Low-temperature fluid loss agent and preparation method thereof
By using a specific composition of low-temperature dehydration agent and anhydrous sodium metasilicate, the problem of cement slurry not being thickened at low temperature and low addition amounts and long settling time is solved, and low water loss and rapid strength development is achieved. Improved the early performance of cement slurry.
Patent Information
- Application Number
- CN202411402841.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-01-10
AI Technical Summary
The existing water-depleting agents have poor compatibility with anhydrous sodium metasilicate, resulting in the problem of the cement slurry not thickening, long settling time, and slow strength development at low temperatures and low dosages.
Low temperature water loss agent composed of 2-acrylamide-2-methylpropanesulfonic acid, amide monomer, carboxylic acid monomer, molecular regulator and additive diisopropyl titanate , through specific proportions and preparation methods, good compatibility with anhydrous sodium metasilicate is achieved, shortening cement settling time and improving strength development.
The effect of low water loss at low dose, short cement settling time and rapid strength development is achieved, the performance of conventional water loss agents under low temperature conditions is improved, and the early strength and hardness of cement slurry are enhanced.
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Figure CN119285850A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of low-temperature well cementing, and more specifically to a low-temperature fluid loss reducing agent and a preparation method thereof. Background Art
[0002] At present, silicate G-grade oil well cement is mainly used for cementing. Under low-temperature shallow well conditions, G-grade oil well cement has a long setting time and is very easy to cause oil, gas and water invasion, resulting in a loose cement ring after cementing and poor cementing quality. Therefore, it is particularly important to develop a low-temperature fluid loss reducer and improve the matching cement slurry system to meet the cementing construction under low-temperature conditions.
[0003] Anhydrous sodium metasilicate is often used as a low-temperature early strength agent. Conventional fluid loss agents have the disadvantages of long cement setting time, poor cement slurry thickness, and slow strength development when combined with anhydrous sodium metasilicate at low dosage. This is because when the water-cement ratio of cement is large, the distance between cement particles is large, and anhydrous sodium metasilicate is dispersible. The hydrated colloid will not be enough to fill the gaps between cement particles, resulting in difficulty in controlling water loss. In order to improve the water loss control ability of the fluid loss agent, a large amount of amide or carboxylic acid monomers with strong adsorption capacity are usually introduced. Under alkaline conditions, part of the amide group is hydrolyzed to form a carboxylic acid group. The increase in the carboxylic acid group will lead to an enhanced slow setting performance of the fluid loss agent, a prolonged cement slurry thickening time, slow compressive strength development, and reduced cement stone strength. Therefore, it is particularly important to study a low-dosage fluid loss agent that can be combined with anhydrous sodium metasilicate. Summary of the invention
[0004] To this end, the technical problem to be solved by the present invention is to provide a low-temperature fluid loss reducer and a preparation method thereof, so as to solve the problem that the compatibility of the fluid loss reducer with the low-temperature early strength agent anhydrous sodium metasilicate in the prior art is not good, overcome the shortcomings of cement slurry not being thick enough, cement setting time being long, and strength development being slow under low temperature and low addition conditions, and realize that the compatibility with anhydrous sodium metasilicate can achieve the requirements of low water loss at low addition, short cement setting time, and fast strength development.
[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:
[0006] A low-temperature fluid loss reducing agent is obtained by polymerizing the following components: 2-acrylamide-2-methylpropane sulfonic acid, amide monomers, carboxylic acid monomers, molecular regulators and additives, wherein the additive is di(triethanolamine) diisopropyl titanate.
[0007] The weight proportions of the components of the above-mentioned low-temperature fluid loss reducer are as follows: 80-100 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 10-15 parts by weight of amide monomers, 1-3 parts by weight of carboxylic acid monomers, 3-5 parts by weight of molecular regulators and 4-8 parts by weight of additives.
[0008] In the above-mentioned low-temperature fluid loss reducer, the amide monomer is one or both of acrylamide and N,N-dimethylacrylamide, and the mass ratio of acrylamide to N,N-dimethylacrylamide is 3.0-5.0:1; the carboxylic acid monomer includes one or both of acrylic acid and itaconic acid, and the mass ratio of acrylic acid to itaconic acid is 1.0-2.0:1; and the molecular regulator is isopropanol.
[0009] A method for preparing a low-temperature fluid loss reducing agent comprises the following steps:
[0010] (1) adding water, 2-acrylamide-2-methylpropanesulfonic acid, an amide monomer, a carboxylic acid monomer, and a molecular weight regulator to a three-necked flask equipped with a thermometer and a stirrer to obtain a reaction solution;
[0011] (2) stirring the reaction solution, adjusting the pH to 7, and heating;
[0012] (3) Add initiator and continue the reaction;
[0013] (4) Add additives, stir, dry and crush to obtain a fluid loss reducer.
[0014] In the above-mentioned method for preparing a low-temperature fluid loss reducer, in step (1), the amide monomer is one or both of acrylamide and N,N-dimethylacrylamide; the carboxylic acid monomer includes one or both of acrylic acid and itaconic acid; and the molecular regulator is isopropanol.
[0015] In the preparation method of the low-temperature fluid loss reducer, 2-acrylamide-2-methylpropanesulfonic acid is 80-100 parts by weight, amide monomer is 10-15 parts by weight, carboxylic acid monomer is 1-3 parts by weight, and molecular regulator is 3-5 parts by weight.
[0016] The method for preparing the low-temperature fluid loss reducing agent comprises the following steps: in step (2), stirring the reaction liquid at a speed of 200-300 rpm, adding sodium hydroxide solution to the reaction liquid to adjust the pH to 7, and then raising the temperature of the reaction liquid to 55-60° C.; the mass concentration of the sodium hydroxide solution is 30%. If the temperature is controlled at 55-60° C., the reaction temperature is too high, the reaction is likely to be violent, and the molecular weight becomes small; if the reaction temperature is too low, the induction period is too long, and the molecular weight increases.
[0017] In the above-mentioned method for preparing a low-temperature fluid loss reducing agent, in step (3), the initiator is ammonium persulfate, and after adding 1 part by weight of the initiator, the reaction temperature is controlled to 60° C. and the reaction is carried out at a constant temperature for 4-5 hours.
[0018] In the above-mentioned method for preparing a low-temperature fluid loss agent, in step (4), the additive is diisopropyl di(triethanolamine)titanate, and after adding 4-8 parts by weight of the additive, stirring is continued for 10-15 minutes and then stopped, and the fluid loss agent is obtained after crushing and drying. The additive is added after the polymerization reaction in order to connect to the polymer to form a side chain without changing the original AMPS polymer fluid loss agent, so as to ensure that the formed fluid loss agent has the properties of the additive. If the additive is added together with the monomer, the target polymer product cannot be formed, and the formed fluid loss agent will not have the modified characteristics.
[0019] The preparation method of the above-mentioned low-temperature fluid loss reducing agent comprises the following steps:
[0020] (1) adding 80-100 parts by weight of water, 2-acrylamido-2-methylpropanesulfonic acid, 10-15 parts by weight of an amide monomer, 1-3 parts by weight of a carboxylic acid monomer, and 3-5 parts by weight of a molecular regulator to a three-necked flask equipped with a thermometer and a stirrer to obtain a reaction solution; the amide monomer is one or both of acrylamide and N,N-dimethylacrylamide; the carboxylic acid monomer includes one or both of acrylic acid and itaconic acid; and the molecular regulator is isopropanol;
[0021] (2) stirring the reaction solution at a speed of 200-300 rpm, adding sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 55-60° C.; the mass concentration of the sodium hydroxide solution is 30%;
[0022] (3) adding 1 part by weight of initiator ammonium persulfate to the reaction solution, controlling the reaction temperature to 60° C., and reacting at this constant temperature for 4-5 hours;
[0023] (4) adding 4-8 parts by weight of an additive, wherein the additive is di(triethanolamine)titanate diisopropyl ester, stirring is continued for 10-15 minutes and then stopped, and drying and crushing are performed to obtain a fluid loss additive.
[0024] The technical solution of the present invention achieves the following beneficial technical effects:
[0025] 1. The low-temperature fluid loss reducing agent of the present application can achieve good compatibility with anhydrous sodium metasilicate. When the addition amount in cement is less than 0.5%, the requirements of low water loss, short cement setting time and fast strength development can be achieved.
[0026] 2. The additive added in this application is di(triethanolamine) diisopropyl titanate, and its structure is as follows:
[0027]
[0028] Due to its unique structure, diisopropyl di(triethanolamine)titanate has both coupling and early strength properties. These two properties improve the shortcomings of conventional fluid loss reducers when combined with anhydrous sodium metasilicate at low dosages, such as large filtration loss, long coagulation time, and slow strength development.
[0029] 3. The hydroxyl contained in the structure of di(triethanolamine)titanate diisopropyl is connected to the end of the titanate molecule, and is chemically reacted with the polymer fluid loss reducer to combine, thereby modifying the original fluid loss reducer so that it retains the original fluid loss reducer characteristics and has the characteristics introduced by di(triethanolamine)titanate diisopropyl. Di(triethanolamine)titanate diisopropyl contains short carbon chain alkoxy and nitrogen atoms that can be hydrolyzed. The short chain alkoxy that can be hydrolyzed can react with the surface of inorganic matter to achieve the purpose of chemical coupling. The nitrogen atom contains a pair of unshared electrons, which can enhance the activity of the colloid generated by cement hydration, promote the C3A hydration reaction, and improve the early strength and hardness of cement. Therefore, the modified fluid loss reducer has the advantages of low water loss, short setting time, and fast strength development when combined with anhydrous sodium metasilicate at low dosage (low dosage generally refers to dosage below 0.5%).
[0030] 4. The low-temperature fluid loss agent prepared by the present application does not require the addition of amide or carboxylic acid monomers, and can also inhibit amide hydrolysis. Di(triethanolamine) diisopropyl titanate and AMPS polymer can be bent and entangled to form a micro-crosslinked structure, physically blocking the gaps between cement particles, increasing the viscosity of the cement slurry phase, and thus reducing the filtration rate. The short carbon chain alkoxy and nitrogen atoms contained in the fluid loss agent react with the hydroxide and calcium ions produced by cement hydration, respectively, to increase the surface solubility of cement particles, reduce the concentration of calcium ions and hydroxide in the liquid phase, further promote C3S hydration, shorten the cement setting time, and improve the early strength of cement slurry. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 The thickening curve of cement slurry prepared by the fluid loss reducer prepared in Comparative Document 1 at 33°C;
[0032] Figure 2 Thickening curve of cement slurry prepared with the fluid loss reducer prepared in Example 3 at 33°C. DETAILED DESCRIPTION
[0033] Example 1
[0034] Step 1: Into a three-necked flask equipped with a thermometer and a stirrer, 250 g of water, 100 g of 2-acrylamido-2-methylpropanesulfonic acid, 15 g of acrylamide, 2 g of acrylic acid, and 3 g of isopropanol were added in sequence to obtain a reaction solution.
[0035] Step 2, stirring the reaction solution at a speed of 200 rpm, adding a 30% by mass sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 60° C.;
[0036] Step 3, add 1g of initiator ammonium persulfate to the reaction solution, control the reaction temperature to 60°C, and react at this temperature for 4 hours;
[0037] Step 4: Add 4 g of the additive di(triethanolamine)titanate diisopropyl, continue stirring for 10 min and then stop, dry and crush to obtain a fluid loss additive.
[0038] Example 2
[0039] Step 1. Into a three-necked flask equipped with a thermometer and a stirrer, 300 g of water, 100 g of 2-acrylamido-2-methylpropanesulfonic acid, 10 g of acrylamide, 2 g of N,N-dimethylacrylamide, 1 g of itaconic acid and 4 g of isopropanol were added in sequence to obtain a reaction solution.
[0040] Step 2, stirring the reaction solution at a speed of 200 rpm, adding a 30% by mass sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 60° C.;
[0041] Step 3, add 1g of initiator ammonium persulfate to the reaction solution, control the reaction temperature to 60°C, and react at this temperature for 4 hours;
[0042] Step 4: Add 6 g of the additive di(triethanolamine)titanate diisopropyl, continue stirring for 10 min and then stop, dry and crush to obtain a fluid loss additive.
[0043] Embodiment 3,
[0044] Step 1: Into a three-necked flask equipped with a thermometer and a stirrer, 300 g of water, 100 g of 2-acrylamido-2-methylpropanesulfonic acid, 8 g of acrylamide, 2 g of N,N-dimethylacrylamide, 3 g of acrylic acid, and 5 g of isopropanol were added in sequence to obtain a reaction solution.
[0045] Step 2, stirring the reaction solution at a speed of 300 rpm, adding a 30% by mass sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 60° C.;
[0046] Step 3, add 1g of initiator ammonium persulfate to the reaction solution, control the reaction temperature to 60°C, and react at this temperature for 4 hours;
[0047] Step 4: Add 8 g of the additive di(triethanolamine)titanate diisopropyl, continue stirring for 10 min and then stop, dry and crush to obtain a fluid loss additive.
[0048] Embodiment 4,
[0049] Step 1: Into a three-necked flask equipped with a thermometer and a stirrer, 250 g of water, 100 g of 2-acrylamido-2-methylpropanesulfonic acid, 8 g of acrylamide, 4 g of N,N-dimethylacrylamide, 3 g of acrylic acid, and 5 g of isopropanol were added in sequence to obtain a reaction solution.
[0050] Step 2, stirring the reaction solution at a speed of 200 rpm, adding a 30% by mass sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 60° C.;
[0051] Step 3, add 1g of initiator ammonium persulfate to the reaction solution, control the reaction temperature to 60°C, and react at this temperature for 4 hours;
[0052] Step 4: add 10 g of the additive di(triethanolamine)titanate diisopropyl, continue stirring for 10 min and then stop, dry and crush to obtain a fluid loss additive.
[0053] Comparative Example (Comparative Example is based on Example 2 without adding additives.)
[0054] Step 1. Into a three-necked flask equipped with a thermometer and a stirrer, 300 g of water, 100 g of 2-acrylamido-2-methylpropanesulfonic acid, 10 g of acrylamide, 2 g of N,N-dimethylacrylamide, 1 g of itaconic acid and 4 g of isopropanol were added in sequence to obtain a reaction solution.
[0055] Step 2, stirring the reaction solution at a speed of 200 rpm, adding a 30% by mass sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 60° C.;
[0056] Step 3: add 1 g of initiator ammonium persulfate to the reaction solution, control the reaction temperature to 60° C., and react at constant temperature for 4 hours; dry and crush to obtain a fluid loss reducer.
[0057] The fluid loss additives prepared in the above Examples 1 to 4 and the comparative example were applied to cement and tested, as shown in Table 1 below, under simulated low temperature conditions of 33°C.
[0058] Table 1
[0059]
[0060] The experimental results are shown in Table 2.
[0061] Table 2 Test data table
[0062]
[0063] As shown in Table 2, compared with the comparative example, due to the addition of the additive di(triethanolamine) diisopropyl titanate and the control of the order of adding the additives, the consistency of the cement slurry increased significantly, the thickening time was reduced by more than half, the water loss was reduced by more than half, and the 24h compressive strength was increased by more than double. Compared with the comparative example 1, the cement slurry prepared by the fluid loss reducer of Examples 1, 2, 3, and 4 has strong advantages in terms of water loss, thickening time, and 24h compressive strength.
[0064] When the amount of additive added is too much, for example, 10 g of additive is added in Example 4, the consistency of the cement slurry prepared by the additive increases greatly to 34 Bc, and the fluidity decreases, which does not meet the requirements of cementing construction.
[0065] Figure 1 The thickening curve of cement slurry prepared with the fluid loss reducer prepared in Comparative Document 1 at 33°C; Figure 2 This is a thickening curve of the saline cement slurry prepared with the fluid loss reducer prepared in Example 3 at 33°C; the addition of di(triethanolamine)titanate diisopropyl not only shortens the thickening time, but also shortens the transition time, approaches right-angle thickening, and reduces the risk of air channeling in the cement ring.
[0066] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.
Claims
1. A low-temperature fluid loss agent, characterized in that: The invention is obtained by polymerizing the following components: 2-acrylamide-2-methylpropanesulfonic acid, amide monomers, carboxylic acid monomers, molecular regulators and additives, wherein the additive is di(triethanolamine)titanate diisopropyl.
2. A low-temperature fluid loss agent according to claim 1, characterized in that: The weight proportion of each component is as follows: 80-100 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, 10-15 parts by weight of amide monomer, 1-3 parts by weight of carboxylic acid monomer, 3-5 parts by weight of molecular regulator and 4-8 parts by weight of additive.
3. A low-temperature fluid loss agent according to claim 1, characterized in that: The amide monomers are one or both of acrylamide and N,N-dimethylacrylamide, and the mass ratio of acrylamide to N,N-dimethylacrylamide is 3.0-5.0:1; the carboxylic acid monomers include one or both of acrylic acid and itaconic acid, and the mass ratio of acrylic acid to itaconic acid is 1.0-2.0:1; and the molecular regulator is isopropanol.
4. The method for preparing a low-temperature fluid loss reducer according to any one of claims 1 to 3, characterized in that: The steps include: (1) adding water, 2-acrylamide-2-methylpropanesulfonic acid, an amide monomer, a carboxylic acid monomer, and a molecular weight regulator to a three-necked flask equipped with a thermometer and a stirrer to obtain a reaction solution; (2) stirring the reaction solution, adjusting the pH to 7, and heating; (3) Add initiator and continue the reaction; (4) Add additives, stir, dry and crush to obtain a fluid loss reducer.
5. The method for preparing a low-temperature fluid loss agent according to claim 4, characterized in that: In step (1), the amide monomer is one or both of acrylamide and N,N-dimethylacrylamide; the carboxylic acid monomer includes one or both of acrylic acid and itaconic acid; and the molecular regulator is isopropanol.
6. The method for preparing a low-temperature fluid loss agent according to claim 5, characterized in that: The weight of 2-acrylamide-2-methylpropanesulfonic acid is 80-100 parts, the weight of amide monomer is 10-15 parts, the weight of carboxylic acid monomer is 1-3 parts, and the weight of molecular regulator is 3-5 parts.
7. The method for preparing a low-temperature fluid loss agent according to claim 4, characterized in that: In step (2), the reaction solution is stirred at a speed of 200-300 rpm, sodium hydroxide solution is added to the reaction solution to adjust the pH to 7, and then the temperature of the reaction solution is increased to 55-60° C.; the mass concentration of the sodium hydroxide solution is 30%.
8. The method for preparing a low-temperature fluid loss agent according to claim 4, characterized in that: In step (3), the initiator is ammonium persulfate. After adding 1 part by weight of the initiator, the reaction temperature is controlled to 60° C. and the reaction is carried out at a constant temperature for 4-5 hours.
9. The method for preparing a low-temperature fluid loss agent according to claim 4, characterized in that: In step (4), the additive is diisopropyl di(triethanolamine)titanate. After adding 4-8 parts by weight of the additive, stirring is continued for 10-15 minutes and then stopped. The fluid loss additive is obtained after crushing and drying.
10. The method for preparing a low-temperature fluid loss agent according to claim 4, characterized in that: The steps include: (1) adding 80-100 parts by weight of water, 2-acrylamido-2-methylpropanesulfonic acid, 10-15 parts by weight of an amide monomer, 1-3 parts by weight of a carboxylic acid monomer, and 3-5 parts by weight of a molecular regulator to a three-necked flask equipped with a thermometer and a stirrer to obtain a reaction solution; the amide monomer is one or both of acrylamide and N,N-dimethylacrylamide; the carboxylic acid monomer includes one or both of acrylic acid and itaconic acid; and the molecular regulator is isopropanol; (2) stirring the reaction solution at a speed of 200-300 rpm, adding sodium hydroxide solution to the reaction solution to adjust the pH to 7, and then raising the temperature of the reaction solution to 55-60° C.; the mass concentration of the sodium hydroxide solution is 30%; (3) adding 1 part by weight of initiator ammonium persulfate to the reaction solution, controlling the reaction temperature to 60° C., and reacting at this constant temperature for 4-5 hours; (4) adding 4-8 parts by weight of an additive, wherein the additive is di(triethanolamine)titanate diisopropyl ester, stirring is continued for 10-15 minutes and then stopped, and drying and crushing are performed to obtain a fluid loss additive.