A pumping unit light rod well mouth sealing method and pumping unit sealing packing

Abstract

The present application relates to a kind of pumping unit polish rod wellhead sealing method, pumping unit sealing packing, belong to oilfield production engineering technical field.The polish rod wellhead sealing method of pumping unit of the present application, comprising the following steps: take annular washer and put into wellhead packing box cavity bottom on polish rod, then in packing box cavity alternately put into rubber strip and semi-solid lubricant, until to fill up packing seal box, then take annular washer and put into polish rod, install good gland and packing pressure cap, tighten;When putting into rubber strip, make rubber strip surround polish rod and place and in packing box cavity fill up a layer.The polish rod sealing method of pumping unit of the present application, completely solve the problem of difficult to add and take when replacing packing packing, reduce the labor intensity of post worker, especially applicable to the oil well of on-site polish rod not centering, and sealing effect is good, can effectively manage packing running, leaking and leaking phenomenon, reduce wear and tear, extend the use cycle of packing, realize the purpose of cost reduction and efficiency increase and energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to a method for sealing the polished rod wellhead of a pumping unit and a sealing packing for the pumping unit, belonging to the field of oilfield production engineering technology. Background Technology

[0002] The main production equipment in oil production is rod-operated pumping equipment. The wellhead polished rod sealing device is an essential component of rod-operated pumping equipment, and its performance directly affects the working quality of the surface pumping unit and its downhole equipment, as well as the environmental quality. The packing box, as a sealing device for the polished rod of the pumping unit, is filled with sealing packing material that allows the polished rod to pass through, sealing the annular space between the tubing and the polished rod.

[0003] However, at oil production sites, factors such as foundation subsidence, overturned workpieces, pumping unit installation deviations, and wellbore and wellhead deformation can easily cause the polished rod to become misaligned, making it difficult to replace O-rings and significantly shortening their service life. This is especially true for wells in later stages of production, where polished rod corrosion is severe, further increasing the difficulty of O-ring replacement and resulting in poor sealing, frequent leaks, and contamination of wellhead equipment. This poses challenges to safe production and increases the workload for workers. Furthermore, the discarded packing is often abandoned and cannot be recycled, and similarly, old pumping unit belts are not recycled, contributing to environmental pollution to varying degrees.

[0004] In the prior art, Chinese patent document CN 106246128A discloses an injection-type packing for sealing the polished rod at the wellhead of a pumping unit. This packing is prepared by mixing and heating 20-40 parts of polytetrafluoroethylene, 10-35 parts of aramid fiber, 10-35 parts of molybdenum disulfide, 8-30 parts of silicone oil, 5-20 parts of tungsten disulfide, 1-10 parts of silicone grease, and 1-10 parts of paraffin wax until homogeneous. The stirring temperature is controlled at 105-195℃, and the stirring time is 1.5-15 hours. When using this packing for sealing, it can be conveniently and quickly added to the sealing cavity through the injection port using an injection tool without stopping the machine, eliminating the need for frequent machine shutdowns to replace packing, thus reducing labor intensity. However, it is only suitable for sealing equipment with an injection port and not for traditional sealing equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a method for sealing the polished rod wellhead of a pumping unit without altering the structure of the sealing equipment, which can completely solve the problem of difficulty in adding and removing packing when replacing packing.

[0006] The present invention also provides a sealing packing for an oil pumping unit.

[0007] To achieve the above objectives, the technical solution adopted by the oil pumping unit polished rod wellhead sealing method of the present invention is as follows:

[0008] A method for sealing the wellhead of a pumping unit's polished rod includes the following steps: placing an annular washer on the polished rod and inserting it into the bottom of the wellhead packing box cavity; then alternately placing rubber strips and semi-solid lubricant into the packing box cavity until it is full; then placing the annular washer on the polished rod, installing the gland and packing cap, and tightening them; when placing the rubber strips, ensuring that the rubber strips surround the polished rod and form a layer that completely covers the packing box cavity.

[0009] The oil wellhead sealing method for the polished rod of this invention breaks away from the original packing sealing method, completely solving the problem of difficult addition and removal of packing material during replacement, and reducing the labor intensity of workers. Especially for oil wells where the polished rod is not centered, the sealing method of this invention is simple and convenient to operate. Furthermore, the sealing method of this invention has a good sealing effect, effectively preventing packing leakage, and also reduces wear, extends the service life of the packing, and achieves the goals of cost reduction, efficiency improvement, energy conservation, and environmental protection.

[0010] Furthermore, the annular washer is an annular dovetail-type plug-in washer. Even further, the annular dovetail-type plug-in washer is formed by connecting two or more fan-shaped annular plug-in pieces end-to-end; the first end of each fan-shaped annular plug-in piece is a dovetail plug, and the last end is a dovetail slot that matches the dovetail plug at the first end. The width of the annular washer matches the annular space between the guide rod and the packing box.

[0011] Furthermore, the semi-solid lubricant is composed of the following components in weight fractions: 2.5-5 parts of lithium molybdenum disulfide grease, 5-15 parts of graphite powder, 10-20 parts of lead powder, and 5-10 parts of bentonite. In this semi-solid lubricant, the lithium molybdenum disulfide grease provides lubrication, wear resistance, and corrosion protection; the graphite powder is a lubricating material with lubricating properties; the lead powder provides lubrication and plasticity, which helps the semi-solid lubricant and rubber strips to form within the packing box cavity; and the organic bentonite is a stabilizer with filling, stabilizing, and adsorption properties.

[0012] Furthermore, the semi-solid lubricant is obtained by uniformly mixing molybdenum disulfide, graphite powder, lead powder, and bentonite at room temperature. The molybdenum disulfide lithium-based grease is prepared by thickening mineral oil with lithium hydroxy fatty acid soap and adding additives such as molybdenum disulfide.

[0013] In order to integrate the rubber strip and the semi-solid lubricant into a more wear-resistant solid material, the mass ratio of the rubber strip to the semi-solid lubricant is further 40-65:22.5-60.

[0014] Furthermore, the graphite powder has an average particle size of 15–20 μm, for example, 7–20 μm. The lead powder has an average particle size of 26–30 μm. The bentonite has an average particle size of 30–50 μm.

[0015] Furthermore, the bentonite is a base bentonite.

[0016] Furthermore, to prevent the rubber strip from being carried downhole with the polished rod, the diameter of the rubber strip is preferably 5-7 mm. To better integrate the rubber strip with the semi-solid lubricant and facilitate its insertion into the packing box cavity, the rubber strip can wrap around the polished rod 2-3 times. For example, the length of the rubber strip is 300 mm.

[0017] To further reduce production costs and turn waste into treasure, preferably, the rubber strip is made from waste rubber belts and / or waste packing recycled from oilfield sites as rubber raw materials.

[0018] Furthermore, when adding the semi-solid lubricant, spread the semi-solid lubricant evenly on the rubber strip layer.

[0019] Furthermore, during the alternating insertion of rubber strips and grease, the inserted rubber strips and semi-solid lubricant are compressed.

[0020] The technical solution adopted by the oil pumping unit sealing packing of the present invention is as follows:

[0021] A pumping unit sealing packing includes a rubber strip and a semi-solid lubricant. This invention reduces wear and extends the service life of the packing, eliminates the difficulties of adding and removing packing, and is particularly suitable for wells where the polished rod is not centered. It simplifies the operation process and provides excellent sealing. This invention's pumping unit sealing packing can be used simply by adding two dovetail-type insert washers to the existing packing box, requiring no additional investment.

[0022] Furthermore, the semi-solid lubricant is composed of the following components in weight fractions: 2.5 to 5 parts of molybdenum disulfide lithium-based grease, 5 to 15 parts of graphite powder, 10 to 20 parts of lead powder, and 5 to 10 parts of bentonite.

[0023] Further, the graphite powder has an average particle size of 15–20 μm, and the lead powder has an average particle size of 26–30 μm; the bentonite is a base bentonite; and the rubber strip has a diameter of 5–7 mm. Further, the rubber strip can wrap around the smooth rod 2–3 times. For example, the length of the rubber strip is 300 mm. Further, the organobentonite has an average particle size of 30–50 μm.

[0024] Furthermore, the rubber strip is made from waste rubber belts and / or waste packing recycled from the oilfield site.

[0025] Furthermore, when using the oil pump sealing packing of the present invention, the mass ratio of the rubber strip to the semi-solid lubricant is controlled to be 40-65:22.5-60. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the dovetail-type insert washer used in Example 1;

[0027] Figure 2 This is a schematic diagram of the wellhead packing box under pressure after the wellhead seal of the pumping unit polished rod in Example 1;

[0028] Among them, 1-smooth rod, 2-gland, 3-packing cap, 4-dovetail plug washer, 5-rubber strip, 6-semi-solid lubricant, 7-semi-annular plug piece. Detailed Implementation

[0029] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0030] Example 1

[0031] The wellhead sealing method for the polished rod of the pumping unit in this embodiment includes the following steps:

[0032] 1) Stop the pumping unit, and then stop the donkey head in a position that is easy to operate;

[0033] 2) Close the rubber gate;

[0034] 3) Remove the packing gland and gland, and use the smooth rod clips to fix the packing gland and gland to the smooth rod;

[0035] 4) Remove the old packing;

[0036] 5) Install sealing packing: First, install a dovetail insert washer on the bare rod and place it at the bottom of the packing cavity. Then, alternately put rubber strips and semi-solid lubricant into the packing box until it is full. Finally, put another dovetail insert washer on the bare rod and install it above the packing.

[0037] During the alternating insertion of rubber strips and grease, each time a rubber strip is inserted, it is inserted into the packing box cavity clockwise around the smooth rod and a layer is laid out in the packing box cavity (the rubber strip is wrapped around the smooth rod multiple times); each time a semi-solid lubricant is inserted, a layer of semi-solid lubricant is evenly spread on the rubber strip layer.

[0038] During the alternating insertion of rubber strips and grease, the inserted rubber strips and semi-solid lubricant are compressed; after the packing box is filled, the mass ratio of rubber strips to semi-solid lubricant in the packing box cavity is 65:22.5.

[0039] The semi-solid lubricant used is a mixture of the following components in parts by weight: 3 parts lithium molybdenum disulfide grease, 12 parts graphite powder, 10 parts lead powder, and 10 parts organobentonite; the average particle size of the graphite powder is 20 μm, the average particle size of the lead powder is 30 μm, and the average particle size of the organobentonite is 30 μm; the rubber strip has a diameter of 5 mm and a length of 300 mm; the rubber strip is made from waste rubber belts and waste packing recycled from the oilfield as rubber raw materials; the semi-solid lubricant is obtained by mixing the lithium molybdenum disulfide grease, graphite powder, lead powder, and bentonite in a mixer at room temperature until homogeneous.

[0040] 6) Install the gland and packing gland cap, and tighten them. After tightening, the rubber strip and semi-solid lubricant are compacted and formed in the packing box cavity (stuffing chamber), forming an irregular packing body. Then, open the rubber gate, release the brake to start pumping, and closely observe for leaks. If there is a slight leak, tighten the packing box again until there is no leak.

[0041] In this embodiment, the diagram illustrates the pressure exerted on the wellhead packing box after the packing material has been loaded and the packing cap tightened. Figure 1 As shown, 1-smooth rod, 2-gland, 3-packing cap, 4-dovetail insert washer, 5-rubber strip, 6-semi-solid lubricant.

[0042] The annular dovetail insert washer used in this embodiment is as follows: Figure 2 As shown, it is formed by connecting two semi-annular plug pieces 7 end to end. The first end of each semi-annular plug piece 7 is a dovetail plug, and the last end is a dovetail slot that matches the dovetail plug at the first end. The annular space between the smooth rod and the packing box cavity matches the width of the annular dovetail plug washer.

[0043] Example 2

[0044] The difference between the oil pumping unit polished rod wellhead sealing method of this embodiment and the oil pumping unit polished rod wellhead sealing method of Embodiment 1 is only that: the semi-solid lubricant used in step 4) is composed of the following components in parts by weight: 3 parts of molybdenum disulfide lithium-based grease, 10 parts of graphite powder, 10 parts of lead powder, and 8 parts of organic bentonite; the average particle size of the graphite powder is 20 μm, the average particle size of the lead powder is 26 μm, and the average particle size of the organic bentonite is 40 μm; the diameter of the rubber strip is 5 mm and the length is 300 mm; after the packing box is filled, the mass ratio of the rubber strip and the semi-solid lubricant placed in the packing box cavity is 40:60.

[0045] Example 3

[0046] The difference between the oil wellhead sealing method of this embodiment and the oil wellhead sealing method of Embodiment 1 is only that: the semi-solid lubricant used in step 4) is composed of the following components in parts by weight: 5 parts of lithium molybdenum disulfide grease, 13 parts of graphite powder, 13 parts of lead powder, and 10 parts of organobentonite; the average particle size of the graphite powder is 20 μm, the average particle size of the lead powder is 28 μm, and the average particle size of the organobentonite is 50 μm; the diameter of the rubber strip is 5 mm and the length is 300 mm; after the packing box is filled, the mass ratio of the rubber strip and the semi-solid lubricant placed in the packing box cavity is 55:45.

[0047] Example 4

[0048] The difference between the oil well polished rod sealing method of this embodiment and the oil well polished rod sealing method of Embodiment 1 is only that: the semi-solid lubricant used in step 4) is composed of the following components in parts by weight: 4 parts of molybdenum disulfide lithium-based grease, 5 parts of graphite powder, 15 parts of lead powder, and 7 parts of organic bentonite; the average particle size of the graphite powder is 15 μm, and the average particle size of the lead powder is 30 μm.

[0049] Example 5

[0050] The difference between the oil well polished rod sealing method of this embodiment and the oil well polished rod sealing method of Embodiment 1 is only that: the semi-solid lubricant used in step 4) is composed of the following components in parts by weight: 2.5 parts of molybdenum disulfide lithium-based grease, 15 parts of graphite powder, 20 parts of lead powder, and 5 parts of organic bentonite; the average particle size of the graphite powder is 20 μm, and the average particle size of the lead powder is 30 μm.

[0051] Example 6

[0052] The difference between the oil well polished rod sealing method of this embodiment and the oil well polished rod sealing method of Embodiment 1 is only that: the semi-solid lubricant used in step 4) is composed of the following components in parts by weight: 5 parts of molybdenum disulfide lithium-based grease, 15 parts of graphite powder, 10 parts of lead powder, and 10 parts of organic bentonite; the average particle size of the graphite powder is 7 μm, and the average particle size of the lead powder is 26 μm.

[0053] The normal service life of an "O"-ring rubber seal is 3 to 4 months. When the polished rod is not centered, the service life is severely shortened to 1 to 2 months. The wellhead sealing method of the polished rod of the pumping unit described in Examples 1 to 6 can extend the service life of the packing to 6 to 8 months when the polished rod is not centered.

[0054] Example 7

[0055] The pumping unit sealing packing in this embodiment includes a rubber strip and a semi-solid lubricant. The rubber strip is made from waste rubber belts and waste packing recycled from the oilfield as rubber raw materials, with a diameter of 5 mm and a length of 300 mm. The semi-solid lubricant consists of the following components in parts by weight: 4 parts of lithium molybdenum disulfide grease, 5 parts of graphite powder, 15 parts of lead powder, and 7 parts of organic bentonite. The average particle size of the graphite powder is 15 μm, and the average particle size of the lead powder is 30 μm.

[0056] Example 8

[0057] The pumping unit sealing packing in this embodiment includes a rubber strip and a semi-solid lubricant. The rubber strip is made from waste rubber belts and waste packing recycled from the oilfield as rubber raw materials, with a diameter of 5 mm and a length of 300 mm. The semi-solid lubricant consists of the following components in parts by weight: 2.5 parts of lithium molybdenum disulfide grease, 15 parts of graphite powder, 20 parts of lead powder, and 5 parts of organic bentonite. The average particle size of the graphite powder is 20 μm, and the average particle size of the lead powder is 30 μm.

[0058] Example 9

[0059] The pumping unit sealing packing in this embodiment includes a rubber strip and a semi-solid lubricant. The rubber strip is made from waste rubber belts and waste packing recycled from the oilfield as rubber raw materials, with a diameter of 5 mm and a length of 300 mm. The semi-solid lubricant consists of the following components in parts by weight: 5 parts of lithium molybdenum disulfide grease, 15 parts of graphite powder, 10 parts of lead powder, and 10 parts of organic bentonite. The average particle size of the graphite powder is 7 μm, and the average particle size of the lead powder is 26 μm.

Claims

1. A method for sealing the wellhead of a pumping unit's polished rod, characterized in that: Includes the following steps: Place an annular washer on the polished rod and insert it into the bottom of the packing box cavity at the wellhead. Then, alternately place rubber strips and semi-solid lubricant into the packing box cavity until it is full. Next, place the annular washer on the polished rod, install the gland and packing cap, and tighten them. When placing the rubber strips, arrange them around the polished rod and spread them evenly in the packing box cavity. The mass ratio of the rubber strips to the semi-solid lubricant is 40~65:22.5~60. During the alternating placement process, the placed rubber strips and semi-solid lubricant are compressed layer by layer. The rubber strip is made from waste rubber belts and / or waste packing recycled from the oilfield site; the semi-solid lubricant is composed of the following components in parts by weight: 2.5-5 parts of molybdenum disulfide lithium-based grease, 5-15 parts of graphite powder, 10-20 parts of lead powder, and 5-10 parts of organic bentonite. Place the annular washer onto the smooth rod, then install the gland and packing cap in sequence, and tighten the cap to the preset torque; the average particle size of the graphite powder is 15~20μm, the average particle size of the lead powder is 26~30μm, the average particle size of the organic bentonite is 30~50μm, and the diameter of the rubber strip is 5~7mm.

2. The wellhead sealing method for the polished rod of an oil pumping unit according to claim 1, characterized in that: The annular washer is an annular dovetail insert washer.

3. The method for sealing the polished rod wellhead of a pumping unit according to claim 1, characterized in that: When adding semi-solid lubricant, spread it evenly on the rubber strip layer.

4. A sealing packing for an oil pumping unit, characterized in that: The product includes a rubber strip and a semi-solid lubricant; the semi-solid lubricant is composed of the following components in parts by weight: 2.5-5 parts of lithium molybdenum disulfide grease, 5-15 parts of graphite powder, 10-20 parts of lead powder, and 5-10 parts of organobentonite; the average particle size of the graphite powder is 15-20 μm, the average particle size of the lead powder is 26-30 μm, the average particle size of the organobentonite is 30-50 μm, and the diameter of the rubber strip is 5-7 mm.

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