Clay mineral surface hydration intercalation inhibitor for drilling fluid as well as preparation method and application of clay mineral surface hydration intercalation inhibitor

Abstract

The invention belongs to the field of drilling fluid inhibitors, and discloses a clay mineral surface hydration intercalation inhibitor for drilling fluid as well as a preparation method and application of the clay mineral surface hydration intercalation inhibitor, the intercalation inhibitor comprises a compound with the following structure shown in the formula A. The intercalation inhibitor can effectively solve the technical problem that an existing intercalation inhibitor cannot completely inhibit surface hydration of clay minerals.

Description

Technical Field

[0001] This invention belongs to the field of drilling fluid inhibitor technology, and relates to a clay mineral surface hydration intercalation inhibitor for drilling fluid, its preparation method, and its application. Background Technology

[0002] In oil and gas drilling, wellbore instability has long been a problem plaguing the industry, frequently leading to complex downhole accidents such as wellbore collapse, borehole narrowing, and stuck pipe, significantly increasing drilling time and costs. Statistics show that 75% of wellbore instability problems occur primarily in shale formations, especially water-sensitive formations. Shale formations have high clay mineral content, making them highly susceptible to hydration upon contact with external fluids, leading to wellbore instability. Oil-based drilling fluids, due to their excellent wellbore stability and strong inhibition capabilities, have been widely used in these formations in the past. However, oil-based drilling fluids pose serious environmental pollution problems, which are difficult and costly to treat. Therefore, developing water-based drilling fluids with comparable performance to oil-based fluids to replace them has become a current trend in drilling fluid technology development, which is particularly important in shale gas development. Shale gas horizontal wells have long horizontal sections, significantly increasing the contact time between the drilling fluid and the formation, exacerbating shale hydration problems and making wellbore instability more prominent.

[0003] For decades, researchers have dedicated themselves to solving the problem of clay swelling and have developed a variety of clay hydration inhibitors. Existing clay hydration inhibitors mainly include inorganic salts, formates, polymers, bitumen, sugars and their derivatives, glycerol, ethylene glycol, and silicates. For example, Chinese Patent Publication No. CN114395380A discloses a clay mineral surface hydration intercalation inhibitor, its preparation method, and its application. This inhibitor is a compound of formula (I):

[0004] However, while these inhibitors can suppress clay mineral hydration to some extent, their application in highly water-sensitive formations has not been entirely successful, failing to completely inhibit the surface hydration of clay minerals. Especially when clay minerals come into contact with external fluids, their surface hydration capacity is extremely strong, with hydration pressures reaching up to 400 MPa, making inhibition and removal extremely difficult. Furthermore, most of the polyamine inhibitors currently studied and applied are linear structures. For linear polyamine inhibitors, after dissolving in water, they typically exhibit an irregular linear configuration. When used in shale gas drilling, their entanglement and coating on clay are uneven, easily leading to repeated adsorption or no adsorption at all. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a clay mineral surface hydration intercalation inhibitor for drilling fluids, its preparation method, and its application, thereby solving the technical problem that existing clay hydration inhibitors cannot completely inhibit the surface hydration of clay minerals.

[0006] This invention is achieved through the following technical solution: A drilling fluid inhibitor for hydration intercalation of clay mineral surfaces, comprising compound A with the following structure: ; Where n1 and n2 are each independently selected from integers from 1 to 200; R1 is selected from substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C3-C16 cycloalkyl, substituted or unsubstituted C5-C14 aryl, substituted or unsubstituted 3-16 heterocyclic, or substituted or unsubstituted 5-14 heteroaryl. Ar1 is selected from substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C5-C14 aryl, substituted or unsubstituted 3-10 heterocyclic or substituted or unsubstituted 5-10 heteroaryl.

[0007] Preferably, R1 is selected from substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C2-C5 alkenyl, substituted or unsubstituted C2-C5 alkynyl, substituted or unsubstituted C1-C5 alkoxy, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C5-C12 aryl, substituted or unsubstituted 3-10 heterocyclic or substituted or unsubstituted 5-10 heteroaryl.

[0008] Preferably, R1 is selected from methyl, ethyl, or phenyl; the methyl, ethyl, or phenyl group is optionally substituted with one or more C1-C3 alkyl, amino, nitro, or hydroxyl groups.

[0009] Preferably, Ar1 is selected from substituted or unsubstituted C5-C14 aryl groups.

[0010] Preferably, Ar1 is selected from , or .

[0011] Preferably, n1 and n2 are each independently selected from integers from 10 to 150.

[0012] Preferably, the intercalation inhibitor comprises at least one of the following compounds: Formula A-1, Formula A-2, or Formula A-3: , , ; Preferably, the mass percentage of compound A is 0.5% to 5% based on the total mass of the intercalation inhibitor.

[0013] The above-mentioned method for preparing the clay mineral surface hydration intercalation inhibitor for drilling fluid includes the following steps: Step 1: Dissolve the polymer containing secondary amine groups in an organic solvent to obtain a reaction solution; Step 2: Add an organotin catalyst to the reaction solution, stir and mix evenly, then add an isocyanate compound and continue stirring to obtain compound A.

[0014] The above-mentioned drilling fluid clay mineral surface hydration intercalation inhibitor is used to suppress clay mineral surface hydration.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The drilling fluid hydration intercalation inhibitor for clay mineral surfaces comprises a compound of formula A, wherein the compound of formula A comprises an IA portion, an IB portion, and an IC portion: The IA portion contains two -NH- groups, which have good hydrophilicity and are conducive to forming hydrogen bonds with water molecules in the silicate interlayer of clay minerals. Ar1 is selected from substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C5-C14 aryl, substituted or unsubstituted 3-10 heterocyclic or substituted or unsubstituted 5-10 heteroaryl. The planar structure of these cycloalkyl, aromatic, heterocyclic or heteroaryl groups, especially aromatic or heteroaryl groups, is conducive to being inserted into the interlayer structure of silicates in a monolayer form. In addition, the charge distribution of the aromatic group is changed due to its connection with the amide group, which is conducive to being inserted into the interlayer structure of silicates to achieve the purpose of "intercalation". The IB and IC moieties contain tertiary amine groups with a certain degree of hydrophilicity and R1 groups with hydrophobicity. Therefore, after the IA moieties complete intercalation, the IB and IC moieties can form hydrogen bonds with water molecules between silicate layers in the clay mineral due to the presence of the tertiary amine groups, while the hydrophobic R1 groups can prevent water molecules from penetrating and swelling on the surface of the clay mineral. Thus, the IA moieties can prevent the crystal layer expansion caused by hydration expansion of the clay mineral through intercalation, while the IB and IC moieties can prevent the permeation expansion caused by hydration expansion of the clay mineral through the intercalation of the IA moieties and their own hydrophilic-hydrophobic properties. Detailed Implementation

[0016] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0017] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0018] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0019] In this article, unless otherwise specified, the terms “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of”. For example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a”.

[0020] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0021] This invention provides a clay mineral surface hydration intercalation inhibitor for drilling fluids, the intercalation inhibitor comprising a compound of formula A having the following structure:

[0022] Where n1 and n2 are each independently selected from integers from 1 to 200; R1 is selected from substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C3-C16 cycloalkyl, substituted or unsubstituted C5-C14 aryl, substituted or unsubstituted 3-16 heterocyclic, or substituted or unsubstituted 5-14 heteroaryl. Ar1 is selected from substituted or unsubstituted C3-10 cycloalkyl groups, substituted or unsubstituted C5-C14 aryl groups, substituted or unsubstituted 3-10 heterocyclic groups, or substituted or unsubstituted 5-10 heteroaryl groups.

[0023] In one aspect of this disclosure, preferably, n1 and n2 are each independently selected from integers from 10 to 150.

[0024] In one aspect of the embodiments of this disclosure, preferably, R1 is selected from substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C2-C5 alkenyl, substituted or unsubstituted C2-C5 alkynyl, substituted or unsubstituted C1-C5 alkoxy, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C5-C12 aryl, substituted or unsubstituted 3-10 heterocyclic, or substituted or unsubstituted 5-10 heteroaryl.

[0025] In one aspect of the embodiments of this disclosure, preferably, R1 is selected from methyl, ethyl, or phenyl; the methyl, ethyl, or phenyl group is optionally substituted with one or more C1-C3 alkyl, amino, nitro, or hydroxyl groups.

[0026] In one aspect of the embodiments of this disclosure, more specifically, R1 is selected from ethyl.

[0027] In one aspect of the embodiments of this disclosure, compound A has the following structural formula:

[0028] In one aspect of the embodiments of this disclosure, specifically, Ar1 is selected from substituted or unsubstituted C5-C14 aryl groups; In one aspect of this disclosure, specifically, Ar1 is selected from... , or .

[0029] In one aspect of this disclosure, the values ​​of n1 and n2 are equal.

[0030] In one aspect of this disclosure, specifically, the intercalation inhibitor comprises at least one of a compound of formula A-1, a compound of formula A-2, or a compound of formula A-3 having the following structures:

[0031]

[0032] Where n1 and n2 are each independently selected from integers from 1 to 200.

[0033] In one aspect of this disclosure, the intercalation inhibitor further includes water; and, based on the total mass of the intercalation inhibitor, the mass percentage of compound A is 0.5% to 5%.

[0034] In one aspect of this disclosure, preferably, the mass percentage of compound A is 0.5% to 1.5% based on the total mass of the intercalation inhibitor. Specifically, the mass percentage of compound A is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5% based on the total mass of the intercalation inhibitor.

[0035] In one aspect of the embodiments of this disclosure, the intercalation inhibitor further includes one or more of emulsifiers, plugging agents, weighting agents, thickeners, lubricants, viscosity reducers, filtration reducers, or flocculants.

[0036] In one aspect of this disclosure, the emulsifier is selected from one or more of Spandex, Tween, OP, NP and AEO; and the HLB value of the emulsifier is selected from 1 to 10.

[0037] Span: Span series emulsifiers, also known as dehydrated sorbitan fatty acid esters, are a class of nonionic surfactants. They are produced by esterification of sorbitol and its anhydrides with various fatty acids. Depending on the fatty acid, there are several models such as Span-20, Span-40, Span-60, and Span-80. Different models of Span emulsifiers have different HLB values ​​and are widely used in water-in-oil emulsion systems.

[0038] Tween: Tween emulsifiers are polyoxyethylene sorbitan fatty acid esters, also belonging to the nonionic surfactant category. They are products of the reaction between Span emulsifiers and ethylene oxide. When used in conjunction with Span emulsifiers, they can form good emulsifying effects. Common models include Tween-20, Tween-40, Tween-60, and Tween-80, and are generally used in oil-in-water emulsion systems.

[0039] OP: OP series emulsifiers are alkylphenol polyoxyethylene ether nonionic surfactants, such as OP-10. They have good emulsifying, wetting and dispersing properties and are widely used in many fields such as chemical, textile and daily chemical industries.

[0040] NP: NP series emulsifiers are also alkylphenol polyoxyethylene ethers, similar to the OP series, but there may be some differences in structure and application performance. They also belong to nonionic surfactants and are often used for emulsification, solubilization and other functions.

[0041] AEO: AEO is the abbreviation for fatty alcohol polyoxyethylene ether, a type of nonionic surfactant. It is produced by the addition reaction of fatty alcohol and ethylene oxide. Depending on the carbon chain length of the fatty alcohol and the number of ethylene oxide addition reactions, there are various product types. It is used as an emulsifier and cleaning agent in industries such as detergents, textiles, and cosmetics.

[0042] The HLB value of an emulsifier, or Hydrophobic-Lipophile Balance, is an indicator used to measure the balance between hydrophilic and lipophilic groups in a surfactant molecule.

[0043] In one aspect of this disclosure, the mass percentage of the emulsifier, based on the total mass of the intercalation inhibitor, may be selected from 0.02% to 0.5%; specifically, based on the total mass of the intercalation inhibitor, the mass percentage of the emulsifier may be selected from 0.02%, 0.05%, 0.08%, 0.1%, 0.2%, 0.25%, 0.3%, 0.4%, or 0.5%.

[0044] In one aspect of this disclosure, the sealing agent may be selected from asphalt, sulfonated asphalt, nano-silica, or nano-barite; however, it is not limited thereto, and other commonly used options in the art may be used.

[0045] In one aspect of this disclosure, the mass percentage of the plugging agent may be selected from 0.01% to 0.2% based on the total mass of the intercalation inhibitor; specifically, the mass percentage of the plugging agent may be selected from 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, or 0.2% based on the total mass of the intercalation inhibitor.

[0046] In one aspect of this disclosure, the weighting agent may be selected from barite and / or iron ore powder; however, it is not limited thereto, and other commonly used options in the art may be used.

[0047] In one aspect of this disclosure, the weighting agent may be selected from 0.5% to 5% by mass, based on the total mass of the intercalation inhibitor; specifically, the plugging agent may be selected from 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, 3%, 3.5%, 4%, 4.5%, or 5% by mass, based on the total mass of the intercalation inhibitor.

[0048] In one aspect of this disclosure, the lubricant may be selected from nonionic surfactants; however, it is not limited thereto, and other commonly used options in the art may be used.

[0049] In one aspect of this disclosure, the mass percentage of the lubricant, based on the total mass of the intercalation inhibitor, can be selected from 0.25% to 3%; specifically, the mass percentage of the plugging agent, based on the total mass of the intercalation inhibitor, can be selected from 0.25%, 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, or 3%.

[0050] In one aspect of the embodiments of this disclosure, the filtration loss reducing agent may be selected from one or a mixture of several of the following: carboxymethyl cellulose (CMC) series, polyacrylic acid (PAC) series, sulfonated phenol-formaldehyde resin (SMP) series, hydrolyzed polyacrylonitrile salt (HPAN) series, and acrylate salt (SK) series; however, it is not limited thereto, and other commonly used options in the art may be used.

[0051] In one aspect of this disclosure, the mass percentage of the filtration reduction agent, based on the total mass of the intercalation inhibitor, may be selected from 0.3% to 5%; specifically, the mass percentage of the filtration reduction agent, based on the total mass of the intercalation inhibitor, may be selected from 0.3%, 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0052] In one aspect of the embodiments of this disclosure, the viscosity reducer may be selected from one or a mixture of several of sulfonyl tannin, sulfonyl tannin, sulfonated styrene-maleic anhydride copolymer and vinyl acetate-maleic anhydride copolymer; however, it is not limited thereto, and other options commonly used in the art may be used.

[0053] In one aspect of this disclosure, the mass percentage of the viscosity reducer, based on the total mass of the intercalation inhibitor, can be selected from 0.3% to 5%; specifically, based on the total mass of the intercalation inhibitor, the mass percentage of the viscosity reducer can be selected from 0.3%, 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0054] In one aspect of the embodiments of this disclosure, the flocculant may be selected from one or a combination of several of acrylonitrile copolymer potassium salt, acrylamide and sodium acrylate copolymer and complex ionic high molecular weight polymers; however, it is not limited thereto, and other options commonly used in the art may be used.

[0055] In one aspect of this disclosure, the mass percentage of the flocculant, based on the total mass of the intercalation inhibitor, can be selected from 0.2% to 3.5%; specifically, based on the total mass of the intercalation inhibitor, the mass percentage of the flocculant can be selected from 0.2%, 0.3%, 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, 3%, or 3.5%.

[0056] In one aspect of the embodiments of this disclosure, the thickener may be selected from one or a combination of several of high-viscosity polycationic cellulose, high-viscosity sodium carboxymethyl cellulose, acrylate-acrylamide copolymer and hydroxyethyl cellulose; however, it is not limited thereto, and other options commonly used in the art may be used.

[0057] In one aspect of this disclosure, the mass percentage of the thickener, based on the total mass of the intercalation inhibitor, may be selected from 0.3% to 5%; specifically, based on the total mass of the intercalation inhibitor, the mass percentage of the thickener may be selected from 0.3%, 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 2.75%, 3%, 3.5%, 4%, 4.5%, or 5%.

[0058] In one aspect of this disclosure, compound A can be prepared by the following steps: Step 1: Dissolve a polymer containing a secondary amine group in an organic solvent to obtain a solution with a solid content of 10% to 30%; preferably, obtain a solution with a solid content of 10% to 25%. Step 2: Add an organotin catalyst to the solution obtained in Step 1, stir and mix evenly, then add an isocyanate compound, and continue stirring for 45-90 minutes to obtain compound A.

[0059] In one aspect of the embodiments of this disclosure, the compound of formula A-1, formula A-2, or formula A-3 is prepared by the following steps: Step 1: Dissolve polyethyleneimine in an organic solvent to obtain a solution with a solid content of 10%~30%; Step 2: Add an organotin catalyst to the solution obtained in Step 1, stir and mix evenly, then add an isocyanate compound, and continue stirring for 45-90 minutes to obtain the compound of formula A-1, formula A-2 or formula A-3.

[0060] When the isocyanate compound is 1,5-naphthalene diisocyanate, compound A-1 is obtained; when the isocyanate compound is diphenylmethane diisocyanate, compound A-2 is obtained; when the isocyanate compound is dimethylbiphenyl diisocyanate, compound A-3 is obtained.

[0061] In one aspect of this disclosure, the mass ratio of the isocyanate compound to polyethyleneimine is selected from (1~15):100.

[0062] In one aspect of this disclosure, the average degree of polymerization of the polyethyleneimine is selected from 5 to 50; preferably, the average degree of polymerization of the polyethyleneimine is 7.

[0063] In one aspect of the embodiments of this disclosure, the organic solvent is selected from at least one of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dimethyl sulfoxide, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0064] In one aspect of the embodiments of this disclosure, the organotin catalyst is selected from any one of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, butyltin trichloride, monobutyltin oxide, dibutyltin oxide, and dibutyltin diacetate.

[0065] In one aspect of the embodiments of this disclosure, the mass of the added organotin catalyst is 0.1% to 0.5% of the mass of polyethyleneimine.

[0066] According to a second aspect of the present disclosure, the application of the aforementioned intercalation inhibitor is provided, wherein the intercalation inhibitor is used to inhibit hydration on the surface of clay minerals.

[0067] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0068] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0069] The list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another instance, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0070] In this disclosure, the term "alkyl" refers to an aliphatic hydrocarbon group, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, that link a linear alkyl chain. "Lower alkyl" refers to a group containing about 1 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0071] In this disclosure, the term "alkenyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon double bond, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkenyl chain. "Lower alkenyl" refers to a group containing about 2 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0072] In this disclosure, the term "alkynyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon triple bond, which can be straight-chain or branched. Branching refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkynyl chain. "Lower alkynyl" refers to a chain containing about 2 to about 6 carbon atoms, which can be straight-chain or branched. Non-limiting examples of alkynyl groups include ethynyl, propynyl, 2-butynyl, 3-methylbutynyl, n-pentynyl, and decynyl.

[0073] In this disclosure, the term "aryl" refers to an aromatic monocyclic or polycyclic ring system. An aryl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. Non-limiting examples of suitable aryl groups include phenyl and naphthyl.

[0074] In this disclosure, the term "heteroaryl" refers to an aromatic monocyclic or polycyclic ring system, wherein one or more ring atoms are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination, and preferably a heteroaryl contains about 5 to about 6 ring atoms. A "heteroaryl" may optionally be substituted by one or more "cyclic substituents," which may be the same or different, as defined herein. The prefixes azido, oxa, or thiado preceding the name of a heteroaryl root indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The nitrogen atom of a heteroaryl may optionally be oxidized to the corresponding N-oxide. Suitable, non-limiting examples of heteroaryl groups include pyridyl, pyrazinyl, furanyl, phenylthio, pyrimidinyl, isoxazolyl, isothiazolyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, pyrroleyl, pyrazolyl, triazolyl, 1,2,4-thiadiazolyl, pyrazinyl, pyridazinyl, quinoxalinyl, 2,3-diazanaphthyl, imidazo[1,2-a]pyridyl, imidazo[2,1-b]thiazolyl, benzofurazanyl, indoleyl, azaindoleyl, benzimidazolyl, benzothiopheneyl, quinolinyl, imidazolyl, thienopyridyl, quinazolinyl, thienopyrimidinyl, pyrrolopyridyl, imidazopyridyl, isoquinolinyl, benzoazaindoleyl, 1,2,4-triazinyl, benzothiazolyl, etc.

[0075] In this disclosure, the term "amino" refers to the -NR′R′′ group. The amino group may optionally be substituted. In an unsubstituted amino group, R′ and R′′ are hydrogen. In a substituted amino group, R′ and R′′ may each independently be, but not limited to, hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, alkylcycloalkyl, alkylheterocycloalkyl, alkoxy, sulfonyl, alkenyl, alkanoyl, aryl, arylalkyl, or heteroaryl, provided that R′ and R′′ are not both hydrogen. In a substituted amino group, R′ and R′′ may cyclize to form a cyclic amino group, such as pyrrolidinyl or piperidinyl. Such cyclic amino groups may incorporate other heteroatoms, for example, to form piperazine or morpholine groups. Such cyclic amino groups may optionally be substituted, for example, by an amino, hydroxyl, or oxo group.

[0076] In this disclosure, the term "alkoxy" refers to -O-alkyl. Alkoxy can refer to a straight-chain, branched, or cyclic, saturated or unsaturated oxy-hydrocarbon chain, including, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, and pentoxy. Alkoxy may optionally be substituted by one or more alkoxy substituents ("substituted alkoxy").

[0077] In this disclosure, the term "cycloalkyl" refers to a non-aromatic mono- or polycyclic ring system, preferably containing about 5 to about 7 ring atoms. The cycloalkyl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined above. Suitable monocyclic cycloalkyl groups, without limitation, include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. Suitable polycyclic cycloalkyl groups, without limitation, include 1-decahydronaphthyl, norcamphenyl, adamantyl, etc. In this disclosure, the term "cycloalkoxy" refers to a group in which one or more carbon atoms in the mono- or polycyclic ring system of the "cycloalkyl" group are substituted with oxygen atoms.

[0078] In this disclosure, the term "heterocyclic group" refers to a non-aromatic saturated monocyclic or polycyclic ring system, wherein one or more ring atoms in the ring system are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination. Adjacent oxygen and / or sulfur atoms are absent in the ring system, and preferred heterocycles contain about 5 to about 6 ring atoms. The prefixes aza, oxa, or thioa preceding the name of the heterocyclic group indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The heterocyclic group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. The nitrogen or sulfur atom of the heterocyclic group may optionally be oxidized to the corresponding N-oxide, S-oxide, or S,S-dioxide. Non-limiting examples of suitable monocyclic heterocyclic rings include piperidinyl, pyrrolyl, piperazine, morpholinyl, thiomorpholinyl, thiazolyl, 1,3-dioxolanecycloyl, 1,4-dioxacyclohexyl, tetrahydrofuranyl, tetrahydrophenylthio, tetrahydrothiopyranyl, etc.

[0079] In this disclosure, "hydration on the surface of clay minerals" includes surface hydration and osmotic hydration. Surface hydration refers to the formation of a hydration film of 1-4 layers of water molecules between the silicate layers of clay minerals. Osmotic hydration refers to the diffusion of exchange cations adsorbed on the surface of clay mineral layers into the aqueous phase to form a diffused electric double layer, which is formed between the clay minerals. The hydration process is produced by the combined action of the repulsive force of the electric double layer and the osmotic pressure.

[0080] Therefore, in this field, the hydration swelling of clay minerals is divided into two stages: crystal layer swelling and osmotic swelling. Crystal layer swelling is mainly caused by surface hydration of clay mineral crystal layers and hydration of interlayer cations. With increasing relative humidity, the water content between clay mineral layers increases from zero to approximately four water molecule layers. The interlayer spacing of clay minerals increases stepwise (discontinuously) with the increase in the number of interlayer water molecules, while the swelling pressure decreases with the increase in the number of water molecule layers. When the interlayer cations are fully hydrated and detach from the clay mineral surface to form a diffused double layer, crystal layer swelling ends and osmotic swelling begins. Due to the repulsion of the double layer, the clay mineral crystal layers are further pushed apart, causing the interlayer spacing to increase sharply until it is completely dispersed. Traditional descriptions of clay mineral crystal layer swelling use terms such as "single-layer hydration," "double-layer hydration," and "multi-layer hydration" to describe the gradual expansion or contraction of the interlayer spacing.

[0081] In this disclosure, "intercalation" refers to the reversible insertion of guest molecules into a layered host structure while maintaining the structural characteristics of the host. Intercalation of clay minerals containing various natural layered silicates has the following characteristics: (1) the interlayer contains water and organic matter; (2) it can change from a hydrophilic state to a hydrophobic state; (3) it exhibits a certain degree of acidity; and (4) it exists in the form of exchange with various inorganic or organic cations.

[0082] Therefore, in this field, for layered structures, organic derivatives as potential intercalating agents should be considered in the following ways: (1) the organic groups belong to two adjacent crystal layers, rather than interpenetrating each other. This would reduce steric hindrance to the diffusion of organic groups in the interlayer region; (2) the forces between adjacent crystal layers are expected to be van der Waals forces or hydrogen bonds.

[0083] This disclosure provides a compound of formula A having the following structure, wherein the compound of formula A comprises an IA moiety, an IB moiety, and an IC moiety:

[0084] The IA moiety contains two -NH- groups, which have good hydrophilicity and are conducive to forming hydrogen bonds with water molecules in the silicate interlayer of clay minerals. Ar1 is selected from aromatic groups with planar structures, which are conducive to insertion into the silicate interlayer structure in a monolayer form. In addition, the charge distribution of this aromatic group is changed due to its connection with the amide group, which is also conducive to insertion into the silicate interlayer structure, thus achieving the purpose of "intercalation". The IB and IC moiety contain tertiary amine groups with certain hydrophilicity and R1 groups with hydrophobicity. Therefore, after the IA moiety completes the intercalation, the IB and IC moiety can form hydrogen bonds with water molecules in the silicate interlayer of clay minerals due to the presence of tertiary amine groups, while the hydrophobic R1 groups can prevent water molecules from penetrating and expanding on the surface of clay minerals. Therefore, the IA moiety can prevent the crystal layer expansion caused by hydration expansion of clay minerals through intercalation, while the IB and IC moiety can prevent the penetration expansion caused by hydration expansion of clay minerals through the intercalation of the IA moiety and their own hydrophilic-hydrophobic properties.

[0085] In this disclosure, polyethyleneimine with a molecular weight of 300 is selected as the raw material; the degree of polymerization of polyethyleneimine with a molecular weight of 300 is approximately 7.

[0086] In this disclosure, when Ar1 is selected from naphthyl groups, its structure is most favorable for insertion into the interlayer structure of silicates in a monolayer planar manner.

[0087] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention were obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process was carried out at room temperature.

[0088] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention were obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process was carried out at room temperature.

[0089] Example 1 A method for preparing a drilling fluid clay mineral surface hydration intercalation inhibitor includes the following steps: 100 parts by weight of polyethyleneimine with a degree of polymerization of 300 were dissolved in 500 parts by weight of dimethylformamide, an organic solvent. Then, 0.15 parts by weight of dibutyltin dilaurate were added as a catalyst, and the mixture was stirred magnetically for 15 min. Then, 0.75 parts by weight of carboxymethyl cellulose, 0.06 parts by weight of Span 80, and 0.6 parts by weight of sulfomethyltannin were added, and the mixture was stirred for 30 min. Then, 75 parts by weight of 1,5-naphthalene diisocyanate were added, and the mixture was stirred for another 80 min. After the reaction was completed, the organic solvent was removed by rotary evaporation, and then the mixture was freeze-dried to obtain the intercalation inhibitor of Example 1. The structure of the intercalation inhibitor is shown below:

[0090] Example 2 A method for preparing a drilling fluid clay mineral surface hydration intercalation inhibitor includes the following steps: 100 parts by weight of polyethyleneimine with a degree of polymerization of 300 were dissolved in 500 parts by weight of dimethylformamide, an organic solvent. Then, 0.15 parts by weight of dibutyltin dilaurate were added as a catalyst, and the mixture was stirred magnetically for 15 min. Then, 0.75 parts by weight of carboxymethyl cellulose, 0.06 parts by weight of Span 80, and 0.6 parts by weight of sulfomethyltannin were added, and the mixture was stirred for 30 min. Then, 80 parts by weight of diphenylmethane diisocyanate were added, and the mixture was stirred for another 80 min. After the reaction was completed, the organic solvent was removed by rotary evaporation, and then the mixture was freeze-dried to obtain the intercalation inhibitor of Example 2. Its structure is shown below:

[0091] Example 3 A method for preparing a drilling fluid clay mineral surface hydration intercalation inhibitor includes the following steps: 100 parts by weight of polyethyleneimine with a degree of polymerization of 300 were dissolved in 500 parts by weight of dimethylformamide, an organic solvent. Then, 0.15 parts by weight of dibutyltin dilaurate were added as a catalyst, and the mixture was stirred magnetically for 15 min. Then, 0.75 parts by weight of carboxymethyl cellulose, 0.06 parts by weight of Span 80, and 0.6 parts by weight of sulfomethyltannin were added, and the mixture was stirred for 30 min. Then, 85 parts by weight of dimethylbiphenyl diisocyanate were added, and the mixture was stirred for another 80 min. After the reaction was completed, the organic solvent was removed by rotary evaporation, and then the intercalation inhibitor of Example 3 was obtained by freeze drying. Its structure is shown below:

[0092] Comparative Example 1 Comparative Example 1 includes the following steps: 100 parts by weight of polyethyleneimine with a degree of polymerization of 300, 0.75 parts by weight of carboxymethyl cellulose, 0.06 parts by weight of Span 80, 0.6 parts by weight of sulfomethyltannin, and 75 parts by weight of 1,5-naphthalene diisocyanate were added to 500 parts by weight of dimethylformamide, an organic solvent. The mixture was stirred for 80 min, the organic solvent was removed by rotary evaporation, and then the mixture was freeze-dried to obtain the intercalation inhibitor of Comparative Example 1.

[0093] Performance testing, including interlayer spacing testing and water absorption testing: Interlayer spacing test: Samples from Examples 1-3 and Comparative Example 1 were prepared into 2% inhibitor aqueous solutions. Sodium montmorillonite was dried at 150°C to constant weight, then divided into 4 portions, and added to the inhibitor aqueous solutions prepared in Examples 1-3 and Comparative Example 1, respectively. The mixtures were stirred for 24 hours, and then the suspensions were taken out, transferred to centrifuge tubes, and centrifuged at 4000 rpm for 10 minutes. The supernatant was discarded to obtain the precipitate. The lower precipitate sample was directly subjected to X-ray diffraction. X-ray diffraction analysis was performed to determine the interlayer spacing of sodium-based bentonite in different experimental slurries according to Bragg's equation. The remaining precipitate was vacuum dried at 80°C and then placed at room temperature under different humidity levels for 72 hours to test the unit water adsorption capacity. The results are shown in Table 1. Table 1 shows that the drilling fluid surface hydration intercalation inhibitor of the present invention exhibits a significant advantage in inhibiting surface hydration of clay minerals compared to Comparative Example 1 and untreated sodium montmorillonite. Specifically, the interlayer spacing of the treated clay samples in Examples 1-3 was significantly smaller than that of Comparative Example 1 and untreated sodium montmorillonite, indicating that the inhibitor in the examples more effectively limited the crystal expansion of clay minerals. Simultaneously, under relative humidity conditions of 40%, 60%, and 80%, the water absorption of Examples 1-3 was also significantly lower than that of Comparative Example 1 and untreated sodium montmorillonite, indicating that the inhibitor in the examples effectively reduced the permeation hydration of clay minerals. These data collectively demonstrate that the drilling fluid clay mineral surface hydration intercalation inhibitor provided by this invention can effectively inhibit the surface hydration of clay minerals, solving the technical problem that existing clay hydration inhibitors cannot completely inhibit the surface hydration of clay minerals.

[0094] Table 1

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A drilling fluid hydration intercalation inhibitor for clay mineral surfaces, characterized in that, Compound A containing the following structure: ； Where n1 and n2 are each independently selected from integers from 1 to 200; R1 is selected from substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, substituted or unsubstituted C1-C10 alkoxy, substituted or unsubstituted C3-C16 cycloalkyl, substituted or unsubstituted C5-C14 aryl, substituted or unsubstituted 3-16 heterocyclic, or substituted or unsubstituted 5-14 heteroaryl. Ar1 is selected from substituted or unsubstituted C3-10 cycloalkyl groups, substituted or unsubstituted C5-C14 aryl groups, substituted or unsubstituted 3-10 heterocyclic groups, or substituted or unsubstituted 5-10 heteroaryl groups.

2. The drilling fluid clay mineral surface hydration intercalation inhibitor according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C2-C5 alkenyl, substituted or unsubstituted C2-C5 alkynyl, substituted or unsubstituted C1-C5 alkoxy, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C5-C12 aryl, substituted or unsubstituted 3-10 heterocyclic or substituted or unsubstituted 5-10 heteroaryl.

3. The drilling fluid clay mineral surface hydration intercalation inhibitor according to claim 1, characterized in that, R1 is selected from methyl, ethyl, or phenyl; the methyl, ethyl, or phenyl group may optionally be substituted with one or more C1-C3 alkyl, amino, nitro, or hydroxyl groups.

4. The drilling fluid hydration intercalation inhibitor for clay mineral surfaces according to claim 1, characterized in that, Ar1 is selected from substituted or unsubstituted C5-C14 aryl groups.

5. The drilling fluid clay mineral surface hydration intercalation inhibitor according to claim 1, characterized in that, Ar1 is selected from , or .

6. The drilling fluid clay mineral surface hydration intercalation inhibitor according to claim 1, characterized in that, n1 and n2 are each independently selected from integers between 10 and 150.

7. The drilling fluid hydration intercalation inhibitor for clay mineral surfaces according to claim 1, characterized in that, The intercalation inhibitor comprises at least one of the following compounds: Formula A-1, Formula A-2, or Formula A-3: 、 、 。 8. The drilling fluid hydration intercalation inhibitor for clay mineral surfaces according to claim 1, characterized in that, Based on the total mass of the intercalation inhibitor, the mass percentage of compound A is 0.5% to 5%.

9. The method for preparing the drilling fluid clay mineral surface hydration intercalation inhibitor according to any one of claims 1 to 8, characterized in that, Includes the following steps: Step 1: Dissolve the polymer containing secondary amine groups in an organic solvent to obtain a reaction solution; Step 2: Add an organotin catalyst to the reaction solution, stir and mix evenly, then add an isocyanate compound and continue stirring to obtain compound A.

10. The application of the drilling fluid clay mineral surface hydration intercalation inhibitor according to any one of claims 1 to 8 in inhibiting clay mineral surface hydration.

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