Novel salt-resistant drilling fluid filtrate reducer and preparation method thereof

Abstract

The invention relates to a novel salt-resistant drilling fluid filtrate reducer and a preparation method thereof, and belongs to the technical field of drilling fluid filtrate reducers, the novel salt-resistant drilling fluid filtrate reducer comprises the following raw materials by weight: 15-20 parts of N, N-dimethylacrylamide, 10-14 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6-8 parts of N-vinyl pyrrolidone, 0.9-1.2 parts of a silane coupling agent KH570, and 1-3 parts of nano clay. The adhesive is prepared from the following components in parts by weight: 5-6 parts of polyethylene glycol, 0.5-0.8 part of hexadecyl methyl ammonium bromide, 20-30 parts of hydroxyethyl cellulose, 0.5-1 part of an initiator, 0.3-0.5 part of a cross-linking agent and 60-70 parts of deionized water. The filtrate reducer disclosed by the invention has excellent salt resistance, filtrate reduction performance and good thermal stability.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling fluid fluid loss reducers and relates to a novel salt-resistant drilling fluid fluid loss reducer and a preparation method thereof. Background Art

[0002] Drilling fluid loss reducers are a type of chemical additive used to reduce the amount of drilling fluid loss. They play an important role in controlling drilling fluid loss, maintaining wellbore diameter and protecting oil layers. Loss refers to the process in which the liquid part of the drilling fluid penetrates into the formation through the pores of the wellbore rock. Excessive loss will not only lead to a reduction in the volume of the drilling fluid, but also cause problems such as wellbore instability and reduced drilling speed. Therefore, loss reducers play a vital role in the drilling fluid system.

[0003] At present, drilling fluid loss reducers are mainly divided into natural polymer and modified material loss reducers, synthetic polymer loss reducers, and inorganic / organic composite material drilling fluid loss reducers. Among them, natural polymer and modified material loss reducers include starch-based loss reducers, humic acid-based loss reducers, and cellulose-based loss reducers. Natural polymer materials have outstanding advantages in environmental protection, but natural polymer materials have obvious deficiencies in temperature and salt resistance, and it is difficult to meet the actual needs of the site. Inorganic / organic composite material drilling fluid loss reducers mainly include silica / polymer loss reducers and graphene / polymer loss reducers. Although inorganic / organic composite materials can achieve excellent temperature and salt resistance, the preparation cost is relatively high and is not suitable for industrial development. Synthetic polymer fluid loss reducers mainly include linear polymer fluid loss reducers, branched polymer fluid loss reducers and slightly cross-linked polymer fluid loss reducers. Synthetic polymer fluid loss reducers are the most widely used due to their advantages such as good thermal stability of molecular chains, strong controllability of molecular structures, a wide variety of functional monomers and a wide range of sources, and a relatively simple synthesis process.

[0004] However, the current synthetic polymer drilling fluid loss reducers have limited salt resistance. When used in salinity environments, the performance of the fluid loss reducers will be limited. Therefore, the development of synthetic polymer fluid loss reducers with stronger salt resistance is the focus of research. Summary of the invention

[0005] The present invention aims to provide a novel salt-resistant drilling fluid fluid loss reducer and a preparation method thereof. The fluid loss reducer of the present invention has excellent salt resistance, fluid loss reduction performance and good thermal stability.

[0006] The technical solution adopted by the present invention to achieve its purpose is as follows:

[0007] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 15-20 parts of N,N-dimethylacrylamide, 10-14 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6-8 parts of N-vinyl pyrrolidone, 0.9-1.2 parts of silane coupling agent KH570, 1-3 parts of nano clay, 5-6 parts of polyethylene glycol, 0.5-0.8 parts of hexadecyl methyl ammonium bromide, 20-30 parts of hydroxyethyl cellulose, 0.5-1 parts of initiator, 0.3-0.5 parts of cross-linking agent and 60-70 parts of deionized water.

[0008] Preferably, the mass ratio of N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 is 5:3.5:2:0.3.

[0009] Preferably, the polyethylene glycol is polyethylene glycol 400 and / or polyethylene glycol 600.

[0010] Preferably, the initiator is ammonium persulfate or azobisisobutyronitrile.

[0011] Preferably, the cross-linking agent is N,N'-methylenebisacrylamide or ethylene glycol dimethacrylate.

[0012] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0013] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and disperse by ultrasonication to obtain a nanoclay dispersion;

[0014] S2. Add polyethylene glycol to deionized water and stir until completely dissolved to obtain a polyethylene glycol solution;

[0015] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0016] S4. Add the nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, introduce nitrogen under nitrogen protection, add initiator and cross-linking agent, react at 60-70°C, and after the reaction is completed, cool to room temperature, dry and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0017] Preferably, the ultrasonic dispersion time is 50-60 min.

[0018] Preferably, the nitrogen is introduced for at least 30 minutes.

[0019] Preferably, during the reaction, the stirring speed is controlled at 200-300 rpm, and the reaction time is 4-6 hours.

[0020] The beneficial effects of the present invention are:

[0021] The drilling fluid filtrate reducer of the present invention has good temperature and salt resistance effects. In a freshwater-based system, with a 1% addition amount, the filtrate loss before and after aging is only 2.8-3.3 mL and 7.2-8.8 mL; in a saltwater-based system, with a 2% addition amount, the filtrate loss before and after aging is only 8.2-9.0 mL and 9.5-11.6 mL.

[0022] The present invention uses N,N-dimethylacrylamide, 2-acrylamide-2-methylpropanesulfonic acid, N-vinyl pyrrolidone, and silane coupling agent KH570 as composite monomers to synthesize a quaternary copolymer. Among them, N,N-dimethylacrylamide has high polymerization activity, a certain hydration effect, and a strong adsorption effect on clay; 2-acrylamide-2-methylpropanesulfonic acid has a strong hydration effect, which prevents viscosity particles from aggregating. Through the introduction of 2-acrylamide-2-methylpropanesulfonic acid, the polymer is endowed with strong anionic properties, which can effectively resist high-valent metal ions (such as Ca 2 +, Mg2+); N-vinyl pyrrolidone strengthens the rigid structure of the polymer and improves its resistance to temperature and salt; silane coupling agent KH570 forms a high-temperature stable silicon-oxygen bond with clay to enhance high-temperature adsorption capacity. At the same time, N,N-dimethylacrylamide and 2-acrylamido-2-methylpropanesulfonic acid work synergistically to form a dense polymer network, effectively reducing filtration loss.

[0023] The addition of nanoclay enhances the barrier properties of the polymer and further reduces filtration loss. Polyethylene glycol adjusts the hydrophilicity and molecular weight distribution of the polymer and improves the stability of the material. Hexadecyl methyl ammonium bromide is used as a dispersant to ensure that the nanoclay is evenly dispersed in the system to avoid agglomeration.

[0024] The addition of hydroxyethyl cellulose can form hydrogen bonds or coordination bonds with clay particles, thereby being adsorbed on the clay. Through hydration, the hydration film on the surface of the clay particles becomes thicker, which can produce a protective effect. In addition, multiple clay particles will be adsorbed on the same macromolecular chain at the same time to form a grid-like structure, thereby forming a thin and tough mud cake on the well wall, effectively reducing the filtration loss. At the same time, it also has good salt and high temperature resistance and good compatibility. It does not foam when added to the drilling fluid, is environmentally friendly and easy to degrade. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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 should belong to the scope of protection of the present invention. 1. Specific embodiments

[0027] Example 1

[0028] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 15 parts of N,N-dimethylacrylamide, 10.5 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6 parts of N-vinyl pyrrolidone, 0.9 parts of silane coupling agent KH570, 1 part of nano clay, 5 parts of polyethylene glycol 400, 0.5 parts of hexadecyl methyl ammonium bromide, 20 parts of hydroxyethyl cellulose, 0.5 parts of ammonium persulfate, 0.3 parts of N,N'-methylenebisacrylamide and 60 parts of deionized water.

[0029] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0030] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and ultrasonically disperse for 60 minutes to obtain a nanoclay dispersion;

[0031] S2. Add polyethylene glycol 400 to deionized water and stir until completely dissolved to obtain a polyethylene glycol 400 solution;

[0032] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0033] S4. Add nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, and introduce nitrogen for at least 30 minutes under nitrogen protection. Add ammonium persulfate and N,N'-methylenebisacrylamide, react at 65°C, control the stirring speed at 200 rpm, and react for 6 hours. After the reaction is completed, cool to room temperature, dry, and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0034] Example 2

[0035] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 20 parts of N,N-dimethylacrylamide, 14 parts of 2-acrylamido-2-methylpropanesulfonic acid, 8 parts of N-vinyl pyrrolidone, 1.2 parts of silane coupling agent KH570, 3 parts of nano clay, 6 parts of polyethylene glycol 400, 0.8 parts of hexadecyl methyl ammonium bromide, 30 parts of hydroxyethyl cellulose, 1 part of ammonium persulfate, 0.5 parts of N,N'-methylenebisacrylamide and 70 parts of deionized water.

[0036] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0037] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and ultrasonically disperse for 60 minutes to obtain a nanoclay dispersion;

[0038] S2. Add polyethylene glycol 400 to deionized water and stir until completely dissolved to obtain a polyethylene glycol 400 solution;

[0039] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0040] S4. Add nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, and introduce nitrogen for at least 30 minutes under nitrogen protection. Add ammonium persulfate and N,N'-methylenebisacrylamide, react at 70°C, control the stirring speed at 200 rpm, and react for 5 hours. After the reaction is completed, cool to room temperature, dry, and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0041] Example 3

[0042] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 17.5 parts of N,N-dimethylacrylamide, 12.25 parts of 2-acrylamido-2-methylpropanesulfonic acid, 7 parts of N-vinyl pyrrolidone, 1.05 parts of silane coupling agent KH570, 2 parts of nano clay, 5.5 parts of polyethylene glycol 400, 0.7 parts of hexadecyl methyl ammonium bromide, 25 parts of hydroxyethyl cellulose, 0.8 parts of ammonium persulfate, 0.4 parts of N,N'-methylenebisacrylamide and 65 parts of deionized water.

[0043] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0044] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and ultrasonically disperse for 60 minutes to obtain a nanoclay dispersion;

[0045] S2. Add polyethylene glycol 400 to deionized water and stir until completely dissolved to obtain a polyethylene glycol 400 solution;

[0046] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0047] S4. Add nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, and introduce nitrogen for at least 30 minutes under nitrogen protection. Add ammonium persulfate and N,N'-methylenebisacrylamide, react at 60°C, control the stirring speed at 300 rpm, and react for 6 hours. After the reaction is completed, cool to room temperature, dry, and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0048] Example 4

[0049] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 16 parts of N,N-dimethylacrylamide, 10 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6 parts of N-vinyl pyrrolidone, 0.9 parts of silane coupling agent KH570, 1 part of nano clay, 5 parts of polyethylene glycol 400, 0.5 parts of hexadecyl methyl ammonium bromide, 20 parts of hydroxyethyl cellulose, 0.5 parts of ammonium persulfate, 0.3 parts of N,N'-methylenebisacrylamide and 60 parts of deionized water.

[0050] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0051] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and ultrasonically disperse for 60 minutes to obtain a nanoclay dispersion;

[0052] S2. Add polyethylene glycol 400 to deionized water and stir until completely dissolved to obtain a polyethylene glycol 400 solution;

[0053] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0054] S4. Add nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, and introduce nitrogen for at least 30 minutes under nitrogen protection. Add ammonium persulfate and N,N'-methylenebisacrylamide, react at 65°C, control the stirring speed at 200 rpm, and react for 6 hours. After the reaction is completed, cool to room temperature, dry, and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0055] Example 5

[0056] A novel salt-resistant drilling fluid fluid loss reducer, wherein the raw materials include, by weight, 18 parts of N,N-dimethylacrylamide, 13.5 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6 parts of N-vinyl pyrrolidone, 0.9 parts of silane coupling agent KH570, 1 part of nano clay, 5 parts of polyethylene glycol 400, 0.5 parts of hexadecyl methyl ammonium bromide, 20 parts of hydroxyethyl cellulose, 0.5 parts of ammonium persulfate, 0.3 parts of N,N'-methylenebisacrylamide and 60 parts of deionized water.

[0057] A method for preparing a novel salt-resistant drilling fluid fluid loss reducer comprises the following steps:

[0058] S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and ultrasonically disperse for 60 minutes to obtain a nanoclay dispersion;

[0059] S2. Add polyethylene glycol 400 to deionized water and stir until completely dissolved to obtain a polyethylene glycol 400 solution;

[0060] S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture;

[0061] S4. Add nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, and introduce nitrogen for at least 30 minutes under nitrogen protection. Add ammonium persulfate and N,N'-methylenebisacrylamide, react at 65°C, control the stirring speed at 200 rpm, and react for 6 hours. After the reaction is completed, cool to room temperature, dry, and crush to obtain a new salt-resistant drilling fluid loss reducer.

[0062] Test Example 1

[0063] 1. Fluid loss reduction performance of freshwater-based systems

[0064] Fresh water base slurry: 1000mL distilled water + 50.0g sodium bentonite + 3g anhydrous sodium carbonate, sealed and cured at 25±3℃ for 24 hours.

[0065] The aging temperature is 230℃, and the high temperature and high pressure filtration loss is FL API / mL was measured at 3.5MPa×230℃. The results are shown in Table 1-5.

[0066] Table 1

[0067]

[0068]

[0069] Table 2

[0070]

[0071] Table 3

[0072]

[0073] Table 4

[0074]

[0075]

[0076] Table 5

[0077]

[0078] It can be seen from Tables 1-5 that the addition of the fluid loss reducer of the present invention can improve the fluid loss reduction effect of the API before and after aging. Taking all factors into consideration, an addition amount of 1.0% is the most appropriate.

[0079] 2. Comply with the fluid loss reduction performance of salt water-based systems

[0080] Salt water base slurry: 5% bentonite + 0.3% Na 2 CO 3 + fresh water + 30% NaCl + filtrate reducer, sealed and cured for 24 hours at 25±3℃.

[0081] The aging temperature is 230℃, and the high temperature and high pressure filtration loss is FL API / mL was measured under hot rolling conditions of 3.5MPa×230℃ for 16h.

[0082] See Table 6 for the results.

[0083] Table 6

[0084]

[0085]

[0086] It can be seen from Table 6 that the fluid loss reducer of the present invention can improve the fluid loss reduction effect on the salt water-based slurry, and the effect is significant when the addition amount is 3%.

Claims

1. A novel salt-resistant drilling fluid loss reducer, characterized in that: By weight, the raw materials include 15-20 parts of N,N-dimethylacrylamide, 10-14 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6-8 parts of N-vinyl pyrrolidone, 0.9-1.2 parts of silane coupling agent KH570, 1-3 parts of nano clay, 5-6 parts of polyethylene glycol, 0.5-0.8 parts of hexadecyl methyl ammonium bromide, 20-30 parts of hydroxyethyl cellulose, 0.5-1 parts of initiator, 0.3-0.5 parts of cross-linking agent, and 60-70 parts of deionized water.

2. The novel salt-resistant drilling fluid fluid loss reducer according to claim 1, characterized in that: The mass ratio of N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone, and silane coupling agent KH570 is 5:3.5:2:0.

3.

3. The novel salt-resistant drilling fluid fluid loss reducer according to claim 1, characterized in that: The polyethylene glycol is polyethylene glycol 400 and / or polyethylene glycol 600.

4. The novel salt-resistant drilling fluid fluid loss reducer according to claim 1, characterized in that: The initiator is ammonium persulfate or azobisisobutyronitrile.

5. The novel salt-resistant drilling fluid fluid loss reducer according to claim 1, characterized in that: The cross-linking agent is N,N'-methylenebisacrylamide or ethylene glycol dimethacrylate.

6. A method for preparing a novel salt-resistant drilling fluid fluid loss reducer, characterized in that: The following steps are involved: S1. Dissolve hexadecyl methyl ammonium bromide in deionized water, stir until completely dissolved, add nanoclay, and disperse by ultrasonic to obtain a nanoclay dispersion; S2. Add polyethylene glycol to deionized water and stir until completely dissolved to obtain a polyethylene glycol solution; S3. N,N-dimethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid, N-vinyl pyrrolidone and silane coupling agent KH570 were mixed in proportion and stirred to obtain a monomer mixture; S4. Add the nano-clay dispersion, polyethylene glycol solution and hydroxyethyl cellulose to the monomer mixture, stir evenly, introduce nitrogen under nitrogen protection, add initiator and cross-linking agent, react at 60-70°C, and after the reaction is completed, cool to room temperature, dry and crush to obtain a new salt-resistant drilling fluid loss reducer.

7. The method for preparing a novel salt-resistant drilling fluid fluid loss reducer according to claim 6, characterized in that: The ultrasonic dispersion time is 50-60 min.

8. The method for preparing a novel salt-resistant drilling fluid fluid loss reducer according to claim 6, characterized in that: The nitrogen gas should be introduced for at least 30 minutes.

9. The method for preparing a novel salt-resistant drilling fluid fluid loss reducer according to claim 6, characterized in that: During the reaction, the stirring speed is controlled at 200-300 rpm and the reaction time is 4-6 hours.

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