Hydraulic cylinder of oil pumping unit and using method

Abstract

The invention provides a hydraulic cylinder of an oil pumping unit and a using method, the hydraulic cylinder comprises an outer cylinder barrel and an inner cylinder barrel which are coaxially arranged in a sleeved mode, and the inner cylinder barrel is hollow and allows a sucker rod to penetrate through; a slidable pushing barrel is arranged between the outer cylinder barrel and the inner cylinder barrel, and one end of the pushing barrel extends out and is connected with a sucker rod. The pushing barrel is hydraulically driven to reciprocate between the inner cylinder barrel and the outer cylinder barrel, and the sucker rod is indirectly driven to move up and down for oil pumping operation. According to the structure, the sucker rod is limited in the inner cylinder barrel to operate, pollutants such as underground crude oil and gravel are prevented from making contact with a hydraulic sealing component, and the service life is remarkably prolonged; meanwhile, a traditional long piston rod is omitted, the structure is compact, weight is light, and a platform is not needed. The hydraulic system adopts electro-hydraulic proportional variable control, stepless adjustment of the stroke frequency is achieved, operation is stable, efficiency and energy saving are achieved, and throttling loss is avoided. In addition, an exhaust hole, a silencer and a spacing sleeve are arranged, so that responsiveness, noise reduction and reliability are further improved. The device is suitable for various oil field wellheads, and is especially suitable for intelligent and high-reliability oil pumping operation scenes.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of oil and gas exploitation equipment, in particular to a hydraulic cylinder of a pumping unit and a use method. BACKGROUND

[0002] In the field of oil exploitation, the pumping unit is the core ground equipment for realizing rod pump oil production. At present, although the widely used beam-type pumping unit has simple structure and reliable operation, it has inherent defects such as high energy consumption, low system efficiency, dependence on manual adjustment of stroke and stroke, and difficulty in realizing intelligent control. Especially in the working condition of low-yield wells or heavy oil wells, the energy efficiency problem is more prominent.

[0003] In order to improve the energy efficiency and automation level, in recent years, hydraulic pumping units have gradually attracted attention. The conventional hydraulic pumping unit usually adopts a single-cylinder structure, and the piston rod is directly driven by the hydraulic cylinder, and the piston rod is connected with the wellhead sucker rod to realize the reciprocating pumping action. However, in actual application, such structure faces severe challenges: Because the pumping operation needs a long stroke, the piston rod of the hydraulic cylinder must be lengthened and needs to extend into the production tree and even partially into the wellbore. In this process, the piston rod is exposed to the wellhead environment for a long time, and is easily eroded by crude oil, sand, corrosive gas and moisture, resulting in surface wear and corrosion, and further damaging the sealing performance; at the same time, the piston rod will bring the pollutants such as crude oil and sand particles in the wellhead into the inside of the hydraulic cylinder during reciprocating motion, causing pollution of hydraulic oil, blockage of valve parts and accelerated failure of sealing components, seriously affecting the service life and operation reliability of the equipment.

[0004] Therefore, it is urgent to provide a hydraulic cylinder of a pumping unit which can realize reliable driving of long stroke under the premise of avoiding pollution of the hydraulic system and prolonging the service life of the seal, and has comprehensive advantages such as high efficiency, energy saving, intelligent control, compact structure and strong environmental adaptability, so as to overcome the above-mentioned defects of the prior art. SUMMARY

[0005] The main purpose of the present application is to provide a hydraulic cylinder of a pumping unit and a use method, which solves the problems in the background art.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a hydraulic oil cylinder coaxially installed above a production tree, the hydraulic oil cylinder being used to drive the up-down reciprocating movement of a sucker rod in the center of the production tree for pumping operation; A coaxial inner cylinder is fixedly arranged in the outer cylinder barrel of the hydraulic oil cylinder, the inner cylinder is hollow, and the sucker rod penetrates through the inner cylinder and is arranged coaxially with the inner cylinder; A sliding push cylinder is arranged between the outer cylinder barrel and the inner cylinder, the end of the push cylinder extends out of the outer cylinder barrel, and the push cylinder is connected with the sucker rod.

[0007] Preferably, the bottom of the hydraulic cylinder is connected with the Christmas tree through a support frame, and the sucker rod in the hydraulic cylinder is connected with the sucker rod on the Christmas tree through a sucker rod coupling.

[0008] Preferably, the tail of the outer cylinder is provided with a mounting seat, and the tail of the inner cylinder is provided with a positioning ring outside the tail of the inner cylinder, and the positioning ring is fixedly connected with the mounting seat and the outer cylinder through flange bolts. The end of the mounting seat is also provided with a connecting flange, and the connecting flange is fixedly connected with the support frame on the Christmas tree through flange bolts.

[0009] Preferably, the first piston is fixedly arranged at one end of the push cylinder, and the end cover is fixedly arranged at the other end of the push cylinder, and the inner and outer sides of the first piston are respectively abutted on the outer cylinder and the inner cylinder through sealing assemblies, The sucker rod penetrates the end cover, and the end cover is provided with a sucker rod clamp at the end of the end cover, and the sucker rod clamp is used to fix the sucker rod on the end cover.

[0010] Preferably, the end of the outer cylinder is provided with a cylinder cover, and the inner side of the cylinder cover is abutted on the outer side of the push cylinder through a sealing assembly. The end of the inner cylinder is provided with a second piston, and the outer side of the second piston is abutted on the inner side of the push cylinder through a sealing assembly.

[0011] Preferably, the second piston is provided with a plurality of radial exhaust holes on the circumferential side, and the exhaust holes are communicated with the cavity formed between the push cylinder and the inner cylinder.

[0012] Preferably, the first piston moves in the cavity formed between the push cylinder and the inner cylinder, and the cavity is divided into a rod cavity and a rodless cavity, and the outer cylinder is provided with radial oil holes on both sides, and the oil holes on both sides are respectively communicated with the rod cavity and the rodless cavity.

[0013] Preferably, the end cover is provided with a radial through hole on the circumferential side, the through hole is communicated with the inner cavity of the inner cylinder, and a silencer is installed on the through hole.

[0014] Preferably, a spacer sleeve is arranged on the outer side of the push cylinder, the spacer sleeve is arranged in the rod cavity, and the spacer sleeve is used to abut between the first piston and the cylinder cover.

[0015] A method for using a hydraulic cylinder of an oil pumping machine, and the method steps are as follows: S1, the hydraulic cylinder is installed above the Christmas tree at the wellhead through a support frame and is coaxially arranged with the Christmas tree, and the sucker rod in the hydraulic cylinder is connected with the sucker rod in the Christmas tree through a sucker rod coupling; S2, the sucker rod in the hydraulic cylinder penetrates the inner cylinder and the end cover, and is fixed through the bolts on the sucker rod clamp at the end of the end cover; S3, the hydraulic cylinder is connected with the hydraulic pump station through a high-pressure oil pipe, and the push cylinder in the hydraulic cylinder is controlled to move up and down reciprocatingly through an electric control system, thereby driving the sucker rod to drive the oil pumping pump to perform oil pumping operation.

[0016] This invention provides a hydraulic cylinder for an oil pumping unit and its usage method, with the following advantages: 1. By adopting a three-layer coaxial casing structure consisting of an outer cylinder, an inner cylinder, and a pusher cylinder, the sucker rod, which is susceptible to corrosion from downhole crude oil, sand, and other contaminants, is restricted to move within the inner cylinder. Meanwhile, the pusher cylinder and sealing components are completely enclosed within a clean hydraulic chamber, preventing external contaminants from entering the hydraulic system. This significantly extends the service life of the seals and the overall hydraulic cylinder, and improves operational reliability.

[0017] 2. Traditional hydraulic cylinders require a long piston rod to extend into the wellhead, which is prone to corrosion and wear. This solution indirectly drives the sucker rod by sliding the pusher between the inner and outer cylinders, without having to extend it downhole. This satisfies the long stroke requirement of the sucker rod while maintaining the overall compact structure, small size, and light weight of the hydraulic cylinder, making it easy to install and eliminating the need for a special platform.

[0018] 3. By adopting electro-hydraulic proportional variable technology, stepless adjustment of stroke rate and precise control of up and down speed are achieved. The system has no energy loss due to throttling speed regulation, achieving the best match between load, speed and power. Compared with traditional beam pumping units, it significantly reduces energy consumption, improves energy efficiency, and supports intelligent operation. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Fig. 1 This is a schematic diagram of the overall structure and installation of the present invention; Fig. 2 This is a front sectional view of the hydraulic cylinder of the present invention; Fig. 3 This is a schematic diagram of the extension of the pusher cylinder of the present invention; In the diagram: 1. Support casing; 2. Tree trunk; 3. Support frame; 4. Hydraulic cylinder; 401. Outer cylinder; 402. Mounting seat; 403. Connecting flange; 404. Positioning ring; 405. First piston; 406. Spacer sleeve; 407. Inner cylinder; 408. Second piston; 409. Cylinder head; 410. End cover; 411. Silencer; 412. Exhaust port; 413. Push cylinder; 5. Sucker rod; 6. Sucker rod coupling; 7. Sucker rod clamp. Detailed Implementation

[0020] Example 1 like Figs. 1-3 As shown, a hydraulic cylinder for an oil pumping unit includes a hydraulic cylinder 4 coaxially mounted above the tree 2. The hydraulic cylinder 4 is used to drive the sucker rod 5 at the center of the tree 2 to move up and down reciprocally to perform oil pumping operations. The outer cylinder 401 of the hydraulic cylinder 4 is fixedly equipped with a coaxial inner cylinder 407. The inner cylinder 407 is hollow inside, and the sucker rod 5 passes through the inner cylinder 407 and is coaxial with it. A pushing cylinder 413 is arranged between the outer cylinder 401 and the inner cylinder 407 to slide, and the end of the pushing cylinder 413 extends outside the outer cylinder 401 and is connected with the sucker rod 5.

[0021] The conventional beam-type pumping unit has problems of high energy consumption, low efficiency and dependence on manual adjustment, and the hydraulic pumping unit has advantages of energy efficiency, intelligence and environmental adaptability. The hydraulic cylinder in the conventional hydraulic pumping unit is composed of a cylinder barrel, a piston rod and a piston. When the hydraulic pumping unit is applied to the long stroke of the sucker rod 5 of the pumping unit, the corresponding piston rod has a long moving stroke. When the production tree 2 is installed at the wellhead, the piston rod needs to extend into the production tree 2 and enter the wellhead. Long-time operation will cause the external corrosion and wear of the piston rod. The piston rod will also carry crude oil or sand and stone foreign matters into the hydraulic cylinder, which will also affect the service life of the sealing assembly of the hydraulic cylinder.

[0022] In this example, the outer cylinder 401 and the inner cylinder 407 in the hydraulic cylinder 4 are coaxial sleeve structures, the pushing cylinder 413 is arranged between the outer cylinder 401 and the inner cylinder 407 to slide, the sucker rod 5 penetrates the hollow inner cylinder 407 and is connected with the end of the pushing cylinder 413, so that the pushing cylinder 413 drives the sucker rod 5 to move up and down to perform oil pumping operation. The sucker rod 5 moves in the inner cylinder 407, only the sucker rod 5 enters the production tree 2 and the wellhead, the pushing cylinder 413 is not polluted with the sealing assembly, and the service life of the pushing cylinder 413 is guaranteed. The hydraulic cylinder 4 is automatically controlled by electro-hydraulic integration. The hydraulic system adopts electro-hydraulic proportional variable technology to control the up and down running speed of the cylinder, and the stroke is steplessly adjustable. The system has no throttling speed regulation energy loss, realizes the best matching of load, running speed and driving power, and runs and changes direction stably and reliably. The hydraulic cylinder 4 has the advantages of compact structure, small size, light weight, small floor area, and is suitable for various scenes and does not need to be installed on a platform.

[0023] Preferably, the bottom of the hydraulic cylinder 4 is connected with the production tree 2 through the support frame 3, and the sucker rod 5 in the hydraulic cylinder 4 is connected with the sucker rod 5 on the production tree 2 through the sucker rod 5 coupling.

[0024] The hydraulic cylinder 4 is coaxially connected with the production tree 2 through the support frame 3, and the sucker rod 5 is coaxially connected through the sucker rod 5 coupling. The hydraulic cylinder 4 drives the sucker rod 5 and the sucker rod 5 coupling to move into the inner cylinder 407.

[0025] Preferably, the tail of the outer cylinder 401 is provided with a mounting seat 402, and the tail of the inner cylinder 407 is externally provided with a positioning ring 404. The positioning ring 404 is fixedly connected with the mounting seat 402 and the outer cylinder 401 through flange bolts. The end of the mounting seat 402 is also provided with a connecting flange 403, and the connecting flange 403 is fixedly connected with the support frame 3 on the production tree 2 through flange bolts.

[0026] The positioning ring 404 is welded and fixed outside the end of the inner cylinder 407, and is fixedly connected with the mounting seat 402 and the outer cylinder 401 through bolts, so as to ensure that the outer cylinder 401 and the inner cylinder 407 are coaxially arranged.

[0027] Preferably, the pushing cylinder 413 is fixedly provided with the first piston 405 at one end and the end cover 410 at the other end, and the inner and outer sides of the first piston 405 are respectively abutted on the outer cylinder 401 and the inner cylinder 407 through sealing assemblies and slide, The sucker rod 5 penetrates through the end cover 410, and the end cover 410 is provided with a sucker rod 5 clamp at the end, which is used for fixing the sucker rod 5 on the end cover 410.

[0028] The hydraulic pump station passes hydraulic oil into the outer cylinder 401 through a hydraulic oil pipe, so as to drive the first piston 405 to move, and then the sucker rod 5 reciprocatingly moves through the pushing cylinder 413 to realize oil pumping operation, and the sucker rod 5 clamp is locked and clamped on the sucker rod 5 through bolts, so as to realize connection and fixation.

[0029] Preferably, the outer cylinder 401 is fixedly provided with the cylinder cover 409 at the end, and the inner side of the cylinder cover 409 is abutted on the outer side of the pushing cylinder 413 through a sealing assembly. The second piston 408 is fixedly provided at the end of the inner cylinder 407, and the outer side of the second piston 408 is abutted on the inner side of the pushing cylinder 413 through a sealing assembly.

[0030] The end of the pushing cylinder 413 can be telescoped outside the outer cylinder 401 through the sealing assembly on the outer side of the second piston 408 and the sealing assembly on the inner side of the cylinder cover 409.

[0031] Preferably, the second piston 408 is provided with a plurality of radial exhaust holes 412 penetrating the periphery, and the exhaust holes 412 are communicated with the cavity formed between the pushing cylinder 413 and the inner cylinder 407.

[0032] The cavity formed between the pushing cylinder 413 and the inner cylinder 407 is compressed during the movement of the first piston 405, and the air in the cavity is exhausted through the exhaust holes 412 on the periphery of the second piston 408.

[0033] Preferably, the first piston 405 moves in the cavity formed between the pushing cylinder 413 and the inner cylinder 407, so as to divide the cavity into a rod cavity and a rodless cavity, and the outer cylinder 401 is provided with radial oil holes penetrating the two sides, and the oil holes on the two sides are respectively communicated with the rod cavity and the rodless cavity.

[0034] Preferably, the end cover 410 is provided with a radial through hole penetrating the periphery, the through hole is communicated with the inner cavity of the inner cylinder 407, and the through hole is provided with a silencer 411.

[0035] The telescoping of the pushing cylinder 413 compresses the air in the inner cylinder 407, which requires air exhaust and air intake, and the noise of the air exhaust and air intake can be eliminated by the muffler 411.

[0036] Preferably, the pushing cylinder 413 is sleeved with a spacer sleeve 406, which is located in the rod cavity and used to abut between the first piston 405 and the cylinder head 409.

[0037] When the first piston 405 slides to the right to push, the spacer sleeve 406 can abut between the first piston 405 and the cylinder head 409, leaving a gap therebetween, so that there is enough space for the hydraulic oil to pass into the hydraulic oil cylinder 4, so that the hydraulic oil cylinder 4 can respond quickly.

[0038] Embodiment 2 As Figs. 1-3 shown, further illustrated in combination with Embodiment 1, a method for using a hydraulic cylinder of a pumping unit, the method steps are as follows: S1, the hydraulic oil cylinder 4 is installed above the Christmas tree 2 at the wellhead through the support frame 3, and is coaxially arranged with the Christmas tree 2, and the sucker rod 5 in the Christmas tree 2 is butt jointed with the sucker rod 5 in the hydraulic oil cylinder 4 through the sucker rod 5 coupling; S2, the sucker rod 5 in the hydraulic oil cylinder 4 penetrates the inner cylinder 407 and the end cover 410, and is fixed by the bolts on the sucker rod 5 clamp on the end cover 410; S3, the hydraulic oil cylinder 4 is connected with the hydraulic pump station through the high-pressure oil pipe, and the pushing cylinder 413 in the hydraulic oil cylinder 4 is controlled to move up and down reciprocatingly through the electric control system, thereby driving the sucker rod 5 to drive the oil pumping pump to perform oil pumping operation.

[0039] The hydraulic oil is passed into the hydraulic oil cylinder 4 by the hydraulic pump station through the electric control system, thereby controlling the pushing cylinder 413 to move up and down reciprocatingly, and thereby the sucker rod 5 can be driven to move up and down, and the oil pumping pump in the support cylinder 1 is driven to perform oil pumping operation.

[0040] The above embodiments are only preferred technical solutions of the present application, and should not be regarded as a limitation of the present application, and the protection scope of the present application should be the technical solutions recited in the claims, including the equivalent replacement solutions of the technical features recited in the claims. That is, within this range, equivalent replacement improvements are also within the protection scope of the present application.

Claims

1. A hydraulic cylinder for a pumping unit characterized by: The hydraulic cylinder (4) is coaxially arranged above the Christmas tree (2) and is used to drive the sucker rod (5) in the center of the Christmas tree (2) to reciprocate up and down to perform oil pumping operation. The outer cylinder barrel (401) in the hydraulic cylinder (4) is internally fixed with a coaxial inner cylinder barrel (407), the inner cylinder barrel (407) is hollow, and the sucker rod (5) penetrates through the inner cylinder barrel (407) and is arranged coaxially with the inner cylinder barrel (407). The outer cylinder barrel (401) and the inner cylinder barrel (407) are provided with a sliding push barrel (413), the end of the push barrel (413) extends out of the outer cylinder barrel (401), and the push barrel (413) is connected with the sucker rod (5).

2. The hydraulic cylinder for a pumping unit according to claim 1, wherein: The bottom of the hydraulic cylinder (4) is connected with the Christmas tree (2) through the support frame (3), and the sucker rod (5) in the hydraulic cylinder (4) is connected with the sucker rod (5) on the Christmas tree (2) through the sucker rod coupling (6).

3. The hydraulic cylinder for a pumping unit as defined in claim 1 wherein: The tail of the outer cylinder barrel (401) is provided with a mounting seat (402), the outer side of the tail of the inner cylinder barrel (407) is fixedly provided with a positioning ring (404), and the positioning ring (404) is fixedly connected with the mounting seat (402) and the outer cylinder barrel (401) through flange bolts. The end of the mounting seat (402) is further fixedly provided with a connecting flange (403), and the connecting flange (403) is fixedly connected with the support frame (3) on the Christmas tree (2) through flange bolts.

4. The hydraulic cylinder for a pumping unit as defined in claim 1 wherein: One end of the push barrel (413) is fixedly provided with a first piston (405), and the other end is fixedly provided with an end cover (410), the inner and outer sides of the first piston (405) are respectively abutted on the outer cylinder barrel (401) and the inner cylinder barrel (407) to slide through sealing assemblies, The sucker rod (5) penetrates through the end cover (410), the end cover (410) is provided with a sucker rod clamp (7) at the end, and the sucker rod clamp (7) is used to fix the sucker rod (5) on the end cover (410).

5. The hydraulic cylinder of claim 1 wherein: The end of the outer cylinder barrel (401) is fixedly provided with a cylinder cover (409), and the inner side of the cylinder cover (409) is abutted on the outer side of the push barrel (413) through a sealing assembly; The end of the inner cylinder barrel (407) is fixedly provided with a second piston (408), and the outer side of the second piston (408) is abutted on the inner side of the push barrel (413) through a sealing assembly.

6. The hydraulic cylinder of claim 5 wherein: The second piston (408) is provided with a plurality of radial exhaust holes (412) on the side, and the exhaust holes (412) are in communication with the cavity formed between the push barrel (413) and the inner cylinder barrel (407).

7. The hydraulic cylinder of claim 4 wherein: The first piston (405) moves in the cavity formed between the push barrel (413) and the inner cylinder barrel (407), and divides the cavity into a rod cavity and a rodless cavity, and the outer cylinder barrel (401) is provided with radial oil holes on both sides, and the oil holes on both sides are respectively in communication with the rod cavity and the rodless cavity.

8. The hydraulic cylinder of claim 4 wherein: The end cover (410) is provided with a radial through hole on the side, the through hole is in communication with the inner cavity of the inner cylinder barrel (407), and a silencer (411) is mounted on the through hole.

9. The hydraulic cylinder of a pumping unit according to claim 7, wherein: The outer side of the push barrel (413) is provided with a spacing sleeve (406), the spacing sleeve (406) is located in the rod cavity, and the spacing sleeve (406) is used to abut between the first piston (405) and the cylinder cover (409).

10. The use method of the hydraulic cylinder of the oil pumping machine according to any one of claims 1-9, and the method steps are as follows: S1, the hydraulic oil cylinder (4) is installed above the Christmas tree (2) at the wellhead through the support frame (3), and is coaxially arranged with the Christmas tree (2), the sucker rod (5) in the Christmas tree (2) is butted with the sucker rod (5) in the hydraulic oil cylinder (4) through the sucker rod coupling (6); S2, the sucker rod (5) in the hydraulic oil cylinder (4) penetrates the inner cylinder barrel (407) and the end cover (410), and is fixed by the bolts on the sucker rod clamp (7) at the end of the end cover (410); S3, the hydraulic oil cylinder (4) is connected with the hydraulic pump station through the high-pressure oil pipe, and the up-and-down reciprocating movement of the push cylinder (413) in the hydraulic oil cylinder (4) is controlled through the electric control system, so as to drive the sucker rod (5) to drive the oil pump to carry out oil pumping operation.

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