阅读说明：本技术 贻贝仿生凝胶组合物、自修复凝胶和调堵剂及其制备方法和应用 (Mussel bionic gel composition, self-repairing gel and plugging agent as well as preparation method and application of mussel bionic gel composition and self-repairing gel and plugging agent ) 是由 戴彩丽 李琳 刘佳伟 徐忠正 赵光 赵明伟 吴一宁 孙永鹏 于 2020-11-17 设计创作，主要内容包括：本发明涉及低渗裂缝性油藏调堵剂领域,公开了贻贝仿生凝胶组合物、自修复凝胶和自生长凝胶粒子调堵剂及其制备方法和应用。该贻贝仿生凝胶组合物包括：贻贝仿生共聚物和/或贻贝仿生复合物、交联剂和水；其中,所述贻贝仿生共聚物包含来自乙烯基类单体的结构单元A和来自含有乙烯基的贻贝仿生邻苯二酚类基团单体的结构单元B；所述贻贝仿生复合物包括聚丙烯酰胺和贻贝仿生邻苯二酚类化合物。由该组合物制得的自生长凝胶粒子调堵剂初始表观粘度低,易注入,远运移,具有很好的剪切修复性能,特别适用于低渗裂缝性油藏,调整微裂缝网络,改善裂缝流道,提高水驱效率,提高采收率。(The invention relates to the field of a plugging agent for a low-permeability fractured reservoir, and discloses a mussel bionic gel composition, a self-repairing gel and a self-growing gel particle plugging agent, and a preparation method and application thereof. The mussel biomimetic gel composition comprises: mussel biomimetic copolymer and/or mussel biomimetic complex, cross-linking agent and water; wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers; the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds. The self-growing gel particle plugging agent prepared from the composition has low initial apparent viscosity, is easy to inject, has long migration and good shearing and repairing performance, is particularly suitable for low-permeability fractured oil reservoirs, adjusts a micro-fracture network, improves fracture flow channels, improves water flooding efficiency and improves recovery ratio.)

1. A mussel biomimetic gel composition for preparing a self-healing gel, the composition comprising: mussel biomimetic copolymer and/or mussel biomimetic complex, cross-linking agent and water;

wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers;

the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds.

2. A composition according to claim 1, wherein the mussel biomimetic copolymer has a degree of hydrolysis of 5-28 mol%, preferably 10-18 mol%; the weight average molecular weight is 700-1000 ten thousand g/mol, preferably 800-900 ten thousand g/mol; the complete dissolution time is less than 1.5 h;

preferably, the degree of hydrolysis of the polyacrylamide is 5 to 28 mol%, preferably 5 to 17 mol%; the weight average molecular weight is 700-1500 ten thousand g/mol, preferably 800-1200 ten thousand g/mol; the complete dissolution time is less than 1.5 h;

preferably, the mussel biomimetic copolymer is used in an amount of 0.2-0.6 parts by weight, preferably 0.25-0.4 parts by weight; the mussel bionic compound is used in an amount of 0.2-0.6 weight parts, preferably 0.25-0.4 weight parts; the amount of the cross-linking agent is 0.6-1.5 parts by weight, preferably 0.8-1.2 parts by weight; the amount of the water is 97.9 to 99.2 parts by weight, preferably 98.4 to 98.95 parts by weight;

preferably, the content of the structural unit A is 75-90 wt%, preferably 85-90 wt%, and the content of the structural unit B is 10-25 wt%, preferably 10-15 wt%, based on the total weight of the mussel biomimetic copolymer;

preferably, the polyacrylamide is present in an amount of 65 to 85 wt%, preferably 75 to 80 wt%, based on the total weight of the mussel biomimetic composite; the content of the mussel bionic catechol compound is 15-35 wt%, preferably 20-25 wt%.

3. The composition of claim 1 or 2, wherein the vinyl-containing mussel biomimetic catechol-based monomer is selected from one or more of compounds having a structure represented by formula (1),

wherein R is₁is-H or-CH₃；

Preferably, the mussel biomimetic catechol compound is selected from one or more compounds with the structure shown in the formula (2),

wherein R is₂is-COOH, -OH, -C_nH_2nNH₂、-(CHO)_x-and-C_nH_2n+1And/or R₃is-H or-OH;

preferably, x is an integer from 1 to 6, and/or n is an integer from 1 to 12;

preferably, the mussel biomimetic catechol compound is selected from one or more of dopamine, tannic acid, catechin, ellagic acid and gallic acid, more preferably dopamine and/or tannic acid;

preferably, the vinyl monomer is selected from one or more of acrylic acid, methacrylic acid, ethacrylic acid, propyl acrylic acid, butyl acrylic acid, amyl acrylic acid, hexyl acrylic acid, acrylamide, methacrylamide, ethyl acrylamide, propyl acrylamide, butyl acrylamide, amyl acrylamide and hexyl acrylamide, and is more preferably acrylamide and/or acrylic acid;

preferably, the cross-linking agent is selected from one or more of water-soluble phenolic resin, polyethyleneimine and polypropyleneimine, more preferably water-soluble phenolic resin and/or polyethyleneimine;

preferably, the weight average molecular weight of the water-soluble phenolic resin is 5000-30000 g/mol; the weight average molecular weight of the polyethyleneimine is 1500-10000 g/mol.

4. A self-repairing gel is characterized in that the gel is formed by aging and gelling a composition comprising a mussel bionic copolymer and/or a mussel bionic compound, a cross-linking agent and water;

wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers;

the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds;

preferably, the rheological elastic modulus of the gel is 3-15Pa, and the viscous modulus is 1-3 Pa;

preferably, the conditions for aging to form gel include: the temperature is 60-90 ℃ and the time is 24-72 h.

5. A preparation method of self-repairing gel is characterized by comprising the following steps:

(1a) in the presence of an initiator and a chain transfer agent, carrying out copolymerization reaction on a vinyl monomer and a mussel bionic catechol group monomer containing vinyl to obtain a mussel bionic copolymer; and/or

(1b) Mixing the mussel bionic catechol compound aqueous solution with the polyacrylamide aqueous solution to obtain a mussel bionic compound;

(2) aging the mussel bionic copolymer and/or the mussel bionic compound and a cross-linking agent to form gel, thereby obtaining the self-repairing gel.

6. The preparation method according to claim 5, wherein, in step (1a), the mussel biomimetic catechol-group containing vinyl group monomer is selected from one or more compounds having a structure represented by formula (1),

wherein R is₁is-H or-CH₃；

Preferably, in step (1b), the mussel biomimetic catechol compound is selected from one or more of compounds having a structure represented by formula (2),

wherein R is₂is-COOH, -OH, -C_nH_2nNH₂、-(CHO)_x-and-C_nH_2n+1And/or R₃is-H or-OH;

preferably, x is an integer from 1 to 6, and/or n is an integer from 1 to 12;

preferably, the mussel biomimetic catechol compound is selected from one or more of dopamine, tannic acid, catechin, ellagic acid and gallic acid, more preferably dopamine and/or tannic acid;

preferably, the vinyl monomer is selected from one or more of acrylic acid, methacrylic acid, ethacrylic acid, propyl acrylic acid, butyl acrylic acid, amyl acrylic acid, hexyl acrylic acid, acrylamide, methacrylamide, ethyl acrylamide, propyl acrylamide, butyl acrylamide, amyl acrylamide and hexyl acrylamide, and is more preferably acrylamide and/or acrylic acid;

preferably, the cross-linking agent is selected from one or more of water-soluble phenolic resin, polyethyleneimine and polypropyleneimine, more preferably water-soluble phenolic resin and/or polyethyleneimine;

preferably, the weight average molecular weight of the water-soluble phenolic resin is 5000-30000 g/mol; the weight average molecular weight of the polyethyleneimine is 1500-10000 g/mol;

preferably, the mussel biomimetic copolymer has a degree of hydrolysis of 5 to 28 mol%, more preferably 10 to 18 mol%; the weight average molecular weight is 700-1000 ten thousand g/mol, more preferably 800-900 ten thousand g/mol; the complete dissolution time is less than 1.5 h;

preferably, the degree of hydrolysis of the polyacrylamide is from 5 to 28 mol%, more preferably from 5 to 17 mol%; the weight average molecular weight is 700-1500 ten thousand g/mol, more preferably 800-1200 ten thousand g/mol; the complete dissolution time is less than 1.5 h.

7. The method according to claim 5 or 6, wherein in the step (1a), the weight ratio of the vinyl monomer, the mussel biomimetic catechol-based monomer containing vinyl, the initiator and the chain transfer agent is 61-76: 7-12: 0.08-0.15: 0.2-0.5;

preferably, the initiator is selected from azobisisobutyramidine hydrochloride and/or azobisisobutyrimidazoline hydrochloride; the chain transfer agent is selected from one or more of water-soluble dithiocarbonate, water-soluble xanthate and water-soluble trithiocarbonate, and is more preferably water-soluble xanthate and/or water-soluble trithiocarbonate;

preferably, in the step (1b), the weight ratio of the mussel biomimetic catechol compound to the polyacrylamide is 5-10: 25-30;

preferably, in step (2), the weight ratio of said mussel biomimetic copolymer and/or said mussel biomimetic complex to cross-linking agent is from 0.2 to 0.5: 6-1.2;

preferably, in the step (1a), the temperature of the copolymerization reaction is 55-70 ℃ and the time is 4-8 h;

preferably, in the step (2), the temperature for gelling is 60-90 ℃ and the time is 24-72 h.

8. Self-healing gel prepared by the process according to any one of claims 5 to 7, preferably having a rheological elastic modulus of between 3 and 15Pa and a viscous modulus of between 1 and 3 Pa.

9. A self-growing gel particle profile control agent, which is characterized in that the profile control agent is formed by blending and shearing the self-repairing gel of claim 4 or 8 and water;

preferably, the weight ratio of the self-repairing gel to water is 1-2: 0.5 to 6;

preferably, the primary particle size of the plugging agent is 200-5000nm, and the primary apparent viscosity is 3-15 mPas.

10. Use of the self-growing gel particle plugging agent of claim 9 in a low permeability fractured reservoir.

Technical Field

The invention relates to the field of hypotonic fractured reservoir plugging agents, in particular to a mussel bionic gel composition, a method for preparing a self-repairing gel from the mussel bionic gel composition, the self-repairing gel prepared by the method, a method for preparing a self-growing gel particle plugging agent from the self-growing gel particle plugging agent prepared by the method, and application of the self-growing gel particle plugging agent in a hypotonic fractured reservoir.

Background

Natural fractures of the hypotonic/ultra-hypotonic oil reservoir relatively develop, the artificial fractures can aggravate the heterogeneity of a matrix-fracture reservoir, injected fluid easily flows along the fractures, and injected water, chemical agents and the like cannot effectively act on a target layer to achieve effective sweeping and oil washing. The conventional gel plugging agent is easily influenced by multiple shearing, formation water dilution, rock adsorption and the like in the processes of injection and migration; the polymer microsphere has harsh polymerization production conditions and equipment requirements and poor stratum adaptability; the pre-crosslinked bulk-expanded particles have good expansibility, and can easily block small crack channels of a low-permeability reservoir. Aiming at low-permeability fractured reservoirs, the conventional plugging agent still has the problems of high initial viscosity, poor injection performance, difficult migration capability in fractures and the like.

CN104910882A discloses a flexible gel particle and a flexible gel particle plugging agent prepared from the same, wherein the flexible gel particle is polymerized from acrylamide, a temperature-resistant monomer and an alkali-resistant and salt-resistant monomer, although the flexible gel particle plugging agent prepared from the flexible gel particle is environment-friendly, low in cost and simple in preparation process, the particle size of the flexible gel particle is larger, and the flexible gel particle is not suitable for being injected and transported in a low-permeability fracture oil reservoir within a millimeter range (1-5mm), and in addition, the strength of the flexible gel particle is also larger, so that a small fracture channel is easily plugged.

CN110734754A discloses a drilling fluid plugging agent composition, a plugging agent, a preparation method and an application thereof, wherein the plugging agent composition contains a bionic mussel adhesive, nano-clay, vinyl monomers, a cross-linking agent and water. The plugging agent while drilling prepared by the plugging agent composition has strong high temperature resistance of 180 ℃, can effectively plug a sand tray leaking layer with the maximum pore radius of 50-100mD, has the pressure bearing capacity of more than 4MPa, is suitable for the requirement of drilling fluid, and does not relate to the field of oilfield development.

Disclosure of Invention

The invention aims to solve the problems of high initial apparent viscosity, poor injection performance and difficult migration capability in a fracture when a plugging agent is applied to a low-permeability fractured reservoir in the prior art, and provides a mussel bionic gel composition, a self-repairing gel and a self-growing gel particle plugging agent, and a preparation method and application thereof.

To achieve the above objects, a first aspect of the present invention provides a mussel biomimetic gel composition for preparing a self-healing gel, the composition comprising: mussel biomimetic copolymer and/or mussel biomimetic complex, cross-linking agent and water;

wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers;

the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds.

In a second aspect, the invention provides a self-healing gel, which is formed by aging a composition comprising a mussel biomimetic copolymer and/or a mussel biomimetic complex, a cross-linking agent and water to form a gel;

wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers;

the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds.

The third aspect of the invention provides a preparation method of self-repairing gel, which comprises the following steps:

(1a) in the presence of an initiator and a chain transfer agent, carrying out copolymerization reaction on a vinyl monomer and a mussel bionic catechol group monomer containing vinyl to obtain a mussel bionic copolymer; and/or

(1b) Mixing the mussel bionic catechol compound aqueous solution with the polyacrylamide aqueous solution to obtain a mussel bionic compound;

(2) aging the mussel bionic copolymer and/or the mussel bionic compound and a cross-linking agent to form gel, thereby obtaining the self-repairing gel.

In a fourth aspect, the present invention provides a self-healing gel prepared by the method as described above.

The invention provides a self-growing gel particle profile control agent, which is formed by blending and shearing the self-repairing gel and water.

In a sixth aspect, the invention provides the use of a self-growing gel particle plugging agent as described above in a low permeability fractured reservoir.

Through the technical scheme, the invention has the following advantages:

(1) the self-growing gel particle plugging agent has low initial apparent viscosity (3-15mPa & s), is easy to inject and far migrate, is not easy to block the stratum near a well, is not influenced by shearing in the injection and migration processes, has good shearing and repairing performance, and can realize self-repairing after the block gel is damaged;

(2) the particle size of the self-growing gel particle plugging agent is 200-5000nm, and the particles can aggregate and grow automatically at the formation temperature (less than or equal to 110 ℃) and the mineralization degree (less than or equal to 150000mg/L), so that the strength of the plugging agent is increased;

(3) the self-growing gel particle plugging agent can be uniformly and stably dispersed at room temperature, and is favorable for short-term storage and transportation;

(4) the self-growing gel particle plugging agent is suitable for low-permeability fractured reservoirs, and provides a solution for fracture channeling and micro-fracture network adjustment.

Drawings

FIG. 1 is a molecular weight test gel chromatogram of a mussel biomimetic copolymer according to example 1 of the invention;

FIG. 2 is a graph of the self-healing gel modulus versus time for example 1 of the present invention;

FIG. 3 is a graph of oscillating strain scan of self-healing gel in accordance with example 1 of the present invention;

FIG. 4 is a graph showing the distribution of the particle size of the self-growing gel particle plugging agent of example 1 of the present invention;

FIG. 5 is a graph of oscillating strain scan of self-healing gel in accordance with example 2 of the present invention;

FIG. 6 is a graph showing the distribution of the particle size of the self-growing gel particle plugging agent of example 2 of the present invention.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the present invention provides a mussel biomimetic gel composition for preparing a self-healing gel, the composition comprising: mussel biomimetic copolymer and/or mussel biomimetic complex, cross-linking agent and water.

Although the prior patent document (CN110734754A) mentions that the introduction of the mussel-like adhesive rich in catechol functional groups into the plugging agent composition can enhance the adhesion performance of the plugging agent and improve the compressive strength, the inventor of the invention finds that the gel particles of the plugging agent introduce catechol structures and interact with a cross-linking agent structure used for preparing the gel, so that covalent chemical interaction and non-covalent interaction (such as hydrogen bonds, cation-pi, pi-pi, hydrophobicity and the like) can be generated between the gel and the gel particles, and the functions of self-repairing of the gel and self-growing of the gel particles are realized. In consideration of the environments (reservoir temperature, mineralization ions and the like) faced by the plugging agent in the hypotonic fractured reservoir and the conditions available thereby, in some embodiments of the invention, the catechol-type structure contained in the mussel biomimetic copolymer and/or mussel biomimetic composite is combined with the interaction with the cross-linking agent structure used for preparing the gel, so that on one hand, the gel has self-repairing capability after being damaged, and the gel particles have environmental response self-growth capability in the formation temperature, mineralization and submerged environment; on the other hand, the water-based plugging agent has an adhesion effect on the rock wall surface, and the retention stability of the plugging agent particles is enhanced.

In some embodiments of the invention, the mussel biomimetic copolymer comprises structural units a from a vinyl-based monomer and structural units B from a vinyl-containing mussel biomimetic catechol-based monomer.

In some embodiments of the present invention, in order to facilitate the dissolution of the polymer in water, reduce the time required for the dissolution of the polymer formulation, meet the requirement of lower initial viscosity, and improve the long-term stability of the polymer structure in the aging environment, preferably, the mussel biomimetic copolymer has a degree of hydrolysis of 5 to 28 mol%, more preferably 10 to 18 mol%, and a complete dissolution time of less than 1.5 h. The aggregation form of the polymer with a hydrolysis degree structure in water is beneficial to the cross-linking reaction with the cross-linking agent, and the viscoelastic property of the gel is enhanced.

In some embodiments of the present invention, in order to improve the strength of the gel and the gel particles under the temperature and the mineralization degree, so that the gel and the gel particles have better toughness, preferably, the weight average molecular weight of the mussel biomimetic copolymer is 700 ten thousand to 1000 ten thousand g/mol, more preferably 800 ten thousand to 900 ten thousand g/mol.

In some embodiments of the invention, the mussel biomimetic complex comprises polyacrylamide and mussel biomimetic catechol-type compounds.

In some embodiments of the present invention, in order to facilitate the dissolution of the polymer in water, reduce the dissolution time required for the polymer formulation, meet the requirement of lower initial viscosity, and improve the aging long-term stability of the polymer structure in the formation environment, it is preferred that the polyacrylamide has a degree of hydrolysis of 5 to 28 mol%, more preferably 5 to 17 mol%, and a complete dissolution time of less than 1.5 h. The aggregation form of the polymer with a hydrolysis degree structure in water is beneficial to the cross-linking reaction with the cross-linking agent, and the viscoelastic property of the gel is enhanced.

In some embodiments of the present invention, in order to improve the strength of the gel and the gel particles under the conditions of temperature and mineralization degree, and to provide the gel and the gel particles with better toughness, the polyacrylamide preferably has a weight average molecular weight of 700 ten thousand to 1500 ten thousand g/mol, and more preferably 800 ten thousand to 1200 ten thousand g/mol.

In some embodiments of the present invention, the polyacrylamide can be obtained commercially, for example, from the mclin reagent company, or can be prepared by various methods known to those skilled in the art, and the preparation method can be known to those skilled in the art, and will not be described herein again.

In some embodiments of the present invention, in order to improve the adhesive property of the gel and reduce the cost, it is preferable that the mussel biomimetic copolymer is used in an amount of 0.2-0.6 parts by weight, the mussel biomimetic complex is used in an amount of 0.2-0.6 parts by weight, the cross-linking agent is used in an amount of 0.6-1.5 parts by weight, and the water is used in an amount of 97.9-99.2 parts by weight;

in some embodiments of the present invention, more preferably, the mussel biomimetic copolymer is present in an amount of 0.25 to 0.35 parts by weight, the mussel biomimetic complex is present in an amount of 0.05 to 0.15 parts by weight, the cross-linking agent is present in an amount of 0.6 to 1.2 parts by weight, and the water is present in an amount of 98.3 to 99.1 parts by weight, based on the total weight of the composition.

In some embodiments of the present invention, the content of the structural unit a is 75 to 90 wt%, preferably 85 to 90 wt%, based on the total weight of the mussel biomimetic copolymer; the content of the structural unit B is 10 to 25% by weight, preferably 10 to 15% by weight.

In some embodiments of the present invention, the polyacrylamide is present in an amount of 65 to 85 wt%, preferably 75 to 80 wt%, based on the total weight of the mussel biomimetic composite; the content of the mussel bionic catechol compound is 15-35 wt%, preferably 20-25 wt%.

In some embodiments of the present invention, the mussel biomimetic catechol-based monomer containing a vinyl group is selected from one or more compounds having a structure represented by formula (1),wherein R is₁is-H or-CH₃(i.e., 3-acrylamidodopamine and/or 3-methacrylamidoparnine).

In some embodiments of the present invention, the mussel biomimetic catechol compound may be a mussel biomimetic catechol compound natural or synthesized in the art, for example, one or more polyphenols such as dopamine, tannic acid, catechin, ellagic acid, and gallic acid.

In some embodiments of the present invention, preferably, the mussel biomimetic catechol compound is selected from one or more of compounds having a structure represented by formula (2),wherein R is₂is-COOH, -OH, -C_nH_2nNH₂、-(CHO)_x-and-C_nH_2n+1More preferably, x is an integer of 1 to 6, and/or n is an integer of 1 to 12.

In some embodiments of the present invention, preferably, the mussel biomimetic catechol compound is selected from one or more of compounds having a structure represented by formula (2),wherein R is₃is-H or-OH.

In some embodiments of the present invention, preferably, the mussel biomimetic catechol compound is selected from dopamine and/or tannic acid.

In some embodiments of the present invention, the vinyl monomer may be selected from one or more of acrylic acid, methacrylic acid, ethacrylic acid, propylacrylic acid, butylacrylic acid, pentylacrylic acid, and hexylacrylic acid, preferably acrylic acid; the acrylamide can also be selected from one or more of acrylamide, methacrylamide, ethyl acrylamide, propyl acrylamide, butyl acrylamide, amyl acrylamide and hexyl acrylamide, and is preferably acrylamide.

In some embodiments of the present invention, the cross-linking agent is selected from one or more of water-soluble phenolic resin, polyethyleneimine and polypropyleneimine, preferably, the cross-linking agent is selected from water-soluble phenolic resin and/or polyethyleneimine.

In some embodiments of the present invention, in order to improve the network strength after crosslinking inside the gel, avoid the problem of dehydration or brittleness at high temperature, and enhance the growth of gel particles in the formation water environment, preferably, the weight average molecular weight of the water-soluble phenolic resin is 30000g/mol which is 5000-; preferably, the weight average molecular weight of the polyethyleneimine is 1500-10000 g/mol.

In some embodiments of the invention, the water-soluble phenolic resin, polyethyleneimine and polypropyleneimine are commercially available, for example, the water-soluble phenolic resin is available from victory oil field services limited, and the polyethyleneimine and polypropyleneimine are available from mclin agents; can also be prepared by various methods known to those skilled in the art, and the preparation method can be known to those skilled in the art and will not be described herein again.

The inventor of the present invention found that in a preferred case, in the mussel biomimetic gel composition, when the degree of hydrolysis of the mussel biomimetic copolymer is 10-18 mol%, the weight average molecular weight is 800-900 ten thousand g/mol, and the complete dissolution time is less than 1.5 h; in the mussel bionic compound, the total weight of the mussel bionic compound is taken as a reference, the content of polyacrylamide is 75-80 wt%, the content of mussel bionic catechol compounds is 20-25 wt%, wherein the hydrolysis degree of polyacrylamide is 5-17 mol%, the weight average molecular weight is 800-1200 ten thousand g/mol, and the complete dissolution time is less than 1.5 h; the cross-linking agent is selected from water-soluble phenolic resin and/or polyethyleneimine, wherein the weight-average molecular weight of the water-soluble phenolic resin is 5000-30000g/mol, and the weight-average molecular weight of the polyethyleneimine is 1500-10000 g/mol; and the using amount of the mussel bionic copolymer is 0.25-0.4 weight part, the using amount of the mussel bionic compound is 0.25-0.4 weight part, the using amount of the cross-linking agent is 0.8-1.2 weight parts, and the using amount of the water is 98.4-98.95 weight parts, so that the system viscosity of the plugging agent after aging at the simulated formation temperature and the mineralization degree can be particularly improved, the aggregation self-growth effect of gel particles in the plugging agent can be enhanced, and the improvement of the injection performance, the shear repair performance and the migration capacity in cracks of the plugging agent is greatly facilitated.

In a second aspect, the invention provides a self-healing gel, which is formed by aging a composition comprising a mussel biomimetic copolymer and/or a mussel biomimetic complex, a cross-linking agent and water to form a gel; wherein the mussel biomimetic copolymer comprises structural units A from vinyl monomers and structural units B from vinyl-containing mussel biomimetic catechol radical monomers; the mussel bionic compound comprises polyacrylamide and mussel bionic catechol compounds. The kinds and amounts of the components in the composition can be reasonably selected according to the above description, and will not be described herein again.

In some embodiments of the invention, preferably, the gel has a rheological elastic modulus of 3 to 15Pa and a viscous modulus of 1 to 3 Pa.

In some embodiments of the present invention, preferably, the aging gelling conditions comprise: the temperature is 60-90 ℃ and the time is 24-72 h.

The third aspect of the invention provides a preparation method of self-repairing gel, which comprises the following steps:

(1a) in the presence of an initiator and a chain transfer agent, carrying out copolymerization reaction on a vinyl monomer and a mussel bionic catechol group monomer containing vinyl to obtain a mussel bionic copolymer; and/or

(1b) Mixing the mussel bionic catechol compound aqueous solution with the polyacrylamide aqueous solution to obtain a mussel bionic compound;

(2) aging the mussel bionic copolymer and/or the mussel bionic compound and a cross-linking agent to form gel, thereby obtaining the self-repairing gel.

In some embodiments of the present invention, the vinyl monomer and the mussel biomimetic catechol-based monomer containing vinyl group can be selected according to the above, and will not be described herein again.

In some embodiments of the present invention, the mussel biomimetic catechol compound and the polyacrylamide may be selected from the above, and will not be described herein.

In some embodiments of the present invention, the cross-linking agent may be selected according to the above description, and will not be described herein again.

In some embodiments of the invention, the initiator may be an azo-type initiator. The azo-type initiator may be selected, for example, from one or more of dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azobisformamide, azobisisobutylimidazoline hydrochloride, azobisisobutyrocarboxamide, azobiscyclohexylcarbonitrile, azobiscyanovaleric acid, azobisdiisopropylimidazoline, azobisisobutyronitrile, azobisisovaleronitrile, and azobisisoheptonitrile, preferably, the initiator is selected from azobisisobutyramidine hydrochloride and/or azobisisobutylimidazoline hydrochloride.

In some embodiments of the invention, the chain transfer agent is selected from one or more of water soluble dithiocarbonates, water soluble xanthates and water soluble trithiocarbonates, preferably water soluble xanthates and/or water soluble trithiocarbonates.

In some embodiments of the present invention, in step (1a), the weight ratio of the vinyl monomer, the mussel biomimetic catechol-based monomer containing a vinyl group, the initiator, and the chain transfer agent is 61-76: 7-12: 0.08-0.15: 0.2-0.5.

In some embodiments of the present invention, preferably, the mussel biomimetic copolymer has a degree of hydrolysis of 5 to 28 mol%, more preferably 10 to 18 mol%; the weight average molecular weight is 700-1000 ten thousand g/mol, more preferably 800-900 ten thousand g/mol; the complete dissolution time is less than 1.5 h.

In some embodiments of the present invention, in step (1a), the copolymerization reaction is generally carried out under an inert atmosphere, which may be, for example, one or more of nitrogen, helium, neon, argon.

In some embodiments of the present invention, it is preferred that the temperature of the copolymerization reaction is 55 to 70 ℃ and the time is 4 to 8 hours.

In some embodiments of the invention, in step (1b), the weight ratio of the mussel biomimetic catechol compound to polyacrylamide is 5-10: 25-30.

In some embodiments of the present invention, it is preferred that the polyacrylamide has a degree of hydrolysis of 5 to 28 mol%, more preferably 5 to 17 mol%; the weight average molecular weight is 700-1500 ten thousand g/mol, more preferably 800-1200 ten thousand g/mol; the complete dissolution time is less than 1.5 h.

In some embodiments of the present invention, in order to make the composite system of the two compounds more stable and the crosslinking reaction rate controllable, preferably, the mussel biomimetic catechol compound is further subjected to 10 to 40 mol% oxidative modification before the composite, and the oxidative modification is specifically: adjusting pH value (about 5-6) of the mussel biomimetic catechol compound to weak alkalinity (about 8-9) by using pH regulator, wherein the pH regulator can be NaOH or Na₂CO₃、NaHCO₃One or more of ethanolamine, polyetheramine, polyimine and polyamide, preferably the polyetheramine, polyimine and polyamide have a number average molecular weight of less than 5000 g/mol.

In some embodiments of the invention, in step (2), the weight ratio of the mussel biomimetic copolymer and/or the mussel biomimetic complex to cross-linking agent is from 0.2 to 0.5: 6-1.2.

In some embodiments of the present invention, preferably, in step (2), the temperature for forming the gel is 60-90 ℃ and the time is 24-72 h.

In a fourth aspect, the invention provides a self-healing gel prepared by the above method.

In some embodiments of the present invention, preferably, the self-healing gel has a rheological elastic modulus of 3 to 15Pa and a viscous modulus of 1 to 3 Pa. The self-repairing gel is formed by chemical crosslinking and non-covalent crosslinking, has adhesion to a rock wall surface, and has cohesiveness and self-repairing property.

The invention provides a self-growing gel particle profile control agent, which is formed by blending and shearing self-repairing gel and water.

In some embodiments of the present invention, preferably, the weight ratio of the self-repairing gel to water is 1-2: 0.5-6.

In some embodiments of the invention, the water blended with the self-healing gel may be purified water, tap water, and water having a degree of formation mineralization (< 150000 mg/L).

In some embodiments of the present invention, the blending shear may be performed by methods conventional in the art, so long as the desired particle size of the profile control agent is achieved. The blend of self-healing gel and water may be mechanically sheared, for example, using a homogenizer, masher, and mechanical mill.

In some embodiments of the present invention, it is preferable that the primary particle size of the plugging agent is 200-5000nm and the apparent viscosity is 3-15 mPas.

The invention provides an application of the self-growing gel particle plugging agent in a low-permeability fractured reservoir.

The self-growing gel particle plugging agent can be stably dispersed in a room temperature environment, has low initial apparent viscosity (3-15mPa & s), is easy to inject and far migrate, is not easy to block a stratum near a well, is not influenced by shearing in the injection and migration processes, can realize self-repairing after the blocky gel in the plugging agent is damaged in the environment of stratum mineralization degree (less than or equal to 150000mg/L) and stratum temperature (less than or equal to 110 ℃), can be crosslinked again among gel particles, has aggregation repair self-growth, is gradually adsorbed on the surface of rock, increases the particle size of the gel particles along with the breakage of the gel particles, has good shearing repair performance, is particularly suitable for low-permeability fractured oil reservoirs, adjusts a micro-fractured network, improves fractured flow channels, improves water flooding efficiency and improves recovery ratio.

The present invention will be described in detail by way of examples, but it should be understood that the scope of the present invention is not limited by the examples.

In the following examples and comparative examples, unless otherwise specified, the starting materials, reagents and the like used were commercial products in which:

polyacrylamide (5 mol% hydrolysis, weight average molecular weight 1200 ten thousand g/mol; 17 mol% hydrolysis, 1200 ten thousand g/mol; 25 mol% hydrolysis, 1000 ten thousand g/mol; 36 mol% hydrolysis, 500 ten thousand g/mol) was purchased from mclin reagents;

polyethyleneimine (weight average molecular weight 1500g/mol) was purchased from Michael reagent, Inc.;

water-soluble phenolic resin (weight average molecular weight 26000g/mol) purchased from Shengli oilfield services, Inc.;

the trithiocarbonate is self-made in a laboratory, and the specific preparation method is as follows:

adding potassium ethyl xanthate and 2-bromomethyl propionate into a flask according to the molar ratio of 1.2:1, reacting for 18 hours at 25 ℃ by using methanol as a solvent, performing rotary evaporation to remove the solvent, and extracting and drying by ethyl acetate to obtain trithiocarbonate.

The test methods involved in the examples and comparative examples are as follows:

(1) degree of hydrolysis test

The degree of hydrolysis of the polymer is tested by adopting the oil and gas industry standard SY/T5862-.

(2) Molecular weight measurement

Adopting a US Waters 2695GPC gel chromatograph, setting the column temperature at 25 ℃, and setting the mobile phase NaNO₃And a pretreatment process: and (2) ultrasonically degassing the prepared filter membrane, weighing 0.03-0.05g of polymer sample, dissolving the polymer sample into 100mL of mobile phase, sampling 100 mu L of the polymer sample, filtering and loading the polymer sample on a machine, and performing data processing by a GPC/SEC calibration method to obtain the molecular weight and the distribution of the molecular weight.

(3) Particle size distribution test

The Marwen Zetasizer Nano laser particle analyzer is adopted, the instrument is preheated for 20-30 minutes after being started, a circulating sample injector switch is turned on, centering correction is carried out on the laser particle analyzer, and then a sample is prepared after the temperature is set to be 25 ℃. Preparing a sample into 2-10% dispersion, adding 15-20mL of the dispersion into a container of an instrument for testing, and analyzing a picture by using Zetasizer nano software carried by the instrument to obtain a particle size distribution map.

(4) Rheological viscoelasticity modulus test and rheological self-repairing performance test

The linear viscoelastic region was first determined using the HaaKe RS60 rheometry followed by a viscoelastic test lasting 300s and the storage (G') and loss (G ") moduli were recorded. Placing the self-repairing gel on a rheometer flat plate, setting the temperature to be 25 ℃, firstly scanning to determine a linear viscoelastic region, gradually increasing a strain value until the gel is damaged, repeating the steps after staying for 3-10min, preliminarily judging the self-recovery performance of the gel, then carrying out a strain oscillation self-repairing test, determining the temperature and angular frequency, and carrying out 3 times of cyclic oscillation scanning on the strain values before and after the damage point.

(5) Viscosity measurement

The apparent viscosity was obtained by direct testing by pouring the aqueous gel particle solution into a cylindrical container using a brookfield-DV2D viscometer with a set temperature of 25 deg.C and a shear rate of 6 rpm.

Example 1

(1) Preparation of mussel biomimetic copolymer

Under the condition of room temperature, firstly adding 6.3g of acrylamide and 0.6g of acrylic acid into 25g of deionized water, stirring for 25min by introducing nitrogen, adding 0.8g of 3-acrylamide dopamine monomer, dissolving uniformly, adding 0.008g of azodiisobutylamine hydrochloride and 0.02g of water-soluble xanthate, carrying out water bath reaction for 6h at the temperature of 65 ℃, washing with ethanol, drying in a 40 ℃ oven, and crushing and granulating to obtain the white or grey mussel bionic copolymer.

The degree of hydrolysis of the mussel biomimetic copolymer is 10 mol%, and the gel chromatography analysis is performed on the mussel biomimetic copolymer, and the result is shown in fig. 1, and as can be seen from fig. 1, the weight average molecular weight of the mussel biomimetic copolymer is 800 ten thousand g/mol.

(2) Preparation of self-repairing gel

And (2) adding 0.4 part by weight of the mussel biomimetic copolymer prepared in the step (1) into 98.6 parts by weight of deionized water to prepare a solution, then adding 1 part by weight of water-soluble phenolic resin, uniformly stirring, sealing, and aging in an oven at 80 ℃ for 60 hours to obtain the self-repairing gel.

The rheological viscoelasticity modulus test is carried out on the self-repairing gel, the result is shown in figure 2, and as can be seen from figure 2, the rheological elasticity modulus of the self-repairing gel is 5.5-5.6Pa, and the viscous modulus is 1.8-1.9 Pa.

Rheological self-repairing performance tests are carried out on the self-repairing gel, and the results are shown in figure 3. As can be seen from fig. 3, in the rheological self-repair performance test, the oscillation strain of the self-repair gel is 10% and 1000%, and the modulus repair can be realized by circulating twice, which indicates that the self-repair gel prepared in this embodiment 1 has good self-repair performance.

(3) Preparation of self-growing gel particle plugging agent

Under the condition of room temperature, mixing the self-repairing gel obtained in the step (2) with tap water (the mineralization degree is 400-: 1, adding the mixture into a mechanical pounder, shearing the mixture for 12min at a constant speed of 8500rpm to obtain the self-growing gel particle plugging agent, and performing a particle size distribution test on the self-growing gel particle plugging agent, wherein the result is shown in a figure 4. As can be seen from FIG. 4, the particle size distribution of the plugging agent is unimodal, the relatively uniform median is about 650nm, and the primary particle size is 200-2000 nm. And performing viscosity test on the plugging agent to obtain the initial apparent viscosity of the plugging agent of 11.2 mPas.

Example 2

(1) Preparation of mussel bionic compound

At room temperature, firstly adding 0.2g of tannic acid into 15g of deionized water, stirring for dissolving, and then dropwise adding 1mL of polyether amine with the concentration of 10 wt% for adjusting the pH value of the solution to 8.6 to obtain a solution A1; preparing 250mL of 0.4 wt% solution B1 from polyacrylamide, and mixing the solution A1 and the solution B1 to obtain the mussel biomimetic composite.

Wherein the hydrolysis degree of the polyacrylamide is 5 mol%, and the weight average molecular weight is 1200 ten thousand g/mol.

(2) Preparation of self-repairing gel

And (2) adding 0.7 part by weight of polyethyleneimine into the mussel bionic compound obtained in the step (1), uniformly stirring, sealing, and aging in a 90 ℃ oven for 36 hours to obtain the self-repairing gel.

And performing rheological viscoelasticity modulus test on the self-repairing gel to obtain the self-repairing gel with rheological elasticity modulus of 3.6-3.8Pa and viscous modulus of 1.3-1.4 Pa.

Rheological self-repairing performance tests are carried out on the self-repairing gel, and the results are shown in figure 5. As can be seen from fig. 5, in the rheological self-repair performance test, the oscillation strain of the self-repair gel is 10% and 1000%, and the modulus repair can be realized by circulating twice, which indicates that the self-repair gel prepared in this embodiment 2 has good self-repair performance.

(3) Preparation of self-growing gel particle plugging agent

And (3) mixing the self-repairing gel obtained in the step (2) with tap water at room temperature according to the ratio of 2:1, adding the mixture into a homogenizer, and shearing the mixture at a constant speed of 12000rpm for 6min to obtain the self-growing gel particle plugging agent, and performing a particle size distribution test on the self-growing gel particle plugging agent, wherein the result is shown in figure 6. As can be seen from FIG. 6, the particle size distribution of the plugging agent is unimodal, the relatively uniform median is about 1000nm, and the primary particle size is 400-3000 nm. And performing viscosity test on the plugging agent to obtain the initial apparent viscosity of the plugging agent of 14.8 mPas.

Example 3

(1) Preparation of mussel biomimetic copolymer

At room temperature, adding 12g of acrylamide and 3g of acrylic acid into 60g of deionized water, introducing nitrogen, stirring for 20min, adding 2.3g of 3-methylacrylamidodopamine monomer, dissolving uniformly, adding 0.018g of azobisisobutyronitrile hydrochloride and 0.05g of water-soluble trithiocarbonate, carrying out water bath reaction at 50 ℃ for 8h, washing with ethanol, drying in a 40 ℃ oven, and crushing and granulating to obtain the white or off-white mussel bionic copolymer.

The mussel bionic copolymer has a hydrolysis degree of 18 mol% and a weight average molecular weight of 900 ten thousand g/mol.

(2) Preparation of self-repairing gel

And (2) adding 0.3 part by weight of the mussel biomimetic copolymer prepared in the step (1) into 98.9 parts by weight of deionized water to prepare a solution, then adding 0.8 part by weight of polyethyleneimine, uniformly stirring, sealing, and aging in a 90 ℃ oven for 40h to obtain the self-repairing gel.

And performing rheological viscoelasticity modulus test on the self-repairing gel to obtain the self-repairing gel with rheological elasticity modulus of 5.6-5.8Pa and viscous modulus of 1.8-1.9 Pa.

The self-repairing gel is subjected to rheological self-repairing performance test, in the rheological self-repairing performance test, the modulus repair can be realized by circulating the self-repairing gel twice, and the self-repairing gel prepared in the embodiment 3 also has good self-repairing performance.

(3) Preparation of self-growing gel particle plugging agent

Preparing mineralization water (5000mg/L NaCl; 300mg/L CaCl)₂；200mg/L MgCl₂) And then, under the condition of room temperature, mixing the self-repairing gel obtained in the step (2) with prepared mineralization water according to the ratio of 2:1, adding the mixture into a mechanical pounding machine, shearing the mixture for 15min at a constant speed at a rotating speed of 10000rpm to obtain a self-growing gel particle plugging agent, and performing a particle size distribution test on the self-growing gel particle plugging agent to obtain an initial particle with a particle size of 600-2000 nm; and performing viscosity test on the plugging agent to obtain the initial apparent viscosity of the plugging agent of 14.2 mPas.

The plugging agent seals were aged at different temperatures and after 15 days the viscosity and particle size distribution at different temperatures were tested and the results are shown in tables 1 and 2. As can be seen from tables 1 and 2, the initial viscosity of the profile control and plugging agent is small, the viscosity of the profile control and plugging agent system is obviously increased under the temperature condition of 80-90 ℃, and the aggregation growth effect of gel particles in the profile control and plugging agent is obvious under the condition of simulating the mineralization degree of the stratum temperature.

Example 4

(1) Preparation of mussel bionic compound

At room temperature, firstly adding 0.3g of dopamine into 15g of deionized water, stirring for dissolving, and then dropwise adding 1mL of 10 wt% NaOH to adjust the pH value of the solution to 9, thereby obtaining a solution A2; preparing 250mL of 0.3 wt% solution B2 from polyacrylamide, and mixing the solution A2 and the solution B2 to obtain a mussel biomimetic compound;

wherein the hydrolysis degree of the polyacrylamide is 17 mol%, and the weight average molecular weight is 1200 ten thousand g/mol.

(2) Preparation of self-repairing gel

And (2) adding 1.0 part by weight of water-soluble phenolic resin into the mussel bionic compound obtained in the step (1), uniformly stirring, sealing, and aging in an oven at 80 ℃ for 60 hours to obtain the self-repairing gel.

And performing rheological viscoelasticity modulus test on the self-repairing gel to obtain the self-repairing gel with rheological elasticity modulus of 9.4-9.5Pa and viscous modulus of 2.1-2.2 Pa.

The self-repairing gel is subjected to rheological self-repairing performance test, in the rheological self-repairing performance test, the modulus repair can be realized by circulating the self-repairing gel twice, and the self-repairing gel prepared in the embodiment 4 also has good self-repairing performance.

(3) Preparation of self-growing gel particle plugging agent

Preparing water with mineralization degree (120000mg/L NaCl; 700mg/L CaCl)₂；600mg/L MgCl₂) And then, under the condition of room temperature, mixing the self-repairing gel obtained in the step (2) with the prepared mineralization water according to the ratio of 1: 2, adding the mixture into a homogenizer, shearing the mixture for 8min at a constant speed of 10000rpm to obtain a self-growing gel particle plugging agent, and performing particle size distribution test on the self-growing gel particle plugging agent to obtain an initial particle with the particle size of 800-3500 nm; and performing viscosity test on the plugging agent to obtain the initial apparent viscosity of the plugging agent of 5.8 mPas.

The profile control agent was aged at different temperatures and tested for viscosity and particle size distribution after 7 days at different temperatures, the results are shown in tables 1 and 2. As can be seen from tables 1 and 2, the initial viscosity of the plugging agent is small, the viscosity of the plugging agent system is obviously changed at the temperature of 80-90 ℃, and gel particles in the plugging agent also have aggregation growth behavior under the environment of simulating the temperature and the mineralization degree of a stratum.

Example 5

Following the procedure of example 3, except that the mussel biomimetic copolymer was prepared as follows:

at room temperature, adding 15g of acrylamide and 4g of acrylic acid into 70g of deionized water, introducing nitrogen, stirring for 20min, adding 2.8g of 3-methacrylamide dopamine monomer, dissolving uniformly, adding 0.02g of azobisisobutyronitrile hydrochloride and 0.08g of water-soluble trithiocarbonate, carrying out water bath reaction at 50 ℃ for 8h, washing with ethanol, drying in a 40 ℃ oven, and crushing and granulating to obtain the white or grey-white mussel bionic copolymer.

The mussel bionic copolymer has a hydrolysis degree of 21 mol% and a weight average molecular weight of 750 ten thousand g/mol.

The self-growing gel particle profile control agent prepared in example 5 was subjected to a viscosity test to obtain an initial apparent viscosity of 8.5 mPa-s.

Example 6

Following the procedure of example 3, except that the mussel biomimetic copolymer was prepared as follows:

at room temperature, adding 24g of acrylamide and 0.8g of acrylic acid into 80g of deionized water, stirring for 20min by introducing nitrogen, adding 2.6g of 3-methacrylamide dopamine monomer, dissolving uniformly, adding 0.04g of azobisisobutyrimidazoline hydrochloride and 0.09g of water-soluble trithiocarbonate, carrying out water bath reaction for 6h at 50 ℃, washing with ethanol, drying in a 40 ℃ oven, and crushing and granulating to obtain the white or grey mussel bionic copolymer.

The mussel bionic copolymer has a hydrolysis degree of 3 mol% and a weight average molecular weight of 580 ten thousand g/mol.

The self-growing gel particle profile control agent prepared in example 6 was subjected to a viscosity test to obtain an initial apparent viscosity of 13.6 mPa-s.

Example 7

The procedure of example 4 was followed except that the polyacrylamide had a degree of hydrolysis of 25 mol% and a weight average molecular weight of 1000 ten thousand g/mol.

The self-growing gel particle profile control agent prepared in example 7 was subjected to a viscosity test to obtain an initial apparent viscosity of 8.5 mPa-s.

Example 8

The procedure of example 4 was followed except that the polyacrylamide had a degree of hydrolysis of 36 mol% and a weight average molecular weight of 500 kg/mol.

The self-growing gel particle profile control agent prepared in example 8 was subjected to a viscosity test to obtain an initial apparent viscosity of 8.3 mPa-s.

Example 9

The procedure of example 3 was followed except that the mussel biomimetic copolymer was used in an amount of 0.2 parts by weight.

The self-growing gel particle profile control agent prepared in example 9 was subjected to a viscosity test to obtain an initial apparent viscosity of 6.7 mPa-s.

Example 10

The procedure of example 3 was followed except that the mussel biomimetic copolymer was used in an amount of 0.1 parts by weight.

The self-growing gel particle profile control agent prepared in example 10 was subjected to a viscosity test to obtain an initial apparent viscosity of 3.1 mPa-s.

Example 11

The method of example 4 was followed except that the mussel biomimetic composite was used in an amount of 0.6 parts by weight.

The self-growing gel particle plugging agent prepared in example 11 was subjected to a viscosity test to obtain an initial apparent viscosity of 6.2 mPa-s.

Example 12

The method of example 4 was followed except that the mussel biomimetic composite was used in an amount of 0.7 parts by weight.

The self-growing gel particle profile control agent prepared in example 12 was subjected to a viscosity test to obtain an initial apparent viscosity of 7.3 mPa-s.

Example 13

According to the method of example 4, except that the mussel biomimetic complex is prepared as follows:

at room temperature, firstly adding 0.3g of dopamine into 15g of deionized water, and stirring for dissolving to obtain a solution A2; preparing 250mL of 0.3 wt% solution B2 from polyacrylamide, and mixing the solution A2 and the solution B2 to obtain the mussel biomimetic composite.

The self-growing gel particle profile control agent prepared in example 13 was subjected to a viscosity test to obtain an initial apparent viscosity of 6.5 mPa-s.

Comparative example 1

The procedure of example 1 was followed except that 3-acrylamidodopamine monomer was not added in step (1).

The plugging agent prepared in comparative example 1 was subjected to a viscosity test to obtain an initial apparent viscosity of 9.5 mPa-s.

The self-growing gel particle size closures prepared in examples 5-13 and comparative example 1 were aged at different temperatures and tested for viscosity and particle size distribution after 15 days at different temperatures, and the results are shown in tables 1 and 2.

TABLE 1 System viscosity (mPa. s) of self-growing gel particle profile control agent at different temperatures

Numbering	70℃	80℃	90℃	100℃
					Example 3	45.5	55.6	58.3	47.8
Example 4	28.7	35.2	36.7	25.2
					Example 5	36.4	46.5	48.2	35.1
Example 6	18.6	21.2	20.6	15.2
					Example 7	26.3	31.2	32.4	25.8
Example 8	17.7	19.6	20.1	15.5
					Example 9	32.3	45.7	44.6	43.8
Example 10	14.5	15.2	15.0	15.4
					Example 11	23.1	28.6	30.5	22.8
Example 12	17.5	19.3	18.6	18.4
					Example 13	22.8	26.5	28.9	21.2
Comparative example 1	12.7	13.2	13.7	11.2

TABLE 2 particle size distribution (nm) of self-growing gel particle profile control agent at different temperatures

Numbering	70℃	80℃	90℃	100℃
					Example 3	1500-42000	2000-78000	1800-62000	1600-50000
Example 4	1800-27000	2200-56000	2000-45000	2000-42000
					Example 5	1600-36000	2200-66000	1800-54000	2000-48000
Example 6	1500-6000	1800-7500	1800-6600	2000-6000
					Example 7	1600-24000	2000-38000	1800-40000	2000-36000
Example 8	1800-8500	2000-9000	2000-8600	2200-8000
					Example 9	1600-26000	1800-52000	2000-50000	2000-48000
Example 10	1800-7000	2000-7000	2200-6500	2000-5500
					Example 11	2000-22000	2000-56000	2200-40000	2200-40000
Example 12	2000-12000	2000-20000	2200-24000	2200-18000
					Example 13	2200-20000	2200-45000	2000-40000	2200-36000
Comparative example 1	800-5000	1000-5500	1000-5000	900-4500

As can be seen from the results of the examples, the comparative examples and the tables 1-2, the self-repairing gel prepared from the mussel bionic gel composition has good shearing repairing performance, and the block-shaped gel can realize self-repairing after being damaged; the self-growing gel particle plugging agent prepared from the self-repairing gel has low initial apparent viscosity (3-15mPa & s), is easy to inject and move far, and is not easy to plug the stratum near the well; under the temperature condition of 80-90 ℃, the viscosity of the plugging agent system is obviously increased, and the gel particles in the plugging agent have obvious aggregation growth effect under the environment of simulating the formation temperature and the mineralization degree, so that the plugging agent is particularly suitable for low-permeability fractured reservoirs.

In examples 5 to 8, when the degree of hydrolysis and the weight average molecular weight of the mussel biomimetic copolymer and/or the degree of hydrolysis and the weight average molecular weight of the polyacrylamide in the mussel biomimetic composite are not preferred, the self-growing gel particle plugging agent prepared, after aging at a simulated formation temperature and mineralization, increases in system viscosity and the effect of aggregation growth of gel particles, without using the degree of hydrolysis and the weight average molecular weight well within the preferred ranges.

In examples 9-12, when no preference was given to using amounts of mussel biomimetic copolymer and/or mussel biomimetic complex, the gel particle plugging agent was prepared and self-grown, and the increase in viscosity of the system and the effect of aggregate growth of the gel particles after aging at simulated formation temperatures and mineralization did not appear to be as good as when using amounts in the preferred ranges.

In example 13, the self-repairing gel and self-growing gel particle plugging agent prepared without oxidative modification of the mussel biomimetic catechol compound has good effects of increasing the viscosity of the system and aggregating and growing gel particles after aging at simulated formation temperature and mineralization, and is not subjected to oxidative modification.

In the comparative example 1, the mussel bionic copolymer without the introduction of the catechol group is adopted to prepare the self-repairing gel and self-growing gel particle plugging agent, the increase of the system viscosity and the aggregation growth effect of gel particles are not obvious after aging at the simulated formation temperature and the mineralization degree, which indicates that the gel and the plugging agent with good injection performance and shear repair performance can not be obtained without the introduction of the catechol group.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.