High-strength and high-activity resin-based solid low-density lightweight material and preparation method thereof

Abstract

The invention discloses a preparation method of a high-strength and high-activity resin-based solid low-density lightweight material, which specifically comprises the following steps: preheating resin, slowly adding a coupling agent, and stirring; adding an inorganic reinforcing filler, stirring, cooling, adding a curing agent, stirring, pouring into a mold, carrying out ultrasonic treatment, and carrying out segmented heating curing, crushing, cleaning and drying to obtain a high-strength resin-based core material; the preparation method comprises the following steps: dispersing a nano hydrated reinforcing material in ethanol, adding a sol-gel method precursor and a catalyst to form sol, immersing a cross-linked high-strength resin-based core material into the nano reinforcing material sol, and carrying out ultrasonic treatment and calcination to obtain the high-strength and high-activity resin-based solid low-density lightweight material for well cementation. The high-strength and high-activity resin-based solid low-density lightweight material disclosed by the invention has the advantages of higher compressive strength, high temperature resistance, adjustable density and the like, and is suitable for well cementation operation of weak formations and low-pressure formations in oil and gas fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of petroleum engineering material preparation, and specifically relates to a high-strength and highly active resin-based solid low-density weighting material, and also relates to a preparation method of the high-strength and highly active resin-based solid low-density weighting material. Background Art

[0002] With the continuous deepening of oil and gas field exploration and development, various complex and changeable formations have been encountered, among which there are weak formations and low-pressure formations, so the problem of cementing loss has become increasingly prominent. There are mainly the following two measures to solve the low-pressure loss well: (1) adopting a loss prevention cementing process, such as a staged cementing process; (2) using a low-density cement slurry system for cementing, and the low-density weighting material is the key to the performance of the low-density cement slurry system.

[0003] In view of this, introducing low-density lightening materials into the Portland cement slurry system is an important breakthrough to solve the problems in cementing operations for weak bottom formations and low-pressure lost circulation formations. However, traditional lightening materials, such as bentonite, slag, fly ash, etc., are only directly added into the cement slurry system as admixtures, and their action mechanisms are merely to improve the performance of the cement slurry system through the water absorption properties of the materials themselves and simple hydration reactions. Therefore, there are problems such as weak adjustment ability, poor effect, and inability to meet the dual requirements of density and strength. In this regard, Chinese Patent (Application No.: 201710040782.5, Publication No.: CN106753295A, Publication Date: January 20, 2017) discloses an active lightening material for low-density cement slurry and its preparation method. After preheating bisphenol F-type epoxy resin, a coupling agent and active fillers are added and stirred, and then a curing agent is added for single-temperature curing at 90°C, and then crushed to obtain the active lightening material. Due to the presence of the resin matrix, this lightening material has strong compressive ability, and the coupling agent serves as a "bridge" to graft the organic resin and inorganic fillers, improving the interfacial properties between the polymer material and the inorganic fillers, enabling them to be strongly combined. The addition of inorganic fillers has somewhat improved the hydrophilic properties of the lightening material. However, this existing lightening material still has the following technical problems: 1) Although the compressive strength of the lightening material itself is improved due to the presence of the resin matrix, the rapid curing of the curing agent at high temperature will cause the problem of internal stress concentration, and there may be incomplete curing of the resin matrix inside the material and weak crosslinking degree, affecting the mechanical properties of the lightening material; 2) In the initial stage of the curing reaction, the preferential wetting effect of the organic resin matrix on the fillers may trigger an adsorption competition mechanism, resulting in the formation of a continuous phase coating layer of the resin phase on the surface of the fillers. To a certain extent, the micron-scale coating layer limits the dispersion degree of the lightening material in the cement slurry system; 3) During the curing process, the surface coating effect of the organic resin on the active fillers may trigger a significant interfacial passivation phenomenon. The coating layer will shield the active functional groups (such as hydroxyl groups, silanol groups, etc.) on the surface of the active fillers, resulting in a significant reduction in their specific surface energy and significant inhibition of their hydration activity, making it difficult to effectively participate in the hydration reaction system of Portland cement and unable to form sufficient chemical bonding and mechanical interlocking with cement hydration products (such as C-S-H gel, ettringite, etc.).

[0004] Therefore, there is an urgent need to develop a high-strength - high-activity resin-based solid low-density lightening material with high compressive strength, good hydrophilic properties, and strong hydration activity, which can better participate in the hydration reaction process of Portland cement and effectively improve the interfacial bonding force between itself and Portland cement. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength - high-activity resin-based solid low-density lightening material to solve the problems of low thermal stability and poor compressive strength of existing lightening materials.

[0006] Another object of the present invention is to provide a method for preparing a high-strength and high-activity resin-based solid low-density lightening material.

[0007] The technical solution adopted by the present invention is that the high-strength and high-activity resin-based solid low-density lightening material includes a high-strength resin-based core material and a high-activity gel coating, and the high-activity gel coating is coated on the high-strength resin-based core material.

[0008] The characteristics of the present invention also lie in that The high-strength resin-based core material includes the following components in weight percentages: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%, and the sum of the above component weights is 100%; the curing agent is T31 phenolic amine or triethanolamine; the coupling agent is any one or more of silane coupling agent KH-550, titanate coupling agent TC-201, and aluminate coupling agent DL-411; the inorganic reinforcing filler is any one or more of slag, diatomite, and fly ash; The high-activity gel coating includes the following components in weight percentages: interfacial bridging agent 1.92% - 10.26%, nano-hydration reinforcing material 11.76% - 25%, sol-gel method precursor 42.55% - 63.63%, catalyst 14.06% - 32.50%, and the sum of the above component weights is 100%. The interfacial bridging agent is any one or more of silane coupling agent KH-550, silane coupling agent KH-560, and silane coupling agent KH-570; the nano-hydration reinforcing material is any one or more of nano-SiO2, nano-Al2O3, and nano-AlOOH; the sol-gel method precursor is tetraethyl orthosilicate; the catalyst is any one or more of ammonia water, dilute hydrochloric acid, and glacial acetic acid.

[0009] Another technical solution adopted by the present invention is a method for preparing a high-strength and high-activity resin-based solid low-density lightening material, specifically: preheating the resin, slowly adding the coupling agent and stirring; then adding the inorganic reinforcing filler and stirring, cooling and then adding the curing agent and stirring, pouring into a mold and performing ultrasonic treatment, and then performing segmented heating and curing, pulverizing, cleaning and drying to obtain the high-strength resin-based core material; dispersing the nano-hydration reinforcing material in ethanol, adding the sol-gel method precursor and the catalyst to form a sol, immersing the crosslinked high-strength resin-based core material in the nano-reinforcing material sol, performing ultrasonic treatment, and calcining to obtain the high-strength and high-activity resin-based solid low-density lightening material for well cementing; specifically implemented according to the following steps: S1. Weigh the following components according to weight percentages: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%, and the sum of the above component weights is 100%; S2. Place the resin in a reaction kettle, preheat it to 80°C - 90°C to make its viscosity reach 100 - 150 mPa·s, then slowly add the coupling agent and stir for 20 - 30 min; S3. Add the dry inorganic reinforcing filler into the reaction kettle, continue to stir for 30 - 40 min, cool down the reaction system, add the curing agent, stir for 5 - 10 min, pour it into a mold coated with a release agent, then place the mold in an ultrasonic instrument for treatment, and then carry out segmented heating and curing. After demolding, crush it, sieve it, ultrasonically clean it with absolute ethanol, and dry it to obtain the high-strength resin-based core material; S4. Weigh the following components according to weight percentage: interfacial bridging agent 1.92% - 10.26%, nano-hydrated reinforcing material 11.76% - 25%, sol-gel precursor 42.55% - 63.63%, catalyst 14.06% - 32.50%, and the sum of the weights of the above components is 100%; S5. Immerse the high-strength resin-based core material in the interfacial bridging agent solvent, stir, and dry to obtain the cross-linked high-strength resin-based core material; S6. Disperse the nano-hydrated reinforcing material in an ethanol solvent, then add the sol-gel precursor and the catalyst to form a nano-reinforcing material sol. Then immerse the cross-linked high-strength resin-based core material in the nano-reinforcing material sol, carry out ultrasonic treatment, and finally carry out calcination to obtain the high-strength - high-activity resin-based solid low-density weighting material for well cementing.

[0010] In step S3, the process of segmented heating and curing is as follows: Transfer the mold to an oven and cure it at 70 - 85°C for 1 - 3 h to form a flexible cross-linked network, and then cure it at 90 - 100°C for 2 - 3 h to enhance the cross-linking density, and then the curing can be completed.

[0011] In step S5, the preparation process of the interfacial bridging agent solvent is as follows: Place the interfacial bridging agent in the solvent and stir for 10 - 20 min to obtain the interfacial bridging agent solvent; the solvent is composed of ethanol and water mixed.

[0012] In step S6, the calcination temperature is 150 - 250°C and the calcination time is 3 - 5 h.

[0013] The beneficial effects of the present invention are: (1) For the preparation process of the high-strength resin-based core material of the present invention, an adapted segmented curing process is adopted to avoid the problem of uneven curing distribution caused by the internal stress concentration caused by the rapid curing of the curing agent at high temperature, and significantly improve the compressive capacity of the high-strength resin-based core material.

[0014] (2) For the high-strength resin-based core material of the present invention, the inorganic reinforcing material is selected from one or more of slag, diatomite, and fly ash, realizing the resource utilization of industrial solid waste and reducing costs. Among them, there is a strong interfacial interaction between the inorganic reinforcing filler and the epoxy resin, inhibiting the thermal movement of the epoxy chain segments, and increasing the temperature resistance of the high-strength resin-based core material. (3) For the high-activity gel coating process of the present invention, a dense nano-hydrated material coating layer is formed on the high-strength resin-based core material. Nano-SiO2, nano-Al2O3, and nano-AlOOH in the nano-reinforcing material can better participate in the cement hydration reaction process, enhancing the compatibility between the material itself and portland cement.

[0015] (4) The high-strength and high-activity resin-based solid low-density lightening material of the present invention has the advantages of high compressive strength, high temperature resistance, and adjustable density, etc., and is suitable for cementing operations in weak formations and low-pressure formations existing in oil and gas fields; moreover, the preparation process is simple, easy to operate, has a low construction cost, and is suitable for large-scale industrial production. Description of the Drawings

[0016] Figure 1 It is a relationship diagram of the addition amount of the high-strength and high-activity resin-based solid low-density lightening materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 and the compressive strength of the cured cement stone. Detailed Embodiments

[0017] The present invention will be described in detail below in conjunction with the detailed embodiments and the drawings.

[0018] The high-strength and high-activity resin-based solid low-density lightening material of the present invention includes a high-strength resin-based core material and a high-activity gel coating, and the high-activity gel coating is coated on the high-strength resin-based core material; The high-strength resin-based core material includes the following components in weight percentages: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%, and the sum of the above component weight percentages is 100%; The curing agent is T31 phenolic amine or triethanolamine; The coupling agent is any one or more of silane coupling agent KH-550, titanate coupling agent TC-201, and aluminate coupling agent DL-411; The inorganic reinforcing filler is any one or more of slag, diatomite, and fly ash; The high-strength resin-based core material uses resin as the matrix and is heated and cured by adding a curing agent to form a three-dimensional network structure. The three-dimensional cross-linked network can significantly improve the tensile strength, flexural strength, and compressive properties of the material through the close connection of molecular chains. In addition, there is a strong interfacial interaction between the inorganic reinforcing filler and the resin matrix in the high-strength resin-based core material, which inhibits the thermal movement of epoxy segments. The presence of a coupling agent effectively improves the internal phase interface of the resin, forming chemical bonds between the inorganic reinforcing filler and the resin, and also restricting the movement of polymer segments. Due to this dual synergistic effect, the glass transition temperature of the high-strength resin-based core material is significantly increased.

[0019] The high-activity gel coating comprises components in the following weight percentages: 1.92% - 10.26% of an interfacial bridging agent, 11.76% - 25% of a nano-hydration reinforcing material, 42.55% - 63.63% of a sol-gel precursor, and 14.06% - 32.50% of a catalyst, and the sum of the weight percentages of the above components is 100%; The interfacial bridging agent is any one or more of silane coupling agent KH-550, silane coupling agent KH-560, and silane coupling agent KH-570; The nano-hydration reinforcing material is any one or more of nano-SiO2, nano-Al2O3, and nano-AlOOH; The sol-gel precursor is tetraethyl orthosilicate; The catalyst is any one or more of ammonia water, dilute hydrochloric acid, and glacial acetic acid; The sol-gel precursor is tetraethyl orthosilicate, which can hydrolyze to form a SiO2 three-dimensional network, and the hydrolysis and polycondensation reaction can be precisely regulated by the catalyst, and then a uniform and dense nano-porous structure can be formed. The silane coupling agent can hydrolyze to form silanol groups, which undergo a condensation reaction with the hydroxyl groups (-OH) on the substrate surface to form stable Si-O-Si covalent bonds and provide a large number of attachment sites for the nano-hydration reinforcing material. The nano-particles can be dispersed in the sol-gel network through the "pinning effect" to inhibit crack propagation. Among them, nano-SiO2 can improve the coating hardness, and the layered structure of nano-AlOOH can improve the fracture toughness. In addition, the nano-hydration reinforcing material significantly enhances the reduction of the hydration activity of the material, can better participate in the hydration process of portland cement, and the nano-hydration reinforcing material can effectively fill the nano-porous structure to improve the denseness of the gel coating.

[0020] The preparation method of the high-strength and high-activity resin-based solid low-density lightweight material of the present invention is specifically implemented according to the following steps: S1. Weigh the following components by weight percentage: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%. The sum of the weights of the above components is 100%. S2. Place the resin in a reaction kettle and preheat it to 80°C - 90°C. Monitor the fluidity through an on-line viscometer to make its viscosity reach 100 - 150 mPa·s (similar to the fluidity of water). Then slowly add the coupling agent to the above resin matrix with good fluidity and stir for 20 - 30 min at a stirring speed of 200 r / min. Observe with a microscope to ensure there are no agglomerated particles. S3. Add the dried inorganic reinforcing filler to the reaction kettle and continue to stir for 30 - 40 min at a stirring speed of 300 r / min to ensure uniform dispersion of the inorganic filler. Lower the temperature of the reaction system to 45°C, add the curing agent, stir for 5 - 10 min at a stirring speed of 200 r / min, pour it into a mold coated with a release agent, and then place the mold in a 40 kHz ultrasonic instrument for 20 min to eliminate micron-sized bubbles (porosity < 1%). Then carry out segmented heating and curing. After demolding, crush it, pass through a 60-mesh sieve, ultrasonically clean it with absolute ethanol for 10 min to remove surface impurities, and dry it at 80°C to obtain a high-strength resin-based core material. The process of segmented heating and curing is as follows: First, transfer the mold to an oven and cure it at 70 - 85°C for 1 - 3 h to form a flexible cross-linked network, and then cure it at 90 - 100°C for 2 - 3 h to enhance the cross-linking density, thus completing the curing. S4. Weigh the following components by weight percentage: interfacial bridging agent 1.92% - 10.26%, nano-hydration reinforcing material 11.76% - 25%, sol-gel method precursor 42.55% - 63.63%, catalyst 14.06% - 32.50%. The sum of the weights of the above components is 100%. S5. Immerse the high-strength resin-based core material in the interfacial bridging agent solvent and stir at 60°C for 2 h to ensure that after the hydrolysis of the silane, a -Si-O-C covalent bond is formed with the hydroxyl groups on the resin surface. Then place it in an oven and dry it at 120°C for 1.5 h to complete the cross-linking of the interfacial bridging agent and obtain the cross-linked high-strength resin-based core material. The preparation process of the interfacial bridging agent solvent is as follows: Place the interfacial bridging agent in the solvent and stir for 10 - 20 min to obtain the interfacial bridging agent solvent. The solvent is composed of ethanol and water mixed in a mass ratio of 8:2. S6. Disperse the nano-hydration strengthening material (with a particle size of 20 nm) in an ethanol solvent (solid content: 3% - 5%), then add the sol-gel precursor and catalyst to form a nano-strengthening material sol. Next, immerse the crosslinked high-strength resin-based core material into the nano-strengthening material sol, place it in a 40 kHz ultrasonic instrument for 30 min to evenly adsorb the sol on the surface, and finally conduct calcination at a temperature of 150 - 250 °C for 3 - 5 h to form a dense nano-hydration material coating layer. After cooling and discharging, the high-strength and highly active resin-based solid low-density weighting material for well cementing can be obtained. The high-strength resin-based core material of the present invention includes a resin matrix, an inorganic reinforcing filler, a coupling agent, and a curing agent. By adopting an adapted segmented curing process, the resin-based core material has good compressive and temperature resistance properties. The highly active gel coating includes an interfacial bridging agent, a nano-hydration strengthening material, a sol-gel precursor, and a catalyst. It adheres to the surface of the resin-based core material through the gel coating process to form a dense nano-hydration active layer, enabling the polymer to have good hydrophilic ability and hydration activity, thereby enhancing the interfacial reaction activity with the cement slurry, rather than simply being dispersed in the cement as a filler.

[0021] Example 1 The high-strength and highly active resin-based solid low-density weighting material includes a high-strength resin-based core material and a highly active gel coating. The high-strength resin-based core material includes components with the following weight percentages: epoxy resin E-51 70.42 wt%, silane coupling agent KH-550 1.41 wt%, inorganic reinforcing filler (mass ratio of slag: diatomaceous earth: fly ash is 5:3:2) 17.61 wt%, phenolic amine T31 curing agent 10.56 wt%; the highly active gel coating includes components with the following weight percentages: silane coupling agent KH-550 4.55 wt%, nano-AlOOH 15.90 wt%, tetraethyl orthosilicate 54.55 wt%, ammonia water 25.00 wt%.

[0022] The preparation method of the above high-strength and highly active resin-based solid low-density weighting material includes the following steps: S1. Place the resin in a reaction kettle equipped with a thermometer and mechanical stirring, preheat to 80 °C, monitor the fluidity through an on-line viscometer, and when it reaches 100 mPa·s, slowly add the coupling agent to the above resin matrix with good fluidity and continuously stir at a mechanical speed of 200 r / min for 20 min. Observe under a microscope to ensure there are no agglomerated particles.

[0023] S2. Add the dried inorganic reinforcing filler (mass ratio of slag: diatomite: fly ash is 5:3:2) into the reaction kettle, continue to stir for 30 min at a rotation speed of 300 r / min to ensure the uniform dispersion of the inorganic filler. Lower the temperature of the reaction system to 45 °C, add the curing agent, set the mechanical rotation speed at 200 r / min, stir for 5 min, and then pour it into the mold coated with the release agent.

[0024] S3. Place the mold in a 40 kHz ultrasonic instrument for 20 min to eliminate microbubbles (porosity < 1%). Then, perform segmented heat curing. Transfer the mold to the oven and cure it at 80 °C for 2 h to form a flexible cross-linked network, and then cure it at 90 °C for 2.5 h to enhance the cross-linking density. After demolding, crush and screen it to obtain a high-strength resin-based core material with a particle size of 60 mesh.

[0025] S4. Ultrasonically clean the high-strength resin-based core material with absolute ethanol for 10 minutes to remove surface impurities, and dry it at 80 °C for standby. Place the silane coupling agent KH-550 in the solvent (mass ratio of ethanol to water is 8:2), stir for 10 min, and set aside.

[0026] S5. Immerse the high-strength resin-based core material in the above solvent, stir at a constant temperature of 60 °C for 2 h to ensure that after the hydrolysis of the silane, a -Si-O-C covalent bond is formed with the hydroxyl groups on the resin surface. Then, place it in the oven and dry it with hot air at 120 °C for 1.5 h to complete the cross-linking of the interfacial bridging agent.

[0027] S6. Disperse nano-AlOOH (particle size 20 nm) in ethanol with a solid content of 3%, then add tetraethyl orthosilicate and ammonia water to form a nano-reinforced material sol. Then, immerse the high-strength resin-based core material in the nano-reinforced material sol, place it in a 40 kHz ultrasonic instrument for 30 min to make the sol uniformly adsorb on the surface, and then place it in the oven and calcine it at 200 °C for 4 h to form a dense nano-hydrated material coating layer. After cooling, discharge the material to obtain a high-strength and highly active resin-based solid low-density weighting material for well cementing.

[0028] Example 2 The high-strength and highly active resin-based solid low-density weighting material includes a high-strength resin-based core material and a highly active gel coating. The high-strength resin-based core material includes the following components by weight percentage: epoxy resin E-51 65.79 wt%, silane coupling agent KH-550 1.33 wt%, inorganic reinforcing filler (mass ratio of slag: diatomite: fly ash is 5:3:2) 20.44 wt%, phenolic amine T31 curing agent 12.44 wt%; the highly active gel coating includes the following components by weight percentage: silane coupling agent KH-550 6.98 wt%, nano-AlOOH 18.60 wt%, tetraethyl orthosilicate 51.16 wt%, ammonia water 23.26 wt%. The preparation method of the above high-strength and high-activity resin-based solid low-density lightweight material comprises the following steps: S1. Place the resin in a reaction kettle equipped with a thermometer and a mechanical stirring device, preheat it to 85°C, monitor the fluidity through an on-line viscometer, when it reaches 120 mPa·s, slowly add the coupling agent to the above resin matrix with good fluidity, and continuously stir, with a mechanical rotation speed of 200 r / min, stir for 25 min, and observe under a microscope to ensure that there are no agglomerated particles.

[0029] S2. Add the pre-dried inorganic reinforcing filler (the mass ratio of slag: diatomite: fly ash is 5:3:2) to the reaction kettle, continue to stir for 35 min, with a mechanical rotation speed of 300 r / min, ensure that the inorganic filler is evenly dispersed, lower the temperature of the reaction system to 45°C, add the curing agent, with a mechanical rotation speed of 200 r / min, stir for 8 min, and pour it into a mold coated with a release agent.

[0030] S3. Place the mold in a 40 kHz ultrasonic instrument and process it for 20 min to eliminate micron-sized bubbles (porosity < 1%). Then, perform segmented heating and curing. Transfer the mold to an oven and cure it at 80°C for 2 h to form a flexible cross-linked network, and then cure it at 90°C for 2.5 h to enhance the cross-linking density. After demolding, crush and screen it to obtain a high-strength resin-based core material with a particle size of 60 mesh.

[0031] S4. Ultrasonically clean the high-strength resin-based core material with absolute ethanol for 10 minutes to remove surface impurities, dry it at 80°C for standby. Place the silane coupling agent KH-550 in an ethanol / water solvent, stir for 15 min, and set aside.

[0032] S5. Immerse the high-strength resin-based core material in the above solvent, stir at a constant temperature of 60°C for 2 h to ensure that after the silane hydrolysis, a -Si-O-C covalent bond is formed with the hydroxyl groups on the resin surface, and then place it in an oven for hot air drying at 120°C for 1.5 h to complete the cross-linking of the interfacial bridging agent.

[0033] S6. Disperse nano-AlOOH in ethanol, then add tetraethyl orthosilicate and ammonia water to form a nano-reinforced material sol. Then, immerse the high-strength resin-based core material in the nano-reinforced material sol, place it in a 40 kHz ultrasonic instrument and process it for 30 min to make the sol evenly adsorbed on the surface, and then place it in an oven for calcination at 200°C for 4 h to form a dense nano-hydrated material coating layer. After cooling, discharge it to obtain the high-strength and high-activity resin-based solid low-density lightweight material for well cementing.

[0034] Example 3 High-strength and highly active resin-based solid low-density lightweight material, comprising a high-strength resin-based core material and a highly active gel coating; the high-strength resin-based core material comprises components in the following weight percentages: epoxy resin E-51 65.79 wt%, silane coupling agent KH-550 1.31 wt%, inorganic reinforcing filler (slag: diatomite: fly ash in a mass ratio of 5:3:2) 23.03 wt%, phenolic amine T31 curing agent 9.87 wt%. The highly active gel coating comprises components in the following weight percentages: silane coupling agent KH-550 4.35 wt%, nano-AlOOH 17.39 wt%, tetraethyl orthosilicate 52.17 wt%, ammonia water 26.09 wt%.

[0035] The preparation method of the above high-strength and highly active resin-based solid low-density lightweight material comprises the following steps: S1. Place the resin in a reaction kettle equipped with a thermometer and a mechanical stirring device, preheat to 90 °C, monitor the fluidity through an on-line viscometer, when it reaches 150 mPa·s (similar to the fluidity of water), then slowly add the coupling agent to the above resin matrix with good fluidity, and continuously stir, with a mechanical rotation speed of 200 r / min, stir for 30 min, and observe under a microscope to ensure no agglomerated particles.

[0036] S2. Add 23.03 wt% of pre-dried inorganic reinforcing filler to the reaction kettle, continue to stir for 40 min, with a mechanical rotation speed of 300 r / min, ensure the uniform dispersion of the inorganic filler, lower the temperature of the reaction system to 45 °C, add the curing agent, with a mechanical rotation speed of 200 r / min, stir for 10 min, and pour it into a mold coated with a release agent.

[0037] S3. Place the mold in a 40 kHz ultrasonic instrument and process for 20 min to eliminate micro-scale bubbles (porosity < 1%). Then carry out segmented heating and curing. Transfer the mold to an oven and cure at 80 °C for 2 h to form a flexible cross-linked network, and then cure at 90 °C for 2.5 h to enhance the cross-linking density. After demolding, crush and sieve to obtain a high-strength resin-based core material with a particle size of 60 mesh.

[0038] S4. Ultrasonically clean the high-strength resin-based core material with absolute ethanol for 10 minutes to remove surface impurities, dry at 80 °C for standby. Place 4.35 wt% of silane coupling agent KH-550 in a solvent, stir for 20 min, and set aside.

[0039] S5. Immerse the high-strength resin-based core material in the above solvent, stir at a constant temperature of 60 °C for 2 h to ensure that after the silane hydrolysis, a -Si-O-C- covalent bond is formed with the hydroxyl groups on the resin surface, and then place it in an oven for hot air drying at 120 °C for 1.5 h to complete the cross-linking of the interfacial bridging agent.

[0040] S6. Disperse nano-AlOOH in ethanol with a solid content of 3%, then add tetraethyl orthosilicate and ammonia water to form a nano-enhanced material sol. Then immerse the high-strength resin-based core material into the nano-enhanced material sol, place it in a 40 kHz ultrasonic instrument for 30 minutes to make the sol evenly adsorbed on the surface, and then place it in an oven for calcination at 200 °C for 4 hours to form a dense nano-hydrated material coating layer. After cooling and discharging, the high-strength and highly active resin-based solid low-density lightening material for well cementing can be obtained.

[0041] Comparative Example 1 (single-temperature curing) The high-strength and highly active resin-based solid low-density lightening material includes a high-strength resin-based core material and a highly active gel coating; it includes the following components in weight percentages: Specifically, it consists of the following components in weight percentages. The weight percentage composition of the high-strength resin-based core material includes: epoxy resin E-51 70.42 wt%, silane coupling agent KH-550 1.41 wt%, inorganic reinforcing filler (the mass ratio of slag: diatomite: fly ash is 5:3:2) 17.61 wt%, phenolic amine T31 curing agent 10.56 wt%. The highly active gel coating includes the following components in weight percentages: silane coupling agent KH-550 4.55 wt%, nano-AlOOH 15.90 wt%, tetraethyl orthosilicate 54.55 wt%, ammonia water 25.00 wt%.

[0042] The preparation method of the above high-strength and highly active resin-based solid low-density lightening material includes the following steps: S1. Place the resin in a reaction kettle equipped with a thermometer and mechanical stirring, preheat it to 80 °C, monitor the fluidity through an on-line viscometer, and when it reaches 100 mPa·s, slowly add the coupling agent to the above resin matrix with good fluidity and keep stirring. The mechanical rotation speed is 200 r / min, and stir for 20 minutes. Observe with a microscope to ensure that there are no agglomerated particles.

[0043] S2. Add the dried inorganic reinforcing filler (the mass ratio of slag: diatomite: fly ash is 5:3:2) to the reaction kettle, continue to stir for 30 minutes, the mechanical rotation speed is 300 r / min, ensure that the inorganic filler is evenly dispersed, lower the temperature of the reaction system to 45 °C, add the curing agent, the mechanical rotation speed is 200 r / min, stir for 5 minutes, and pour it into a mold coated with a release agent.

[0044] S3. Place the mold in a 40 kHz ultrasonic instrument for 20 minutes to eliminate micro-scale bubbles (porosity < 1%). Then transfer the mold to an oven and cure it at 90 °C for 4.5 hours. After demolding, crush and screen it to obtain a high-strength resin-based core material with a particle size of 60 mesh.

[0045] S4. Ultrasonically clean the high-strength resin-based core material with absolute ethanol for 10 minutes to remove surface impurities, then dry it at 80 °C for later use. Place the silane coupling agent KH-550 in a solvent (the mass ratio of ethanol to water is 8:2), stir for 10 min, and set aside.

[0046] S5. Immerse the high-strength resin-based core material in the above solvent, stir at a constant temperature of 60 °C for 2 hours to ensure that after the silane hydrolyzes, a -Si-O-C- covalent bond is formed with the hydroxyl groups on the resin surface, and then place it in an oven for hot air drying at 120 °C for 1.5 hours to complete the cross-linking of the interfacial bridging agent.

[0047] S6. Disperse nano-AlOOH (particle size 20 nm) in ethanol with a solid content of 3%, then add tetraethyl orthosilicate and ammonia water to form a nano-enhanced material sol. Then immerse the high-strength resin-based core material in the nano-enhanced material sol, place it in a 40 kHz ultrasonic instrument for treatment for 30 min to make the sol evenly adsorbed on the surface, and then place it in an oven for calcination at 200 °C for 4 hours to form a dense nano-hydrated material coating layer. After cooling and discharging, a high-strength and highly active resin-based solid low-density weighting material for well cementing can be obtained.

[0048] Comparative Example 2 (Single-temperature curing + No coating modification with highly active gel) The high-strength and highly active resin-based solid low-density weighting material includes a high-strength resin-based core material. The high-strength resin-based core material includes the following components in weight percentage: epoxy resin E-51 70.42 wt%, silane coupling agent KH-550 1.41 wt%, inorganic reinforcing filler (the mass ratio of slag: diatomite: fly ash is 5:3:2) 17.61 wt%, phenolic amine T31 curing agent 10.56 wt%.

[0049] The preparation method of the above high-strength and highly active resin-based solid low-density weighting material includes the following steps: S1. Place the resin in a reaction kettle equipped with a thermometer and a mechanical stirring device, preheat to 80 °C, monitor the fluidity through an on-line viscometer, and when it reaches 100 mPa·s, slowly add the coupling agent to the above resin matrix with good fluidity and continuously stir, with a mechanical rotation speed of 200 r / min and stir for 20 min. Observe with a microscope to ensure that there are no agglomerated particles.

[0050] S2. Add the dried inorganic reinforcing filler (the mass ratio of slag: diatomite: fly ash is 5:3:2) to the reaction device, continue to stir for 30 min, with a mechanical rotation speed of 300 r / min to ensure uniform dispersion of the inorganic filler. Lower the temperature of the reaction system to 45 °C, add 10.56 wt% curing agent, with a mechanical rotation speed of 200 r / min, stir for 5 min, and pour it into a mold coated with a release agent.

[0051] S3. The mold was placed in a 40 kHz ultrasonic instrument and processed for 20 min to eliminate micron-sized bubbles (porosity < 1%). Then, the mold was transferred to an oven and cured at 90 °C for 4.5 h. After demolding, it was crushed and sieved to obtain a high-strength resin-based core material with a particle size of 60 mesh.

[0052] Example 4 Performance test The high-strength and highly active resin-based solid low-density lightweight materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for compressive strength, density, and glass transition temperature. The specific methods are as follows: Compressive strength: A universal material testing machine was used. A cylindrical sample ( Φ 25 mm × 50 mm) was compressed at a rate of 2 mm / min until rupture, and the maximum load was recorded.

[0053] Glass transition temperature test: The prepared high-strength and highly active resin-based solid low-density lightweight material (60 mm in length, 13 mm in width, and 2.5 mm in thickness) was placed in a dynamic thermomechanical analyzer. With a heating rate of 5 °C / min, the glass transition temperature of the material could be obtained by analyzing the data.

[0054] Contact angle test: The sample was placed in a contact angle tester, and the data could be accurately measured.

[0055] Density test: The crushed high-strength and highly active resin-based solid low-density lightweight material was transferred to a pycnometer, and the density of the material could be obtained using the formula.

[0056] During measurement, the powder sample was pre-dried and then loaded into the pycnometer. Its volume accounted for about 1 / 2 or 1 / 3 of the volume inside the bottle. After weighing the mass of the pycnometer and the powder sample, the bottle was filled with liquid, the stopper was tightly plugged, the overflowing liquid was wiped dry, and then the mass was weighed again. Then, the density was calculated according to the following formula:

[0057] In the formula, m1 is the mass of the pycnometer; m2 is the total mass of the pycnometer and the powder; m3 is the total mass of the pycnometer plus the powder plus the filled liquid; ρ 水 is the density of water at room temperature, taking 1 g / cm 3 ; V is the fixed volume of the pycnometer; ρ is the density of the sample; Example 5 The high-strength and highly active resin-based solid low-density lightweight materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for compressive strength, as shown in Table 1; Table 1 Test results of compressive strength of high-strength and highly active resin-based solid low-density lightweight materials

[0058] The glass transition temperatures of the high-strength and highly active resin-based solid low-density lightweight materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, as shown in Table 2; Table 2 Test Results of Glass Transition Temperatures of High-Strength and Highly Active Resin-Based Solid Low-Density Lightweight Materials

[0059] The contact angles of the high-strength and highly active resin-based solid low-density lightweight materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, as shown in Table 3; Table 3 Test Results of Contact Angles of High-Strength and Highly Active Resin-Based Solid Low-Density Lightweight Materials

[0060] The densities of the high-strength and highly active resin-based solid low-density lightweight materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, as shown in Table 4; Table 4 Test Results of Densities of High-Strength and Highly Active Resin-Based Solid Low-Density Lightweight Materials

[0061] The above results show that the high-strength and highly active resin-based solid low-density lightweight material of the present invention has a low density, good high-temperature resistance, and excellent compressive strength. (1) The high-strength and highly active resin-based solid low-density lightweight material of the present invention has excellent compressive properties, all greater than 70 MPa at room temperature. Compared with Comparative Example 1 (single-temperature curing), the compressive properties of the high-strength and highly active resin-based solid low-density lightweight material in Example 1 (stepwise heating process) are improved by about 33.14%. (2) The high-strength and highly active resin-based solid low-density lightweight material of the present invention has good high-temperature resistance, and the glass transition temperatures of Examples 1 to 3 are all greater than 100 °C; (3) The high-strength and highly active resin-based solid low-density lightweight material of the present invention has excellent hydrophilic properties, and the contact angles of Examples 1 to 3 are all less than 25°. Compared with Comparative Example 1 and Comparative Example 2, the secondary modification with a highly active gel coating makes the hydrophilic properties of the high-strength and highly active resin-based solid low-density lightweight material of the present invention significantly improved. Therefore, the material can be better dispersed in Portland cement and can better participate in the cement hydration process. (4) The high-strength and highly active resin-based solid low-density lightweight material of the present invention has a low density, and Examples 1 to 3 are all less than 1.2 g / cm 3 , and the material density shows a decreasing trend with the increase in the addition amount of the inorganic reinforcing filler; Example 6 Figure 1The high-strength and highly reactive resin-based solid low-density lightweight material of the present invention, by controlling its dosage in the cement slurry system, the change curve of the compressive strength of the cement stone cured at 80°C for 48 hours shows that the modification behavior of the highly reactive gel coating makes the composite material have good hydration activity, which is beneficial to the improvement of the bonding strength between the material and cement particles, and the material itself can better participate in the hydration activity of portland cement.

[0062] The high-strength and highly reactive resin-based solid low-density lightweight material of the present invention adopts an adapted segmented curing process. The internal curing degree of the high-strength resin-based core material is higher, the cross-linking degree is denser, and the compressive strength is significantly improved. The high-efficiency functional modification of the high-strength resin-based core material is realized through the gel coating process, and the hydrophilic property and hydration activity of the lightweight material are significantly improved, and the interfacial bonding force with portland cement is effectively guaranteed.

Claims

1. High-strength and high-activity resin-based solid low-density lightweight material, characterized in that, It includes a high-strength resin-based core material and a highly active gel coating, and the highly active gel coating is coated on the high-strength resin-based core material.

2. The high-strength and high-activity resin-based solid low-density lightweight material according to claim 1, characterized in that The high-strength resin-based core material includes the following components by weight percentage: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%, and the sum of the weights of the above components is 100%.

3. The high-strength and high-activity resin-based solid low-density lightweight material according to claim 2, characterized in that, The curing agent is T31 phenolic amine or triethanolamine; the coupling agent is any one or more of silane coupling agent KH-550, titanate coupling agent TC-201, and aluminate coupling agent DL-411; the inorganic reinforcing filler is any one or more of slag, diatomite, and fly ash.

4. The high-strength and high-activity resin-based solid low-density lightening material according to claim 1, characterized in that, The highly active gel coating includes the following components by weight percentage: interfacial bridging agent 1.92% - 10.26%, nano-hydration reinforcing material 11.76% - 25%, sol-gel precursor 42.55% - 63.63%, catalyst 14.06% - 32.50%, and the sum of the weights of the above components is 100%.

5. The high-strength and high-activity resin-based solid low-density lightweight material according to claim 4, characterized in that, The interfacial bridging agent is any one or more of silane coupling agent KH-550, silane coupling agent KH-560, and silane coupling agent KH-570; the nano-hydration reinforcing material is any one or more of nano-SiO2, nano-Al2O3, and nano-AlOOH; the sol-gel precursor is tetraethyl orthosilicate; the catalyst is any one or more of ammonia water, dilute hydrochloric acid, and glacial acetic acid.

6. Preparation method of high-strength and high-activity resin-based solid low-density lightening material, characterized in that, Specifically: preheat the resin, slowly add the coupling agent and stir; then add the inorganic reinforcing filler and stir, cool down and add the curing agent, stir, pour into a mold and perform ultrasonic treatment, then carry out segmented heating and curing, crush, wash and dry to obtain the high-strength resin-based core material; disperse the nano-hydration reinforcing material in ethanol, add the sol-gel precursor and the catalyst to form a sol, immerse the cross-linked high-strength resin-based core material in the nano-reinforcing material sol, perform ultrasonic treatment, and calcine to obtain the high-strength and highly active resin-based solid low-density weight-reducing material for well cementing.

7. The preparation method of the high-strength and high-activity resin-based solid low-density lightening material according to claim 6, characterized in that Specifically, it is implemented according to the following steps: S1. Weigh the following components according to the weight percentage: resin 59.52% - 79.37%, coupling agent 0.60% - 2.34%, inorganic reinforcing filler 10.14% - 21.08%, curing agent 6.76% - 20.55%, and the sum of the weights of the above components is 100%; S2. Place the resin in a reaction kettle, preheat it to 80°C - 90°C to make its viscosity reach 100 - 150 mPa·s, then slowly add the coupling agent and stir for 20 - 30 min; S3. Add the dry inorganic reinforcing filler to the reaction kettle, continue to stir for 30 - 40 min, cool down the reaction system, add the curing agent, stir for 5 - 10 min, pour into a mold coated with a release agent, then place the mold in an ultrasonic instrument for treatment, then carry out segmented heating and curing, demold, crush, sieve, ultrasonically clean with anhydrous ethanol, and dry to obtain the high-strength resin-based core material; S4. Weigh the following components by weight percentage: 1.92% - 10.26% of the interfacial bridging agent, 11.76% - 25% of the nano-hydration strengthening material, 42.55% - 63.63% of the sol-gel precursor, and 14.06% - 32.50% of the catalyst. The sum of the weights of the above components is 100%. S5. Immerse the high-strength resin-based core material in the interfacial bridging agent solvent, stir, and dry to obtain the crosslinked high-strength resin-based core material. S6. Disperse the nano-hydration strengthening material in an ethanol solvent, then add the sol-gel precursor and the catalyst to form a nano-strengthening material sol. Then immerse the crosslinked high-strength resin-based core material in the nano-strengthening material sol, perform ultrasonic treatment, and finally conduct calcination to obtain the high-strength and highly active resin-based solid low-density weight-reducing material for well cementing.

8. The preparation method of the high-strength and high-activity resin-based solid low-density lightening material according to claim 7, characterized in that, In the step S3, the process of segmented heating and curing is as follows: Transfer the mold to an oven and cure it at 70 - 85 °C for 1 - 3 h to form a flexible crosslinked network, and then cure it at 90 - 100 °C for 2 - 3 h to enhance the crosslinking density, thus completing the curing.

9. The preparation method of the high-strength and high-activity resin-based solid low-density lightening material according to claim 7, characterized in that, In the step S5, the preparation process of the interfacial bridging agent solvent is as follows: Place the interfacial bridging agent in the solvent and stir for 10 - 20 min to obtain the interfacial bridging agent solvent; the solvent is composed of a mixture of ethanol and water.

10. The preparation method of the high-strength and high-activity resin-based solid low-density lightening material according to claim 7, characterized in that, In the step S6, the calcination temperature is 150 - 250 °C, and the calcination time is 3 - 5 h.

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