A foaming agent system and its preparation method and application

Abstract

The present invention relates to the field of chemical additives for oilfield drilling, and discloses a gemini quaternary ammonium salt surfactant, a foaming agent system, a preparation method and application thereof. The preparation method comprises: (1) in the presence of a first catalyst, an alkylphenol and a polyformaldehyde are subjected to a first reaction to obtain a first intermediate product; (2) in the presence of a second catalyst, the first intermediate product and epichlorohydrin are subjected to a second reaction to obtain a second intermediate product; (3) the second intermediate product and triethanolamine are subjected to a third reaction to obtain a gemini quaternary ammonium salt surfactant. The gemini quaternary ammonium salt surfactant has both strong foaming performance and inhibition performance. When used as a component of a foaming agent system for underbalanced foam drilling, the rock carrying capacity of the foaming agent system can be improved, and the effects of inhibiting collapse prevention, suspending rock carrying and rapid drilling can be achieved. The provided foaming agent system has fewer components, avoids the compatibility problem of multiple components, and has a simple on-site use process.

Description

Technical Field

[0001] The invention relates to a chemical auxiliary agent for oilfield drilling, and in particular to a gemini quaternary ammonium salt surfactant, a foaming agent system, and a preparation method and application thereof. Background Art

[0002] When gas drilling encounters formation water, corresponding treatment methods are often used according to the amount of water produced. However, in field applications, water plugging or water absorption operations often cannot achieve satisfactory results. Therefore, gas drilling is usually converted to foam drilling. Foam drilling uses gas drilling fluid, which has unique advantages in protecting oil and gas layers and preventing formation leakage. It is an effective supplement to solve the problem of formation water and significantly increase the mechanical drilling speed.

[0003] Compared with pure gas drilling, the foam fluid used in foam drilling has high viscosity and shear force, strong suspension and rock carrying capacity, and can effectively solve the technical problem that gas drilling cannot be smoothly constructed when water is produced in the formation. It is one of the more ideal drilling technologies for oil and gas reservoir exploration and development such as fracture reservoirs with large leakage, pressure depletion formations, and low-pressure and low-permeability formations. However, since the liquid column pressure formed by the foam fluid during foam drilling cannot balance the collapse pressure of the formation, and the air foam fluid cannot form mud cakes on the well wall, it is very easy to cause well wall instability when drilling in water-sensitive shale formations such as water expansion and water collapse, causing complex accidents such as stuck pipe, leading to the failure of the drilling project. Therefore, it is particularly critical to use a strong inhibitory foam drilling fluid system for underbalanced drilling.

[0004] CN100535075C discloses a highly inhibitory circulatory micro-foam drilling fluid or completion fluid, comprising: a base slurry and an additive, wherein the base slurry is formulated as follows: 2-3 parts by weight of bentonite, 2-3 parts by weight of salt-resistant clay, 0.2-0.3 parts by weight of soda ash and 100 parts by weight of water; the additive is formulated as follows: 1-5 parts by weight of a composite inhibitor SD-YZ, 0.5-3 parts by weight of a low-density viscosity enhancer SD-LVC, 1-3 parts by weight of a low-density viscosity enhancer and fluid loss reducer SD-LAC, 1-5 parts by weight of a low-density flow pattern regulator SD-LRC and 1.5-2.5 parts by weight of a low-density regulator composition SD-LDC. Among them, the composite inhibitor SD-YZ, low-density viscosity enhancer SD-LVC, low-density viscosity enhancer and filtration loss reducer SD-LAC, low-density flow pattern regulator SD-LRC, and low-density regulator SD-LDC are all compounded from a variety of chemical agents. The highly inhibitory recyclable micro-foam drilling fluid or completion fluid system is very complex, and puts forward strict process control requirements for field applications.

[0005] In summary, providing a foaming agent system with strong foaming performance, inhibition performance, simple composition, and easy on-site application is of great significance for solving the wellbore instability problem in underbalanced drilling. Summary of the invention

[0006] The purpose of the present invention is to provide a gemini quaternary ammonium salt surfactant, a foaming agent system, a preparation method and an application thereof, in view of the problems that the existing foaming agent system for underbalanced drilling has insufficient foaming performance and inhibition performance, complex composition and unsatisfactory compatibility between components.

[0007] In order to achieve the above-mentioned object, the present invention provides a gemini quaternary ammonium salt surfactant in the first aspect, wherein the surfactant has a structural formula shown in formula (1);

[0008]

[0009] Wherein, R is a C6-C12 alkyl group.

[0010] The second aspect of the present invention provides a method for preparing the gemini quaternary ammonium salt surfactant described in the first aspect, comprising:

[0011] (1) in the presence of a first catalyst, subjecting an alkylphenol to a first reaction with paraformaldehyde to obtain a first intermediate product;

[0012] (2) in the presence of a second catalyst, subjecting the first intermediate product to a second reaction with epichlorohydrin to obtain a second intermediate product;

[0013] (3) subjecting the second intermediate product to a third reaction with triethanolamine to obtain a gemini quaternary ammonium salt surfactant;

[0014] The alkylphenol has the structural formula shown in formula (2); the first intermediate product has the structural formula shown in formula (3); the second intermediate product has the structural formula shown in formula (4); in formula (2), formula (3) and formula (4), R is a C6-C12 alkyl group.

[0015]

[0016] The third aspect of the present invention provides a foaming agent system, which comprises, based on the total weight of the foaming agent system: 5-35wt% of a surfactant, 0.5-3wt% of a high molecular polymer and 62-94.5wt% of water;

[0017] Wherein, the surfactant is the gemini quaternary ammonium salt surfactant described in the first aspect above.

[0018] The fourth aspect of the present invention provides a method for preparing the foaming agent system according to the third aspect, comprising: fully mixing water with a high molecular polymer, and further fully mixing the obtained mixture with a surfactant to obtain a foaming agent system;

[0019] The amounts of the high molecular polymer, surfactant and water are such that, based on the total weight of the foaming agent system, the content of the surfactant in the foaming agent system is 5-35wt%, the content of the high molecular polymer is 0.5-3wt% and the content of water is 62-94.5wt%.

[0020] The fifth aspect of the present invention provides use of the foaming agent system described in the third aspect or the foaming agent system prepared by the method described in the fourth aspect in underbalanced foam drilling.

[0021] Through the above technical solution, the beneficial effects of the present invention are:

[0022] (1) A specific molecular structure design is adopted to integrate the foaming performance and the inhibition performance into the molecular structure of the same Gemini quaternary ammonium salt surfactant, so that it has both strong foaming performance and inhibition performance;

[0023] (2) The foaming agent system contains the above-mentioned specific gemini quaternary ammonium salt surfactant and a biodegradable green environmentally friendly polymer, which can effectively improve the rock carrying capacity of the foaming agent system, thereby achieving the effects of inhibiting collapse, suspending rock carrying and rapid drilling;

[0024] (3) The foaming agent system has fewer components, avoiding the compatibility problems existing in multiple components, and the on-site use process is simple. DETAILED DESCRIPTION

[0025] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0027] In a first aspect, the present invention provides a gemini quaternary ammonium salt surfactant having a structural formula shown in formula (1);

[0028]

[0029] Wherein, R is a C6-C12 alkyl group.

[0030] According to the present invention, as shown in formula (1), described gemini type quaternary ammonium salt surfactant has symmetrical structure, wherein, R can be straight chain or contain branched alkyl, does not contain any substituent in described straight chain or contain branched alkyl, and the total number of carbon atoms is 6-12.When R is to contain branched alkyl, should comprise the situation of various isomers that satisfy the total carbon atoms contained by this alkyl.Described gemini type quaternary ammonium salt surfactant can be the single substance (namely R is only selected from a kind of in its various isomers) that satisfies structural formula shown in formula (1), also can be the mixture of various isomers that satisfies structural formula shown in formula (1).

[0031] According to the present invention, the Gemini quaternary ammonium salt surfactant adopts a specific molecular structure design, and contains a benzene ring rigid structure, a quaternary ammonium salt structure and an ether bond in its molecule, and has the effect of integrating strong foaming performance and inhibition performance.

[0032] According to the present invention, based on the structural formula shown in formula (1), preferably, when R is a C8-C12 alkyl group, the gemini quaternary ammonium salt surfactant can have better foaming performance and inhibition performance; more preferably, when R is a C8-C12 straight-chain alkyl group, further advantages in foaming performance and inhibition performance can be obtained.

[0033] The second aspect of the present invention provides a method for preparing the gemini quaternary ammonium salt surfactant described in the first aspect, comprising:

[0034] (1) in the presence of a first catalyst, subjecting an alkylphenol to a first reaction with paraformaldehyde to obtain a first intermediate product;

[0035] (2) in the presence of a second catalyst, subjecting the first intermediate product to a second reaction with epichlorohydrin to obtain a second intermediate product;

[0036] (3) subjecting the second intermediate product to a third reaction with triethanolamine to obtain a gemini quaternary ammonium salt surfactant;

[0037] The alkylphenol has the structural formula shown in formula (2); the first intermediate product has the structural formula shown in formula (3); the second intermediate product has the structural formula shown in formula (4); in formula (2), formula (3) and formula (4), R is a C6-C12 alkyl group.

[0038]

[0039] According to the present invention, in step (1), the alkyl group R in the alkylphenol is located in the para position of the hydroxyl group, and R can be a straight chain or branched alkyl group, in which the straight chain or branched alkyl group does not contain any substituent, and the total number of carbon atoms is 6-12. When R is a branched alkyl group, the situation of various isomers that meet the total number of carbon atoms contained in the alkyl group should be included. The alkylphenol can be a single substance that meets the structural formula shown in formula (2) (i.e., R is only selected from one of its various isomers), or it can be a mixture of various isomers that meet the structural formula shown in formula (2).

[0040] According to the present invention, preferably, R is a C8-C12 alkyl group, more preferably a C8-C12 straight-chain alkyl group.

[0041] According to the present invention, in step (1), the molecular formula of the paraformaldehyde is (HCHO) n , wherein the present invention does not limit the value of n.

[0042] According to the present invention, in step (1), the process of the first reaction is as follows:

[0043]

[0044] Specifically, the alkylphenol and the first catalyst may be sequentially added to a reaction container, heated together, and after the temperature reaches the required reaction temperature, paraformaldehyde is added to carry out the first reaction. After the reaction is completed, the reaction is filtered to obtain the first intermediate product.

[0045] According to the present invention, in step (1), preferably, the first catalyst can be a solid acid catalyst, which can be obtained commercially, for example, the solid superacid catalyst model HND-31, HND-32 or HND-33 produced by Jiangyin Nanda Synthetic Chemical Co., Ltd.

[0046] According to the present invention, in step (1), preferably, the weight ratio of the alkylphenol: paraformaldehyde: first catalyst can be 2: (0.8-1): (0.02-0.1).

[0047] According to the present invention, in step (1), preferably, the conditions of the first reaction include: the temperature can be 80-120° C., and the time can be 4-7 hours. The first intermediate product obtained after the first reaction is methyl-coupled bisalkylphenol.

[0048] According to the present invention, in step (2), the process of the second reaction is as follows:

[0049]

[0050] Specifically, the first intermediate product and the second catalyst may be first added into a reaction container, heated together, and after the temperature is raised to the required reaction temperature, epichlorohydrin is added to carry out the second reaction to obtain the second intermediate product.

[0051] According to the present invention, in step (2), preferably, the second catalyst may be boron trifluoride etherate complex.

[0052] According to the present invention, in step (2), preferably, the weight ratio of the first intermediate product: epichlorohydrin: second catalyst can be 1: (15-28): (0.01-0.04).

[0053] According to the present invention, in step (2), preferably, the conditions of the second reaction include: the temperature can be 65-90° C., and the time can be 3-7 hours.

[0054] According to the present invention, in step (3), the process of the third reaction is as follows:

[0055]

[0056] Specifically, the second intermediate product can be first added to a reaction container and heated, preferably heated to 40-70°C, and then triethanolamine is added, preferably the addition time is controlled to be 0.5-2h. After the addition is completed, the temperature is raised to the required reaction temperature to carry out the third reaction. After the reaction is completed, the product is recrystallized with acetone to obtain a gemini quaternary ammonium salt surfactant.

[0057] According to the present invention, in step (3), preferably, the weight ratio of the second intermediate product to triethanolamine can be 0.5:(0.9-1.2).

[0058] According to the present invention, in step (3), preferably, the conditions of the third reaction include: the temperature can be 50-90° C., and the time can be 3-6 hours.

[0059] The third aspect of the present invention provides a foaming agent system, which comprises, based on the total weight of the foaming agent system: 5-35wt% of a surfactant, 0.5-3wt% of a high molecular polymer and 62-94.5wt% of water;

[0060] Wherein, the surfactant is the gemini quaternary ammonium salt surfactant described in the first aspect above.

[0061] According to the present invention, in the foaming agent system, the high molecular polymer is a biodegradable green high molecular polymer, which can be selected from at least one of sesbania gum, guar gum, sesame gum, fenugreek gum and konjac gum, and has the functions of increasing the viscosity of the foam system, enhancing the foam strength and stability, and improving the rock-carrying capacity of the foaming system.

[0062] In the present invention, preferably, the high molecular weight polymer can be selected from at least one of carboxymethyl guar gum, hydroxyethyl guar gum, hydroxypropyl guar gum and cationic guar gum; more preferably, it can be selected from hydroxyethyl guar gum and / or hydroxypropyl guar gum.

[0063] According to the present invention, the foaming agent system contains the Gemini quaternary ammonium salt surfactant described in the first aspect of the present invention, which can have both strong foaming performance and inhibition performance, and at the same time synergize with the biodegradable green and environmentally friendly polymer, thereby effectively improving the suspension and rock carrying capacity of the foaming agent system, inhibiting the hydration and collapse of mudstone, and achieving rapid drilling. The foaming agent system has fewer components, so it can avoid the compatibility problems caused by mutual influence or difficulty in coexistence of multiple components, and is convenient for on-site preparation and application.

[0064] The fourth aspect of the present invention provides a method for preparing the foaming agent system according to the third aspect, comprising: fully mixing water with a high molecular polymer, and further fully mixing the obtained mixture with a surfactant to obtain a foaming agent system;

[0065] The amounts of the high molecular polymer, surfactant and water are such that, based on the total weight of the foaming agent system, the content of the surfactant in the foaming agent system is 5-35wt%, the content of the high molecular polymer is 0.5-3wt% and the content of water is 62-94.5wt%.

[0066] According to the present invention, in the preparation method of the foaming agent system, it is preferred to first disperse and dissolve the high molecular polymer in water, and make the obtained mixture solution free of "fish-eye" insoluble matter produced by aggregation of the high molecular polymer, and then add a surfactant, and after sufficient mixing, obtain a uniform solution system, i.e., the foaming agent system.

[0067] The fifth aspect of the present invention provides use of the foaming agent system described in the third aspect or the foaming agent system prepared by the method described in the fourth aspect in underbalanced foam drilling.

[0068] The present invention will be described in detail below through preparation examples and examples. In the following preparation examples and examples, unless otherwise specified, all are conventional methods; the reagents and materials described, unless otherwise specified, can be obtained from commercial sources.

[0069] In the following preparation examples,

[0070] Hexylphenol, heptylphenol, octylphenol, and dodecylphenol were purchased from Sinopharm Reagent Company;

[0071] Solid catalysts HND-31, HND-32 and HND-33 were purchased from Jiangyin Nanda Synthetic Chemical Co., Ltd.

[0072] Preparation Example 1

[0073] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0074] (1) Add dodecylphenol and HND-31 catalyst to a dry four-necked flask, heat to the reaction temperature, slowly add paraformaldehyde, and carry out a first reaction at 90° C. for 4 h. After the reaction is completed, separate and purify to obtain a first intermediate product;

[0075] Wherein, the weight ratio of dodecylphenol: paraformaldehyde: HND-31 catalyst is 2:1:0.04;

[0076] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 70° C. for 3 h. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0077] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:15:0.02;

[0078] (3) The second intermediate product was added to a dry four-necked flask and heated to 40°C. Then, triethanolamine was slowly added for 2 hours. After the addition was completed (the weight ratio of the second intermediate product to triethanolamine was 0.5:1), the temperature was raised to 80°C for a third reaction for 5 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P1.

[0079] Preparation Example 2

[0080] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0081] (1) octylphenol and HND-31 catalyst are added to a dry four-necked flask, the temperature is raised to the reaction temperature, paraformaldehyde is slowly added, and a first reaction is carried out at 80° C. for 6 hours. After the reaction is completed, a first intermediate product is obtained by separation and purification;

[0082] Wherein, the weight ratio of octylphenol: paraformaldehyde: HND-31 catalyst is 2:0.9:0.05;

[0083] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 90° C. for 3 h. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0084] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:20:0.02;

[0085] (3) Add the second intermediate product to a dry four-necked flask and heat to 50°C. Then slowly add triethanolamine for 1 hour. After the addition is completed (the weight ratio of the second intermediate product to triethanolamine is 0.5:0.9), heat to 80°C for a third reaction for 5 hours. After the reaction is completed, the product is recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which is recorded as P2.

[0086] Preparation Example 3

[0087] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0088] (1) adding hexylphenol and HND-33 catalyst into a dry four-necked flask, heating to the reaction temperature, slowly adding paraformaldehyde, and performing a first reaction at 100° C. for 5 h. After the reaction is completed, separating and purifying to obtain a first intermediate product;

[0089] Wherein, the weight ratio of hexylphenol: paraformaldehyde: HND-33 catalyst is 2:0.8:0.08;

[0090] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 90° C. for 5 h. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0091] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:15:0.03;

[0092] (3) The second intermediate product was added to a dry four-necked flask and heated to 70°C. Then, triethanolamine was slowly added for 2 hours. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1.1), the temperature was raised to 90°C for a third reaction for 3 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium surfactant, which was recorded as P3.

[0093] Preparation Example 4

[0094] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0095] (1) octylphenol and HND-32 catalyst are added to a dry four-necked flask, the temperature is raised to the reaction temperature, paraformaldehyde is slowly added, and a first reaction is carried out at 120° C. for 4 hours. After the reaction is completed, a first intermediate product is obtained by separation and purification;

[0096] Wherein, the weight ratio of octylphenol: paraformaldehyde: HND-32 catalyst is 2:1:0.02;

[0097] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 80° C. for 5 h. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0098] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:28:0.04;

[0099] (3) The second intermediate product was added to a dry four-necked flask and heated to 60°C. Then, triethanolamine was slowly added for 1.5 hours. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:0.9), the temperature was raised to 80°C for a third reaction for 6 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P4.

[0100] Preparation Example 5

[0101] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0102] (1) Add dodecylphenol and HND-33 catalyst to a dry four-necked flask, heat to the reaction temperature, slowly add paraformaldehyde, and carry out a first reaction at 90° C. for 5 h. After the reaction is completed, separate and purify to obtain a first intermediate product;

[0103] Wherein, the weight ratio of dodecylphenol: paraformaldehyde: HND-33 catalyst is 2:0.9:0.05;

[0104] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 80° C. for 4 hours. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0105] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:18:0.04;

[0106] (3) The second intermediate product was added to a dry four-necked flask and heated to 40°C. Then triethanolamine was slowly added for 2 hours. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1), the temperature was raised to 50°C for a third reaction for 6 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P5.

[0107] Preparation Example 6

[0108] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0109] (1) adding heptylphenol and HND-32 catalyst into a dry four-necked flask, heating to the reaction temperature, slowly adding paraformaldehyde, and conducting a first reaction at 120° C. for 4 h. After the reaction is completed, separating and purifying to obtain a first intermediate product;

[0110] Wherein, the weight ratio of heptylphenol: paraformaldehyde: HND-32 catalyst is 2:0.8:0.04;

[0111] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 90° C. for 4 hours. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0112] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:20:0.03;

[0113] (3) The second intermediate product was added to a dry four-necked flask and heated to 50°C. Then, triethanolamine was slowly added for 0.5 h. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1.2), the temperature was raised to 90°C for a third reaction for 4 h. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P6.

[0114] Preparation Example 7

[0115] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0116] (1) Add dodecylphenol and HND-3 catalyst to a dry four-necked flask, heat to the reaction temperature, slowly add paraformaldehyde, and carry out the first reaction at 80° C. for 7 h. After the reaction is completed, separate and purify to obtain the first intermediate product;

[0117] Wherein, the weight ratio of dodecylphenol: paraformaldehyde: HND-3 catalyst is 2:1:0.1;

[0118] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 65° C. for 6 hours. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0119] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:22:0.03;

[0120] (3) The second intermediate product was added to a dry four-necked flask and heated to 60°C. Then, triethanolamine was slowly added for 1 hour. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1.2), the temperature was raised to 80°C for a third reaction for 5 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P7.

[0121] Preparation Example 8

[0122] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0123] (1) adding hexylphenol and HND-32 catalyst into a dry four-necked flask, heating to the reaction temperature, slowly adding paraformaldehyde, and performing a first reaction at 100° C. for 6 h. After the reaction is completed, separating and purifying to obtain a first intermediate product;

[0124] Wherein, the weight ratio of hexylphenol: paraformaldehyde: HND-32 catalyst is 2:1:0.05;

[0125] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 65° C. for 6 hours. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0126] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:15:0.04;

[0127] (3) The second intermediate product was added to a dry four-necked flask and heated to 70°C. Then, triethanolamine was slowly added for 2 hours. After the addition was completed (the weight ratio of the second intermediate product to triethanolamine was 0.5:0.9), the temperature was raised to 90°C for a third reaction for 4 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P8.

[0128] Preparation Example 9

[0129] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0130] (1) adding heptylphenol and HND-33 catalyst into a dry four-necked flask, heating to the reaction temperature, slowly adding paraformaldehyde, and conducting a first reaction at 120° C. for 5 h. After the reaction is completed, separating and purifying to obtain a first intermediate product;

[0131] Wherein, the weight ratio of heptylphenol: paraformaldehyde: HND-33 catalyst is 2:0.9:0.1;

[0132] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 90° C. for 4 hours. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0133] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:28:0.02;

[0134] (3) The second intermediate product was added to a dry four-necked flask and heated to 60°C. Then, triethanolamine was slowly added for 0.5 h. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1), the temperature was raised to 90°C for a third reaction for 5 h. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P9.

[0135] Preparation Example 10

[0136] This preparation example illustrates the preparation of Gemini quaternary ammonium salt surfactants

[0137] (1) Add dodecylphenol and HND-33 catalyst to a dry four-necked flask, heat to the reaction temperature, slowly add paraformaldehyde, and carry out a first reaction at 90° C. for 7 h. After the reaction is completed, separate and purify to obtain a first intermediate product;

[0138] Wherein, the weight ratio of dodecylphenol: paraformaldehyde: HND-33 catalyst is 2:0.9:0.02;

[0139] (2) Add the first intermediate product and boron trifluoride ether complex into a dry four-necked flask with condensation, heat to the reaction temperature, slowly add epichlorohydrin, and carry out a second reaction at 65° C. for 5 h. After the reaction is completed, purify the product system to obtain a second intermediate product;

[0140] Wherein, the weight ratio of the first intermediate product: epichlorohydrin: boron trifluoride ether complex is 1:26:0.03;

[0141] (3) The second intermediate product was added to a dry four-necked flask and heated to 60°C. Then, triethanolamine was slowly added for 1.5 hours. After the addition was completed (the weight ratio of the second intermediate product: triethanolamine was 0.5:1), the temperature was raised to 90°C for a third reaction for 5 hours. After the reaction was completed, the product was recrystallized from acetone to obtain a gemini quaternary ammonium salt surfactant, which was recorded as P10.

[0142] Example 1

[0143] The preparation of the foaming agent system is described in this example.

[0144] At room temperature, first slowly add 0.5 g of hydroxyethyl guar gum into a beaker containing 94.5 g of water while stirring. Stir for 1 hour until the polymer is completely dissolved. Then slowly add 5 g of the gemini quaternary ammonium salt surfactant P1 obtained in Preparation Example 1. Continue stirring for 1 hour to obtain a foaming agent system, recorded as S1.

[0145] Example 2

[0146] The preparation of the foaming agent system is described in this example.

[0147] At room temperature, first slowly add 0.5g of carboxymethyl guar gum into a beaker containing 89.5g of water while stirring. Stir for 1 hour until the polymer is completely dissolved. Then slowly add 10g of the gemini quaternary ammonium salt surfactant P2 obtained in Preparation Example 2. Continue stirring for 1 hour to obtain a foaming agent system, recorded as S2.

[0148] Example 3

[0149] The preparation of the foaming agent system is described in this example.

[0150] At room temperature, first slowly add 0.5 g of hydroxyethyl guar gum into a beaker containing 64.5 g of water while stirring. Stir for 1 hour until the polymer is completely dissolved. Then slowly add 35 g of the gemini quaternary ammonium salt surfactant P3 obtained in Preparation Example 3. Continue stirring for 1 hour to obtain a foaming agent system, recorded as S3.

[0151] Example 4

[0152] The preparation of the foaming agent system is described in this example.

[0153] At room temperature, first slowly add 2 g of carboxymethyl guar gum into a beaker containing 68 g of water while stirring. Stir for 1 hour until the polymer is completely dissolved. Then slowly add 30 g of the gemini quaternary ammonium salt surfactant P4 obtained in Preparation Example 4. Continue stirring for 1 hour to obtain a foaming agent system, recorded as S4.

[0154] Example 5

[0155] The preparation of the foaming agent system is described in this example.

[0156] At room temperature, first slowly add 3 g of hydroxypropyl guar gum into a beaker containing 92 g of water while stirring. Stir for 1 h until the polymer is completely dissolved. Then slowly add 5 g of the gemini quaternary ammonium salt surfactant P5 obtained in Preparation Example 5. Continue stirring for 1 h to obtain a foaming agent system, recorded as S5.

[0157] Example 6

[0158] The preparation of the foaming agent system is described in this example.

[0159] At room temperature, first slowly add 3 g of hydroxyethyl guar gum into a beaker containing 62 g of water while stirring. Stir for 1 hour until the polymer is completely dissolved. Then slowly add 35 g of the gemini quaternary ammonium salt surfactant P6 obtained in Preparation Example 6 and continue stirring for 1 hour to obtain a foaming agent system, recorded as S6.

[0160] Example 7

[0161] The preparation of the foaming agent system is described in this example.

[0162] At room temperature, first slowly add 1 g of cationic guar gum into a beaker containing 79 g of water while stirring. Stir for 1 h until the polymer is completely dissolved. Then slowly add 20 g of the gemini quaternary ammonium salt surfactant P7 obtained in Preparation Example 7. Continue stirring for 1 h to obtain a foaming agent system, recorded as S7.

[0163] Example 8

[0164] The preparation of the foaming agent system is described in this example.

[0165] At room temperature, first slowly add 2 g of hydroxypropyl guar gum into a beaker containing 78 g of water while stirring. Stir for 1 h until the polymer is completely dissolved. Then slowly add 20 g of the gemini quaternary ammonium salt surfactant P8 obtained in Preparation Example 8. Continue stirring for 1 h to obtain a foaming agent system, recorded as S8.

[0166] Example 9

[0167] The preparation of the foaming agent system is described in this example.

[0168] At room temperature, first slowly add 4 g of hydroxypropyl guar gum into a beaker containing 86 g of water while stirring. Stir for 1 h until the polymer is completely dissolved. Then slowly add 10 g of the gemini quaternary ammonium salt surfactant P9 obtained in Preparation Example 9. Continue stirring for 1 h to obtain a foaming agent system, recorded as S9.

[0169] Example 10

[0170] The preparation of the foaming agent system is described in this example.

[0171] At room temperature, 3 g of carboxymethyl guar gum was slowly added to a beaker containing 72 g of water while stirring for 1 h until the polymer was completely dissolved. Then 25 g of the gemini quaternary ammonium salt surfactant P10 prepared in Preparation Example 10 was slowly added and stirring was continued for 1 h to obtain a foaming agent system, which was recorded as S10.

[0172] Comparative Example 1

[0173] The method of Example 1 was followed, except that the gemini quaternary ammonium salt surfactant P1 obtained in Preparation Example 1 was replaced by hexadecyltrimethylammonium chloride (purchased from Sinopharm Reagent Company), and other conditions were the same as in Example 1 to obtain a foaming agent system, which was recorded as D1.

[0174] Test Case

[0175] The foaming performance test and the inhibition performance test were respectively carried out on the foaming agent systems S1-S10 and D1 prepared in Examples 1-10 and Comparative Example 1, and the existing foaming agent used in oil fields (hexadecyltrimethylammonium chloride, purchased from Sinopharm Reagent Company).

[0176] 1. Foaming performance evaluation

[0177] Take 2.0g of the foaming agent product (i.e., S1-S10, D1, and the existing foaming agent hexadecyltrimethylammonium chloride used in oil field field), add it to 198.0g of deionized water to prepare a foaming agent solution; take 100mL of the foaming agent solution and pour it into a stirring cup, stir it at 11000 rpm for 1min; start timing after stirring stops, pour the generated foam into a measuring cylinder, measure the foam volume (mL), and record the time taken for 50mL of liquid to precipitate (liquid precipitation half-life, min) and the time taken for the foam to disappear to half of the initial volume (foam half-life, min). The results are shown in Table 1.

[0178] 2. Evaluation of inhibition performance

[0179] According to the standard "SY-T5613-2000 Test Method for Physical and Chemical Properties of Shale", the core rolling recovery rate of shale in clean water and foaming agent aqueous solution (the foaming agents are S1-S10, D1 and the existing foaming agent hexadecyltrimethylammonium chloride used in oil field) was tested.

[0180] Specific steps: weigh 20.0g of the initial core of 4-8 mesh, place it in a high-temperature aging kettle, then add 350mL of clean water or an equal volume of a 1.0wt% foaming agent aqueous solution into the above aging kettle, heat roll at 120℃ for 16h and take it out, pass the taken out core through a 100-mesh sieve, dry the sieve residue (rock cuttings) at 105℃ for 4h, and weigh the recovered rock cuttings after cooling to room temperature. The ratio of the weight (g) of the recovered rock cuttings to the weight (g) of the initial core is the core rolling recovery rate. The results are shown in Table 1.

[0181] Table 1

[0182]

[0183] Note: Blank sample refers to clean water without any foaming agent or inhibitor.

[0184] As can be seen from Table 1, the foam volume generated by the foaming agent system S1-S10 provided by the present invention in the foaming performance test is significantly greater than that of the existing foaming agent hexadecyl trimethyl ammonium chloride used in the oil field, and the liquid separation half-life and foam half-life are also longer than the latter, which indicates that S1-S10 has stronger foaming performance. Comparing the core rolling recovery rates corresponding to different foaming agents in the above evaluation method, the foaming agent system S1-S10 provided by the present invention has a stronger effect of inhibiting the hydration and dispersion of the core, which is manifested in that the core rolling recovery rate is significantly higher than that of the existing foaming agent hexadecyl trimethyl ammonium chloride used in the oil field. At a dosage of 1.0wt%, the core rolling recovery rate of hot rolling at 120°C for 16h is greater than 75%, and can be as high as 90%.

[0185] In particular, the Gemini quaternary ammonium salt surfactant provided by the present invention is not used in the formulation of the foaming agent D1 component, and the foaming performance and inhibition performance are significantly different from those of S1-S10.

[0186] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A foaming agent system, characterized in that: Based on the total weight of the foaming agent system, the foaming agent system comprises: 5-35wt% of a surfactant, 0.5-3wt% of a high molecular polymer and 62-94.5wt% of water; Wherein, the surfactant is a gemini quaternary ammonium salt surfactant having the structural formula shown in formula (1), Wherein, R is a C6-C12 alkyl group.

2. The foaming agent system according to claim 1, wherein R is a C8-C12 alkyl group.

3. The foaming agent system according to claim 1 or 2, wherein R is a C8-C12 straight chain alkyl group.

4. The foaming agent system according to claim 1, wherein The preparation method of the gemini quaternary ammonium salt surfactant comprises: (1) in the presence of a first catalyst, subjecting an alkylphenol to a first reaction with paraformaldehyde to obtain a first intermediate product; (2) in the presence of a second catalyst, subjecting the first intermediate product to a second reaction with epichlorohydrin to obtain a second intermediate product; (3) subjecting the second intermediate product to a third reaction with triethanolamine to obtain a gemini quaternary ammonium salt surfactant; The alkylphenol has a structural formula shown in formula (2); the first intermediate product has a structural formula shown in formula (3); the second intermediate product has a structural formula shown in formula (4); in formula (2), formula (3) and formula (4), R is a C6-C12 alkyl group; 5. The foaming agent system according to claim 4, wherein R is a C8-C12 alkyl group.

6. The blowing agent system according to claim 5, wherein R is a C8-C12 straight chain alkyl group.

7. The blowing agent system according to claim 4, wherein The first catalyst is a solid acid catalyst; the second catalyst is a boron trifluoride ether complex.

8. The blowing agent system according to claim 4, wherein In step (1), the weight ratio of the alkylphenol: paraformaldehyde: first catalyst is 2: (0.8-1): (0.02-0.1); And / or, the conditions of the first reaction include: temperature of 80-120° C. and time of 4-7 h.

9. The blowing agent system according to claim 4, wherein In step (2), the weight ratio of the first intermediate product: epichlorohydrin: second catalyst is 1: (15-28): (0.01-0.04); And / or, the conditions of the second reaction include: temperature of 65-90° C. and time of 3-7 h.

10. The blowing agent system according to claim 4, wherein In step (3), the weight ratio of the second intermediate product to triethanolamine is 0.5:(0.9-1.2); And / or, the conditions of the third reaction include: temperature of 50-90° C. and time of 3-6 h.

11. The blowing agent system according to claim 1, wherein The high molecular polymer is selected from at least one of sesbania gum, guar gum, flax gum, fenugreek gum and konjac gum.

12. The blowing agent system according to claim 11, wherein The high molecular polymer is selected from at least one of carboxymethyl guar gum, hydroxyethyl guar gum, hydroxypropyl guar gum and cationic guar gum.

13. The blowing agent system according to claim 12, wherein The high molecular polymer is selected from hydroxyethyl guar gum and / or hydroxypropyl guar gum.

14. A method for preparing the blowing agent system according to any one of claims 1 to 13, characterized in that: include: Fully mixing water and high molecular polymer, and further fully mixing the obtained mixture with a surfactant to obtain a foaming agent system; The amounts of the high molecular polymer, surfactant and water are such that, based on the total weight of the foaming agent system, the content of the surfactant in the foaming agent system is 5-35wt%, the content of the high molecular polymer is 0.5-3wt% and the content of water is 62-94.5wt%.

15. Use of the foaming agent system according to any one of claims 1 to 13 in underbalanced foam drilling.

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