Steam injection thermal employing aerogel nanoparticles and stable foam profile control system

Abstract

The application belongs to the technical field of oil and gas field development, and specifically discloses a steam injection heat adopting aerogel nanoparticle and stable foam profile control system. The aerogel nanoparticle of the application comprises the following steps: preparation of SiO2 sol; preparation of SiO2 gel; aging treatment of SiO2 gel; hydrophobic modification treatment of SiO2 gel; and vacuum drying treatment of SiO2 gel. The application also provides a stable foam profile control system comprising the aerogel nanoparticle. The aerogel nanoparticle prepared by the application is a multifunctional material with a three-dimensional porous network structure, and has excellent heat insulation performance and adsorption performance. By using the aerogel nanoparticle to stabilize the foam, the high-permeability channels of steam channeling are plugged, and the steam channeling is controlled. Meanwhile, by virtue of the excellent heat insulation performance of the aerogel, the heat loss of steam in the near-wellbore zone is reduced, the deep formation heat transfer is strengthened, the steam heating radius is expanded, and the heat utilization efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically relating to a steam injection thermal system using aerogel nanoparticles and stable foam profile control. Background Technology

[0002] There are two prominent problems in the development of steam injection for heavy oil: First, due to the heterogeneity of the formation, steam tends to flow along high-permeability layers, resulting in a small thermal sweep radius; second, steam suffers significant heat loss near the wellbore, failing to effectively heat deeper formations, leading to low thermal utilization and poor steam injection thermal recovery. Therefore, controlling steam flow and increasing the steam thermal sweep radius are key to improving the effectiveness of steam injection.

[0003] Injecting heat-resistant foam into the formation to adjust the steam injection profile and control steam flow rate are common methods for suppressing steam channeling. However, conventional foams have poor stability in high-temperature formation environments and are prone to collapse, resulting in a weak ability to suppress steam channeling. Therefore, improving the stability of foams is particularly important for controlling steam channeling.

[0004] Chinese patent application CN 201410004181.5 provides a foam system and its preparation method that improves foam stability and strength by using hydrophobic clay particles. The hydrophobic clay particles can adhere to the surface of the foam liquid film to form a dense shell, thereby improving the foam strength, inhibiting the drainage of the liquid film, preventing the liquid film from thinning, and thus improving the stability of the foam.

[0005] Chinese patent application CN 201911338872.8 provides a reinforced foam system based on the synergistic stabilization of rice husk ash. The foam system is prepared using anionic surfactants and rice husk ash. The rice husk ash can be adsorbed onto the surface of the liquid film to form a dense layer, thereby inhibiting foam drainage and gas diffusion. At the same time, it can also increase the viscosity of the foam phase, playing a role in profile regulation.

[0006] Chinese patent application CN 201810179234.5 provides a reinforced foam system based on the synergistic stabilization of graphite oxide particles, which utilizes graphite oxide particles and cationic surfactants to synergistically stabilize foam and improve oil recovery.

[0007] In addition, Chinese patent applications CN201210223060.0 and CN201510600689.6 provide a foam system stabilized by modified nano-silica and inorganic fine particles, which slows down liquid film drainage and improves foam stability through the synergistic effect of particles and foaming agents.

[0008] All of the above systems utilize the synergistic effect of particles and foaming agents to slow down liquid film drainage and improve foam stability, which can be used to control gas or steam cross-flow. After the foam collapses, the particles remaining in the formation can only play a simple role in accumulation and sealing, but they have no beneficial effect on reducing steam heat loss or expanding the steam heating radius. Summary of the Invention

[0009] The purpose of this invention is to provide aerogel nanoparticles for steam injection and a stable foam profile control system containing these particles. The prepared aerogel nanoparticles are a multifunctional material with a three-dimensional porous network structure, possessing excellent thermal insulation and adsorption properties. By stabilizing the foam with aerogel nanoparticles, high-permeability channels for steam cross-flow are blocked, controlling steam cross-flow. Simultaneously, the excellent thermal insulation properties of the aerogel reduce heat loss of steam in the near-wellbore zone, enhance heat transfer in deep formations, expand the steam heating radius, and improve thermal utilization efficiency.

[0010] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0011] On the one hand, a method for preparing aerogel nanoparticles for steam injection heating is provided, comprising the following steps:

[0012] S1: Preparation of SiO2 sol;

[0013] S2: Preparation of SiO2 gel;

[0014] S3: Aging treatment of SiO2 gel;

[0015] S4: Hydrophobic modification treatment of SiO2 gel;

[0016] S5: Vacuum drying treatment of SiO2 gel.

[0017] Furthermore, the preparation of the SiO2 sol includes: dissolving the silicon source precursor in anhydrous ethanol, adding water and hydrochloric acid, adjusting the pH of the solution to 2-3, and reacting at room temperature to obtain the SiO2 sol.

[0018] Furthermore, the preparation of the SiO2 sol includes: dissolving the silicon source precursor in anhydrous ethanol, adding water, adjusting the pH of the solution to 2-3 with 0.1 mol / ml hydrochloric acid, and stirring the mixture at 600 r / min for 20 min at room temperature on a magnetic stirrer to obtain the SiO2 sol.

[0019] Furthermore, the volume ratio of the silicon source precursor, anhydrous ethanol, water, and hydrochloric acid is 0.5-0.9:4:8.5:0.1-0.3.

[0020] Furthermore, the silicon source precursor is methyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), water glass, polysiloxane E-40, and oxyalkanol oxide O. x M(OR) y At least one of XSi(OR)3 (where X is a ligand organic group). Methyl orthosilicate, tetraethyl orthosilicate,

[0021] Furthermore, the O x M(OR) y The form is C4H9OC2H4OH or C4H8OHOCH2OH; the form is C2H4NO2Si(OCH3)3 or C6H 11 N2Si(OCH2COOH).

[0022] Furthermore, the preparation of the SiO2 gel includes: adding ammonia water to the SiO2 sol, adjusting the pH of the solution to neutral or weakly alkaline conditions, and reacting at room temperature to obtain the SiO2 gel.

[0023] Furthermore, the preparation of the SiO2 gel includes: adding 0.1 mol / L ammonia water to the SiO2 sol to adjust the pH value of the solution to the range of 7-8, stirring, and then letting it stand until it loses its fluidity, thereby obtaining the SiO2 gel.

[0024] Furthermore, the aging treatment of the SiO2 gel includes: immersing the SiO2 gel obtained above in anhydrous ethanol at room temperature for 8-24 hours, discarding the liquid in the mixture, and adding n-hexane solution to exchange the pure water in the wet gel.

[0025] Furthermore, the hydrophobic modification treatment of the SiO2 gel includes: using trimethylchlorosilane to perform hydrophobic modification on the aged SiO2 gel, and attaching hydrophobic trimethylsiloxy groups to the gel surface.

[0026] Furthermore, the vacuum drying process of the SiO2 gel includes: heat-treating the SiO2 gel under vacuum at 80-100°C for 6-8 hours to remove water molecules from the gel.

[0027] Furthermore, the water is surface water or groundwater with a mineralization of <10000 mg / L.

[0028] Furthermore, the preparation method of the aerogel nanoparticles for steam injection heating includes the following steps:

[0029] S1: Preparation of SiO2 sol: Dissolve 0.5-0.9 parts of silicon source precursor in 4 parts of anhydrous ethanol, add 8.5 parts of water, adjust the pH of the solution to 2-3 with hydrochloric acid, and react at room temperature to obtain SiO2 sol;

[0030] S2: Preparation of SiO2 gel: 0.1 mol / L ammonia water was added to the SiO2 sol, the pH value was adjusted to the range of 7-8 and the reaction was carried out at room temperature to obtain SiO2 gel;

[0031] S3: Aging treatment of SiO2 gel: Immerse the SiO2 gel in 40 parts of ethanol for aging for 8 hours to 1 day;

[0032] S4: Hydrophobic modification of SiO2 gel: Hydrophobic modification of the aged SiO2 gel was performed using 1 part of trimethylchlorosilane.

[0033] S5: Vacuum drying treatment of SiO2 gel: The hydrophobically modified SiO2 gel is heat-treated at 80℃ in vacuum for 6-8 hours to remove water molecules from the gel.

[0034] S6: Nanoparticles with the desired particle size and specific surface area are obtained through nanoprocessing of stirring, pulverizing, and ultrafine mechanical pulverization.

[0035] This invention uses hydrochloric acid and ammonia to adjust the pH. Since both hydrochloric acid and ammonia are volatile substances, the subsequent heat treatment process can remove introduced impurities and reduce their impact on the finished product's performance. Stirring during the reaction promotes homogenization of the sol mixture and ensures sufficient contact between reactants, accelerating sol formation. Anhydrous ethanol is selected in this invention due to its excellent dissolving properties and rapid evaporation. The trimethylchlorosilane used in this invention has a low boiling point, is colorless, has low toxicity, high hydrophobicity, and a high overall utilization index.

[0036] The aerogel nanoparticles prepared by this invention have high purity and low heterogeneity. The reaction process is carried out in solution, the reaction rate is easy to control, and it can be carried out at room temperature and pressure with few byproducts.

[0037] On the other hand, the present invention also provides a steam injection heating aerogel nanoparticle stabilized foam profile control system, including the aerogel nanoparticles.

[0038] Furthermore, the steam injection heating aerogel nanoparticle stabilized foam profile control system comprises the following components by weight: 0.5 to 1 part foaming agent, 0.3 to 0.7 parts aerogel nanoparticles, and 100 parts water.

[0039] Furthermore, the foaming agent is a high-temperature resistant surfactant with 10-16 carbon atoms and a temperature resistance >250℃.

[0040] Furthermore, the foaming agent is a petroleum sulfonate or an alkylbenzene sulfonate.

[0041] Furthermore, this invention also provides a method for preparing a steam injection heat-stabilized foam profile control system using aerogel nanoparticles, comprising the following steps:

[0042] Step 1: Heat-treat the aerogel nanoparticles;

[0043] Step 2: Disperse the heat-treated aerogel nanoparticles in anhydrous ethanol, add water, stir, ultrasonically disperse, and centrifuge to separate the solid phase;

[0044] Step 3: Add the solid phase to water, then add a foaming agent to obtain a mixture. Stir to form foam, or inject the mixture and gas into a foam generator.

[0045] Furthermore, in step 1, the heat treatment temperature is 200-250℃ and the heat treatment time is 1-2 hours, so that the air adsorbed in the pores of the aerogel is desorbed.

[0046] Furthermore, in step 2, the amount of anhydrous ethanol added is 10-15 ml / g, and the ultrasonic dispersion time is 8-10 min.

[0047] Furthermore, in step 3, the mass concentration of aerogel nanoparticles in the mixture is 0.3-0.7%, and the mass concentration of foaming agent is 0.5-1%.

[0048] Furthermore, the stirring in step 3 is carried out using the Waring Blender method, with a stirring speed of 6000-8000 rpm and a stirring time of 5 minutes.

[0049] Furthermore, the gas mentioned in step 3 is nitrogen, carbon dioxide, or flue gas, and the volume ratio of the mixture to the gas is 1:2 to 1:4.

[0050] The present invention has the following beneficial effects:

[0051] (1) The aerogel nanoparticles prepared in this invention have a specific surface area of ​​700-900 m². 2 / g, density 0.20g / cm³ 3 The particle size is 20-40 nm, the porosity is about 95%, and the pore size is 40-70 nm.

[0052] (2) The aerogel nanoparticles prepared in this invention are a multifunctional material with a three-dimensional porous network structure, possessing excellent thermal insulation and adsorption properties. The aerogel nanoparticles adhere to the surface of the foam liquid film, forming a network of wrinkles that act as a supporting framework for the foam, slowing down the foam drainage rate and hindering foam aggregation. Simultaneously, their excellent thermal insulation properties enhance the stability of the foam in high-temperature environments.

[0053] (3) In the foam profile control system of the present invention, the foam generates additional resistance by accumulating in the high-permeability layer, while the aerogel nanoparticles are retained in the formation. The combined effect of these two factors controls steam channeling and expands the steam reach. After the foam collapses, the aerogel nanoparticles, due to their extremely low density, are immediately adsorbed onto the rock pore walls. Due to their excellent thermal insulation properties, they hinder heat exchange between steam and formation rocks, reduce heat loss of steam in the near-wellbore zone, promote the expansion of the steam chamber into the deeper parts of the reservoir, expand the heating radius, and improve the thermal utilization rate. Attached Figure Description

[0054] Figure 1 The electron microscopy test results of aerogel nanoparticles in Example 1 of this invention;

[0055] Figure 2 These are the test results of foam volume and half-life in Example 1 of this invention;

[0056] Figure 3 This is the result of the foam volume change over time in Comparative Example 3 of the present invention;

[0057] Figure 4 The changes in injection pressure and recovery rate of the aerogel foam system at different displacement stages in Example 4;

[0058] Figure 5 The effects of aerogel foam collapse on steam percolation heat transfer in Examples 5 and 6 of the present invention are shown in (a) percolation heat transfer curve under the action of aerogel nanoparticles, and (b) steam percolation heat transfer curve.

[0059] Figure 6 The adsorption-desorption curve of the aerogel nanoparticles in Example 1 of this invention is shown.

[0060] Figure 7 This is a schematic diagram of the contact angle of the aerogel nanoparticles in Embodiment 1 of the present invention. Detailed Implementation

[0061] The present invention will be described below with reference to specific embodiments to make the technical solution of the present invention easier to understand and master, but the present invention is not limited thereto. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are all commercially available.

[0062] Example 1

[0063] A method for preparing aerogel nanoparticles for steam injection heating includes the following steps:

[0064] S1: Preparation of SiO2 sol: 0.8 parts of methyl orthosilicate were dissolved in 4 parts of anhydrous ethanol, and 8.5 parts of water were added. The pH of the solution was adjusted to 2-3 with 0.1 mol / ml hydrochloric acid. The mixture was stirred at 600 r / min for 20 min at room temperature to obtain SiO2 sol. The water was surface water with a mineralization of <10000 mg / L.

[0065] S2: Preparation of SiO2 gel: Add 0.1 mol / L ammonia water to the SiO2 sol, adjust the pH value to the range of 7-8 and react at room temperature to obtain SiO2 gel;

[0066] S3: Aging treatment of SiO2 gel: The SiO2 gel was soaked in 40 parts of ethanol for 1 day for aging.

[0067] S4: Hydrophobic modification of SiO2 gel: Hydrophobic modification of the aged SiO2 gel was performed using 1 part of trimethylchlorosilane.

[0068] S5: Vacuum drying treatment of SiO2 gel: The hydrophobically modified SiO2 gel was heat-treated at 80℃ in a vacuum for 8 hours to remove water molecules from the gel.

[0069] S6: Nanoparticles with the desired particle size and specific surface area are obtained through nanoprocessing of stirring, pulverizing, and ultrafine mechanical pulverization.

[0070] Performance testing

[0071] Density test

[0072] The density of the particles was measured using a specific gravity bottle. Specific procedures are omitted. Let the weight of the specific gravity bottle filled with ultrapure water be M1 (g), the weight of the particles be M2 (g), and the weight of the two particles after adding them to the specific gravity bottle filled with water be M3 (g). Then, the density of the particles is:

[0073]

[0074] Particle size testing

[0075] The test results were obtained using TEM transmission electron microscopy. Figure 1 .

[0076] Pore ​​size and specific surface area testing

[0077] The specific surface area and pore size distribution of the samples were tested using an N2 adsorption-desorption apparatus. The test results (e.g.) Figure 6The adsorption-desorption curves obtained (as shown) were used to calculate pore size and specific surface area using the BJH formula and the BET method. According to the classification of nitrogen adsorption-desorption isotherms by the International Union of Theoretical and Applied Chemistry, this type of adsorption isotherm belongs to the type IV isotherm. The pore size distribution is in the range of 40-70 nm, and the specific surface area is approximately 800 m². 2 / g.

[0078] Wettability test

[0079] When water droplets are placed on the surface of an aerogel material, a contact angle greater than 90° is measured, indicating that the hydrophobic modifier has successfully transformed the aerogel into a hydrophobic material. A schematic diagram of the contact angle is shown below. Figure 7 As shown.

[0080] Porosity testing

[0081] A block of aerogel with mass m1 is weighed in air, completely immersed in kerosene for 1 hour, then removed, rinsed with n-hexane solution to remove residual oil droplets, and allowed to air dry. Its mass at this point is measured as m2. The block of aerogel, now fully saturated with kerosene, is then immersed again in a graduated cylinder filled with kerosene. The mass of kerosene that overflows from the cylinder is V. The porosity of the aerogel is expressed as:

[0082]

[0083] The properties of the aerogel nanoparticles prepared in Example 1 are shown in Table 1.

[0084] Table 1. Relevant physical properties of SiO2 aerogel nanoparticles

[0085]

[0086] The foam profile control system consists of the following components in parts by weight: 0.1 to 0.9 parts of aerogel nanoparticles from Example 1, 1 part of high-temperature foaming agent petroleum sulfonate (Jiangsu Haian Petrochemical Plant, model DMPS-PB), and 100 parts of distilled water.

[0087] The preparation method is as follows:

[0088] Step 1: Heat-treat the hydrophobic aerogel nanoparticles at 250℃ for 1 hour;

[0089] Step 2: Weigh 0.1g of aerogel nanoparticles, add 10ml of anhydrous ethanol and 50ml of distilled water to each gram of aerogel nanoparticles, sonicate for 10min, and centrifuge for 30min to obtain the solid phase.

[0090] Step 3: Add 100ml of distilled water and 1g of petroleum sulfonate to the solid phase obtained by centrifugation;

[0091] Step 4: Use a Waring Blender to stir the mixture at 8000 rpm with nitrogen gas (the volume ratio of the mixture to nitrogen gas is 1:3) for 5 minutes to obtain an aerogel nanoparticle stable foam system. Pour the obtained foam system into a graduated cylinder to measure the foam volume and half-life.

[0092] By varying the amount of hydrophobic aerogel nanoparticles added, stable foam systems of aerogel nanoparticles were prepared at mass concentrations of 0.3%, 0.5%, 0.7%, and 0.9%, respectively. The foam volume and half-life were measured, and the results are as follows: Figure 2 As shown in the figure. It has been verified that when the mass fraction of aerogel nanoparticles is 0.5wt%, the foam volume is the largest, the half-life is the longest, and the foam is the most stable.

[0093] Example 2

[0094] A method for preparing aerogel nanoparticles for steam injection heating includes the following steps:

[0095] S1: Preparation of SiO2 sol: 0.6 parts of polysiloxane E-40 were dissolved in 4 parts of anhydrous ethanol, and 8.5 parts of water were added. The pH of the solution was adjusted to 2-3 with 0.1 mol / ml hydrochloric acid. The mixture was stirred at 600 r / min for 20 min at room temperature to obtain SiO2 sol. The water was groundwater with a mineralization of <10000 mg / L.

[0096] S2: Preparation of SiO2 gel: Add 0.1 mol / L ammonia water to the SiO2 sol, adjust the pH value to the range of 7-8 and react at room temperature to obtain SiO2 gel;

[0097] S3: Aging treatment of SiO2 gel: The SiO2 gel was soaked in 40 parts of ethanol for 16 hours for aging.

[0098] S4: Hydrophobic modification of SiO2 gel: Hydrophobic modification of the aged SiO2 gel was performed using 1 part of trimethylchlorosilane.

[0099] S5: Vacuum drying treatment of SiO2 gel: The hydrophobically modified SiO2 gel was heat-treated at 80℃ in a vacuum for 8 hours to remove water molecules from the gel.

[0100] S6: Nanoparticles with the desired particle size and specific surface area are obtained through nanoprocessing of stirring, pulverizing, and ultrafine mechanical pulverization.

[0101] The foam profile control system consists of the following components in parts by weight: 0.5 parts hydrophobic aerogel nanoparticles, 0.5 parts high-temperature resistant foaming agent sodium alkylbenzene sulfonate, and 100 parts distilled water.

[0102] The preparation method is as follows:

[0103] Step 1: Heat-treat the hydrophobic aerogel nanoparticles at 250℃ for 1 hour;

[0104] Step 2: Weigh 0.5g of aerogel nanoparticles, add 6ml of anhydrous ethanol and 50ml of distilled water, sonicate for 10min, and centrifuge for 30min to obtain the solid phase;

[0105] Step 3: Add 100 ml of distilled water and 1 g of the preferred high-temperature foaming agent alkylbenzene sulfonate to the solid phase obtained by centrifugation;

[0106] Step 4: Use a Waring Blender stirrer to introduce nitrogen gas at 8000 rpm (the volume ratio of the mixture to nitrogen gas is 1:2) and stir for 5 minutes to obtain an aerogel nanoparticle stabilized foam system.

[0107] Step 5: Pour the prepared foam system into a graduated cylinder, place it in a 90℃ environment, and record the change in foam volume over time.

[0108] Comparative Example 3

[0109] The foam profile control system consists of the following components in parts by weight: 0.5 parts hydrophilic nanoparticles (Shanghai Wokai Chemical Reagent Co., Ltd., National Drug Registration Number: XW1129455252, CSA Number: 112945-52-5, specific surface area: 400 m²). 2 / g), 0.5 parts high-temperature foaming agent HY-4, 100 parts distilled water.

[0110] Step 1: [The following appears to be a separate, unrelated sentence:] Density 0.20 g / cm 3 Add 0.5g of hydrophilic nanoparticles with a particle size of 20-40nm to 100mL of distilled water, and add 1g of high-temperature foaming agent HY-4;

[0111] Step 2: Use a Waring Blender stirrer to introduce nitrogen gas at 8000 rpm (the volume ratio of the mixture to nitrogen gas is 1:2) and stir for 5 minutes to obtain a hydrophilic nanoparticle stable foam system.

[0112] Step 3: Pour the prepared foam system into a graduated cylinder, place it in a 90℃ environment, and record the change in foam volume over time.

[0113] The foam volume change curves of the foam systems prepared in Example 2 and Comparative Example 3 over time are shown below. Figure 3 As shown. By Figure 3 It is known that the invented aerogel nanoparticle stabilized foam system has excellent foam stability at high temperature, with a foam life of 90 min, compared to 30 min for the conventional SiO2 nanoparticle stabilized foam system, which is 3 times better.

[0114] Example 4

[0115] The foam profile control system consists of the following components in parts by weight: 0.5 parts hydrophobic aerogel nanoparticles (prepared in Example 1), 1 part high-temperature foaming agent HY-4, and 100 parts distilled water, prepared in the same way as in Example 1.

[0116] Step 1: Fill the sand core with water. The sand core has a diameter of 25mm, a length of 600mm, a porosity of 40.1%, and a permeability of 2231.8mD. Install three temperature probes at distances of 15cm, 30cm, and 45cm from the inlet.

[0117] Step 2: Fill the sandstone core with 118 mL of saturated heavy oil. The viscosity of the heavy oil at 50℃ is 3000 mPa·s.

[0118] Step 3: Inject steam into the sand-filled core for steam drive. The steam temperature is 200℃ and the steam flow rate is 1.5ml / min.

[0119] Step 4: After steam is driven to the outlet end and the water content reaches 98%, 11.8 mL of a mixture containing 0.5 wt% aerogel nanoparticles and 1% HY-4 foaming agent is injected at a rate of 0.4 mL / min. At the same time, 47.2 mL of nitrogen is injected at a rate of 1.6 mL / min. The mixture and nitrogen are injected into the sand-filled core after foaming by the foam generator.

[0120] Step 5: Steam is then injected again for steam drive, and the changes in injection pressure and recovery rate are as follows. Figure 4 As shown in the figure, the results indicate that after the injection of aerogel nanoparticles to stabilize the foam drive, the injection pressure increased rapidly, indicating that the foam and nanoparticles have formed an effective seal in the sand layer, effectively controlling steam cross-flow.

[0121] Example 5

[0122] The foam profile control system consists of the following components in parts by weight: 0.5 parts hydrophobic aerogel nanoparticles (prepared in Example 1), 1 part high-temperature foaming agent HY-4, and 100 parts distilled water, prepared in the same way as in Example 1.

[0123] Step 1: Fill the sand core with water. The sand core has a diameter of 25mm, a length of 600mm, a porosity of 39.8%, and a permeability of 1763.6mD. Install three temperature probes at distances of 15cm, 30cm, and 45cm from the inlet.

[0124] Step 2: Inject steam into the sand-filled core for steam drive. The steam temperature is 200℃, the steam flow rate is 1.5ml / min, and the ambient temperature of the sand-filled core is 100℃.

[0125] Step 3: After steam is driven to the outlet end where the moisture content reaches 98%, inject 50 mL of a mixture containing 0.5 wt% aerogel nanoparticles and 1% HY-4 foaming agent at a rate of 2 mL / min.

[0126] Step 4: Then, steam is injected again for steam drive, and the temperature changes at each measuring point are as follows. Figure 5 As shown in (a).

[0127] Comparative Example 6

[0128] The foam profile control system consists of the following components by weight: 1 part high-temperature foaming agent HY-4, and 100 parts distilled water.

[0129] The preparation method of the foam profile control system is as follows: add high-temperature foaming agent HY-4 to distilled water and mix.

[0130] Step 1: Fill the sand core with water. The sand core has a diameter of 25mm, a length of 600mm, a porosity of 39.6%, and a permeability of 1782.3mD. Install three temperature probes at distances of 15cm, 30cm, and 45cm from the inlet.

[0131] Step 2: Inject steam into the sand-filled core for steam drive. The steam temperature is 200℃, the steam flow rate is 1.5ml / min, and the ambient temperature of the sand-filled core is 100℃.

[0132] Step 3: After steam is driven to the outlet end where the moisture content reaches 98%, inject 50 mL of a mixture containing 1% HY-4 foaming agent at a rate of 2 mL / min.

[0133] Step 4: Then, steam is injected again for steam drive, and the temperature changes at each measuring point are as follows. Figure 5 As shown in (b).

[0134] Compared with Example 5 and Comparative Example 6, after injecting the aerogel nanoparticle foam liquid slug, the temperature at the inlet and temperature measuring point 1 decreased, while the temperature at temperature measuring points 2 and 3 deep in the core increased significantly. This shows that the aerogel nanoparticles carried by the foam liquid prepared in this invention can be adsorbed onto the pore wall to form a heat insulation layer, suppress the condensation and heat dissipation at the steam injection end, bring more heat into the deep part of the model, and expand the heating radius.

[0135] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A method of preparing steam flood heat gas agglomerated nanoparticles, characterized by, The steps are as follows: S1: Preparation of SiO2 sol: The silicon source precursor was dissolved in anhydrous ethanol, water and hydrochloric acid were added, the pH of the solution was adjusted to 2-3, and the mixture was stirred at 600 r / min for 20 min at room temperature to obtain SiO2 sol; the mass ratio of silicon source precursor, anhydrous ethanol, water and hydrochloric acid was 0.5-0.9:4:8.5:0.1-0.3; S2: Preparation of SiO2 gel; S3: Aging treatment of SiO2 gel: Immerse the SiO2 gel in ethanol for 8-24 hours; S4: Hydrophobic modification treatment of SiO2 gel; S5: Vacuum drying treatment of SiO2 gel; The hydrophobic modification treatment of the SiO2 gel includes: using trimethylchlorosilane to perform hydrophobic modification on the aged SiO2 gel.

2. The production method according to claim 1, characterized by, The silicon source precursor is at least one of tetramethyl orthosilicate, tetraethyl orthosilicate, water glass, polysiloxane, C4H9OC2H4OH, C4H8OHOCH2OH, C2H4NO2Si(OCH3)3, and C6H 11 N2Si(OCH2COOH).

3. The preparation method according to claim 1, characterized in that, The preparation of the SiO2 gel includes: adding ammonia water to the SiO2 sol, adjusting the pH of the solution to neutral or weakly alkaline conditions, and reacting at room temperature to obtain the SiO2 gel.

4. The method of claim 1, wherein, The vacuum drying process of the SiO2 gel includes: heat-treating the SiO2 gel under vacuum at 80-100℃ for 6-8 hours.

5. The preparation method according to claim 1, characterized in that, The water is surface water or ground water, salinity<10000 mg / L.

6. A steam injection heating aerogel nanoparticle stabilized foam profile control system, comprising the aerogel nanoparticles as described in any one of claims 1-5.

7. The foam profile control system of claim 6, wherein, The steam injection heating aerogel nanoparticle stabilized foam profile control system comprises the following components by weight: 0.5-1 parts foaming agent, 0.3-0.7 parts aerogel nanoparticles, and 100 parts water.

8. The foam profile control system of claim 7, wherein, The foaming agent is a high-temperature resistant surfactant with long-chain alkyl groups, and its temperature resistance is >250℃.

9. A method for preparing a steam injection heat aerogel nanoparticle stabilized foam profile control system as described in any one of claims 6-8, comprising the following steps: Step 1: Heat-treat the aerogel nanoparticles; Step 2: Disperse the heat-treated aerogel nanoparticles in anhydrous ethanol, add water, stir, ultrasonically disperse, and centrifuge to separate the solid phase; Step 3: Add the solid phase to water, then add a foaming agent to obtain a mixture. Stir to form foam, or inject the mixture and gas into a foam generator.

10. The method of claim 9, wherein, The heat treatment temperature in step 1 is 200-250℃, and the heat treatment time is 1-2 hours.

11. The preparation method according to claim 9, characterized in that, In step 2, the amount of anhydrous ethanol added is 10-15 ml / g, and the ultrasonic dispersion time is 8-10 min.

12. The method of claim 9, wherein, In step 3, the mass concentration of aerogel nanoparticles in the mixture is 0.3-0.7%, and the mass concentration of foaming agent is 0.5-1%.

13. The method of any one of claims 9-12, wherein, The stirring described in step 3 is performed using the Waring Blender method, with a stirring speed of 6000-8000 rpm and a stirring time of 5 minutes. The gas mentioned in step 3 is nitrogen, carbon dioxide, or flue gas, and the ratio of the liquid mixture to the gas is 1:2 to 1:4.

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