A heat-resistant, salt-resistant and anti-swelling clay stabilizer and its preparation process and application

Abstract

The present invention provides a kind of heat-resistant and salt-resistant anti-swelling clay stabilizer and its preparation method and application, the present invention is by first reacting 2,3,6,7-naphthalenetetracarboxylic acid dianhydride with composite isomeric alcohol, carboxylic anhydride group ring-opening and isomeric alcohol hydroxyl reaction, then the carboxyl on the product reacts with dimethylamino chloroethane, connects dimethylaminoethyl, and finally reacts with bromine-containing heterocyclic compound, generates heterocyclic clay stabilizer. The clay stabilizer structure of the present invention contains high temperature resistant benzene ring and heterocyclic group, and introduces long-chain alkyl by composite isomeric alcohol, which helps to improve the thermal stability and salt tolerance of clay stabilizer, improves stabilizer to suppress clay hydration expansion rate and suppress shale hydration dispersion ability. The clay stabilizer of the present invention can keep stable and will not decompose under the conditions of 280 ℃ and mineralization degree of 230000mg / L, and can be applied to high temperature resistant clay stabilizer used for anti-swelling of high temperature and high salt reservoir in oil field development.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum development, and in particular relates to a temperature-resistant, salt-resistant and anti-swelling clay stabilizer and a preparation process and application thereof. Background Art

[0002] my country's high-temperature and high-salinity oil reservoir resources are widely distributed and rich in high-temperature and high-salinity oil reservoir resources. These oil reservoirs are usually located in areas with complex geological structures and harsh mining conditions. my country has shown strong technical driving force and innovation capabilities in the development and utilization of high-temperature and high-salinity oil reservoirs, but it also faces complex technical challenges. China's high-temperature and high-salinity oil reservoirs are mainly distributed in some specific geographical areas, which usually have the following characteristics: geothermal activity is relatively active, or they are in arid and semi-arid climate zones, and the groundwater circulation conditions are special, resulting in higher concentrations of minerals in the groundwater, especially chlorides and other salts.

[0003] Areas in China where high-temperature and high-salinity oil reservoirs are relatively concentrated: Dagang Oilfield: Located near Tianjin City, some of its oil reservoirs are of the high-temperature and high-salinity type, and it has successfully developed internationally leading high-temperature and high-salinity oil reservoirs to improve recovery. Shengli Oilfield: Located in the northern part of Shandong Province, it is one of China's important oil production bases. Shengli Oilfield also has high-temperature and high-salinity oil reservoirs, and has developed new polymer technology to break through the development restricted areas of such oil reservoirs. Zhongyuan Oilfield: Located in Henan Province, there are also research reports focusing on the development technology of its high-temperature and high-salinity oil reservoirs, such as the research on hydrophobic associating polymer gel profile control agents to improve mining efficiency. Shengtuo Oilfield: Also within the scope of Shengli Oilfield, for its high-temperature and high-salinity oil reservoirs, some research focuses on chemical flooding technology to explore ways to improve recovery.

[0004] The reservoir characteristics in these areas require special exploration, development techniques and chemical treatment agents to cope with the challenges brought by high temperature and high salinity. With the advancement of technology, China has achieved remarkable results in the development of high-temperature and high-salinity reservoirs, and has continuously promoted the effective utilization of these difficult-to-extract resources. High-temperature and high-salinity reservoirs refer to a special geological condition encountered in oil production, in which the formation temperature is high and the formation water contains a high concentration of salt. The exploitation of such reservoirs faces many challenges, and the clay stability problem is just one of the difficulties. In a high-temperature and high-salinity environment, the clay minerals in the oil layer are prone to hydration and expansion, resulting in pore channel blockage, affecting the flow and production of crude oil. Therefore, it is necessary to use a clay stabilizer with strong high-temperature and salt resistance to control clay expansion and protect the permeability of the oil layer.

[0005] The formation contains clay minerals such as kaolinite, montmorillonite, illite and chlorite. During the development of oil fields, foreign fluids (water) come into contact with clay minerals in the formation and can enter between the crystal layers of clay minerals. The exchangeable cations on the surface of the crystal layer dissociate and diffuse in the water to form a diffuse double layer, which makes the surface charged. The crystal layers repel and expand each other. Clay expansion can cause the formation permeability to decrease. In order to reduce damage to the reservoir, clay stabilizers are used to stabilize the clay minerals in the formation.

[0006] High temperature and high salt environment places extremely high demands on the chemical stability and thermal stability of clay stabilizers. Clay stabilizers need to be effective under high temperature (usually over 150°C, even up to 280°C) and high salinity (salt concentration can exceed 230,000 mg / L) conditions, and not easily degraded or lose function. However, the clay stabilizers currently on the market are difficult to maintain good effects under the above conditions and cannot effectively inhibit expansion. Summary of the invention

[0007] The purpose of the present invention is to provide a preparation process and application of a heat-resistant, salt-resistant and anti-swelling clay stabilizer, which can remain stable and will not decompose under the conditions of 280°C and a mineralization degree of 230,000 mg / L, and can be used as a high-temperature resistant clay stabilizer for anti-swelling of high-temperature and high-salt oil reservoirs in oil field development.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A preparation process of a heat-resistant, salt-resistant and anti-swelling clay stabilizer, the preparation process comprising the following steps:

[0010] (1) Mixing 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3-1.5 mol of composite isomeric alcohol, heating to 86-88° C., reacting for 2-3 hours, adding n-heptane, reacting for 4-5 hours, and then cooling to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a compound of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.3-0.7:1.2-1.5;

[0011] (2) adding 1.3-1.5 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 6-7 hours, and then heating to 84-87° C. to react for 12-14 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0012] (3) Mixing the mixed solution B, 1.1-1.4 mol of the bromine-containing heterocyclic compound and butanone, reacting at 68-74° C. for 18-22 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0013] (4) The crude product is distilled under reduced pressure to remove the solvent, and passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, and then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0014] The present invention is to react 2,3,6,7-naphthalenetetracarboxylic acid dianhydride with a composite isomeric alcohol, open the carboxylic anhydride group and react with the hydroxyl group of the isomeric alcohol, then react the carboxyl group on the product with dimethylaminoethyl chloride, connect the dimethylaminoethyl, and finally react with a bromine-containing heterocyclic compound to generate a clay stabilizer containing a heterocycle. The structure of the present invention contains a high temperature resistant benzene ring and a heterocyclic group. The heterocyclic ring has greater rigidity and stronger intermolecular force than the carbon ring, which helps to improve the thermal stability of the clay stabilizer. At the same time, the introduction of heteroatoms can change the electronic distribution of the molecule, further enhance the interaction between molecules, and thus improve the temperature resistance. The inventors found that when a specific proportion of composite isomeric alcohols is used, the ability of the stabilizer to inhibit the hydration expansion rate of the clay and the ability to inhibit the hydration dispersion of shale can be improved.

[0015] Furthermore, the bromine-containing heterocyclic compound is selected from one or more of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine.

[0016] Furthermore, the bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.3-0.6:1.4-1.8.

[0017] Furthermore, the bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.4:1.6.

[0018] The clay anti-swelling stabilizer provided by the present invention improves the salt resistance of the clay stabilizer by using a specific proportion of bromine-containing heterocyclic compounds, and effectively improves the use efficiency. Analysis shows that heterocyclic structures usually have stronger intermolecular forces than simple carbon rings, such as hydrogen bonds, π-π stacking, etc., which helps the clay stabilizer to be more tightly adsorbed on the clay surface, forming a more stable protective layer to prevent clay hydration expansion and dispersion, thereby improving its stabilizing effect; the introduction of heterocyclic groups can enhance the hydrophobicity and charge shielding effect of the molecule, reduce the interference of salt on the adsorption of clay mineral surfaces, and thus improve the overall salt resistance.

[0019] Furthermore, the mass of the n-heptane is 20-22 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0020] Furthermore, the mass of the butanone is 30-33 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0021] Furthermore, in step (2), the mixture is dried with anhydrous magnesium sulfate for 20-25 hours.

[0022] Furthermore, in the step (2), the filter residue is washed 2-3 times with hot petroleum ether.

[0023] 2-(2-Bromoethyl)thiophene, CAS: 26478-16-0.

[0024] 2-(2-Bromoethyl)pyridine, CAS: 39232-04-7.

[0025] 2-Bromomethylfuran, CAS: 4437-18-7.

[0026] Dimethylaminoethyl chloride, CAS: 107-99-3.

[0027] Isotridecyl alcohol, CAS: 68526-86-3.

[0028] The invention provides a clay stabilizer prepared by the preparation process.

[0029] The invention also provides application of the clay stabilizer in oil field development.

[0030] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0031] 1. The present invention provides a heat-resistant, salt-resistant, anti-swelling clay stabilizer. The anti-swelling clay stabilizer contains a high-temperature-resistant benzene ring and a heterocyclic group in its structure. The heterocyclic ring has greater rigidity and stronger intermolecular forces than the carbon ring, which helps to improve the thermal stability of the clay stabilizer. At the same time, the introduction of heteroatoms can change the electronic distribution of the molecule, further enhance the interaction between molecules, and thus improve the temperature resistance. The inventors found that when a specific proportion of composite isomeric alcohols is used, the ability of the stabilizer to inhibit the hydration expansion rate of clay and the hydration dispersion of shale can be improved.

[0032] 2. The clay anti-swelling stabilizer provided by the present invention improves the salt resistance of the clay stabilizer by using a specific proportion of bromine-containing heterocyclic compounds, and effectively improves the use efficiency. The clay stabilizer of the present invention can remain stable and will not decompose under the conditions of 280°C and a mineralization degree of 230000 mg / L, and can be used as a high-temperature resistant clay stabilizer used for anti-swelling of high-temperature and high-salinity oil reservoirs in oil field development. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0036] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.4 mol of composite isomeric alcohol are mixed, the temperature is raised to 87° C., the reaction is carried out for 2.5 hours, n-heptane is added, the reaction is carried out for 4.5 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.5:1.3;

[0037] (2) adding 1.4 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 6.5 hours, and then heating to 85° C. to react for 13 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0038] (3) Mixing the mixed solution B, 1.2 mol of the bromine-containing heterocyclic compound and butanone, reacting at 70° C. for 20 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0039] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0040] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.4:1.6.

[0041] The mass of the n-heptane is 21 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0042] The mass of the butanone is 32 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0043] In the step (2), the mixture is dried with anhydrous magnesium sulfate for 22 hours.

[0044] In the step (2), the filter residue is washed with hot petroleum ether for 3 times.

[0045] Example 2

[0046] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0047] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3 mol of composite isomeric alcohol are mixed, the temperature is raised to 86° C., the reaction is carried out for 2 hours, n-heptane is added, the reaction is carried out for 4 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.3:1.2;

[0048] (2) adding 1.3 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 6 h, and then heating to 84° C. to react for 12 h; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0049] (3) Mixing the mixed solution B, 1.1 mol of the bromine-containing heterocyclic compound and butanone, reacting at 68° C. for 18 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0050] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0051] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.3:1.4.

[0052] The mass of the n-heptane is 20 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0053] The mass of the butanone is 30 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0054] In the step (2), the mixture is dried with anhydrous magnesium sulfate for 20 hours.

[0055] In the step (2), the filter residue is washed twice with hot petroleum ether.

[0056] Example 3

[0057] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0058] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.5 mol of composite isomeric alcohol are mixed, the temperature is raised to 88° C., the reaction is carried out for 3 hours, n-heptane is added, the reaction is carried out for 5 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.7:1.5;

[0059] (2) adding 1.5 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 7 hours, and then heating to 87° C. to react for 14 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0060] (3) Mixing the mixed solution B, 1.4 mol of the bromine-containing heterocyclic compound and butanone, reacting at 74° C. for 22 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0061] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0062] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.6:1.8.

[0063] The mass of the n-heptane is 22 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0064] The mass of the butanone is 33 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0065] In the step (2), the product is dried with anhydrous magnesium sulfate for 25 hours.

[0066] In the step (2), the filter residue is washed with hot petroleum ether for 3 times.

[0067] Example 4

[0068] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0069] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3 mol of composite isomeric alcohol are mixed, the temperature is raised to 86° C., the reaction is carried out for 2 hours, n-heptane is added, the reaction is carried out for 4 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.3:1.2;

[0070] (2) adding 1.3 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 6 h, and then heating to 84° C. to react for 12 h; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0071] (3) Mixing the mixed solution B, 1.1 mol of the bromine-containing heterocyclic compound and butanone, reacting at 68° C. for 18 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0072] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0073] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.3:1.4.

[0074] The mass of the n-heptane is 20 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0075] The mass of the butanone is 30 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0076] In the step (2), the mixture is dried with anhydrous magnesium sulfate for 20 hours.

[0077] In the step (2), the filter residue is washed twice with hot petroleum ether.

[0078] Example 5

[0079] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0080] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.4 mol of composite isomeric alcohol are mixed, the temperature is raised to 88° C., the reaction is carried out for 2 hours, n-heptane is added, the reaction is carried out for 5 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.4:1.4;

[0081] (2) adding 1.3 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 7 hours, and then heating to 84° C. to react for 14 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0082] (3) Mixing the mixed solution B, 1.1 mol of the bromine-containing heterocyclic compound and butanone, reacting at 74° C. for 18 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0083] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0084] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.5:1.2.

[0085] The mass of the n-heptane is 22 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0086] The mass of the butanone is 30 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0087] In the step (2), the product is dried with anhydrous magnesium sulfate for 25 hours.

[0088] In the step (2), the filter residue is washed twice with hot petroleum ether.

[0089] Example 6

[0090] This embodiment provides a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, and the preparation process of the clay stabilizer comprises the following steps:

[0091] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3 mol of composite isomeric alcohol are mixed, heated to 88°C, reacted for 2 hours, n-heptane is added, reacted for 5 hours, and then cooled to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.3:1.5;

[0092] (2) adding 1.3 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 7 hours, and then heating to 84° C. to react for 14 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0093] (3) Mixing the mixed solution B, 1.1 mol of the bromine-containing heterocyclic compound and butanone, reacting at 74° C. for 18 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0094] (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0095] The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.6:1.4.

[0096] The mass of the n-heptane is 22 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0097] The mass of the butanone is 30 times that of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0098] In the step (2), the product is dried with anhydrous magnesium sulfate for 25 hours.

[0099] In the step (2), the filter residue is washed twice with hot petroleum ether.

[0100] Example 7

[0101] This embodiment provides a preparation process of a temperature-resistant, salt-resistant and anti-swelling clay stabilizer, the preparation process comprising the following steps:

[0102] (1) 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3 mol of composite isomeric alcohol are mixed, the temperature is raised to 87° C., the reaction is carried out for 2.2 hours, n-heptane is added, the reaction is carried out for 4.8 hours, and then the temperature is lowered to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.4:1.3;

[0103] (2) adding 1.3 mol of dimethylaminoethyl chloride to the mixed solution A, reacting at room temperature for 6.7 hours, and then heating to 85° C. to react for 12 hours; filtering to obtain a filter residue, washing the filter residue, collecting the filtrate, drying, and removing n-heptane under reduced pressure to obtain a mixed solution B;

[0104] (3) Mixing the mixed solution B, 1.1 mol of the bromine-containing heterocyclic compound and butanone, reacting at 69° C. for 19 h under a nitrogen atmosphere, and cooling to room temperature to obtain a crude product;

[0105] (4) The crude product is distilled under reduced pressure to remove the solvent, and passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, and then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer.

[0106] Furthermore, the bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.3:1.7.

[0107] Furthermore, the mass of the n-heptane is 21 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0108] Furthermore, the mass of the butanone is 30 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

[0109] Furthermore, in step (2), the mixture is dried with anhydrous magnesium sulfate for 24 hours.

[0110] Furthermore, in the step (2), the filter residue is washed with hot petroleum ether for 3 times.

[0111] Comparative Example 1

[0112] The difference between this comparative example and Example 1 is that the composite isomeric alcohol is a compound of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:1:1.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that the composite isomeric alcohol is a compound of n-dodecanol, n-tridecanol and 1-pentadecanol in a mass ratio of 1:0.5:1.3.

[0115] Comparative Example 3

[0116] The difference between this comparative example and Example 1 is that the composite isomeric alcohol is a compound of isotridecanol, n-tridecanol and 6-undecanol in a mass ratio of 1:0.5:1.3.

[0117] Comparative Example 4

[0118] The difference between this comparative example and Example 1 is that the bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:1:1.

[0119] Comparative Example 5

[0120] The difference between this comparative example and Example 1 is that the bromine-containing heterocyclic compound is replaced by 2-bromomethylpyridine.

[0121] Comparative Example 6

[0122] The difference between this comparative example and Example 1 is that the bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene and 2-(2-bromoethyl)pyridine in a mass ratio of 1:1.6.

[0123] Performance Testing

[0124] Sample preparation: Weigh 5 g of the clay stabilizer prepared in Examples 1-7 and Comparative Examples 1-6, dissolve it in 995 g of distilled water, and stir evenly to obtain a sample.

[0125] 1. With reference to "SY / T5971-1994 Performance Evaluation Method of Clay Stabilizer for Water Injection", the anti-swelling rate of the product at a temperature of 280°C and a mineralization of 230,000 mg / L was evaluated.

[0126] 2. Refer to "SY-T5613-2000 Test Method for Physical and Chemical Properties of Shale" to evaluate the ability of clay stabilizer to inhibit shale hydration and dispersion.

[0127] The rock sample used is a rock chip from an oil field, which is washed with 3% hydrogen peroxide for 10 minutes and then dried. Then take 200mL of sample, add 50g of 20-30 mesh rock chips, heat roll at 280℃ for 24h, wash with clean water, pass through a 100-mesh sieve, dry at 280℃ for 6h, weigh, and get the mass after one rolling. Calculate the recovery rate of one rolling = mass after one rolling / mass before rolling (50g) × 100%.

[0128] 3. Carry out the linear expansion test of the sample in accordance with "SY / T6335-1997". The instrument used is NP-3 shale expansion tester. Weigh 5g of bentonite (diameter 0.01-0.05mm) dried at 280℃ for 10h, and make a tablet on a press (pressure 10MPa, time 5min). Put the tablet into the shale expansion instrument, add 200mL of sample, and measure the expansion rate of the mud shale tablet after immersion in the test solution for 16 hours, recorded as A1; among them, the smaller the expansion rate of the mud shale tablet, the stronger the ability of the product to inhibit clay hydration expansion; vice versa. Then replace the sample with water, carry out the same test, and obtain the expansion rate of the mud shale tablet after immersion in water for 16 hours, recorded as A0. Calculate the reduction ratio of the expansion rate of the shale tablet of the product of the present invention relative to water for 16 hours, which is called the reduction rate relative to water in 16 hours. The calculation formula is: reduction rate relative to water in 16 hours / % = (A0-A1) / A0×100%.

[0129] The specific test results are shown in Table 1.

[0130] Table 1 Performance test results

[0131]

[0132] It can be seen from Table 1 that the clay stabilizers of Examples 1-7 have an anti-swelling rate greater than 98.5% at 280° C. and a mineralization degree of 230,000 mg / L, with the highest reaching 99.4%.

[0133] The primary rolling recovery rates of the clay stabilizers of Examples 1-7 were all greater than 98.0%, with the highest reaching 98.9%, indicating that the clay stabilizer products prepared by the present invention still have a strong ability to inhibit shale hydration and dispersion after hot rolling at 280°C.

[0134] The reduction rates of the clay stabilizers of Examples 1-7 relative to clean water in 16 hours were all lower than 23%, with the lowest reaching 20.5%, indicating that the clay stabilizer product prepared by the present invention can effectively inhibit the hydration expansion of clay.

[0135] Comparative Examples 1-6 show that the performance of the clay stabilizer decreases when the composite isomeric alcohol and the bromine-containing heterocyclic compound are changed.

[0136] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A preparation process of a heat-resistant, salt-resistant and anti-swelling clay stabilizer, characterized in that: The preparation process comprises the following steps: (1) Mix 1 mol of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 1.3-1.5 mol of composite isomeric alcohol, heat to 86-88°C, react for 2-3 hours, add n-heptane, react for 4-5 hours, and then cool to room temperature to obtain a mixed solution A; the composite isomeric alcohol is a mixture of isotridecanol, decyltetradecanol and 6-undecanol in a mass ratio of 1:0.3-0.7:1.2-1.5; (2) Add 1.3-1.5 mol of dimethylaminoethyl chloride to the mixed solution A, react at room temperature for 6-7 hours, then heat to 84-87° C. and react for 12-14 hours; filter to obtain a filter residue, wash the filter residue, collect the filtrate, dry it, and remove the n-heptane under reduced pressure to obtain a mixed solution B; (3) Mix the mixed solution B, 1.1-1.4 mol of the bromine-containing heterocyclic compound and butanone, react at 68-74° C. for 18-22 h under a nitrogen atmosphere, and cool to room temperature to obtain a crude product; (4) The crude product is distilled under reduced pressure to remove the solvent, passed through a silica gel chromatography column, first eluted with petroleum ether and ether in a volume ratio of 9:1, then eluted with methanol, the eluate is collected, and the eluent is removed to obtain a clay stabilizer; The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.3-0.6:1.4-1.

8.

2. The preparation process of the heat-resistant, salt-resistant and anti-swelling clay stabilizer according to claim 1, characterized in that: The bromine-containing heterocyclic compound is a mixture of 2-(2-bromoethyl)thiophene, 2-bromomethylfuran and 2-(2-bromoethyl)pyridine in a mass ratio of 1:0.4:1.

6.

3. The preparation process of the heat-resistant, salt-resistant and anti-swelling clay stabilizer according to claim 1, characterized in that: The mass of the n-heptane is 20-22 times the mass of 2,3,6,7-naphthalenetetracarboxylic dianhydride.

4. The preparation process of the heat-resistant, salt-resistant and anti-swelling clay stabilizer according to claim 1, characterized in that: The mass of the butanone is 30-33 times that of the 2,3,6,7-naphthalenetetracarboxylic dianhydride.

5. The preparation process of the heat-resistant, salt-resistant and anti-swelling clay stabilizer according to claim 1, characterized in that: In the step (2), the mixture is dried with anhydrous magnesium sulfate for 20-25 hours.

6. The preparation process of the heat-resistant, salt-resistant and anti-swelling clay stabilizer according to claim 1, characterized in that: In the step (2), the filter residue is washed 2-3 times with hot petroleum ether.

7. A clay stabilizer obtained according to the preparation process according to any one of claims 1 to 6.

8. Use of the clay stabilizer according to claim 7 in oil field development.

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