Resistance-increasing in-situ gel deep profile control agent and preparation method thereof

Abstract

The invention belongs to the technical field of oil-gas field development and recovery efficiency improvement, and particularly relates to a resistance-increasing type in-situ gel deep profile control agent and a preparation method thereof. The resistance-increasing type in-situ gel deep profile control agent is prepared from the following raw materials in percentage by weight: 3 to 8 percent of water-soluble functional monomer, 0.5 to 2 percent of functional micro-nano particles, 0.3 to 1 percent of gelling control agent and the balance of water. The profile control agent reacts in a stratum to form three-dimensional network structure gel with functional micro-nano particles as crosslinking nodes, so that the temperature resistance is greatly improved, the dehydration rate at the constant temperature of 120 DEG C for 90 days is lower than 10%, and the profile control agent can be used for deep profile control of oil reservoirs at the high temperature of 120 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development and recovery enhancement, and particularly relates to a resistance-increasing in-situ gel deep profile control agent and a preparation method thereof. Background Art

[0002] Weak gel profile control technology is a deep reservoir profile control technique developed based on bulk polymer gels and polymer flooding. The core of this technology lies in the weak gel system. This system typically consists of a low-concentration (800-3000 mg / L) polymer and a crosslinker. The gelation mechanism is as follows: under certain conditions, the polymer and crosslinker molecules interact through physical and chemical interactions (such as coordination, condensation, electrostatic attraction, and hydrophobic association), ultimately forming an amorphous, free-flowing semifluid with a three-dimensional network structure dominated by intermolecular crosslinking, supplemented by intramolecular crosslinking. Compared to bulk polymer gels, weak gel systems exhibit superior fluidity, allowing them to migrate relatively far within the reservoir. Compared to polymer solutions, at the same polymer concentration, weak gel systems have higher viscosity, enabling them to block high-permeability channeling areas in reservoirs. Precisely due to these advantages, weak gel profile control technology has become a key technology for late-stage oilfield stabilization and water control in waterflooding development both domestically and internationally.

[0003] With the continuous expansion of mine applications, the shortcomings of the weak gel system in profile control have become increasingly prominent, mainly manifested in: (1) high requirements for the preparation water, and in high-mineralization water (mineralization ≥10×10 4 mg / L), the polymer components in the weak gel system are difficult to fully dissolve, which makes it difficult for the system to gel later, or even fail to gel. (2) The initial viscosity of the system is high, which causes the system to have a high pressure during the injection process, and even the phenomenon of not being able to inject in medium and low permeability reservoirs. (3) During the injection process, the polymer in the system is severely shear-degraded, which causes the gel strength of the system to be significantly weakened after entering the formation, and the blocking ability of the crossflow area after gelation is sharply reduced. (4) The blocking ability in high-porosity and high-permeability reservoirs with a porosity greater than 20% and a permeability greater than 1000mD is poor, which makes it very easy for the subsequent injected water to break through, and the effective period is short. Summary of the Invention

[0004] In order to overcome the above-mentioned deficiencies of the existing weak gel system for profile control, the present invention provides a resistance-increasing in-situ gel deep profile control agent and a preparation method thereof.

[0005] Specifically, the present invention is achieved through the following technical solutions:

[0006] A resistance-increasing in-situ gel deep profile control agent is prepared from raw materials comprising the following components by weight: 3-8% water-soluble functional monomer, 0.5-2% functional micro-nano particles, 0.3-1% gelation control agent and the balance water.

[0007] The above-mentioned resistance-increasing in-situ gel deep profile control agent is prepared from the following raw materials by weight percentage: 5-8% water-soluble functional monomer, 0.8-2% functional micro-nano particles, 0.4-0.8% gelation control agent and the balance water.

[0008] The above-mentioned resistance-increasing in-situ gel deep profile control agent, wherein the water-soluble functional monomer includes one or a mixture of polyethylene glycol (1000) monomethyl ether methacrylate, polyethylene glycol (2000) monomethyl ether methacrylate, polyethylene glycol (4000) monomethyl ether methacrylate, polyethylene glycol (6000) monomethyl ether methacrylate, polyethylene glycol (8000) monomethyl ether methacrylate, and acrylamide.

[0009] In the above-mentioned resistance-increasing in-situ gel deep profile control agent, the functional micro-nanoparticles include one or a mixture of cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface and silica gel micro-nanoparticles with carbon-carbon double bonds on the surface.

[0010] The above-mentioned resistance-increasing in-situ gel deep profile control agent and the functional micro-nano particles have a particle size distribution between 50 nm and 10 μm.

[0011] The above-mentioned resistance-increasing in-situ gel deep profile control agent, the gelation control agent includes one or a mixture of azobisisobutylimidazoline hydrochloride, azobisisopropylimidazoline, tert-butyl perbenzoate, tert-amyl hydroperoxide, and tert-butyl peroxide isopropylbenzene.

[0012] In the above-mentioned resistance-increasing in-situ gel deep profile control agent, the water is formation water or seawater.

[0013] The above-mentioned resistance-enhancing in-situ gel deep profile control agent has a maximum salinity of 30×10 4 mg / L.

[0014] A method for preparing a resistance-increasing in-situ gel deep profile control agent comprises:

[0015] (1) Add water-soluble functional monomers into water according to the ratio and stir to completely dissolve them;

[0016] (2) Add functional micro-nanoparticles according to the proportion under stirring and continue stirring until they are completely dissolved;

[0017] (3) Adding a gelling control agent according to the proportion, stirring to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0018] In the method for preparing the above-mentioned resistance-increasing in-situ gel deep profile control agent, the stirring rate in steps (1) to (3) is ≥20 rpm.

[0019] A resistance-increasing in-situ gel deep profile control agent is prepared by the above-mentioned preparation method.

[0020] The above-mentioned resistance-increasing in-situ gel deep profile control agent has an initial viscosity of 1 to 2 mPa·s, a gelling time in an oil reservoir at 50 to 120°C that is controllable between 5 and 15 days, and a dehydration rate of less than 10% at a constant temperature of 120°C for 90 days after gelling.

[0021] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0022] (1) The functional monomers, functional micro-nano particles and gelation control agents used in the resistance-enhancing in-situ gel deep profile control agent of the present invention all have good salt resistance, even when the mineralization degree is 30×10 4 mg / L high-mineralization water, it can be well dissolved and dispersed. Therefore, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention can be prepared using high-mineralization formation water or seawater, which can significantly reduce the cost of liquid preparation;

[0023] (2) Compared with the polymers in the weak gel system, the functional monomer has a small molecular weight. Therefore, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention has the advantages of low initial viscosity and easy injection;

[0024] (3) Since the functional monomer has a small molecular weight and the functional micro-nano particles have a rigid structure, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention is not affected by shear degradation during the injection process;

[0025] (4) The profile control agent is injected into the formation and reacts in the formation to form a three-dimensional network structure gel with functional micro-nanoparticles as cross-linking nodes. Therefore, compared with the existing weak gel profile control system, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention has a higher plugging strength for high-permeability crossflow areas, is not easy to be broken through by subsequent injection of water, and has a long-lasting plugging effect;

[0026] (5) The time it takes for the profile control agent to react and form gel in a formation with a temperature of 50-120°C can be flexibly adjusted within the range of 5-15 days by adjusting the amount and combination of the gel control agent. Therefore, deep profile control operations with large liquid volumes and long well spacing can be carried out.

[0027] (6) Since the profile control agent reacts in the formation to form a three-dimensional network structure gel with functional micro-nano particles as cross-linking nodes, the temperature resistance is greatly improved. The dehydration rate is less than 10% at a constant temperature of 120°C for 90 days, and it can be used for deep profile control in high-temperature oil reservoirs at 120°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those skilled in the art by reading the following detailed description of the preferred embodiment.The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0029] Figure 1 These are photos of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 1 of the present invention before and after gelation;

[0030] Figure 2 This is a scanning electron microscope photograph of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 1 of the present invention after gelation;

[0031] Figure 3 These are photos of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 2 of the present invention before and after gelation;

[0032] Figure 4 This is a scanning electron microscope photograph of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 2 of the present invention after gelation;

[0033] Figure 5 These are photos of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 3 of the present invention before and after gelation;

[0034] Figure 6 This is a scanning electron microscope photograph of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 3 of the present invention after gelation;

[0035] Figure 7 These are photos of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 4 of the present invention before and after gelation;

[0036] Figure 8 This is a scanning electron microscope photograph of the resistance-increasing in-situ gel deep profile control agent prepared in Example 4 of the present invention after gelation. DETAILED DESCRIPTION

[0037] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments. Except for the following contents, the process of the present invention adopts conventional methods or devices in the art. Unless otherwise specified, the following terms have the meanings commonly understood by those skilled in the art.

[0038] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0039] Specifically, in a first aspect, the present invention provides a resistance-enhancing in-situ gel deep profile control agent, which is prepared using raw materials including the following components: water-soluble functional monomers, functional micro-nano particles, a gelation control agent and water.

[0040] At a certain temperature, the gelation control agent decomposes in water to produce free radicals, which in turn trigger a free radical polymerization reaction between water-soluble functional monomers and functional micro-nanoparticles, ultimately forming a three-dimensional network structure gel with micro-nanoparticles as cross-linking nodes, thereby blocking the crossflow channel.

[0041] The components of the resistance-enhancing in-situ gel deep profile control agent of the present invention are introduced in detail below:

[0042] Water-soluble functional monomers

[0043] The role of the water-soluble functional monomer is to provide hydrophilic segments for the three-dimensional network structure of the gel after polymerization.

[0044] In some preferred embodiments, the water-soluble functional monomer includes one or a mixture of polyethylene glycol (1000) monomethyl ether methacrylate, polyethylene glycol (2000) monomethyl ether methacrylate, polyethylene glycol (4000) monomethyl ether methacrylate, polyethylene glycol (6000) monomethyl ether methacrylate, polyethylene glycol (8000) monomethyl ether methacrylate, and acrylamide.

[0045] More preferably, the water-soluble functional monomer includes one or a mixture of polyethylene glycol (6000) monomethyl ether methacrylate, polyethylene glycol (8000) monomethyl ether methacrylate, and acrylamide.

[0046] The resistance-increasing in-situ gel deep profile control agent of the present invention comprises 3 to 8% by weight of a water-soluble functional monomer. For example, the water-soluble functional monomer may be present in a ratio of 3%, 4%, 5%, 6%, 7%, or 8% in the resistance-increasing in-situ gel deep profile control agent of the present invention.

[0047] In practice, when the proportion of water-soluble functional monomers in the resistance-increasing in-situ gel deep profile control agent of the present invention is less than 3%, the gelling strength of the profile control agent will be low (the gelling strength can only reach Class A of the Sydansk gel code method); when the proportion of water-soluble functional monomers in the resistance-increasing in-situ gel deep profile control agent of the present invention is more than 8%, the gelling time of the profile control agent will be too short (the gelling time is less than 2 days), which cannot meet the gelling time requirements for on-site deep flooding.

[0048] More preferably, the proportion of the water-soluble functional monomer in the resistance-increasing in-situ gel deep profile control agent of the present invention is 5-8%.

[0049] Functional micro-nanoparticles

[0050] The role of functional micro-nanoparticles is to provide cross-linking centers for the three-dimensional network structure of the gel after polymerization.

[0051] In some preferred embodiments, the functional micro-nanoparticles include one or a mixture of cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface and silica gel micro-nanoparticles with carbon-carbon double bonds on the surface.

[0052] Among them, cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface are prepared by emulsion polymerization at 45-55°C using diethylbenzene as a cross-linker, styrene as a hydrophobic monomer, acrylamide as a hydrophilic monomer, fatty alcohol polyoxyethylene ether sulfate (AES) as an emulsifier, and azobisisobutylamidine hydrochloride as an initiator.

[0053] In some preferred embodiments, the preparation method of cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on their surfaces is as follows: 77-79.5 g of deionized water, 0.5-3.0 g of fatty alcohol polyoxyethylene ether sulfate (AES), and 0.5 g of acrylamide are weighed into a three-necked flask at room temperature and stirred at 200 rpm to dissolve. Then, 1.5 g of diethylbenzene and 18 g of styrene are weighed into the flask and stirred at 400-500 rpm for emulsification for 30 minutes. While stirring and emulsification, nitrogen is introduced into the flask at a rate of 1 mL / min. After emulsification is completed, the flask is transferred to a constant temperature water bath while stirring is maintained. When the temperature reaches 55°C, 0.3-0.5 g of azobisisobutylamidine hydrochloride is added to the flask to initiate the reaction. After a constant temperature reaction for 3 hours, the temperature is lowered to room temperature and the reaction is terminated. Cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on their surfaces are obtained, with a particle size distribution ranging from 50 nm to 10 μm.

[0054] Among them, silica gel micro-nanoparticles with carbon-carbon double bonds on the surface are prepared by hydrolysis at 45-55°C using vinyltriethoxysilane as raw material and AES as emulsifier.

[0055] In some preferred embodiments, the preparation method of silica gel micro-nanoparticles with carbon-carbon double bonds on the surface is as follows: at room temperature, 84.5-89.0 g of deionized water and 0.5-1.0 g of emulsifier AES are weighed in a three-necked flask, stirred and dissolved at a stirring rate of 200 rpm, and then 10-15 g of vinyltriethoxysilane is weighed in the flask, stirred and emulsified at a stirring rate of 400-500 rpm for 30 minutes. After the emulsification is completed, the flask is transferred to a constant temperature water bath while maintaining stirring, the temperature is raised to 50°C, and after constant temperature reaction for 8 hours, the temperature is reduced to room temperature and the reaction is stopped to obtain silica gel micro-nanoparticles with carbon-carbon double bonds on the surface with a particle size distribution between 1 and 10 μm.

[0056] In some preferred embodiments, the particle size distribution of the functional micro-nanoparticles is between 50 nm and 10 μm.

[0057] In practice, when the particle size of functional micro-nano particles is less than 50nm, it will lead to too many cross-linking nodes, excessive cross-linking of the control and displacement system, and even the generation of floccules; when the particle size of functional micro-nano particles is greater than 10μm, it will lead to too few cross-linking nodes and a decrease in the gel strength of the control and displacement system.

[0058] The resistance-increasing in-situ gel deep profile control agent of the present invention comprises 0.5-2% by weight of functional micro-nano particles. For example, the functional micro-nano particles may be present in a ratio of 0.5%, 1%, 1.5% or 2% in the resistance-increasing in-situ gel deep profile control agent of the present invention.

[0059] Practice has shown that when the ratio of functional micro-nano particles is too large, it will lead to too many cross-linking nodes, excessive cross-linking of the flooding system, and even the generation of floccules; when the ratio of functional micro-nano particles is too small, it will lead to too few cross-linking nodes and a decrease in the gel strength of the flooding system.

[0060] More preferably, the proportion of the functional micro-nano particles in the resistance-increasing in-situ gel deep profile control agent of the present invention is 0.8-2%.

[0061] Gelation control agent

[0062] The function of the gelation control agent is to decompose and generate free radicals, which trigger free radical polymerization reaction between water-soluble functional monomers and functional micro-nanoparticles.

[0063] In some preferred embodiments, the gelling control agent includes one or a mixture of azobisisobutylimidazoline hydrochloride, azobisisopropylimidazoline, tert-butyl perbenzoate, tert-amyl hydroperoxide, and tert-butyl cumene peroxide.

[0064] More preferably, the gelling control agent is azodiisopropylimidazoline, tert-butyl perbenzoate, or tert-amyl hydroperoxide.

[0065] The resistance-increasing in-situ gel deep profile control agent of the present invention comprises 0.3-1% by weight of a gelling control agent. For example, the gelling control agent may be present in an amount of 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1% in the resistance-increasing in-situ gel deep profile control agent of the present invention.

[0066] Practice has shown that when the proportion of the gelling control agent is too large, the gelling time of the adjustment and displacement system will be too short (less than 1 day), which cannot meet the construction requirements; when the proportion of the gelling control agent is too small, the adjustment and displacement system will not gel.

[0067] More preferably, the proportion of the gelation control agent in the resistance-increasing in-situ gel deep profile control agent of the present invention is 0.4-0.8%.

[0068] water

[0069] The water used in the resistance-increasing in-situ gel deep profile control agent of the present invention is formation water or seawater.

[0070] More preferably, the maximum mineralization of the water used in the present invention is 30×10 4 mg / L.

[0071] In a second aspect, the present invention further provides a method for preparing a resistance-enhancing in-situ gel deep profile control agent, comprising:

[0072] (1) Add water-soluble functional monomers into water according to the ratio and stir to completely dissolve them;

[0073] (2) Add functional micro-nanoparticles according to the proportion under stirring and continue stirring until they are completely dissolved;

[0074] (3) Adding a gelling control agent according to the proportion, stirring to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0075] Among them, the ratio, composition and function of the water-soluble functional monomers, functional micro-nanoparticles, gelation control agent and water used in the preparation of the resistance-increasing in-situ gel deep profile control agent of the present invention are the same as those in the resistance-increasing in-situ gel deep profile control agent provided in the first aspect of the present invention, and the present invention will not repeat them here.

[0076] In some preferred embodiments, the preparation method of the resistance-increasing in-situ gel deep profile control agent of the present invention comprises: at room temperature, according to the mass percentage, first adding 3 to 8% of the water-soluble functional monomer to water, stirring for 5 minutes at a stirring rate of ≥20 rpm to completely dissolve it and prepare a functional monomer solution; then, while maintaining stirring, adding 0.5 to 2% of the functional micro-nano particles to the functional monomer solution, stirring for 5 minutes, so that it is evenly dispersed in the functional monomer solution; finally, adding 0.3 to 1% of the gelation control agent to the functional monomer solution, and continuing to stir for 5 minutes to obtain the resistance-increasing in-situ gel deep profile control agent.

[0077] The resistance-enhancing in-situ gel deep profile control agent prepared according to the method of the present invention has an initial viscosity of 1 to 2 mPa·s, a gelling time in an oil reservoir at 50 to 120° C. that can be adjusted between 5 and 15 days, and a dehydration rate of less than 10% at a constant temperature of 120° C. for 90 days after gelling.

[0078] Example

[0079] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. In the following examples, the experimental methods without specific conditions are based on conventional methods and conditions.

[0080] Example 1

[0081] (1) Preparation of cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface

[0082] At room temperature, 77 g of deionized water, 3 g of AES, and 0.5 g of acrylamide were weighed into a three-necked flask and stirred to dissolve at a stirring rate of 200 rpm. Then, 1.5 g of diethylbenzene and 18 g of styrene were weighed into the flask and stirred and emulsified at a stirring rate of 400-500 rpm for 30 minutes. While stirring and emulsifying, nitrogen was introduced into the flask at a rate of 1 mL / min. After the emulsification was completed, the flask was transferred to a constant temperature water bath while maintaining stirring. When the temperature rose to 55°C, 0.3-0.5 g of azobisisobutylamidine hydrochloride was added to the flask to initiate the reaction. After the constant temperature reaction for 3 hours, the temperature was reduced to room temperature and the reaction was stopped to obtain cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface and a particle size distribution between 50 nm and 2 μm.

[0083] (2) Preparation of resistance-enhancing in-situ gel deep profile control agent

[0084] At room temperature, polyethylene glycol (1000) monomethyl ether methacrylate 2% and acrylamide 3% were added according to mass percentage until the mineralization degree reached 10×10 4The method comprises the following steps: adding 1.5% cross-linked polystyrene micro-nanoparticles with a particle size distribution of 50 nm to 2 μm and carbon-carbon double bonds on the surface to the functional monomer aqueous solution, stirring for 5 minutes at a stirring rate of ≥20 rpm to completely dissolve the monomer, and preparing an aqueous solution with a total monomer mass percentage of 5%; while maintaining stirring, adding 1.5% cross-linked polystyrene micro-nanoparticles with a particle size distribution of 50 nm to 2 μm and carbon-carbon double bonds on the surface to the functional monomer aqueous solution, and stirring for 5 minutes to uniformly disperse the particles; while maintaining stirring, adding 0.5% azodiisopropylimidazoline to the functional monomer aqueous solution, and continuing to stir for 5 minutes to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0085] The initial viscosity of the profile control agent was measured to be 1.37 mPa·s, the gelling time at 60°C was 7 days, and the gelling strength could reach the E grade specified by the Sydansk gel code method. Figure 1 The microstructure after gelation is shown in the attached Figure 2 As shown. Figure 2 It can be seen from the figure that the profile control agent has a three-dimensional network structure with cross-linked polystyrene micro-nanoparticles as cross-linking nodes after gelation.

[0086] Example 2

[0087] (1) Preparation of cross-linked polystyrene micro-nanoparticles with carbon-carbon double bonds on the surface

[0088] At room temperature, 79.5 g of deionized water, 0.5 g of AES, and 0.5 g of acrylamide were weighed into a three-necked flask and stirred to dissolve at a stirring rate of 200 rpm. Then, 1.5 g of diethylbenzene and 18 g of styrene were weighed into the flask and stirred and emulsified at a stirring rate of 400-500 rpm for 30 minutes. While stirring and emulsifying, nitrogen was introduced into the flask at a rate of 1 mL / min. After the emulsification was completed, the flask was transferred to a constant temperature water bath while maintaining stirring. When the temperature rose to 55°C, 0.3-0.5 g of azobisisobutylamidine hydrochloride was added to the flask to initiate the reaction. After the constant temperature reaction for 3 hours, the temperature was reduced to room temperature and the reaction was stopped to obtain cross-linked polystyrene micro-nanoparticles with a particle size distribution between 1 and 10 μm and carbon-carbon double bonds on the surface.

[0089] (2) Preparation of resistance-enhancing in-situ gel deep profile control agent

[0090] At room temperature, polyethylene glycol (2000) monomethyl ether methacrylate 2%, polyethylene glycol (4000) monomethyl ether 1% and acrylamide 3% were added according to mass percentage to a solution with a mineralization degree of 20×10 4The method comprises the following steps: adding 0.8% cross-linked polystyrene micro-nanoparticles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface to the functional monomer aqueous solution under the condition of maintaining stirring, and stirring for 5 minutes to uniformly disperse the particles; and adding 0.7% tert-butyl peroxybenzoate to the functional monomer aqueous solution under the condition of maintaining stirring, and continuing to stir for 5 minutes to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0091] The initial viscosity of the profile control agent was measured to be 1.51 mPa·s, the gelling time at 90°C was 7 days, and the gelling strength could reach the E grade specified by the Sydansk gel code method. Figure 3 The microstructure after gelation is shown in the attached Figure 4 As shown. Figure 4 It can be seen from the figure that the profile control agent has a three-dimensional network structure with cross-linked polystyrene micro-nanoparticles as cross-linking nodes after gelation.

[0092] Example 3

[0093] (1) Preparation of silica gel micro-nanoparticles with carbon-carbon double bonds on the surface

[0094] At room temperature, 84.5 g of deionized water and 0.5 g of AES were weighed into a three-necked flask and stirred to dissolve at a stirring rate of 200 rpm. Then, 15 g of vinyltriethoxysilane was weighed into the flask and stirred and emulsified at a stirring rate of 400-500 rpm for 30 minutes. After the emulsification was completed, the flask was transferred to a constant temperature water bath while maintaining stirring. The temperature was raised to 50°C and the reaction was carried out at a constant temperature for 8 hours. The temperature was then returned to room temperature and the reaction was stopped to obtain silica gel micro-nanoparticles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface.

[0095] (2) Preparation of resistance-enhancing in-situ gel deep profile control agent

[0096] At room temperature, 3% polyethylene glycol (6000) monomethyl ether methacrylate, 3% polyethylene glycol (8000) monomethyl ether methacrylate and 2% acrylamide were added according to mass percentage until the mineralization degree reached 30×10 4The method comprises the following steps: adding 1% silica gel micro-nano particles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface to the functional monomer aqueous solution at a stirring rate of ≥20 rpm for 5 minutes to completely dissolve the monomers and prepare an aqueous solution with a total monomer mass percentage of 8%; while maintaining stirring, adding 1% silica gel micro-nano particles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface to the functional monomer aqueous solution and stirring for 5 minutes to uniformly disperse the particles; while maintaining stirring, adding 0.3% tert-amyl hydroperoxide and 0.3% tert-butyl peroxide isopropyl benzene to the functional monomer aqueous solution to adjust the total concentration of the gelation control agent in the functional monomer aqueous solution to 0.6%; and continuing stirring for 5 minutes to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0097] The initial viscosity of the profile control agent was measured to be 1.63 mPa·s, the gelling time at 120°C was 7 days, and the gelling strength could reach the E grade specified by the Sydansk gel code method. Figure 5 The microstructure after gelation is shown in the attached Figure 6 As shown. Figure 6 It can be seen from the figure that the profile control agent has a three-dimensional network structure with silica gel micro-nano particles as cross-linking nodes after gelation.

[0098] Example 4

[0099] Preparation of resistance-enhancing in-situ gel deep profile control agent

[0100] At room temperature, polyethylene glycol (1000) monomethyl ether methacrylate 2% and acrylamide 4% were added according to mass percentage to a mineralization degree of 10×10 4 The present invention relates to a method for preparing a functional monomer aqueous solution comprising the steps of: adding a first monomer to a functional monomer aqueous solution containing 1% silica gel micro-nanoparticles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface (prepared by the same method as in Example 3) and adding a second monomer to a functional monomer aqueous solution containing 1% silica gel micro-nanoparticles with a particle size distribution of 1 to 10 μm and carbon-carbon double bonds on the surface (prepared by the same method as in Example 2) to the functional monomer aqueous solution, stirring for 5 minutes to uniformly disperse the particles; and adding a second monomer aqueous solution containing 0.4% azobisisobutylimidazoline hydrochloride and stirring for 5 minutes to obtain a resistance-enhancing in-situ gel deep profile control agent.

[0101] The initial viscosity of the profile control agent was measured to be 1.36 mPa·s, the gelling time at 50°C was 7 days, and the gelling strength could reach the E grade specified by the Sydansk gel code method. Figure 7 The microstructure after gelation is shown in the attached Figure 8 As shown. Figure 8It can be seen from the figure that the profile control agent has a three-dimensional network structure with silica gel micro-nano particles and cross-linked polystyrene micro-nano particles as cross-linking nodes after gelation.

[0102] Test Example 1: Determining the injectability and plugging properties of a resistance-enhancing in-situ gel deep profile control agent

[0103] To illustrate the beneficial effects of the present invention, an artificial core having a porosity of 23.6%, a permeability of 1500 mD, and dimensions of Φ2.5 cm × 10 cm was used to test the injectability and plugging properties of the resistance-enhancing in-situ gel deep profile control agent prepared in Examples 1 to 4 and an existing weak gel profile control system (the system is composed of 0.3% polyacrylamide with a molecular weight of 10,000,000,000, 0.3% water-soluble phenolic resin crosslinker, and 0.3% ammonium chloride. To ensure sufficient dissolution of the polymer, the system was prepared in deionized water. The initial viscosity of the system was determined to be 175 mPa·s). The specific testing steps are as follows:

[0104] First, the core was vacuumed and saturated with water. Then, the core was placed in a core holder and 1 pore volume (PV) of profile control agent was injected into the core at an injection rate of 3 mL / min, and the maximum injection pressure was recorded. After the injection of the profile control agent was completed, the valves at both ends of the core holder were closed and the temperature was kept constant at the set temperature for 7 days. After the constant temperature was completed, the valves at both ends of the core holder were opened and water was injected into the core at an injection rate of 3 mL / min. The breakthrough pressure and the permeability after plugging K1 were measured, and the plugging rate was calculated.

[0105] The plugging rate is calculated using the following formula:

[0106]

[0107] The measurement results are shown in Table 1.

[0108] Table 1 Test results of injectability and plugging performance of resistance-enhancing in-situ gel deep profile control agent and weak gel profile control system

[0109]

[0110] The results in Table 1 show that the maximum injection pressure for the 1PV-injected resistance-enhancing in-situ gel deep profile control agents prepared in Examples 1-4 ranges from 0.4 to 0.8 MPa, while the maximum injection pressure for the 1PV-injected weak gel profile control system is 1.5 MPa. This demonstrates that, in reservoirs with the same porosity and permeability, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention significantly outperforms existing weak gel profile control systems in terms of injectability, enabling profile control at deeper depths in the reservoir. At a set temperature, after gelling in the core, the resistance-enhancing in-situ gel deep profile control agents prepared in Examples 1-4 achieved a plugging rate exceeding 97% and a breakthrough pressure exceeding 15 MPa, while the existing weak gel profile control system achieved a plugging rate of 80.7% and a breakthrough pressure of 2.3 MPa. This demonstrates that, in reservoirs with the same porosity and permeability, the resistance-enhancing in-situ gel deep profile control agent provided by the present invention significantly outperforms existing weak gel profile control systems in terms of plugging performance, effectively blocking strong water channeling channels in the reservoir.

[0111] Test Example 2: Determination of the temperature resistance of the resistance-enhancing in-situ gel deep profile control agent

[0112] To illustrate the beneficial effects of the present invention, the temperature resistance of the resistance-enhancing in-situ gel deep profile control agent prepared in Examples 1 to 4 and an existing weak gel profile control system (the system is composed of 0.3% polyacrylamide with a molecular weight of 10 million, 0.3% water-soluble phenolic resin crosslinker, and 0.3% ammonium chloride. To ensure sufficient dissolution of the polymer, the system was prepared in deionized water) was measured. The specific measurement steps are as follows:

[0113] First, 100 mL of the resistance-enhancing in-situ gel deep profile control agent prepared in Examples 1 to 4 and the existing weak gel profile control system were respectively loaded into high-temperature and high-pressure aging tanks and kept at a set temperature for 7 days to allow them to gel; after gelation, the high-temperature and high-pressure aging tanks were placed in an environment of 120°C and aged for 90 days. The dewatering amount V1 was measured and the dehydration rate was calculated. The dehydration rate was used as an indicator to measure the temperature resistance of the profile control agent.

[0114] The water separation rate of the profile control agent is calculated using the following formula:

[0115]

[0116] The measurement results are shown in Table 2.

[0117] Table 2 Temperature resistance test results of resistance-enhancing in-situ gel deep profile control agent and weak gel profile control system

[0118]

[0119] The results shown in Table 2 indicate that the resistance-enhancing in-situ gel deep profile control agents prepared in Examples 1-4 all exhibited dehydration rates below 7% after gelation at 120°C for 90 days, while the weak gel profile control system was completely dehydrated after 90 days at 120°C. This demonstrates that the resistance-enhancing in-situ gel deep profile control agent provided by the present invention has excellent temperature resistance and can be used for deep profile control in high-temperature reservoirs at 120°C.

[0120] Test Example 3: Determination of the Controllable Performance of the Gelation Time of a Resistance-Increasing In-Situ Gel Deep Profile Control Agent

[0121] To illustrate the beneficial effects of the present invention, the gelation time was measured at 90°C, using the time required for the gel strength to reach Grade E as defined by the Sydansk gel code method. The gelation time was determined for Example 2, maintaining the same dosage and composition of the functional monomer and functional micro / nanoparticles, while varying only the dosage of the gelation control agent. The results are shown in Table 3.

[0122] Table 3 Results of the control performance of the gelation time of the resistance-enhancing in-situ gel deep profile control agent

[0123]

[0124] The results shown in Table 3 indicate that the gelation time of the resistance-enhancing in-situ gel deep profile control agent prepared in Example 2 increases as the amount of gelation control agent added decreases. This indicates that the time it takes for the resistance-enhancing in-situ gel deep profile control agent provided by the present invention to react and gel in the formation can be flexibly adjusted within a range of 5 to 15 days by adjusting the amount and combination of gelation control agents added.

[0125] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0126] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0127] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A resistance-increasing in-situ gel deep profile control agent, characterized in that: The preparation method is prepared by using raw materials including the following components by weight: 3-8% of water-soluble functional monomer, 0.5-2% of functional micro-nano particles, 0.3-1% of gelation control agent and the balance of water.

2. The resistance-increasing in-situ gel deep profile control agent according to claim 1, characterized in that: The preparation method is prepared by using the following raw materials in percentage by weight: 5-8% of water-soluble functional monomer, 0.8-2% of functional micro-nano particles, 0.4-0.8% of gelling control agent and the balance of water.

3. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The water-soluble functional monomer includes one or a mixture of polyethylene glycol (1000) monomethyl ether methacrylate, polyethylene glycol (2000) monomethyl ether methacrylate, polyethylene glycol (4000) monomethyl ether methacrylate, polyethylene glycol (6000) monomethyl ether methacrylate, polyethylene glycol (8000) monomethyl ether methacrylate, and acrylamide.

4. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The functional micro-nano particles include one or a mixture of cross-linked polystyrene micro-nano particles with carbon-carbon double bonds on the surface and silicon dioxide gel micro-nano particles with carbon-carbon double bonds on the surface.

5. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The functional micro-nano particles have a particle size distribution between 50nm and 10μm.

6. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The gelling control agent comprises one or a mixture of azobisisobutylimidazoline hydrochloride, azobisisopropylimidazoline, tert-butyl perbenzoate, tert-amyl hydroperoxide, and tert-butyl cumene peroxide.

7. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The water is formation water or sea water.

8. The resistance-increasing in-situ gel deep profile control agent according to claim 1 or 2, characterized in that: The mineralization of the water is at most 30×10 4 mg / L.

9. The method for preparing the resistance-increasing in-situ gel deep profile control agent according to any one of claims 1 to 8, characterized in that: include: (1) Add water-soluble functional monomers into water according to the ratio and stir to completely dissolve them; (2) Add functional micro-nanoparticles according to the proportion under stirring and continue stirring until they are completely dissolved; (3) Adding a gelling control agent according to the proportion, stirring to obtain a resistance-enhancing in-situ gel deep profile control agent.

10. The method for preparing the resistance-increasing in-situ gel deep profile control agent according to claim 9, characterized in that: The stirring rate in steps (1) to (3) is ≥20 rpm.

11. A resistance-increasing in-situ gel deep profile control agent, characterized in that: The product is prepared by the preparation method according to any one of claims 9 to 10.

12. The resistance-increasing in-situ gel deep profile control agent according to any one of claims 1 to 8 or 11, characterized in that: The resistance-increasing in-situ gel deep profile control agent has an initial viscosity of 1-2 mPa·s, a controllable gelling time of 5-15 days in an oil reservoir at 50-120°C, and a dehydration rate of less than 10% at a constant temperature of 120°C for 90 days after gelling.

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