A high-density functional ball for a multiple-switch plug-and-abandonment circulation tool and a method of making the same

Abstract

The application provides a high-density functional ball for a multiple switch plugging circulation tool and a preparation method thereof, and relates to the technical field of drilling tools. The high-density functional ball for the multiple switch plugging circulation tool is prepared from raw materials including polyether ether ketone 70-85%, copper powder 10-20% and silicon nitride 5-10% in terms of weight percentage. The preparation method comprises the following steps: mixing and drying the polyether ether ketone, the copper powder and the silicon nitride to obtain a mixture; melting the mixture at high temperature, then injecting the mixture into a spherical mold for pressure forming, and air cooling to room temperature to obtain a formed spherical body; and performing grading tempering treatment on the formed spherical body, and performing surface finishing treatment on the formed spherical body after cooling. The functional ball has the advantages of high density, stable shear pressure and good mechanical properties. The preparation process can improve the problems of the polyether ether ketone raw material, such as a large thermal expansion coefficient and stress concentration.

Description

Technical Field

[0001] This application relates to the field of drilling tool technology, and more specifically, to a high-density functional ball for a multiple-cycle plugging and sealing tool and its preparation method. Background Technology

[0002] The Multiple-Switch Positive Loss Circulation Tool (MCCS) is a tool used to manage wellbore fluid losses during drilling, particularly suitable for deepwater operations and complex lost-circulation situations. Located within the BHA (Bottomhole Tool Assembly), the MCCS delivers a high concentration of lost-circulation material (such as LCM) to the wellbore through multiple switching cycles when fluid loss occurs, thereby solidifying and maintaining wellbore control. The MCCS uses multiple switching cycles to allow the lost-circulation material to flow out through the bypass port of the circulation sub, preventing clogging and corrosion of the bottom hole assembly. This design makes the plugging process more efficient while reducing well control risks.

[0003] The development and application of MCCS (Multiple-Switch Circulation Tool) began in 2019. With the increase in deepwater operations and complex well leakage problems, MCCS has gradually become an effective tool for dealing with these issues. Its simple structure makes it suitable for widespread use, especially excelling in well sections requiring frequent leakage control. The multiple-switch plugging and circulation tool can perform multiple high-concentration, large-particle plugging operations, as well as well washing or casing cleaning, effectively reducing on-site well control risks, in the event of a leakage accident or other incident. However, the seals used in the multiple-switch plugging and circulation tool are susceptible to corrosion and damage under oil drilling conditions. The tool requires high sealing performance, especially since the two sets of sliding seals on the outer sleeve can directly lead to tool failure if damaged.

[0004] The main function of the activation ball is to control the opening of the bypass valve through ball-drop activation. When the ball enters a specific position of the bypass valve, it triggers the bypass valve's opening mechanism, thereby changing the downhole circulation conditions and achieving specific operational requirements. With the development of the drilling industry, the technical requirements for the activation balls used in multiple-stage plugging and circulation tools, such as sealing, high-temperature resistance, corrosion resistance, and shear pressure resistance, are gradually increasing. Currently, most activation balls are made of plastic or iron, which have the following disadvantages: the shear pressure of the activation balls used in current multiple-stage plugging and circulation tools is unstable, and the low density results in a slow sinking speed. Summary of the Invention

[0005] The purpose of this application is to provide a high-density functional ball for a multiple-cycle plugging and sealing tool, which has the advantages of high density, stable shear pressure and good mechanical properties.

[0006] Another objective of this application is to provide a method for preparing a high-density functional ball for a multiple-cycle plugging and sealing tool. This method can improve the problems of high thermal expansion coefficient and stress concentration inherent in polyether ether ketone raw materials.

[0007] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0008] On the one hand, this application provides a high-density functional ball for a multiple-cycle plugging and sealing tool. By weight percentage, the raw materials of the functional ball include 70-85% polyetheretherketone, 10-20% copper powder, and 5-10% silicon nitride.

[0009] On the other hand, this application provides a method for preparing a high-density functional ball for a multiple-cycle plugging and sealing tool, comprising the following steps:

[0010] S1. Polyetheretherketone, copper powder and silicon nitride are thoroughly mixed and dried to obtain a mixture;

[0011] S2. The mixture is melted at high temperature and then injected into a spherical mold for pressure molding. After being cooled to room temperature, the shaped sphere is obtained.

[0012] S3. The shaped sphere is subjected to graded tempering treatment, and then cooled and the surface of the sphere is finely machined to obtain the functional sphere.

[0013] Compared with the prior art, the embodiments of this application have at least the following advantages or beneficial effects:

[0014] Regarding the first aspect, this application uses polyetheretherketone (PEEK) as the main raw material for the functional balls. PEEK has a melting point of 334℃ and a low coefficient of friction, thus possessing advantages such as high temperature resistance and high mechanical strength. It can be used in harsh environments such as high temperature, high load, and strong corrosion, improving the stability of the functional balls. Copper powder and silicon nitride are compounded onto the PEEK base to improve the density and tensile strength of the functional balls. Copper powder, in particular, significantly increases the density of the functional balls, achieving a density of 2.1 g / cm³. 3 In this way, the functional spheres can achieve stable speed and shear pressure during sinking; silicon nitride improves the compatibility of the polyether ether ketone surface while increasing the density and tensile strength of the functional spheres, enhances the permeability and adhesion between copper powder and polymer, and improves the mixing effect.

[0015] Regarding the second aspect, the melting temperature of the preparation process in this application is set at 350-400℃, which allows polyetheretherketone to melt fully and mix evenly with silicon nitride and copper powder. Applying appropriate pressure during the molding process ensures good bonding between polyetheretherketone and copper powder. Considering the large coefficient of thermal expansion of polyetheretherketone, air cooling and staged tempering are used during cooling to improve its crystallinity and solve its stress concentration problem. In particular, the residual stress in the polyetheretherketone composite material can be released after tempering, so that a good interfacial bond can be formed between the filler and the polymer, improving the cracks or deformations that may occur in polyetheretherketone during processing and improving the mechanical properties of the functional spheres. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to specific embodiments.

[0018] A high-density functional ball for a multiple-cycle plugging and sealing tool, wherein the raw materials of the functional ball, by weight percentage, include 70-85% polyetheretherketone, 10-20% copper powder, and 5-10% silicon nitride.

[0019] In some embodiments of this application, the particle size of the copper powder is 1-10 μm, and the particle size of the silicon nitride is 5-20 μm.

[0020] A method for preparing a high-density functional ball for a multiple-cycle plugging and sealing tool includes the following steps:

[0021] S1. Polyetheretherketone, copper powder and silicon nitride are thoroughly mixed and dried to obtain a mixture;

[0022] S2. The mixture is melted at high temperature and then injected into a spherical mold for pressure molding. After being cooled to room temperature, the shaped sphere is obtained.

[0023] S3. The shaped sphere is subjected to graded tempering treatment, and then cooled and the surface of the sphere is finely machined to obtain the functional sphere.

[0024] In some embodiments of this application, the thorough mixing in step S1 above specifically involves stirring at a speed of 1000-2000 rpm for 10-50 minutes.

[0025] In some embodiments of this application, the drying in step S1 is specifically drying at a temperature of 90-110°C for 0.5-5 hours.

[0026] In some embodiments of this application, the high-temperature melting temperature in step S2 above is 350-400°C.

[0027] In some embodiments of this application, the pressure for pressure forming in step S2 above is 5-20 MPa.

[0028] In some embodiments of this application, the graded tempering treatment in step S3 above specifically involves tempering at 140-160°C for 1-3 hours, followed by tempering at 180-195°C for 1-2 hours.

[0029] In some embodiments of this application, the pressure during the above-mentioned tempering and heat preservation is 5-20 MPa.

[0030] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0031] Example 1

[0032] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0033] Raw materials to be prepared: 85% polyetheretherketone, 10% copper powder with a particle size of 1-5μm and 5% silicon nitride with a particle size of 5-20μm;

[0034] The above raw materials were placed in a high-speed mixer and mixed at 1800 rpm for 35 minutes, and then dried in a 105℃ dryer for 1.5 hours to obtain the mixture.

[0035] The mixture is melted at a high temperature of 380℃, then injected into a special spherical mold, and molded by applying a pressure of 20MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0036] The sphere is reintroduced into the muffle furnace and tempered at 145°C and 20MPa for 1 hour, then the temperature is adjusted to 185°C and tempered for 2 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0037] Example 2

[0038] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0039] Raw materials to be prepared: 75% polyetheretherketone, 20% copper powder with a particle size of 1-5μm and 5% silicon nitride with a particle size of 5-10μm;

[0040] The above raw materials were placed in a high-speed mixer and mixed at 1500 rpm for 35 minutes, and then dried in a 110°C dryer for 1 hour to obtain the mixture.

[0041] The mixture is melted at a high temperature of 390℃, then injected into a special spherical mold, and molded by applying a pressure of 10MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0042] The sphere is reintroduced into the muffle furnace and tempered at 155°C and 10MPa for 2 hours. Then, the temperature is adjusted to 185°C and tempered for 1.5 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0043] Example 3

[0044] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0045] Raw materials to be prepared: 75% polyetheretherketone, 15% copper powder with a particle size of 1-5μm and 10% silicon nitride with a particle size of 10-20μm;

[0046] The above raw materials were placed in a high-speed mixer and mixed at 2000 rpm for 35 minutes, and then dried in a 95°C dryer for 4 hours to obtain the mixture.

[0047] The mixture is melted at a high temperature of 380℃, then injected into a special spherical mold, and molded by applying a pressure of 15MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0048] The sphere is reintroduced into the muffle furnace and tempered at 150°C and 15MPa for 1 hour, then the temperature is adjusted to 185°C and tempered for 1.5 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0049] Example 4

[0050] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0051] Raw materials to be prepared: 80% polyetheretherketone, 10% copper powder with a particle size of 1-10μm and 10% silicon nitride with a particle size of 5-20μm;

[0052] The above raw materials were placed in a high-speed mixer and mixed at 1200 rpm for 50 minutes, and then dried in a 95°C dryer for 4.5 hours to obtain the mixture.

[0053] The mixture is melted at a high temperature of 380℃, then injected into a special spherical mold, and molded by applying a pressure of 15MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0054] The sphere is reintroduced into the muffle furnace and tempered at 155°C and 15MPa for 1 hour, then tempered at 190°C for 1.5 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0055] Example 5

[0056] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0057] Raw materials to be prepared: 75% polyetheretherketone, 15% copper powder with a particle size of 1-10μm and 10% silicon nitride with a particle size of 5-20μm;

[0058] The above raw materials were placed in a high-speed mixer and mixed at 1400 rpm for 30 minutes, and then dried in a 90°C dryer for 4.5 hours to obtain the mixture.

[0059] The mixture is melted at a high temperature of 380℃, then injected into a special spherical mold, and molded by applying a pressure of 10MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0060] The sphere is reintroduced into the muffle furnace and tempered at 155°C and 5MPa for 1 hour. Then, the temperature is adjusted to 190°C and tempered for 1.5 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0061] Example 6

[0062] A high-density functional ball for a multiple-cycle plugging and sealing tool is prepared by the following method:

[0063] Raw material preparation: 70% polyetheretherketone, 20% copper powder with a particle size of 1-10μm, and 10% silicon nitride with a particle size of 5-20μm;

[0064] The above raw materials were placed in a high-speed mixer and mixed at 1400 rpm for 30 minutes, and then dried in a 110℃ dryer for 1.5 hours to obtain the mixture.

[0065] The mixture is melted at a high temperature of 380℃, then injected into a special spherical mold, and molded by applying a pressure of 5MPa. After being cooled to room temperature by air, the shaped spheres are demolded.

[0066] The sphere is reintroduced into the muffle furnace and tempered at 160°C and 5MPa for 2.5 hours. Then, the temperature is adjusted to 190°C and tempered for 2 hours. Finally, after cooling, the surface of the sphere is finished to obtain the functional sphere of this embodiment.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is that silicon nitride is not added in this comparative example, and the raw materials are: 85% polyether ether ketone and 15% copper powder with a particle size of 1-5 μm.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 1 is that no copper powder is added in this comparative example. The raw materials are: 85% polyetheretherketone and 15% silicon nitride with a particle size of 5-20μm.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that the preparation process of this comparative example does not include a graded tempering step.

[0073] Comparative Example 4

[0074] The difference between this comparative example and Example 1 is that the tempering process in this comparative example uses isothermal tempering, which is carried out at 145°C and 20MPa for 3 hours.

[0075] The density and tensile strength of the functional spheres prepared in the examples and comparative examples were tested, and functional spheres prepared from 100% polyetheretherketone were used as a blank control group. The results are shown in Table 1.

[0076] Table 1

[0077] Example 1 2.15 169.2 Example 2 2.92 168.7 Comparative Example 1 2.44 158.5 Comparative Example 2 1.57 153.4 Comparative Example 3 2.15 148.9 Comparative Example 4 2.15 151.9 Blank control group 1.3 108.8

[0078] As can be seen from Table 1, compared with pure polyether ether ketone (100% polyether ether ketone), the functional spheres prepared in the examples and comparative examples have significantly improved density and tensile strength, which can significantly improve the mechanical properties of polymer functional spheres.

[0079] In summary, the high-density functional ball and its preparation method for a multiple-cycle plugging and sealing tool according to embodiments of this application have the following advantages:

[0080] Regarding the first aspect, this application uses polyetheretherketone (PEEK) as the main raw material for the functional balls. PEEK has a melting point of 334℃ and a low coefficient of friction, thus possessing advantages such as high temperature resistance and high mechanical strength. It can be used in harsh environments such as high temperature, high load, and strong corrosion, improving the stability of the functional balls. Copper powder and silicon nitride are compounded onto the PEEK base to improve the density and tensile strength of the functional balls. Copper powder, in particular, significantly increases the density of the functional balls, achieving a density of 2.1 g / cm³. 3 In this way, the functional spheres can achieve stable speed and shear pressure during sinking; silicon nitride improves the compatibility of the polyether ether ketone surface while increasing the density and tensile strength of the functional spheres, enhances the permeability and adhesion between copper powder and polymer, and improves the mixing effect.

[0081] Regarding the second aspect, the melting temperature of the preparation process in this application is set at 350-400℃, which allows polyetheretherketone to melt fully and mix evenly with silicon nitride and copper powder. Applying appropriate pressure during the molding process ensures good bonding between polyetheretherketone and copper powder. Considering the large coefficient of thermal expansion of polyetheretherketone, air cooling and staged tempering are used during cooling to improve its crystallinity and solve its stress concentration problem. In particular, the residual stress in the polyetheretherketone composite material can be released after tempering, so that a good interfacial bond can be formed between the filler and the polymer, improving the cracks or deformations that may occur in polyetheretherketone during processing and improving the mechanical properties of the functional spheres.

[0082] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A high-density functional ball for a multiple-cycle plugging and sealing tool, characterized in that, By weight percentage, the raw materials of the functional spheres include 70-85% polyetheretherketone, 10-20% copper powder, and 5-10% silicon nitride; The method for preparing the high-density functional ball for the multiple-cycle plugging and sealing tool includes the following steps: S1. Polyetheretherketone, copper powder and silicon nitride are thoroughly mixed and dried to obtain a mixture; S2. The mixture is melted at high temperature and then injected into a spherical mold for pressure molding. After being cooled to room temperature, the shaped sphere is obtained. S3. The molded sphere is subjected to graded tempering treatment, and then cooled and the surface of the sphere is finely machined to obtain the functional sphere. In step S2, the high-temperature melting temperature is 350-400℃; in step S3, the staged tempering treatment specifically involves tempering and holding at 140-160℃ for 1-3 hours, and then tempering and holding at 180-195℃ for 1-2 hours, with a pressure of 5-20MPa during tempering and holding.

2. The high-density functional ball for a multiple-cycle plugging and sealing tool according to claim 1, characterized in that, The copper powder has a particle size of 1-10 μm, and the silicon nitride has a particle size of 5-20 μm.

3. The high-density functional ball for a multiple-cycle plugging and sealing tool according to claim 1, characterized in that, The thorough mixing in step S1 specifically involves stirring at a speed of 1000-2000 rpm for 10-50 minutes.

4. A high-density functional ball for a multiple-cycle plugging and sealing tool according to claim 1, characterized in that, The drying process in step S1 involves drying at a temperature of 90-110℃ for 0.5-5 hours.

5. A high-density functional ball for a multiple-cycle plugging and sealing tool according to claim 1, characterized in that, The pressure for pressure forming in step S2 is 5-20 MPa.