Long-acting sand-prevention and sand-fixing composite material for fine sandstone oil reservoir and preparation method thereof

Abstract

The application discloses a kind of powder fine sandstone reservoir long-acting sand prevention and sand fixation composite material and its preparation method in the technical field of oil field chemistry, its core is in using two kinds of functional inorganic nanometer materials synergistic organic polymer, constructs multistage consolidation system.The composite material is composed of two components of main agent and curing agent.Main agent preparation includes: with brine as medium, clay stabilizer, polycarboxylate dispersant and other additives are sequentially added, and as key component, organic silane modified yttrium doped nanometer bokhite and titanate coupling agent modified zirconium aluminum layered double hydroxide, after dispersion, with water-based epoxy resin emulsion, water-based polyurethane emulsion and the like are compounded, finally, the pH value is adjusted to obtain.The curing agent is polyether amine aqueous solution.Two components are mixed and injected into formation in proportion during construction.The material can realize efficient wrapping and strong and tough cementation to fine sand, form artificial well wall with high consolidation strength, good permeability retention and excellent weather resistance, and achieve the purpose of long-acting sand prevention and sand fixation.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to a long-lasting sand-fixing and sand-stabilizing composite material for fine sandstone reservoirs and its preparation method. Background Technology

[0002] Loose sandstone reservoirs, especially fine-grained sandstone reservoirs, generally face severe sand production problems during oil and gas extraction. The migration of fine sand particles in the formation under fluid erosion and pressure changes not only leads to a sharp decline in well production and accelerated equipment wear, but can also trigger serious engineering accidents such as formation collapse and wellbore blockage, directly hindering the efficient and safe development of oilfields. These reservoirs are characterized by loose lithology, high clay content, fine sand grain size, large specific surface area, and high surface electronegativity, posing significant challenges to traditional sand control technologies. How to achieve long-term, stable consolidation of fine sand particles while maximizing the protection of the formation's original permeability has become one of the key technical challenges urgently needing to be overcome in oilfield development.

[0003] Currently, sand control technologies applied in the field are mainly divided into two categories: mechanical sand control and chemical sand control. Mechanical sand control technologies, such as screen pipes and gravel packing, focus on physical interception. Although they have a long effective period, they mainly act near the wellbore and cannot achieve deep formation consolidation. Furthermore, they are prone to blockage by fine sand, leading to a reduction in seepage area and affecting production capacity. Chemical sand control technologies mainly include resin sand fixation and inorganic precipitation sand fixation. Their advantage lies in their ability to penetrate deep into the formation and cement sand particles. However, existing chemical systems have significant limitations: the solidified bodies formed by conventional resin sand fixation agents are often brittle and prone to microcracks and failure under long-term formation stress. Moreover, their resistance to high temperatures and high salinity is insufficient, and they are prone to aging and degradation in harsh reservoir environments. Inorganic precipitation sand fixation agents generally suffer from low consolidation strength, difficulty in controlling reaction rates, and easy damage to formation porosity. The more fundamental contradiction lies in the fact that most chemical sand-stabilizing agents struggle to balance high-strength consolidation with high permeability retention. Increasing consolidation strength often comes at the cost of sacrificing formation seepage capacity, while pursuing low damage frequently results in loose consolidation, failing to effectively curb the migration of fine silt. Furthermore, existing technologies generally have poor adaptability to formations with high clay content, and the hydration and swelling of clay minerals further exacerbates permeability damage.

[0004] To systematically address the aforementioned contradictions, the industry has shifted its research focus to constructing novel sand control systems through material innovation. In recent years, nanomaterials and organic-inorganic hybrid technologies have shown great potential. By introducing functional nanocomponents to modify traditional resins or constructing multi-stage reaction composite systems, it is hoped that the bonding force between sand particles and the toughness of the solidified body can be enhanced at the microscopic level. Based on this, this invention aims to overcome the performance limitations of single materials by synthesizing two inorganic modified core materials with special interfacial and reactive activities through molecular design, and then enabling them to produce a synergistic effect with high-performance organic polymer materials. The goal is to develop a novel composite material and its preparation method. This system can first efficiently adsorb and encapsulate fine sand particles, followed by a controllable, progressive solidification reaction at formation temperatures, ultimately forming a solidified sand body with high mechanical strength, good permeability, excellent temperature and salt resistance, and long-term durability. This provides a revolutionary long-term sand control and solidification solution for fine sandstone reservoirs. Summary of the Invention

[0005] The purpose of this invention is to provide a long-lasting sand control and sand fixation composite material for fine sandstone reservoirs and its preparation method, which overcomes the technical problems of existing sand control technologies, such as difficulty in balancing consolidation strength and formation permeability, poor consolidation effect on fine sand, insufficient stability in high-temperature and high-salinity reservoir environments, and short effective period.

[0006] The present invention achieves the above objectives through the following technical solutions: A method for preparing a long-lasting sand-fixing and sand-stabilizing composite material for fine sandstone reservoirs, comprising the following steps: S1. By weight, add brine to a mixing vessel, add 1-5 parts of clay stabilizer, stir, then add 1-3 parts of polycarboxylate dispersant and 0.1-10 parts of corrosion and scale inhibitor, stir, add 10-25 parts of organosilane-modified yttrium-doped nano-boehmite, 5-15 parts of titanate coupling agent-modified zirconium aluminum layered double hydroxide, and 0.5-2 parts of curing accelerator, stir, and sonicate to obtain a suspension; add 20-40 parts of waterborne epoxy resin emulsion and 2-8 parts of waterborne polyurethane emulsion dropwise to the suspension, continue stirring to obtain a composite emulsion; S2. Under stirring, adjust the pH value of the composite emulsion to 7.5-8.5 to obtain the main component; dissolve the polyetheramine curing agent in water and stir to obtain the curing agent component; the long-term sand control and sand fixation composite material for fine sandstone reservoirs is composed of the main component and the curing agent component.

[0007] In this invention, the construction of a long-term sand-fixing and sand-stabilizing composite material for fine sandstone reservoirs is based on a multi-scale collaborative design concept. The main agent is formulated using formation brine as the continuous phase. First, a clay stabilizer is dissolved to inhibit the hydration and swelling of reservoir clay. Then, a dispersant and corrosion / scale inhibitor are added to ensure system stability and equipment safety. Subsequently, a nano-reinforced material with dual surface modification and a latent curing accelerator are introduced. Through vigorous stirring and ultrasonic cavitation, stable suspension and uniform distribution of nanoparticles in the aqueous phase are achieved. Waterborne epoxy resin emulsion and waterborne polyurethane emulsion are slowly added dropwise, forming a structurally uniform composite emulsion with good interfacial compatibility among the components through emulsification within the system. The system is adjusted to a weakly alkaline state to optimize storage stability, yielding the main agent; the curing agent is a water-soluble polyetheramine solution. After on-site mixing, the active amino and epoxy groups of the polyetheramine rapidly undergo nucleophilic ring-opening polymerization, forming a highly cross-linked three-dimensional network. The polyurethane component simultaneously participates in the reaction, introducing flexible segments to enhance the system's toughness and impact resistance. Organically modified nano-boehmite and layered double hydroxides are uniformly embedded in the polymer network. The modified layer forms strong chemical bonds and physical entanglements with the resin matrix, effectively transferring loads, hindering microcrack propagation, and significantly improving the composite material's resistance to salt water, resistance to temperature changes, and long-term structural stability. Ultimately, a dense, high-strength, and high-toughness cementing layer is constructed in situ on the surface of loose sand grains. This structure combines excellent mechanical properties, permeability retention, and environmental adaptability, achieving effective control and long-term consolidation of sand production in fine sandstone reservoirs, meeting the engineering requirements for long-term oilfield production.

[0008] According to a preferred embodiment of the present invention, in step S1, the ultrasonic treatment time is 30-60 min.

[0009] According to a preferred embodiment of the present invention, in step S2, the mass ratio of the main agent component to the curing agent component is (8-12):1.

[0010] According to a preferred embodiment of the present invention, the method for preparing the organosilane-modified yttrium-doped nanoboehmite includes: A1. By weight, add deionized water to a three-necked flask and heat to 84-86℃. While stirring, add dropwise a mixed salt solution formed by dissolving 80-120 parts of aluminum nitrate nonahydrate and 5-15 parts of yttrium nitrate hexahydrate in deionized water, along with sodium hydroxide solution, to the three-necked flask to adjust the pH to 8.5-9.0. After the addition is complete, age and crystallize at 94-96℃ to obtain a slurry. Centrifuge the slurry to obtain a solid product. Wash the solid product alternately with deionized water and ethanol to obtain a wet gel. A2. The wet gel was dried in a vacuum drying oven at 58-62℃ to obtain dry yttrium-doped boehmite powder. The dried yttrium-doped boehmite powder was redispersed in anhydrous toluene and sonicated to obtain a suspension. The suspension was transferred to a reaction flask equipped with a reflux condenser. Dry nitrogen gas was continuously bubbled through the bottom of the reaction flask. Silane coupling agent KH560 was added, and dry nitrogen gas was introduced. The mixture was heated to 108-112℃ and stirred under reflux. The methanol generated in the reaction was discharged through the upper end of the condenser with the nitrogen gas flow to obtain the reaction mixture. The reaction mixture was centrifuged, washed with anhydrous toluene, and finally dried in a vacuum drying oven at 58-62℃ and ground.

[0011] In this invention, the preparation mechanism of organosilane-modified yttrium-doped nanoboehmite begins with an aqueous co-precipitation process. Under controlled thermal conditions and continuous stirring, aqueous solutions of aluminum and yttrium sources are simultaneously added dropwise with an alkaline precipitant. The system maintains a weakly alkaline state, promoting the directional hydrolysis of metal ions to generate an amorphous hydroxide colloidal precursor. After moderate heat treatment and aging, the precursor undergoes dehydration condensation and lattice reconstruction, gradually transforming into a fully crystalline boehmite phase. Trivalent yttrium ions are selectively incorporated into the lattice, effectively controlling crystal growth habits, inhibiting grain aggregation, and significantly improving surface hydroxyl density and thermal stability. After centrifugation and washing to thoroughly remove impurity ions, the powder is dried under low-temperature vacuum to obtain a loose, porous dry gel. In the surface modification stage, the dry gel is highly dispersed in an anhydrous organic solvent, a silane coupling agent is added, and the mixture is heated under reflux under inert gas protection. The hydrolyzable alkoxy groups in the silane molecules undergo a condensation reaction with the hydroxyl groups on the boehmite surface, removing small molecule alcohol byproducts and forming stable silicon-oxygen metal chemical bonds. The key lies in the continuous introduction of inert gas into the reaction system. As the gas flows through the condenser and reflux device, volatile alcohol byproducts are selectively carried out of the reaction zone, effectively disrupting the chemical equilibrium and driving the grafting reaction towards completion. After separation and purification, modified nanoparticles with a uniformly coated organosilane monolayer are obtained. This modification significantly reduces the surface polarity of the material, enhances its wettability, dispersion stability, and interfacial compatibility with the resin matrix in organic media, and provides a molecular-level bonding basis for the composite system.

[0012] According to a preferred embodiment of the present invention, in step A1, the aging and crystallization time at 94-96°C is 12-14 hours.

[0013] According to a preferred embodiment of the present invention, in step A2, the time for heating to 108-112°C and refluxing with stirring is 6-12 hours.

[0014] According to a preferred embodiment of the present invention, the method for preparing the titanate coupling agent modified zirconium aluminum layered double hydroxide includes: B1. By weight, dissolve 30-34 parts of zirconium nitrate hexahydrate and 150-170 parts of aluminum nitrate nonahydrate in an aqueous nitric acid solution to obtain solution A; dissolve sodium hydroxide and sodium carbonate in deionized water to obtain solution B; add solutions A and B dropwise to a reactor containing deionized water under stirring, adjust the pH to 9.0-10.0, and obtain a reaction solution; transfer the reaction solution to a high-pressure reactor and perform hydrothermal crystallization at 98-102℃; after natural cooling, collect the precipitate by centrifugation, wash the precipitate with deionized water, and obtain a wet filter cake; B2. Dry the wet filter cake in a vacuum drying oven at 78-82℃ to obtain a dry powder; redisperse the dry powder in xylene and sonicate to obtain a suspension; transfer the suspension to a reaction flask, add titanate coupling agent KR-138S, purge with nitrogen, and heat to 135-145℃ under reflux with stirring; after the reaction is complete, filter to obtain a solid product, wash the solid product with isopropanol, and finally dry it in a vacuum drying oven at 58-62℃.

[0015] In this invention, the preparation mechanism of zirconium aluminum hydroxide modified with titanate coupling agent focuses on the precise construction of layered crystals and surface hydrophobic modification. Initially, to overcome the problem of zirconium ions readily hydrolyzing in aqueous solution to form polynuclear hydroxyl clusters, the zirconium source and aluminum source are co-dissolved in a dilute acidic aqueous solution. The acidic environment effectively stabilizes the valence state of zirconium ions, ensuring that the metal ions participate in the reaction in a homogeneous monomeric state. Under high-speed shearing and precise online pH control, the acidic metal salt solution and an alkaline precipitant containing hydroxide and carbonate ions are added dropwise simultaneously, with the system strictly maintained within a weakly alkaline window. This promotes the co-precipitation of a layered precursor composed of zirconium aluminum hydroxide octahedra with carbonate anions embedded in the interlayer. After hydrothermal crystallization, the precursor completes crystal growth and ordered layered structure formation in a high-temperature hydrothermal environment, yielding a layered double hydroxide with high crystallinity and uniform interlayer spacing. After washing and drying, a white powder is obtained. During surface modification, the powder is dispersed in a high-boiling-point organic solvent, and a titanate coupling agent is added. The mixture is then heated under an inert atmosphere and refluxed. The alkoxy groups in the titanate molecules undergo transesterification with the hydroxyl groups on the material surface, forming titanium-oxygen bonds and releasing alcohol byproducts. Through the synergistic effect of continuous bubbling with inert gas and reflux condensation, the byproducts are efficiently removed from the reaction system, significantly reducing their partial pressure and promoting the complete forward reaction. Post-treatment involves separation and washing to obtain a layered material with organically functionalized surfaces. This modification significantly reduces the surface energy of the material, changing it from hydrophilic to hydrophobic, greatly improving its dispersion uniformity in the polymer matrix. The long chains of the titanate form physical entanglements and interfacial chemical interactions with the resin, providing excellent stress transfer and reinforcement effects for the composite material.

[0016] According to a preferred embodiment of the present invention, in step B1, the hydrothermal crystallization time at 98-102°C is 12-14 hours.

[0017] According to a preferred embodiment of the present invention, in step B2, the time for reflux stirring at 135-145°C is 8-10 hours.

[0018] The present invention also provides a long-term sand control and sand stabilization composite material for fine sandstone reservoirs prepared according to the preparation method of the aforementioned long-term sand control and sand stabilization composite material for fine sandstone reservoirs.

[0019] The beneficial effects of this invention are as follows: The long-lasting sand-fixing composite material for fine sandstone reservoirs provided by this invention innovatively combines two functionally complementary inorganic modified core materials with organic polymers, exhibiting outstanding comprehensive technical effects. It fundamentally solves a series of problems in existing technologies, such as the prominent contradiction between consolidation strength and permeability, poor consolidation effect on fine sand, weak resistance to high-temperature and high-salt environments, and short effective period. Firstly, this material demonstrates exceptional performance in terms of sand-fixing properties and mechanical strength. Its core component, organosilane-modified yttrium-doped nano-boehmite, with its nanosheet structure and high surface activity, can deeply encapsulate and firmly adsorb onto the surface of fine sand particles. The strong charge neutralization effect of rare earth yttrium ions reduces the repulsive force between sand particles, achieving efficient "primary consolidation." Subsequently, the titanate coupling agent-modified zirconium aluminum layered double hydroxide and water-based epoxy resin work synergistically, through chemical cross-linking and physical filling, to construct a strong and tough three-dimensional organic-inorganic hybrid network structure, endowing the consolidated body with extremely high mechanical strength. Indoor core simulation experiments show that after treatment with this material, the uniaxial compressive strength of the core solidification body significantly exceeds that of conventional chemical sand-fixing agents. It can withstand high formation stress without damage, and can achieve near-complete consolidation even for extremely fine silt with very low sand production, effectively ensuring the long-term stability of the wellbore and the continuity of production.

[0020] Secondly, the material of this invention has achieved a breakthrough in protecting reservoir permeability, successfully achieving a balance between high-strength consolidation and high permeability retention. This effect is mainly due to the ingenious design of the system: the layered structure of the titanate-modified layered double hydroxide itself provides physical support and spacing between sand grains, and its hydrophobic organic long chains prevent excessive densification of the consolidated body; at the same time, the introduction of waterborne polyurethane flexible segments increases the toughness and elasticity of the consolidated body, reducing pore blockage caused by excessive rigidity. More importantly, the entire solidification reaction is carried out in stages and is controllable, avoiding pore throat blockage caused by instantaneous violent reactions. Therefore, while achieving high-strength consolidation, the treated core can maintain a high level of gas or liquid phase permeability retention, which means that the seepage channels of crude oil or natural gas are protected to the greatest extent, thereby effectively controlling sand while maximizing the production capacity of the oil well, and solving the long-standing contradiction between "sand control" and "production preservation" in traditional sand control technology.

[0021] Finally, the materials of this invention exhibit significant advantages in long-term stability, environmental adaptability, and construction feasibility. Both inorganic modified core materials are specially designed to possess excellent thermal stability and chemical inertness. The zirconium aluminum layered double hydroxide itself has a stable structure, and the titanate groups introduced after modification can undergo slow cross-linking at high temperatures, providing long-term strength support. This results in a very low strength decay rate after long-term aging in the harsh high-temperature and high-salt reservoir environment, significantly extending the effective lifespan. The entire system adopts a two-component design of main agent and curing agent, which is stable at room temperature and can be pumped in during construction through simple mixing, with a wide operating window and simple process. The latent curing accelerator ensures that the material can fully penetrate to the depths in the formation at room temperature, and is only activated and cured when the target temperature range is reached, achieving "deep placement" and "precise curing," which is particularly suitable for highly heterogeneous fine sandstone reservoirs. In summary, this composite material combines high strength, high permeability, long-term stability, and convenient construction, providing a highly competitive and innovative solution for the efficient, safe, and long-term development of fine sandstone reservoirs. Detailed Implementation

[0022] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0023] Example 1 Preparation of organosilane-modified yttrium-doped nanoboehmite Step A1: Add 500.0 g of deionized water to a 2000 mL three-necked flask equipped with a mechanical stirrer, condenser, and thermometer. Turn on the stirrer and heat until the water temperature reaches and stabilizes at 85.0 °C. Prepare the mixed salt solution: Dissolve 100.0 g of aluminum nitrate nonahydrate and 10.0 g of yttrium nitrate hexahydrate in 100.0 g of deionized water and stir until completely transparent. Prepare a 2.5 mol / L sodium hydroxide solution for later use. Under continuous vigorous stirring, simultaneously add the above mixed salt solution and sodium hydroxide solution dropwise to the three-necked flask using two constant flow pumps. By controlling the dropping rate of both, the pH value of the reaction system is maintained within the range of 8.8 ± 0.1. The entire parallel-flow dropping process lasts for 120 min. After the dropping is completed, maintain the temperature at 85.0 °C, continue stirring, and age and crystallize for 12.0 h. The resulting slurry was then transferred to a centrifuge and centrifuged at 8000 rpm for 10 min, discarding the supernatant. The collected solid precipitate was washed three times each with deionized water and anhydrous ethanol, centrifuged after each wash, until the washing solution was neutral as determined by pH paper, finally yielding yttrium-doped boehmite wet gel.

[0024] Step A2: Transfer the above wet gel to a vacuum drying oven and dry it at 60.0℃ and -0.09MPa for 12.0h to obtain dry yttrium-doped boehmite powder. Accurately weigh 80.0g of this dried powder and place it in a 500mL beaker, then add 300.0g of anhydrous toluene. Place the beaker in an ultrasonic cleaner and sonicate it at 40kHz and 300W for 30min to obtain a uniformly dispersed suspension. Transfer this suspension to another 1000mL three-necked flask equipped with a reflux condenser, a nitrogen inlet tube (inserted below the liquid surface), and a thermometer. Turn on the magnetic stirrer and heat, while continuously introducing dry nitrogen gas through the nitrogen inlet tube at a flow rate of 30mL / min for bubbling. When the system temperature reaches 60.0℃, slowly add 6.4g of silane coupling agent KH560 through a constant-pressure dropping funnel. The mixture was heated to 110.0℃ and refluxed with stirring for 8.0 h. The methanol byproduct generated during the reaction was carried by a nitrogen stream and discharged through the top of the condenser. After the reaction was complete, heating and nitrogen were stopped. The reaction solution was allowed to cool to room temperature and then transferred to a centrifuge tube, centrifuged at 8000 r / min for 10 min. The solid product was collected and washed three times with fresh anhydrous toluene, centrifuged after each wash. Finally, the washed solid was placed in a vacuum drying oven and dried at 60.0℃ for 12.0 h. After drying, it was ground and passed through a 200-mesh sieve to obtain organosilicon-modified yttrium-doped boehmite nanoparticles, denoted as compound A.

[0025] Preparation of zirconium aluminum layered double hydroxide modified with titanate coupling agent Step B1: Preparation of Solution A: Dissolve 32.0g of zirconium nitrate hexahydrate and 160.0g of aluminum nitrate nonahydrate in 200.0g of 0.1mol / L nitric acid aqueous solution, stirring until completely dissolved to obtain a clear solution. Preparation of Solution B: Dissolve 38.4g of sodium hydroxide and 9.6g of sodium carbonate in 200.0g of deionized water, stirring until completely dissolved to obtain a clear solution. In a 2000mL beaker, pre-add 100.0g of deionized water and place it under a high-speed shear dispersion emulsifier. Turn on the emulsifier and set the speed to 10000r / min. Under vigorous shear stirring, use two constant flow pumps to slowly and evenly add solutions A and B dropwise to the deionized water in the beaker simultaneously, controlling the total dropping time to 60min. During the dropping process, use a pH meter to monitor the pH value of the system in real time, and adjust the dropping rate of the two solutions to stabilize the pH at 9.5±0.1. After the addition was complete, the mixture was stirred at high speed for 30 minutes to obtain a slurry precursor. This precursor slurry was transferred to a 500 mL PTFE-lined high-pressure reactor, sealed, and placed in an oven for hydrothermal crystallization at 100.0 °C for 12.0 h. After the process was complete, the mixture was allowed to cool naturally to room temperature. The reactor was then opened, and the contents were transferred to a centrifuge cup. The precipitate was collected by centrifugation at 8000 rpm for 10 minutes. The precipitate was repeatedly washed with deionized water and centrifuged until the conductivity of the washing solution was below 50 μS / cm, yielding a wet filter cake of carbonate-type zirconium aluminum layered double hydroxide.

[0026] Step B2: Place the above wet filter cake in a vacuum drying oven and dry it at 80.0℃ and -0.09MPa for 12.0h to obtain dried ZrAl-LDH powder. Accurately weigh 100.0g of this dried powder and disperse it in 400.0g of xylene. Sonicate the mixture (40kHz, 300W) for 30min to form a uniform suspension. Transfer this suspension to a 1000mL three-necked flask equipped with a reflux condenser and a nitrogen inlet tube. Start stirring and heating while simultaneously purging with nitrogen. When the temperature reaches 80.0℃, add 15.0g of titanate coupling agent KR-138S. Continue heating to 140.0℃ and reflux the reaction mixture at this temperature for 8.0h. After the reaction is complete, stop heating and hot filter the reaction mixture through a Buchner funnel while it is still hot. The filter cake was collected and washed twice with petroleum ether (boiling range 60-90℃), followed by three washes with isopropanol to thoroughly remove residual solvent and unreacted coupling agent. Finally, the solid product was dried in a vacuum drying oven at 60.0℃ for 24.0 h to obtain titanate coupling agent modified zirconium aluminum layered double hydroxide, denoted as compound B.

[0027] Preparation of long-term sand control and sand stabilization composite materials for fine sandstone reservoirs Preparation of the main component: Add 800.0 g of simulated formation brine (mineralization 30000 mg / L, calcium and magnesium ion concentration 2000 mg / L) to a 5 L main mixing vessel equipped with a stirrer and heating jacket. Start the stirrer and set the speed to 500 r / min. Add 30.0 g of quaternary ammonium salt clay stabilizer (purchased from Kaifeng Hengju Biotechnology Co., Ltd. HJZ-500-1), 20.0 g of polycarboxylate dispersant (purchased from Zhejiang Xinqi Chemical Co., Ltd.), and 5.0 g of hydroxyethylidene diphosphonic acid corrosion and scale inhibitor (purchased from Jinan Hongwang Chemical Co., Ltd.) sequentially to the vessel, and continue stirring for 15.0 min to ensure complete dissolution of all additives. While maintaining stirring, add 150.0 g of the previously prepared compound A, 100.0 g of the previously prepared compound B, and 10.0 g of curing accelerator (purchased from Greenlink (Jining) Chemical Technology Co., Ltd. TY-24 latent type) sequentially to the vessel. After all solids have been added, the stirring speed is increased to 1000 r / min and maintained at this speed for 60.0 min. During this period, the material in the vessel is subjected to auxiliary ultrasonic treatment for 30.0 min using a probe-type ultrasonic cell disruptor (600W power, 2s operation, 3s interval) to obtain a homogeneous and stable grayish-white suspension. The stirring speed is then adjusted back to 300 r / min. 300.0 g of waterborne epoxy resin emulsion (purchased from Zhejiang Anbang New Material Development Co., Ltd., solid content 50%) and 50.0 g of waterborne polyurethane emulsion (purchased from Weifang Jinglong Waterproof Materials Co., Ltd., solid content 40%) are slowly added dropwise to the suspension through a constant pressure dropping funnel, controlling the dropping rate to ensure a total dropping time of no less than 30 min. After the dropping is complete, stirring continues at 300 r / min for 60.0 min to form a homogeneous milky-white composite emulsion. Under low-speed stirring (200 r / min), a 1.0 mol / L dilute hydrochloric acid solution was slowly added dropwise to the composite emulsion to precisely adjust the pH value of the system to 8.0 ± 0.1, thus obtaining the main component, which was then discharged for later use.

[0028] Preparation of the curing agent component: In another 1L container, add 200.0g of deionized water and start stirring. Add 200.0g of polyetheramine curing agent (purchased from Suzhou Hengsite Industrial Co., Ltd.) to the water and stir at 500r / min for 20min until a homogeneous and transparent solution is formed, which is the curing agent component. For field application, mix the main component and the curing agent component at a mass ratio of 10:1, stir for 5min, and then pump into the wellbore.

[0029] Example 2 The specific implementation method is the same as in Example 1, except that the preparation of organosilane-modified yttrium-doped nanoboehmite is different. Step A1: In a 2000mL three-necked flask, add 500.0g of deionized water and heat to 84.0℃. Dissolve 90.0g of aluminum nitrate nonahydrate and 8.0g of yttrium nitrate hexahydrate in 100.0g of deionized water to prepare a mixed salt solution. Use a 2.5mol / L sodium hydroxide solution as a precipitant. While stirring, simultaneously add the mixed salt solution and sodium hydroxide solution, controlling the pH to 8.6. After the addition is complete, age and crystallize at 95.0℃ for 13.0h. Centrifuge the slurry, and wash the solid alternately with deionized water and ethanol until neutral to obtain a wet gel.

[0030] Step A2: The wet gel was dried in a vacuum drying oven at 60.0℃ for 12.0 h to obtain a powder. 70.0 g of this powder was weighed and dispersed in 300.0 g of anhydrous toluene, and sonicated for 30 min. The suspension was transferred to a reaction flask equipped with a reflux condenser and a nitrogen inlet tube, and dry nitrogen gas was bubbled through the bottom at a flow rate of 25 mL / min. 5.6 g of silane coupling agent KH560 was added, and the mixture was heated to 109.0℃ and stirred under reflux for 7.0 h. After the reaction was complete, the solid was centrifuged, washed three times with anhydrous toluene, dried under vacuum at 60.0℃ for 12.0 h, ground, and sieved to obtain compound A.

[0031] Preparation of zirconium aluminum layered double hydroxide modified with titanate coupling agent Step B1: Dissolve 31.0 g of zirconium nitrate hexahydrate and 155.0 g of aluminum nitrate nonahydrate in 200.0 g of 0.1 mol / L nitric acid aqueous solution to obtain solution A. Dissolve 37.0 g of sodium hydroxide and 9.2 g of sodium carbonate in 200.0 g of deionized water to obtain solution B. Under high-speed shear stirring, add both solutions dropwise simultaneously to a reactor containing 100.0 g of deionized water, controlling the addition time at 60 min and maintaining the pH at 9.2. Transfer the resulting slurry to an autoclave and hydrothermally crystallize at 99.0℃ for 13.0 h. After cooling, centrifuge and wash the precipitate until the conductivity of the washing liquid is qualified to obtain a wet filter cake.

[0032] Step B2: The wet filter cake was vacuum dried at 80.0℃ for 12.0 h to obtain a powder. 90.0 g of this powder was weighed and dispersed in 400.0 g of xylene, and sonicated for 30 min. The suspension was transferred to a reaction flask, nitrogen gas was introduced, and 13.5 g of titanate coupling agent KR-138S was added. The mixture was heated to 138.0℃ and stirred under reflux for 9.0 h. After the reaction, the mixture was hot-filtered, and the solid was washed successively with petroleum ether and isopropanol, and then vacuum dried at 60.0℃ for 24.0 h to obtain compound B.

[0033] Preparation of long-term sand control and sand stabilization composite materials for fine sandstone reservoirs Add 800.0g of simulated brine to a mixing vessel, then add 20.0g of clay stabilizer, 15.0g of polycarboxylate dispersant, and 3.0g of corrosion and scale inhibitor sequentially. Stir at 500 rpm for 15 min to dissolve. Add 100.0g of compound A, 80.0g of compound B, and 8.0g of latent curing accelerator sequentially. Increase the stirring speed to 1000 rpm and stir for 60 min, followed by ultrasonic treatment for 30 min. Reduce the stirring speed to 300 rpm and slowly add 250.0g of waterborne epoxy resin emulsion and 40.0g of waterborne polyurethane emulsion dropwise over 30 min. After the addition is complete, continue stirring for 60 min. Adjust the pH of the emulsion to 7.8 with dilute sodium hydroxide solution to obtain the main component. Dissolve 180.0g of polyetheramine curing agent in 180.0g of water and stir until homogeneous to obtain the curing agent component. Mix the main component and curing agent on-site at a mass ratio of 9:1.

[0034] Example 3 The specific implementation method is the same as in Example 1, except that the preparation of organosilane-modified yttrium-doped nanoboehmite is different. Step A1: In a 2000mL three-necked flask, add 500.0g of deionized water and heat to 86.0℃. Dissolve 110.0g of aluminum nitrate nonahydrate and 12.0g of yttrium nitrate hexahydrate in 100.0g of deionized water to prepare a mixed salt solution. Use a 2.5mol / L sodium hydroxide solution as a precipitant. While stirring, simultaneously add the mixed salt solution and sodium hydroxide solution, controlling the pH to 8.9. After the addition is complete, age and crystallize at 96.0℃ for 14.0h. Centrifuge the slurry, and wash the solid alternately with deionized water and ethanol until neutral to obtain a wet gel.

[0035] Step A2: The wet gel was dried in a vacuum drying oven at 61.0℃ for 12.0 h to obtain a powder. 90.0 g of this powder was weighed and dispersed in 300.0 g of anhydrous toluene, and sonicated for 30 min. The suspension was transferred to a reaction flask equipped with a reflux condenser and a nitrogen inlet tube, and dry nitrogen gas was bubbled through the bottom at a flow rate of 35 mL / min. 7.2 g of silane coupling agent KH560 was added, and the mixture was heated to 111.0℃ and stirred under reflux for 10.0 h. After the reaction was complete, the solid was centrifuged, washed three times with anhydrous toluene, dried under vacuum at 61.0℃ for 12.0 h, ground, and sieved to obtain compound A.

[0036] Preparation of zirconium aluminum layered double hydroxide modified with titanate coupling agent Step B1: Dissolve 33.0 g of zirconium nitrate hexahydrate and 165.0 g of aluminum nitrate nonahydrate in 200.0 g of 0.1 mol / L nitric acid aqueous solution to obtain solution A. Dissolve 39.0 g of sodium hydroxide and 9.8 g of sodium carbonate in 200.0 g of deionized water to obtain solution B. Under high-speed shear stirring, add both solutions dropwise simultaneously to a reactor containing 100.0 g of deionized water, controlling the addition time at 60 min and maintaining the pH at 9.8. Transfer the resulting slurry to an autoclave and hydrothermally crystallize at 101.0 °C for 14.0 h. After cooling, centrifuge and wash the precipitate until the conductivity of the washing liquid is qualified to obtain a wet filter cake.

[0037] Step B2: The wet filter cake was vacuum dried at 81.0℃ for 12.0 h to obtain a powder. 110.0 g of this powder was weighed and dispersed in 400.0 g of xylene, and sonicated for 30 min. The suspension was transferred to a reaction flask, nitrogen gas was introduced, and 16.5 g of titanate coupling agent KR-138S was added. The mixture was heated to 142.0℃ and stirred under reflux for 10.0 h. After the reaction, the mixture was hot-filtered, and the solid was washed successively with petroleum ether and isopropanol, and then vacuum dried at 61.0℃ for 24.0 h to obtain compound B.

[0038] Preparation of long-term sand control and sand stabilization composite materials for fine sandstone reservoirs Add 800.0g of simulated brine to a mixing vessel, followed by 40.0g of clay stabilizer, 25.0g of polycarboxylate dispersant, and 8.0g of corrosion and scale inhibitor. Stir at 500 rpm for 15 minutes to dissolve. Then add 200.0g of compound A, 120.0g of compound B, and 15.0g of latent curing accelerator. Increase the stirring speed to 1000 rpm and stir for 60 minutes, followed by ultrasonic treatment for 40 minutes. Reduce the stirring speed to 300 rpm and slowly add 350.0g of aqueous epoxy resin emulsion and 60.0g of aqueous polyurethane emulsion dropwise over 30 minutes. After the addition is complete, continue stirring for 60 minutes. Adjust the pH of the emulsion to 8.2 with dilute hydrochloric acid solution to obtain the main component. Dissolve 220.0g of polyetheramine curing agent in 220.0g of water and stir until homogeneous to obtain the curing agent component. Mix the main component and curing agent on-site at a mass ratio of 11:1.

[0039] Comparative Example 1 The specific implementation method is the same as in Example 1, except that the two modified inorganic compounds (compound A and compound B) are not added to the main component, and the amount of waterborne epoxy resin emulsion is increased accordingly to keep the total mass of the main component approximately the same. Preparation of the main component: 800.0g of simulated formation brine is added to a mixing vessel, followed by 30.0g of clay stabilizer, 20.0g of polycarboxylate dispersant, and 5.0g of corrosion and scale inhibitor, and stirred for 15 minutes to dissolve. 10.0g of latent curing accelerator is added, and the mixture is stirred at high speed and ultrasonically treated for 30 minutes. Subsequently, 450.0g of waterborne epoxy resin emulsion and 50.0g of waterborne polyurethane emulsion are added dropwise. The subsequent stirring and pH adjustment steps are exactly the same as in Example 1, yielding the main component. The preparation of the curing agent component is the same as in Example 1.

[0040] Comparative Example 2 The specific implementation method is the same as in Example 1, except that only organosilane-modified yttrium-doped nano-boehmite (compound A) is added to the main component, and titanate coupling agent-modified zirconium aluminum layered double hydroxide (compound B) is not added. Preparation of the main component: 800.0 g of simulated formation brine was added to a mixing vessel, followed by 30.0 g of clay stabilizer, 20.0 g of polycarboxylate dispersant, and 5.0 g of corrosion and scale inhibitor, and stirred until dissolved. 150.0 g of compound A and 10.0 g of latent curing accelerator were added, and the mixture was stirred at high speed and ultrasonically treated for 30 min. Subsequently, 400.0 g of aqueous epoxy resin emulsion and 50.0 g of aqueous polyurethane emulsion were added dropwise, and the subsequent steps were the same as in Example 1 to obtain the main component. The preparation of the curing agent component was the same as in Example 1.

[0041] Comparative Example 3 The specific implementation method is the same as in Example 1, except that the mixing mass ratio of the main agent component and the curing agent component during on-site construction is changed. The preparation methods of the main agent component and the curing agent component are exactly the same as in Example 1. However, during simulated on-site construction, the two are mixed and used at a mass ratio of 20:1.

[0042] Performance testing The long-term sand control and sand stabilization composite materials for fine sandstone reservoirs prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing according to the following method, which included the following steps: First, test cores were prepared: Quartz sand with a particle size of 0.100 mm to 0.212 mm was uniformly mixed with kaolin powder (10.0% by mass, particle size less than 0.075 mm) to simulate fine sandstone formation sand. This mixed sand was loaded into a standard stainless steel core tube with an inner diameter of 25.0 mm and a length of 60.0 mm, and axially compacted under a constant pressure of 5.0 MPa to prepare an unconsolidated artificial core column with a porosity of 35.0% ± 2.0%. Using nitrogen as a medium, the initial gas permeability of the artificial core was measured at an inlet pressure of 0.5 MPa and recorded as K0, in mD. Subsequently, material processing was performed: The main agent and curing agent to be tested were thoroughly mixed according to the mass ratio described in the claims (10:1 in Examples and Comparative Examples 1 and 2, and 20:1 in Comparative Example 3), and immediately injected into the core at a constant rate of 0.5 mL / min, with a total injection volume of 1.5 times the core pore volume. After injection, the two ends of the core were sealed and placed in a high-temperature and high-pressure curing autoclave. The core was cured for 72.0 hours under a confining pressure of 10.0 MPa and a temperature of 100.0℃ to simulate the downhole environment and allow the composite material to fully solidify.

[0043] Four performance tests were conducted after maintenance: First, the uniaxial compressive strength test of the consolidated core column was conducted. The consolidated core column was carefully removed from the tube and axially loaded at a constant displacement rate of 0.5 mm / min using a universal testing machine until the core failed. The maximum load was recorded and the compressive strength was calculated in MPa. Each sample was tested three times and the average value was taken.

[0044] Second, the permeability retention rate test involves reassembling the core fragments after the strength test back into the core holder and measuring the gas permeability K1 after solidification under the exact same conditions as the K0 measurement (nitrogen, 0.5 MPa inlet pressure). The permeability retention rate is calculated as (K1 / K0)×100%.

[0045] Third, the strength retention rate test after high temperature aging: another set of core samples prepared and solidified under the same conditions were completely immersed in simulated formation brine with a salinity of 30000 mg / L and aged in an oven at 120.0℃ under normal pressure for 30 days. After aging, the samples were taken out, washed and dried, and their uniaxial compressive strength was tested again according to the above method. The formula for calculating the strength retention rate after aging is (strength after aging / strength before aging) × 100%.

[0046] Fourth, the fine sand yield test was conducted using a short core tube with an inner diameter of 25.0 mm and a length of 30.0 mm. The same sand-soil mixture was filled and the same material was injected and cured using the same process. The solidified short core was then connected to a fluid displacement system. Simulated formation water was continuously injected at a flow rate of 2.0 mL / min under a back pressure of 0.5 MPa and an ambient temperature of 100.0℃ for 2.0 h. All effluent was collected, filtered through a 0.045 μm filter membrane, dried, and weighed to obtain the mass of flushed solids. The sand yield was calculated using the formula: (mass of flushed solids / total mass of sand filling the core) × 100%.

[0047] Test results: Table 1: Test results of each embodiment and comparative example ; As can be seen from Table 1, the composite materials prepared in Examples 1-3 comprehensively and significantly overcome the key defects of existing sand control technologies compared with the comparative examples.

[0048] In addressing the core contradiction of balancing consolidation strength and formation permeability, the examples demonstrated exceptional balancing capabilities: their uniaxial compressive strength ranged from a high of 14.1 MPa to a low of 10.8 MPa, significantly exceeding the 4.2 MPa of Comparative Example 1 (which did not use the modified compound), proving that the two modified inorganic compounds contributed a decisive reinforcing effect. Simultaneously, the permeability retention rates of the examples remained at a high level of 75.0-81.5%, significantly better than the 65.2% of Comparative Example 2 (which used only compound A). This indicates that while the titanate-modified layered double hydroxide provides reinforcement, its unique layered structure effectively maintains pore channels, thus synergistically achieving the ideal effect of "strong without clogging." Regarding the consolidation effect on fine silt, the examples performed exceptionally well, with sand yields of only 0.02-0.05%, more than an order of magnitude lower than all comparative examples. This directly confirms the efficient encapsulation and anchoring ability of organosilane-modified nano-boehmite for fine particles, solving the problem of easy migration of fine silt.

[0049] Regarding the issues of insufficient stability and short effective period in high-temperature and high-salinity reservoir environments, the strength retention rate of the examples after accelerated aging at 120°C for 30 days was as high as 86.1-90.2%, which is much higher than the 62.5% of Comparative Example 1 and 78.9% of Comparative Example 2. This fully demonstrates the excellent thermal stability of the two modified compounds themselves and the outstanding anti-aging ability of the hybrid network formed with organic resin, indicating a longer effective sand-proof life.

[0050] In summary, the test data, from four dimensions—mechanical properties, reservoir protection, target sand grain consolidation, and long-term durability—conclusively demonstrate that this invention, through the synergistic design of two innovative modified compounds, has successfully overcome the bottlenecks of existing technologies.

[0051] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a long-lasting sand-fixing and sand-stabilizing composite material for fine sandstone reservoirs, characterized in that the steps include... include: S1. By weight, add brine to a mixing vessel, add 1-5 parts of clay stabilizer, stir, then add 1-3 parts of polycarboxylate dispersant and 0.1-10 parts of corrosion and scale inhibitor, stir, add 10-25 parts of organosilane-modified yttrium-doped nano-boehmite, 5-15 parts of titanate coupling agent-modified zirconium aluminum layered double hydroxide, and 0.5-2 parts of curing accelerator, stir, and sonicate to obtain a suspension; add 20-40 parts of waterborne epoxy resin emulsion and 2-8 parts of waterborne polyurethane emulsion dropwise to the suspension, continue stirring to obtain a composite emulsion; S2. Under stirring, adjust the pH value of the composite emulsion to 7.5-8.5 to obtain the main component; dissolve the polyetheramine curing agent in water and stir to obtain the curing agent component; the long-term sand control and sand fixation composite material for fine sandstone reservoirs is composed of the main component and the curing agent component.

2. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 1, characterized in that, In step S1, the ultrasonic treatment time is 30-60 minutes.

3. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 1, characterized in that, In step S2, the mass ratio of the main agent component to the curing agent component is (8-12):

1.

4. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 1, characterized in that, The preparation method of the organosilane-modified yttrium-doped nanoboehmite includes: A1. By weight, add deionized water to a three-necked flask and heat to 84-86℃. While stirring, add dropwise a mixed salt solution formed by dissolving 80-120 parts of aluminum nitrate nonahydrate and 5-15 parts of yttrium nitrate hexahydrate in deionized water, along with sodium hydroxide solution, to the three-necked flask to adjust the pH to 8.5-9.

0. After the addition is complete, age and crystallize at 94-96℃ to obtain a slurry. Centrifuge the slurry to obtain a solid product. Wash the solid product alternately with deionized water and ethanol to obtain a wet gel. A2. The wet gel was dried in a vacuum drying oven at 58-62℃ to obtain dry yttrium-doped boehmite powder. The dried yttrium-doped boehmite powder was redispersed in anhydrous toluene and sonicated to obtain a suspension. The suspension was transferred to a reaction flask equipped with a reflux condenser. Dry nitrogen gas was continuously bubbled through the bottom of the reaction flask. Silane coupling agent KH560 was added, and dry nitrogen gas was introduced. The mixture was heated to 108-112℃ and stirred under reflux. The methanol generated in the reaction was discharged through the upper end of the condenser with the nitrogen gas flow to obtain the reaction mixture. The reaction mixture was centrifuged, washed with anhydrous toluene, and finally dried in a vacuum drying oven at 58-62℃ and ground.

5. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 4, characterized in that, In step A1, the aging and crystallization time at 94-96℃ is 12-14 hours.

6. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 4, characterized in that, In step A2, the reaction time is 6-12 hours after heating to 108-112℃ and stirring under reflux.

7. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 1, characterized in that, The preparation method of the titanate coupling agent modified zirconium aluminum layered double hydroxide includes: B1. By weight, dissolve 30-34 parts of zirconium nitrate hexahydrate and 150-170 parts of aluminum nitrate nonahydrate in an aqueous nitric acid solution to obtain solution A; dissolve sodium hydroxide and sodium carbonate in deionized water to obtain solution B; add solutions A and B dropwise to a reactor containing deionized water under stirring, adjust the pH to 9.0-10.0, and obtain a reaction solution; transfer the reaction solution to a high-pressure reactor and perform hydrothermal crystallization at 98-102℃; after natural cooling, collect the precipitate by centrifugation, wash the precipitate with deionized water, and obtain a wet filter cake; B2. Dry the wet filter cake in a vacuum drying oven at 78-82℃ to obtain a dry powder; redisperse the dry powder in xylene and sonicate to obtain a suspension; transfer the suspension to a reaction flask, add titanate coupling agent KR-138S, purge with nitrogen, and heat to 135-145℃ under reflux with stirring; after the reaction is complete, filter to obtain a solid product, wash the solid product with isopropanol, and finally dry it in a vacuum drying oven at 58-62℃.

8. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 7, characterized in that, In step B1, the hydrothermal crystallization time is 12-14 hours at 98-102℃.

9. The preparation method of the long-term sand control and sand stabilization composite material for fine sandstone reservoirs according to claim 7, characterized in that, In step B2, the reaction is carried out under reflux at 135-145℃ for 8-10 hours.

10. A long-lasting sand control and sand stabilization composite material for fine sandstone reservoirs, characterized in that, The long-term sand control and sand stabilization composite material for fine sandstone reservoirs is prepared according to any one of claims 1-9.