Sectional seal whole cylinder type oil pumping unit

Abstract

This invention relates to a segmented, sealed, integral-tube oil pump, belonging to the technical field of oilfield mechanical oil production equipment. The invention includes an outer pump barrel, with a threaded sealing connection at the top to an upper connector, and a lower part connected to a connecting cylinder. The connecting cylinder is threadedly connected to a fixed valve assembly, and the lower part of the fixed valve assembly is connected to a lower connector. The bottom diameter of the inner tube of the outer pump barrel is smaller than its top diameter, and a boss ring is provided on the middle end ring. The grooved ring of the bottom sealing sleeve is embedded in the boss ring. After the inner ring of the sealing sleeve is bored and ground, it achieves a clearance fit with the plunger to achieve sealed oil pumping. The convex ring of the top sealing sleeve is embedded in the groove of the pressure sleeve, which is threadedly connected to the upper connector. Rotating the pressure sleeve locks the sealing sleeve. This structure adapts to the bending conditions of the pump barrel, avoids uneven wear, and ensures sealing performance and stable and efficient oil pumping.

Description

Technical Field

[0001] This invention relates to the field of oilfield mechanical oil production equipment technology, specifically a segmented sealed cylindrical oil pump. Background Technology

[0002] Traditional monolithic oil pumps have a rigid, one-piece pump barrel, which has obvious structural defects in actual downhole operations and is difficult to adapt to the complex downhole stress environment.

[0003] Traditional solid-tube oil pumps are prone to hard bending deformation during handling, transportation, and unloading. Furthermore, during long-term service, the plunger is constantly in a state of high-frequency reciprocating motion, and the pump barrel is continuously subjected to combined loads such as plunger reciprocating friction and fluid impact, gradually leading to irreversible plastic bending deformation. Once the pump barrel bends, it directly disrupts the designed fit clearance between it and the plunger, causing localized contact wear. This problem not only drastically accelerates the wear and failure process of the pump barrel and plunger but also significantly reduces the sealing performance of the pump-pump pair, resulting in serious leakage during oil pumping operations.

[0004] Traditional solid-tube oil pumps have a long inner tube, requiring complex straightening after machining. The machining process includes surface treatments such as nickel-phosphorus plating and carburizing, followed by precision machining of the inner hole using a long-stroke honing machine to ensure accuracy and surface roughness. This complexity and high equipment requirements result in long production cycles and high manufacturing costs.

[0005] Currently, the industry can only address these issues by using higher-strength pump barrel materials and improving the machining precision of the pump barrel. While these methods can delay pump barrel bending to some extent, they cannot fundamentally solve the problem of pump barrel bending caused by transportation and long-term operation, nor can they eliminate the subsequent effects such as uneven wear and seal failure caused by pump barrel bending. This makes it difficult to meet the needs of efficient and stable oilfield pumping operations. Therefore, there is an urgent need to develop an oil pump structure that can adapt to pump barrel bending conditions and avoid uneven wear and seal failure, thus overcoming the technical shortcomings of traditional solid-tube oil pumps. Summary of the Invention

[0006] To address the technical problem that traditional solid-tube oil pumps are prone to bending under external forces and long-term operation, leading to uneven wear between the pump barrel and plunger, poor sealing performance, and reduced oil pumping efficiency, this invention provides a segmented-seal solid-tube oil pump. Through a segmented sealing sleeve structure design, combined with a compression buffer component, external forces are effectively offset. At the same time, it adapts to the slight bending deformation of the plunger, avoiding uneven wear, ensuring the sealing effect between the pump barrel and plunger, and maintaining a stable oil pumping efficiency.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A segmented sealed cylindrical oil pump is provided, including an outer pump barrel 4. The top of the outer pump barrel 4 is connected to an upper connector 9 via a threaded seal, and the upper connector 9 is connected to the downhole tubing. The bottom diameter of the inner tube of the outer pump barrel 4 is smaller than the top diameter, and an end ring is formed in the middle. The end ring is provided with a boss ring 401, which is embedded in the groove ring of the bottommost group of N sealing sleeves 6.

[0009] The main body of the sealing sleeve 6 is an inner liner 601. The upper end face of the inner liner is provided with a convex ring, and the lower end face is machined with a grooved ring. A pressure-bearing sealing ring 603 is installed inside the grooved ring. N sealing sleeves 6 are connected in series through the convex ring and the grooved ring. The outer ring of the inner liner 601 is provided with a concave ring, and a buffer ring 602 made of compression buffer material is fitted on the concave ring. After the inner ring of the inner liner 601 is machined and bored, it is clearance-fitted with the plunger 5. The clearance value is 0.02mm-0.07mm, and the oil pumping operation is completed by sliding seal.

[0010] The topmost group of the N sealing sleeves 6 has a convex ring embedded in the grooved ring of the pressure sleeve 8. The external thread of the pressure sleeve 8 is connected to the internal thread of the upper connector 9. A sealing ring 7 is fitted between the mating surfaces of the pressure sleeve 8 and the upper connector 9. By rotating the pressure sleeve 8 to press the pressure-bearing sealing ring 603, the N sealing sleeves 6 are locked as a whole.

[0011] The buffer ring 602 is made of either soft plastic polyurethane or butyl rubber putty.

[0012] The length of the inner liner 601 is 40mm-100mm.

[0013] The number of sealing sleeves 6 is N, and the number is designed according to the requirements. N is an integer greater than or equal to 4 and less than or equal to 20.

[0014] After the convex ring and grooved ring between the sealing sleeves 6 are assembled and nested, an adaptation gap is designed for the convex ring and grooved ring to cooperate. This gap can realize the adaptive adjustment of the friction gap between the sealing sleeve 6 and the plunger 5.

[0015] A plunger 5 is inserted inside the outer pump cylinder 4. A pull rod 10 is connected to the upper part of the plunger 5. The length of the plunger 5 is greater than that of the outer pump cylinder 4 to ensure that the inner rings of the N sealing sleeves 6 always maintain a cooperative state with the plunger 5 during the oil pumping operation.

[0016] The lower part of the outer pump cylinder 4 is connected to the connecting cylinder 3. The connecting cylinder 3 is connected to the fixed valve group 2 by a thread. The fixed valve group 2 is equipped with a fixed valve. The lower part of the fixed valve group 2 is connected to the lower connector 1. The lower part of the lower connector 1 is connected to the gas-liquid-sand separator by a thread.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention effectively solves the problem of traditional solid-tube oil pumps being easily bent by external forces. The compression buffer ring on the outside of the sealing sleeve can directly offset the action of external forces downhole, preventing the core sealing part of the pump barrel from bending along with the outer pump barrel, thus avoiding a series of failures caused by the bending of the pump barrel from the root.

[0019] The segmented inner bushing, combined with the reserved clearance design, allows for slight deflection of the inner bushing, which can accommodate the minor bending deformation of the plunger. This ensures that the fit clearance between the inner bushing and the plunger is always uniform, completely eliminating uneven wear and extending the service life of both the plunger and the inner bushing.

[0020] This invention employs a segmented sealing sleeve structure, with an inner sleeve length of only 40mm-100mm, significantly reducing the processing difficulty compared to the long inner cylinder of traditional monolithic oil pumps. After surface treatments such as nickel-phosphorus plating and carburizing, there is no need to use a long-stroke honing machine; ordinary processing equipment can complete the inner hole boring and finishing. Furthermore, the short-size structure eliminates the need for complex straightening processes, effectively simplifying the processing technology, shortening the production cycle, and reducing manufacturing costs and equipment investment barriers. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 A schematic diagram of a segmented, sealed, cylindrical oil pump structure;

[0023] Figure 2 A schematic diagram of a segmented, sealed, cylindrical oil pump sealing sleeve;

[0024] Figure 3 This is a partial schematic diagram of a segmented, sealed, cylindrical oil pump.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Lower connector; 2. Fixed valve assembly; 3. Connecting cylinder; 4. Outer pump cylinder; 401. Boss ring; 5. Plunger; 6. Sealing sleeve; 601. Inner liner; 602. Buffer ring; 603. Pressure-bearing sealing ring; 7. Sealing ring; 8. Pressure sleeve; 9. Upper connector; 10. Pull rod. Detailed Implementation

[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Example

[0030] like Figures 1 to 3 As shown, a segmented sealed cylindrical oil pump includes an outer pump barrel 4. The top of the outer pump barrel 4 is connected to an upper connector 9 via a threaded seal, and the upper connector 9 is connected to the downhole tubing. The bottom diameter of the inner tube of the outer pump barrel 4 is smaller than the top diameter, and an end ring is formed in the middle. The end ring is provided with a boss ring 401, which is embedded in the groove ring of the bottommost group of N sealing sleeves 6.

[0031] The main body of the sealing sleeve 6 is an inner liner 601. The upper end face of the inner liner is provided with a convex ring, and the lower end face is machined with a grooved ring. A pressure-bearing sealing ring 603 is installed inside the grooved ring. N sealing sleeves 6 are connected in series through the convex ring and the grooved ring. The outer ring of the inner liner 601 is provided with a concave ring, and a buffer ring 602 made of compression buffer material is fitted on the concave ring. After the inner ring of the inner liner 601 is machined and bored, it is clearance-fitted with the plunger 5. The clearance value is 0.02mm-0.07mm. The oil pumping operation is completed by sliding seal.

[0032] The topmost group of the N sealing sleeves 6 has a convex ring embedded in the grooved ring of the pressure sleeve 8. The external thread of the pressure sleeve 8 is connected to the internal thread of the upper connector 9. A sealing ring 7 is fitted between the mating surfaces of the pressure sleeve 8 and the upper connector 9. By rotating the pressure sleeve 8 to press the pressure-bearing sealing ring 603, the N sealing sleeves 6 are locked as a whole.

[0033] After the convex ring and grooved ring between the sealing sleeves 6 are assembled and nested, an adaptation gap is designed for the convex ring and grooved ring to cooperate. This gap can realize the adaptive adjustment of the friction gap between the sealing sleeve 6 and the plunger 5.

[0034] A plunger 5 is inserted inside the outer pump cylinder 4. A pull rod 10 is connected to the upper part of the plunger 5. The length of the plunger 5 is greater than that of the outer pump cylinder 4 to ensure that the inner rings of the N sealing sleeves 6 always maintain a cooperative state with the plunger 5 during the oil pumping operation.

[0035] The lower part of the outer pump cylinder 4 is connected to the connecting cylinder 3. The connecting cylinder 3 is connected to the fixed valve group 2 by a thread. The fixed valve group 2 is equipped with a fixed valve. The lower part of the fixed valve group 2 is connected to the lower connector 1. The lower part of the lower connector 1 is connected to the gas-liquid-sand separator by a thread.

[0036] The buffer ring 602 is made of either soft plastic polyurethane or butyl rubber putty.

[0037] The length of the inner liner 601 is 40mm-100mm.

[0038] The number of sealing sleeves 6 is N, and the number is designed according to the requirements. N is an integer greater than or equal to 4 and less than or equal to 20.

[0039] The working principle of a segmented sealed cylindrical oil pump is:

[0040] When this oil pump is run into the well, the upper connector 9 is fixedly connected to the downhole tubing, and the lower connector 1 is connected to the gas-liquid-sand separator. The sucker rod string drives the tie rod 10 and the plunger 5 to perform reciprocating oil pumping motion in the sealing sleeve 6 inside the outer pump barrel 4. During the upstroke, the fixed valve opens, and the crude oil processed by the gas-liquid-sand separator enters the pump chamber. During the downstroke, the fixed valve closes, and the crude oil is lifted to the surface with the movement of the plunger 5. When the outer pump barrel 4 bends under external force, or the plunger 5 undergoes slight bending deformation, the compression buffer ring 602 on the outer side of the inner bushing 601 will undergo compression deformation to offset the squeezing effect of the external force and prevent the inner bushing 601 from undergoing hard bending synchronously with the outer pump barrel 4. At the same time, the gap reserved between the convex ring and the grooved ring allows the segmented inner bushing 601 to deflect and adapt slightly according to the bending state of the plunger 5, ensuring that the inner ring of each inner bushing 601 maintains a uniform fit clearance with the plunger 5 and that no local uneven wear occurs. The pressure-bearing sealing ring 603 can seal the connection gap between adjacent inner bushings 601, effectively preventing the fluid in the pump barrel from flowing out of the gap and ensuring the sealing and stability of the oil pumping operation.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A segmented sealed cylindrical oil pump, characterized in that, Includes an outer pump cylinder (4), the top of which is connected to a joint (9) by a threaded seal. The bottom diameter of the inner tube of the outer pump cylinder (4) is smaller than the top diameter, and an end ring is formed in the middle. A boss ring (401) is provided on the end ring. The boss ring (401) is embedded in the groove ring of the bottom group among N sealing sleeves (6). The main body of the sealing sleeve (6) is an inner sleeve (601). The upper end face of the inner sleeve is provided with a convex ring, and the lower end face is machined with a grooved ring. The grooved ring is filled with a pressure-bearing sealing ring (603). N sealing sleeves (6) are connected in series through the convex ring and the grooved ring. The outer ring of the inner sleeve (601) is provided with a concave ring. The concave ring is fitted with a buffer ring (602) made of compression buffer material. After the inner ring of the inner sleeve (601) is machined and bored, it is clearance-fitted with the plunger (5). The clearance value is 0.02mm-0.07mm. The topmost group of the N sealing sleeves (6) has a convex ring embedded in the grooved ring of the pressure sleeve (8). The external thread of the pressure sleeve (8) is connected to the internal thread of the upper connector (9). A sealing ring (7) is fitted between the mating surfaces of the pressure sleeve (8) and the upper connector (9). By rotating the pressure sleeve (8) to press the pressure-bearing sealing ring (603), the N sealing sleeves (6) are locked as a whole. After the convex ring and grooved ring between the sealing sleeves (6) are assembled and nested, an adaptation gap is designed for the convex ring and grooved ring to cooperate. This gap can realize the adaptive adjustment of the friction gap between the sealing sleeve (6) and the plunger (5). When the outer pump cylinder (4) is bent by external force, or when the plunger (5) undergoes slight bending deformation, the compression buffer ring (602) on the outside of the inner bushing (601) will undergo compression deformation to offset the squeezing effect brought by the external force and prevent the inner bushing (601) from undergoing hard bending synchronously with the outer pump cylinder (4).

2. The segmented sealed integral cylinder oil pump according to claim 1, characterized in that, The outer pump barrel (4) is fitted with a plunger (5), and the upper part of the plunger (5) is connected to a pull rod (10). The length of the plunger (5) is greater than that of the outer pump barrel (4) to ensure that the inner ring of the N sealing sleeves (6) always maintains a cooperative state with the plunger (5) during the oil pumping operation.

3. A segmented sealed integral cylinder oil pump according to claim 1, characterized in that, The lower part of the outer pump cylinder (4) is connected to the connecting cylinder (3), and the connecting cylinder (3) is connected to the fixed valve group (2) by a thread. The fixed valve group (2) is equipped with a fixed valve inside; the lower part of the fixed valve group (2) is connected to the lower connector (1).

4. A segmented sealed integral cylinder oil pump according to claim 1, characterized in that, The buffer ring (602) is made of either soft plastic polyurethane or butyl rubber putty.

5. A segmented sealed integral cylinder oil pump according to claim 1, characterized in that, The length of the inner liner (601) is 40mm-100mm.

6. A segmented sealed integral cylinder oil pump according to claim 1, characterized in that, The number of sealing sleeves (6) is N, and the number is designed according to the requirements. N is an integer greater than or equal to 4 and less than or equal to 20.

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