Self-adaptive low-friction polished rod sealer

Abstract

The invention discloses a self-adaptive low-friction polish rod sealer which comprises a blowout preventer shell, two sealing units are arranged in the blowout preventer shell, a spring is arranged between the two sealing units, the top end of the blowout preventer shell is connected with a blowout preventer shell gland, and the top end of the blowout preventer shell gland is connected with a split type wear-resistant sleeve pressing cap. According to the self-adaptive low-friction polish rod sealer, the problems that in the prior art, the maintenance workload is large, and the sealing validity period is short are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field mechanical extraction and pumping well production equipment, and particularly relates to an adaptive low-friction light rod sealer. Background Art

[0002] During the production process of a rod pumping well, the seal between the oil well polished rod and the oil pipe annulus is an important sealing node before the crude oil enters the gathering and transportation process from the wellhead. The wellhead polished rod sealing device is an important tool for achieving closed gathering and transportation. The performance of the wellhead polished rod sealing device is crucial to the sealing effect of the oil wellhead and to ensure the normal production of the pumping well.

[0003] When leaking oil from a wellhead, conventional wellhead sealers often employ methods such as increasing the packing density, adding belts to the packing box, and so on to increase the packing pressure on the polished rod sealer. Alternatively, the sealer structure creates a seal by radially squeezing the polished rod. To ensure a wellhead seal, regular inspections and packing tightening are required, resulting in a high maintenance workload and shortening the packing's useful life, resulting in a shorter seal lifespan. Summary of the Invention

[0004] The purpose of the present invention is to provide an adaptive low-friction light-blocking rod sealer, which solves the problems of heavy maintenance workload and short sealing validity period in the prior art.

[0005] The technical solution adopted by the present invention is an adaptive low-friction light rod sealer, which includes a blowout preventer housing, two sealing units are arranged in the blowout preventer housing, a spring is arranged between the two sealing units, the top end of the blowout preventer housing is connected to the blowout preventer housing cover, and the top end of the blowout preventer housing cover is connected to a split-type wear-resistant sleeve pressure cap.

[0006] The present invention is also characterized in that:

[0007] Each sealing unit includes a lower support ring arranged in the blowout preventer housing, a four-cone sealing rubber core is arranged above the lower support ring, and an upper support ring is arranged above the four-cone sealing rubber core. The top end of the upper support ring contacts one end of the spring.

[0008] The top of the lower support ring is provided with a first upward protruding curved surface and a second upward protruding curved surface, and the first upward protruding curved surface and the second upward protruding curved surface are connected by a plane;

[0009] A first conical surface is provided at the top end of the four-conical sealing rubber core and on a side close to the inner wall of the blowout preventer shell, a second conical surface is provided at the bottom end of the four-conical sealing rubber core and on a side away from the inner wall of the blowout preventer shell, the second conical surface is connected to one end of the first arc surface, the other end of the first arc surface is connected to one end of the third conical surface, the other end of the third conical surface is connected to one end of the second arc surface, the other end of the second arc surface is connected to one end of the fourth arc surface, the other end of the fourth cone surface is connected to one end of the third arc surface, the other end of the third arc surface is connected to the side wall of the four-conical sealing rubber core, the concave surface of the second arc surface is arranged opposite to the concave surfaces of the first and third arc surfaces, the connection between the third conical surface and the first arc surface corresponds to the second upper protruding curved surface, and the connection between the fourth conical surface and the third arc surface corresponds to the first upper protruding curved surface;

[0010] A groove is provided on the top of the upper support ring, which contacts one end of the spring. A fourth arc surface is provided on the bottom end of the upper support ring and close to the inner wall of the blowout preventer shell, which corresponds to the first conical surface.

[0011] A wear-resistant sleeve is provided on the inner wall of the blowout preventer shell and at the bottom of the sealing unit.

[0012] A spring protection sleeve is provided between the spring and the blowout preventer housing.

[0013] A plurality of mounting slots are provided on the side wall of the blowout preventer housing gland, each of which is provided with a petal-type wear-resistant sleeve, and each mounting slot corresponds to a petal-type wear-resistant sleeve gland.

[0014] A second hole is provided on the side wall of each split wear-resistant sleeve close to the split wear-resistant sleeve pressure cap, and a plurality of first holes are provided on the side wall of each split wear-resistant sleeve away from the split wear-resistant sleeve pressure cap. The second hole is connected to the plurality of first holes.

[0015] The thickness of each split-type wear-resistant sleeve is greater than the thickness of the installation groove.

[0016] A dust ring is provided between the blowout preventer casing gland and the split-type wear-resistant sleeve gland.

[0017] The beneficial effects of the present invention are:

[0018] (1) The adaptive low-friction polished rod sealer of the present invention utilizes the wellbore pressure during oil well pumping and production, automatically and dynamically adjusting the sealing pressure, effectively converting the wellbore pressure into a radial sealing effect. Furthermore, the space for installing the spring and the through-hole of the split-type wear-resistant sleeve are pre-filled with grease, which can reduce the polished rod sealing resistance, reduce pumping energy consumption, and extend the effective life of the seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of the adaptive low-friction light-blocking rod sealer of the present invention;

[0020] Figure 2 This is a schematic structural diagram of the blowout preventer housing gland in the adaptive low-friction light rod sealer of the present invention;

[0021] Figure 3 This is a schematic structural diagram of a split-type wear-resistant sleeve in the adaptive low-friction light-blocking rod sealer of the present invention;

[0022] Figure 4 It is a partial schematic diagram of the sealing unit in the adaptive low-friction light rod sealer of the present invention.

[0023] In the figure, 1. BOP housing, 2. wear sleeve, 3. lower support ring, 4. four-cone sealant core, 5. upper support ring, 6. spring protection sleeve, 7. spring, 8. BOP housing gland, 9. split wear sleeve, 10. dust ring, 11. split wear sleeve gland, 12. polished rod;

[0024] 301. First upward protruding curved surface, 302. Second upward protruding curved surface, 303. Plane, 401. First conical surface, 402. Second conical surface, 403. Third conical surface, 404. Fourth conical surface, 405. First arc surface, 406. Second arc surface, 407. Third arc surface, 501. Groove, 502. Fourth arc surface, 801. Mounting slot, 901. First hole, 902. Second hole. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] The self-adaptive low-friction light-blocking rod sealer of the present invention has a structure as follows Figure 1 As shown, it includes a blowout preventer housing 1, two sealing units are arranged in the blowout preventer housing 1, a spring 7 is arranged between the two sealing units, and the sealing function of the oil pipe and the polished rod annulus is realized by the cooperation of the two sealing units and the spring 7. A spring protection sleeve 6 is provided between the spring 7 and the blowout preventer housing 1. By pre-filling grease in the installation space of the spring 7, the polished rod is lubricated to reduce friction resistance while preventing corrosion. The top end of the blowout preventer housing 1 is connected to the blowout preventer housing cover 8, and the top end of the blowout preventer housing cover 8 is connected to a split-type wear-resistant sleeve pressure cap 11, as shown in FIG. Figure 2 As shown, a plurality of mounting slots 801 are provided on the side wall of the blowout preventer housing gland 8, and a petal-type wear-resistant sleeve 9 is provided in each mounting slot 801. The petal-type wear-resistant sleeve 9 is used to achieve the effect of straightening the polished rod and reducing eccentric wear, as shown in FIG. Figure 3As shown, each split wear-resistant sleeve 9 is provided with a second hole 902 on the side wall close to the split wear-resistant sleeve pressure cap 11, and each split wear-resistant sleeve 9 is provided with a plurality of first holes 901 on the side wall away from the split wear-resistant sleeve pressure cap 11. The second hole 902 is connected with the plurality of first holes 901. By filling the second hole 902 with grease, the polished rod 12 is protected from corrosion through the first hole 901 while the polished rod is lubricated to reduce friction resistance. The thickness of each split wear-resistant sleeve 9 is greater than the thickness of the mounting groove 801. The degree of the split wear-resistant sleeve 9 can be ensured to be in contact with the polished rod 12. Each mounting groove 801 corresponds to the split wear-resistant sleeve pressure cap 11. After the split wear-resistant sleeve pressure cap 11 is installed, the split wear-resistant sleeve 9 can be pressed tightly in the mounting groove 801 and in contact with the polished rod 12. A wear-resistant sleeve 2 is provided on the inner wall of the blowout preventer housing 1 and at the bottom of the sealing unit. The wear-resistant sleeve 2 can straighten the polished rod 12 and reduce eccentric wear. A dust ring 10 is provided between the blowout preventer housing gland 8 and the split wear-resistant sleeve pressure cap 11 to block dust.

[0028] like Figure 4 As shown, each sealing unit includes a lower support ring 3 disposed in the blowout preventer housing 1, a four-cone sealing rubber core 4 is disposed above the lower support ring 3, and an upper support ring 5 is disposed above the four-cone sealing rubber core 4, and the top end of the upper support ring 5 contacts one end of the spring 7;

[0029] The top of the lower support ring 3 is provided with a first upward protruding curved surface 301 and a second upward protruding curved surface 302, and the first upward protruding curved surface 301 and the second upward protruding curved surface 302 are connected by a plane 303;

[0030] A first conical surface 401 is provided at the top of the four-conical surface sealing rubber core 4 and on the side close to the inner wall of the blowout preventer shell 1, and a second conical surface 402 is provided at the bottom of the four-conical surface sealing rubber core 4 and on the side away from the inner wall of the blowout preventer shell 1. The second conical surface 402 is connected to one end of the first arc surface 405, the other end of the first arc surface 405 is connected to one end of the third conical surface 403, the other end of the third conical surface 403 is connected to one end of the second arc surface 406, the other end of the second arc surface 406 is connected to one end of the fourth conical surface 404, the other end of the fourth conical surface 404 is connected to one end of the third arc surface 407, and the other end of the third arc surface 407 is connected to the four-conical surface sealing rubber core The side walls of the rubber core 4 are connected, the concave surface of the second arc surface 406 is arranged opposite to the concave surfaces of the first arc surface 405 and the third arc surface 407, the connection between the third cone surface 403 and the first arc surface 405 corresponds to the second upward protruding curved surface 302, and the connection between the fourth cone surface 404 and the third arc surface 407 corresponds to the first upward protruding curved surface 301; when the sealing unit is squeezed, the lower support ring 3 can squeeze the connection between the third cone surface 403 and the first arc surface 405, and the connection between the fourth cone surface 404 and the third arc surface 407, so that the bottom end of the four-cone surface sealing rubber core 4 is deformed and respectively adheres to the polished rod 12 and the inner wall of the blowout preventer shell 1, thereby forming a seal.

[0031] A groove 501 is provided at the top of the upper support ring 5, which contacts one end of the spring 7. A fourth arc surface 502 is provided at the bottom end of the upper support ring 5, close to the inner wall of the blowout preventer housing 1. The fourth arc surface 502 corresponds to the first conical surface 401. When the sealing unit is squeezed, the first conical surface 401 and the fourth arc surface 502 interact with each other, causing the four-conical surface sealing rubber core 4 to deform and fill the rod 12 and the inner wall of the blowout preventer housing 1 tightly, thereby forming a seal.

[0032] The assembly process of the adaptive low-friction light rod sealer of the present invention is as follows: the wear-resistant sleeve 2, the sealing unit at the bottom, the spring protection sleeve 6, the spring 7, and the sealing unit at the top are sequentially installed in the blowout preventer housing 1, wherein the installation order of the sealing unit is the lower support ring 3, the four-cone sealing rubber core 4, and the upper support ring 5. Then, the blowout preventer housing gland 8 is tightened with the blowout preventer housing 1 through threads, the blowout preventer housing gland 8 is installed in the installation groove 801 on the blowout preventer housing gland 8, and then the dust ring 10 is installed above the blowout preventer housing gland 8. Finally, the split-type wear-resistant sleeve gland 11 is tightened with the blowout preventer housing gland 8 through threads to complete the assembly. In the assembled adaptive low-friction light rod sealer, the spring 7 is in a compressed state, and both sealing units are squeezed by the spring to achieve sealing.

[0033] The working process of the adaptive low-friction light-blocking rod sealer of the present invention is as follows: the assembled adaptive low-friction light-blocking rod sealer is connected to the wellhead tee thread or clamp of the oil well (the lower end of the adaptive low-friction light-blocking rod sealer can be configured with different connection forms according to the wellhead conditions), and the adaptive low-friction light-blocking rod sealer is adjusted to a suitable position; a trial pumping is conducted and the degree of compression of the blowout preventer housing gland 8 is adjusted (i.e., the degree to which the sealing unit is squeezed is adjusted); two sealing units are arranged in the blowout preventer housing 1, and a spring 7 is provided between the sealing units to preset a pre-tightening pressure to form an initial sealing pressure (the spring is in a compressed state). During pumping, the pressure in the well acts on the lower end face of the sealing unit located at the upper part, thereby pushing the sealing unit located at the upper part to move upward, increasing the contact stress of the two four-cone sealing rubber cores 4 to enhance the sealing performance; during the upward process, the friction resistance between the light rod and the four-cone sealing rubber core 4 is converted into the sealing pressure of the four-cone sealing rubber core 4 , increasing the compression force on the four-cone sealing rubber core 4 to enhance the sealing effect; during the downward process, the pressure in the well drops, and the lower end surface of the sealing unit at the upper part moves downward. Under the action of the spring 7, the two sealing units at the upper part and the sealing unit at the lower part are restored to their initial state, and the compression force on the two four-cone sealing rubber cores 4 is reduced, thereby reducing the sealing friction resistance of the light rod 12; the space for installing the spring 7 between the two sealing units can be pre-filled with grease, which lubricates the light rod while preventing corrosion and reducing friction resistance. As mentioned above, during the upward and downward process of the light rod 12, the sealing force of the two sealing units is dynamically self-adjusted. During the upward process of the light rod, the pressure in the well increases, and the contact stress of the two four-cone sealing rubber cores 4 increases successively under the action of the pressure in the well to achieve effective sealing. During the downward process, the contact stress of the two four-cone sealing rubber cores 4 is small, thereby reducing friction resistance, and the adaptive well condition reduces friction resistance while sealing.

[0034] The replacement process of the split wear-resistant sleeve 9 and the four-cone sealing rubber core 4 in the adaptive low-friction light-blocking rod sealer of the present invention is as follows: when the split wear-resistant sleeve 9 and the four-cone sealing rubber core 4 are worn, the split wear-resistant sleeve pressure cap 11 and the blowout preventer housing pressure cover 8 are unscrewed in sequence, and the sealing unit, spring protection sleeve 6, spring 7 and the sealing unit at the bottom are taken out. The order of taking out the sealing unit is the upper support ring 5, the four-cone sealing rubber core 4 and the lower support ring 3; the new four-cone sealing rubber core 4 is replaced. Cut it at an angle of 40° to 60° longitudinally (i.e., the cut surface is an inclined surface) and install it in the order of disassembly. During installation, the new four-cone sealing rubber core 4 is inserted into the blowout preventer housing 1 through the incision and through the polished rod 12. The worn split wear-resistant sleeve 9 is removed from the blowout preventer housing gland 8, and a new split wear-resistant sleeve 9 is installed into the blowout preventer housing gland 8. Grease is filled into the second hole 902, and finally the split wear-resistant sleeve gland 11 is tightened. The maintenance is completed and the system is put back into production.

[0035] Example 2

[0036] The present invention provides an adaptive low-friction light rod sealer, comprising a blowout preventer housing 1, wherein two sealing units are provided in the blowout preventer housing 1, a spring 7 is provided between the two sealing units, a spring protection sleeve 6 is provided between the spring 7 and the blowout preventer housing 1, a blowout preventer housing gland 8 is connected to the top end of the blowout preventer housing gland 8, a split-type wear-resistant sleeve pressure cap 11 is connected to the top end of the blowout preventer housing gland 8, a plurality of mounting slots 801 are provided on the side wall of the blowout preventer housing gland 8, a split-type wear-resistant sleeve 9 is provided in each mounting slot 801, and a second hole 902 is provided on the side wall of each split-type wear-resistant sleeve 9 adjacent to the split-type wear-resistant sleeve pressure cap 11. A plurality of first holes 901 are provided on the side wall of each split wear-resistant sleeve 9 away from the split wear-resistant sleeve pressure cap 11, and the second holes 902 are connected to the plurality of first holes 901. The thickness of each split wear-resistant sleeve 9 is greater than the thickness of the mounting groove 801, and each mounting groove 801 corresponds to the split wear-resistant sleeve pressure cap 11. After the split wear-resistant sleeve pressure cap 11 is installed, it can be ensured that the split wear-resistant sleeve 9 is pressed tightly in the mounting groove 801 and contacts the polished rod 12. A wear-resistant sleeve 2 is provided on the inner wall of the blowout preventer housing 1 and at the bottom of the sealing unit, and a dust ring 10 is provided between the blowout preventer housing gland 8 and the split wear-resistant sleeve pressure cap 11.

[0037] Example 3

[0038] The adaptive low-friction polished rod sealer of the present invention includes a blowout preventer housing 1, two sealing units are arranged in the blowout preventer housing 1, a spring 7 is arranged between the two sealing units, the top of the blowout preventer housing 1 is connected to the blowout preventer housing gland 8, the top of the blowout preventer housing gland 8 is connected to the petal-type wear-resistant sleeve pressure cap 11, and a plurality of mounting grooves 801 are provided on the side wall of the blowout preventer housing gland 8, each mounting groove 801 is provided with a petal-type wear-resistant sleeve 9, each mounting groove 801 corresponds to the petal-type wear-resistant sleeve pressure cap 11, and after the petal-type wear-resistant sleeve pressure cap 11 is installed, it can be ensured that the petal-type wear-resistant sleeve 9 is pressed tightly in the mounting groove 801 and contacts the polished rod 12.

Claims

1. Adaptive low friction light blocking rod sealer, characterized by: The invention comprises a blowout preventer housing (1), wherein two sealing units are arranged in the blowout preventer housing (1), a spring (7) is arranged between the two sealing units, the top end of the blowout preventer housing (1) is connected to a blowout preventer housing gland (8), and the top end of the blowout preventer housing gland (8) is connected to a split-type wear-resistant sleeve gland (11).

2. The adaptive low-friction light-blocking rod sealer according to claim 1, characterized in that: Each of the sealing units comprises a lower support ring (3) arranged in the blowout preventer housing (1); a four-cone sealing rubber core (4) is arranged above the lower support ring (3); an upper support ring (5) is arranged above the four-cone sealing rubber core (4); and the top end of the upper support ring (5) contacts one end of a spring (7).

3. The adaptive low-friction light-blocking rod sealer according to claim 2, characterized in that: A first upwardly protruding curved surface (301) and a second upwardly protruding curved surface (302) are provided on the top of the lower support ring (3); the first upwardly protruding curved surface (301) and the second upwardly protruding curved surface (302) are connected via a plane (303); A first conical surface (401) is provided at the top end of the four-conical surface sealing rubber core (4) and on the side close to the inner wall of the blowout preventer shell (1), and a second conical surface (402) is provided at the bottom end of the four-conical surface sealing rubber core (4) and on the side away from the inner wall of the blowout preventer shell (1), the second conical surface (402) is connected to one end of the first arc surface (405), the other end of the first arc surface (405) is connected to one end of the third conical surface (403), the other end of the third conical surface (403) is connected to one end of the second arc surface (406), the other end of the second arc surface (406) is connected to the fourth conical surface ( The fourth conical surface (404) is connected to one end of the third arc surface (407), the other end of the third arc surface (407) is connected to the side wall of the four-conical surface sealing rubber core (4), the concave surface of the second arc surface (406) is arranged opposite to the concave surfaces of the first arc surface (405) and the third arc surface (407), the connection between the third conical surface (403) and the first arc surface (405) corresponds to the second upper protruding curved surface (302), and the connection between the fourth conical surface (404) and the third arc surface (407) corresponds to the first upper protruding curved surface (301); The top of the upper support ring (5) is provided with a groove (501), and the groove (501) contacts one end of the spring (7). The bottom end of the upper support ring (5) and the side close to the inner wall of the blowout preventer shell (1) are provided with a fourth arc surface (502), and the fourth arc surface (502) corresponds to the first conical surface (401).

4. The adaptive low-friction light-blocking rod sealer according to claim 1, characterized in that: A wear-resistant sleeve (2) is provided on the inner wall of the blowout preventer housing (1) and at the bottom of the sealing unit.

5. The adaptive low-friction light-blocking rod sealer according to claim 1, characterized in that: A spring protection sleeve (6) is provided between the spring (7) and the blowout preventer housing (1).

6. The adaptive low-friction light-blocking rod sealer according to claim 1, characterized in that: A plurality of mounting slots (801) are provided on the side wall of the blowout preventer housing gland (8), each of which is provided with a split-type wear-resistant sleeve (9), and each of which corresponds to a split-type wear-resistant sleeve gland (11).

7. The adaptive low-friction light-blocking rod sealer according to claim 6, characterized in that: A second hole (902) is provided on the side wall of each of the split-type wear-resistant sleeves (9) close to the split-type wear-resistant sleeve pressure cap (11), and a plurality of first holes (901) are provided on the side wall of each of the split-type wear-resistant sleeves (9) away from the split-type wear-resistant sleeve pressure cap (11), and the second holes (902) are all connected to the plurality of first holes (901).

8. The adaptive low-friction light-blocking rod sealer according to claim 6, characterized in that: The thickness of each of the split-type wear-resistant sleeves (9) is greater than the thickness of the installation slot (801).

9. The adaptive low-friction light-blocking rod sealer according to claim 1, characterized in that: A dust ring (10) is provided between the blowout preventer housing gland (8) and the split-type wear-resistant sleeve gland (11).

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