A wear-resistant high-strength lightening agent for drilling fluid and a preparation method thereof

Abstract

The application discloses a kind of drilling fluid wear-resistant high-strength lightening agent and preparation method thereof, when the sum of raw material components is calculated as 100%, the mass content of each component is: 65-75% of silicon dioxide, 5-10% of aluminum oxide, 5-10% of boron oxide, 5-10% of alkaline earth metal oxide, 5-10% of alkali metal oxide, 0.2-3% of rare earth elements, 0-2% of iron trioxide, 0-2% of manganese dioxide, 0-2% of zirconium oxide, 0-2% of zinc oxide, 0.2-5% of other trace element materials. All components are crushed, ground, granulated and treated to prepare precursor particles; the precursor particles are pretreated, high-temperature hollow spheroidized, and then surface treated to prepare the drilling fluid wear-resistant high-strength lightening agent. The product has the advantages of environmental friendliness, obvious density reduction effect, lubrication and drag reduction, no loss of MWD signal, etc., and solves the problems of low pressure strength, easy breakage and poor wear resistance of existing low-density hollow glass microsphere lightening agent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high-temperature resistant additive materials for drilling fluid and cement slurry in the process of oil and gas resource drilling and completion, and particularly relates to a wear-resistant high-strength lightening agent for drilling fluid and a preparation method thereof, which is mainly applied to the field of oil and gas resource exploitation. 3 The present application belongs to the field of high-temperature resistant additive materials for drilling fluid and cement slurry in the process of oil and gas resource drilling and completion, and particularly relates to a wear-resistant high-strength lightening agent for drilling fluid and a preparation method thereof, which is mainly applied to the field of oil and gas resource exploitation. 3 The present application belongs to the field of high-temperature resistant additive materials for drilling fluid and cement slurry in the process of oil and gas resource drilling and completion, and particularly relates to a wear-resistant high-strength lightening agent for drilling fluid and a preparation method thereof, which is mainly applied to the field of oil and gas resource exploitation. BACKGROUND

[0002] Traditional low-density drilling fluid is mainly oil-based drilling fluid, aerated drilling fluid or foam drilling fluid. Among them, the drilling fluid with a density of 0.85-1.00 g / cm 3 has the most oil-based drilling fluid. Although this system drilling fluid has the advantages of good flowability, strong temperature resistance, low density, etc., it also has the unavoidable disadvantages of serious environmental pollution, high cost, and being not conducive to logging operation. The drilling fluid with a density lower than 0.85 g / cm 3 is mainly aerated drilling fluid or foam drilling fluid, which has the advantages of low density, wide adjustable range, good leak-off prevention ability, etc. However, because it uses gas as a lightening agent, the gas has the disadvantages of compressibility, serious pulse signal attenuation, limitation of MWD technology, etc., and also causes problems such as corrosion of drilling tools, complex hydraulic calculation, high friction coefficient, etc., which limits its application range. Therefore, it is of great significance to develop a lightening agent for drilling fluid that is environmentally friendly, has low density, strong temperature resistance, is incompressible, and is suitable for MWD technology.

[0003] As a multifunctional lightening agent developed in recent years, hollow glass microspheres are widely used in cement slurry due to their hollow, lightweight, compression-resistant, high-strength and other excellent properties, which has effectively promoted the progress of cementing technology in China. In the early 21st century, relevant technical personnel also began to try to use hollow glass microspheres as a lightening agent to prepare low-density drilling fluid, and carried out several field tests, which verified that the hollow glass microspheres as a lightening agent to prepare drilling fluid have the advantages of environmental friendliness, obvious density reduction effect, lubrication and drag reduction, no loss of MWD signal, etc. However, due to the large amount of crushing of hollow glass microspheres, the flowability is poor, the viscosity is increased, and the cost is increased, which makes it impossible to be used as a lightening agent for low-density drilling fluid system.

[0004] In order to solve the problems existing in traditional low-density drilling fluid or weight reducer, the skilled in the art has carried out a lot of technical research and innovation, hoping to develop an environmentally friendly, low-density, lubricating, MWD signal loss-free, stable performance, low-cost weight reducer or low-density drilling fluid system for low-pressure oil and gas reservoir drilling and completion process. For example, Chinese patent CN105086952B discloses a "drilling fluid weight reducer and its preparation method", wherein the hollow glass microsphere surface of the water drilling fluid weight reducer is coated with a polymer layer resistant to 90℃ temperature condition, the hollow glass microspheres used only resist 28MPa pressure, and the polymer layer only resists 40MPa pressure after coating. The prepared drilling fluid density is >0.95g / cm 3 , and the applicability is poor. Chinese patent CN115432921A (under review) discloses a "hollow glass microsphere for drilling fluid density reducer and its production method", wherein the reducer is hollow glass microspheres, but the density of the prepared reducer is only 0.38~0.60g / cm 3 , and the density adjustment range of the drilling fluid is limited, and it does not provide a solution to the problems of drill tool wear and cement slurry flowability. Chinese patent CN103666407B discloses a "drilling fluid and its preparation method", which uses lightweight high polymer hollow microspheres as a weight reducer, which is easy to pollute the environment. At the same time, due to its certain elasticity and deformability, it is easy to change under certain pressure conditions, causing drilling fluid density fluctuations, pulse signal attenuation and other problems.

[0005] In view of the above technical problems, the present application uses materials or minerals containing silicon, aluminum, boron, alkali metal oxides, alkaline earth metal oxides, rare earth elements, iron, manganese, zirconium, zinc and other elements as main raw materials, and forms precursor particles by physical or chemical methods, and makes them hollow by high-temperature spheroidization technology of powder, to prepare a drilling fluid wear-resistant high-strength weight reducer, and modify it by surface modification process, and apply it to low-density cement slurry and drilling fluid in oil and gas resource exploitation process, especially suitable for low-density drilling fluid, with the advantages of safety, environmental protection, obvious density reduction effect, adjustable density, good stability under high temperature and high pressure, low drill tool wear, improved mud cake quality, low filtration loss, good flowability, no loss of MWD signal, low cost, etc. SUMMARY

[0006] The present application aims at the problems of the conventional oil-based low-density drilling fluid, such as serious environmental pollution, high cost, and adverse to mud logging operation, and the technical problems of the aerated drilling fluid or foam drilling fluid, such as compressibility, serious pulse signal attenuation, limitation of the use of MWD technology, corrosion of drilling tools, complex hydraulic calculation, high friction coefficient, and the problems of the existing low-density hollow glass microsphere reducing agent, such as low compressive strength, easy to break, and poor wear resistance, and the problems of the high polymer microspheres, such as easy to deform, causing the density fluctuation of the drilling fluid and the attenuation of the pulse signal, and provides a wear-resistant high-strength reducing agent for drilling fluid. 3 The present application aims at the problems of the conventional oil-based low-density drilling fluid, such as serious environmental pollution, high cost, and adverse to mud logging operation, and the technical problems of the aerated drilling fluid or foam drilling fluid, such as compressibility, serious pulse signal attenuation, limitation of the use of MWD technology, corrosion of drilling tools, complex hydraulic calculation, high friction coefficient, and the problems of the existing low-density hollow glass microsphere reducing agent, such as low compressive strength, easy to break, and poor wear resistance, and the problems of the high polymer microspheres, such as easy to deform, causing the density fluctuation of the drilling fluid and the attenuation of the pulse signal, and provides a wear-resistant high-strength reducing agent for drilling fluid. 3 The present application aims at the problems of the conventional oil-based low-density drilling fluid, such as serious environmental pollution, high cost, and adverse to mud logging operation, and the technical problems of the aerated drilling fluid or foam drilling fluid, such as compressibility, serious pulse signal attenuation, limitation of the use of MWD technology, corrosion of drilling tools, complex hydraulic calculation, high friction coefficient, and the problems of the existing low-density hollow glass microsphere reducing agent, such as low compressive strength, easy to break, and poor wear resistance, and the problems of the high polymer microspheres, such as easy to deform, causing the density fluctuation of the drilling fluid and the attenuation of the pulse signal, and provides a wear-resistant high-strength reducing agent for drilling fluid.

[0007] The present application aims at the problems of the conventional oil-based low-density drilling fluid, such as serious environmental pollution, high cost, and adverse to mud logging operation, and the technical problems of the aerated drilling fluid or foam drilling fluid, such as compressibility, serious pulse signal attenuation, limitation of the use of MWD technology, corrosion of drilling tools, complex hydraulic calculation, high friction coefficient, and the problems of the existing low-density hollow glass microsphere reducing agent, such as low compressive strength, easy to break, and poor wear resistance, and the problems of the high polymer microspheres, such as easy to deform, causing the density fluctuation of the drilling fluid and the attenuation of the pulse signal, and provides a wear-resistant high-strength reducing agent for drilling fluid.

[0008] To achieve the above-mentioned object of the present application, the wear-resistant high-strength reducing agent for drilling fluid is prepared from the following components, and the mass content of each component is calculated based on 100% of the sum of the raw material components:

[0009] Silicon dioxide: 65-75%

[0010] Aluminum trioxide: 5-10%

[0011] Boron trioxide: 5-10%

[0012] Alkaline earth metal oxide: 5-10%

[0013] Alkali metal oxide: 5-10%

[0014] Rare earth elements: 0.2-3%

[0015] Iron trioxide: 0-2%

[0016] Manganese dioxide: 0-2%

[0017] Zirconium oxide: 0-2%

[0018] Zinc oxide: 0-2%

[0019] Other trace element materials: 0.2-5%.

[0020] Further, the content of each compound in the alkali earth metal oxide is 70-80% of calcium oxide, 10-25% of magnesium oxide and 0-15% of strontium oxide, calculated on the basis of 100%. The ratio makes full use of the difference in ion size of different alkali earth metal oxides, and enhances the wear resistance of the glass after high-temperature hollow sphere formation.

[0021] Further, the content of each compound in the alkali metal oxide is 70-80% of sodium oxide, 10-25% of potassium oxide and 0-10% of lithium oxide, calculated on the basis of 100%. The ratio makes full use of the mixed alkali effect and the difference in ion size of alkali metal ions, enhances the fluxing effect of alkali metal ions, and hinders ion migration in the glass by changing the microstructure of the glass after high-temperature hollow sphere formation, thereby improving the structural stability of the glass.

[0022] Further, the content of each compound in the rare earth element is 75-90% of the total content of cerium oxide and lanthanum oxide, 0-10% of yttrium oxide, 0-10% of neodymium oxide and 0-10% of scandium oxide, calculated on the basis of 100%. The ratio further prevents crystallization of the glass during high-temperature hollow sphere formation, and improves the thermal stability, hardness and wear resistance of the glass.

[0023] Further, the other trace element material is one or a mixture of two or more of tungsten oxide, vanadium oxide and phosphorus pentoxide.

[0024] The total content of the ferric oxide and manganese dioxide is not zero, which greatly improves the corrosion resistance and stability of the glass.

[0025] As a preferred embodiment of the present application, the other trace element material is one or a mixture of two or more of tungsten oxide, vanadium oxide and phosphorus pentoxide.

[0026] The above-mentioned formula of the present application uses materials or minerals containing silicon, aluminum, boron, alkali metal oxide, alkali earth metal oxide, rare earth element, iron, manganese, zirconium, zinc and other elements as main raw materials, and the raw materials are widely available.

[0027] The present application discloses a preparation method of a wear-resistant high-strength lightening agent for drilling fluid.

[0028] (1) Preparation of precursor particles

[0029] Each raw material component is accurately weighed according to the formula composition, and all components are pre-mixed, crushed and ground to a certain particle size, then granulated to prepare precursor particles with a particle size D50 of 20-40 μm; the precursor particles are subjected to physical classification treatment to control the particle size D90 of the precursor particles to be ≤60 μm, and the particles exceeding the particle size range can be sorted out by physical classification, and the material is re-granulated.

[0030] The granulation process can adopt one or more of wet granulation, dry granulation, adhesive granulation, fluidized bed granulation, dry granulation, etc. to prepare precursor particles with a particle size D50 of 20-40 μm.

[0031] (2) Precursor particle pretreatment

[0032] The precursor particles prepared in step (1) are subjected to drying treatment to reduce the water content to within 0.5%; then the precursor particles are pretreated by physical or chemical methods to reduce the agglomeration between fine particles, improve their flowability, facilitate the subsequent process of conveying, and can be uniformly dispersed in the high-temperature vitrification process, while improving the heat transfer efficiency of the particles.

[0033] (3) High-temperature hollow spheroidization of precursor particles

[0034] After the precursor particles prepared in step (2) are fully mixed with the combustion-supporting gas, the material and the combustion-supporting gas are sent into the mixing chamber by pneumatic conveying to mix with the fuel. The mixed precursor particles, combustion-supporting gas and fuel are passed into a high-temperature vitrification furnace with a temperature of 1000-1450°C; the particles are melted into a glass melt at high temperature, and under the action of surface tension, spherical shapes are formed, and the high-temperature mixed gas is wrapped inside. After the glass melt passes through the high-temperature forming zone, it is rapidly cooled to 400-600°C within 2 min, and then slowly cooled to room temperature over 1-4 h to form a wear-resistant high-strength lightweight agent with a density of 0.28-0.60 g / cm 3 , a particle size D50 of 20-40 μm, a particle size D90 of ≤60 μm, and a strength of 20-150 MPa;

[0035] (4) Lightweight agent surface treatment: a surface treatment agent is selected to perform surface treatment on the lightweight agent prepared in step (3) to obtain a lightweight agent with a wide matrix adaptability and strong interfacial bonding force, a density of 0.28-0.60 g / cm 3 , a particle size D50 of 20-40 μm, a particle size D90 of ≤60 μm, and a strength of 20-150 MPa.

[0036] The physical method is to use a corona charging machine or a Faraday charging machine to give the particle surface the same charge to achieve mutual repulsion, thereby achieving good flowability; the chemical method is to use a surface treatment agent to modify the surface of the dried precursor particles to avoid particle agglomeration and improve their flowability.

[0037] The surface treatment agent is any one of silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconium aluminate coupling agent, surfactant, organosilicon, unsaturated organic acid and organic oligomer, super dispersant, water-soluble polymer, inorganic surface modifier, or a mixture of two or more thereof.

[0038] In step (3), the combustion-supporting gas is air, oxygen or a combination of both, and the fuel is one or a combination of coal gas, natural gas or petroleum gas.

[0039] In step (4), the surface treatment agent is any one of silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconium aluminate coupling agent, surfactant, organosilicon, unsaturated organic acid and organic oligomer, super dispersant, water-soluble polymer, inorganic surface modifier, or a mixture of two or more thereof; and the surface treatment method is to first use inorganic surface modifier for surface treatment, and then use one or two of surfactant, unsaturated organic acid, dispersant and water-soluble polymer for surface modification. With this surface treatment mode, the wear resistance and impact resistance of the weight-reducing agent are improved, the interfacial bonding force between the weight-reducing agent and the drilling fluid is further improved, and the migration of metal ions is reduced.

[0040] The drilling fluid weight-reducing agent prepared by the application is an aluminum-boron-silicate hollow glass microsphere treated by a surface treatment agent, has low density, small particle size, high strength, good chemical stability, high mechanical strength, high temperature resistance and other excellent characteristics, and can be used to prepare low-density drilling fluid with a density of 0.8-1.0 g / cm 3 and low-density cement slurry with a density of 0.90-1.45 g / cm 3 The low-density drilling fluid prepared by the application has the advantages of environmental friendliness, obvious density reduction effect, lubrication and drag reduction, no loss of MWD signal, and solves the problems of low compressive strength, easy breakage and poor wear resistance of the existing low-density hollow glass microsphere weight-reducing agent, and further promotes the progress of low-density drilling fluid technology.

[0041] Compared with the prior art, the drilling fluid weight-reducing agent and the preparation method thereof have the following beneficial effects:

[0042] (1) The formula uses materials or minerals containing silicon, aluminum, boron, alkali metal oxides, alkaline earth metal oxides, rare earth elements, iron, manganese, zirconium, zinc and other elements as main raw materials, and the raw materials are widely available.

[0043] (2) Through formula optimization, the microspheres of the present invention have a microscopic glass network structure with a boron aluminum silicon skeleton, which improves the structural density and high-temperature stability of the microspheres. The formula of the present invention fully utilizes the mixed alkali effect of alkali metal oxides and the size difference between the alkali metal ions and alkaline earth metal ions, and through the introduction of elements and formula design, greatly improves the mechanical properties such as wear resistance, hardness, and thermal stability. By changing the microstructure of the glass, the ion migration in the glass is hindered, and the technical difficulties such as low wear resistance, low hardness, and fragility during drilling when commonly used hollow glass microspheres are used as lighteners in drilling fluids are solved.

[0044] (3) Physical or chemical methods are used to pre-treat the precursor particles after drying, thereby avoiding agglomeration between fine particles and significantly improving fluidity. Because the precursor particles have the characteristics of small particle size and large specific surface area, and they contain more alkali metals, alkaline earth metals and boron oxides, they are very easy to absorb moisture in the air and agglomerate. The present invention reduces the area and time of contact between water-absorbing groups such as hydroxyl groups and water molecules in the form of surface coating, or gives the surface the same charge to generate electric repulsion, so that the particles have excellent fluidity and dispersibility, avoiding adhesion between particles; and compared with untreated particles, the unit time processing capacity of the precursor particles in the high-temperature spheroidization process is greatly improved, saving the time cost of industrialization.

[0045] (4) The precursor particles are spheroidized at high temperature to prepare micron-sized hollow glass microspheres with uniform composition, dense structure, wear resistance and high hardness. The hollow glass microspheres are used as a lightening agent to prepare low-density drilling fluids, which have the advantages of safety and environmental protection, significant density reduction effect, adjustable density, good stability under high temperature and high pressure, lubrication and drag reduction, low wear of drill tools, improved mud cake quality, reduced filtration loss, good fluidity, no loss of MWD signal, and low cost.

[0046] (5) The surface treatment process of the lightening agent preferably uses one or more inorganic surface modifiers to further improve the wear resistance and impact resistance of the lightening agent; further, after the treatment with the inorganic surface modifier, one or more modifiers such as surfactants, unsaturated organic acids, dispersants, and water-soluble polymers are used for surface modification to improve the interfacial bonding strength between the lightening agent and the drilling fluid, further improve the wear resistance and impact resistance of the lightening agent, and reduce the migration of metal ions. DETAILED DESCRIPTION

[0047] To illustrate the present invention, the wear-resistant and high-strength lightener for drilling fluid and its preparation method are further described in detail below with reference to examples. However, the present invention is not limited to the examples.

[0048] Example 1

[0049] The specific implementation process is as follows:

[0050] (1) Preparation of precursor particles: the raw materials were weighed according to the formula 1 in Table 1 and pre-mixed, the pre-mixed materials were broken and ground by a ball mill, the particle size distribution D 90 of the broken and ground raw materials was 4.8 μm; the mixture was granulated by a dry granulator to obtain precursor particles with a particle size D 50 of 36 μm; the precursor particles were physically classified to obtain precursor particles with a particle size D 90 of 58 μm, and the remaining large-particle precursor particles were returned to the breaking and grinding section for repeated use.

[0051] (2) Pretreatment of precursor particles: the precursor particles prepared in step (1) were placed in a dryer and dried at a temperature of 80°C to obtain precursor particles with a water content of 0.32%; the same electric charge was given to the surface of the precursor particles by a corona charger to make the particles repel each other and achieve good fluidity.

[0052] (3) High-temperature hollow spheroidization of precursor particles: air was used as a combustion-supporting gas, the precursor particles prepared in step (2) were mixed with the air, and then the mixture was mixed with natural gas in a mixing chamber by pneumatic conveying; the mixed precursor particles, air and fuel were introduced into a high-temperature vitrification furnace with a temperature of 1150°C; the particles were melted into a glass melt under the action of surface tension, and a spherical shape was formed, and the high-temperature mixed gas was wrapped inside; after passing through the high-temperature forming zone, the glass melt was rapidly cooled to 400-600°C for 30-60 s, and then slowly cooled to room temperature for 1.0-1.5 h to form a wear-resistant high-strength lightweight agent with a density of 0.28 g / cm 3 , a particle size D50 of 36 μm, a particle size D90 of 58 μm and a strength of 20 MPa.

[0053] (4) Surface treatment of the lightweight agent: a commercially available vinyl silane coupling agent was selected, and the vinyl silane coupling agent with a mass of 0.3% of the lightweight agent was weighed as a surface modifier; the lightweight agent prepared in step (3) was modified by wet modification to coat a layer of vinyl silane coupling agent on the surface; after drying at 105°C by a drying device, a drilling fluid wear-resistant high-strength lightweight agent with a density of 0.28 g / cm 3 , a particle size D50 of 36 μm, a particle size D90 of 58 μm and a strength of 20 MPa was obtained. Example 2

[0054] The specific implementation process is as follows:

[0055] (1) Preparation of precursor particles: the raw materials were weighed according to the formula 2 in Table 1 and pre-mixed, the pre-mixed materials were broken and ground by a ball mill, the particle size distribution D 904.1 μm; the mixture was granulated by using a wet granulator to obtain precursor particles with a particle size D 50 32 μm; the precursor particles were prepared by physical classification to obtain precursor particles with a particle size D 90 54 μm, and the remaining large precursor particles were returned to the crushing and grinding section for reuse.

[0056] (2) Precursor particle pretreatment: the precursor particles prepared in step (1) were placed in a drying machine and dried at a temperature of 70°C to obtain precursor particles with a water content of 0.28%; the precursor particles were surface treated with an epoxy silane to obtain precursor particles with good fluidity.

[0057] (3) High-temperature hollow spheroidization of the precursor particles: 80% air and 20% oxygen were used as combustion-supporting gas, and the precursor particles prepared in step (2) were mixed with the combustion-supporting gas by using a pneumatic conveying method, and then the mixed material and fuel were mixed in a mixing chamber; the mixed precursor particles, air and fuel were introduced into a high-temperature vitrification furnace with a temperature of 1250°C; the particles were melted into a glass melt under the action of surface tension, and a spherical shape was formed, and the high-temperature mixed gas was wrapped in the interior; after passing through the high-temperature forming zone, the glass melt was rapidly cooled to a temperature of 400-600°C for 50-80 s, and then slowly cooled to room temperature for 1.5-2.0 h to obtain a wear-resistant high-strength lightweight agent with a density of 0.38 g / cm 3 , a particle size D50 of 32 μm, a particle size D90 of 54 μm and a strength of 40 MPa.

[0058] (4) Surface treatment of the lightweight agent: commercially available zirconium aluminate was selected as a surface modifier, and 0.3% zirconium aluminate was added to the lightweight agent, and the modified lightweight agent prepared in step (3) was dried at a temperature of 110°C by using a drying device to obtain a wear-resistant high-strength lightweight agent for drilling fluid with a density of 0.38 g / cm 3 , a particle size D50 of 32 μm, a particle size D90 of 54 μm and a strength of 40 MPa. Example 3

[0059] The specific implementation process is as follows:

[0060] (1) Preparation of precursor particles: the raw materials were weighed according to the formula 3 in Table 1 and pre-mixed, and the pre-mixed material was crushed and ground by using a ball mill; the particle size distribution D 90 of the crushed and ground raw material was 3.5 μm; the mixture was granulated by using a dry granulation method to obtain precursor particles with a particle size D 50 of 25 μm; the precursor particles were prepared by physical classification to obtain precursor particles with a particle size D 90 of 50 μm, and the remaining large precursor particles were returned to the crushing and grinding section for reuse.

[0061] (2) Precursor particle pretreatment: the precursor particles prepared in step (1) are placed in a drying machine and dried at a temperature of 90°C to obtain precursor particles with a water content of 0.20%; the precursor particles are surface treated with triisopropyl aluminate to obtain precursor particles with good fluidity.

[0062] (3) High-temperature hollow spheroidization of precursor particles: 60% air and 40% oxygen are used as combustion-supporting gas, and the precursor particles prepared in step (2) are mixed with the combustion-supporting gas; the mixed material and petroleum gas are mixed in a mixing chamber by means of pneumatic conveying; the mixed precursor particles, air and fuel are introduced into a high-temperature vitrification furnace with a temperature of 1350°C; the particles melt into glass melt under the action of surface tension, and form spherical shape with the high-temperature mixed gas wrapped inside; after passing through the high-temperature forming zone, the glass melt is rapidly cooled to 400-600°C for 20-40 seconds, and then slowly cooled to room temperature for 0.5-1.0 hours to form a wear-resistant high-strength lightweight agent with a density of 0.47 g / cm 3 , a particle size D50 of 25 μm, a particle size D90 of 50 μm, and a strength of 60 MPa.

[0063] (4) Surface treatment of the lightweight agent: commercially available triisopropyl aluminate is selected as a surface modifier, and 0.5% triisopropyl aluminate by mass of the lightweight agent is weighed and used to modify the lightweight agent prepared in step (3) by wet method; the modified lightweight agent is dried at 135°C by using a drying device; then the lightweight agent is surface treated with 0.2% poly-methylacrylic acid by mass of the lightweight agent, and dried at 110°C; finally, a wear-resistant high-strength lightweight agent for drilling fluid with a density of 0.47 g / cm 3 , a particle size D50 of 28 μm, a particle size D90 of 50 μm, and a strength of 60 MPa is obtained. Example 4

[0064] The specific implementation process is as follows:

[0065] (1) Preparation of precursor particles: the raw materials are weighed according to the formula 4 in Table 1 and pre-mixed; the pre-mixed material is broken and ground by using a ball mill, and the particle size distribution D 90 of the broken and ground raw material is 2.5 μm; the mixed material is granulated by using dry granulation to obtain precursor particles with a particle size D 50 of 25 μm; the precursor particles with a particle size D 90 of 45 μm are obtained by physical classification treatment, and the remaining large precursor particles are returned to the breaking and grinding section for repeated use.

[0066] (2) Precursor particle pretreatment: the precursor particles prepared in step (1) are placed in a drying machine and dried at a temperature of 110°C to obtain precursor particles with a water content of 0.18%; the precursor particles are surface treated with polycaprolactone diol to obtain precursor particles with good fluidity.

[0067] (3) High-temperature hollow spheroidization of precursor particles: 40% air and 60% oxygen are used as combustion-supporting gas, and the precursor particles prepared in step (2) are mixed with the combustion-supporting gas; the mixed material and petroleum gas are mixed in a mixing chamber by means of pneumatic conveying; the mixed precursor particles, air and fuel are introduced into a high-temperature sintering furnace with a temperature of 1450°C; the particles melt into a glass melt under the action of surface tension, and form a spherical shape with the high-temperature mixed gas wrapped inside; after passing through the high-temperature forming zone, the glass melt is rapidly cooled to 400-600°C for 20-40s, and then slowly cooled to room temperature for 1.0-2.0h to form a wear-resistant high-strength lightweight agent with a density of 0.55g / cm 3 , a particle size D50 of 25μm, a particle size D90 of 45μm and a strength of 103MPa.

[0068] (4) Surface treatment of the lightweight agent: commercially available monoalkoxy titanate is selected as a surface modifier, and 0.8% of the mass of the lightweight agent is aluminum monoalkoxy titanate; the lightweight agent prepared in step (3) is modified by wet method, and dried at 140°C by using a drying device; then the lightweight agent is surface treated with 0.3% of the mass of the lightweight agent of sodium dodecyl benzene sulfonate, and dried at 100°C, finally a wear-resistant high-strength lightweight agent for drilling fluid with a density of 0.55g / cm 3 , a particle size D50 of 25μm, a particle size D90 of 45μm and a strength of 103MPa is obtained. Example 5

[0069] The specific implementation process is as follows:

[0070] (1) Preparation of precursor particles: the raw materials are weighed according to the formula 5 in Table 1 and pre-mixed, the pre-mixed material is broken and ground by using a ball mill, and the particle size distribution D 90 of the broken and ground raw material is 1.8μm; the mixed material is granulated by using a wet granulation method to obtain precursor particles with a particle size D 50 of 16μm; the precursor particles are physically classified to obtain precursor particles with a particle size D 90 of 35μm, and the remaining large particle precursor particles are returned to the breaking and grinding section for repeated use.

[0071] (2) Precursor particle pretreatment: the precursor particles prepared in step (1) are placed in a drying machine and dried at a temperature of 110 DEG C to obtain precursor particles with a water content of 0.18%; the precursor particles are surface treated with sodium lauryl polyoxyethylene ether sulfate to obtain precursor particles with good fluidity.

[0072] (3) High-temperature hollow spheroidization of precursor particles: the precursor particles prepared in step (2) are mixed with oxygen as a combustion-supporting gas, and then the mixed material is mixed with natural gas in a mixing chamber by pneumatic conveying; the mixed precursor particles, air and fuel are introduced into a high-temperature vitrification furnace with a temperature of 1450 DEG C; the particles are melted into a glass melt under the action of surface tension to form a spherical shape, and the high-temperature mixed gas is wrapped inside; after passing through the high-temperature forming zone, the glass melt is rapidly cooled to 400-600 DEG C for 20-40 s, and then slowly cooled to room temperature for 1.0-2.0 h to form a wear-resistant high-strength lightweight agent with a density of 0.60 g / cm 3 , a particle size D50 of 16 μm, a particle size D90 of 35 μm, and a strength of 150 MPa.

[0073] (4) Surface treatment of the lightweight agent: commercially available 80% monoalkoxy titanate and 30% aluminate coupling agent are selected as a composite surface modifier, and 0.5% of the composite surface modifier by mass of the lightweight agent is weighed and used to dry-modify the lightweight agent prepared in step (3); the modified lightweight agent is dried at 140 DEG C using a drying device; then a mixed treatment agent (60% dodecylbenzenesulfonic acid sodium and 40% lauryl polyoxyethylene ether sulfate) with a mass fraction of 0.4% of dodecylbenzenesulfonic acid sodium and lauryl polyoxyethylene ether sulfate is used to treat the surface of the lightweight agent, and the treated lightweight agent is dried at 100 DEG C; finally, a wear-resistant high-strength lightweight agent for drilling fluid with a density of 0.60 g / cm 3 , a particle size D50 of 16 μm, a particle size D90 of 35 μm, and a strength of 150 MPa is obtained.

[0074] Table 1: Mass fraction of each component in examples 1-5

[0075]

[0076] The upper and lower limits and interval values of each raw material and process parameter involved in the present application can all achieve the present application, and are not listed one by one here.

Claims

1. A wear-resistant and high-strength reducing agent for drilling fluid, characterized in that It is made from the following components. When the sum of the raw material components is calculated as 100%, the mass content of each component is: Silicon dioxide: 65~75% Aluminum oxide: 5~10% Boron trioxide: 5~10% Alkaline earth metal oxides: 5~10% Alkali metal oxides: 5~10% Rare earth elements: 0.2~3% Ferric oxide: 0~2% Manganese dioxide: 0~2% Zirconia: 0~2% Zinc oxide: 0~2% Other trace element materials: 0.2~5%; The content of each compound in the alkaline earth metal oxide is calculated as 100%. The content of the above-mentioned raw materials is as follows: calcium oxide 70-80%, magnesium oxide 10-25%, strontium oxide 0-15%; the content of the above-mentioned alkali metal oxides when the total content of each compound is calculated as 100% is as follows: sodium oxide 70-80%, potassium oxide 10-25%, lithium oxide 0-10%; the content of the above-mentioned rare earth elements when the total content of each compound is calculated as 100% is as follows: cerium oxide and lanthanum oxide total content is 75-90%, yttrium oxide 0-10%, neodymium oxide 0-10%, scandium oxide 0-10%; The preparation method of the wear-resistant and high-strength lightener for drilling fluid is implemented by the following steps: (1) Preparation of precursor particles Accurately weigh each raw material component according to the formula composition, premix all the components, crush and grind them to a certain particle size, and then granulate them to prepare precursor particles with a particle size D50 of 20-40μm; after physical classification, control the particle size D90 of the precursor particles to ≤60μm; (2) Precursor particle pretreatment The precursor particles prepared in step (1) are dried to reduce their moisture content to less than 0.5%; then, the precursor particles are pretreated by physical or chemical methods to reduce agglomeration between fine particles and improve their fluidity; (3) High-temperature hollow spheroidization of precursor particles After the precursor particles prepared in step (2) are fully mixed with the combustion-supporting gas, the materials and the combustion-supporting gas are transported into a mixing chamber by pneumatic conveying to be mixed with the fuel. The mixed precursor particles, combustion-supporting gas and fuel are introduced into a high-temperature vitrification furnace with a temperature of 1000-1450°C. The particles are melted into a glass melt at high temperature and formed into a spherical shape under the action of surface tension. At the same time, the high-temperature mixed gas is wrapped inside the glass melt. After the glass melt passes through the high-temperature forming zone, it is rapidly cooled to 400-600°C within 2 minutes, and then slowly cooled to room temperature over 1-4 hours to form a density of 0.28-0.60 g / cm 3 , wear-resistant and high-strength lightener with a particle size D50 of 20~40μm, a particle size D90≤60μm, and a strength of 20~150MPa; (4) Surface treatment of lightening agent: Select a surface treatment agent and perform surface treatment on the lightening agent prepared in step (3) to obtain a density of 0.28~0.60g / cm 3 , a wear-resistant and high-strength lightener for drilling fluid with a particle size D50 of 20~40μm, a particle size D90≤60μm, and a strength of 20~150MPa; the surface treatment agent is any one of a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, a zirconium aluminate coupling agent, a surfactant, an organosilicon, an unsaturated organic acid and an organic oligomer, a hyperdispersant, a water-soluble polymer, and an inorganic surface modifier, or a mixture of two or more thereof; the surface treatment method is: first using an inorganic surface modifier for surface treatment, and then using a surfactant, an unsaturated organic acid, a dispersant, and a water-soluble polymer for surface modification.

2. The wear-resistant and high-strength lightening agent for drilling fluid according to claim 1, characterized in that: The other trace element materials are one or a mixture of two or more of tungsten oxide, vanadium oxide and phosphorus pentoxide.

3. The method for preparing a wear-resistant and high-strength lightening agent for drilling fluid according to claim 1 or 2, characterized in that: The physical method is to use a corona generator or a paradigm generator device to give the particles the same charge on the surface, achieving a mutual repulsion effect, thereby achieving good fluidity; the chemical method is to use a surface treatment agent to modify the surface of the dried precursor particles to avoid particle agglomeration and improve their fluidity.

4. The method for preparing a wear-resistant and high-strength lightening agent for drilling fluid according to claim 3, wherein: The surface treatment agent is any one 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, inorganic surface modifier or a mixture of two or more thereof.

5. The method for preparing a wear-resistant and high-strength lightening agent for drilling fluid according to claim 4, characterized in that: In step (3), the combustion-supporting gas is air, oxygen or a combination of the two, and the fuel is one or more combinations of coal gas, natural gas or petroleum gas.

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