A wear-resistant tower-type packing for oil drilling equipment and a preparation method thereof

Abstract

The application discloses a wear-resistant tower type packing for petroleum drilling equipment, which comprises a packing, the packing is a tower type spiral packing, and the packing is composed of a rubber matrix and reinforcing cloth; the rubber matrix is made from the following raw materials in parts by weight: 100 parts of rubber compound, 1-1.5 parts of stearic acid, 30-40 parts of filler, 20-25 parts of N330 carbon black, 8-10 parts of graphite, 2.3-2.6 parts of sulfur, 2.4-3 parts of accelerator, and 12-15 parts of dioctyl phthalate. The rubber matrix has high wear resistance and resilience, and the reinforcing cloth is distributed in the rubber matrix in the transverse direction, so that the service life of the packing is greatly prolonged.

Description

Technical Field

[0001] This invention relates to the field of oil drilling and production equipment technology, and in particular to a wear-resistant tower-type packing for oil drilling and production equipment and its preparation method. Background Technology

[0002] Packing for oil drilling and production equipment, such as the packing box for oil wells, is a sealing device at the wellhead. When the polished rod moves up and down, it seals against the packing inside the packing box. Because oil wells operate continuously, the packing wears down constantly. If the packing wears down or deforms, it can easily affect the sealing of the oil well and may cause problems such as oil spills. Therefore, packing for oil drilling and production equipment needs to have excellent wear resistance, oil resistance, and heat resistance.

[0003] In existing technologies, the most commonly used packing for oil drilling and production equipment is the spiral-stuffed packing, which is cone-shaped or tower-shaped and is embedded in the polished rod of the oil well to provide a seal. Because the polished rod operates continuously, the packing needs good wear resistance and resilience. To increase the wear resistance of the spiral packing, a rubberized fabric layer is wrapped around the inner side that contacts the polished rod. The disadvantages of this structure are: 1. Under longitudinal friction with the polished rod, the rubberized fabric is prone to rolling up from the rubber, affecting the packing's sealing performance; 2. The preparation process for the rubberized fabric layer is relatively complicated; 3. If the rubber's wear resistance is insufficient, the rubberized fabric layer has limited effect on improving wear resistance, thus leading to frequent packing replacements and a short service life. Summary of the Invention

[0004] In view of this, the purpose of this invention is to address the shortcomings of the prior art by providing a wear-resistant tower-type packing for oil drilling and production equipment. The rubber matrix used has high wear resistance and resilience, and reinforcing fabric is distributed laterally in the rubber matrix, thereby greatly enhancing the service life of the packing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A wear-resistant tower-type packing for oil drilling equipment includes a packing, wherein the packing is a tower-type spiral packing, and the packing is composed of a rubber matrix and reinforcing fabric. The rubber matrix is ​​made of the following raw materials in parts by weight: 100 parts of compound rubber, 1-1.5 parts of stearic acid, 30-40 parts of filler, 20-25 parts of N330 carbon black, 8-10 parts of graphite, 2.3-2.6 parts of sulfur, 2.4-3 parts of accelerator, and 12-15 parts of dioctyl phthalate.

[0007] Furthermore, the compound is a mixture of nitrile rubber and butadiene rubber in a weight ratio of 7-8:2.

[0008] Furthermore, the accelerator is a mixture of accelerator DM and accelerator CZ in a weight ratio of 1:1.

[0009] Furthermore, the filler is a mixture of zinc oxide whiskers, aluminum magnesium hydrotalcite and nano silicon nitride in a weight ratio of 5:5:1-2.

[0010] Furthermore, CeO2 is loaded onto the zinc oxide whiskers, and the loading method includes the following steps:

[0011] Ce(NO3)3·6H2O and PVP-K30 were dispersed in an aqueous ethanol solution, and zinc oxide whiskers were added. The mixture was stirred at 170-180℃ for 24-28 hours, centrifuged, washed and dried to obtain the product. The weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O and PVP-K30 was 9-10:2:1.

[0012] Furthermore, the aluminum-magnesium hydrotalcite is a modified aluminum-magnesium hydrotalcite, prepared by the following steps:

[0013] Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid. The molar ratio of 1,10-decanediamine to citric acid was 3:2. The mixture was stirred for 20-30 min, refluxed at 60-70 °C for 2 h, allowed to stand for 24 h, and the precipitate was filtered out, washed, and dried to obtain product I.

[0014] Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1-1.5:1 and dispersed in ethanol. The mixture was refluxed and stirred at 90°C for 18-20 hours. After filtration, washing, and drying, the product was obtained.

[0015] A method for preparing a wear-resistant tower-type packing includes the following steps:

[0016] 1) Add the compounded rubber to the internal mixer and plasticize it. After wrapping the rollers, add stearic acid, filler, N330 carbon black, graphite and dioctyl phthalate and mix. After mixing evenly, add sulfur and accelerator and continue mixing. After mixing evenly, discharge the material.

[0017] 2) Mix the product from step 1) with the solvent to form a paste, dip the paste onto the reinforcing fabric and then dry it to form an adhesive fabric;

[0018] 3) Cut the adhesive tape into rings, stack them on the cylinder in the mold, pre-press them into shape, then fill the mold with the adhesive material prepared in step 1), press and vulcanize them, and then cut them into spirals to obtain the product.

[0019] Furthermore, the reinforcing fabric is polytetrafluoroethylene fiber fabric or aramid fiber fabric.

[0020] The beneficial effects of this invention are:

[0021] 1. This application develops a wear-resistant tower-type packing for oil drilling and production equipment, wherein the packing is a spiral-reinforced packing with good wear resistance and resilience of the rubber matrix, and the reinforcement layers are horizontally stacked, exhibiting excellent wear resistance at the contact point with the polished rod; moreover, the processing technology is simple.

[0022] 2. The compound is made of nitrile rubber and butadiene rubber. Nitrile rubber has good oil resistance and stability. When mixed with butadiene rubber, it can improve the wear resistance and resilience of the rubber, which helps to extend the service life of the packing.

[0023] 3. To enhance the wear resistance and resilience of the rubber matrix, the composition of the rubber matrix raw materials was improved and optimized. The filler consisted of a mixture of zinc oxide whiskers, aluminum-magnesium hydrotalcite (ALH), and nano-silicon nitride in a specific weight ratio. APH HDH has a layered structure, and the zinc oxide whiskers have a specific aspect ratio, making them easier to disperse and less prone to agglomeration in the rubber matrix after mixing with nano-silicon nitride. Furthermore, after intercalation modification, the APH HDH has increased active sites, resulting in stronger interfacial bonding and repair capabilities with the rubber, thus improving its mechanical properties and resilience. Zinc oxide whiskers not only enhance the mechanical properties of the rubber, but the CeO2 they support also increases its wear resistance. Nano-silicon nitride primarily improves the wear resistance of the rubber by reducing the coefficient of friction at high temperatures. These three filler components synergistically enhance the mechanical properties and wear resistance of the rubber. The final prepared rubber matrix exhibits excellent wear resistance, resilience, and oil resistance, increasing the service life of the packing. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the packing structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the packing structure in the mold.

[0026] In the diagram: 1-packing, 2-reinforcing fabric, 3-rubber matrix, 4-mold, 5-cylinder, 6-through hole. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] A wear-resistant tower-type packing for oil drilling and production equipment, comprising packing 1, see [reference]. Figure 1-2 Packing 1 is a tower-shaped spiral packing, composed of a rubber matrix 3 and multiple layers of reinforcing fabric 2, with a central through-hole 6 to match the smooth rod structure. Figure 2 This is a schematic diagram of the packing material in mold 4. A cylinder 5 is set at the center of mold 4, which is the same as the smooth rod structure.

[0030] The rubber matrix is ​​made from the following raw materials in parts by weight: 100 parts compound rubber, 1 part stearic acid, 30 parts filler, 20 parts N330 carbon black, 8 parts graphite, 2.3 parts sulfur, 2.4 parts accelerator, and 12 parts dioctyl phthalate.

[0031] The accelerator is a mixture of accelerator DM and accelerator CZ in a weight ratio of 1:1; the compound is a mixture of nitrile rubber and butadiene rubber in a weight ratio of 7:2.

[0032] The filler is a mixture of zinc oxide whiskers, aluminum-magnesium hydrotalcite and nano-silicon nitride in a weight ratio of 5:5:1, wherein the zinc oxide whiskers have a diameter of 0.5-5μm and a length of 10-40μm.

[0033] The method for loading CeO2 onto zinc oxide whiskers includes the following steps:

[0034] Ce(NO3)3·6H2O and PVP-K30 were dispersed in 5 times their weight of an aqueous ethanol solution (ethanol to water volume ratio 1:1), stirred until homogeneous, and then zinc oxide whiskers were added. The mixture was stirred at 170℃ for 28 h, centrifuged, washed and dried to obtain the product, wherein the weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O and PVP-K30 was 9:2:1.

[0035] The modified aluminum-magnesium hydrotalcite is prepared by the following steps:

[0036] Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid, wherein the molar ratio of 1,10-decanediamine to citric acid was 3:2. The mixture was stirred for 20 min, then refluxed at 60 °C for 2 h, allowed to stand for 24 h, the precipitate was filtered out, washed and dried to obtain product I.

[0037] Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1:1 and dispersed in 4 times their weight of ethanol. The mixture was refluxed and stirred at 90°C for 18 hours, filtered, washed, and dried to obtain the final product.

[0038] A method for preparing packing includes the following steps:

[0039] 1) Add the compounded rubber to the internal mixer and plasticize it. After wrapping the rollers, add stearic acid, filler, N330 carbon black, graphite and dioctyl phthalate and mix. After mixing evenly, add sulfur and accelerator and continue mixing. After mixing evenly, discharge the material.

[0040] 2) Mix the product and solvent in step 1) at a weight ratio of 1:1.5 to prepare a paste (the solvent is toluene). Dip the paste into the reinforcing fabric and dry it to form a cloth. The reinforcing fabric is polytetrafluoroethylene fiber cloth with a thickness of 1 mm. After the paste is dipped and dried, the dry adhesive thickness on both sides is 0.5 mm.

[0041] 3) Cut the adhesive tape into rings, wherein the width of the adhesive tape rings is 0.5-1 times the width of the rings on the lower surface of the packing; in this embodiment, it is 0.5 times. Stack the cut rings of adhesive tape onto the packing as follows: Figure 2 The cylinder 5 in the mold 4 shown is first pre-pressed, and then the rubber material prepared in step 1) is filled into the mold, vulcanized (150℃, 15MPa, 20min), and then spiral cut to obtain the packing product.

[0042] Example 2

[0043] The difference between Example 2 and Example 1 is that:

[0044] The rubber matrix is ​​made from the following raw materials in parts by weight: 100 parts compound rubber, 1.2 parts stearic acid, 32 parts filler, 22 parts N330 carbon black, 9 parts graphite, 2.4 parts sulfur, 2.6 parts accelerator, and 13 parts dioctyl phthalate.

[0045] The compound is made by mixing nitrile rubber and butadiene rubber in a weight ratio of 7.5:2.

[0046] The filler is a mixture of zinc oxide whiskers, aluminum-magnesium hydrotalcite and nano-silicon nitride in a weight ratio of 5:5:1.5, wherein the zinc oxide whiskers have a diameter of 0.5-5μm and a length of 10-40μm.

[0047] The method for loading CeO2 onto zinc oxide whiskers includes the following steps:

[0048] Ce(NO3)3·6H2O and PVP-K30 were dispersed in an ethanol-water solution (volume ratio 1:1) and stirred until homogeneous. Then zinc oxide whiskers were added, and the mixture was stirred at 175°C for 24 hours. After centrifugation, washing, and drying, the product was obtained, wherein the weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O, and PVP-K30 was 9.5:2:1.

[0049] The modified aluminum-magnesium hydrotalcite is prepared by the following steps:

[0050] Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid, wherein the molar ratio of 1,10-decanediamine to citric acid was 3:2. The mixture was stirred for 30 min, then refluxed at 65 °C for 2 h, allowed to stand for 24 h, the precipitate was filtered out, washed and dried to obtain product I.

[0051] Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1.2:1 and dispersed in 3 times their weight of ethanol. The mixture was refluxed and stirred at 90°C for 20 hours, filtered, washed, and dried to obtain the final product.

[0052] Example 3

[0053] The difference between Example 3 and Example 1 is that:

[0054] The rubber matrix is ​​made from the following raw materials in parts by weight: 100 parts compound rubber, 1.4 parts stearic acid, 36 parts filler, 24 parts N330 carbon black, 9.5 parts graphite, 2.5 parts sulfur, 2.8 parts accelerator, and 14 parts dioctyl phthalate.

[0055] The compound is made by mixing nitrile rubber and butadiene rubber in a weight ratio of 7.5:2.

[0056] The filler is a mixture of zinc oxide whiskers, aluminum-magnesium hydrotalcite and nano-silicon nitride in a weight ratio of 5:5:1.5, wherein the zinc oxide whiskers have a diameter of 0.5-5μm and a length of 10-40μm.

[0057] The method for loading CeO2 onto zinc oxide whiskers includes the following steps:

[0058] Ce(NO3)3·6H2O and PVP-K30 were dispersed in an ethanol-water solution (volume ratio 1:1) and stirred until homogeneous. Then zinc oxide whiskers were added, and the mixture was stirred at 180°C for 24 hours. After centrifugation, washing, and drying, the product was obtained, wherein the weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O, and PVP-K30 was 9.5:2:1.

[0059] The modified aluminum-magnesium hydrotalcite is prepared by the following steps:

[0060] Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid, wherein the molar ratio of 1,10-decanediamine to citric acid was 3:2. The mixture was stirred for 25 min, then refluxed at 70 °C for 2 h, allowed to stand for 24 h, the precipitate was filtered out, washed and dried to obtain product I.

[0061] Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1.5:1 and dispersed in 4 times their weight of ethanol. The mixture was refluxed and stirred at 90°C for 19 hours, filtered, washed, and dried to obtain the product.

[0062] Example 4

[0063] The difference between Example 4 and Example 1 is that:

[0064] The rubber matrix is ​​made from the following raw materials in parts by weight: 100 parts compound rubber, 1.5 parts stearic acid, 40 parts filler, 25 parts N330 carbon black, 10 parts graphite, 2.6 parts sulfur, 3.0 parts accelerator, and 15 parts dioctyl phthalate.

[0065] The compound is made by mixing nitrile rubber and butadiene rubber in a weight ratio of 8:2.

[0066] The filler is a mixture of zinc oxide whiskers, aluminum-magnesium hydrotalcite and nano-silicon nitride in a weight ratio of 5:5:2, wherein the zinc oxide whiskers have a diameter of 0.5-5μm and a length of 10-40μm.

[0067] The method for loading CeO2 onto zinc oxide whiskers includes the following steps:

[0068] Ce(NO3)3·6H2O and PVP-K30 were dispersed in an ethanol-water solution (volume ratio 1:1) and stirred until homogeneous. Then zinc oxide whiskers were added, and the mixture was stirred at 175°C for 28 hours. After centrifugation, washing, and drying, the product was obtained, wherein the weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O, and PVP-K30 was 10:2:1.

[0069] The modified aluminum-magnesium hydrotalcite is prepared by the following steps:

[0070] Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid, wherein the molar ratio of 1,10-decanediamine to citric acid was 3:2. The mixture was stirred for 30 min, then refluxed at 70 °C for 2 h, allowed to stand for 24 h, the precipitate was filtered out, washed and dried to obtain product I.

[0071] Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1.5:1 and dispersed in 4 times their weight of ethanol. The mixture was refluxed and stirred at 90°C for 20 hours, filtered, washed, and dried to obtain the final product.

[0072] Comparative Example 1

[0073] Comparative Example 1 is a comparative example of Example 4, except that the filler is entirely zinc oxide whiskers, and CeO2 is loaded on the zinc oxide whiskers.

[0074] Comparative Example 2

[0075] Comparative Example 2 is a comparative example of Example 4, the difference being:

[0076] The filler is nano-silicon nitride.

[0077] Comparative Example 3

[0078] Comparative Example 3 is a comparative example of Example 4, except that the filler is aluminum-magnesium hydrotalcite, and the aluminum-magnesium hydrotalcite is modified aluminum-magnesium hydrotalcite.

[0079] Comparative Example 4

[0080] Comparative Example 4 is a comparative example to Comparative Example 3, except that the filler is aluminum-magnesium hydrotalcite, and the aluminum-magnesium hydrotalcite is not modified.

[0081] Comparative Example 5

[0082] Comparative Example 5 is a comparative example of Example 4, except that the filler is a 1:1 mixture of zinc oxide whiskers and aluminum-magnesium hydrotalcite, wherein the zinc oxide whiskers are loaded with CeO2 and the magnesium-aluminum hydrotalcite is a modified magnesium-aluminum hydrotalcite.

[0083] Comparative Example 6

[0084] Comparative Example 6 is a comparative example of Example 4, except that the filler is a mixture of zinc oxide whiskers and nano-silicon nitride in a weight ratio of 10:2, and CeO2 is loaded on the zinc oxide whiskers.

[0085] Performance testing

[0086] The abrasion resistance (GB / T 1689-2014 "Determination of Abrasion Resistance of Vulcanized Rubber"), compression set (23℃, 24h), tensile strength, and oil resistance (1# test oil (100℃×70h)) of the rubber matrices prepared in Examples 1-4 and Comparative Examples 1-6 were tested. At the same time, the rubber sheets prepared in Examples 1-4 were stacked, pre-pressed, and then vulcanized to form test blocks. The abrasion resistance of the cloth-packed test blocks was tested. The results are shown in Table 1.

[0087] Table 1 Performance Test Results

[0088]

[0089] As can be seen from the results in Table 1, the rubber matrix prepared in this application has high tensile strength, oil and wear resistance, and good resilience, and can be used as a high-quality packing material. The cloth-added packing test block prepared after cloth addition has excellent wear resistance. When used in oil drilling and production equipment, it can greatly improve the service life of the packing.

[0090] The data from the comparative examples show that the filler in Comparative Examples 1-3, being a single component, exhibited significantly higher wear resistance than Example 4. Comparative Examples 5-6, with two filler components, showed a marked improvement in wear resistance compared to Comparative Examples 1-3, but still fell far short of Example 4. This indicates that the three filler components in this application have a significant synergistic effect in enhancing wear resistance. Furthermore, compared to Comparative Example 3, Comparative Example 4, whose aluminum-magnesium hydrotalcite was not modified, showed a significant decrease in wear resistance, tensile strength, and compression set. This suggests that modification significantly impacts its bonding strength with the rubber matrix, thereby affecting the mechanical properties of the rubber matrix.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing wear-resistant tower-type packing for oil drilling and production equipment, characterized in that, The wear-resistant tower-type packing includes packing (1), which is a tower-type spiral packing. The packing (1) is composed of a rubber matrix (3) and reinforcing fabric (2). The rubber matrix is ​​made of the following raw materials in parts by weight: 100 parts of compound rubber, 1-1.5 parts of stearic acid, 30-40 parts of filler, 20-25 parts of N330 carbon black, 8-10 parts of graphite, 2.3-2.6 parts of sulfur, 2.4-3 parts of accelerator, and 12-15 parts of dioctyl phthalate. The filler is made of zinc oxide whiskers, aluminum magnesium hydrotalcite and nano silicon nitride mixed in a weight ratio of 5:5:1-2. The method for preparing the wear-resistant tower-type packing includes the following steps: 1) Add the compounded rubber to the internal mixer and plasticize it. After wrapping the rollers, add stearic acid, filler, N330 carbon black, graphite and dioctyl phthalate and mix. After mixing evenly, add sulfur and accelerator and continue mixing. After mixing evenly, discharge the material. 2) Mix the product from step 1) with the solvent to form a paste, dip the paste onto the reinforcing fabric and then dry it to form an adhesive fabric; 3) Cut the tape into rings, stack them on the cylinder (5) in the mold (4), pre-press them into shape, then fill the mold with the rubber material prepared in step 1), press and vulcanize them, and then cut them into spirals to obtain the product.

2. The method for preparing a wear-resistant tower-type packing for oil drilling and production equipment according to claim 1, characterized in that, The compound is a mixture of nitrile rubber and butadiene rubber in a weight ratio of 7-8:

2.

3. The method for preparing a wear-resistant tower-type packing for oil drilling and production equipment according to claim 1, characterized in that, The accelerator is a mixture of accelerator DM and accelerator CZ in a weight ratio of 1:

1.

4. The method for preparing a wear-resistant tower-type packing for oil drilling and production equipment according to claim 1, characterized in that, The zinc oxide whiskers are loaded with CeO2, and the loading method includes the following steps: Ce(NO3)3·6H2O and PVP-K30 were dispersed in an aqueous ethanol solution, and zinc oxide whiskers were added. The mixture was stirred at 170-180℃ for 24-28 hours, centrifuged, washed and dried to obtain the product. The weight ratio of zinc oxide whiskers, Ce(NO3)3·6H2O and PVP-K30 was 9-10:2:

1.

5. The method for preparing a wear-resistant tower-type packing for oil drilling and production equipment according to claim 1, characterized in that, The aluminum-magnesium hydrotalcite is a modified aluminum-magnesium hydrotalcite, prepared by the following steps: Under ice-water bath conditions, an ethanol solution of 1,10-decanediamine was slowly added dropwise to an ethanol solution of citric acid. The molar ratio of 1,10-decanediamine to citric acid was 3:

2. The mixture was stirred for 20-30 min, refluxed at 60-70 °C for 2 h, allowed to stand for 24 h, and the precipitate was filtered out, washed, and dried to obtain product I. Product I and aluminum-magnesium hydrotalcite were mixed at a weight ratio of 1-1.5:1 and dispersed in ethanol. The mixture was refluxed and stirred at 90°C for 18-20 hours. After filtration, washing, and drying, the product was obtained.

6. The method for preparing a wear-resistant tower-type packing for oil drilling and production equipment according to claim 1, characterized in that, The reinforcing fabric is polytetrafluoroethylene fiber fabric or aramid fiber fabric.

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