A filtrate reducer for drilling fluid based on lignin etherification method and a preparation method thereof

Abstract

The application provides a filtrate reducer for drilling fluid prepared based on a lignin etherification method, which is obtained by reacting lignin, 3-chloro-2-hydroxypropyl trimethylammonium chloride, an aldehyde compound and a sulfonating agent under alkaline conditions. Compared with the prior art, the lignin-based filtrate reducer is obtained by modifying lignin as a raw material, and the temperature resistance of the lignin-based filtrate reducer can reach 230 DEG C. Compared with conventional filtrate reducers, the lignin-based filtrate reducer has greatly improved temperature resistance, good compatibility with various water-based drilling fluids, and convenience in use. The lignin-based filtrate reducer not only improves the filtrate reduction capacity of the product, but also improves the environmental protection performance of the product. The lignin-based filtrate reducer is a new type of drilling fluid treatment agent suitable for high-temperature deep wells, promotes the progress of drilling fluid technology for deep formation exploration and development in China, and has important application value.

Description

Technical Field

[0001] This invention belongs to the field of drilling technology in petroleum engineering, and particularly relates to a filtration loss reducer for drilling fluid prepared by lignin etherification and its preparation method. Background Technology

[0002] In nature, lignin is the second largest natural polymer after cellulose. Together with cellulose and hemicellulose, lignin forms the main structure of plants. It is present in almost all vascular plants and accounts for nearly 30% of the organic carbon content in the biosphere. Every year, the world produces as much as 150 billion tons of lignin through plant photosynthesis alone. However, as a complex phenolic polymer and one of the few renewable resources among aromatic compounds, less than 5% of industrial lignin worldwide is recycled as a chemical resource annually. Over 95% of lignin is often directly discharged as waste or used as a heat source. This is not only a huge waste of resources but also causes serious pollution to the ecological environment.

[0003] my country's oil and gas resources are buried deep. For example, in the Beihai region, where deep drilling is intensive, the average well depth exceeds 5000m, and the bottom-hole temperature exceeds 200℃. In contrast, the Moshen-1 well in Karamay, Tarim Basin, at a depth of 7380m, has a bottom-hole temperature exceeding 200℃; the Yuanshen-1 well in the Sichuan Basin, at a completed depth of 8866m, has a bottom-hole temperature of 205℃; and in the deep Xujiaweizi area of ​​the northern Songliao Basin, bottom-hole temperatures range from 180 to 230℃. This presents a severe challenge to the temperature resistance of drilling fluids.

[0004] As one of the core key treatment agents for high-temperature drilling fluids, filtration loss reducers play a crucial role in wellbore stability and reservoir protection. Currently, the most widely used and effective high-temperature filtration loss reducer, sulfonated methyl phenolic resin filtration loss reducer (SMP), is made from phenol, formaldehyde, and sulfonating agents through sulfonation and polycondensation reactions. However, its temperature resistance is difficult to exceed 180℃. Yang Xiaohua et al. used epichlorohydrin and trimethylamine, while Li Yao et al. used cationic intermediates to prepare zwitterionic phenolic resin filtration reducers. Niu Zhongnian et al. introduced phenoxyacetic acid to prepare sulfonated phenoxyacetic acid-phenol-formaldehyde resin, which improved the product's salt resistance. Chen Xiaofei et al. synthesized p-aminobenzenesulfonic acid-phenol-formaldehyde resin with stable temperature resistance up to 180℃. In addition, sulfonated acetone-formaldehyde condensate and sulfomethyl melamine-formaldehyde resin have been reported in the literature, but no field application has been observed. Wang Zhonghua further improved the temperature resistance by modifying or grafting SMP, and successfully applied it in the Shunbei 16X well with a bottom temperature of 209℃. This shows that the idea of ​​synthesizing high-temperature and high-pressure filtration reducers by molecular modification is feasible, but the results cannot meet the field requirements. It is urgent to change the synthesis raw materials or synthesis methods and develop high-temperature (230℃) resistant filtration reducers. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a high-temperature resistant drilling fluid filtration reducer prepared by lignin etherification and its preparation method.

[0006] This invention provides a filtrate reducer for drilling fluids prepared by lignin etherification, which is obtained by reacting lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds and sulfonating agents under alkaline conditions.

[0007] Preferably, the lignin is coniferous lignin;

[0008] The aldehyde compounds are selected from one or more of formaldehyde, acetaldehyde, glutaraldehyde, acrolein, succinaldehyde, melamine formaldehyde, trioxymethylene, and paraformaldehyde;

[0009] The sulfonating agent is selected from one or more of sodium sulfite, sodium bisulfite, chlorosulfonic acid, sodium metabisulfite, sodium hydroxyethyl sulfonate, ammonium sulfite, and aminosulfonic acid.

[0010] Preferably, the mass ratio of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compound and sulfonating agent is (40-50):(7-9):(18.5-22.2):(20-25).

[0011] Preferably, the aldehyde compound is added in the form of an aqueous solution of the aldehyde compound; the mass concentration of the aqueous solution of the aldehyde compound is 37%; the mass ratio of the lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, the aqueous solution of the aldehyde compound and the sulfonating agent is (40-50):(7-9):(50-60):(20-25).

[0012] Preferably, the mass ratio of the lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aqueous solution of aldehyde compound and sulfonating agent is 50:(8-9):(57.57-60):(22.8-25).

[0013] Preferably, the pH value of the alkaline conditions is 10 to 11.

[0014] This invention also provides a method for preparing a filtration loss reducer for drilling fluids based on lignin etherification, comprising the following steps:

[0015] S1) Mix lignin with sodium hydroxide in water, heat and stir, then add 3-chloro-2-hydroxypropyltrimethylammonium chloride, continue stirring to react, and obtain the intermediate product;

[0016] S2) The intermediate product, aldehyde compound and sulfonating agent are mixed, and the reaction system is adjusted to alkaline conditions with sodium hydroxide. After heating and reaction, the mixture is dried to obtain a drilling fluid filtration reducer prepared based on lignin etherification method.

[0017] Preferably, in step S1), the mass ratio of lignin, sodium hydroxide and water is (40-50):(10-15):(100-130);

[0018] In step S1), the heating and stirring temperature is 75℃~85℃, and the heating and stirring time is 0.5~2h; the stirring reaction time is continued for 2~6h.

[0019] In step S2), the pH value of the alkaline conditions is 10-11; the temperature of the heating reaction is 115℃-125℃; the heating reaction time is 4-8h; and the drying temperature is 100℃-110℃.

[0020] The present invention also provides a drilling fluid, including the above-mentioned filtrate reducer for drilling fluid prepared by lignin etherification.

[0021] Preferably, the ratio of the drilling fluid filtration reducer to the drilling fluid is (2-3) g: 100 mL.

[0022] This invention provides a drilling fluid filtration reducer prepared by lignin etherification, which is obtained by reacting lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds, and a sulfonating agent under alkaline conditions. Compared with existing technologies, this invention uses lignin as a raw material to modify it into a lignin-based filtration reducer, which has a temperature resistance of up to 230℃. This not only significantly improves the temperature resistance compared to conventional filtration reducers, but also exhibits good compatibility with various water-based drilling fluids and is easy to use. It not only improves the filtration reduction capacity of the product but also enhances its environmental performance. It is a novel drilling fluid treatment agent suitable for high-temperature deep wells, contributing to the advancement of drilling fluid technology in deep formation exploration and development in my country, and has significant application value. Attached Figure Description

[0023] Figure 1 The infrared spectrum of the drilling fluid filtration reducer prepared by lignin etherification method obtained in Example 1 of this invention is shown. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a filtrate reducer for drilling fluids prepared by lignin etherification, which is obtained by reacting lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds and sulfonating agents under alkaline conditions.

[0026] The drilling fluid filtration reducer provided by this invention uses lignin as the main raw material. Lignin is a complex polymer compound found in the xylem of most terrestrial plants, and its abundance in nature is second only to cellulose. Lignin is a multi-component polymeric anionic surfactant, appearing as a light yellow to dark brown powder with a slightly aromatic odor. Its molecular weight is generally between 800 and 10,000, and it possesses strong dispersibility, binding properties, and chelating properties. It is typically derived from the cooking waste liquor of acid pulping (or sulfite pulping) and produced by spray drying. Because coniferous lignin has a hard wood structure and low cellulose content, it is easier to control the viscosity of the target product. Therefore, this invention preferably uses coniferous lignin.

[0027] This invention, using lignin as a raw material, synthesizes a filtration loss reducer with the following advantages: lignin naturally contains benzene rings and C / C bonds, exhibiting good temperature resistance; lignin possesses a three-dimensional spatial structure and is commonly used as a drilling fluid dispersant in the oil and gas field industry, effectively reducing drilling fluid viscosity and inhibiting thickening in ultra-high temperature environments; lignin is rich in benzene rings, hydroxyl groups, phenolic hydroxyl groups, and other groups, exhibiting high reactivity. Furthermore, modifying lignin to prepare a lignin-based filtration loss reducer not only reduces pulping pollutant emissions but also enables resource recycling, promotes technological progress in the oil and gas industry, and yields significant social and economic benefits.

[0028] According to the present invention, the aldehyde compound is preferably one or more of formaldehyde, acetaldehyde, glutaraldehyde, acrolein, succinaldehyde, melamine formaldehyde, trioxymethylene and paraformaldehyde, more preferably formaldehyde.

[0029] According to the present invention, the sulfonating agent is preferably one or more of sodium sulfite, sodium bisulfite, chlorosulfonic acid, sodium metabisulfite, sodium hydroxyethyl sulfonate, ammonium sulfite and aminosulfonic acid, more preferably sodium bisulfite.

[0030] According to the present invention, the preferred mass ratio of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compound, and sulfonating agent is (40-50):(7-9):(18.5-22.2):(20-25), more preferably (45-50):(7-9):(20-22.2):(22-25), and even more preferably (48-50):(7-9):(21.3-22.2):(22.8). The most preferred ratio is 50:(8-9):(21.3-22.2):(22.8-25). In some embodiments provided by the present invention, the mass ratio of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compound and sulfonating agent is specifically 50:8:21.3:22.8, 50:9:21.3:22.8, 50:8:22.2:22.8 or 50:8:21.3:25.

[0031] In a specific embodiment of the present invention, the aldehyde compound is preferably added in the form of an aqueous solution of the aldehyde compound; the mass concentration of the aqueous solution of the aldehyde compound is preferably 37%; the mass ratio of the lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, the aqueous solution of the aldehyde compound, and the sulfonating agent is preferably (40-50):(7-9):(50-60):(20-25), more preferably (45-50):(7-9):(54-60):(22-25), and even more preferably (48-50):(7-9):(54-60):(22-25), and even more preferably (48-50):(7-9):(54-60):(22-25). 0):(7~9):(57.57~60):(22.8~25), most preferably 50:(8~9):(57.57~60):(22.8~25); In some embodiments provided by the present invention, the mass ratio of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aqueous solution of aldehyde compound and sulfonating agent is specifically 50:8:57.57:22.8, 50:9:57.57:22.8, 50:8:60:22.8 or 50:8:57.57:25.

[0032] According to the present invention, the alkaline conditions are preferably provided by sodium hydroxide; the pH value of the alkaline conditions is 10 to 11.

[0033] This invention creatively uses lignin and 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA) as raw materials for reducing filtration loss, and its temperature resistance is significantly better than that of the traditional filtration loss reducing agent SMP.

[0034] Lignin (Latin, English, German: Lignin) is a three-dimensional polymer network structure composed of phenylpropane. Its molecular structure contains active functional groups such as hydroxyl, carboxyl, and carbonyl groups, allowing it to undergo chemical reactions such as alkylation, esterification, and acylation. Therefore, the active functional groups of lignin can be controlled through grafting modification and structural modification to adjust its properties. Currently, anionization, especially sulfonation modification, is a well-established process for lignin modification. However, there is less literature on cationic modification, and even fewer products are used in practice.

[0035] 3-Chloro-2-hydroxypropyltrimethylammonium chloride (CTA) is a quaternary ammonium cationic etherifying agent with active groups. Etherification modification using CTA can lead to the synthesis of a drilling fluid filtration reducer prepared by lignin etherification, which can form a network three-dimensional structure, ensuring the product's temperature resistance while improving its biodegradability.

[0036] The principle of etherification modification using CTA can be expressed by the following formula:

[0037] (1) Under the action of sodium hydroxide, the ether bond of lignin breaks and the lignin macromolecules gradually degrade, existing in the form of sodium lignin salt, which is a hydrophilic colloid.

[0038] (2) CTA undergoes a cyclization reaction in an alkaline environment to generate glycerol trimethylammonium chloride, as shown in Formula 1.

[0039] (3) Glyceryl trimethylammonium chloride undergoes an affinity substitution reaction with the sodium lignin salt in (1) to obtain etherified lignin, as shown in Formula 2.

[0040]

[0041]

[0042] This invention modifies lignin to obtain a lignin-based fluid loss reducer, which has a temperature resistance of up to 230℃. This not only significantly improves the temperature resistance compared to conventional fluid loss reducers, but also has good compatibility with various water-based drilling fluids and is easy to use. It not only improves the fluid loss reduction capacity of the product, but also enhances its environmental performance. It is a new type of drilling fluid treatment agent suitable for high-temperature deep wells, which will help promote the advancement of drilling fluid technology for deep formation exploration and development in my country and has important application value.

[0043] The present invention also provides a method for preparing a filtrate reducer for drilling fluid based on lignin etherification, comprising the following steps: S1) mixing lignin and sodium hydroxide in water, heating and stirring, then adding 3-chloro-2-hydroxypropyltrimethylammonium chloride, and continuing to stir the reaction to obtain an intermediate product; S2) mixing the intermediate product, an aldehyde compound and a sulfonating agent, and adjusting the reaction system to alkaline conditions using sodium hydroxide, heating the reaction, and drying to obtain a filtrate reducer for drilling fluid based on lignin etherification.

[0044] In this invention, there are no special restrictions on the source of any raw materials; commercially available materials are acceptable. The types and proportions of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds, and sulfonating agents are the same as described above and will not be repeated here.

[0045] Lignin and sodium hydroxide are mixed in water, heated and stirred, and then 3-chloro-2-hydroxypropyltrimethylammonium chloride is added. The reaction is continued with stirring to obtain an intermediate product. The preferred mass ratio of lignin, sodium hydroxide and water is (40-50):(10-15):(100-130), more preferably (45-50):(11-14):(100-130), even more preferably (48-50):(12-13):(100-130), and most preferably 50:12. 26: (100~130); The heating and stirring temperature is preferably 75℃~85℃, more preferably 78℃~82℃; The heating and stirring time is preferably 0.5~2h, more preferably 0.8~1.5h, even more preferably 0.8~1.2h, and most preferably 1h; The stirring reaction time is preferably 2~6h, more preferably 3~5h, even more preferably 3.5~4.5h, and most preferably 4h; After the stirring reaction is completed, it is preferable to cool to room temperature to obtain the intermediate product.

[0046] The intermediate product, aldehyde compound, and sulfonating agent are mixed, and the reaction system is adjusted to alkaline conditions using sodium hydroxide. After heating and reaction, the mixture is dried to obtain a drilling fluid filtration reducer prepared by lignin etherification. The pH value of the alkaline conditions is preferably 10-11; too high or too low a pH will prevent the acquisition of the target product. The heating reaction is preferably carried out in a micro-pressure reactor. The heating reaction temperature is preferably 115℃-125℃, more preferably 118℃-122℃. The heating reaction time is preferably 4-8h, more preferably 5-7h, even more preferably 5.5-6.5h, and most preferably 6h. The drying temperature is preferably 100℃-110℃, more preferably 103℃-107℃. By drying to constant weight, the drilling fluid filtration reducer prepared by lignin etherification can be obtained.

[0047] The present invention also provides a drilling fluid, including the above-mentioned filtrate reducer for drilling fluid prepared by lignin etherification.

[0048] According to the present invention, the ratio of the drilling fluid filtration reducer to the drilling fluid is preferably (2-4) g: 100 mL, more preferably (2-3) g: 100 mL. Within this range, the drilling fluid system exhibits good filtration reduction performance. Considering both the overall effect and cost, the present invention recommends adding 2% (g / mL) when preparing drilling fluid, 2% (g / mL) for maintenance below 180°C, and 3% (g / mL) for maintenance above 180°C.

[0049] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a drilling fluid filtration reducer prepared by lignin etherification and its preparation method.

[0050] All reagents used in the following examples are commercially available; the lignin used in the examples and comparative examples was purchased from Shanghai Changfa New Materials Co., Ltd.; 3-chloro-2-hydroxypropyltrimethylammonium chloride, formaldehyde, anhydrous sodium bisulfite, and sodium hydroxide are all industrial products that meet the relevant national and industry standards; and the water used is industrial water.

[0051] Example 1

[0052] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 8 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 22.80 g of sodium bisulfite and 57.57 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 10-11 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0053] The product obtained in Example 1 was analyzed using infrared spectroscopy (using an FT-IR430 infrared spectrometer with KBr pellet method), and its infrared spectrum is shown below. Figure 1 As shown. By Figure 1 It can be seen that 1638 cm⁻¹ in the infrared spectrum -1 This is the characteristic absorption peak of the benzene ring in lignin, at 1478 cm⁻¹. -1 The characteristic absorption peak of quaternary ammonium ions is 1454 cm⁻¹. -1 The absorption peak at this point is caused by the bending vibration of the methyl and methylene groups on the lignin benzene ring, indicating that the product molecule contains quaternary ammonium ions.

[0054] Example 2

[0055] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 9 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 22.80 g of sodium bisulfite and 57.57 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 10-11 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0056] Example 3

[0057] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 8 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 22.80 g of sodium bisulfite and 60 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 10-11 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0058] Example 4

[0059] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 8 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 25 g of sodium bisulfite and 57.57 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 10-11 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0060] Example 5

[0061] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 6 g (2% by volume) of the drilling fluid filtration reducer prepared in Example 1 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of the high-temperature high-pressure (HTHP) filtration test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 18 mL.

[0062] Example 6

[0063] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared in Example 1 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of the high-temperature high-pressure (HTHP) filtration loss test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 16 mL.

[0064] Example 7

[0065] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared in Example 2 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014), specifically the high-temperature high-pressure (HTHP) filtration loss test procedure. The HTHP filtration loss was 25 mL.

[0066] Example 8

[0067] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared in Example 3 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014), specifically the high-temperature high-pressure (HTHP) filtration loss test procedure. The HTHP filtration loss was 24 mL.

[0068] Example 9

[0069] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared in Example 4 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of the high-temperature high-pressure (HTHP) filtration loss test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 25 mL.

[0070] Example 10

[0071] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 12 g (4% by volume) of the drilling fluid filtration reducer prepared in Example 1 based on the lignin etherification method was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014), with a high-temperature high-pressure (HTHP) filtration loss test result of 20 mL.

[0072] Comparative Example 1

[0073] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 8 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 22.80 g of sodium bisulfite and 60 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 11.5–12 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0074] Comparative Example 2

[0075] 100 mL of water, 12.26 g of sodium hydroxide, and 50 g of lignin were added to a three-necked flask equipped with an electric stirrer, thermometer, constant pressure dropping funnel, and reflux condenser. The mixture was stirred at 80℃±2℃ for 1 h, then 8 g of etherification reagent CTA was added, and the reaction was continued with stirring for 4 h. The mixture was then cooled to room temperature. 22.80 g of sodium bisulfite and 60 g of 37% formaldehyde solution were added to the product, and the pH was adjusted to 7 using sodium hydroxide. The mixture was then placed in a micro-pressure reactor and reacted at 120℃±2℃ for 6 h. The liquid product was dried at 105℃±2℃ to constant weight to obtain the target product.

[0076] Comparative Example 3

[0077] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared based on the lignin etherification method in Comparative Example 1 was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of the high-temperature high-pressure (HTHP) filtration loss test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 98 mL.

[0078] Comparative Example 4

[0079] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared by the lignin etherification method in Comparative Example 2 was added. The mixture was then aged in a 230℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of the high-temperature high-pressure (HTHP) filtration loss test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 136 mL.

[0080] Comparative Example 5

[0081] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 9 g (3% by volume) of the drilling fluid filtration reducer prepared in Example 1 based on the lignin etherification method was added. The mixture was then aged in a 240℃ high-temperature roller furnace for 16 h. The test was conducted according to section 7.3 of "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014), specifically the high-temperature and high-pressure (HTHP) filtration loss test procedure. The HTHP filtration loss was 42 mL.

[0082] Comparative Example 6

[0083] The test slurry was prepared according to section 4.3.6.1 of the industry standard "Sulfomethylphenolic resin SMP for Drilling Fluids" (SY / T 5094-2017). 300.0 mL of the test slurry was weighed into a 400 mL high-speed stirring cup, and then 12 g of SMP (produced by Shandong Deshunyuan Petroleum Technology Co., Ltd.) (4% by mass / volume) was added. The mixture was then aged in a 240℃ high-temperature roller furnace for 16 hours. The test was conducted according to section 7.3 of the high-temperature and high-pressure (HTHP) filtration loss test procedure in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry Part 1: Water-based Drilling Fluids" (GB / T16783.1-2014). The HTHP filtration loss was 140 mL.

[0084] The measured high-temperature and high-pressure filtration loss data of Examples 5-9 and Comparative Examples 3-7 are summarized in the table.

[0085] Table 2. Experimental results of Examples 5-9 and Comparative Examples 3-7

[0086]

[0087]

[0088] As shown in Examples 5 to 9, the products synthesized using the synthesis processes of Examples 1 to 4 have a temperature resistance of up to 230℃. Using 2% and 3% high-temperature, high-pressure additives, the filtration loss is 18 mL and 16 mL respectively, demonstrating good filtration loss reduction.

[0089] Comparative Examples 3 and 4 show that pH value has a significant impact on the performance of the target product during the synthesis process, and the pH value is strictly controlled between 10 and 11 during the synthesis process.

[0090] A comparison of Examples 10, 5, and 6 shows that under optimized ratio conditions, the increase in product usage is not linearly related to the increase in filtration loss. When the usage is increased by 4%, the filtration loss is 20 mL, which is actually an increase. Therefore, the optimal usage is 2% to 3% in field applications, which can balance performance and economy.

[0091] As shown in Comparative Example 5, the product’s high-temperature and high-pressure filtration loss increases significantly with increasing test temperature. This is likely due to the breakage of molecular chains, which causes the product to lose its filtration loss reduction function. This also indicates that the product is resistant to temperatures up to 230℃.

[0092] As shown in Comparative Example 6, the temperature resistance of traditional sulfomethylphenol resin SMP cannot reach 230℃, indicating that the filtration loss reducer provided by the present invention has good temperature resistance.

[0093] According to the industry standard SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemical Agents", the biodegradability of the drilling fluid filtration reducer prepared by the lignin etherification method in Example 1 of this invention was tested. The biodegradability BOD / COD ratio was measured. Cr With a value of 10.40 (the standard is greater than 5 for biodegradability), it has good environmental compatibility and is a high-performance, environmentally friendly, high-temperature filtration reduction agent.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A filtration loss reducer for drilling fluids prepared by lignin etherification, characterized in that, It is obtained by reacting lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds and sulfonating agents under alkaline conditions.

2. The drilling fluid filtration reducer according to claim 1, characterized in that, The lignin is coniferous lignin; The aldehyde compounds are selected from one or more of formaldehyde, acetaldehyde, glutaraldehyde, acrolein, succinaldehyde, melamine formaldehyde, trioxymethylene, and paraformaldehyde; The sulfonating agent is selected from one or more of sodium sulfite, sodium bisulfite, chlorosulfonic acid, sodium metabisulfite, sodium hydroxyethyl sulfonate, ammonium sulfite, and aminosulfonic acid.

3. The drilling fluid filtration reducer according to claim 1, characterized in that, The mass ratio of lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aldehyde compounds and sulfonating agent is (40-50):(7-9):(18.5-22.2):(20-25).

4. The drilling fluid filtration reducer according to claim 1, characterized in that, The aldehyde compound is added in the form of an aqueous solution of the aldehyde compound; the mass concentration of the aqueous solution of the aldehyde compound is 37%; the mass ratio of the lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aqueous solution of the aldehyde compound and the sulfonating agent is (40-50):(7-9):(50-60):(20-25).

5. The drilling fluid filtration reducer according to claim 4, characterized in that, The mass ratio of the lignin, 3-chloro-2-hydroxypropyltrimethylammonium chloride, aqueous solution of aldehyde compound and sulfonating agent is 50:(8-9):(57.57-60):(22.8-25).

6. The drilling fluid filtration reducer according to claim 1, characterized in that, The pH value of the alkaline conditions is 10 to 11.

7. A method for preparing a filtrate reducer for drilling fluids based on lignin etherification, characterized in that, Includes the following steps: S1) Mix lignin with sodium hydroxide in water, heat and stir, then add 3-chloro-2-hydroxypropyltrimethylammonium chloride, continue stirring to react, and obtain the intermediate product; S2) The intermediate product, aldehyde compound and sulfonating agent are mixed, and the reaction system is adjusted to alkaline conditions with sodium hydroxide. After heating and reaction, the mixture is dried to obtain a drilling fluid filtration reducer prepared based on lignin etherification method.

8. The preparation method according to claim 7, characterized in that, In step S1), the mass ratio of lignin, sodium hydroxide and water is (40-50):(10-15):(100-130). In step S1), the heating and stirring temperature is 75℃~85℃, and the heating and stirring time is 0.5~2h; the stirring reaction time is continued for 2~6h. In step S2), the pH value of the alkaline conditions is 10-11; the temperature of the heating reaction is 115℃-125℃; the heating reaction time is 4-8h; and the drying temperature is 100℃-110℃.

9. A drilling fluid, characterized in that, Includes the drilling fluid filtration reducer prepared by the lignin etherification method according to any one of claims 1 to 6, or the drilling fluid filtration reducer prepared by the preparation method according to claim 7 or 8.

10. The drilling fluid according to claim 9, characterized in that, The ratio of the filtration loss reducer to the drilling fluid is (2-3) g: 100 mL.

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