Non-ionic hydrophobic monomer modified emulsion polymerization high-temperature suspending agent and preparation method thereof

Abstract

The invention relates to the technical field of oil field high-temperature suspending agents, and particularly discloses a nonionic hydrophobic monomer modified emulsion polymerization high-temperature suspending agent and a preparation method thereof. Wherein the component I is a polymerized monomer formed by polymerizing a modified monomer and a hydrophobic monomer; the component II is unsaturated carboxylic acid formed by mixing one or two of butadiene dicarboxylic acid and acrylic acid; the auxiliary agent comprises a pH regulator, styrene, pure water, an oxidation initiator, a reduction initiator, kerosene, an oleophylic emulsifier and a chain transfer agent; the suspending agent has the beneficial effects that the problem that an existing suspending agent is poor in suspending effect in cement slurry at the high temperature can be solved, the stability of the cement slurry at the high temperature is improved, and the highest tolerable temperature of the suspending agent can reach 180 DEG C.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield high-temperature suspension agents, in particular to a nonionic hydrophobic monomer modified emulsion polymerization high-temperature suspension agent and a preparation method thereof. Background Art

[0002] Cementing suspending agent is mainly used to prevent particle sedimentation in oil well cement slurry and is an oil well cement slurry admixture that can enhance the stability of cement slurry system. In the process of oil well cementing, the stability of cement slurry affects the safety of oil well cementing construction and the quality of cementing. When the stability of cement slurry is poor and the particle sedimentation is too much, it will lead to abnormal thickening time of cement slurry, serious stratification in slurry, and poor sealing and spacing between cementing layers. The oil well suspending agents currently used are mainly natural polymers and synthetic polymers. Natural polymer suspending agents, such as sodium bentonite, xanthan gum, carboxymethyl cellulose, etc., have good suspension properties at low temperatures and high viscosity, but the viscosity of such substances drops sharply at high temperatures, and the suspension stability of cement slurry deteriorates, so their use is limited; while synthetic polymer suspending agents can introduce different temperature-resistant monomers and groups through unique molecular design, and even modify the side chains of monomers to further improve their molecular stability. Compared with natural polymer suspending agents, their adaptability and suspension properties are greatly improved, and they can be widely used in cementing.

[0003] At present, with the development in the field of oil well exploitation, oil wells have deeper depths and higher temperatures inside the oil wells. Now the bottom hole temperature can exceed 180°C. Under this condition, the stability of cement slurry in high-temperature deep cementing is difficult to guarantee. The polymer contained in the synthetic polymer suspending agent currently used tends to hydrolyze at high temperatures, and its temperature resistance is relatively poor, which will cause the molecular structure to break, reducing the suspension effect of the suspending agent, thereby not helping the stability of the particles in the cement slurry. Therefore, the suspending agent currently used is not enough to achieve a good suspension effect on the cement slurry in high-temperature deep cementing.

[0004] Therefore, developing a suspending agent with high temperature resistance and a preparation method thereof can solve the problems existing in the existing suspending agents and is of great significance. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art, provide a nonionic hydrophobic monomer modified emulsion polymerization high-temperature suspending agent and a preparation method thereof, and solve the problems that the suspension performance of the existing cement slurry suspending agent deteriorates under high temperature environment, the cement slurry is diluted a lot, its stability is reduced, and the cement particles are greatly settled.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present application provides a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent, which is composed of component one, component two and an auxiliary agent;

[0008] Among them, component one is a polymerized monomer formed by polymerization of a modified monomer and a hydrophobic monomer; component two is an unsaturated carboxylic acid formed by a mixture of one or two of butadiene dicarboxylic acid and acrylic acid; auxiliary agents include a pH regulator, styrene, pure water, an oxidation initiator, a reduction initiator, kerosene, a lipophilic emulsifier, and a chain transfer agent;

[0009] The hydrophobic monomer is N,N ’ -Butylbis[(3-acrylamidopropyl)]dimethylammonium bromide, the structural formula of which is

[0010]

[0011] In one embodiment of the present application, the hydrophobic monomer is prepared by adding a certain amount of N-(3-dimethylaminopropyl)acrylamide into ethanol to dissolve it, and then adding 1,4-dibromobutane and phenothiazine to obtain the hydrophobic monomer after a polymerization reaction.

[0012] In one embodiment of the present application, the modified monomer is one or a mixture of two of N,N'-methylenebisacrylamide, acryloylmorpholine, and acrylamide.

[0013] In one embodiment of the present application, the component one is prepared by uniformly mixing a certain amount of modified monomer, hydrophobic monomer and a certain amount of pure water, and reacting to obtain a polymerized monomer.

[0014] In one embodiment of the present application, the amount of the modified monomer in component one is 2 to 5 times that of the hydrophobic monomer; the unsaturated carboxylic acid in component two accounts for 20% to 50% of the high temperature suspension agent;

[0015] In the auxiliary agent, the amount of pure water is 4 to 10 times the total amount of component one and component two, the amount of pH regulator is 0.5 to 1.5 times the amount of component one and component two, and the pH value can be controlled to be 5 to 7; the amount of kerosene is 0.8 to 1.5 times the mass of pure water; the amount of lipophilic emulsifier accounts for 10% to 20% of the mass of kerosene;

[0016] The amount of styrene is 20%-30% of the total mass of component one and component two; the amount of chain transfer agent is 20%-40% of oxidation initiator; the amount of oxidation initiator is 0.05%-0.2% of the total mass of component one and component two; the amount of reduction initiator is 0.02%-0.15% of the total mass of component one and component two

[0017] In one embodiment of the present application, the pH regulator is sodium carbonate or sodium bicarbonate, and the mass concentration of sodium carbonate or sodium bicarbonate is 95%-98%; the oxidation initiator is potassium persulfate or tert-butyl hydroperoxide; the reduction initiator is sodium bisulfite or sodium pyrosulfite; the lipophilic emulsifier is T-80, and its HLB value is 15; the chain transfer agent is mercaptopropionic acid or mercaptopropanol.

[0018] In a second aspect, the present application provides a method for preparing a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent, comprising the following steps:

[0019] S1: Obtain modified monomers, raw materials for preparing hydrophobic monomers, unsaturated carboxylic acids and auxiliary agents according to the components and set them aside;

[0020] S2: preparing a hydrophobic monomer;

[0021] Obtain N-(3-dimethylaminopropyl) acrylamide and add it to an equal mass of ethanol. After dissolving, add 1,4-dibromobutane and phenothiazine to the solution. Then, after continuous stirring for a certain period of time, rinse the mixed solution with ether. Place the precipitated solid in a drying oven and dry it at about 105°C. The obtained solid is the hydrophobic monomer.

[0022] S3: preparing polymerization monomers;

[0023] Add the modified monomer and the hydrophobic monomer into a certain amount of pure water according to a certain component ratio, mix them evenly, heat them in a water bath at a solution temperature of 80°C ± 2°C, and stir them for reaction, thereby obtaining component 1;

[0024] S4: preparing water phase and oil phase;

[0025] First, the polymerizable monomer obtained in step S3 is added to pure water with a mass of 5 times that of the polymerizable monomer, and then an unsaturated carboxylic acid and a chain transfer agent are added to the mixed solution, and then the solution temperature is controlled not to exceed 40° C., and then sodium carbonate or sodium bicarbonate is added to the mixed solution to make the pH value of the mixed solution 5-7, and the mixture is stirred to obtain an aqueous phase solution; at the same time, kerosene, a lipophilic emulsifier, a polymerizable monomer and styrene are obtained according to a mass ratio and are set aside; at room temperature, the lipophilic emulsifier and styrene are dissolved in kerosene, and the mixture is stirred to obtain an oil phase solution;

[0026] S5: preparing a pre-emulsion;

[0027] After the temperature is controlled at 30°C-40°C, the aqueous phase solution prepared in step S4 is mixed with the oil phase solution and uniformly emulsified for a certain period of time; the temperature is maintained constant, and a chain transfer agent and an oxidation initiator are added to obtain a pre-emulsion of the suspension agent;

[0028] S6: preparing an aqueous emulsion;

[0029] The pre-emulsion is stirred and heated in a water bath to 65°C-75°C, a reduction initiator is added dropwise to the pre-emulsion, and then stirred for a certain period of time to obtain an aqueous emulsion of the suspension;

[0030] S7: preparing a suspension;

[0031] First, the aqueous emulsion obtained in step S6 is placed in a freezer and frozen at about -50°C for 1-1.5 hours until the aqueous emulsion is completely frozen; then the aqueous emulsion after freezing is sent to a drying chamber, the temperature is set at -20°C-+20°C, and the drying time is about 8 to 10 hours; after drying, a suspension is obtained, and finally the obtained suspension solid is placed in a material crusher for crushing, so that the particle size of the suspension is less than 10% when the residue passes the 0.315mm sieve.

[0032] Principle: The present invention has developed a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent, in which a nonionic hydrophobic monomer is synthesized, and its name is N,N ’ -Butylbis[(3-acrylamidepropyl)]dimethylammonium bromide has a stable long-chain molecular structure. Ionic bonds (such as N-Br bonds) in the molecular structure and amide groups (-CONH-) in the molecule form hydrogen bonds, which can resist breaking at high temperatures. The carried groups further enhance the interaction between molecules and can improve the thermal stability of the compound. Both ends of the molecular chain have double bonds, which form a ring structure when polymerized with acrylamide derivatives, thereby making the molecular structure more stable. The suspension agent prepared by using the hydrophobic monomer as one of the components can withstand high temperatures. In an environment where the bottom temperature reaches 180°C, the high-temperature suspension agent of the present invention is added to cement slurry and is not affected by the high temperature. The suspension agent can play a relatively good suspension role in cement slurry in a high-temperature state, so that cement slurry particles do not settle.

[0033] The present invention has the following advantages:

[0034] (1) This scheme synthesizes a hydrophobic monomer, which has a stable long-chain molecular structure, can maintain its chemical properties unchanged at high temperatures, and can enhance the thermal stability of the compound; compared with the cement slurry suspending agent on the market, the solution viscosity of the suspending agent in the cement slurry under high temperature environment will decrease due to the high temperature, resulting in poor suspension performance; the suspending agent of the present invention prepared by using the hydrophobic monomer as one of the ingredients is added to the cement slurry. Under high temperature environment, it is resistant to high temperature in the cement slurry and has better suspension performance;

[0035] (2) The raw materials of the present invention are easily available, the polymerization reaction between the monomers is sufficient, the performance is stable and the conversion rate is high;

[0036] (3) The suspension prepared by the present invention adopts an unconventional polymer polymerization method, and the molecular weight distribution of the obtained suspension is uniform. Unlike the free radical polymerization method of aqueous solution, the product molecular weight fluctuation can be avoided, which is difficult to control well.

[0037] (4) The vacuum freeze-drying method is used to prepare the solid particles of the suspension, which reduces the impact of drying on the performance of the suspension and can maximize the original molecular structure of the suspension. DETAILED DESCRIPTION

[0038] The present invention is further described below, but the protection scope of the present invention is not limited to the following description.

[0039] It should be noted that, in order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] At present, with the development in the field of oil well exploitation, oil wells have deeper depths and higher temperatures inside the wells. Now the bottom hole temperature can exceed 180°C. Under this condition, the stability of cement slurry in high-temperature deep cementing is difficult to guarantee. The polymer contained in the synthetic polymer suspending agent currently used tends to hydrolyze at high temperatures, and its temperature resistance is relatively poor, which will cause the molecular structure to break, reducing the suspension effect of the suspending agent, thereby not helping the stability of the particles in the cement slurry. Therefore, the suspending agent currently used cannot play a good suspension effect on the cement slurry in high-temperature deep cementing.

[0041] The nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent prepared by the present invention is mainly prepared by synthesizing a long-chain nonionic hydrophobic monomer, namely N,N ’-Butylbis[(3-acrylamidopropyl)]dimethylammonium bromide replaces 2-acrylamido-2-methylpropanesulfonic acid and the like in conventional suspending agents. The hydrophobic monomer has a relatively stable long-chain molecular structure and can keep its chemical properties unchanged at high temperatures. The ionic bonds (such as N-Br bonds) in the molecules and the amide groups (-CONH-) in the molecules form hydrogen bonds, which can resist breaking at high temperatures. The carried groups further enhance the interaction force between molecules and improve the thermal stability of the compound. The presence of complex macromolecular chains can aggregate through hydrophobic association to form a supramolecular structure dominated by intermolecular association, resulting in an increase in the fluid mechanics volume and a significant increase in the solution viscosity. The suspending agent prepared by using the hydrophobic monomer as a component can prevent the deterioration of the suspension performance caused by the decrease in the solution viscosity of the suspending agent at high temperatures.

[0042] (Example 1)

[0043] Used for the preparation of a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent.

[0044] The components for preparing the suspension concentrate are as follows: 30 g of a hydrophobic monomer, 60 g of a modified monomer (i.e., N,N'-methylenebisacrylamide), 18 g of an unsaturated carboxylic acid (i.e., butadiene dicarboxylic acid), 0.002 g of a chain transfer agent (i.e., mercaptopropionic acid), 0.1 g of an oxidative initiator (i.e., potassium persulfate), 0.08 g of a reductive initiator (i.e., sodium bisulfite), 21.6 g of styrene, 10 g of kerosene, and 1 g of a lipophilic emulsifier T-80.

[0045] First, 20 g of N-(3-dimethylaminopropyl) acrylamide was weighed and added to an equal amount of ethanol to dissolve to obtain a solution. Then, 26 g of 1,4-dibromobutane and 5 g of phenothiazine were added to the solution. After stirring for two hours with a stirring rod, the solution was repeatedly rinsed with ether and the precipitated solid was dried at 105 ° C to obtain 30 g of the hydrophobic monomer (i.e., N,N ’ -butylenebis[(3-acrylamidopropyl)]dimethylammonium bromide);

[0046] Then, the hydrophobic monomer and the modified monomer are added to 150g of pure water and stirred. The container is placed in a water bath to heat the solution to 80°C±1°C and stirred for two hours at this temperature. The solution is then transferred to a container with a larger capacity, and 1200g of pure water, unsaturated carboxylic acid and chain transfer agent are added thereto. Sodium carbonate aqueous solution is added to the solution to adjust the pH value of the solution to 5.4-5.8. After the pH value of the solution is adjusted, the solution is an aqueous phase solution. The oil phase solution needs to weigh 10g of kerosene and 10g of pure water, mix them, and keep stirring. The lipophilic emulsifier T-80 and styrene are added thereto at room temperature, and the oil phase solution is obtained after sufficient stirring.

[0047] The oil phase solution and the aqueous phase solution are mixed with each other, stirred and emulsified for 0.5h-1h, and the system temperature is maintained at about 30℃-40℃. An oxidizing initiator is added to the mixed solution. After the addition is completed, high-speed shear emulsification is performed for 10min-15min. After the emulsification is completed, the temperature is raised to 70℃±1℃ in a water bath, and the reducing initiator is added and maintained at 70℃±1℃ for two hours to obtain an aqueous emulsion. The aqueous emulsion is passed into a freezing chamber through a pipeline for freezing. After the material in the freezing chamber is completely frozen, it is transferred to a drying chamber for sublimation drying. After complete drying and crushing, a non-ionic hydrophobic monomer modified emulsion polymerization high-temperature suspension agent is obtained.

[0048] It should be noted that the finally obtained suspension solid is placed in a material crusher for crushing so that the particle size thereof passes through a 0.315 mm sieve with a residue less than 10%.

[0049] It should be noted that when adding sodium carbonate aqueous solution to adjust the pH value, the solution temperature is controlled not to exceed 40°C during the process, so it needs to be added slowly to avoid the solution temperature rising due to heat release caused by the acid-base neutralization reaction during the process.

[0050] It should be noted that the container for holding the solution is a three-necked flask of suitable capacity.

[0051] (Example 2)

[0052] Used for the preparation of a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent.

[0053] The components for preparing the suspension agent are specifically: 60 g of a hydrophobic monomer, 180 g of a modified monomer (i.e., N,N'-methylenebisacrylamide), 84 g of an unsaturated carboxylic acid (i.e., acrylic acid), 0.01 g of a chain transfer agent (i.e., mercaptopropanol), 0.3 g of an oxidative initiator (i.e., tert-butyl hydroperoxide), 0.2 g of a reducing initiator (sodium metabisulfite), 60 g of styrene, 30 g of kerosene, and 3.5 g of a lipophilic emulsifier T-80.

[0054] First, 100 g of N-(3-dimethylaminopropyl) acrylamide was weighed and added to an equal amount of ethanol to dissolve to obtain a solution. Then, 130 g of 1,4-dibromobutane and 25 g of phenothiazine were added to the solution. After stirring for two hours with a stirring rod, the solution was repeatedly rinsed with ether and the precipitated solid was dried at 105 ° C to obtain 60 g of the hydrophobic monomer (i.e., N,N ’ -butylenebis[(3-acrylamidopropyl)]dimethylammonium bromide);

[0055] Then, the hydrophobic monomer and the modified monomer are added to 1680g of pure water and stirred. The container is placed in a water bath to heat the solution to 80°C±1°C and stirred for two hours at this temperature. The solution is then transferred to a container with a larger capacity, and 1500g of pure water, unsaturated carboxylic acid and chain transfer agent are added thereto. Sodium carbonate aqueous solution is added to the solution to adjust the pH value of the solution to 6.0-6.5. After the pH value of the solution is adjusted, the solution is an aqueous phase solution. The oil phase solution needs to weigh 10g of kerosene and 10g of pure water, mix them, and keep stirring. The lipophilic emulsifier T-80 and styrene are added thereto at room temperature, and the oil phase solution is obtained after sufficient stirring.

[0056] The oil phase solution and the aqueous phase solution are mixed with each other, stirred and emulsified for 0.5h-1h, and the system temperature is maintained at about 30℃-40℃. An oxidizing initiator is added to the mixed solution. After the addition is completed, high-speed shear emulsification is performed for 10min-15min. After the emulsification is completed, the temperature is raised to 75℃±1℃ in a water bath, and the reducing initiator is added and maintained at 75℃±1℃ for two hours to obtain an aqueous emulsion. The aqueous emulsion is passed through a pipeline into a freezing chamber for freezing. After the material in the freezing chamber is completely frozen, it is transferred to a drying chamber for sublimation drying. After complete drying and crushing, a non-ionic hydrophobic monomer modified emulsion polymerization high-temperature suspension agent is obtained.

[0057] (Example 3)

[0058] Used for the preparation of a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent.

[0059] The components for preparing the suspension concentrate are specifically as follows: 60 g of a hydrophobic monomer, 250 g of a modified monomer (i.e., a mixture of acryloylmorpholine and acrylamide), wherein the ratio of acryloylmorpholine to acrylamide is 3:2; 100 g of an unsaturated carboxylic acid (i.e., a mixture of butadiene dicarboxylic acid and acrylic acid), wherein the ratio of butadiene dicarboxylic acid to acrylic acid is 1:1; 0.05 g of a chain transfer agent (i.e., mercaptopropanol), 0.5 g of an oxidation initiator (i.e., tert-butyl hydroperoxide), 0.4 g of a reduction initiator (i.e., sodium pyrosulfite), 75 g of styrene, 35 g of kerosene, and 3.5 g of a lipophilic emulsifier T-80.

[0060] First, 100 g of N-(3-dimethylaminopropyl) acrylamide was weighed and added to an equal amount of ethanol to dissolve to obtain a solution. Then, 130 g of 1,4-dibromobutane and 25 g of phenothiazine were added to the solution. After stirring for two hours with a stirring rod, the solution was repeatedly rinsed with ether and the precipitated solid was dried at 105 ° C to obtain 60 g of the hydrophobic monomer (i.e., N,N ’ -butylenebis[(3-acrylamidopropyl)]dimethylammonium bromide);

[0061] Then, add the hydrophobic monomer and the modified monomer to 1400g of pure water and stir, place the container in a water bath to heat the solution to 80°C±1°C, and continue stirring for two hours under this temperature environment, then transfer the solution to a container with a larger capacity, add 1000g of pure water, unsaturated carboxylic acid and chain transfer agent; add sodium carbonate aqueous solution to the solution to adjust the pH value of the solution to 6.0-6.5, after the pH adjustment of the solution is completed, it is an aqueous phase solution; the oil phase solution needs to weigh 35g of kerosene and 35g of pure water, mix, and keep stirring, add lipophilic emulsifier T-80 and styrene to the inside at room temperature, and obtain an oil phase solution after sufficient stirring;

[0062] The oil phase solution and the aqueous phase solution are mixed with each other, stirred and emulsified for 0.5h-1h, and the system temperature is maintained at about 30℃-40℃. An oxidizing initiator is added to the mixed solution. After the addition is completed, high-speed shear emulsification is performed for 10min-15min. After the emulsification is completed, the temperature is raised to 80℃±1℃ in a water bath, and after the reducing initiator is added, the temperature is maintained at 80℃±1℃ for two hours to obtain an aqueous emulsion. The aqueous emulsion is passed into a freezing chamber through a pipeline for freezing. After the material in the freezing chamber is completely frozen, it is transferred to a drying chamber for sublimation drying. After complete drying and crushing, a non-ionic hydrophobic monomer modified emulsion polymerization high-temperature suspension agent is obtained.

[0063] (Comparative Example 1)

[0064] Based on Examples 1-3, the non-ionic modified emulsion polymerization high temperature suspension agent of the present invention is prepared without adding hydrophobic monomers and keeping other components unchanged.

[0065] The components for preparing the suspension agent are specifically: 60g of modified monomer (i.e. N,N'-methylenebisacrylamide), 18g of unsaturated carboxylic acid (i.e. butadiene dicarboxylic acid), 0.002g of chain transfer agent (i.e. mercaptopropionic acid), 0.1g of oxidation initiator (i.e. potassium persulfate), 0.08g of reduction initiator (i.e. sodium bisulfite), 21.6g of styrene, 10g of kerosene, and 1g of lipophilic emulsifier T-80.

[0066] First, add the modified monomer to 150g of pure water and stir it. Place the container in a water bath to heat the solution to 80℃±1℃ and continue stirring for two hours at this temperature. Then transfer the solution to a container with a larger capacity, add 1200g of pure water, unsaturated carboxylic acid and chain transfer agent. Add sodium carbonate aqueous solution to the solution to adjust the pH value of the solution to 5.4-5.8. After the pH adjustment of the solution is completed, it is an aqueous phase solution. For the oil phase solution, weigh 10g of kerosene and 10g of pure water and mix them. Keep stirring. Add lipophilic emulsifier T-80 and styrene to the inside at room temperature. After sufficient stirring, an oil phase solution is obtained.

[0067] The oil phase solution and the aqueous phase solution are mixed with each other, stirred and emulsified for 0.5h-1h, and the system temperature is maintained at about 30℃-40℃. An oxidizing initiator is added to the mixed solution. After the addition is completed, high-speed shear emulsification is performed for 10min-15min. After the emulsification is completed, the temperature is raised to 75℃±1℃ in a water bath, and after the reducing initiator is added, the temperature is maintained at 75℃±1℃ for two hours to obtain an aqueous emulsion. The aqueous emulsion is passed into a freezing chamber through a pipeline for freezing. After the material in the freezing chamber is completely frozen, it is transferred to a drying chamber for sublimation drying, and is obtained after being completely dried and crushed.

[0068] (Comparative Example 2)

[0069] A high molecular polymer and a preparation method thereof.

[0070] Among them, the specific components for preparing the high molecular polymer are: 25g of 2-acrylamide-2-methylpropanesulfonic acid, 9g of acryloylmorpholine, 12g of acrylic acid, 240g of deionized water, 0.1g of dodecyl mercaptan, 15g of sodium hydroxide, 0.05g of oxidation initiator potassium peroxide, and 0.04g of reduction initiator sodium bisulfite.

[0071] First, 2-acrylamide-2-methylpropanesulfonic acid, acryloylmorpholine and acrylic acid are weighed and mixed with water to obtain a mixed solution A, which is stirred, and then sodium hydroxide and water are weighed to prepare a 20% alkaline solution as a pH regulator, and the pH regulator is added to the mixed solution A to adjust the pH value to 5.4-5.8 to obtain a mixed solution B; then initiator potassium peroxide and sodium bisulfite are weighed and mixed to obtain an initiator solution, and the mixed solution B is heated to 70°C±1°C, and then 0.1g of dodecyl mercaptan is added to the mixed solution B according to the prepared components, and then the initiator solution is slowly added dropwise to the mixed solution B, and the temperature is maintained at 70°C±1°C. After the reaction is kept warm for three hours, a semi-finished polymer suspension is obtained; finally, the semi-finished polymer suspension is sent to a vacuum freezing device for drying and crushing, and then a finished polymer suspension is obtained.

[0072] Performance Test:

[0073] Product performance test of Example 1

[0074] Based on the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent prepared in Example 1, it was added to the cement slurry. It should be noted that the test cement slurry was configured according to the relevant content of GB / T19139-2012 oil well cement according to different temperatures. After the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent was added to the cement slurry, the differences in the free liquid of the cement slurry, the normal high temperature rheology, the fluidity, the sedimentation density difference of the cement slurry at 90°C and other properties were measured, as shown in Table 1.

[0075] 100℃ cement slurry basic formula: 100% G-grade oil well cement + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 1 + 3% fluid loss additive + 1% drag reducer FS-13L + 0.5% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0076] 130℃ cement slurry basic formula: 100% G-grade oil well cement + 35% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 1 + 4% fluid loss additive + 1% drag reducer FS-13L + 0.8% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0077] 180℃ cement slurry basic formula: 100% G-grade oil well cement + 80% silica fume + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + X%

[0078] In Example 1, the suspension agent + water + 5% fluid loss additive + 2% drag reducer FS-13L + 4% retarder HX-36L + 0.2% defoamer DF-A was prepared, with a density of 1.88 g / cm 3 ; Among them, the mass percentage of each component is calculated based on the weight of GB / T19139-2012 oil well cement.

[0079] Table 1 Example 1 Product Performance Test

[0080]

[0081] Based on the data in Table 1, it can be seen that in the experimental temperature range of 100°C to 180°C, the cement slurry to which the suspending agent prepared in Example 1 is added has a free liquid of substantially zero after high temperature curing and room temperature placement for 2 hours. The sedimentation density difference of the cement slurry at 90°C is also relatively small, less than 0.02 g / cm 3In summary, the high-temperature stability of cement slurry is better after the addition of the suspending agent. Therefore, the suspending agent prepared in Example 1 can solve the technical problems of conventional suspending agents being easily diluted at high temperatures, having poor stability, and having serious sedimentation of cement slurry particles.

[0082] Product performance test of Example 2

[0083] Based on the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent prepared in Example 2, it was added to the cement slurry. It should be noted that the test cement slurry was configured according to the relevant content of GB / T19139-2012 oil well cement according to different temperatures. After adding the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent to the cement slurry, the differences in the free liquid of the cement slurry, the normal high temperature rheology, the fluidity, the sedimentation density difference of the cement slurry at 90°C and other properties were measured, as shown in Table 2.

[0084] 100℃ cement slurry basic formula: 100% G-grade oil well cement + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 2 + 3% fluid loss additive + 1% drag reducer FS-13L + 0.5% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0085] 130℃ cement slurry basic formula: 100% G-grade oil well cement + 35% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 2 + 4% fluid loss additive + 1% drag reducer FS-13L + 0.8% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0086] 180℃ cement slurry basic formula: 100% G-grade oil well cement + 80% silica fume + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + X%

[0087] In Example 2, the suspension agent + water + 5% fluid loss additive + 2% drag reducer FS-13L + 4% retarder HX-36L + 0.2% defoamer DF-A was prepared, with a density of 1.88 g / cm 3 ; Among them, the mass percentage of each component is calculated based on the weight of GB / T19139-2012 oil well cement.

[0088] Table 2 Example 2 Product Performance Test

[0089]

[0090] Based on the data in Table 2, as the experimental temperature rises to 180°C, the rheological reading of the cement slurry to which the suspending agent prepared in Example 1 is added becomes slightly larger at high temperature, indicating that the cement slurry has not been diluted after high-temperature curing. The free liquid is basically 0 after being placed at room temperature for 2 hours, and the sedimentation density difference of the cement slurry at 90°C is also relatively small. In summary, the high-temperature stability of the cement slurry is better after the suspending agent is added. Therefore, the suspending agent of the present invention can solve the technical problems that conventional suspending agents are easily diluted at high temperatures, have poor stability, and have serious sedimentation of cement slurry particles.

[0091] Product performance test of Example 3

[0092] Based on the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent prepared in Example 3, it was added to the cement slurry. It should be noted that the test cement slurry was configured according to the relevant content of GB / T19139-2012 oil well cement according to different temperatures. After adding the nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent to the cement slurry, the differences in the free liquid of the cement slurry, the normal high temperature rheology, the fluidity, the sedimentation density difference of the cement slurry at 90°C and other properties were measured, as shown in Table 3.

[0093] 100℃ cement slurry basic formula: 100% G-grade oil well cement + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 3 + 3% fluid loss additive + 1% drag reducer FS-13L + 0.5% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0094] 130℃ cement slurry basic formula: 100% G-grade oil well cement + 35% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in Example 3 + 4% fluid loss additive + 1% drag reducer FS-13L + 0.8% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0095] 180℃ cement slurry basic formula: 100% G-grade oil well cement + 80% silica fume + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + X% suspending agent prepared in Example 3 + water + 5% fluid loss additive + 2% drag reducer FS-13L + 4% retarder HX-36L + 0.2% defoamer DF-A, density 1.88g / cm 3 ; Among them, the mass percentage of each component is calculated based on the weight of GB / T19139-2012 oil well cement.

[0096] Table 3 Example 3 Product Performance Test

[0097]

[0098] Based on the data in Table 3, it is known that as the experimental temperature rises to a high temperature of 180°C, the rheological reading of the cement slurry to which the suspending agent prepared in Example 1 is added becomes slightly larger at a high temperature, indicating that the cement slurry has not been diluted after high-temperature curing, and its free liquid is basically 0. At 90°C, the sedimentation density difference of the cement slurry is also relatively small. In summary, after the addition of the suspending agent, the high-temperature stability of the cement slurry is relatively good. Therefore, the suspending agent prepared in Example 3 can solve the technical problems of conventional suspending agents being easily diluted at high temperatures, having poor stability, and having serious sedimentation of cement slurry particles.

[0099] Product performance test of comparative example 1

[0100] Based on the suspension agent without adding hydrophobic monomer prepared in Comparative Example 1, it was added to the cement slurry. It should be noted that according to different temperatures, the test cement slurry was configured in accordance with the relevant content of GB / T19139-2012 oil well cement. The differences in the free liquid, normal high temperature rheology, fluidity, and sedimentation density difference of the cement slurry at 90°C after adding the suspension agent without adding hydrophobic monomer to the cement slurry were measured, as shown in Table 4.

[0101] 100℃ cement slurry basic formula: 100% G-grade oil well cement + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in comparative example 1 + 3% fluid loss additive + 1% drag reducer FS-13L + 0.5% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0102] 130℃ cement slurry basic formula: 100% G-grade oil well cement + 35% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% suspending agent prepared in comparative example 1 + 4% fluid loss additive + 1% drag reducer FS-13L + 0.8% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0103] 180℃ cement slurry basic formula: 100% G-grade oil well cement + 80% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + X% suspending agent prepared in comparative example 1 + water + 5% fluid loss additive + 2% drag reducer FS-13L + 4% retarder HX-36L + 0.2% defoamer DF-A, density 1.88g / cm 3 ; Among them, the mass percentage of each component is calculated based on the weight of GB / T19139-2012 oil well cement.

[0104] Table 4 Comparative Example 1 Product Performance Test

[0105]

[0106] Based on the product performance test of Comparative Example 1 in Table 4, it is known that the suspension prepared in Comparative Example 1 does not contain any hydrophobic monomer (i.e., N, N ’ -butylenebis[(3-acrylamidopropyl)]dimethylammonium bromide), the prepared suspending agent lost the support of the long chain structure in the polymer molecular structure, resulting in insufficient rigidity of the molecular chain. Therefore, as the experimental temperature increased from 100°C to 180°C, the dilution of the cement slurry was more obvious, and the sedimentation density difference at 90°C was as high as 0.40g / cm 3 Moreover, the free liquid of the cement slurry is relatively large, and its rheological properties at high temperature are also reduced. In summary, the suspending agent of the present invention without adding a hydrophobic monomer has a relatively weak high temperature resistance and a relatively poor suspension effect.

[0107] Product performance test of comparative example 2

[0108] Based on a high molecular polymer prepared in Comparative Example 2, it was added to the cement slurry. It should be noted that the test cement slurry was configured according to the relevant content of GB / T19139-2012 oil well cement at different temperatures. The differences in the properties of the cement slurry free liquid, normal high temperature rheology, fluidity, and cement slurry sedimentation density difference at 90°C after adding the high molecular polymer to the cement slurry were measured, as shown in Table 5.

[0109] 100℃ cement slurry basic formula: 100% G-grade oil well cement + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% high molecular polymer prepared in comparative example 2 + 3% fluid loss reducer + 1% drag reducer FS-13L + 0.5% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0110] 130℃ cement slurry basic formula: 100% G-grade oil well cement + 35% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + water + X% high molecular polymer prepared in comparative example 2 + 4% fluid loss additive + 1% drag reducer FS-13L + 0.8% retarder HX-36L + 0.2% defoamer DF-A, density is 1.90g / cm 3 ;

[0111] 180℃ cement slurry basic formula: 100% G-grade oil well cement + 80% silica powder + 5% filler CEA-1 + 2% anti-channeling agent FLOK-2 + X% high molecular polymer prepared in Example 2 + water + 5% fluid loss additive + 2% drag reducer FS-13L + 4% retarder HX-36L + 0.2% defoamer DF-A, density 1.88g / cm 3 ; Among them, the mass percentage of each component is calculated based on the weight of GB / T19139-2012 oil well cement.

[0112] Table 5 Comparative Example 2 Product Performance Test

[0113]

[0114] Based on the product performance test of Comparative Example 2 in Table 5, it is known that the high molecular polymer prepared in Comparative Example 2 uses conventional synthetic monomers, such as 2-acrylamide-2-methylpropanesulfonic acid, acryloylmorpholine, acrylic acid, etc. to prepare the product, and the synthesis technology used is conventional aqueous solution free radical polymerization, which is the same as or very similar to the raw materials used for cement slurry suspending agents in the current industry. From the experimental data in Table 5, it is known that as the experimental temperature increases from 100°C to 180°C, the dilution degree of the cement slurry is obvious, and its sedimentation density difference at 90°C is as high as 0.47g / cm 3 , and there is a lot of free liquid, and the rheological properties at a high temperature of 180°C are low. In summary, the high molecular polymer prepared in Comparative Example 2 has a poor suspension effect as a cement slurry suspending agent. Therefore, when the current drilling depth becomes larger, the deeper the drilling, the higher the temperature, and the suspending agent cannot reflect the suspension effect in the cement slurry under a high temperature environment.

[0115] It can be seen from Tables 1 to 5 that the nonionic hydrophobic monomer modified emulsion polymerization high-temperature suspending agent prepared in the present invention can effectively improve the suspension stability of cement slurry under high temperature environment, keep cement particles suspended, reduce the sedimentation density difference, and make the density difference of cement stone column segments less than 0.02 g / cm 3 At the same time, it can control the fluidity of cement slurry.

[0116] It can be seen from Tables 1 to 3 and 4 that whether to add a hydrophobic monomer to the suspending agent of the present invention is one of the keys to improving the suspension stability of cement slurry at high temperatures. The molecular chain of the non-ionic modified emulsion polymerization high-temperature suspending agent with the addition of a hydrophobic monomer is more rigid, has a higher high temperature resistance, can maintain the stability of cement slurry at high temperatures, slightly thickens the high-temperature rheological properties of cement slurry, and its fluidity is not affected.

[0117] It can be seen from Tables 1 to 3 and 5 that the conventional polymerized monomers used in Comparative Example 2, polymers prepared from 2-acrylamide-2-methylpropanesulfonic acid, acryloylmorpholine, acrylic acid, etc., are used as suspending agents for cement slurry. The components of the suspending agents currently used in the market are the same or similar. This suspending agent does not have strong high temperature resistance and high suspension performance. The decomposition temperature of its molecules is low, less than 130°C. Under high temperature conditions, the molecular structure of the suspending agent breaks, thereby losing its suspension ability, resulting in more dilution of the cement slurry, reduced stability, and significant sedimentation of cement particles. The suspending agent prepared from conventional polymerized monomers cannot suspend the cement slurry under high temperature conditions.

[0118] The above embodiments only express preferred implementation modes, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A nonionic hydrophobic monomer modified emulsion polymerization high temperature suspending agent, characterized in that: It consists of component one, component two and auxiliary agents; Among them, component one is a polymerized monomer formed by polymerization of a modified monomer and a hydrophobic monomer; component two is an unsaturated carboxylic acid formed by a mixture of one or two of butadiene dicarboxylic acid and acrylic acid; auxiliary agents include a pH regulator, styrene, pure water, an oxidation initiator, a reduction initiator, kerosene, a lipophilic emulsifier, and a chain transfer agent; The hydrophobic monomer is N,N ’ -Butylbis[(3-acrylamidopropyl)]dimethylammonium bromide, the structural formula of which is 2. A nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent according to claim 1, characterized in that: The hydrophobic monomer is prepared by adding a certain amount of N-(3-dimethylaminopropyl) acrylamide into ethanol to dissolve it, and then adding 1,4-dibromobutane and phenothiazine to obtain the hydrophobic monomer after a polymerization reaction.

3. A nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent according to claim 1, characterized in that: The modified monomer is one or a mixture of N,N'-methylenebisacrylamide, acryloylmorpholine and acrylamide.

4. The nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent according to claim 1, characterized in that: The first component is prepared by uniformly mixing a certain amount of modified monomer, hydrophobic monomer and a certain amount of pure water, and reacting to obtain a polymerized monomer.

5. A nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent according to claim 4, characterized in that: In component one, the amount of the modified monomer is 2 to 5 times that of the hydrophobic monomer; in component two, the unsaturated carboxylic acid accounts for 20% to 50% of the high-temperature suspension agent; In the auxiliary agent, the amount of pure water is 4 to 10 times the total amount of component one and component two, the amount of pH regulator is 0.5 to 1.5 times the amount of component one and component two, and the pH value can be controlled to be 5 to 7; the amount of kerosene is 0.8 to 1.5 times the mass of pure water; the amount of lipophilic emulsifier accounts for 10% to 20% of the mass of kerosene; The amount of styrene accounts for 20%-30% of the total mass of component one and component two; the amount of chain transfer agent accounts for 20%-40% of oxidation initiator; the amount of oxidation initiator is 0.05%-0.2% of the total mass of component one and component two; the amount of reduction initiator is 0.02%-0.15% of the total mass of component one and component two.

6. A nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent according to claim 5, characterized in that: The pH regulator is sodium carbonate or sodium bicarbonate, and the mass concentration of sodium carbonate or sodium bicarbonate is 95%-98%; the oxidation initiator is potassium persulfate or tert-butyl hydroperoxide; the reduction initiator is sodium bisulfite or sodium pyrosulfite; the lipophilic emulsifier is T-80, and its HLB value is 15; and the chain transfer agent is mercaptopropionic acid or mercaptopropanol.

7. A method for preparing a nonionic hydrophobic monomer modified emulsion polymerization high temperature suspension agent as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Obtain modified monomers, raw materials for preparing hydrophobic monomers, unsaturated carboxylic acids and auxiliary agents according to the components and set them aside; S2: preparing a hydrophobic monomer; Obtain N-(3-dimethylaminopropyl) acrylamide and add it to an equal mass of ethanol. After dissolving, add 1,4-dibromobutane and phenothiazine to the solution. Then, after continuous stirring for a certain period of time, rinse the mixed solution with ether. Place the precipitated solid in a drying oven and dry it at about 105°C. The obtained solid is the hydrophobic monomer. S3: preparing polymerization monomers; Add the modified monomer and the hydrophobic monomer into a certain amount of pure water according to a certain component ratio, mix them evenly, heat them in a water bath at a solution temperature of 80°C ± 2°C, and stir them for reaction, thereby obtaining a polymerized monomer; S4: preparing water phase and oil phase; First, the polymerizable monomer obtained in step S3 is added to pure water with a mass of 5 times that of the polymerizable monomer, and then an unsaturated carboxylic acid and a chain transfer agent are added to the mixed solution, and then the solution temperature is controlled not to exceed 40° C., and then sodium carbonate or sodium bicarbonate is added to the mixed solution to make the pH value of the mixed solution 5-7, and the mixture is stirred to obtain an aqueous phase solution; at the same time, kerosene, a lipophilic emulsifier, a polymerizable monomer and styrene are obtained according to a mass ratio and are set aside; at room temperature, the lipophilic emulsifier and styrene are dissolved in kerosene, and the mixture is stirred to obtain an oil phase solution; S5: preparing a pre-emulsion; After the temperature is controlled at 30°C-40°C, the aqueous phase solution prepared in step S4 is mixed with the oil phase solution and uniformly emulsified for a certain period of time; the temperature is maintained constant, and a chain transfer agent and an oxidation initiator are added to obtain a pre-emulsion of the suspension agent; S6: preparing an aqueous emulsion; The pre-emulsion is stirred and heated in a water bath to 65°C-75°C, a reduction initiator is added dropwise to the pre-emulsion, and then stirred for a certain period of time to obtain an aqueous emulsion of the suspension; S7: preparing a suspension; First, the aqueous emulsion obtained in step S6 is placed in a freezer and frozen at about -50°C for 1-1.5 hours until the aqueous emulsion is completely frozen; then the aqueous emulsion after freezing is sent to a drying chamber, the temperature is set at -20°C-+20°C, and the drying time is about 8 to 10 hours; after drying, a suspension is obtained, and finally the obtained suspension solid is placed in a material crusher for crushing, so that the particle size passes through a 0.315mm sieve with a residue less than 10%.

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