Oil wellhead anti-dry wear sealing method and anti-dry wear sealing packing box

Abstract

The present invention relates to the technical field of wellhead sealing, and is a method for sealing against dry wear of an oil pumping wellhead and a sealing packing box against dry wear. The former includes the following steps: S1, the lower end of the lower packing box with a lower support ring fixed on the inner side of the lower part is passed through the outer side of the light rod and fixedly installed with the upper end of the wellhead equipment. The present invention has a reasonable and compact structure, and lubricating liquid is regularly added to the lubricating liquid filling component, and the lubricating liquid is injected into the liquid inlet by the lubricating liquid filling component, and then the lubricating liquid passes through the oil hole of the oil pressure sleeve and adheres to the outer side of the light rod, so that the light rod is lubricated. The first sealing component and the second sealing component are arranged to prevent the lubricating liquid from being easily lost, so that the light rod can be fully lubricated, and dry wear of the light rod can be prevented, and continuous lubrication of the oil pumping wellhead seal can be achieved, and the maintenance of the sealing component is more convenient. When the intermittent oil well is only venting gas, the phenomenon of heating of the light rod caused by dry wear of the light rod and the packing and oil leakage after the seal fails can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of wellhead sealing, in particular to an anti-dry wear sealing method for an oil pumping wellhead and an anti-dry wear sealing packing box. Background Art

[0002] During the oil pumping production process, the bare rod and the sealing material in the packing box rub against each other for a long time due to the up and down movement. This friction causes the sealing material to wear, and eventually develops into the wellhead packing and the bare rod are not sealed enough, resulting in oil leakage. When the fluid in the well leaks out of the well without control, it is called "oil leakage" on site. Oil leakage will lead to crude oil waste, environmental pollution, and increased labor. While polluting the environment, it also affects the normal production of oil wells. The number of oil wells in the oil field accounts for about 90% of the total number of wells. In order to prevent oil leakage, in addition to improving the sealing device, it is to tighten the packing and replace the packing in time. Tightening the packing and replacing the packing are the main tasks at the oil production site. Frequent replacement of packing operations will also affect the production time rate.

[0003] The wellhead sealing device is an important component to prevent the leakage of wellhead fluid during the production process of the oil well. The working environment of the wellhead sealing device is relatively harsh. It needs to withstand the test of long-term repeated shuttling, friction, eccentric wear, shaking, etc. of the polished rod, keep the packing in close contact with the surface of the polished rod at all times, and prevent the fluid (oil, gas, water), mechanical impurities, etc. in the well from leaking out of the well.

[0004] In order to improve the sealing performance of the oil wellhead, many sealing methods are used. For example, the Chinese patent document with publication number CN113047801A discloses a sealing method for a wellhead packing box and a wellhead packing box device. The sealing method for the wellhead packing box includes: opening the gland of the packing box and taking out the original sealing filler; spirally winding a sealing rope soaked in grease on the bare rod and putting it into the packing box; pressing the sealing rope through the gland and the upper pressure block, and installing the gland on the packing box. The sealing method of the wellhead packing box adopts a primary sealing method to seal the inner side of the packing box and the outer side of the polished rod. In this way, when the surface of the polished rod is rough or damaged, the wear of the packing on the polished rod will be accelerated, shortening the service life of the packing. Even if the sealing rope is filled with grease, when the oil well intermittently emits gas and liquid, the oil well only emits gas but not liquid, and the polished rod and packing lose lubrication. If the polished rod and packing are dry-ground for a long time, the tightly pressed packing will become hot, accelerating the loss of packing. In severe cases, the polished rod will turn blue, lose its seal and leak oil.

[0005] The Chinese patent document with the publication number CN117266778A discloses a method for sealing a bare rod wellhead of an oil pumping unit and a sealing packing for an oil pumping unit. The method for sealing a bare rod wellhead of an oil pumping unit comprises the following steps: taking an annular gasket and putting it on the bare rod and putting it into the bottom of the wellhead packing box cavity, then alternately putting rubber strips and semi-solid lubricants into the packing box cavity until the packing sealing box is filled, then taking an annular gasket and putting it on the bare rod, installing the gland and the packing pressure cap, and tightening it; when putting in the rubber strip, the rubber strip is placed around the bare rod and spread in a layer in the packing box cavity. The method for sealing a bare rod wellhead of an oil pumping unit requires multiple layers of semi-solid lubricants and rubber strips to be alternately stacked to form a sealing layer. The height of the general sealing layer is about 100 mm. The method for sealing a bare rod wellhead of an oil pumping unit requires multiple layers to be stacked, and the operation of putting in the rubber strips is relatively difficult, time-consuming and labor-intensive.

[0006] The Chinese patent document with publication number CN118088092A discloses a flexible sucker rod wellhead sealing method, which includes the following method steps: S1, factory installation of the device: before the flexible sucker rod and the combined joint are installed, the gland, the compression sleeve, the ball head box, the ball seat, the fastening sleeve, the inner sealing ring, the metal elastic sealing ring, the U-shaped box and the flat plate are sleeved on the flexible sucker rod; S2, on-site installation: the flexible sucker rod is connected to the rigid sucker rod, and the ball seat is fixed on the wellhead, and then the annular pressure disc, the elastic ring, and the elastic sealing ring are sleeved into the U-shaped box; S3, wellhead alignment adjustment: start the equipment to operate, so that the flexible sucker rod The oil rod moves down to the lowest point, then moves up to the middle position of the full stroke and then stops, so that the U-shaped box and the flexible sucker rod are automatically aligned, and the fastening sleeve on the outer wall of the ball head box is tightened; S4, seal tightness adjustment: turn the handle on the gland, stop the operation when it is difficult to turn the handle, and then start the pumping equipment. After the flexible sucker rod completes several strokes, the well fluid rises to the wellhead. During the process of wellhead pressure rising, observe the crude oil adhesion on the flexible sucker rod. If crude oil appears, stop the machine immediately and adjust the seal tightness of the metal elastic sealing ring and the flexible sucker rod; S5, bolt tightening seal: turn the adjustment sleeve on the ball head box Adjust the bolts so that the adjusting bolts are screwed into the several long holes set on the lower side of the U-shaped box, so that the tightening bolts push the annular pressure disc and squeeze the elastic ring, so that the outer ring of the metal elastic sealing ring is compressed to cause the inner hole to shrink, and the flexible sucker rod is tightly held to achieve the sealing effect; S6, secondary adjustment: start the pumping equipment, observe the crude oil adhesion on the flexible sucker rod, check whether there is crude oil leakage between the gland and the flexible sucker rod, and gradually increase the tightening operation of the adjusting bolts until there is no crude oil adhesion on the flexible sucker rod and no crude oil leakage between the gland and the flexible sucker rod, stop twisting the adjusting bolts, tighten the locking nuts, and stop the equipment Operation; S7, double-layer sealing: twist the handle on the gland, press the elastic sealing ring through the compression sleeve and the flat plate, so that the elastic sealing ring holds the flexible sucker rod tightly to achieve the sealing effect, and cooperate with the metal elastic sealing ring to perform double-layer sealing on the flexible sucker rod; S8, adjustment during use: after the equipment has been running for a long time, if crude oil is attached to the flexible sucker rod, it is necessary to gradually increase the tightening operation of the adjustment bolt until there is no crude oil attached to the flexible sucker rod; at the same time, in the shutdown state, twist the handle on the gland, press the elastic sealing ring through the compression sleeve and the flat plate, so that the elastic sealing ring holds the flexible sucker rod tightly. This flexible sucker rod wellhead sealing method needs to give priority to the flexible sucker rod to cooperate with the pumping equipment before operation, and realize the alignment of the flexible sucker rod and the center of the U-shaped box during operation. The operation is difficult, which requires a lot of maintenance time and high maintenance costs.

[0007] Although the above-mentioned wellhead sealing method alleviates the problem of oil leakage due to failure of the wellhead seal, it is difficult to operate, requires a lot of maintenance time, and has high maintenance costs. In addition, for intermittent oil wells, the polished rods are prone to lose lubrication, causing the polished rods to become hot and dry, and ultimately causing the sealing material to wear out quickly and cause oil leakage. Summary of the invention

[0008] The present invention provides an anti-dry wear sealing method for an oil pumping wellhead and an anti-dry wear sealing packing box, which overcome the deficiencies of the above-mentioned prior art and can effectively solve the problems of difficult operation and high maintenance cost of the existing wellhead sealing method.

[0009] One of the technical solutions of the present invention is achieved by the following measures: A method for sealing an oil wellhead against dry wear, comprising the following steps:

[0010] S1, the lower end of the lower packing box with the lower support ring fixed on the inner side of the lower part passes through the outer side of the polished rod and is fixedly installed together with the upper end of the wellhead equipment, and the inner wall of the lower packing box above the lower support ring is a conical surface with a larger upper part and a smaller lower part;

[0011] S2, install the lower packing in the annulus between the inner side of the lower packing box and the outer side of the polished rod, including:

[0012] Stacking a plurality of first sealing assemblies from bottom to top in sequence on the upper end of the lower support ring platform, the first sealing assemblies comprising an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring being a trapezoid with a narrow inner side and a wide outer side; the cross section of the lower sealing ring being a trapezoid with a wide inner side and a narrow outer side, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, and the outer sides of the upper sealing ring and the lower sealing ring are both provided with a cut of 20 to 45 degrees;

[0013] Alternatively, a lower auxiliary sealing ring is placed on the upper end of the upper sealing ring at the top, the cross section of the lower auxiliary sealing ring is rectangular, and a cut of 20 to 45 degrees is provided on the outer side of the lower auxiliary sealing ring;

[0014] S3, the lower end of the middle box with a liquid inlet connected to the inside and outside is passed through the outside of the polished rod and then screwed together with the upper end of the lower packing box;

[0015] S4, screwing the outer side of the upper part of the oil pressure sleeve having at least one oil hole communicating with the inner and outer sides at intervals on the outer side together with the inner side of the lower end of the upper packing box;

[0016] S5, pass the lower end of the oil pressure sleeve through the outside of the polished rod and place it on the lower auxiliary sealing ring or the upper end of the first sealing assembly at the top, and fix the lower end of the upper packing box with the upper support ring platform fixed on the inner side of the lower part and the upper end of the middle box together, the inner wall of the upper packing box above the upper support ring platform is a conical surface with a larger upper part and a smaller lower part, and adjust the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod;

[0017] S6, install the packing, including:

[0018] A plurality of second sealing assemblies are sequentially mounted in the annular space between the inner annular surface of the upper support ring platform and the outer side of the polished rod from bottom to top, wherein the second sealing assemblies have the same structure as the first sealing assemblies;

[0019] Alternatively, an upper auxiliary sealing ring is placed on the upper end of the uppermost second sealing assembly, and the upper auxiliary sealing ring has the same structure as the lower auxiliary sealing ring;

[0020] S7, passing the pressing piston and the compression spring through the outer side of the polished rod in sequence and stacking them on the upper auxiliary sealing ring or the upper end of the second sealing assembly at the top;

[0021] S8, passing the lower part of the upper gland through the outer side of the polished rod and screwing it together with the upper part of the upper packing box, adjusting the number of rotations of the upper gland so that the second sealing assembly is in sealing contact with the outer side of the polished rod;

[0022] S9, the liquid outlet and the liquid inlet of the lubricating liquid filling assembly are fixedly connected, and the lubricating liquid is filled into the middle box through the lubricating liquid filling assembly.

[0023] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0024] Preferably, step S4 is specifically as follows: coaxially sleeve the copper wear-resistant sleeve on the inner side of the lower part of the upper packing box below the upper support ring, and fix the upper end of the oil pressure sleeve with at least one oil hole connected inside and outside distributed on the outside to the lower end of the upper packing box, so that the upper end of the oil pressure sleeve and the lower end of the wear-resistant sleeve are in contact with each other.

[0025] Preferably, step S5 specifically comprises: passing the lower end of the oil pressure sleeve through the outside of the polished rod and placing it on the upper end of the lower auxiliary sealing ring or the topmost first sealing assembly; screwing the outer side of the lower end of the upper packing box with the upper supporting ring platform fixed on the inner side of the lower part and the inner side of the upper part of the middle box together; the inner wall of the upper packing box above the upper supporting ring platform is a conical surface with a larger upper part and a smaller lower part; adjusting the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod; providing a sealing ring groove with an opening upward on the inner side of the upper end of the middle box; installing a first sealing component at the bottom of the sealing ring groove; screwing the outer side of the lower part of the lower cover into the sealing ring groove so that the lower end of the lower cover and the upper end of the first seal are in contact with each other.

[0026] As a preferred embodiment, the lubricating liquid filling assembly in the above step S9 includes an oil tank, a piston, a screw rod and a first plug. The oil tank is in the shape of a cylinder with an open upper end and a closed lower end. The outer side of the lower end of the oil tank is provided with a liquid outlet connected inside and outside, a first liquid inlet pipe is fixedly connected between the liquid outlet and the liquid inlet, a first regulating valve is installed on the first liquid inlet pipe, a first plug is detachably fixedly installed on the upper end of the oil tank, a threaded hole that passes through from top to bottom is provided in the center of the first plug, the outer side of the screw rod is screwed into the threaded hole, a threaded groove opening downward is provided at the lower end of the screw rod, a connecting bolt is screwed in the threaded groove, the piston is sleeved on the inner side of the oil tank and a mounting groove opening upward is provided at the upper end, the lower end of the connecting bolt is sleeved in the mounting groove, a sealing ring platform is fixed on the outer side of the lower end of the piston, a small pressure cover is screwed on the outer side of the upper end of the piston, a hanging ring platform in contact with the upper end surface of the head of the connecting bolt is fixed on the inner side of the upper end of the small pressure cover, and a second sealing member is installed between the lower end of the small pressure cover and the upper end of the sealing ring platform.

[0027] As another preferred embodiment, the lubricating fluid filling assembly in step S9 includes a liquid storage tank, a first oil pipe coupling, a second oil pipe coupling, a second plug, a third plug and a second liquid inlet pipe, the outer side of the upper part of the liquid storage tank is fixedly connected to the first oil pipe coupling, the upper end of the first oil pipe coupling is fixedly installed with the second plug, the lower end of the liquid storage tank is fixedly connected to a connecting short section, the lower end of the connecting short section is detachably fixedly installed with a second oil pipe coupling, the lower end of the second oil pipe coupling is detachably fixedly installed with a third plug, a second liquid inlet pipe is fixedly connected between the second oil pipe coupling and the liquid inlet, and a second regulating valve is installed on the second liquid inlet pipe.

[0028] The second technical solution of the present invention is achieved through the following measures: an anti-dry wear sealing packing box, including a lubricating liquid filling assembly, an upper gland, an upper packing box, a middle box, a lower packing box, an upper packing and a lower packing, wherein the upper gland, the upper packing box, the middle box and the lower packing box are screwed together in sequence from top to bottom, an upper support ring platform is fixed to the inner side of the upper part of the upper packing box, an upper packing is arranged on the upper end of the upper support ring platform, a clamping piston is installed on the upper end of the upper packing, and the upper end of the clamping piston is connected to the upper inner part of the upper gland. A compression spring is installed between the sides, a lower supporting ring platform is fixed to the inner side of the lower part of the lower packing box, a lower packing is installed on the upper end of the lower supporting ring platform, an oil pressure sleeve located in the lower packing box is provided at the upper end of the lower packing, at least one oil hole connected inside and outside is distributed at intervals on the outside of the oil pressure sleeve, the upper part of the oil pressure sleeve is screwed together with the inner side of the lower part of the upper packing box, a liquid inlet connected inside and outside is provided on the outer side of the middle part of the middle box, and the liquid outlet of the lubricating liquid filling assembly is fixedly connected to the liquid inlet.

[0029] The following is a further optimization and / or improvement of the second technical solution of the above invention:

[0030] Preferably, the inner wall of the lower packing box above the lower support ring platform is a conical surface with a larger upper part and a smaller lower part, the lower packing includes a plurality of first sealing components stacked sequentially from bottom to top on the inner side of the upper support ring platform, the first sealing component includes an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring is a right-angled trapezoid with a narrow inner part and a wide outer part, the cross section of the lower sealing ring is a right-angled trapezoid with a wide inner part and a narrow outer part, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, and the outer sides of the upper sealing ring and the lower sealing ring are both provided with a cut of 20 to 45 degrees;

[0031] Alternatively, the lower packing includes a lower auxiliary sealing ring and a plurality of first sealing assemblies stacked sequentially from bottom to top on the inner side of the upper support ring platform, the first sealing assembly includes an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring is a right-angled trapezoid with a narrow inner side and a wide outer side, the cross section of the lower sealing ring is a right-angled trapezoid with a wide inner side and a narrow outer side, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, a lower auxiliary sealing ring is installed on the upper end of the uppermost upper sealing ring, the cross section of the lower auxiliary sealing ring is a rectangle, and the outer sides of the upper sealing ring, the lower sealing ring and the lower auxiliary sealing ring are all provided with a cut of 20 to 45 degrees;

[0032] The inner wall of the upper packing box corresponding to the position above the upper supporting ring platform is a conical surface with a larger upper portion and a smaller lower portion. The upper packing has the same structure as the lower packing and is installed on the upper end of the upper supporting ring platform.

[0033] Preferably, the central axis of the inner ring surface of the upper sealing ring is coaxial with the central axis of the outer ring surface or is provided with an eccentricity, and the central axis of the inner ring surface of the lower sealing ring of each first sealing assembly is collinear with the central axis of the inner ring surface of the upper sealing ring.

[0034] Preferably, the taper of the inner wall of the lower packing box above the lower support ring is 1:7 to 1:1.

[0035] Preferably, a sealing ring groove is provided on the inner side of the upper end of the middle box, a lower pressure cover is screwed into the sealing ring groove, and a first sealing member is installed between the lower end of the lower pressure cover and the inner side of the lower part of the sealing ring groove.

[0036] Preferably, a copper wear-resistant sleeve sleeved in the upper packing box is provided between the lower end of the upper support ring platform and the upper end of the oil pressure sleeve.

[0037] Preferably, the lubricating liquid filling assembly comprises an oil tank, a piston, a screw rod and a first plug, the oil tank is in the shape of a cylinder with an open upper end and a closed lower end, the outer side of the lower end of the oil tank is provided with a liquid outlet connected inside and outside, a first liquid inlet pipe is fixedly connected between the liquid outlet and the liquid inlet, a first regulating valve is installed on the first liquid inlet pipe, the upper end of the oil tank is detachably and fixedly installed with a first plug, a threaded hole that passes through from top to bottom is provided in the center of the first plug, the outer side of the screw rod is screwed into the threaded hole, the lower end of the screw rod is provided with a threaded groove opening downward, a connecting bolt is screwed in the threaded groove, the piston is sleeved on the inner side of the oil tank and the upper end is provided with a mounting groove opening upward, the lower end of the connecting bolt is sleeved in the mounting groove, a sealing ring platform is fixed on the outer side of the lower end of the piston, a small pressure cover is screwed on the outer side of the upper end of the piston, a hanging ring platform in contact with the upper end surface of the head of the connecting bolt is fixed on the inner side of the upper end of the small pressure cover, and a second sealing member is installed between the lower end of the small pressure cover and the upper end of the sealing ring platform.

[0038] Preferably, the lubricating fluid filling assembly includes a liquid storage tank, a first oil pipe coupling, a second oil pipe coupling, a second plug, a third plug and a second liquid inlet pipe. The outer side of the upper portion of the liquid storage tank is fixedly connected to the first oil pipe coupling, the upper end of the first oil pipe coupling is fixedly installed with the second plug, the lower end of the liquid storage tank is fixedly connected to a connecting short section, the lower end of the connecting short section is detachably fixedly installed with a second oil pipe coupling, the lower end of the second oil pipe coupling is detachably fixedly installed with a third plug, a second liquid inlet pipe is fixedly connected between the second oil pipe coupling and the liquid inlet, and a second regulating valve is installed on the second liquid inlet pipe.

[0039] The present invention has a reasonable and compact structure. Lubricating liquid is regularly added to the lubricating liquid filling component. The lubricating liquid can be engine oil, transmission oil, butter, crude oil, etc. The lubricating liquid is injected into the liquid inlet by the lubricating liquid filling component, and then the lubricating liquid passes through the oil hole of the oil pressure sleeve and adheres to the outside of the polished rod, so that the polished rod is lubricated. The arrangement of the first sealing component and the second sealing component can prevent the lubricating liquid from being easily lost, so that the polished rod can be fully lubricated and dry grinding of the polished rod can be prevented.

[0040] After the middle box and the lower packing box are disassembled, the upper packing box, the middle box, the oil pressure sleeve and the lubricating liquid filling assembly can be lifted upward as a whole, and the lower packing can be added to the lower packing box. There is no need to disassemble the middle box and the lubricating liquid filling assembly separately, which effectively solves the problem of the difficulty in updating the first sealing assembly in the lower packing box.

[0041] The upper gland is tightened regularly, and the upper gland acts on the second sealing assembly through the compression spring and the compression piston. The compression spring can be an existing well-known pressure spring. In this way, the compression force of the second sealing assembly can be maintained after the upper gland is tightened. When the second sealing assembly is worn, it can still wrap the polished rod tightly under the downward pressure to maintain a lasting seal on the polished rod.

[0042] The anti-dry wear sealing method for the oil pumping wellhead and the anti-dry wear sealing packing box can achieve continuous lubrication of the oil pumping wellhead seal, make the maintenance of the sealing component more convenient, and avoid the phenomenon of lubricating fluid leaking downward or upward. When the intermittent oil well is only emitting gas, it can avoid the phenomenon of the light rod becoming hot due to dry wear between the light rod and the packing, and oil leakage after the seal fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Attached Figure 1 This is a schematic diagram of the process structure of the first embodiment of the present invention.

[0044] Attached Figure 2 It is a schematic diagram of the front and cross-sectional structure of the lubricating fluid filling assembly in embodiments 1 to 4 of the present invention.

[0045] Attached Figure 3 This is a schematic diagram of the front cross-sectional structure of the lubricating fluid filling assembly in Example 5 of the present invention.

[0046] Attached Figure 4 The main structure diagram of the lower packing in the first embodiment of the present invention is shown in FIG. Figure 1 .

[0047] Attached Figure 5 The main cross-sectional structure diagram of the lower packing in the first embodiment of the present invention is shown in FIG. Figure 1 .

[0048] Attached Figure 6 The main structure diagram of the lower packing in the first embodiment of the present invention is shown in FIG. Figure 2 .

[0049] Attached Figure 7 The main cross-sectional structure diagram of the lower packing in the first embodiment of the present invention is shown in FIG. Figure 2 .

[0050] The codes in the attached drawings are: 1 is the upper gland, 2 is the upper packing box, 3 is the middle box, 4 is the lower packing box, 5 is the upper support ring, 6 is the clamping piston, 7 is the compression spring, 8 is the lower support ring, 9 is the oil pressure sleeve, 10 is the oil hole, 11 is the liquid inlet, 12 is the upper sealing ring, 13 is the lower sealing ring, 14 is the upper packing, 15 is the lower gland, 16 is the first sealing member, 17 is the wear-resistant sleeve, 18 is the oil tank, 19 is the piston, 20 is the screw rod, 21 is the first plug, 22 is the first liquid inlet pipeline, 23 is the first regulating valve, 24 is the connecting bolt, 25 is the sealing ring platform, 26 is the small pressure cover, 27 is the second sealing member, 28 is the liquid storage tank, 29 is the first oil pipe coupling, 30 is the second oil pipe coupling, 31 is the second plug, 32 is the second liquid inlet pipeline, 33 is the connecting short section, 34 is the second regulating valve, 35 is the bare rod, 36 is the hanging ring platform, 37 is the lower auxiliary sealing ring, and 38 is the third plug. DETAILED DESCRIPTION

[0051] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0052] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The layout is described in detail, such as the positional relationship of front, back, top, bottom, left, right, etc., which is based on the attached manual. Figure 1 The layout direction is determined by the

[0053] The present invention will be further described below in conjunction with embodiments and drawings:

[0054] Embodiment 1: As shown in the attached Figures 1 to 7 As shown, the method for sealing the pumping wellhead against dry wear comprises the following steps:

[0055] S1, the lower end of the lower packing box 4 with the lower support ring platform 8 fixed on the inner side of the lower part passes through the outer side of the polished rod 35 and is fixedly installed together with the upper end of the rubber gate, and the inner wall of the lower packing box 4 above the lower support ring platform 8 is a conical surface with a larger upper part and a smaller lower part;

[0056] S2, installing the lower packing in the annulus between the inner side of the lower packing box 4 and the outer side of the polished rod 35, including:

[0057] A plurality of first sealing components are stacked in sequence from bottom to top on the upper end of the lower support ring platform 8, wherein the first sealing components include an upper sealing ring 12 and a lower sealing ring 13, wherein the cross section of the upper sealing ring 12 is a trapezoidal shape that is narrow inside and wide outside; the cross section of the lower sealing ring 13 is a trapezoidal shape that is wide inside and narrow outside, and the upper end surface of the lower sealing ring 13 matches the lower end surface of the upper sealing ring 12, and the outer sides of the upper sealing ring 12 and the lower sealing ring 13 are both provided with a cut of 20 to 45 degrees;

[0058] Alternatively, a plurality of first sealing components are stacked in sequence from bottom to top on the upper end of the lower support ring platform 8, wherein the first sealing components include an upper sealing ring 12 and a lower sealing ring 13, wherein the cross section of the upper sealing ring 12 is a trapezoidal shape that is narrow inside and wide outside; the cross section of the lower sealing ring 13 is a trapezoidal shape that is wide inside and narrow outside, and the upper end surface of the lower sealing ring 13 matches the lower end surface of the upper sealing ring 12, and the outer sides of the upper sealing ring 12 and the lower sealing ring 13 are both provided with a cut of 20 to 45 degrees, and a lower auxiliary sealing ring 37 is placed on the upper end of the upper sealing ring 12 at the top, wherein the cross section of the lower auxiliary sealing ring 37 is a rectangle, and the outer side of the lower auxiliary sealing ring 37 is provided with a cut of 20 to 45 degrees;

[0059] S3, the lower end of the middle box 3 with the liquid inlet 11 communicating with the inside and outside is passed through the outside of the polished rod 35 and then screwed together with the upper end of the lower packing box 4;

[0060] S4, screw the outer side of the upper part of the oil pressure sleeve 9, which has at least one oil hole 10 that is connected to the inside and outside, together with the inner side of the lower end of the upper packing box 2;

[0061] S5, pass the lower end of the oil pressure sleeve 9 through the outside of the polished rod 35 and place it on the lower auxiliary sealing ring 37 or the upper end of the first sealing assembly at the top, and fix the lower end of the upper packing box 2 with the upper support ring 5 fixed on the inner side of the lower part and the upper end of the middle box 3 together, the inner wall of the upper packing box 2 above the upper support ring 5 is a conical surface with a larger upper part and a smaller lower part, and adjust the number of rotations of the upper packing box 2 so that the first sealing assembly is in sealing contact with the outer side of the polished rod 35;

[0062] S6, install the packing, including:

[0063] A plurality of second sealing components are sequentially mounted in the annular space between the inner annular surface of the upper support ring platform 5 and the outer side of the polished rod 35 from bottom to top. The structure of the second sealing component is the same as that of the first sealing component.

[0064] Alternatively, a plurality of second sealing components are sequentially mounted in the annular space between the inner annular surface of the upper support ring platform 5 and the outer side of the polished rod 35 from bottom to top, wherein the second sealing component has the same structure as the first sealing component, and an upper auxiliary sealing ring is placed on the upper end of the uppermost second sealing component, wherein the upper auxiliary sealing ring has the same structure as the lower auxiliary sealing ring 37;

[0065] S7, pass the pressing piston 6 and the compression spring 7 through the outer side of the polished rod 35 in sequence and then stack them on the upper auxiliary sealing ring or the upper end of the second sealing assembly at the top;

[0066] S8, the lower part of the upper gland 1 passes through the outer side of the polished rod 35 and is screwed together with the upper part of the upper packing box 2, and the number of rotations of the upper gland 1 is adjusted so that the second sealing assembly is in sealing contact with the outer side of the polished rod 35;

[0067] S9, the liquid outlet of the lubricating liquid filling assembly is fixedly connected to the liquid inlet 11, and lubricating liquid is filled into the middle box 3 through the lubricating liquid filling assembly.

[0068] To facilitate disassembly and assembly, in step S1, the lower end of the lower packing box 4 is fixedly installed together with the upper end of the wellhead equipment by means of a threaded connection, and the wellhead equipment is a rubber gate; in step S5, the lower end of the upper packing box 2 is fixedly installed together with the upper end of the middle box 3 by means of a threaded connection. When the upper packing box 2 is rotated and tightened, the oil pressure sleeve 9 not only plays the role of lubricating the polished rod 35 with oil, but also can play the role of transmitting the pressure of the upper packing box 2, thereby compressing the first sealing assembly to ensure the sealing effect between the first sealing assembly and the polished rod 35.

[0069] In order to facilitate the disassembly and assembly of the upper sealing ring 12 and the lower sealing ring 13, the outer sides of the upper sealing ring 12 and the lower sealing ring 13 are provided with cuts of 20 to 45 degrees, and two adjacent cuts are staggered or the directions of two adjacent cuts are opposite and staggered.

[0070] In order to increase the force-bearing area at both ends of the compression spring 7 and avoid failure of the compression spring 7 after the force is concentrated, the outer side of the upper end of the compression piston 6 bulges outward to form an outer ring platform, or the upper end of the outer side of the outer ring platform bulges upward to form a sleeve that is sleeved on the outer side of the lower part of the compression spring 7. This can prevent the compression spring 7 from being offset and wearing against the light rod 35. The compression spring 7 is a well-known technology. In the initial state, the compression force of the compression spring 7 on several second sealing components is 1000 to 8000N, ensuring that the second sealing components are in sealing contact with the outer side of the light rod 35.

[0071] A lower auxiliary sealing ring 37 is placed on the upper end of the upper sealing ring 12 at the top. The cross-section of the lower auxiliary sealing ring 37 is rectangular. A 20 to 45 degree cut is provided on the outer side of the lower auxiliary sealing ring 37. The thickness of the first sealing component can be twice the thickness of the lower auxiliary sealing ring 37. After stacking several first sealing components from bottom to top on the upper end of the lower support ring platform 8, another lower auxiliary sealing ring 37 is placed. This can avoid the phenomenon that the thickness of several first sealing components is too large or too small when they are stacked from bottom to top on the upper end of the lower support ring platform 8.

[0072] Lubricating liquid is regularly added to the lubricating liquid filling assembly. The lubricating liquid may be engine oil, transmission oil, butter, crude oil, etc. The lubricating liquid is injected into the liquid inlet 11 by the lubricating liquid filling assembly, and then the lubricating liquid passes through the oil hole 10 of the oil pressure sleeve 9 and adheres to the outside of the polished rod 35, so that the polished rod 35 is lubricated. The setting of the first sealing assembly and the second sealing assembly can prevent the lubricating liquid from being lost, so that the polished rod 35 can be fully lubricated and dry grinding of the polished rod 35 can be prevented.

[0073] After the middle box 3 and the lower packing box 4 are disassembled, the upper packing box 2, the middle box 3, the oil pressure sleeve 9 and the lubricating liquid filling assembly can be lifted upward as a whole, and the lower packing can be added to the lower packing box 4. There is no need to separately disassemble the middle box 3 and the lubricating liquid filling assembly. The lubricating liquid filling assembly fills the lubricating liquid with a certain pressure into the liquid inlet 11. The pressure-bearing capacity of the packing box is greater than that of an ordinary packing box.

[0074] The upper pressure cover 1 is tightened regularly, and the upper pressure cover 1 acts on the second sealing assembly through the compression spring 7 and the compression piston 6. The compression spring 7 can be an existing well-known pressure spring. In this way, the compression force of the second sealing assembly can be maintained after the upper pressure cover 1 is tightened. When the second sealing assembly is worn, it is subjected to downward pressure and can still wrap the polished rod 35 tightly to maintain a lasting seal on the polished rod 35.

[0075] The packing box is arranged into 3 sections (upper packing box 2, middle box 3, lower packing box 4). The upper packing box 2, middle box 3, lower packing box 4 can be independently disassembled and assembled, which is convenient for adding the first sealing component and also convenient for processing and manufacturing the packing box.

[0076] The anti-dry wear sealing method for the pumping wellhead can achieve continuous lubrication of the pumping wellhead seal, make the maintenance of the sealing component more convenient, and avoid the phenomenon of lubricating fluid leaking downward or upward. When the intermittent oil well is only discharging gas, it can avoid the phenomenon of the polished rod 35 becoming hot due to dry wear between the polished rod 35 and the packing, and oil leakage after the seal fails.

[0077] The above-mentioned pumping wellhead anti-dry wear sealing method can be further optimized and / or improved according to actual needs:

[0078] Embodiment 2: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown, step S4 specifically comprises: coaxially sleeveing ​​the copper wear-resistant sleeve 17 on the inner side of the lower part of the upper packing box 2 below the upper support ring platform 5; fixing the upper end of the oil pressure sleeve 9 having at least one oil hole 10 connected inside and outside at intervals on the outside together with the lower end of the upper packing box 2; and making the upper end of the oil pressure sleeve 9 and the lower end of the wear-resistant sleeve 17 contact each other.

[0079] The copper wear-resistant sleeve 17 can prevent the polished rod 35 and the upper packing box 2 from eccentric wear, reduce the wear of the polished rod 35, and prevent the polished rod 35 from contacting the rigid material inside the packing box and causing burrs or wear.

[0080] Embodiment 3: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown, step S5 specifically comprises: passing the lower end of the oil pressure sleeve 9 through the outside of the light rod 35 and placing it on the lower auxiliary sealing ring 37 or the upper end of the first sealing component at the top; fixing the lower end of the upper packing box 2 with the upper supporting ring platform 5 fixed on the inner side of the lower part and the upper end of the middle box 3 together; the inner wall of the upper packing box 2 above the upper supporting ring platform 5 is a conical surface with a larger upper part and a smaller lower part; a sealing ring groove with an opening upward is provided on the inner side of the upper end of the middle box 3; the first sealing member 16 is installed at the bottom of the sealing ring groove; the outer side of the lower part of the lower pressure cover 15 is screwed into the sealing ring groove and the lower end of the lower pressure cover 15 and the upper end of the first sealing member 16 are in contact with each other.

[0081] In order to facilitate the disassembly and assembly of the lower pressure cover 15, a disassembly and assembly handle is fixedly installed on the outer side of the upper end of the lower pressure cover 15. When the lower pressure cover 15 is rotated, the lower end of the lower pressure cover 15 and the lower inner wall of the sealing ring groove approach each other and squeeze the first sealing member 16. The first sealing member 16 is a well-known sealing gasket or sealing ring. The first sealing member 16 can improve the sealing between the upper packing box 2 and the middle box 3 to avoid oil and gas leakage. The setting of the lower pressure cover 15 makes it possible to adjust the tightness of the first sealing member 16, so that it is easy to replace the first sealing member 16 when it is damaged.

[0082] Embodiment 4: As an optimization of the above embodiment, as shown in the attached Figure 2 As shown, the lubricating liquid filling assembly in step S9 includes an oil tank 18, a piston 19, a screw rod 20 and a first plug 21. The oil tank 18 is in the shape of a cylinder with an open upper end and a closed lower end. The outer side of the lower end of the oil tank 18 is provided with a liquid outlet connected to the inside and outside. A first liquid inlet pipe 22 is fixedly connected between the liquid outlet and the liquid inlet 11. A first regulating valve 23 is installed on the first liquid inlet pipe 22. The upper end of the oil tank 18 is detachably fixedly provided with a first plug 21. The center of the first plug 21 is provided with a threaded hole that passes through from top to bottom. The outer side of the screw rod 20 is screwed into the threaded hole. The lower end of the screw rod 20 is provided with a threaded groove that opens downward. A Connecting bolt 24, the piston 19 is sleeved on the inner side of the oil tank 18 and has an upwardly opening mounting groove at the upper end, the lower end of the connecting bolt 24 is sleeved in the mounting groove, a sealing ring 25 is fixed to the outer side of the lower end of the piston 19, a small pressure cover 26 is screwed to the outer side of the upper end of the piston 19, a hanging ring 36 in contact with the upper end surface of the head of the connecting bolt 24 is fixed to the inner side of the upper end of the small pressure cover 26, a second sealing member 27 is installed between the lower end of the small pressure cover 26 and the upper end of the sealing ring 25, and then lubricating liquid is added to the oil tank 18 regularly (every seven days), and the screw 20 is rotated regularly to move the piston 19 downward and then the lubricating liquid is added to the middle box 3.

[0083] In order to facilitate the disassembly and assembly of the first plug 21 and the screw rod 20, a rotating handle is fixed on the outer side of the upper end of the screw rod 20 and the outer side of the upper end of the first plug 21, and the lubricating liquid is filled in the oil tank 18. After the screw rod 20 is rotated, the screw rod 20 drives the plunger to move downward, so that the lubricating liquid is injected into the middle box 3 through the first liquid inlet pipe, thereby lubricating the light rod 35 and the second sealing assembly, avoiding dry grinding between the light rod 35 and the second sealing assembly, thereby extending the service life of the second sealing assembly, and in order to avoid the small pressure cover 26 from rotating when tightening After that, the first seal 16 is squeezed and deformed too much, resulting in seal failure. A hanging ring 36 can be fixed on the inner side of the upper end of the small gland 26, so that the upper end of the piston 19 can limit the small gland 26 after contacting the lower end surface of the hanging ring 36. The hanging ring 36 is hung on the head of the connecting bolt 24. At the same time, the setting of the hanging ring 36 can flexibly rotate the screw rod 20 so that the head of the connecting bolt 24 can generate a pulling force on the small gland 26 and the piston 19 and then move upward. The setting of the small gland 26 also facilitates the disassembly and assembly of the first seal 16.

[0084] Butter (or thick oil) is injected into the oil tank 18 as a lubricant. The butter has strong adhesion, low fluidity, and low consumption rate. The butter has the ability to automatically adjust the consumption according to the temperature of the polished rod 35. The higher the temperature, the lower the viscosity, the stronger the fluidity, and the simple operation. It is consistent with the habit of applying butter to the polished rod 35 in the oil production operation area, and is suitable for most oil wells with intermittent oil production and occasional heating of the polished rod 35.

[0085] Embodiment 5: As another optimization of Embodiment 3, as shown in the attached Figure 3 As shown, the lubricating liquid filling assembly in step S9 includes a liquid storage tank 28, a first oil pipe coupling 29, a second oil pipe coupling 30, a second plug 31, a third plug 38 and a second liquid inlet pipe 32. The outer side of the upper part of the liquid storage tank 28 is fixedly connected with the first oil pipe coupling 29, and the upper end of the first oil pipe coupling 29 is fixedly installed with the second plug 31. The lower end of the liquid storage tank 28 is fixedly connected with a connecting short section 33, and the lower end of the connecting short section 33 is detachably fixedly installed with the second oil pipe coupling 30, and the lower end of the second oil pipe coupling 30 is detachably fixedly installed with the third plug 38. The second oil pipe coupling 30 is fixedly connected with the liquid inlet 11. The second liquid inlet pipe 32 is installed with a second regulating valve 34. After the second plug 31 is removed, the lubricating liquid is added to the liquid storage tank 28 and the second plug 31 is installed, and the lubricating liquid in the liquid storage tank 28 flows into the middle box 3.

[0086] The first oil pipe coupling 29 and the second oil pipe coupling 30 are both existing well-known oil pipe couplings. The second regulating valve 34 can close the second liquid inlet pipe 32 when replacing the second sealing assembly, thereby preventing the lubricating liquid from flowing into the middle box 3, facilitating the disassembly and assembly of the packing box and the replacement of the sealing assembly. The provision of the connecting short section 33 facilitates the standardized production of the liquid storage tank 28. The inner side of the lower end of the second oil pipe coupling 30 is threadedly connected to the outer side of the upper end of the third plug 38. The inner side of the upper end of the second oil pipe coupling 30 is threadedly connected to the connecting short section 33, which is convenient for installation at the well site and improves the disassembly and assembly efficiency of the liquid storage tank 28 and the middle box 3.

[0087] Crude oil (or water) is injected into the liquid storage tank 28 as a lubricant. The fluidity of crude oil is strong, and the lubricant keeps in contact with the polished rod 35, so the lubrication effect is good. It is suitable for extremely harsh oil wells where the polished rod 35 continues to be hot for a long time, the polished rod 35 shakes, and the surface of the polished rod 35 is rough.

[0088] On June 27, 2024, wells 7333 and 8269 were selected for testing. The polished rod of well 7333 was hot but did not swing or shake, and had burrs. The replacement cycle of the sealing component before the test was 7 days. The polished rod of well 8269 was hot, swung and shook, had pits and a rough surface, and the well was opened for 2 hours every day before the test.

[0089] Among them, the wellhead seal of Well 7333 was normal from June 27 to July 1. However, the well malfunctioned from July 2 onwards, with the bare rod becoming seriously hot and oil leakage from the upper gland 1 thread and other places being quite serious. The test was stopped on July 4 for pump inspection and maintenance.

[0090] Among them, Well 8269 was changed to intermittent pumping after the wellhead sealing test, with 1 hour on and 5 hours off, with a total of 4 hours of well opening every day. It was observed once a day from July 2. When the packing box of this well was loose, there was obvious oil leakage from the upper gland 1 thread and other places. Continuous tracking was carried out from 16:00 to 23:30 on July 2, and manual pumping was carried out from 21:15 to 23:15. The polished rod began to heat up 15 minutes after the well was started, and reached its peak in about 45 minutes. Under the condition of engine oil lubrication, the surface temperature of the polished rod 35 reached about 100°C (water vapor continued to evaporate from the surface of the polished rod). Under the premise that the sealing component was not tightened in the middle, the oil leakage distance of the upper gland 1 thread was about 20mm.

[0091] Among them, the compression spring and the upper pressure cover 1 were replaced on July 10 in Well 8269 and on July 18 in Well 7333. After the replacement of the compression spring and the upper pressure cover 1, the oil leakage phenomenon reappeared. The lubricating fluid filling assembly in Example 7 was replaced in Well 8269 on July 22, and the lubricating fluid filling assembly in Example 6 was replaced in Well 7333 on July 24.

[0092] In the past month, one second sealing assembly was added to Well 8269 on July 2 and July 17, and two second sealing assemblies were added to Well 7333 on July 2. The first sealing assemblies of the two wells have not been replaced yet. This shows that under the premise of ensuring lubrication, the consumption rate of the first sealing assembly is very low, and the first sealing assembly is consumed slower than the second sealing assembly. Lubrication can extend the service life of the sealing assembly.

[0093] The changes in the liquid level in the liquid storage tank 28 when the lubricating fluid was continuously added to the 8269 well were measured on July 11, 13, and 15 (the second regulating valve 34 was fully open), and the consumption rates of different lubricating fluids were obtained when the second regulating valve 34 was fully open. The measurement of the controlled lubricating fluid consumption rate was carried out from July 17 to 25.

[0094] The measurement data table of different lubricant consumption rates of 8269 wells (the second regulating valve 34 is fully open)

[0095] Measurement date Lubricating fluid Average consumption (mL / h) July 11 Engine Oil 69.44 July 13 Engine Oil 70.67 July 13 Tap water 58.86 July 15 crude 98.67

[0096] Lubricating fluid consumption change rate (control valve opening) measurement data table

[0097] Measurement date hashtag Lubricating fluid Ball valve opening Average consumption (mL / h) July 16 8269 crude 45° 31.33 July 18-19 7333 Engine Oil 48° 10.17 July 20-22 7333 Engine Oil 47° 7.08 July 22-23 7333 Engine Oil 46° 4.73 July 17-18 8269 Engine Oil 43° 10.53 July 18-20 8269 Engine Oil 42° 6.57 July 22-24 8269 Output fluid 43° 8.42

[0098] The amount and frequency of lubricant addition can be adjusted according to demand. Adding lubricant can assist in lubricating the sealing component. The compression spring 7 continuously presses the second sealing component so that the second sealing component is in a semi-dry and semi-wet state to ensure normal production of the oil well. The consumption rate of the lubricant can be adjusted by controlling the opening of the first regulating valve 23 or the opening of the second regulating valve 34. In extreme cases where the oil well does not produce oil for a long time, resulting in the smooth rod becoming hot, the smooth rod swinging, and the smooth rod surface being rough, the method of increasing the consumption of lubricant (the first regulating valve 23 is fully opened or the second regulating valve 34 is fully opened) is used to maintain normal production of the oil well.

[0099] The anti-dry wear sealing method of the pumping wellhead can effectively solve the oil leakage problem of intermittent oil wells. Under the condition of regular replenishment of lubricating fluid, as long as the gland 1 is tightened normally (the two test wells are tightened once every 1-5 days) and lubricating fluid is added (lubricant is added once every 3-15 days in the 8269 well), the continuous production of intermittent oil wells can be guaranteed.

[0100] In the anti-dry wear sealing method for the pumping wellhead, the first sealing component and the second sealing component are installed in the conical surface of the packing box, so that the sealing ring is only added but not replaced, which extends the service life of the sealing component and the sealing ring addition cycle. The second sealing component is added to the packing box 2 of the two test wells once every 15 days, and the first sealing component is added to the lower packing box 4 once every 90 days, which reduces the labor intensity at the same time.

[0101] Embodiment 6: As attached Figure 2 , 3 As shown, the anti-dry wear sealing packing box includes a lubricating liquid filling assembly, an upper gland 1, an upper packing box 2, a middle box 3, a lower packing box 4, an upper packing 14 and a lower packing. The upper gland 1, the upper packing box 2, the middle box 3 and the lower packing box 4 are screwed together in sequence from top to bottom. An upper support ring 5 is fixed to the inner side of the upper part of the upper packing box 2. An upper packing 14 is arranged on the upper end of the upper support ring 5. A pressing piston 6 is installed on the upper end of the upper packing 14. A pressing piston 6 is installed between the upper end of the pressing piston 6 and the inner side of the upper part of the upper gland 1. A compression spring 7 is provided, a lower supporting ring platform 8 is fixed to the inner side of the lower part of the lower packing box 4, a lower packing is installed on the upper end of the lower supporting ring platform 8, an oil pressure sleeve 9 is provided on the upper end of the lower packing box 4, at least one oil hole 10 communicating with the inside and outside is distributed at intervals on the outside of the oil pressure sleeve 9, the upper part of the oil pressure sleeve 9 is screwed together with the inner side of the lower part of the upper packing box 2, a liquid inlet 11 communicating with the inside and outside is provided on the outer side of the middle part of the middle box 3, and the liquid outlet of the lubricating liquid filling assembly is fixedly connected with the liquid inlet 11.

[0102] According to the needs, an outer ring platform is fixed to the outer side of the upper end of the clamping piston 6, and a limited inner ring platform is fixed to the inner side of the upper end of the upper pressure cover 1. The compression spring 7 is installed between the upper end of the outer ring platform and the lower end of the limited inner ring platform. In this way, the force-bearing area at both ends of the compression spring 7 can be increased. In order to avoid the failure of the compression spring 7 after the force is concentrated, the upper end of the outer side of the outer ring platform can also bulge upward to form a sleeve that is mounted on the outer side of the lower part of the compression spring 7, which can prevent the compression spring 7 from being offset and wearing against the light rod 35.

[0103] The upper gland 1 is tightened regularly, and the upper gland 1 acts on the upper packing 14 through the compression spring 7 and the compression piston 6, so that the compression force of the upper packing 14 can be maintained. When the upper packing 14 is worn, the compression spring 7 allows the upper packing 14 to still be covered on the outside of the aiming rod 35, maintaining a permanent seal of the aiming rod 35.

[0104] Lubricating liquid is regularly added to the lubricating liquid filling assembly. The lubricating liquid can be engine oil, transmission oil, butter, crude oil, etc. The lubricating liquid is injected into the liquid inlet 11 by the lubricating liquid filling assembly, and then the lubricating liquid passes through the oil hole 10 of the oil pressure sleeve 9 and evenly adheres to the outside of the polished rod 35, so that the polished rod 35 is lubricated. The arrangement of the upper packing 14 and the lower packing can prevent the lubricating liquid from being lost, so that the polished rod 35 can be fully lubricated and dry grinding of the polished rod 35 can be prevented.

[0105] Open the upper packing box 2 to add the lower packing into the lower packing box 4 without disassembling the middle box 3 and the lubricating liquid filling assembly, which effectively solves the problem that the lower packing in the lower packing box 4 is difficult to update. The lubricating liquid filling assembly fills the lubricating liquid into the liquid inlet 11 so that the lubricating liquid has a certain pressure. The pressure bearing capacity of the packing box is greater than that of an ordinary packing box. The packing box is arranged in 3 sections (upper packing box 2, middle box 3 and lower packing box 4), which makes it easy to add the upper packing 14 and the lower packing.

[0106] The wellhead sealing device can realize continuous lubrication of the pumping wellhead seal and more convenient packing maintenance, avoiding the phenomenon of lubricating fluid leaking downward or upward, and can ensure that the intermittent oil well does not leak oil after the smooth rod 35 and the packing are dry-ground, the smooth rod 35 becomes hot, and the seal fails when only air is discharged.

[0107] The oil pressure sleeve 9 can transmit the pressure of the upper packing box 2, thereby pressing the lower packing to ensure the sealing effect between the lower packing and the polished rod 35. The oil hole 10 of the oil pressure sleeve 9 can also filter impurities in the lubricating fluid to prevent the polished rod 35 from being scratched by impurities.

[0108] The above anti-dry wear sealing packing box can be further optimized and / or improved according to actual needs:

[0109] Embodiment 7: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown in Figures 4 and 5, the inner wall of the lower packing box 4 above the lower support ring platform 8 is a conical surface with a larger upper part and a smaller lower part. The lower packing includes a plurality of first sealing components stacked on the inner side of the upper support ring platform 5 from bottom to top. The first sealing component includes an upper sealing ring 12 and a lower sealing ring 13. The cross section of the upper sealing ring 12 is a right-angled trapezoid with a narrow inner part and a wide outer part. The cross section of the lower sealing ring 13 is a right-angled trapezoid with a wide inner part and a narrow outer part. The upper end face of the lower sealing ring 13 matches the lower end face of the upper sealing ring 12. The outer sides of the upper sealing ring 12 and the lower sealing ring 13 are provided with a cut of 20 to 45 degrees.

[0110] Or, attach Figure 6 , 7 As shown, the lower packing includes a lower auxiliary sealing ring 37 and a plurality of first sealing components stacked sequentially from bottom to top on the inner side of the upper support ring platform 5, the first sealing component includes an upper sealing ring 12 and a lower sealing ring 13, the cross section of the upper sealing ring 12 is a right-angled trapezoid with a narrow inner side and a wide outer side, the cross section of the lower sealing ring 13 is a right-angled trapezoid with a wide inner side and a narrow outer side, and the upper end surface of the lower sealing ring 13 matches the lower end surface of the upper sealing ring 12, the upper end of the upper sealing ring 12 is installed with a lower auxiliary sealing ring 37, the cross section of the lower auxiliary sealing ring 37 is rectangular, and the outer sides of the upper sealing ring 12, the lower sealing ring 13 and the lower auxiliary sealing ring 37 are all provided with a 20 to 45 degree cut;

[0111] The inner wall of the upper packing box 2 corresponding to the position above the upper support ring platform 5 is a conical surface with a larger upper portion and a smaller lower portion. The upper packing 14 has the same structure as the lower packing and is installed on the upper end of the upper support ring platform 5 .

[0112] The outer sides of the upper sealing ring 12 and the lower sealing ring 13 are both provided with a cutout of 20 to 45 degrees, that is, the angle between the cutout and the horizontal plane is 20 to 45 degrees, and the inner wall of the upper packing box 2 corresponding to the upper support ring platform 5 is a conical surface with a larger upper part and a smaller lower part. The upper packing box 2 and the upper support ring platform 5 can be arranged as one piece, or the conical sleeve of the conical tube can be fixed together with the inner side of the upper packing box 2 by a plurality of connecting screws distributed along the circumference to form the lower support ring platform 8. The conical sleeve can be one piece or two symmetrical semi-conical sleeves, so that the sealing surface can always align with the upper packing. 14 and the lower packing generate a force. When the upper packing 14 and the lower packing are worn, the upper packing 14 moves downward under the action of the compression spring 7 and contacts with the polished rod 35 in a sealing manner, thereby ensuring the sealing effect between the upper packing 14 and the polished rod 35. Because the inclination angle of the polished rod 35 is small, the lateral component of the suspension point load is small. Under normal circumstances, the lateral force of the eccentric wear of the polished rod 35 on the packing is not large. In this way, the upper packing 14 and the lower packing can have a straightening effect on the polished rod 35, and it is possible to add new packing without replacing the old packing, further reducing the difficulty of maintenance.

[0113] The taper of the inner wall of the upper packing box 2 corresponding to the position above the upper supporting ring platform 5 and the inner wall of the lower packing box 4 above the lower supporting ring platform 8 can be set to the same, and the middle box 3 and the lower packing box 4 are screwed together, so that the position of the conical inner wall of the lower packing box 4 above the lower supporting ring platform 8 is relatively shallow, and the cutting force position of the tool is shallow when processing the inner wall of the lower packing box 4 above the lower supporting ring platform 8, which is convenient for processing the inner wall of the lower packing box 4 above the lower supporting ring platform 8.

[0114] A lower auxiliary sealing ring 37 is placed on the upper end of the upper sealing ring 12 at the top. The cross-section of the lower auxiliary sealing ring 37 is rectangular. A 20 to 45 degree cut is provided on the outer side of the lower auxiliary sealing ring 37. The thickness of the first sealing component can be twice the thickness of the lower auxiliary sealing ring 37. After stacking several first sealing components from bottom to top on the upper end of the lower support ring platform 8, another lower auxiliary sealing ring 37 is placed. This can avoid the phenomenon that the thickness of several first sealing components is too large or too small when they are stacked from bottom to top on the upper end of the lower support ring platform 8.

[0115] Embodiment 7: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown, the taper of the inner wall of the lower packing box 4 above the lower supporting ring platform 8 is 1:7 to 1:1.

[0116] The taper of the inner wall of the lower packing box 4 above the lower supporting ring platform 8 is 1:7 to 1:1, the taper of the conical surface of the upper packing box 2 is also 1:7 to 1:1, the distance between the upper end surface of the upper pressure cover 1 and the lower end surface of the lower packing box 4 is less than 450mm, the height of several first sealing assemblies and the height of several second sealing assemblies are both 100mm, the height of the cylindrical section is 65mm, the height of the conical section is 35mm, and the compression distance between several first sealing assemblies and several second sealing assemblies is 35 to 40mm.

[0117] The conical surfaces of the upper packing box 2 and the lower packing box 4 can exert a force on the first sealing assembly and the second sealing assembly at all times. When the first sealing assembly and the second sealing assembly are worn, the second sealing assembly moves downward under the action of the compression spring 7 and comes into sealing contact with the light rod 35, thereby ensuring the sealing effect between the second sealing assembly and the light rod 35. Because the inclination angle of the light rod 35 is small and the lateral component of the suspension point load is small, under normal circumstances, the lateral force of the eccentric wear of the light rod 35 on the sealing assembly is not large, so the first sealing assembly and the second sealing assembly in the conical surface can have a straightening effect on the light rod 35.

[0118] The setting of the conical surface can also realize that only new sealing components or auxiliary sealing rings are added to the upper packing box 2 and the lower packing box 4, without replacing the old sealing components (packing), further reducing the difficulty of maintenance, and preventing the lubricant from leaking downward or upward, ensuring that the intermittent oil well does not leak oil after the polished rod 35 and the sealing material are dry-ground, the polished rod 35 is hot, and the seal fails when only gas is discharged. The combination of two-stage sealing and middle lubrication can fully lubricate the polished rod 35, avoid the loss of lubricating fluid during single-stage sealing, prevent the packing from dry-grounding for a long time, and prevent the surface temperature of the polished rod 35 from being too high and blue, and quickly burn out the packing.

[0119] Embodiment 8: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown in , 4, 5, 6, and 7, the central axis of the inner ring surface of the upper sealing ring 12 is coaxial with the central axis of the outer ring surface or is provided with an eccentricity, and the central axis of the inner ring surface of the lower sealing ring 13 of each first sealing assembly is collinear with the central axis of the inner ring surface of the upper sealing ring 12.

[0120] In this embodiment, the material of the upper sealing ring 12 and the material of the lower sealing ring 13 are the same as the material of the transmission belt of the pulley of the pumping unit (6LC-5000Q / LYX0002-2009). The transmission belt is a consumable part of the wellhead equipment. A large number of waste transmission belts can be used to make the upper sealing ring 12 and the lower sealing ring 13, which can reduce the replacement cost of the sealing assembly. In addition, the material of the transmission belt can extend the wear resistance of the first sealing assembly and the second sealing assembly, and extend the replacement cycle. At the same time, the upper sealing ring 12 and the lower sealing ring 13 can be tightly wrapped around the outer side of the light rod 35 after installation, reducing the difficulty of installation.

[0121] The material of the transmission belt has both wear resistance and sealing properties. The material of the transmission belt is used in the sealing component, which can greatly reduce the risk of oil leakage. Compared with the graphite rubber packing, the material of the transmission belt is much more wear-resistant and high-temperature resistant. In the intermittent oil well, the polished rod 35 is prone to lose lubrication, resulting in the polished rod 35 getting hot and dry. The combination of the first sealing component of the transmission belt material and the lubricating liquid can extend the cycle of replacing the sealing component of the belt material.

[0122] The cross-sections of the upper sealing ring 12 and the lower sealing ring 13 are both trapezoidal, and the upper end surface of the upper sealing ring 12 and the lower end surface of the lower sealing ring 13 are both horizontal planes. The taper of the lower end surface of the upper sealing ring 12 is the same as the taper of the upper end surface of the upper sealing ring 12. In this way, the paired upper sealing rings 12 and lower sealing rings 13 are stacked on each other and used alternately. When the upper and lower ends of the first sealing component and the second sealing component are squeezed, the outer sides of the first sealing component and the second sealing component can expand outward. When the upper and lower ends of the first sealing component and the second sealing component are no longer squeezed, the outer sides of the first sealing component and the second sealing component shrink and then return to their original state, thereby realizing multi-stage sealing, which can improve the sealing effect between the sealing component and the light rod 35.

[0123] The height of the upper sealing ring 12 and the lower sealing ring 13 are both 15 mm, and the height of the first sealing assembly of two pieces stacked together is 28 mm. The central axis of the inner ring surface of the upper sealing ring 12, the lower sealing ring 13 and the lower auxiliary sealing ring 37 and the central axis of the outer ring surface are provided with an eccentricity, and the eccentricity can be 1 mm. In this way, it is more convenient to add the upper sealing ring 12 and the lower sealing ring 13 to the packing box with misaligned light rod 35.

[0124] Embodiment 9: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown, a sealing ring groove is provided on the inner side of the upper end of the middle box 3, a lower pressure cover 15 is screwed into the sealing ring groove, and a first sealing member 16 is installed between the lower end of the lower pressure cover 15 and the inner side of the lower part of the sealing ring groove.

[0125] In order to facilitate the disassembly and assembly of the lower pressure cover 15, a disassembly and assembly handle is fixedly installed on the outer side of the upper end of the lower pressure cover 15. When the lower pressure cover 15 is rotated, the lower end of the lower pressure cover 15 and the lower inner wall of the sealing ring groove approach each other and squeeze the first sealing member 16. The first sealing member 16 is an existing well-known sealing gasket or sealing ring. In this way, the first sealing member 16 can improve the sealing between the upper packing box 2 and the middle box 3 to avoid oil and gas leakage.

[0126] Embodiment 10: As an optimization of the above embodiment, as shown in the attached Figure 2 , 3 As shown, a copper wear-resistant sleeve 17 sleeved in the upper packing box 2 is provided between the lower end of the upper support ring platform 5 and the upper end of the oil pressure sleeve 9.

[0127] The material of the wear-resistant sleeve 17 is copper which is known in the prior art. The copper wear-resistant sleeve 17 can reduce the wear of the polished rod 35 and can also prevent the polished rod 35 from contacting the inner side of the packing box and causing burrs or wear.

[0128] Embodiment 11: As an optimization of the above embodiment, as shown in the attached Figure 2 As shown, the lubricating liquid filling assembly includes an oil tank 18, a piston 19, a screw rod 20 and a first plug 21. The oil tank 18 is in the shape of a cylinder with an open upper end and a closed lower end. The outer side of the lower end of the oil tank 18 is provided with an outlet connected to the inside and outside. A first liquid inlet pipe 22 is fixedly connected between the liquid outlet and the liquid inlet 11. A first regulating valve 23 is installed on the first liquid inlet pipe 22. The upper end of the oil tank 18 is detachably fixedly provided with a first plug 21. The center of the first plug 21 is provided with a threaded hole that runs through from top to bottom. The outer side of the screw rod 20 is screwed into the threaded hole. The screw rod 20 is screwed into the threaded hole. A threaded groove opening downward is provided at the lower end of 20, a connecting bolt 24 is screwed in the threaded groove, the piston 19 is sleeved on the inner side of the oil tank 18 and an installation groove opening upward is provided at the upper end, the lower end of the connecting bolt 24 is sleeved in the installation groove, a sealing ring 25 is fixed to the outer side of the lower end of the piston 19, a small pressure cover 26 is screwed to the outer side of the upper end of the piston 19, a hanging ring 36 in contact with the upper end surface of the head of the connecting bolt 24 is fixed to the inner side of the upper end of the small pressure cover 26, and a second sealing member 27 is installed between the lower end of the small pressure cover 26 and the upper end of the sealing ring 25.

[0129] In order to facilitate the disassembly and assembly of the first plug 21 and the screw rod 20, a rotating handle is fixed on the outer side of the upper end of the screw rod 20 and the outer side of the upper end of the first plug 21, and the lubricating liquid is filled in the oil tank 18. After the screw rod 20 is rotated, the screw rod 20 drives the piston 19 to move downward, so that the lubricating liquid is injected into the middle box 3 through the first liquid inlet pipe 22, which can lubricate the polished rod 35 and the lower packing, avoid dry grinding between the polished rod 35 and the lower packing, thereby extending the service life of the lower packing.

[0130] The second sealing member 27 is a sealing gasket or sealing ring known in the prior art, and the first regulating valve 23 is a regulating valve known in the prior art, such as a 1500Lb three-piece ball valve. In order to prevent the small gland 26 from rotating when tightening, which may cause excessive extrusion deformation of the first sealing member 16 and lead to sealing failure, a hanging ring 36 may be fixed on the inner side of the upper end of the small gland 26, so that the upper end of the piston 19 can limit the small gland 26 after contacting the lower end surface of the hanging ring 36. The hanging ring 36 is hung on the head of the connecting bolt 24. At the same time, the setting of the hanging ring 36 can flexibly rotate the screw rod 20 so that the head of the connecting bolt 24 can generate a pulling force on the small gland 26 and the piston 19 and then move upward. The setting of the small gland 26 also facilitates the disassembly and assembly of the first sealing member 16.

[0131] Embodiment 12: As an optimization of the above embodiment, as shown in the attached Figure 3 As shown, the lubricating fluid filling assembly includes a liquid storage tank 28, a first oil pipe coupling 29, a second oil pipe coupling 30, a second plug 31, a third plug 38 and a second liquid inlet pipe 32. The outer side of the upper part of the liquid storage tank 28 is fixedly connected with the first oil pipe coupling 29, and the upper end of the first oil pipe coupling 29 is fixedly installed with the second plug 31. The lower end of the liquid storage tank 28 is fixedly connected with a connecting short section 33, and the lower end of the connecting short section 33 is detachably fixedly installed with the second oil pipe coupling 30, and the lower end of the second oil pipe coupling 30 is detachably fixedly installed with the third plug 38. The second oil pipe coupling 30 is fixedly connected with the second liquid inlet pipe 32 between the second oil pipe coupling 30 and the liquid inlet 11, and the second liquid inlet pipe 32 is installed with a second regulating valve 34.

[0132] The first oil pipe coupling 29 and the second oil pipe coupling 30 are both existing well-known oil pipe couplings, and the second regulating valve 34 is an existing well-known regulating valve, such as a 1500Lb three-piece ball valve. The second regulating valve 34 can close the second liquid inlet pipe 32 when replacing the lower packing, thereby preventing the lubricating liquid from flowing into the middle box 3, and facilitating the disassembly and assembly of the packing box and the replacement of the packing. The inner side of the upper end of the first oil pipe coupling 29 is threadedly connected with the outer side of the lower end of the second plug 31, and a disassembly handle is fixed to the outer side of the upper end of the second plug 31. By setting the second plug 31, leakage of the lubricating liquid in the liquid storage tank 28 can be avoided, and it is also convenient to add lubricating liquid into the liquid storage tank 28. The setting of the connecting short section 33 is convenient for the liquid storage tank 28. The second oil pipe coupling 30 is made in a standardized manner, the inner side of the lower end of the second oil pipe coupling 30 is threadedly connected with the outer side of the upper end of the third plug 38, and the inner side of the upper end of the second oil pipe coupling 30 is threadedly connected with a connecting short section 33, which is convenient for installation at the well site and improves the disassembly and assembly efficiency between the liquid storage tank 28 and the middle box 3. The second liquid inlet pipeline 32 includes two connecting short tubes, the outer side of the left end of the left connecting short tube is threadedly connected to the liquid inlet, the outer side of the right end of the left connecting short tube is threadedly connected to the inner side of the left end of the second regulating valve 34, and the inner side of the right end of the second regulating valve 34 is threadedly connected to the outer side of the left end of the right connecting short tube, so that it is convenient to adjust the position of the handle of the second regulating valve 34, and the right end of the right connecting short tube is welded to the second oil pipe coupling 30.

[0133] The above technical features respectively constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for sealing an oil wellhead against dry wear, characterized in that: The steps include: S1, the lower end of the lower packing box with the lower support ring fixed on the inner side of the lower part passes through the outer side of the polished rod and is fixedly installed together with the upper end of the wellhead equipment, and the inner wall of the lower packing box above the lower support ring is a conical surface with a larger upper part and a smaller lower part; S2, install the lower packing in the annulus between the inner side of the lower packing box and the outer side of the polished rod, including: Stacking a plurality of first sealing assemblies from bottom to top in sequence on the upper end of the lower support ring platform, the first sealing assemblies comprising an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring being a trapezoid with a narrow inner side and a wide outer side; the cross section of the lower sealing ring being a trapezoid with a wide inner side and a narrow outer side, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, and the outer sides of the upper sealing ring and the lower sealing ring are both provided with a cut of 20 to 45 degrees; Alternatively, a lower auxiliary sealing ring is placed on the upper end of the upper sealing ring at the top, the cross section of the lower auxiliary sealing ring is rectangular, and a cut of 20 to 45 degrees is provided on the outer side of the lower auxiliary sealing ring; S3, the lower end of the middle box with a liquid inlet connected to the inside and outside is passed through the outside of the polished rod and then screwed together with the upper end of the lower packing box; S4, screwing the outer side of the upper part of the oil pressure sleeve having at least one oil hole communicating with the inner and outer sides at intervals on the outer side together with the inner side of the lower end of the upper packing box; S5, pass the lower end of the oil pressure sleeve through the outside of the polished rod and place it on the lower auxiliary sealing ring or the upper end of the first sealing assembly at the top, and fix the lower end of the upper packing box with the upper support ring platform fixed on the inner side of the lower part and the upper end of the middle box together, the inner wall of the upper packing box above the upper support ring platform is a conical surface with a larger upper part and a smaller lower part, and adjust the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod; S6, install the packing, including: A plurality of second sealing assemblies are sequentially mounted in the annular space between the inner annular surface of the upper support ring platform and the outer side of the polished rod from bottom to top, wherein the second sealing assemblies have the same structure as the first sealing assemblies; Alternatively, an upper auxiliary sealing ring is placed on the upper end of the uppermost second sealing assembly, and the upper auxiliary sealing ring has the same structure as the lower auxiliary sealing ring; S7, passing the pressing piston and the compression spring through the outer side of the polished rod in sequence and stacking them on the upper auxiliary sealing ring or the upper end of the second sealing assembly at the top; S8, passing the lower part of the upper gland through the outer side of the polished rod and screwing it together with the upper part of the upper packing box, adjusting the number of rotations of the upper gland so that the second sealing assembly is in sealing contact with the outer side of the polished rod; S9, the liquid outlet and the liquid inlet of the lubricating liquid filling assembly are fixedly connected, and the lubricating liquid is filled into the middle box through the lubricating liquid filling assembly; The lubricating liquid filling assembly comprises an oil tank, a piston, a screw rod and a first plug, the oil tank is in the shape of a cylinder with an open upper end and a closed lower end, the outer side of the lower end of the oil tank is provided with a liquid outlet connected inside and outside, a first liquid inlet pipe is fixedly connected between the liquid outlet and the liquid inlet, a first regulating valve is installed on the first liquid inlet pipe, the upper end of the oil tank is detachably and fixedly installed with a first plug, a threaded hole that passes through from top to bottom is provided in the center of the first plug, the outer side of the screw rod is screwed into the threaded hole, the lower end of the screw rod is provided with a threaded groove opening downward, a connecting bolt is screwed in the threaded groove, the piston is sleeved on the inner side of the oil tank and the upper end is provided with a mounting groove opening upward, the lower end of the connecting bolt is sleeved in the mounting groove, a sealing ring platform is fixed on the outer side of the lower end of the piston, a small pressure cover is screwed on the outer side of the upper end of the piston, a hanging ring platform in contact with the upper end surface of the head of the connecting bolt is fixed on the inner side of the upper end of the small pressure cover, and a second sealing member is installed between the lower end of the small pressure cover and the upper end of the sealing ring platform.

2. The method for sealing an oil wellhead against dry wear according to claim 1, characterized in that Step S4 specifically includes: coaxially sleeveing ​​the copper wear-resistant sleeve on the inner side of the lower part of the upper packing box below the upper support ring, fixing the upper end of the oil pressure sleeve with at least one oil hole connected inside and outside distributed on the outside and the lower end of the upper packing box together, and making the upper end of the oil pressure sleeve and the lower end of the wear-resistant sleeve contact each other.

3. The method for sealing an oil wellhead against dry wear according to claim 1 or 2, characterized in that Step S5 specifically comprises the following steps: passing the lower end of the oil pressure sleeve through the outside of the polished rod and placing it on the upper end of the lower auxiliary sealing ring or the upper end of the first sealing assembly at the top; screwing the outer side of the lower end of the upper packing box with the upper supporting ring platform fixed on the inner side of the lower part and the inner side of the upper part of the middle box together; the inner wall of the upper packing box above the upper supporting ring platform is a conical surface with a larger upper part and a smaller lower part; adjusting the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod; providing a sealing ring groove with an opening upward on the inner side of the upper end of the middle box; installing a first sealing member at the bottom of the sealing ring groove; screwing the outer side of the lower part of the lower cover into the sealing ring groove so that the lower end of the lower cover and the upper end of the first sealing member are in contact with each other.

4. A method for sealing an oil wellhead against dry wear, characterized in that: The steps include: S1, the lower end of the lower packing box with the lower support ring fixed on the inner side of the lower part passes through the outer side of the polished rod and is fixedly installed together with the upper end of the wellhead equipment, and the inner wall of the lower packing box above the lower support ring is a conical surface with a larger upper part and a smaller lower part; S2, install the lower packing in the annulus between the inner side of the lower packing box and the outer side of the polished rod, including: Stacking a plurality of first sealing assemblies from bottom to top in sequence on the upper end of the lower support ring platform, the first sealing assemblies comprising an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring being a trapezoid with a narrow inner side and a wide outer side; the cross section of the lower sealing ring being a trapezoid with a wide inner side and a narrow outer side, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, and the outer sides of the upper sealing ring and the lower sealing ring are both provided with a cut of 20 to 45 degrees; Alternatively, a lower auxiliary sealing ring is placed on the upper end of the upper sealing ring at the top, the cross section of the lower auxiliary sealing ring is rectangular, and a cut of 20 to 45 degrees is provided on the outer side of the lower auxiliary sealing ring; S3, the lower end of the middle box with a liquid inlet connected to the inside and outside is passed through the outside of the polished rod and then screwed together with the upper end of the lower packing box; S4, screwing the outer side of the upper part of the oil pressure sleeve having at least one oil hole communicating with the inner and outer sides at intervals on the outer side together with the inner side of the lower end of the upper packing box; S5, pass the lower end of the oil pressure sleeve through the outside of the polished rod and place it on the lower auxiliary sealing ring or the upper end of the first sealing assembly at the top, and fix the lower end of the upper packing box with the upper support ring platform fixed on the inner side of the lower part and the upper end of the middle box together, the inner wall of the upper packing box above the upper support ring platform is a conical surface with a larger upper part and a smaller lower part, and adjust the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod; S6, install the packing, including: A plurality of second sealing assemblies are sequentially mounted in the annular space between the inner annular surface of the upper support ring platform and the outer side of the polished rod from bottom to top, wherein the second sealing assemblies have the same structure as the first sealing assemblies; Alternatively, an upper auxiliary sealing ring is placed on the upper end of the uppermost second sealing assembly, and the upper auxiliary sealing ring has the same structure as the lower auxiliary sealing ring; S7, passing the pressing piston and the compression spring through the outer side of the polished rod in sequence and stacking them on the upper auxiliary sealing ring or the upper end of the second sealing assembly at the top; S8, passing the lower part of the upper gland through the outer side of the polished rod and screwing it together with the upper part of the upper packing box, adjusting the number of rotations of the upper gland so that the second sealing assembly is in sealing contact with the outer side of the polished rod; S9, the liquid outlet and the liquid inlet of the lubricating liquid filling assembly are fixedly connected, and the lubricating liquid is filled into the middle box through the lubricating liquid filling assembly; The lubricating fluid filling assembly includes a liquid storage tank, a first oil pipe coupling, a second oil pipe coupling, a second plug, a third plug and a second liquid inlet pipe. The outer side of the upper portion of the liquid storage tank is fixedly connected to the first oil pipe coupling, the upper end of the first oil pipe coupling is fixedly installed with the second plug, the lower end of the liquid storage tank is fixedly connected to a connecting short section, the lower end of the connecting short section is detachably fixedly installed with a second oil pipe coupling, the lower end of the second oil pipe coupling is detachably fixedly installed with a third plug, a second liquid inlet pipe is fixedly connected between the second oil pipe coupling and the liquid inlet, and a second regulating valve is installed on the second liquid inlet pipe.

5. The method for sealing an oil wellhead against dry wear according to claim 4, characterized in that Step S4 specifically includes: coaxially sleeveing ​​the copper wear-resistant sleeve on the inner side of the lower part of the upper packing box below the upper support ring, fixing the upper end of the oil pressure sleeve with at least one oil hole connected inside and outside distributed on the outside and the lower end of the upper packing box together, and making the upper end of the oil pressure sleeve and the lower end of the wear-resistant sleeve contact each other.

6. The method for sealing an oil wellhead against dry wear according to claim 4 or 5, characterized in that Step S5 specifically comprises the following steps: passing the lower end of the oil pressure sleeve through the outside of the polished rod and placing it on the upper end of the lower auxiliary sealing ring or the upper end of the first sealing assembly at the top; screwing the outer side of the lower end of the upper packing box with the upper supporting ring platform fixed on the inner side of the lower part and the inner side of the upper part of the middle box together; the inner wall of the upper packing box above the upper supporting ring platform is a conical surface with a larger upper part and a smaller lower part; adjusting the number of rotations of the upper packing box so that the first sealing assembly is in sealing contact with the outer side of the polished rod; providing a sealing ring groove with an opening upward on the inner side of the upper end of the middle box; installing a first sealing member at the bottom of the sealing ring groove; screwing the outer side of the lower part of the lower cover into the sealing ring groove so that the lower end of the lower cover and the upper end of the first sealing member are in contact with each other.

7. An anti-dry wear sealing packing box used in the oil pumping well head anti-dry wear sealing method according to any one of claims 1 to 6, characterized in that The cam is provided with a plurality of support holes, the support holes being arranged on the upper and lower parts of the cam, and the support holes being arranged on the upper and lower parts of the cam.

8. The anti-dry wear sealing packing box according to claim 7, characterized in that The inner wall of the lower packing box above the lower support ring platform is a conical surface with a larger upper part and a smaller lower part. The lower packing includes a plurality of first sealing components stacked sequentially from bottom to top on the inner side of the upper support ring platform. The first sealing component includes an upper sealing ring and a lower sealing ring. The cross section of the upper sealing ring is a right-angled trapezoid with a narrow inner part and a wide outer part. The cross section of the lower sealing ring is a right-angled trapezoid with a wide inner part and a narrow outer part. The upper end face of the lower sealing ring matches the lower end face of the upper sealing ring. The outer sides of the upper sealing ring and the lower sealing ring are both provided with a cut of 20 to 45 degrees. Alternatively, the lower packing includes a lower auxiliary sealing ring and a plurality of first sealing assemblies stacked sequentially from bottom to top on the inner side of the upper support ring platform, the first sealing assembly includes an upper sealing ring and a lower sealing ring, the cross section of the upper sealing ring is a right-angled trapezoid with a narrow inner side and a wide outer side, the cross section of the lower sealing ring is a right-angled trapezoid with a wide inner side and a narrow outer side, and the upper end face of the lower sealing ring matches the lower end face of the upper sealing ring, a lower auxiliary sealing ring is installed on the upper end of the uppermost upper sealing ring, the cross section of the lower auxiliary sealing ring is a rectangle, and the outer sides of the upper sealing ring, the lower sealing ring and the lower auxiliary sealing ring are all provided with a cut of 20 to 45 degrees; The inner wall of the upper packing box corresponding to the position above the upper supporting ring platform is a conical surface with a larger upper portion and a smaller lower portion. The upper packing has the same structure as the lower packing and is installed on the upper end of the upper supporting ring platform.

9. The anti-dry wear sealing packing box according to claim 8, characterized in that The central axis of the inner ring surface of the upper sealing ring is coaxial with the central axis of the outer ring surface or is provided with an eccentricity, and the central axis of the inner ring surface of the lower sealing ring of each first sealing assembly is collinear with the central axis of the inner ring surface of the upper sealing ring; Or / and, the taper of the inner wall of the lower packing box above the lower support ring is 1:7 to 1:1; Or / and, a sealing ring groove is provided on the inner side of the upper end of the middle box, a lower gland is screwed in the sealing ring groove, and a first sealing member is installed between the lower end of the lower gland and the inner side of the lower part of the sealing ring groove; Or / and, a copper wear-resistant sleeve sleeved in the upper packing box is provided between the lower end of the upper support ring platform and the upper end of the oil pressure sleeve.

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