relative molecular mass of a high molecular compound is the average relative molecular mass.

[0003] At present, polymer flooding injection wells can only rely on sampling points set in the surface process for sampling and analysis to provide a basis for judging the injection quality and adjusting the plan. However, it is impossible to sample online along the more than one thousand - meter pipe string in the downhole of the injection well, and the downhole polymer state, viscosity loss, and chemical agent content cannot be analyzed and judged. To solve the above - mentioned problems, we have proposed a downhole sampler for polymer flooding injection wells.

[0004] A downhole negative - pressure sampler proposed according to the publication number: CN217586504U includes an upper ball seat, a lower ball seat, and a sampling cylinder arranged between the upper ball seat and the lower ball seat. A hydraulic piston is inserted into the upper port of the upper ball seat, and a hydraulic cylinder is sleeved outside the hydraulic piston. The upper end of the hydraulic cylinder is connected to the cylinder body, and an upper joint is arranged at the upper end of the cylinder body; a piston with a pull rod is arranged in the cylinder body, and the lower end of the pull rod is fixedly connected to the locking block of the hydraulic piston through a ratchet; an upper spring is sleeved outside the pull rod, the upper end of the upper spring touches the piston, and the lower end of the upper spring is fixed in the cylinder body below the piston. This application can solve the problem of difficult sampling at the position where well testing encounters resistance, provide strong support for analyzing the cause of resistance, formulating targeted treatment and prevention measures, and ensure the successful acquisition of well - testing data and data quality.

[0005] According to the above introduction, it is very difficult to sample existing downhole polymers at present. It can only rely on sampling points set in the surface process for sampling and analysis to provide a basis for judging the injection quality and adjusting the plan. However, it is impossible to sample online along the more than one - thousand - meter pipe string in the downhole of the injection well, resulting in the inability to analyze and judge the downhole polymer state, viscosity loss, and chemical agent content. Summary of the Invention

[0006] The purpose of the present invention is to provide a downhole sampler for polymer flooding injection wells, which realizes sampling of polymer solutions at different depths more than one thousand meters downhole, can timely and accurately understand the working viscosity of polymers at any depth in the wellbore and the state of polymer fluids, and provides a basis for viscosity loss control and plan adjustment. This instrument has a low cost and strong operability, so as to solve the problems raised in the above - mentioned background technique.

[0007] To achieve the above object, the present invention provides the following technical solution: A downhole sampler for polymer flooding injection wells, comprising a housing and a connecting cap. One end of the housing is provided with a connecting head, the connecting cap is installed on the connecting head, a rope cap is installed on the outer side of one end of the connecting head, and a lower joint is installed at the other end of the housing. A locking mechanism is arranged in the inner cavity at the connection between the lower joint and the housing. An actuating mechanism is arranged at one end of the inner cavity of the housing close to the connecting head. A moving mechanism is arranged on the side facing each other between the actuating mechanism and the locking mechanism. The moving mechanism is arranged in the inner cavity of the housing. The connecting head is provided with a cavity, and a circuit board is installed in the cavity of the connecting head.

[0008] Preferably, the housing includes an upper connecting sleeve, a lower connecting sleeve and a sampling sleeve. The upper connecting sleeve is fixedly connected to the other end of the connecting head. Both ends of the lower connecting sleeve are fixedly connected to the upper connecting sleeve and one end of the sampling sleeve respectively. The other end of the sampling sleeve is fixedly connected to one end of the lower joint.

[0009] Preferably, the actuating mechanism includes a coil bobbin. The coil bobbin is installed in the inner cavity of the upper connecting sleeve. A coil is wound on the surface of the coil bobbin. A static magnet is installed at one end of the inner cavity of the coil bobbin, and a moving magnet is installed at the other end of the inner cavity of the coil bobbin. One end of the moving mechanism is attached to the outer wall of the coil bobbin.

[0010] Preferably, the moving mechanism includes a connecting rod. One end of the connecting rod is provided with an upper piston, and the other end of the connecting rod is provided with a lower piston. The side of the upper piston away from the connecting rod is inserted into the inner cavity of the moving magnet through a plug rod. The lower piston is provided with a cavity, and one end of the locking mechanism is installed in the cavity opened in the lower piston.

[0011] Preferably, the locking mechanism includes a pull rod and a cam. One end of the pull rod is arranged in the cavity of the lower piston. One end of the pull rod is sleeved with a compression spring, and the compression spring is installed in the cavity of the lower piston. Oblique openings are provided at the connection between the other end of the pull rod and the cam, and the cam and the other end of the pull rod are clamped through the oblique openings.

[0012] Preferably, a centralizing ring is sleeved on the surface of the connecting rod. Through holes are provided at symmetric positions on the surface of the centralizing ring. The centralizing ring is located in the inner cavity of the sampling sleeve.

[0013] Preferably, a sampling hole is provided on one side of the surface of the upper piston, and an internal hexagonal bolt is threadedly connected to the inner cavity of the sampling hole.

[0014] Preferably, the upper piston is located in the inner cavity of the upper connecting sleeve, and the lower piston is located in the inner cavity of the sampling sleeve.

[0015] Preferably, the port of the lower connecting sleeve near the upper piston is provided with a flat top cone shape, and the end of the upper piston away from the coil skeleton is also provided with a flat top cone shape.

[0016] Preferably, the surface of the rope cap is integrally formed with tooth grooves, and the connecting cap is installed in the inner cavity of the connecting head.

[0017] Compared with the prior art, the beneficial effects of the present invention are: The present invention provides a downhole sampler for polymer flooding injection wells. The upper connecting sleeve, lower connecting sleeve and sampling sleeve in the outer shell can protect the driving assembly, locking mechanism and moving mechanism, so that the sampler can work normally when it is integrally lowered into the well, and can sample polymer solutions at different depths more than one thousand meters underground.

[0018] The present invention provides a downhole sampler for polymer flooding injection wells. By setting a circuit board to provide power, the circuit board supplies power to the coil in the actuator to generate an electromagnetic field, and the electromagnetic field drives the static magnet and the moving magnet to move downward, thereby driving the upper piston, connecting rod and lower piston in the moving mechanism to move downward to close the port at the connection between the sampling sleeve and the lower connecting head.

[0019] The present invention provides a downhole sampler for polymer flooding injection wells. Through the cooperation of the compression spring, pull rod and cam in the locking mechanism, when the lower piston moves downward, the pull rod is driven by the compression spring to be engaged with the cam, so as to lock the downward movement of the moving mechanism and avoid the rebound of the moving mechanism, thereby closing the lower port of the sampling sleeve. Description of the Drawings

[0020] Figure 1 is the overall structural schematic diagram of the present invention; Figure 2 is the cross-sectional schematic diagram of the outer shell structure of the present invention; Figure 3 is the structural schematic diagram of the outer shell, connecting head, rope cap and lower joint of the present invention; Figure 4 is the partial cross-sectional schematic diagram of the structures of the actuator, moving mechanism and locking mechanism of the present invention.

[0021] Reference numerals in the drawings: 1. Outer shell; 101. Upper connecting sleeve; 102. Lower connecting sleeve; 103. Sampling sleeve; 2. Connecting cap; 3. Connecting head; 4. Rope cap; 5. Lower joint; 6. Locking mechanism; 61. Pull rod; 62. Cam; 63. Compression spring; 7. Actuator; 71. Coil skeleton; 72. Coil; 73. Static magnet; 74. Moving magnet; 8. Moving mechanism; 81. Connecting rod; 82. Upper piston; 83. Lower piston; 9. Circuit board; 10. Centralizing ring; 11. Through hole; 12. Sampling hole; 13. Hexagon socket head cap screw. Detailed Embodiments

[0022] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] The present invention provides a downhole sampler for polymer flooding injection wells as Figures 1 to 4 shown, which includes a housing 1 and a connection cap 2. One end of the housing 1 is equipped with a connection head 3, the connection cap 2 is installed on the connection head 3, a rope cap 4 is installed on the outer side of one end of the connection head 3, the other end of the housing 1 is equipped with a lower joint 5, a locking mechanism 6 is arranged in the inner cavity at the connection between the lower joint 5 and the housing 1, an actuating mechanism 7 is arranged at one end of the inner cavity of the housing 1 close to the connection head 3, a moving mechanism 8 is arranged on the side of the actuating mechanism 7 and the locking mechanism 6 facing each other, the moving mechanism 8 is arranged in the inner cavity of the housing 1, the connection head 3 is provided with a cavity, and a circuit board 9 is installed in the cavity of the connection head 3. Similar to the conventional wire fishing process, it is lowered into the well through a blowout preventer pipe by a well testing vehicle to achieve sampling at any depth in the well. The housing 1 is connected to the connection head 3 with a rope cap 4 and lowered into the well through a wire, and an electric plate is installed inside the connection head 3 to provide power. Subsequently, the actuating mechanism 7 is installed inside the housing 1, and the actuating mechanism 7 is powered by the circuit board 9 to generate an electromagnetic field, thereby driving the moving mechanism 8 to move downward to seal and close the bottom of the housing 1. At the same time, the locking structure can lock the downward moving moving mechanism 8 to prevent the moving mechanism 8 from rebounding.

[0024] The housing 1 includes an upper connecting sleeve 101, a lower connecting sleeve 102, and a sampling sleeve 103. The upper connecting sleeve 101 is fixedly connected to the other end of the connection head 3. The two ends of the lower connecting sleeve 102 are respectively fixedly connected to one end of the upper connecting sleeve 101 and one end of the sampling sleeve 103. The other end of the sampling sleeve 103 is fixedly connected to one end of the lower joint 5. Through the upper connecting sleeve 101, the lower connecting sleeve 102, and the sampling sleeve 103 in the housing 1, the driving assembly, the locking mechanism 6, and the moving mechanism 8 can be protected, so that the sampler can work normally when it is lowered into the well as a whole, and samples of polymer solutions at different depths more than one thousand meters underground can be taken.

[0025] The actuator 7 includes a coil skeleton 71, which is installed in the inner cavity of the upper connecting sleeve 101. A coil 72 is wound on the surface of the coil skeleton 71. A static magnet 73 is installed at one end of the inner cavity of the coil skeleton 71, and a moving magnet 74 is installed at the other end of the inner cavity of the coil skeleton 71. One end of the moving mechanism 8 is in contact with the outer wall of the coil skeleton 71. Electricity is provided by setting a circuit board 9, and the circuit board 9 supplies power to the coil 72 in the actuator 7 to generate an electromagnetic field. The electromagnetic field drives the static magnet 73 and the moving magnet 74 to move downward, thereby driving the upper piston 82, the connecting rod 81 and the lower piston 83 in the moving mechanism 8 to move downward to close the bottom of the sampling sleeve 103.

[0026] The moving mechanism 8 includes a connecting rod 81, one end of which is equipped with an upper piston 82, and the other end of the connecting rod 81 is equipped with a lower piston 83. The side of the upper piston 82 away from the connecting rod 81 is inserted into the inner cavity of the moving magnet 74 through an insertion rod, and the lower piston 83 has a cavity. One end of the locking mechanism 6 is installed in the cavity formed by the lower piston 83. By setting the upper piston 82, the lower piston 83 and the connecting rod 81, the sample sampled in the sampling sleeve 103 can be sealed, so that the staff can lift the sampler to the ground and then introduce the sample into the ground test container for analysis.

[0027] The locking mechanism 6 includes a pull rod 61 and a cam 62. One end of the pull rod 61 is arranged in the cavity of the lower piston 83. One end of the pull rod 61 is sleeved with a compression spring 63. The compression spring 63 is installed in the cavity of the lower piston 83. The connection between the other end of the pull rod 61 and the cam 62 is provided with an oblique opening. The cam 62 and the other end of the pull rod 61 are clamped through the oblique opening. By setting the compression spring 63, the pull rod 61 and the cam 62 in the locking mechanism 6, when the lower piston 83 moves downward, the compression spring 63 drives the pull rod 61 and the cam 62 to clamp, so that the downward movement of the moving mechanism 8 can be locked to prevent the moving mechanism 8 from rebounding, thereby closing the port connecting the sampling sleeve 103 and the lower connector 3.

[0028] A stabilizing ring 10 is sleeved on the surface of the connecting rod 81, and a through hole 11 is opened at a symmetrical position on the surface of the stabilizing ring 10. The stabilizing ring 10 is located in the inner cavity of the sampling sleeve 103, which can provide a limiting effect on the moving rod and will not affect the polymer sampling in the sampling sleeve 103.

[0029] A sampling hole 12 is provided on one side of the surface of the upper piston 82, and the inner cavity of the sampling hole 12 is threadedly connected with a hexagon socket bolt 13. The sampler is lifted to the ground, and then the hexagon socket bolt 13 is opened, so that the sample in the sampling sleeve 103 is introduced into the ground test container through the sampling hole 12 for analysis.

[0030] The upper piston 82 is located in the inner cavity of the upper connecting sleeve 101, and the lower piston 83 is located in the inner cavity of the sampling sleeve 103, which can seal the ports of the sampling sleeve 103 and the lower connecting sleeve 102.

[0031] The port of the lower connecting sleeve 102 near the upper piston 82 is arranged in a flat-top cone shape, and the end of the upper piston 82 away from the coil skeleton 71 is also arranged in a flat-top cone shape, which enhances the sealing performance between the upper piston 82 and the port of the lower connecting sleeve 102 and prevents the polymer in the sampling sleeve 103 from leaking.

[0032] The surface of the rope cap 4 is integrally formed with tooth grooves, and the connecting cap 2 is installed in the inner cavity of the connecting head 3, which facilitates the staff to wind the steel wire around the rope cap 4 and prevents it from falling off easily.

[0033] During specific use, first, the staff winds the steel wire around the rope cap 4 of the sampler through the conventional method, and then the well testing vehicle lowers it into the well through the blowout preventer pipe to achieve sampling at any depth underground. When the sampler contacts the polymer in the well, the polymer enters the sampling sleeve 103 through the port at the lower end of the sampling sleeve 103. Then, power is supplied to the coil 72 in the actuator 7 through the circuit board 9 to generate an electromagnetic field. The electromagnetic field drives the static magnet 73 and the moving magnet 74 to move downward, thereby driving the upper piston 82, the connecting rod 81, and the lower piston 83 in the moving mechanism 8 to move downward, so that the upper piston 82 seals the port of the lower connecting sleeve 102, and the lower piston 83 seals the port of the lower joint 5. During the sealing process of the lower piston 83, the lower piston 83 squeezes the compression spring 63 and then pushes the pull rod 61, so that the pull rod 61 is clamped and fixed with the cam 62, making the moving mechanism 8 locked. The locking mechanism 6 prevents the upper piston 82 and the lower piston 83 from accidentally opening during the process of lifting the instrument, so that the polymer sampled in the sampling sleeve 103 can be collected. Subsequently, the sampler is lifted to the ground. After the instrument is taken to the ground, the inner hexagon bolt 13 is opened, and the sample is introduced into the ground test container for analysis and testing.

[0034] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A downhole sampler for polymer flooding injection wells, comprising a housing (1) and a connecting cap (2), characterized in that: One end of the said outer shell (1) is equipped with a connector (3), the connection cap (2) is installed on the connector (3), a rope cap (4) is installed on the outer side of one end of the connector (3), the other end of the outer shell (1) is installed with a lower joint (5), a locking mechanism (6) is arranged in the inner cavity at the connection between the lower joint (5) and the outer shell (1), an actuating mechanism (7) is arranged at one end of the inner cavity of the outer shell (1) close to the connector (3), a moving mechanism (8) is arranged on the side facing each other between the actuating mechanism (7) and the locking mechanism (6), the moving mechanism (8) is arranged in the inner cavity of the outer shell (1), the connector (3) is provided with a cavity, and a circuit board (9) is installed in the cavity of the connector (3).

2. The downhole sampler for polymer flooding injection wells according to claim 1, characterized in that: The said outer shell (1) includes an upper connecting sleeve (101), a lower connecting sleeve (102) and a sampling sleeve (103), the upper connecting sleeve (101) is fixedly connected to the other end of the connector (3), both ends of the lower connecting sleeve (102) are fixedly connected to one end of the upper connecting sleeve (101) and the sampling sleeve (103) respectively, and the other end of the sampling sleeve (103) is fixedly connected to one end of the lower joint (5).

3. A downhole sampler for polymer flooding injection wells according to claim 2, characterized in that: The said actuating mechanism (7) includes a coil bobbin (71), the coil bobbin (71) is installed in the inner cavity of the upper connecting sleeve (101), a coil (72) is wound on the surface of the coil bobbin (71), a static magnet (73) is installed at one end of the inner cavity of the coil bobbin (71), a moving magnet (74) is installed at the other end of the inner cavity of the coil bobbin (71), and one end of the moving mechanism (8) is in contact with the outer wall of the coil bobbin (71).

4. The downhole sampler for polymer flooding injection well according to claim 3, characterized in that: The said moving mechanism (8) includes a connecting rod (81), an upper piston (82) is installed at one end of the connecting rod (81), a lower piston (83) is installed at the other end of the connecting rod (81), the side of the upper piston (82) away from the connecting rod (81) is inserted into the inner cavity of the moving magnet (74) through an insertion rod, the lower piston (83) is provided with a cavity, and one end of the locking mechanism (6) is installed in the cavity opened in the lower piston (83).

5. The downhole sampler for polymer flooding injection well according to claim 4, characterized in that: The said locking mechanism (6) includes a pull rod (61) and a cam (62), one end of the pull rod (61) is arranged in the cavity of the lower piston (83), a compression spring (63) is sleeved on one end of the pull rod (61), the compression spring (63) is installed in the cavity of the lower piston (83), and inclined openings are provided at the connection between the other end of the pull rod (61) and the cam (62), and the cam (62) and the other end of the pull rod (61) are clamped through the inclined openings.

6. The downhole sampler for polymer flooding injection well according to claim 5, wherein: A centering ring (10) is sleeved on the surface of the connecting rod (81), through holes (11) are provided at symmetric positions on the surface of the centering ring (10), and the centering ring (10) is located in the inner cavity of the sampling sleeve (103).

7. A downhole sampler for polymer flooding injection wells according to claim 4, characterized in that: Sampling holes (12) are provided on one side of the surface of the upper piston (82), and hexagon socket head cap screws (13) are threadedly connected in the inner cavities of the sampling holes (12).

8. A downhole sampler for polymer flooding injection wells according to claim 7, characterized in that: The upper piston (82) is located in the inner cavity of the upper connecting sleeve (101), and the lower piston (83) is located in the inner cavity of the sampling sleeve (103).

9. The downhole sampler for polymer flooding injection wells according to claim 3, wherein: The port of the lower connecting sleeve (102) close to the upper piston (82) is provided with a flat top cone shape, and one end of the upper piston (82) far from the coil bobbin (71) is also provided with a flat top cone shape.

10. A downhole sampler for polymer flooding injection wells according to claim 1, characterized in that: The surface of the rope cap (4) is integrally formed with tooth grooves, and the connecting cap (2) is installed in the inner cavity of the connecting head (3).

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