Preparation method of high-temperature-resistant anti-degradation spherical adjuvant for oil and gas resource exploitation

Abstract

The application discloses a preparation method of a high-temperature-resistant anti-degradation spherical additive for oil and gas resource exploitation, and the content of each component in the raw material is calculated according to the total mass of the components as 100%, and the content of each component is as follows: 40-55% of silicon dioxide, 35-50% of di-aluminum trioxide, 1.2-5% of di-boron trioxide, 1.8-5% of alkaline earth metal oxide, 0.8-5% of alkali metal oxide, 0.8-5% of zirconium oxide, 0.4-2% of zinc oxide and 0.4-2% of di-phosphorus pentoxide. The raw material is crushed, ground and grinded, and the high-silicon aluminum precursor particles prepared by the physical method, the chemical method or the method combining the physical method and the chemical method are pretreated, high-temperature spheroidized and surface-coated, so that the high-temperature-resistant anti-degradation spherical additive product is prepared. The product has the excellent performances of high sphericity, good fluidity, small friction resistance, easy mixing and uniformity, simple use and the like; the high-temperature-resistant anti-degradation is obvious under the well condition that the bottom hole static temperature is 150-300 DEG C, and the cement stone strength is obviously improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cement slurry functional additive materials for well cementing, and particularly relates to a preparation method of a high-temperature-resistant anti-degradation spherical additive for oil and gas resource exploitation, which is mainly applied to the field of oil and gas resource exploitation and is particularly suitable for well cementing operation of high-temperature wells with a well bottom static temperature of 150-300 DEG C in deep, ultra-deep (more than 10,000 meters) and complex reservoir oil and gas resources. BACKGROUND

[0002] Petroleum, natural gas and other energy resources are the blood of the national industry, and are related to social stability and people's livelihood. China is relatively rich in oil and gas resources, mainly concentrated in the Tarim Basin, Sichuan Basin, Songliao Basin, Junggar Basin, Qaidam Basin and Bohai Bay regions, among which more than 34% are in deep, ultra-deep and complex reservoirs, and the downhole environment is in a high temperature and high pressure state, which puts higher requirements on well cementing technology and materials.

[0003] As the most commonly used cementitious material in well cementing processes at home and abroad, the silicate cement system has the advantages of low cost and wide applicability. However, when the curing temperature of conventional silicate cement stone is above 110 DEG C, the hydration product changes from amorphous C-S-H gel to alpha-C2SH crystal, resulting in strength degradation. With the exploitation of deep, ultra-deep reservoir oil and gas resources, the strength degradation, poor high-temperature stability, cracking and shrinkage of cement stone become more and more obvious when the well bottom static temperature is above 150 DEG C, especially when the temperature is above 200 DEG C, which leads to the failure of the interlayer isolation of the cement sheath and becomes a major problem restricting the exploitation of oil and gas resources.

[0004] In order to solve the problems caused by high temperature at the well bottom, such as strength degradation, current technical personnel introduce silica sand (or microsilica, silicon powder, etc.) as the main high-temperature anti-degradation material, which improves the high-temperature stability of the cement stone to some extent, but the cement stone still has obvious degradation. When the well bottom temperature is above 150 DEG C, the effect of slowing down the degradation of the cement stone is continuously weakened, especially when the temperature is above 200 DEG C, the anti-degradation effect is almost lost. In the article "Deep Ultra-High Temperature Cement Slurry Formulation and Its Strength Degradation Mechanism" published in Natural Gas Industry, Vol. 43, No. 7, July 2023, it is pointed out that a high proportion of silica sand will produce more amorphous C-S-H gel hydration product when the curing temperature is 200 DEG C, which will help to improve the short-term strength of the cement stone, but will lead to accelerated long-term strength degradation.

[0005] To this end, the technical staff carried out a lot of technical research and innovation, hoping to develop long-term anti-decay materials or anti-decay high-temperature cementing slurry system for high-temperature well cementing operation at well bottom static temperature above 150℃ or even above 200℃, to solve the technical problem of continuous decay of cement stone within 42 days. At present, the oil and gas resource exploitation site requires that the cement stone should have high temperature resistance under high temperature conditions. For example, Chinese patent CN108751753B discloses “high-temperature cementing cement and high-temperature cementing cement slurry”. The mineral composition of the cement clinker includes tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite and other components. After curing at 150-300℃ for 7 days, strength decay phenomenon occurs, and anti-decay phenomenon is not obvious. Chinese patent CN112939527B discloses “a super high strength and toughness cementing slurry system for well cementing and its preparation and application”. One or more of superfine cement, superfine silica powder, quartz sand and metakaolin are used as high-temperature reinforcing materials, and one or more of whiskers and fibers are used as inorganic toughening materials. The short-term strength is tested after curing at 120℃, 150℃ and 180℃ for 7 days, but the strength after curing for more than 28 days is not tested, and the test above 180℃ cannot be carried out, so it cannot be shown whether it has high-temperature anti-decay performance. Chinese patent CN105778876B discloses “an anti-high-temperature strength decay agent suitable for thermal recovery cement”. The anti-high-temperature anti-decay agent is mixed by different mesh sizes of quartz sand (200 mesh, 400 mesh, 600 mesh, 800 mesh, 1000 mesh), microsilica, expanded perlite, fly ash, diatomite, early strength activator and dispersant in a certain proportion, and the strength of the cement stone is tested after curing at 120℃, 160℃, 200℃, 240℃, 280℃, 320℃ and 360℃ for 7 days. There is still a decay phenomenon, which cannot meet the long-term anti-decay needs of the cement stone; and the types of quartz sand and other raw materials are complex, and the convenience of use is poor. Chinese patent CN110563428B discloses “a cementing cement for ultra-high temperature deep well and its preparation method and application”. The first anti-strength decay agent is silicon powder, and the second anti-strength decay agent is selected from one or more of aluminum oxide, aluminum hydroxide, zinc oxide, zinc hydroxide and strontium chloride. The method is cured at a temperature of 200℃-240℃, and the decay rate of the 28-day strength compared with the 2-day strength is close to 15%, and the strength decay phenomenon is obvious. Chinese patent CN115353868B discloses “an anti-high-temperature strength decay material for well cementing and a preparation method thereof”. The anti-high-temperature strength decay material is composed of lithium slag, aerated concrete waste, ceramic waste and carbon powder. The method is tested under the conditions of 230℃ and 250℃ for 28 days, but the strength change of the cement stone for a longer time is not tested; and the lithium slag, aerated concrete waste and ceramic waste materials mentioned in the patent are not conventional market products, and the stability of the above-mentioned materials cannot be continuously ensured during the well cementing process, which has strong limitations.

[0006] In order to solve the above problems, the application takes materials or minerals containing components such as silicon, aluminum, calcium, magnesium, boron, lithium, sodium, potassium, zinc, phosphorus, zirconium and the like as main raw materials, and prepares a high-temperature-resistant anti-degradation spherical additive for oil and gas resource exploitation through high-temperature melting and spheroidizing technology, and the surface is coated by a high-temperature modifier, and finally applied to a cement slurry system for well cementing. The prepared high-temperature-resistant anti-degradation spherical additive has high sphericity, good fluidity, small frictional resistance, easy mixing uniformity, simple use and the like; under the well condition that the bottom hole static temperature is 150-300 DEG C, the cement stone strength does not degrade, and the cement stone strength is significantly improved. SUMMARY

[0007] The application aims at the technical problems of the existing oil and gas resource exploitation well cementing materials, such as serious high-temperature strength degradation, accelerated long-term strength degradation, poor high-temperature stability, cracking shrinkage and poor use convenience, and provides a preparation method of a high-temperature-resistant anti-degradation spherical additive for oil and gas resource exploitation, so as to solve the problem of long-term strength degradation of the cement stone in the high-temperature well cementing operation process under the bottom hole static temperature of 150-300 DEG C, and meet the needs of deep and ultra-deep reservoir oil and gas resource exploitation.

[0008] In order to achieve the above-mentioned purpose, the preparation method of the high-temperature-resistant anti-degradation spherical additive for oil and gas resource exploitation is implemented by the following steps:

[0009] S1: Preparation of precursor particles

[0010] The raw materials are accurately weighed according to the raw material formula composition, crushed, ground to a particle size of less than 30 μm, mixed and granulated to prepare high-silicon aluminum precursor particles with a particle size of ≤200 μm and a porosity of ≤2%, so as to ensure that the high-temperature-resistant anti-degradation spherical additive meeting the particle size and density requirements can be prepared in the subsequent steps; the granulation can be performed by one of wet granulation, dry granulation, adhesive granulation, fluidized bed granulation, dry granulation and the like, if the particles are too large, they can be sorted out by a vibrating screen, a classifier and the like, and the materials are re-granulated; if the porosity does not meet the requirements, the materials can also be crushed, ground and then granulated, so as to improve the utilization rate of raw materials and reduce waste. The reasonable particle size range of the granulated particles is preferably between 2-200 μm.

[0011] When the sum of the mass of each component in the raw material is calculated as 100%, the content of each component is: 40-55% of silicon dioxide, 35-50% of aluminum oxide, 1.2-5% of boron oxide, 1.8-5% of alkaline earth metal oxide, 0.8-5% of alkali metal oxide, 0.8-5% of zirconium oxide, 0.4-2% of zinc oxide and 0.4-2% of phosphorus pentoxide.

[0012] S2: Pretreatment of precursor particles

[0013] The high-silicon aluminum precursor particles prepared in S1 are pretreated by physical, chemical or combined methods to achieve optimal fluidity, so that they can be uniformly dispersed in the subsequent high-temperature spheroidization step and form individual particles after high-temperature spheroidization, while improving the efficiency of heat transfer in the furnace.

[0014] S3: High-temperature spheroidization of precursor particles

[0015] After the high-silicon aluminum precursor particles prepared in S2 are mixed with combustion-supporting gas, the material is sent into a high-temperature spheroidization furnace with a temperature of 1300-1600°C by pneumatic conveying. After high-temperature melting, the high-silicon aluminum precursor particles form a glass melt, which is rapidly cooled to form a spherical additive with a particle size of ≤200 μm, a strength of 50-150 MPa, and a density of 2.0-2.8 g / cm 3 The prepared spherical additive is a high-silicon aluminum glass material that can slowly react with cement stone, avoiding the phenomenon of high early strength and weak late strength or growth caused by the violent reaction of ordinary anti-degradation agents or anti-strength degradation agents.

[0016] S4: Surface coating treatment of spherical additives

[0017] The spherical additive obtained in S3 is coated with a high-temperature resistant surface treatment agent that can withstand a temperature of 150-300°C, resulting in a high-temperature resistant anti-degradation spherical additive product with a particle size of ≤200 μm, a compressive strength of 50-150 MPa, and a density of 2.0-2.8 g / cm 3 , which can prevent the strength degradation of cement stone at a temperature of 150-300°C. Through surface coating treatment, the combination ability with cement slurry is improved, and the reaction speed with cement slurry or cement stone at high temperatures is delayed.

[0018] Further, in S2, the physical method is to remove the water on the surface of the high-silicon aluminum precursor particles at a temperature of 80-150°C, or to impart the same charge to the surface of the high-silicon aluminum precursor particles by electrodes to achieve mutual repulsion between particles. The combination of the above two methods and other physical treatment methods that can achieve optimal fluidity can also be used.

[0019] In the S2 step, the chemical method is to select a surface treatment agent to modify or coat the high-silicon aluminum precursor particles, and then use a drying device to dry at 80-150°C, so that the particles are fully coated and have good flowability. The selected surface treatment agent is one or more of silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconium aluminate coupling agent, surfactant, organosilicon, unsaturated organic acid and organic oligomer, superdispersant, water-soluble polymer, and inorganic surface modifier, and the addition amount is 0.25%-0.6% of the mass of the high-silicon aluminum precursor particles.

[0020] Of course, in the S2 step, to achieve the best flowability of the high-silicon aluminum precursor particles, a combination of physical and chemical methods can also be used.

[0021] Further, the silicon dioxide is selected from mineral materials with a silicon dioxide content of ≥90% in quartz, cristobalite or quartz sand, or chemically prepared silicon sol, white carbon black materials meeting the corresponding national standards.

[0022] Further, the aluminum oxide is selected from bauxite, bauxite, hard bauxite, high-aluminum mineral materials meeting the corresponding national standards, or artificially synthesized aluminum oxide materials meeting the corresponding national standards.

[0023] Further, the boron trioxide is one, two or three of borax, boric acid, boron sand, or any combination thereof meeting the corresponding national standards.

[0024] Further, the alkaline earth metal oxide is one, two or three of calcium oxide, magnesium oxide, strontium oxide, or any combination thereof; the alkali metal oxide is one, two or three of lithium oxide, sodium oxide, potassium oxide, or any combination thereof.

[0025] Further, in the S1 step, the crushing mill uses one of a roller mill or a ball mill, or the crushing mill uses one of a roller mill or a ball mill, or uses a jaw crusher or a cone crusher in combination with one of a roller mill or a ball mill; the grinding uses one of a cage mill, a roller mill, a rod mill or a Raymond mill, or a combination of any two.

[0026] Further, in the S3 step, the combustion-supporting gas is air, oxygen or a mixture of the two required for fuel combustion, and the fuel is one or a combination of coal powder, coal gas, natural gas or petroleum gas. The combustion-supporting gas and fuel are mixed and burned to produce high temperature and provide heat energy.

[0027] Further, in the S4 step, the high-temperature resistant surface treatment agent is one or a mixture of two or more of aluminate coupling agent, zirconium aluminate coupling agent, surfactant, unsaturated organic acid and organic oligomer, hyperdispersant, water-soluble polymer, and inorganic surface modifier, and the applicable temperature is 150-300 DEG C. The use of the above surface treatment agent can improve the interfacial bonding force between the spherical additive and the cement paste or cement stone, improve the early strength of the cement stone, delay the direct contact between the cement paste or cement stone and the spherical additive, and has a time-delay effect, and finally, the surface treatment method can slow down the release rate of ions on the surface of the spherical additive.

[0028] In the S3 step, the combustion-supporting gas can be used as a carrier for pneumatic conveying, in the form of suction or pressure or a combination of the two methods, to fully mix the high-silicon aluminum precursor particles with the combustion-supporting gas to ensure heat transfer of the precursor particles, thereby rapidly melting to form a glass melt.

[0029] In the S3 step, the rapid cooling refers to rapidly reducing the temperature of the glass melt to below the glass softening point, which can be calculated according to the composition of the spherical additive, and can be determined by referring to related glass preparation process technology or laboratory test.

[0030] In actual use, the silica and alumina raw materials can be selected from solid waste such as waste glass and waste ceramic with high Si and Al content. Among them, the waste glass is preferably borosilicate glass, because the borosilicate glass is based on SiO2, B2O3 and alkali metal oxide as the basic component, has good thermal stability, chemical stability and mechanical strength, and other advantages, and is widely used due to its wide raw material sources, strong element inclusion, easy forming and other characteristics.

[0031] The present application adds di boron trioxide to the raw materials, which can form a boron-oxygen tetrahedral three-dimensional network structure or a boron-oxygen three-dimensional network structure, has the effect of reducing the glass melting temperature, and forming a borosilicate glass network structure. At the same time, the "B-O" bond strength is high, which can improve the mechanical strength, impact resistance and anti-cracking ability of borosilicate glass.

[0032] The effects of adding alkali metal oxide, alkaline earth metal oxide, zinc oxide, zirconium oxide and phosphorus pentoxide to the raw materials are as follows:

[0033] Alkali metal oxide: is a common component in borosilicate glass, which has excellent fluxing characteristics, and the presence of alkali earth metal cations can balance the negative charge and reduce the generation of defects in the glass. There is a mixed alkali effect between the two alkali earth metal oxides, and the use of two or more alkali earth metal oxides can maximize the improvement of the physical properties of the glass.

[0034] Alkaline earth metal oxide: is a common component in borosilicate glass, which has excellent fluxing characteristics, avoids the phase separation of glass melt, reduces the viscosity and melting point of glass, thereby reducing the energy consumption of borosilicate glass preparation process and improving the forming efficiency.

[0035] Zinc oxide: a small amount of zinc oxide is introduced into borosilicate glass to form zinc-oxygen octahedral coordination, so that the glass structure is more dense, thereby improving the physical properties such as wear resistance and high-temperature stability of the glass material.

[0036] Zirconium oxide: a small amount of zirconium oxide can be introduced into borosilicate glass to significantly enhance the physical properties such as hardness and hardness of the glass.

[0037] Phosphorus pentoxide: can form phosphorus-oxygen tetrahedral structure, and a small amount of phosphorus pentoxide can be introduced into borosilicate glass to significantly improve the compatibility of other components in borosilicate glass and reduce the phase separation of glass melt.

[0038] More importantly, the synergistic effect brought by the superposition and fusion of the above components makes the high-temperature-resistant and anti-degradation spherical adjuvant prepared by the method of the present application completely solve the technical problem of long-term strength degradation of cement stone in the cementing operation process of high-temperature oil and gas wells with bottom hole static temperature of 150-300℃, and meet the demand of deep and ultra-deep reservoir oil and gas resource exploitation.

[0039] Compared with the prior art, the preparation method of the high-temperature-resistant and anti-degradation spherical adjuvant for oil and gas resource exploitation has the following beneficial effects:

[0040] (1) Industrial products, mineral materials or solid wastes are used as main raw materials, the raw materials used have the advantages of environmental friendliness, wide source and low cost, and the high-value-added utilization of waste glass, waste ceramics and other solid wastes can be realized, which is conducive to the large-scale popularization and use of the material in the field of oil and gas resource exploitation.

[0041] (2) The prepared high-temperature-resistant anti-degradation spherical additive product contains 40-55% silicon dioxide, 35-50% aluminum oxide, 1.2-5% boron trioxide, 1.8-5% alkaline earth metal oxide, 0.8-5% alkali metal oxide, 0.8-5% zirconium oxide, 0.4-2% zinc oxide, and 0.4-2% diphosphorus pentoxide. Through formula optimization, the spherical additive forms a micro glass network structure with silicon dioxide and aluminum oxide as the framework, improving the structural compactness and high-temperature stability of the spherical additive; meanwhile, the spherical additive contains a large amount of aluminum oxide, and the proportion of calcium oxide is controlled within 5%, which can form hydrated products such as tobermorite and xonotlite with high thermal stability at high temperatures, significantly reducing the amount of amorphous C-S-H gel produced due to the increase of the calcium-silicon ratio in the hydration reaction, thereby reducing the generation of α-C2SH crystals with large voids and poor strength from amorphous C-S-H gel, and solving the problem of long-term strength degradation of cement stone under high-temperature conditions of 150-300°C.

[0042] (3) The precursor particles are pretreated by physical or chemical methods to achieve optimal fluidity. Due to the small particle size and large specific surface area of the precursor particles, the particle surface is in an unstable energy state and is prone to agglomeration. This method uses physical or chemical methods to reduce the proportion of easily water-absorbing groups such as hydroxyl groups on the surface, or to reduce the contact area and time of easily water-absorbing groups such as hydroxyl groups with water molecules in the form of surface coating, or to give the same charge to the surface to generate electrostatic repulsion, thereby making the particles have excellent fluidity and dispersibility, avoiding the adhesion between particles; and compared with untreated particles, the processing amount of precursor particles per unit time during the high-temperature spheroidization process is greatly improved, saving the industrialization time cost.

[0043] (4) In the high-temperature spheroidization process of the precursor particles, the particles are prepared into spherical glassy micron-sized spherical particles. Compared with ordinary anti-degradation agents or strength degradation resistance agents, the spherical additive belongs to glass material with low surface activity and more stable physicochemical properties, and can continuously and slowly react with cement stone under high-temperature conditions of 150-300°C, solving the phenomenon of high early strength and declining later strength caused by the violent reaction of ordinary anti-degradation agents or strength degradation resistance agents, and continuously improving the long-term strength of cement stone. The particles form perfect micron-sized spherical particles after high-temperature melting, and have excellent fluidity, easy mixing with cement, good cement paste fluidity, small frictional resistance, reduced casing wear, excellent anti-gas channeling performance, effective zonal isolation, easy plugging of small pores on the filter cake surface, and low fluid loss, etc.

[0044] (5) The high-temperature surface treatment agent is selected to perform surface treatment on the prepared spherical additive, so that the effective components of the cement and the spherical additive are better combined through specific surface functional groups, the interfacial bonding force between the spherical additive and the cement paste or cement stone is significantly improved, and the early strength of the cement stone is increased by 20-45% compared with when the surface treatment is not performed. Meanwhile, the high-temperature surface treatment agent can withstand a high temperature of 300°C or above, can delay the direct contact between the cement paste or cement stone and the surface of the spherical additive, thereby reducing the speed of the hydration reaction between the cement paste or cement stone and the surface of the spherical additive; finally, the surface treatment method can slow down the precipitation speed of the ions on the surface of the spherical additive, and further slow down the degree of the cement hydration reaction caused by the ion precipitation. DETAILED DESCRIPTION

[0045] To describe the present application, the preparation method of the high-temperature resistant anti-degradation spherical additive for oil and gas resource exploitation of the present application will be further described in detail below in combination with examples. However, the present application is not limited to the examples.

[0046] Example 1

[0047] The specific implementation process is as follows:

[0048] Preparation of high-silicon aluminum precursor particles: according to the formula 1 in Table 1, each raw material is weighed, and each material is crushed by using a jaw crusher, and then the materials are mixed and put into a rod mill for grinding to obtain a mixture with a particle size D 100 of 28 μm; the mixture is granulated by using a dry granulator to obtain precursor particles with a particle size D 100 of 180 μm and a porosity of 1.5%.

[0049] Pre-treatment of precursor particles: the precursor particles prepared in step (1) are surface treated with methyltriethoxysilane at a mass fraction of 0.5% of the precursor particles, heated in a rotary kiln for 2 h, and the temperature is set to 120°C to complete the pre-treatment.

[0050] High-temperature spheroidization of precursor particles: the precursor particles prepared in step (2) are placed in a premixing tank, and the conventional air is used as the combustion-supporting gas and the gas for pneumatic conveying to fully mix the two, and then the mixture is sent into a high-temperature vitrification furnace with a temperature of 1300°C, the precursor particles are rapidly heated and melted into a glass melt, and then the glass melt is rapidly cooled to form spherical additives with a particle size D 100 of 180 μm, a compressive strength of 103 MPa, and a density of 2.2 g / cm 3 .

[0051] Surface high-temperature resistant treatment: a commercially available aluminate coupling agent is selected, and the mass fraction of the aluminate coupling agent is 0.8% of the mass of the spherical additive, the spherical additive prepared in step (3) is modified by wet method to coat a layer of aluminate coupling agent on the surface, and then the spherical additive is dried at 80°C by using a drying device to obtain spherical additives with a particle size D100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm 3 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm Example 2

[0052] The specific implementation process is as follows:

[0053] Preparation of high-silicon aluminum precursor particles: each raw material is weighed according to the formula 2 in Table 1, each material is crushed by using a roll crusher, and then each material is mixed and put into a ball mill for grinding to obtain a mixture with a particle size of 22 μm; the mixture is granulated by using a wet granulation method to obtain precursor particles with a particle size of 150 μm and a porosity of 1.2%. 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm

[0054] Pre-treatment of precursor particles: the precursor particles prepared in step (1) are surface treated with isopropoxy trititanate at a mass fraction of 0.3% of the precursor particles, and the pre-treatment is completed by heating in an oven for 3 h at a temperature of 90°C.

[0055] High-temperature spheroidization of precursor particles: the precursor particles prepared in step (2) are placed in a premixing tank, and 90% conventional air and 10% pure oxygen are fully mixed as combustion-supporting gas and gas for pneumatic conveying, and then the mixture is sent into a high-temperature spheroidization furnace at a temperature of 1400°C, the precursor particles are rapidly heated and melted into a glass melt, and then the glass melt is rapidly cooled to form a spherical additive with a particle size of 150 μm, a compressive strength of 103 MPa, and a density of 2.4 g / cm 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm 3 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm

[0056] Surface high-temperature resistant treatment: a commercially available aluminum-zirconium coupling agent is selected, and the spherical additive prepared in step (3) is modified by dry method to coat a layer of aluminum-zirconium coupling agent on the surface, and then the spherical additive is dried at 95°C by using a drying device to obtain a high-temperature resistant anti-degradation spherical additive with a particle size of 150 μm, a compressive strength of 103 MPa, and a density of 2.4 g / cm 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm 3 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm Example 3

[0057] The specific implementation process is as follows:

[0058] Preparation of high-silicon aluminum precursor particles: each raw material is weighed according to the formula 3 in Table 1, each material is crushed by using a ball mill, and then each material is mixed and put into a ball mill for grinding to obtain a mixture with a particle size of 10 μm; the mixture is granulated by using a dry granulation method to obtain precursor particles with a particle size of 90 μm and a porosity of 0.6%. 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm 100 a high-temperature resistant anti-degradation spherical additive with a particle size of 180 μm, a compressive strength of 82 MPa, and a density of 2.2 g / cm

[0059] Pre-treatment of precursor particles: the precursor particles prepared in step (1) are subjected to surface treatment using a low-temperature plasma device to make their surfaces carry the same electric charge and thus generate electrostatic repulsion, thereby obtaining precursor particles with excellent fluidity.

[0060] High-temperature spheroidization of precursor particles: the precursor particles prepared in step (2) are placed in a premixing tank, and after being fully mixed with 70% regular air and 30% pure oxygen as combustion-supporting gas and gas for pneumatic conveying, they are fed into a high-temperature vitrification furnace with a temperature of 1500°C, the precursor particles are rapidly heated and melted into a glass melt, and then rapidly cooled to form spherical additives with a particle size D 100 of 90 μm, a compressive strength of 124 MPa, and a density of 2.6 g / cm 3 .

[0061] Surface high-temperature resistance treatment: commercially available polybutene dioic acid is selected, and 0.5% of the mass of the spherical additives prepared in step (3) is weighed, and the spherical additives are modified by dry method to coat a layer of polybutene dioic acid on their surfaces, and after drying at 110°C using a drying device, spherical additives with a particle size D 100 of 90 μm, a compressive strength of 124 MPa, and a density of 2.6 g / cm 3 with high-temperature resistance and anti-degradation are prepared. Example 4

[0062] The specific implementation process is as follows:

[0063] Preparation of high-silicon aluminum precursor particles: the raw materials are weighed according to the formula 3 in Table 1, and the various materials are crushed using a roller crusher, and then the materials are mixed and sequentially put into a rod mill and a ball mill for grinding, thereby obtaining a mixture with a particle size D 100 of 5 μm; the mixture is granulated by a dry granulation method, thereby obtaining precursor particles with a particle size D 100 of 60 μm and a porosity of 0.4%.

[0064] Pre-treatment of precursor particles: the precursor particles prepared in step (1) are subjected to surface treatment using a low-temperature plasma device to make their surfaces carry the same electric charge and thus generate electrostatic repulsion, thereby obtaining precursor particles with excellent fluidity.

[0065] High-temperature spheroidization of precursor particles: the precursor particles prepared in step (2) are placed in a premixing tank, and after being fully mixed with 70% regular air and 30% pure oxygen as combustion-supporting gas and gas for pneumatic conveying, they are fed into a high-temperature vitrification furnace with a temperature of 1500°C, the precursor particles are rapidly heated and melted into a glass melt, and then rapidly cooled to form spherical additives with a particle size D 100 of 90 μm, a compressive strength of 124 MPa, and a density of 2.6 g / cm 3spherical aid.

[0066] Surface high temperature resistant treatment: select commercially available graft copolymer type super dispersant, take 0.6% of the mass of the spherical aid, wet modification of the spherical aid prepared in step (3) to make its surface coated with a layer of graft copolymer type super dispersant, drying equipment at 150℃, after drying, the particle size D 100 of 60μm, compressive strength of 150MPa, density of 2.8g / cm 3 of high temperature resistant anti-degradation spherical aid. Example 5

[0067] The specific implementation process is as follows:

[0068] Preparation of high-silicon aluminum precursor particles: according to the formula 3 in table 1, weigh each raw material, use a roller crusher to crush each material, then put each material into a rod mill and a ball mill for grinding, and prepare a mixture material with a particle size D 100 of 5μm; use the adhesion granulation method to granulate the mixture material, and prepare precursor particles with a particle size D 100 of 170μm and a porosity of 0.7%.

[0069] Pre-treatment of precursor particles: use 0.5% of the mass of the precursor particles of polydimethylsiloxane to treat the precursor particles prepared in step (1), heat in an oven for 2h, and set the temperature to 130℃ to complete the pre-treatment.

[0070] High-temperature spheroidization of precursor particles: put the precursor particles prepared in step (2) into a premixing tank, mix with pure oxygen as combustion-supporting gas and gas for pneumatic conveying, and then send into a high-temperature spheroidization furnace with a temperature of 1600℃, so that the precursor particles are rapidly heated and melted into a glass melt, and then rapidly cooled to form spherical aid with a particle size D 100 of 170μm, a compressive strength of 150MPa, and a density of 2.7g / cm 3 .

[0071] Surface high temperature resistant treatment: select commercially available graft copolymer type super dispersant, take 0.6% of the mass of the spherical aid, wet modification of the spherical aid prepared in step (3) to make its surface coated with a layer of graft copolymer type super dispersant, drying equipment at 150℃, after drying, the particle size D 100 of 170μm, a compressive strength of 150MPa, and a density of 2.7g / cm 3 of high temperature resistant anti-degradation spherical aid.

[0072] The process steps of example 6 are the same as those of example 4, and finally D 100 of 70μm, a compressive strength of 165MPa, and a density of 2.7g / cm3 high-temperature resistant anti-degradation spherical additives.

[0073] The process steps of Example 7 are the same as those of Example 1, and finally the particle size D 100 is 170 μm, the compressive strength is 110 MPa, the density is 2.4 g / cm 3 high-temperature resistant anti-degradation spherical additives.

[0074] The high-temperature resistant anti-degradation spherical additives prepared by the method have been tested in cementing operations of a high-temperature well for exploitation of super-deep oil and gas resources of more than ten thousand meters, and the bottom hole static temperature is as high as 230-300 DEG C. The test research shows that the problem of long-term strength degradation of cement stone is completely solved by using the high-temperature resistant anti-degradation spherical additives prepared by the method.

[0075] Table 1 shows the mass fraction of each component in Examples 1-7

[0076]

Claims

1. A method for preparing a high temperature resistant and anti-fading spherical additive for oil and gas resource exploitation, characterized in that Use the following steps to implement: S1: Preparation of precursor particles The raw materials are accurately weighed according to the raw material formula, crushed and ground to a particle size of less than 30 μm, and then premixed and granulated to obtain high-silicon-aluminum precursor particles with a particle size of ≤200 μm and a porosity of ≤2%; The content of each component in the raw material when the sum of the mass of each component is calculated as 100% is: silicon dioxide 40-55%, aluminum oxide 35-50%, boron trioxide 1.2-5%, alkaline earth metal oxide 1.8-5%, alkali metal oxide 0.8-5%, zirconium oxide 0.8-5%, zinc oxide 0.4-2%, phosphorus pentoxide 0.4-2%; S2: Precursor particle pretreatment Pre-treating the high-silicon-aluminum precursor particles prepared in step S1 by physical methods, chemical methods, or a combination of the two, so that their fluidity reaches an optimal state; S3: High temperature spheroidization of precursor particles After the high-silicon-aluminum precursor particles prepared in step S2 are fully mixed with the combustion-supporting gas, the materials are pneumatically conveyed into a high-temperature vitrification furnace at a temperature of 1300~1600℃. After the high-silicon-aluminum precursor particles are melted into a glass melt at high temperature, they are rapidly cooled to form a glass with a particle size of ≤200μm, a strength of 50~150MPa, and a density of 2.0~2.8g / cm 3 Spherical additives; S4: Surface coating treatment of spherical additives The spherical additive obtained in step S3 is coated with a high temperature resistant surface treatment agent that can withstand high temperature conditions of 150-300°C to obtain a particle size of ≤200μm, a compressive strength of 50-150MPa, and a density of 2.0-2.8g / cm 3 , a high-temperature resistant and anti-degradation spherical additive product that can prevent the strength decline of cement stone at 150~300℃.

2. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: In step S2, the physical method is to fully remove the moisture on the surface of the high-silicon-aluminum precursor particles at 80~150°C, or to give the same charge to the surface of the high-silicon-aluminum precursor particles through electrodes to achieve the effect of mutual repulsion between particles.

3. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: In step S2, the chemical method is to perform surface modification or coating treatment on the high-silicon-aluminum precursor particles using a selected surface treatment agent.

4. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 3, wherein: The selected surface treatment agent is one or more of silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconium aluminate coupling agent, surfactant, organosilicon, unsaturated organic acid and organic oligomer, hyperdispersant, water-soluble polymer, and inorganic surface modifier, and the added amount is 0.25% to 0.6% of the mass of the high-silicon-aluminum precursor particles.

5. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: The silicon dioxide is selected from mineral materials with a silicon dioxide content of ≥90% in tridymite, cristobalite or quartz sand, or silica sol and white carbon black materials prepared by chemical methods and meeting corresponding national standards.

6. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: The aluminum oxide is selected from bauxite, bauxite, diaspore and other high-aluminum mineral materials that meet the corresponding national standards, or artificially synthesized alumina materials that meet the corresponding national standards.

7. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: The boron trioxide is one, two or any combination of three of borax, boric acid and boron ore sand that meet the corresponding national standards.

8. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: The alkaline earth metal oxide is one, two or a combination of three of calcium oxide, magnesium oxide and strontium oxide; the alkali metal oxide composition is one, two or a combination of three of lithium oxide, sodium oxide and potassium oxide.

9. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, wherein: In step S1, the crushing is performed by using one of a roller mill and a ball mill, or a jaw crusher or a cone crusher is used in combination with one of a roller mill and a ball mill; the grinding is performed by using one of a cage mill, a roller mill, a rod mill or a Raymond mill, or a combination of any two of them.

10. The method for preparing the high-temperature resistant and anti-fading spherical additive for oil and gas resource exploitation according to claim 1, characterized in that: In step S3, the combustion-supporting gas is air, oxygen, or a mixture of the two required for fuel combustion; in step S4, the high-temperature resistant surface treatment agent is one or a mixture of two or more of aluminate coupling agent, zirconium aluminate coupling agent, surfactant, unsaturated organic acid and organic oligomer, hyperdispersant, water-soluble polymer, and inorganic surface modifier, and the applicable temperature is 150~300℃.

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