Thermal association tackifier as well as preparation method and application thereof

Abstract

The invention discloses a thermal association tackifier which comprises the following raw materials in parts by weight: 10-50 parts of an alkenyl amide monomer, 20-50 parts of an alkenyl thermosensitive rigid monomer, 20-50 parts of an alkenyl sulfonic acid monomer and 5-20 parts of an alkenyl cationic monomer. The thermal association tackifier contains a plurality of functional groups such as a rigid thermosensitive group, a temperature-resistant and salt-resistant group and the like, so that the rigidity of a main chain of the tackifier can be enhanced, the thermal stability of a molecular chain of the tackifier is improved, a relatively strong association structure can be formed at high temperature and high salt, and the rheological property of the drilling fluid can be regulated and controlled through the association of the thermosensitive group in a molecule; further, the rheological property of the drilling fluid under high-temperature and high-salt conditions is improved, and the drilling fluid has excellent tackifying and temperature-resistant properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oilfield chemicals, in particular to a thermal association tackifier and a preparation method and application thereof. BACKGROUND

[0002] Tackifier is a key agent in drilling fluid treatment agent, and has been one of the research focuses in the field of drilling fluid. With the development of oil exploration and development to deep layer, higher requirements for temperature resistance and salt resistance of tackifier are put forward. However, the temperature resistance and salt resistance of traditional tackifiers such as acryl polymer and xanthan gum are poor, which can not meet the more stringent application conditions of deep high-temperature drilling fluid, so the development of efficient temperature-resistant tackifier for deep high-temperature oil and gas reservoir drilling fluid is highly valued by drilling fluid workers.

[0003] At present, the tackifiers commonly used in the drilling fluid field at home and abroad are mainly high molecular substances such as xanthan gum and polyacryl, but the above tackifiers are prone to molecular chain degradation or curling under high temperature and high salt, resulting in serious loss of tackifier viscosity. At present, the main research methods to improve the temperature resistance and salt resistance of tackifier are to introduce temperature-resistant and salt-resistant monomers into the polymer molecules, to prepare modified acrylamide polymers (such as hydrophobic association polymer), to cross-link the polymer, etc., but these methods have many shortcomings: due to the low reactivity of temperature-resistant and salt-resistant monomers, the molecular weight of the polymer is low and the tackifying effect is poor; the hydrophobic association polymer has the disadvantage of poor solubility, and the molecular chain mainly composed of acrylamide cannot avoid the high temperature hydrolysis of amide group; the cross-linking degree and distribution, structure morphology and gelation time of the cross-linked polymer are difficult to control accurately.

[0004] Yan Zhaopeng et al. prepared 2-acrylamidododecane sulfonic acid (AMC12S) by using 1-dodecene, acrylonitrile and fuming sulfuric acid as raw materials, and then synthesized water-soluble terpolymer AM / AA / AMC12S by using acrylamide (AM), acrylic acid (AA) and AMC12S as raw materials. The terpolymer AM / AA / AMC12S was characterized by infrared spectroscopy and scanning electron microscopy. Compared with partially hydrolyzed polyacrylamide (HPAM), the copolymer has good temperature resistance and salt resistance. However, the highest temperature of this technology is only 90℃, the viscosity retention rate is less than 50%, and higher temperature is not explored.

[0005] Fu Yue synthesized temperature-responsive amphoteric ion polymer (PADN) by using aqueous solution polymerization method and copolymerizing 2-acrylamido-2-methylpropane sulfonic acid (AMPS), dimethyl diallyl ammonium chloride (DMDAAC) and N-vinyl pyrrolidone (NVP). The temperature resistance and salt resistance of the polymer were evaluated. The research results show that the polymer has good temperature resistance within 150℃, but its high temperature resistance is poor, which cannot be applied to high temperature oil and gas field, limiting its application and development.

[0006] Hu Wen-ting et al. studied the method of synthesizing polyacrylate sodium (PAAS) with acrylamide (AM), acrylic acid (AA) and sodium hydroxide (NaOH) as raw materials. The results of tackifying performance evaluation experiment show that when the mass percentage of acrylic acid, acrylamide and initiator in total monomers is 54%, 25% and 1% respectively, and the polymerization reaction temperature is 70℃, the tackifying rate of the synthesized polyacrylic acid sodium to the base pulp can reach 243.1% when the addition amount is 1%, and the base pulp has good tackifying effect. However, the temperature resistance and salt resistance of the tackifier are not tested, and it cannot be judged whether the polymer still has the effect under high temperature and high salt.

[0007] Xiao Jibin takes nonionic monomer acrylamide, anionic monomer 2-acrylamido-2-methylpropanesulfonic acid and cationic monomer methacryloyloxyethyl trimethyl ammonium chloride as synthetic monomers, and performs aqueous solution polymerization under an ammonium persulfate and sodium bisulfite redox initiation system to synthesize a terpolymer. The formate drilling fluid prepared by using the tackifier has high dynamic shear force and plastic viscosity, and strong salt resistance and calcium contamination resistance. However, the viscosity of the copolymer tackifier decreases greatly at a temperature of 120℃, and the temperature resistance is insufficient.

[0008] Zhang Dongling takes acrylamide, AMPS and PPB as monomers, and K2S2O8+NaHSO3 oxidation / reduction system as an initiator to perform polymerization through aqueous solution free radical micellar polymerization to synthesize the required hydrophobic association type high-temperature resistant polymer TV-1. The application results show that the solid-free drilling fluid with TV-1 as a tackifier has good rock carrying, high-temperature resistance and salt resistance at a temperature of 150℃. However, the polymer tackifier has insufficient high-temperature resistance above 150℃, and the synthesis cost is relatively high.

[0009] Chinese patent document CN104140790A discloses a water-soluble polymer tackifier for oil fields and a preparation method thereof, and mainly solves the problem of insufficient calcium resistance of the water-soluble polymer. The water-soluble polymer tackifier can still maintain good tackifying effect in a water solution with a calcium chloride concentration of 15% at 120℃. The tackifier can be used for drilling fluid tackifiers, and can also be used in the field of polymer oil displacement agents and other oil field chemical related fields. However, the tackifier polymer belongs to modified polymers of xanthan gum or hydroxyethyl cellulose, and cannot fundamentally solve the temperature resistance and salt resistance of the tackifier. The temperature resistance can only reach 120℃. SUMMARY

[0010] In view of this, in order to overcome the defects such as insufficient temperature resistance of the tackifier for water-based drilling fluid in the prior art, the present application provides a thermal association tackifier and a preparation method and application thereof. The thermal association tackifier has good tackifying performance and viscosity retention rate under a high-temperature environment of 165℃ and a high-salt environment of 20%.

[0011] To achieve the above object, the present application adopts the following technical solutions:

[0012] A kind of hot association tackifier, including the following weight parts of raw materials: alkenyl amide monomer 10~50 parts, alkenyl thermosensitive rigid monomer 20~50 parts, alkenyl sulfonic acid monomer 20~50 parts, alkenyl cation monomer 5~20 parts.

[0013] In an alternative embodiment, the viscosity average molecular weight of the hot association tackifier is 800000~1500000.

[0014] In an alternative embodiment, the alkenyl amide monomer is selected from at least one of acrylamide, N,N-dimethyl acrylamide, N-vinyl formamide, N-vinyl acetamide and N-hexadecyl acrylamide, etc.

[0015] In an alternative embodiment, the alkenyl thermosensitive rigid monomer is selected from at least one of N-isopropyl acrylamide, N-vinyl caprolactam, 2-acrylamido hexadecane sulfonic acid and 2-acrylamido octadecane sulfonic acid, etc.

[0016] In an alternative embodiment, the alkenyl sulfonic acid monomer is selected from at least one of propylene sulfonic acid, methacryl sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid, etc.

[0017] In an alternative embodiment, the alkenyl cation monomer is selected from at least one of dimethyl diallyl ammonium chloride, methallyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, etc.

[0018] The present application also provides a preparation method of the above-mentioned hot association tackifier, comprising the following steps:

[0019] S1: dissolving alkenyl amide monomer, alkenyl thermosensitive rigid monomer, alkenyl sulfonic acid monomer and alkenyl cation monomer in water to obtain a mixed monomer solution;

[0020] S2: adjusting the pH value of the mixed monomer solution to neutral with an alkaline solution, then controlling the system in an oxygen-free atmosphere, adding an initiator to initiate polymerization reaction, and after the polymerization reaction is completed, purifying, drying and crushing to obtain a hot association tackifier.

[0021] In an alternative embodiment, the alkaline solution can be selected from any one of sodium hydroxide solution, potassium hydroxide solution and ammonia water; preferably sodium hydroxide solution.

[0022] In an alternative embodiment, the total concentration of monomers in the mixed monomer solution is 15%~25%.

[0023] The above control system is not particularly limited in an oxygen-free atmosphere, and can be achieved by replacing air in the system with an inert gas such as nitrogen in a conventional manner in the art.

[0024] In an alternative embodiment, the temperature of the polymerization reaction is 50-80 DEG C, and the time is 6-8 hours.

[0025] In an alternative embodiment, the initiator is selected from at least one of ammonium persulfate, potassium persulfate, azobisdimethylvaleric acid hydrochloride, benzoyl peroxide, azobisdimethylvaleric acid hydrochloride, azobisdimethylimidazoline hydrochloride, azobisdimethylvaleric acid, and the like.

[0026] In an alternative embodiment, the amount of the initiator is 0.2-0.5% of the total mass of the monomers.

[0027] The above heat associating tackifier or the heat associating tackifier prepared by the above method can be used in a water-based drilling fluid.

[0028] Compared with the prior art, the present application has at least the following beneficial effects:

[0029] Beneficial effect 1: The heat associating tackifier provided by the present application contains a plurality of functional groups such as rigid heat-sensitive groups and temperature-resistant and salt-resistant groups in the molecule by using specific polymerization monomers and limiting the amount thereof, which can enhance the rigidity of the tackifier main chain, improve the thermal stability of the tackifier molecular chain, and form a strong association structure under high temperature and high salt conditions, because the addition of inorganic salt enhances the polarity of the solution, thereby promoting the hydrophobic association between the molecular side chains, so that the polymer molecular chain forms a coarse and tight association network structure, and the rheological properties of the drilling fluid are regulated through the association of the heat-sensitive groups in the molecule, thereby improving the rheological properties of the drilling fluid under high temperature and high salt conditions, and the heat associating tackifier has excellent tackifying and temperature-resistant properties. Moreover, the viscosity-average molecular weight of the heat associating tackifier is limited to 800000-1500000, and compared with acryl-based polymer tackifiers, the heat associating tackifier provided by the present application has a lower molecular weight, a faster dissolution speed, and the like.

[0030] Beneficial effect 2: The preparation method of the heat associating tackifier provided by the present application is simple, stable, and the like. DETAILED DESCRIPTION

[0031] The application will be described in detail below by examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the protection scope of the application, and those skilled in the art can make some non-essential improvements and adjustments to the application according to the above content of the application.

[0032] If the specific experimental steps or conditions are not specified in the examples, the operation or conditions can be carried out according to the conventional experimental steps described in the literature in the art. If the reagents or instruments used are not specified by the manufacturer, they are all conventional reagent products that can be obtained by purchase.

[0033] The commercially available raw materials can meet the implementation of the technical solutions of the application, and the raw materials involved in the following examples and comparative examples are as follows:

[0034] Raw materials:

[0035] Acrylamide, N,N-dimethyl acrylamide, N-isopropyl acrylamide, N-vinyl formamide, N-vinyl acetamide, N-vinyl caprolactam; all with a purity of 98%, all purchased from Macklin.

[0036] 2-acrylamido-2-methylpropanesulfonic acid, methacryloyloxyethyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride, methacryloyl sulfonic acid; all of analytical purity, all purchased from Aldrin.

[0037] Ammonium persulfate, potassium persulfate, azobisdimethylvaleric acid, azobisdimethylvaleric acid, azobisdimethylvaleric acid, benzoyl peroxide, all of analytical purity, all purchased from Chinese Reagent Network.

[0038] N-hexadecyl acrylamide, analytical purity, purchased from Delta Biological;

[0039] 2-acrylamidohexadecane sulfonic acid, 2-acrylamido octadecane sulfonic acid, analytical purity, purchased from Rui Shi Reagent;

[0040] Methyl allyl trimethyl ammonium chloride, analytical purity, purchased from Leyan Reagent;

[0041] Propylene sulfonic acid, analytical purity, purchased from Huayuan Mall.

[0042] Equipment sources:

[0043] ZNN-D6 rotary viscometer, Jiamo Instrument;

[0044] OFITE high temperature and high pressure rheometer, roller furnace, OFITE Company, USA.

[0045] The total concentration of monomers in the mixed monomer solution can be 15% to 25%, but for the purpose of comparison, the total concentration of monomers in the mixed monomer solution in the following examples and comparative examples is 20%.

[0046] The viscosity average molecular weight of the thermally associating viscosity enhancer prepared in the following examples is between 800000 and 1500000.

[0047] Example 1

[0048] The present example provides a thermally associating viscosity enhancer, and the preparation method thereof comprises the following steps:

[0049] Take 25g of acrylamide, 25g of N-vinyl formamide, 10g of N-isopropyl acrylamide, 10g of N-vinyl caprolactam, 20g of propylene sulfonic acid, 10g of 2-acrylamido-2-methylpropane sulfonic acid, and 10g of dimethyldiallylammonium chloride as the olefinic amide monomers, the olefinic thermosensitive rigid monomers, the olefinic sulfonic acid monomers, and the olefinic cationic monomers, respectively. Dissolve them in water to form a mixed monomer solution, so that the total concentration of monomers is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7. Replace the air, especially oxygen, in the system by passing nitrogen into the system for 30 minutes at room temperature. Take 0.26g of ammonium persulfate and 0.1g of potassium persulfate as initiators, dissolve them in water to form a solution, and slowly add them to the mixed monomer solution. At the same time, set the temperature to 55°C to carry out the polymerization reaction for 7 hours. Then, a white viscous product is obtained. Wash the polymer with acetone to remove the unreacted monomers, and then put it into an oven at a temperature of 70°C for drying. After the polymer is completely dried, use a pulverizer to crush it (no particle size is required). Thus, a thermally associating viscosity enhancer is obtained.

[0050] Example 2

[0051] The present example provides a thermally associating viscosity enhancer, and the preparation method thereof comprises the following steps:

[0052] Take 15 g of alkenyl amide monomer N,N-dimethyl acrylamide, 15 g of acrylamide, 10 g of alkenyl thermosensitive rigid monomer N-isopropyl acrylamide, 10 g of 2-acrylamido octadecane sulfonic acid, 20 g of alkenyl sulfonic acid monomer propylene sulfonic acid, 10 g of methacryl sulfonic acid, 10 g of alkenyl cationic monomer methacryloyloxyethyl trimethyl ammonium chloride, dissolve in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and blow nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.27 g of initiator azobisimidozoline hydrochloride, dissolve in water to form a solution, and slowly drop into the mixed monomer solution, while setting the temperature to 65°C for polymerization for 7 h, then wash the polymer with acetone to remove unreacted monomers, and then put it into an oven at a temperature of 70°C for drying treatment, and after the polymer is completely dried, use a pulverizer to crush it, and the thermally associated tackifier is obtained.

[0053] Example 3

[0054] The present embodiment provides a thermally associated tackifier, and the preparation method thereof comprises the following steps:

[0055] Take 5 g of alkenyl amide monomer N-vinyl formamide, 5 g of N-vinyl acetamide, 15 g of alkenyl thermosensitive rigid monomer 2-acrylamido octadecane sulfonic acid, 5 g of 2-acrylamido hexadecane sulfonic acid, 25 g of alkenyl sulfonic acid monomer methacryl sulfonic acid, 5 g of 2-acrylamido-2-methylpropane sulfonic acid, and 10 g of alkenyl cationic monomer methallyl trimethyl ammonium chloride, dissolve in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and blow nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.2 g of initiator azobisimidozoline hydrochloride and 0.15 g of azobis cyanovaleric acid, dissolve in water to form a solution, and slowly drop into the mixed monomer solution, while setting the temperature to 75°C for polymerization for 6 h, to obtain a white viscous product, then wash the polymer with acetone to remove unreacted monomers, and then put it into an oven at a temperature of 70°C for drying treatment, and after the polymer is completely dried, use a pulverizer to crush it, and the thermally associated tackifier is obtained.

[0056] Example 4

[0057] The present embodiment provides a thermally associated tackifier, and the preparation method thereof comprises the following steps:

[0058] Take 15 g of N-vinyl formamide, 15 g of N-hexadecyl acrylamide, 30 g of 2-acrylamido hexadecane sulfonic acid, 30 g of 2-acrylamido-2-methylpropane sulfonic acid, and 10 g of methacryloyloxyethyl trimethyl ammonium chloride, respectively, as the monomers, and dissolve them in water to form a mixed monomer solution with a total monomer concentration of 20%. Adjust the pH of the solution to 7-8 using 20% sodium hydroxide, and replace the air, especially oxygen, in the system by bubbling nitrogen through the system for 30 minutes at room temperature. Take 0.2 g of benzoyl peroxide and 0.15 g of azobis cyano valeric acid, dissolve them in water to form a solution, and slowly add the solution to the mixed monomer solution. Perform the polymerization reaction at a temperature of 80°C for 6 hours to obtain a white viscous product. Wash the polymer with acetone to remove the unreacted monomers, and then dry the polymer in an oven at a temperature of 70°C. After the polymer is completely dried, crush it with a crusher to obtain the thermal association tackifier.

[0059] Example 5

[0060] The present example provides a thermal association tackifier, and a method for preparing the same includes the following steps:

[0061] Take 10 g of N-vinyl formamide, 10 g of N-hexadecyl acrylamide, and 10 g of N,N-dimethyl acrylamide, respectively, as the monomers, and dissolve them in water to form a mixed monomer solution with a total monomer concentration of 20%. Take 40 g of 2-acrylamido octadecane sulfonic acid, 30 g of acrylic sulfonic acid, and 10 g of methacryloyloxyethyl trimethyl ammonium chloride, respectively, as the monomers, and dissolve them in water to form a mixed monomer solution with a total monomer concentration of 20%. Adjust the pH of the solution to 7-8 using 20% sodium hydroxide, and replace the air, especially oxygen, in the system by bubbling nitrogen through the system for 30 minutes at room temperature. Take 0.2 g of azobis diisobutyl amide hydrochloride and 0.2 g of azobis cyano valeric acid, dissolve them in water to form a solution, and slowly add the solution to the mixed monomer solution. Perform the polymerization reaction at a temperature of 55°C for 6 hours to obtain a white viscous product. Wash the polymer with acetone to remove the unreacted monomers, and then dry the polymer in an oven at a temperature of 70°C. After the polymer is completely dried, crush it with a crusher to obtain the thermal association tackifier.

[0062] Example 6

[0063] The present example provides a thermal association tackifier, and a method for preparing the same includes the following steps:

[0064] Take 15 g of vinylamide monomer N-vinyl formamide, 15 g of acrylamide, 30 g of alkenyl thermosensitive rigid monomer 2-acrylamido hexadecane sulfonic acid, 20 g of N-vinyl caprolactam, 30 g of alkenyl sulfonic acid monomer methacryl sulfonic acid, 10 g of alkenyl cationic monomer dimethyl diallyl ammonium chloride, and 5 g of methacryloyloxyethyl trimethyl ammonium chloride, dissolve them in water to form a mixed monomer solution with a total monomer concentration of 20%, adjust the pH of the solution to 7-8 using 20% sodium hydroxide, and replace the air, especially oxygen, in the system by passing nitrogen through the system for 30 min at room temperature. Take 0.2 g of azobisdimethylamino propane hydrochloride and 0.25 g of azobis cyano valeric acid, dissolve them in water to form a solution, and slowly add the solution to the mixed monomer solution. Perform a polymerization reaction at a temperature of 60°C for 7 h to obtain a white viscous product. Wash the polymer with acetone to remove unreacted monomers, and then place the polymer in an oven at a temperature of 70°C for drying treatment. After the polymer is completely dried, crush it using a crusher to obtain a thermal association tackifier.

[0065] Example 7

[0066] This example provides a thermal association tackifier, and a preparation method thereof includes the following steps:

[0067] Take 15 g of vinylamide monomer N-vinyl formamide, 10 g of N-hexadecyl acrylamide, and 5 g of N,N-dimethyl acrylamide, 30 g of alkenyl thermosensitive rigid monomer N-isopropyl acrylamide, 10 g of alkenyl sulfonic acid monomer 2-acrylamido-2-methylpropane sulfonic acid, 10 g of propylene sulfonic acid, and 20 g of alkenyl cationic monomer methallyl trimethyl ammonium chloride, dissolve them in water to form a mixed monomer solution with a total monomer concentration of 20%, adjust the pH of the solution to 7-8 using 20% sodium hydroxide, and replace the air, especially oxygen, in the system by passing nitrogen through the system for 30 min at room temperature. Take 0.25 g of azobis cyano valeric acid, dissolve it in water to form a solution, and slowly add the solution to the mixed monomer solution. Perform a polymerization reaction at a temperature of 65°C for 7 h to obtain a white viscous product. Wash the polymer with acetone to remove unreacted monomers, and then place the polymer in an oven at a temperature of 70°C for drying treatment. After the polymer is completely dried, crush it using a crusher to obtain a thermal association tackifier.

[0068] Example 8

[0069] This example provides a thermal association tackifier, and a preparation method thereof includes the following steps:

[0070] Take 30 g of acrylamide, 15 g of 2-acrylamidohexadecane sulfonic acid, 15 g of 2-acrylamido octadecane sulfonic acid, 40 g of methacryl sulfonic acid, 5 g of methallyl trimethyl ammonium chloride, dissolve in water to form a mixed monomer solution, the total monomer concentration is 20%, adjust the pH of the solution to 7-8 with 20% sodium hydroxide, and replace the air in the system with nitrogen for 30 min at room temperature. Take 0.3 g of azobis cyano valeric acid as an initiator, dissolve in water to form a solution, and slowly add it to the mixed monomer solution. The temperature is set to 55°C for polymerization for 5 h, and a white viscous product is obtained. Wash the polymer with acetone to remove unreacted monomers, then put it in an oven at 70°C for drying treatment. After the polymer is completely dried, use a pulverizer to crush it, and the thermal association tackifier is obtained.

[0071] Example 9

[0072] This example provides a thermal association tackifier, and the preparation method comprises the following steps:

[0073] Take 15 g of N-vinyl formamide, 15 g of N,N-dimethyl acrylamide, 15 g of 2-acrylamidohexadecane sulfonic acid, 15 g of N-vinyl caprolactam, 20 g of propylene sulfonic acid, 30 g of methacryl sulfonic acid, and 20 g of methallyl trimethyl ammonium chloride, dissolve in water to form a mixed monomer solution, the total monomer concentration is 20%, adjust the pH of the solution to 7-8 with 20% sodium hydroxide, and replace the air in the system with nitrogen for 30 min at room temperature. Take 0.2 g of azobis isobutyl amidine hydrochloride and 0.25 g of azobis cyano valeric acid as initiators, dissolve in water to form a solution, and slowly add it to the mixed monomer solution. The temperature is set to 55°C for polymerization for 6 h, and a white viscous product is obtained. Wash the polymer with acetone to remove unreacted monomers, then put it in an oven at 70°C for drying treatment. After the polymer is completely dried, use a pulverizer to crush it, and the thermal association tackifier is obtained.

[0074] Example 10

[0075] This example provides a thermal association tackifier, and the preparation method comprises the following steps:

[0076] Take 15 g of alkenyl amide monomer N-vinyl acetamide, 10 g of alkenyl thermosensitive rigid monomer 2-acrylamido hexadecane sulfonic acid, 20 g of 2-acrylamido octadecane sulfonic acid, 30 g of alkenyl sulfonic acid monomer methacryl sulfonic acid, and 15 g of alkenyl cationic monomer dimethyl diallyl ammonium chloride, respectively, dissolve them in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and then introduce nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.3 g of initiator azobisdimethylaminoformamide hydrochloride, dissolve it in water to form a solution, and slowly add it to the mixed monomer solution, and set the temperature to 65°C for polymerization for 8 h to obtain a white viscous product. Wash the polymer with acetone to remove unreacted monomers, then put it into an oven at 70°C for drying treatment. After the polymer is completely dried, use a pulverizer to crush it, and the thermally associated tackifier is obtained.

[0077] Comparative Example 1

[0078] The present comparative example provides a thermally associated tackifier, and the preparation method thereof comprises the following steps:

[0079] Take 15 g of alkenyl amide monomer N,N-dimethyl acrylamide, 15 g of acrylamide, 10 g of alkenyl thermosensitive rigid monomer N-isopropyl acrylamide, and 10 g of 2-acrylamido octadecane sulfonic acid, respectively, 20 g of alkenyl sulfonic acid monomer acryl sulfonic acid, and 10 g of methacryl sulfonic acid, dissolve them in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and then introduce nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.27 g of initiator azobisdimethylimidazole hydrochloride, dissolve it in water to form a solution, and slowly add it to the mixed monomer solution, and set the temperature to 65°C for polymerization for 7 h. Wash the polymer with acetone to remove unreacted monomers, then put it into an oven at 70°C for drying treatment. After the polymer is completely dried, use a pulverizer to crush it, and the thermally associated tackifier comparative sample is obtained.

[0080] Comparative Example 2

[0081] The present comparative example provides a thermally associated tackifier, and the preparation method thereof comprises the following steps:

[0082] Take 15 g of alkenyl amide monomer N-vinyl formamide, 15 g of alkenyl amide monomer N-hexadecyl acrylamide, 30 g of alkenyl thermosensitive rigid monomer 2-acrylamido hexadecyl sulfonic acid, and 10 g of alkenyl cationic monomer methacryloyloxyethyl trimethyl ammonium chloride, respectively, dissolve them in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and then introduce nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.2 g of initiator benzoyl peroxide and 0.15 g of azobis cyanovaleric acid, dissolve them in water to form a solution, and slowly add the solution to the mixed monomer solution, and set the temperature to 80°C for polymerization for 6 h to obtain a white viscous product, wash the polymer with acetone to remove unreacted monomers, and then place it in an oven at 70°C for drying treatment. After the polymer is completely dried, it is crushed using a crusher to obtain a hot associating tackifier comparative sample.

[0083] Comparative Example 3

[0084] The present comparative example provides a hot associating tackifier, and the preparation method thereof comprises the following steps:

[0085] Take 15 g of alkenyl amide monomer N-vinyl formamide, 15 g of alkenyl amide monomer N-hexadecyl acrylamide, 30 g of alkenyl thermosensitive rigid monomer 2-acrylamido hexadecyl sulfonic acid, and 10 g of alkenyl cationic monomer methacryloyloxyethyl trimethyl ammonium chloride, respectively, dissolve them in water to form a mixed monomer solution, so that the total monomer concentration is 20%, and use 20% sodium hydroxide to adjust the pH of the solution to 7-8, and then introduce nitrogen into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. Take 0.2 g of initiator benzoyl peroxide and 0.15 g of azobis cyanovaleric acid, dissolve them in water to form a solution, and slowly add the solution to the mixed monomer solution, and set the temperature to 80°C for polymerization for 6 h to obtain a white viscous product, wash the polymer with acetone to remove unreacted monomers, and then place it in an oven at 70°C for drying treatment. After the polymer is completely dried, it is crushed using a crusher to obtain a hot associating tackifier comparative sample.

[0086] Comparative Example 4

[0087] The present comparative example provides a hot associating tackifier, and the preparation method thereof comprises the following steps:

[0088] The monomers of the alkenyl amide type, N-vinyl formamide 15 g, the monomers of the alkenyl thermosensitive rigid type, 2-acrylamidohexadecane sulfonic acid 15 g, the monomers of the alkenyl sulfonic acid type, methacryl sulfonic acid 30 g, the monomers of the alkenyl cationic type, dimethyldiallyl ammonium chloride 30 g, were dissolved in water to form a mixed monomer solution, and the total concentration of the monomers was 20%. The pH of the solution was adjusted to 7-8 using sodium hydroxide with a concentration of 20%. Nitrogen was bubbled into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. The initiator, azobisdimethylamino propane hydrochloride 0.3 g, was dissolved in water to form a solution, which was slowly added to the mixed monomer solution. The temperature was set to 65°C, and the polymerization reaction was carried out for 8 h. A white viscous product was obtained. The polymer was washed with acetone to remove the unreacted monomers, and then placed in an oven at a temperature of 70°C for drying treatment. After the polymer was completely dried, it was crushed using a crusher to obtain the hot associating tackifier comparative sample.

[0089] Comparative Example 5

[0090] The present comparative example provides a hot associating tackifier, and the preparation method thereof comprises the following steps:

[0091] The monomers of the alkenyl amide type, N-vinyl formamide 15 g, the monomers of the alkenyl thermosensitive rigid type, 2-acrylamidohexadecane sulfonic acid 15 g, the monomers of the alkenyl sulfonic acid type, methacryl sulfonic acid 30 g, the monomers of the alkenyl cationic type, dimethyldiallyl ammonium chloride 30 g, were dissolved in water to form a mixed monomer solution, and the total concentration of the monomers was 20%. The pH of the solution was adjusted to 7-8 using sodium hydroxide with a concentration of 20%. Nitrogen was bubbled into the system for 30 min at room temperature to replace the air, especially oxygen, in the system. The initiator, azobisdimethylamino propane hydrochloride 0.3 g, was dissolved in water to form a solution, which was slowly added to the mixed monomer solution. The temperature was set to 65°C, and the polymerization reaction was carried out for 8 h. A white viscous product was obtained. The polymer was washed with acetone to remove the unreacted monomers, and then placed in an oven at a temperature of 70°C for drying treatment. After the polymer was completely dried, it was crushed using a crusher to obtain the hot associating tackifier comparative sample.

[0092] Experimental Example 1: Test of temperature resistance and salt resistance

[0093] Preparation of the tackifier solution: 4 g of the tackifier (the hot associating tackifier prepared in each example and comparative example) was added to 400 mL of tap water (fresh water), and 80 g of sodium chloride was added. The mixture was stirred at a high speed of 3000 revolutions per minute using a high-speed mixer.

[0094] The anti-temperature and anti-salt performance evaluation method: the rheological properties of the sample (thickening agent solution) to be tested were determined by using a ZNN-D6 type rotary viscometer at room temperature. 300 ml of the thickening agent solution was taken and placed in an aging tank, which was then placed in a roller oven at 165°C for heat rolling aging for 16 hours. After the heat rolling was completed, the aging tank was naturally cooled to room temperature, and the rheological properties of the solution after heat rolling were determined in the same way. The rotary viscometer was used to test the readings of the sample at 600 and 300 revolutions per minute, and the apparent viscosity (AV), plastic viscosity (PV), dynamic shear force (YP), and viscosity retention rate (R) of the experimental sample were calculated. The specific results are shown in Table 1 below,

[0095] wherein

[0096] In the formula, AV is the apparent viscosity, mPa·s

[0097] PV is the plastic viscosity, mPa·s

[0098] YP is the dynamic shear force, Pa

[0099] R is the viscosity retention rate, %

[0100] Table 1 Anti-temperature and anti-salt performance test results

[0101]

[0102]

[0103] From the data in the above table, it can be seen that compared with the comparative examples, the rheological parameters such as viscosity and shear force of the thickening agent sample solution prepared by the heat associating thickening agent prepared by the present application changed less before and after heat rolling aging at 165°C for 16 hours. The experimental data of Example 9 and Comparative Example 4, and Example 10 and Comparative Example 5 show that: during the synthesis of the thickening agent, too high or too low amount of a certain monomer will affect the anti-temperature and anti-salt performance of the polymer. For example: by reducing the content of the alkenyl thermosensitive rigid body in Example 9 and Comparative Example 4, the temperature-sensitive association behavior of the polymer at high temperature is affected, the thickening property at high temperature is reduced, and thus the viscosity of the polymer decreases rapidly after high temperature heat rolling; in Example 10 and Comparative Example 5, due to the excessive addition of alkenyl cationic monomer, with the increase of aging temperature and aging time, the polymer will undergo hydrolysis, and the addition of excessive cationic groups will destroy the balance of the number of anions and cations in the molecular chain, resulting in a significant reduction in the anti-salt ability and the solution viscosity. The apparent viscosity retention rate of the examples is higher than 60%, and the apparent viscosity retention rate of the comparative examples is lower than 49%, which indicates that the anti-temperature and thickening effect of the heat associating thickening agent prepared by the present application is significantly better than that of the comparative samples, and the heat associating thickening agent has good anti-temperature and anti-salt performance.

[0104] Experimental Example 2: Test of the heat association performance of the thickening agent

[0105] Thermal association performance evaluation method of viscosity enhancer: rheological properties of viscosity enhancer solution sample at different temperatures between 25-165℃ were determined by OFITE high temperature and high pressure rheometer, and the test method referred to national standard GB / T16783.1-2014 "Petroleum and Natural Gas Industry Drilling Fluids Field Testing Part 1: Water-based Drilling Fluids", and then the relevant data were calculated according to formula (1)-(3). The specific test results are shown in Table 2.

[0106] Table 2. Rheological property test results of viscosity enhancer at different temperatures

[0107]

[0108]

[0109]

[0110]

[0111] From the data in the above table, it can be seen that in the test range of 25-165℃, the viscosity enhancer sample provided by the present application shows good viscosity increasing effect and stable rheological property due to its thermal association characteristics, and the rheological parameters such as apparent viscosity, plastic viscosity and dynamic shear force change little with the increase of temperature, while the rheological parameters of the comparative sample decrease obviously with the increase of temperature, which shows that the viscosity enhancer provided by the present application has the advantage of thermal association performance, because the thermal sensitive groups in the viscosity enhancer molecules provided by the present application produce phase change association at high temperature, which can form a strong hydrophobic association network structure, and enhance the high temperature viscosity increasing and temperature resistance of the viscosity enhancer molecules, so the rheological parameters of the viscosity enhancer sample are less affected by temperature.

[0112] Of course, the present application can also have other various embodiments and deformations, and those skilled in the art can make various corresponding changes and deformations according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and deformations should belong to the protection scope of the claims of the present application.

Claims

1. A thermally associative tackifier, characterized in that, The raw materials include the following parts by weight: 10-50 parts of alkenyl amide monomer, 20-50 parts of alkenyl thermosensitive rigid monomer, 20-50 parts of alkenyl sulfonic acid monomer, and 5-20 parts of alkenyl cationic monomer.

2. The thermo-associated tackifier as described in claim 1, characterized in that, The alkenylamide monomer is selected from at least one of acrylamide, N,N-dimethylacrylamide, N-vinylformamide, N-vinylacetamide, and N-hexadecylacrylamide.

3. The thermo-associated tackifier as described in claim 1, characterized in that, The alkenyl thermosensitive rigid monomer is selected from at least one of N-vinylcaprolactam, N-isopropylacrylamide, 2-acrylamidohexadecanesulfonic acid and 2-acrylamidooctadecanesulfonic acid.

4. The thermo-associated tackifier as described in claim 1, characterized in that, The alkenyl sulfonic acid monomer is selected from at least one of propylene sulfonic acid, methyl propylene sulfonic acid, and 2-acrylamide-2-methylpropanesulfonic acid.

5. The thermally associative tackifier according to any one of claims 1-4, characterized in that, The alkenyl cationic monomer is selected from at least one of dimethyl diallyl ammonium chloride, methyl allyl trimethyl ammonium chloride, and methacryloyloxyethyl trimethyl ammonium chloride.

6. A method for preparing the thermally associative tackifier according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Dissolve the alkenyl amide monomer, alkenyl thermosensitive rigid monomer, alkenyl sulfonic acid monomer and alkenyl cationic monomer in water to obtain a mixed monomer solution; S2: Adjust the pH of the mixed monomer solution to neutral using an alkaline solution, then control the system in an oxygen-free atmosphere and add an initiator to initiate the polymerization reaction. After the polymerization reaction is completed, remove the unreacted monomers, dry and pulverize to obtain the thermally associative thickener.

7. The method for preparing the thermally associative tackifier as described in claim 6, characterized in that, The polymerization reaction is carried out at a temperature of 50–80°C for 5–8 hours.

8. The method for preparing the thermally associative tackifier as described in claim 6, characterized in that, The initiator is selected from at least one of ammonium persulfate, potassium persulfate, benzoyl peroxide, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, and azobiscyanopentanoic acid.

9. The method for preparing the thermally associative tackifier as described in claim 8, characterized in that, The amount of the initiator is 0.2% to 0.5% of the total mass of the monomers.

10. The application of the thermally associating thickener according to any one of claims 1-5 or the thermally associating thickener according to any one of claims 6-9 in the field of oilfield chemicals.

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