Three-phase foam channeling sealing system as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oilfield chemistry, and discloses a three-phase foam channeling sealing system as well as a preparation method and application thereof. The three-phase foam channeling sealing system contains modified asphalt particle dispersion liquid and gas, the modified asphalt particle dispersion liquid contains 0.5 to 1 weight percent of modified asphalt particles and 0.075 to 0.15 weight percent of a foaming agent. According to the three-phase foam channeling sealing system, the modified asphalt particles serve as a foam stabilizer, the thickness and strength of a foam liquid film are increased, the foaming efficiency of foam is improved, the half-life period of the foam is prolonged, and therefore the effect of a foam system in an oil reservoir is enhanced; in addition, by means of the oil washing capacity of the foaming agent, the plugging capacity of the foam stabilizer and the synergistic effect of oil washing and water control, the recovery rate of the oil reservoir can be remarkably increased.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry, and in particular to a three-phase foam sealing system and a preparation method and application thereof. Background Art

[0002] Improving reservoir recovery is a key goal in oilfield development. As most oilfield development enters the middle and late stages, traditional water flooding technology faces many difficulties and challenges. Water injection causes the water content of the reservoir to rise rapidly, leading to problems such as low water flooding efficiency and difficulty in mobilizing the remaining oil. In recent years, in order to overcome these difficulties and challenges, foam flooding technology has received widespread attention as an effective measure to block high-permeability channels, regulate fluid flow paths, reduce water phase permeability, and has the characteristics of defoaming when encountering oil and reducing oil-water interfacial tension.

[0003] At present, foam flooding technology has shown good application effects under complex conditions such as high water content, heterogeneous and high permeability reservoirs. The commonly used foam flooding systems in oil fields mainly include surfactant foam system, polymer enhanced foam system, carbon dioxide (CO) foam system and nitrogen (N) foam system. Surfactant foam system is the most common foam flooding system. By adding an appropriate amount of surfactant to the injected water, a stable foam structure can be formed. The main problem of this system is that the stability of the foam is easily affected by reservoir conditions (such as temperature, salinity, etc.). In a high temperature and high salt environment, the surfactant may fail, causing the foam to dissipate quickly; the polymer enhanced foam system combines high molecular polymers with surfactants to enhance the viscosity and stability of the foam. Although polymers can improve the stability of foam, their effect in high temperature, high salt or high shear force environments is still limited. Polymers may degrade or shear thinning, resulting in a decrease in the viscosity of the foam; the CO foam system uses foam generated by CO gas and surfactants to flood oil. The CO foam system is easily dissolved in the reservoir, resulting in reduced foam stability. At the same time, the injection cost of CO is also high. The nitrogen foam system generates foam by combining nitrogen and surfactants. The initial generation of foam is difficult. In low-permeability reservoirs, the propagation range of nitrogen foam may be limited, making it difficult to achieve an ideal coverage effect.

[0004] Traditional foam flooding technology still has some problems and limitations in practical applications, such as insufficient foam stability, which cannot effectively increase the swept area; poor adaptability in high temperature and high salt environments, which makes it difficult to use in harsh reservoir conditions; and high costs for agents such as foaming agents and foam stabilizers. These problems limit the application of foam flooding technology in a wider range of reservoir conditions. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of the prior art, such as insufficient foam stability, inability to effectively increase the swept area, poor adaptability in high-temperature and high-salt environments, and difficulty in use under harsh reservoir conditions. A three-phase foam sealing system and its preparation method and application are provided. The three-phase foam sealing system provided by the present invention uses modified asphalt particles as a foam stabilizer to increase the thickness and strength of the foam liquid film, improve the foaming efficiency of the foam, and extend the half-life of the foam, thereby enhancing the effect of the foam system in the reservoir; in addition, the oil washing ability of the foaming agent and the plugging ability of the foam stabilizer, as well as the synergistic effect of oil washing and water control, can significantly improve the recovery rate of the reservoir.

[0006] In order to achieve the above-mentioned object, the present invention provides a three-phase foam sealing system on the one hand, which contains a modified asphalt particle dispersion and a gas;

[0007] The modified asphalt particle dispersion contains 0.5-1 wt% of modified asphalt particles and 0.075-0.15 wt% of a foaming agent;

[0008] The preparation method of the modified asphalt particles comprises:

[0009] (1) subjecting asphalt particles to a first contact reaction with an acid to obtain a first product system;

[0010] (2) subjecting the first product system to a second contact reaction with an oxidant to obtain a second product system, and separating and treating the second product system to obtain oxidized asphalt particles;

[0011] (3) melt-blending the oxidized asphalt particles and a modifier to obtain modified asphalt particles;

[0012] Wherein, the modifier is polyvinyl pyrrolidone.

[0013] Preferably, the modified asphalt particle dispersion further contains a balance of water.

[0014] Preferably, the foaming agent is sodium fatty acid methyl ester sulfonate and / or sodium alkylbenzene sulfonate.

[0015] Preferably, the structure of the sodium fatty acid methyl ester sulfonate is as shown in formula (1):

[0016]

[0017] R 1 It is a C14-16 alkyl group.

[0018] Preferably, the structure of the sodium alkylbenzene sulfonate is as shown in formula (2):

[0019]

[0020] R 2 It is a C10-15 alkyl group.

[0021] Preferably, the gas is air.

[0022] Preferably, in step (1), the particle size D50 of the asphalt particles is 75-125 μm;

[0023] Preferably, the softening point of the asphalt particles is 120-280°C, preferably 150-160°C.

[0024] Preferably, the acid is selected from concentrated sulfuric acid and / or concentrated nitric acid, preferably concentrated sulfuric acid.

[0025] Preferably, the weight ratio of asphalt particles: acid is 1:(10-40).

[0026] Preferably, the conditions of the first contact reaction include: reaction temperature of -5 to 5°C, and reaction time of 45-60 min.

[0027] Preferably, in step (2), the oxidant is selected from at least one of potassium permanganate, potassium dichromate and tert-butyl hydroperoxide, preferably potassium permanganate.

[0028] Preferably, the weight ratio of the asphalt particles:oxidant is 1:(1-3).

[0029] Preferably, the conditions of the second contact reaction include: first reacting at a temperature of -5 to 10°C for 2-2.5 hours, then heating up and reacting at a temperature of 40-45°C for 0.5-1 hour.

[0030] Preferably, in step (3), the weight ratio of the oxidized asphalt particles:modifier is 1:(0.1-0.3).

[0031] Preferably, the melt blending temperature is 150-180°C.

[0032] The second aspect of the present invention provides a method for preparing the above-mentioned three-phase foam sealing system, which comprises the following steps:

[0033] S1. Preparation of modified asphalt particle dispersion:

[0034] S11, mixing the modified asphalt particles, the foaming agent and water, and then shearing;

[0035] S12. Optionally, diluting the product obtained in step S11;

[0036] S2. Preparation of a three-phase foam sealing system: contacting the gas with the modified asphalt particle dispersion obtained in step S1, and then stirring to generate foam.

[0037] Preferably, in step S11, the shearing conditions include: a shearing frequency of 30-40 Hz, and a shearing time of 20-30 min.

[0038] and / or, in step S1, the particle size D50 of the modified asphalt particles in the modified asphalt particle dispersion is 5-15 μm;

[0039] And / or, in step S2, the stirring and foaming conditions include: a rotation speed of 7000-9000 rpm and a time of 2-5 min.

[0040] The third aspect of the present invention provides an application of the above-mentioned three-phase foam sealing system and the three-phase foam sealing system prepared by the above-mentioned method in sealing a high permeability layer of an oil reservoir.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects:

[0042] (1) The three-phase foam sealing system provided by the present invention uses specific modified asphalt particles as a foam stabilizer, and the foam stabilizer has a good foaming and foam stabilizing synergistic effect with the foaming agent. After adding the modified asphalt particles to the three-phase foam sealing system, the thickness and strength of the foam liquid film are increased, the foaming efficiency is improved, and the foam half-life is extended, thereby significantly improving the stability of the foam. Preferably, sodium methyl ester sulfonate (MES) and / or sodium alkylbenzene sulfonate (LAS) are used as the foaming agent, which can further improve the synergistic effect of foaming and foam stabilization.

[0043] (2) The three-phase foam sealing system provided by the present invention can effectively block the high permeability layer by using the Jamin effect before defoaming, increase the swept volume of the injected water, improve the oil washing efficiency, and thus improve the recovery rate; after defoaming, the modified asphalt particles can penetrate into the reservoir and further block the high permeability layer of the oil reservoir by using their own direct blocking, bridging blocking, or softening, deformation, and adhesion blocking at high temperature. These mechanisms increase the effective period of the sealing of the injected foam system.

[0044] (3) The modified asphalt particles used in the three-phase foam sealing system provided by the present invention have the characteristics of high temperature resistance and high salt resistance, and can be stably dispersed in the liquid phase for a long time, thereby effectively improving the stability of the three-phase foam in extreme environments. Preferably, sodium methyl ester sulfonate (MES) and / or sodium alkylbenzene sulfonate (LAS) are used as foaming agents in the present invention, which have good temperature and salt resistance and expand the scope of application of the three-phase foam system; in addition, these two surfactants have excellent interfacial activity, thereby significantly improving the oil washing efficiency while expanding the water drive swept volume.

[0045] (4) The preparation method of the modified asphalt granule three-phase foam sealing system provided by the present invention is simple and easy to operate, and the required foaming agent is low in cost and easy to obtain, and the modified asphalt granules also have a low cost. The preparation process of this system is simple and suitable for large-scale application on site, showing good economic benefits and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a microscope image of the foam shape of the three-phase foam sealing system prepared in Comparative Example 1.

[0047] Figure 2 This is a microscope image of the foam shape of the three-phase foam sealing system prepared in Example 1. DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0049] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0050] The three-phase foam sealing system provided by the invention contains a modified asphalt particle dispersion and gas, wherein the modified asphalt particle dispersion contains 0.5-1% by weight of modified asphalt particles and 0.075-0.15% by weight of a foaming agent.

[0051] In a preferred embodiment, the modified asphalt particle dispersion also contains a residual amount of water, that is, the modified asphalt particle dispersion contains only water in addition to the modified asphalt particles and the foaming agent. The water in the modified asphalt particle dispersion can be clean water and / or formation water.

[0052] In a preferred embodiment, the particle size D50 of the modified asphalt particles in the three-phase foam sealing system can be 5-15 μm, which can ensure that the modified asphalt particles are injected into the formation while enhancing the foam. In the present invention, the particle size D50 of the asphalt particles refers to the median particle size D50, which can be measured by a laser particle size tester.

[0053] In the present invention, the amount of the modified asphalt particle dispersion and the gas is not limited, as long as a foam system can be formed. In the process of preparing the three-phase foam sealing system, the role of the gas is to serve as a gas source so that the modified asphalt particle dispersion is stirred and foamed. In the present invention, the gas can be a conventional choice in the art. In a preferred embodiment, the gas is air.

[0054] In a preferred embodiment, the modified asphalt particles are prepared by a specific method. Specifically, the preparation method of the modified asphalt particles includes:

[0055] (1) subjecting asphalt particles to a first contact reaction with an acid to obtain a first product system;

[0056] (2) subjecting the first product system to a second contact reaction with an oxidant to obtain a second product system, and separating and treating the second product system to obtain oxidized asphalt particles;

[0057] (3) melt-blending the oxidized asphalt particles and a modifier to obtain modified asphalt particles;

[0058] Wherein, the modifier is polyvinyl pyrrolidone.

[0059] In the present invention, on the one hand, the modified asphalt particles prepared by the preferred method have the characteristics of high temperature resistance and high salt resistance, and can be stably dispersed in the liquid phase for a long time, thereby effectively improving the stability of the three-phase foam in extreme environments; on the other hand, the modified asphalt particles prepared by the preferred method are used as a foam stabilizer, and the foam stabilizer and the foaming agent have good foaming and foam stabilization synergistic effects. After the modified asphalt particles are added to the three-phase foam sealing system, the thickness and strength of the foam liquid film are increased, the foaming efficiency is improved, and the foam half-life is prolonged, thereby significantly improving the stability of the foam.

[0060] In the present invention, the asphalt particles are broadly defined, and the asphalt raw materials commonly used in the preparation of asphalt plugging materials in the art can be used. Preferably, in step (1), the particle size D50 of the asphalt particles is 75-125 μm, which can well match the plugging pore size of the target reservoir.

[0061] In some embodiments, the softening point of the asphalt particles is 120-280°C, preferably 150-160°C.

[0062] In the method for preparing modified asphalt particles, in step (1), the acid can be selected from concentrated sulfuric acid and / or concentrated nitric acid, preferably concentrated sulfuric acid. Preferably, the acid is concentrated sulfuric acid with a concentration of 98% by weight.

[0063] In the preparation method of the modified asphalt particles, preferably, in step (1), the weight ratio of the asphalt particles: acid can be 1: (10-40). By contacting the asphalt particles with the acid for oxidation reaction, the smooth morphology of the asphalt particle surface can be destroyed, the surface roughness of the asphalt particles can be increased, the wrinkles can be increased to increase the reaction sites, and the asphalt particles can be placed in a liquid environment, which is beneficial to the reaction of subsequent steps.

[0064] In the present invention, the conditions of the first contact reaction include: a reaction temperature of -5 to 5°C, and a reaction time of 45 to 60 minutes. Preferably, the first contact reaction is carried out under stirring.

[0065] According to the present invention, in the method for preparing modified asphalt particles, in step (2), the oxidant can be selected from at least one of potassium permanganate, potassium dichromate and tert-butyl hydroperoxide, preferably potassium permanganate.

[0066] In the preparation method of the modified asphalt particles, in step (2), the weight ratio of the asphalt particles: the oxidant can be 1: (1-3). By contacting the first product system with the oxidant for reaction, oxygen-containing groups such as hydroxyl groups and epoxy groups can be combined with carbon atoms in the asphalt particles, thereby grafting hydrophilic groups onto the asphalt particles, thereby making the asphalt particles have certain hydrophilic properties.

[0067] In the present invention, the conditions of the second contact reaction include: first reacting at a temperature of -5 to 10° C. for 2-2.5 hours, then heating and reacting at a temperature of 40-45° C. for 0.5-1 hour. Preferably, the second contact reaction is carried out under stirring.

[0068] In the present invention, the oxidant is fed slowly and evenly, and the feeding time is not less than 10 minutes, and more preferably the feeding time is 15-20 minutes, which is conducive to the safe reaction.

[0069] In the method for preparing modified asphalt particles, in step (2), the separation treatment includes product dilution, reduction of residual oxidant, centrifugal washing and drying performed in sequence.

[0070] In the present invention, the second product system may be diluted before the second product system is separated. For the dilution of the second product system, water may be added to the second product system and stirred for dilution. Preferably, the first part of water (the amount added is the same as the total weight of the raw asphalt particles, acid and oxidant) is slowly added to the second product system, and then the system temperature is raised to 90-95°C, and then the second part of water (the amount added is preferably 1.5 times the weight of the first part of water) is added and stirred evenly. According to the present invention, for the reduction of residual oxidants, a hydrogen peroxide solution may be added to the system after the product dilution to reduce the residual oxidants in the system.

[0071] In the present invention, for the centrifugal washing, the system obtained after reducing the residual oxidant can be first centrifuged, and then the solid product obtained by centrifugation can be washed with water. After washing, the solid can be centrifuged again, and the washing and centrifugation can be repeated multiple times until the pH value of the centrifuge reaches 5-6, so that the residual acid is cleaned.

[0072] In the method for preparing the modified asphalt particles, in step (3), the oxidized asphalt particles are melt-blended with a modifier, which can further improve the hydrophilicity of the oxidized asphalt particles. Preferably, the modifier is polyvinyl pyrrolidone.

[0073] In the method for preparing the modified asphalt particles, in step (3), the weight ratio of the oxidized asphalt particles:modifier is 1:(0.1-0.3), preferably 1:(0.2-0.25).

[0074] In the present invention, the melt blending is preferably carried out in a twin-screw extruder, and preferably, the temperature of the melt blending is 150-180°C, preferably 155-165°C.

[0075] In a more preferred embodiment, the preparation method of the modified asphalt particles comprises: (1) subjecting the asphalt particles to a first contact reaction with concentrated sulfuric acid (the weight ratio of asphalt particles to concentrated sulfuric acid is 1:20-25; the reaction temperature of the first contact reaction is 0-5°C, and the reaction time is 50-60 min) to obtain a first product system; (2) subjecting the first product system to a second contact reaction with potassium permanganate (the weight ratio of asphalt particles to potassium permanganate is 1:2-3; the second contact reaction is first reacted at a temperature of 0-5°C for 2-2.5 h, then heated and reacted at a temperature of 40-45°C for 0.5-1 h) to obtain a second product system, and separating the second product system to obtain oxidized asphalt particles; (3) melt blending the oxidized asphalt particles with polyvinyl pyrrolidone (the weight ratio of oxidized asphalt particles to polyvinyl pyrrolidone is 1:0.2-0.25; the temperature of the melt blending is 155-165°C) to obtain modified asphalt particles.

[0076] In the present invention, the foaming agent can be a conventional choice in the art, as long as it has a foaming effect. In a preferred embodiment, the foaming agent is sodium methyl ester sulfonate of fatty acid and / or sodium alkylbenzene sulfonate. Using sodium methyl ester sulfonate of fatty acid (MES) and / or sodium alkylbenzene sulfonate (LAS) as a foaming agent can further improve the synergistic effect of foaming and foam stabilization; and using sodium methyl ester sulfonate of fatty acid (MES) and / or sodium alkylbenzene sulfonate (LAS) as a foaming agent has good temperature and salt resistance, which expands the scope of application of the three-phase foam system; in addition, these two surfactants have excellent interfacial activity, thereby significantly improving the oil washing efficiency while expanding the swept volume of water drive.

[0077] In some more preferred embodiments, the structure of the sodium fatty acid methyl ester sulfonate is shown in formula (1):

[0078] Among them, R 1 It is a C14-16 alkyl group.

[0079] In some other more preferred embodiments, the structure of the sodium alkylbenzene sulfonate is shown in formula (2):

[0080] Among them, R 2 It is a C10-15 alkyl group.

[0081] The three-phase foam sealing system provided by the present invention adopts specific modified asphalt particles as a foam stabilizer, and the foam stabilizer and the foaming agent have good foaming and foam stabilizing synergistic effects. After the modified asphalt particles are added to the three-phase foam sealing system, the thickness and strength of the foam liquid film are increased, the foaming efficiency is improved, and the foam half-life is extended, thereby significantly improving the stability of the foam. Before defoaming, the foam sealing system can effectively block the high permeability layer by using the Jamin effect, increase the swept volume of the injected water, improve the oil washing efficiency, and thus improve the recovery rate; after defoaming, the modified asphalt particles can penetrate into the reservoir, and further block the high permeability layer of the oil reservoir by using their own direct blocking, bridging blocking, or softening, deformation, and adhesion blocking at high temperature. These mechanisms increase the effective period of the sealing of the injection foam system. The modified asphalt particles used in the three-phase foam sealing system provided by the present invention have the characteristics of high temperature resistance and high salt resistance, and can be stably dispersed in the liquid phase for a long time, thereby effectively improving the stability of the three-phase foam in extreme environments. The present invention utilizes the oil washing ability of the foaming agent and the plugging ability of the foam stabilizer, as well as the synergistic effect of oil washing and water control, and can significantly improve the recovery rate of the oil reservoir.

[0082] The method for preparing the aforementioned three-phase foam sealing system provided by the present invention comprises the following steps:

[0083] S1. Preparation of modified asphalt particle dispersion:

[0084] S11, mixing the modified asphalt particles, the foaming agent and water, and then shearing;

[0085] S12. Optionally, diluting the product obtained in step S11;

[0086] S2. Preparation of a three-phase foam sealing system: contacting the gas with the modified asphalt particle dispersion obtained in step S1, and then stirring to generate foam.

[0087] The preparation method of the modified asphalt particle three-phase foam sealing system of the present invention is relatively simple to operate. First, the modified asphalt particles, the foaming agent and water are mixed, and then sheared. Then, the gas is contacted with the obtained modified asphalt particle dispersion and stirred to foam.

[0088] In the method described in the present invention, in step S1, a high-concentration modified asphalt particle dispersion mother liquor can be first prepared and then diluted with water to obtain a modified asphalt particle dispersion containing 0.5-1% by weight of modified asphalt particles and 0.075-0.15% by weight of a foaming agent, that is, step S1 includes two steps, step S11 and step S12; or a modified asphalt particle dispersion containing 0.5-1% by weight of modified asphalt particles and 0.075-0.15% by weight of a foaming agent can be directly obtained, that is, step S1 only includes step S11.

[0089] In a preferred embodiment, the preparation process of the modified asphalt particle dispersion in step S1 includes:

[0090] S11, mixing the modified asphalt particles, the foaming agent and water, and then shearing to obtain a high-concentration modified asphalt particle dispersion mother liquor containing 15-40 wt % of the modified asphalt particles and 2-5 wt % of the foaming agent;

[0091] S12. Dilute the product obtained in step S11 with water to obtain a modified asphalt particle dispersion containing 0.5-1 wt % of modified asphalt particles and 0.075-0.15 wt % of a foaming agent.

[0092] In the present invention, the process of step S11 includes: adding modified asphalt particles and a foaming agent into water at room temperature, stirring for 5-10 minutes, and then placing the obtained mixture in a colloid mill for shearing.

[0093] In some embodiments, in step S11, the shearing conditions include: a shearing frequency of 30-40 Hz, and a shearing time of 20-30 min.

[0094] In a preferred embodiment, the particle size D50 of the modified asphalt particles in the modified asphalt particle dispersion obtained in step S1 can be 5-15 μm, which can ensure that the modified asphalt particles can be injected into the formation while enhancing the foam.

[0095] In step S2, the amount of the gas and the modified asphalt particle dispersion is not limited, as long as the gas as a gas source is in contact with the modified asphalt particle dispersion to stir and foam. In a preferred embodiment, step S2 adopts a Waring Blender method for stirring and foaming. In a more preferred embodiment, the stirring and foaming conditions include: a rotation speed of 7000-9000rpm and a time of 2-5min.

[0096] The three-phase foam sealing system prepared by the method described in the present invention has all the advantages of the three-phase foam sealing system described above.

[0097] The present invention also provides the above-mentioned three-phase foam sealing system and the use of the three-phase foam sealing system prepared by the above-mentioned method in sealing a high permeability layer of an oil reservoir.

[0098] The following examples further illustrate the three-phase foam sealing system and its preparation method and application. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.

[0099] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0100] In the following preparation examples and embodiments,

[0101] Asphalt particles: particle size (D50) is 100 μm, ash content ≤ 0.5%, sulfur content ≤ 0.4%, softening point is 160°C, purchased from Hebei Joyson New Materials Technology Co., Ltd.

[0102] The structural formula of sodium methyl ester sulfonate (MES) is R 1 CH(SO 3 Na)COOCH 3 , R1 is a C14-16 alkyl group, and the CAS number is 93348-22-2.

[0103] The structural formula of sodium alkylbenzene sulfonate (LAS) is R 2 -C 6 H 4 -SO 3 Na, R 2 It is a C12 alkyl group (average), with CAS numbers of 2211-98-5 and 25155-30-0.

[0104] In the following examples and comparative examples:

[0105] The Waring Blender method was used to determine the foam volume and half-life. The specific process is as follows:

[0106] Add the test solution into the measuring cup, stir at a constant speed for 60 seconds and then stop stirring. Record the generated foam volume V0 to measure the foaming ability of the solution. This is the method for measuring the foam (bubble) volume.

[0107] As time goes by, liquid continues to precipitate from the foam. The time τ(s) required for half of the liquid to be discharged from the foam is recorded to measure the stability of the foam. This is the method for testing the half-life.

[0108] The preparation example is used to illustrate the preparation process of modified asphalt particles.

[0109] Preparation Example

[0110] The preparation method of the modified asphalt particles comprises:

[0111] (1) adding asphalt particles to concentrated sulfuric acid (concentration of 98 wt%), and performing a first contact reaction under stirring conditions (reaction temperature of 0° C., reaction time of 60 min) to obtain a first product system; wherein the weight ratio of asphalt particles to concentrated sulfuric acid is 1:25;

[0112] (2) Under stirring conditions, potassium permanganate (the weight ratio of asphalt particles to potassium permanganate is 1:2) is slowly added to the first product system for 20 minutes, followed by a second contact reaction (first reacting at 0°C for 2 hours, then heating to 40°C and reacting at this temperature for 1 hour) to obtain a second product system;

[0113] Slowly add the first part of water to the above-mentioned second product system for dilution (the amount added is the same as the total weight of the raw asphalt particles, concentrated sulfuric acid and potassium permanganate), stir for 30 minutes, then raise the system temperature to 90°C, add the second part of water (the amount added is 1.5 times the weight of the first part of water), and stir for 30 minutes; add hydrogen peroxide solution to the diluted system until no bubbles are generated to completely reduce the residual potassium permanganate in the system; then centrifuge the system (the centrifuge speed is 10,000 rpm, and the centrifugation time is 30 minutes). After the centrifugation is completed, pour out the upper clear liquid, retain the solid product, wash the solid product with water, and then centrifuge again to separate the solid after washing. Repeat the above centrifugation and washing until the pH value of the centrifuge reaches 6, so that the residual acid is cleaned, and then dry to obtain oxidized asphalt particles;

[0114] (3) The oxidized asphalt particles and polyvinylpyrrolidone are melt-blended in a twin-screw extruder (the weight ratio of oxidized asphalt particles to polyvinylpyrrolidone is 1:0.25, and the melt-blending temperature is 160° C.) to obtain modified asphalt particles.

[0115] Example 1

[0116] S1. Preparation of modified asphalt particle dispersion:

[0117] S11. At room temperature, add 150 g of modified asphalt particles and 22.5 g of sodium methyl ester sulfonate (MES) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 40 Hz for 30 minutes to obtain a mother liquor of modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles is 30%, and the mass fraction of sodium methyl ester sulfonate is 4.5%;

[0118] S12. At room temperature, 3.33 g of the mother liquor of the modified asphalt particle dispersion was added to 96.67 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 1%, the particle size D50 of the modified asphalt particles was 5 μm, and the mass fraction of sodium fatty acid methyl ester sulfonate was 0.15%;

[0119] S2. Preparation of three-phase foam sealing system:

[0120] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a three-phase foam sealing system P1. The bubble volume of the three-phase foam sealing system was measured to be 325 mL and the foam half-life was 64 min.

[0121] The microscopic image of the foam shape of the three-phase foam sealing system prepared in this example is as follows: Figure 2 As shown. Figure 2 It can be seen that compared with Comparative Example 1, the foam size of the three-phase foam sealing system is uniform, the foam is denser, more foam and larger foam volume can be produced. The foam wall thickness is thicker, which can increase the stability of the foam and extend the half-life of the foam.

[0122] Example 2

[0123] S1. Preparation of modified asphalt particle dispersion:

[0124] S11. At room temperature, add 150 g of modified asphalt particles and 22.5 g of sodium methyl ester sulfonate (MES) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 30 Hz for 20 minutes to obtain a mother liquor of modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles is 30%, and the mass fraction of sodium methyl ester sulfonate is 4.5%;

[0125] S12. At room temperature, 3.33 g of the mother liquor of the modified asphalt particle dispersion was added to 96.67 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 1%, the particle size D50 of the modified asphalt particles was 15 μm, and the mass fraction of sodium fatty acid methyl ester sulfonate was 0.15%;

[0126] S2. Preparation of three-phase foam sealing system:

[0127] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a three-phase foam sealing system P2. The bubble volume of the three-phase foam sealing system was measured to be 315 mL and the foam half-life was 60 min.

[0128] Example 3

[0129] S1. Preparation of modified asphalt particle dispersion:

[0130] S11. At room temperature, add 150 g of modified asphalt particles and 22.5 g of sodium alkylbenzene sulfonate (LAS) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 40 Hz for 30 minutes to obtain a mother liquor of modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles is 30%, and the mass fraction of the sodium alkylbenzene sulfonate is 4.5%;

[0131] S12. At room temperature, 3.33 g of the mother liquor of the modified asphalt particle dispersion was added to 96.67 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 1%, the particle size D50 of the modified asphalt particles was 5 μm, and the mass fraction of sodium alkylbenzene sulfonate was 0.15%;

[0132] S2. Preparation of three-phase foam sealing system:

[0133] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 9000 rpm and the stirring time was 5 minutes to obtain a three-phase foam sealing system P3. The bubble volume of the modified asphalt particle three-phase foam sealing system was measured to be 375 mL and the foam half-life was 73 minutes.

[0134] Example 4

[0135] S1. Preparation of modified asphalt particle dispersion:

[0136] S11. At room temperature, add 150 g of modified asphalt particles and 22.5 g of sodium alkylbenzene sulfonate (LAS) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 30 Hz for 20 minutes to obtain a mother liquor of modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles is 30%, and the mass fraction of the sodium alkylbenzene sulfonate is 4.5%;

[0137] S12. At room temperature, 3.33 g of the mother liquor of the modified asphalt particle dispersion was added to 96.67 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 1%, the particle size D50 of the modified asphalt particles was 15 μm, and the mass fraction of sodium alkylbenzene sulfonate was 0.15%;

[0138] S2. Preparation of three-phase foam sealing system:

[0139] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a three-phase foam sealing system P4. The bubble volume of the modified asphalt particle three-phase foam sealing system was measured to be 350 mL and the foam half-life was 68 min.

[0140] Example 5

[0141] S1. Preparation of modified asphalt particle dispersion:

[0142] S11. At room temperature, add 150 g of modified asphalt particles, 11.25 g of sodium methyl ester sulfonate (MES) and 11.25 g of sodium alkylbenzene sulfonate (LAS) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 40 Hz for 30 minutes to obtain a modified asphalt particle dispersion mother liquor, wherein the mass fraction of the modified asphalt particles is 30%, the mass fraction of sodium methyl ester sulfonate is 2.25%, and the mass fraction of sodium alkylbenzene sulfonate is 2.25%;

[0143] S12. At room temperature, 3.33 g of the mother liquor of the modified asphalt particle dispersion was added to 96.67 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 1%, the particle size D50 of the modified asphalt particles was 5 μm, the mass fraction of sodium fatty acid methyl ester sulfonate was 0.075%, and the mass fraction of sodium alkylbenzene sulfonate was 0.075%;

[0144] S2. Preparation of three-phase foam sealing system:

[0145] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a three-phase foam sealing system P5. The bubble volume of the three-phase foam sealing system was measured to be 395 mL and the foam half-life was 78 min.

[0146] Example 6

[0147] The method of Example 1 was followed, except that the sodium fatty acid methyl ester sulfonate in Example 1 was replaced by sodium α-olefin sulfonate to obtain a three-phase foam sealing system P6. The bubble volume of the three-phase foam sealing system was measured to be 315 mL, and the foam half-life was 53 min.

[0148] Comparative Example 1

[0149] The method of Example 1 is followed, except that no modified asphalt particles are added.

[0150] The specific operations are:

[0151] At room temperature, 22.5 g of sodium fatty acid methyl ester sulfonate (MES) was added to 327.5 g of deionized water, and the mixture was stirred for 10 minutes. Then, the obtained mixture was sheared and ground using a colloid mill at a shear frequency of 40 Hz for 30 minutes to obtain a dispersion mother liquor, wherein the mass fraction of sodium fatty acid methyl ester sulfonate was 4.5%;

[0152] At room temperature, 3.33 g of the mother solution was added to 96.67 g of deionized water and stirred for 5 min to prepare a dispersion, wherein the mass fraction of sodium fatty acid methyl ester sulfonate was 0.15%;

[0153] S2. Preparation of three-phase foam sealing system:

[0154] The air was brought into contact with the dispersion and stirred and foamed by the Waring Blender method. During the stirring process of the dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a foam sealing system DP1. The bubble volume of the foam sealing system was measured to be 285 mL and the foam half-life was 40 min.

[0155] The microscopic image of the foam shape of the three-phase foam sealing system prepared in this comparative example 1 is as follows Figure 1 As shown. Figure 1 It can be seen that, compared with Example 1, the foam size of the three-phase foam sealing system is uneven and the foam wall thickness is thinner.

[0156] Comparative Example 2

[0157] The method of Example 1 is followed, except that the modified asphalt particle dispersion contains 3 wt% of modified asphalt particles.

[0158] The specific operations are:

[0159] S1. Preparation of modified asphalt particle dispersion:

[0160] S11. At room temperature, add 150 g of modified asphalt particles and 22.5 g of sodium methyl ester sulfonate (MES) to 327.5 g of deionized water, stir for 10 minutes until fully dispersed, and then use a colloid mill to shear grind the obtained mixture at a shear frequency of 40 Hz for 30 minutes to obtain a mother liquor of modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles is 30%, and the mass fraction of sodium methyl ester sulfonate is 4.5%;

[0161] S12. At room temperature, 10 g of the mother liquor of the modified asphalt particle dispersion was added to 90 g of deionized water and stirred for 5 min to prepare a modified asphalt particle dispersion, wherein the mass fraction of the modified asphalt particles was 3%, the particle size D50 of the modified asphalt particles was 5 μm, and the mass fraction of sodium fatty acid methyl ester sulfonate was 0.15%;

[0162] S2. Preparation of three-phase foam sealing system:

[0163] The air was brought into contact with the modified asphalt particle dispersion and stirred and foamed using the Waring Blender method. During the stirring process of the modified asphalt particle dispersion, the rotation speed was 7000 rpm and the stirring time was 3 min to obtain a three-phase foam sealing system DP2. The bubble volume of the three-phase foam sealing system was measured to be 300 mL and the foam half-life was 50 min.

[0164] It can be seen from the examples and comparisons that the three-phase foam sealing system prepared according to the method of the present invention has a larger bubble volume and a longer foam half-life.

[0165] Test case plugging test

[0166] 1. Foam system plugging rate

[0167] The foam sealing systems P1-P6 and DP1-DP2 prepared in the examples and comparative examples were used to carry out sealing tests, and the process is as follows.

[0168] (1) Take 8 sand-filled pipe models with similar permeability;

[0169] (2) Add 1 mL x min to the sand filling tube. -1 Inject high-temperature steam at an injection rate of 1000 rpm until the pressure stabilizes and record the pressure P. 1 ;

[0170] (3) At 20°C, 1 MPa back pressure, 1 mL × min -1 At an injection rate of 1.5 PV of the foam sealing system prepared in the embodiment and the comparative example respectively;

[0171] (4) Continue with 1 mL × min -1 Inject high-temperature steam at an injection rate of 1000 rpm until the pressure stabilizes and record the pressure P. 2 ;

[0172] (5) According to the formula The steam phase plugging rate was calculated and the results are shown in Table 1.

[0173] Table 1

[0174]

[0175]

[0176] 2. Blockage rate after defoaming

[0177] The foam sealing systems P1-P6 and DP1-DP3 prepared in the examples and comparative examples were used to carry out sealing tests, and the process is as follows.

[0178] 1. Take 8 sand-filled pipe models with similar permeability;

[0179] 2. Add 1 mL x min to the sand filling tube. -1 Inject high-temperature steam at an injection rate of 1000 rpm until the pressure stabilizes and record the pressure P. 1 ;

[0180] 2. At 20℃, 1Mpa back pressure, 1mL×min -1 At an injection rate of 1.5 PV of the foam sealing system prepared in the embodiment and the comparative example respectively;

[0181] 3. Aging at 80℃ for 12h to simulate the plugging effect after defoaming;

[0182] 4. Continue to 1mL×min -1 Inject high-temperature steam at an injection rate of 1000 rpm until the pressure stabilizes and record the pressure P. 2 ;

[0183] 5. According to the formula The steam phase plugging rate was calculated and the results are shown in Table 2.

[0184] Table 2

[0185]

[0186]

[0187] It can be seen from the table that the three-phase foam channel blocking system prepared by adopting the technical solution of the present invention has a higher blocking rate and better blocking performance.

[0188] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A three-phase foam sealing system, characterized in that: The three-phase foam sealing system contains a modified asphalt particle dispersion and a gas; The modified asphalt particle dispersion contains 0.5-1 wt% of modified asphalt particles and 0.075-0.15 wt% of a foaming agent; The preparation method of the modified asphalt particles comprises: (1) subjecting asphalt particles to a first contact reaction with an acid to obtain a first product system; (2) subjecting the first product system to a second contact reaction with an oxidant to obtain a second product system, and separating and treating the second product system to obtain oxidized asphalt particles; (3) melt-blending the oxidized asphalt particles and a modifier to obtain modified asphalt particles; Wherein, the modifier is polyvinyl pyrrolidone.

2. The three-phase foam sealing system according to claim 1, characterized in that: The modified asphalt particle dispersion also contains a balance of water.

3. The three-phase foam sealing system according to claim 1 or 2, characterized in that: The foaming agent is sodium fatty acid methyl ester sulfonate and / or sodium alkyl benzene sulfonate; Preferably, the structure of the sodium fatty acid methyl ester sulfonate is as shown in formula (1): R1 is a C14-16 alkyl group; Preferably, the structure of the sodium alkylbenzene sulfonate is as shown in formula (2): R2 is a C10-15 alkyl group.

4. The three-phase foam sealing system according to any one of claims 1 to 3, characterized in that: The gas is air.

5. The three-phase foam sealing system according to any one of claims 1 to 4, characterized in that: In step (1), the particle size D50 of the asphalt particles is 75-125 μm; and / or, the softening point of the asphalt particles is 120-280°C, preferably 150-160°C; and / or, the acid is selected from concentrated sulfuric acid and / or concentrated nitric acid, preferably concentrated sulfuric acid; and / or, the weight ratio of the asphalt particles: acid is 1:(10-40); And / or, the conditions of the first contact reaction include: reaction temperature of -5 to 5°C, reaction time of 45-60 min.

6. The three-phase foam sealing system according to any one of claims 1 to 5, characterized in that: In step (2), the oxidant is selected from at least one of potassium permanganate, potassium dichromate and tert-butyl hydroperoxide, preferably potassium permanganate; and / or, the weight ratio of the asphalt particles:oxidant is 1:(1-3); And / or, the conditions of the second contact reaction include: first reacting at a temperature of -5 to 10°C for 2-2.5 hours, then heating and reacting at a temperature of 40-45°C for 0.5-1 hour.

7. The three-phase foam sealing system according to any one of claims 1 to 6, wherein: In step (3), the weight ratio of the oxidized asphalt particles to the modifier is 1:(0.1-0.3); And / or, the temperature of the melt blending is 150-180°C.

8. A method for preparing the three-phase foam sealing system according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. Preparation of modified asphalt particle dispersion: S11, mixing the modified asphalt particles, the foaming agent and water, and then shearing; S12. Optionally, diluting the product obtained in step S11; S2. Preparation of a three-phase foam sealing system: contacting the gas with the modified asphalt particle dispersion obtained in step S1, and then stirring to generate foam.

9. The method according to claim 8, characterized in that In step S11, the shearing conditions include: a shearing frequency of 30-40 Hz and a shearing time of 20-30 min; and / or, in step S1, the particle size D50 of the modified asphalt particles in the modified asphalt particle dispersion is 5-15 μm; And / or, in step S2, the stirring and foaming conditions include: a rotation speed of 7000-9000 rpm and a time of 2-5 min.

10. Use of the three-phase foam sealing system according to any one of claims 1 to 7 and the three-phase foam sealing system prepared by the method according to claim 8 or 9 in plugging high permeability layers in oil reservoirs.

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