High-temperature stabilizer for sulfonated drilling fluid, preparation method and application thereof

Abstract

This invention provides a high-temperature stabilizer for sulfonated drilling fluids, its preparation method, and its application. The stabilizer comprises low-valent sulfur oxyacid salts and hydroxyalkyl sulfonates. The high-temperature stabilizer for sulfonated drilling fluids is prepared according to the following steps: mixing low-valent sulfur oxyacid salts and carbonyl compounds in water, adding an inorganic alkali to adjust the pH to 8-10, and reacting under high-temperature sealed conditions to obtain the high-temperature stabilizer for sulfonated drilling fluids. The low-valent sulfur oxyacid salts include divalent sulfur oxyacid salts and / or tetravalent sulfur oxyacid salts; the carbonyl compounds include aldehydes and / or ketones; the molar ratio of sulfur in the low-valent sulfur oxyacid salts to the carbonyl groups in the carbonyl compounds is (1.2-2.0):1. The high-temperature stabilizer in this invention is a composition formed by low-valent sulfates and hydroxyalkyl sulfonates. This composition can simultaneously eliminate the active hydroxymethyl and hydrogen atoms on the phenolic ring structure of the sulfonated material and can also inhibit the desulfonation reaction of the treatment agent.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemical technology, and particularly relates to a high-temperature stabilizer for sulfonated drilling fluid, its preparation method and application. Background Technology

[0002] As oil and gas exploration and development moves towards deeper and ultra-deeper formations, the demand for drilling fluid systems resistant to ultra-high temperatures (180℃~260℃) is becoming increasingly strong. "Trisulfonated" / "polysulfonated" drilling fluids are currently the most important construction system for deep and ultra-deep wells. The core treatment agents are sulfonated methyl phenolic resin (SMP) and sulfonated lignite (SMC). Due to the presence of certain active groups (hydroxymethyl) in their molecular structure, they can undergo a "cross-linking reaction" with other treatment agents at high temperatures. This "moderate cross-linking" can partially or completely offset the failure caused by the degradation of treatment agents at high temperatures, improving the performance of the drilling fluid and basically meeting the operational requirements of resisting temperatures up to 180℃ and salt saturation.

[0003] However, as bottom-hole temperatures rise, conventional systems are prone to "improper cross-linking reactions," including "over-cross-linking" and "under-cross-linking." "Over-cross-linking" leads to the formation of complex, insoluble network structures, resulting in decreased drilling fluid fluidity and increased water loss, manifesting as high-temperature thickening, and even high-temperature gelation and solidification. This chemically induced thickening cannot be controlled by adding viscosity reducers, posing a significant safety hazard. "Under-cross-linking," on the other hand, causes substantial degradation of the treatment agent, leading to decreased shear strength and increased filtration loss in the drilling fluid, exhibiting high-temperature dethickening. This necessitates shorter maintenance cycles and the replenishment of large amounts of treatment agent, increasing costs. Therefore, high-temperature cross-linking of drilling fluids is both a solution to the problems of short maintenance cycles and large treatment agent usage caused by high-temperature degradation and a source of difficulty in controlling rheology and filtration loss at high temperatures.

[0004] The development of traditional high-temperature stabilizers is based on chromium-containing systems (such as chromium sulfonate PSC-2 and iron-chromium lignin sulfonate SPC as stabilizing additives for drilling fluids). However, due to environmental protection requirements, drilling fluids are now being de-chromiumized, and the high-temperature stability of the de-chromium-containing drilling fluids will face even more severe challenges. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature stabilizer for sulfonated drilling fluids, its preparation method, and its application. The high-temperature stabilizer for sulfonated drilling fluids in this invention can solve the problems of poor ultra-high temperature rheological properties, large filtration loss, and short maintenance cycle in chromium-free drilling fluid systems.

[0006] This invention provides a high-temperature stabilizer for sulfonated drilling fluids, comprising low-valent sulfur oxyacid salts and hydroxyalkyl sulfonates, wherein the sulfonated drilling fluid high-temperature stabilizer is prepared according to the following steps:

[0007] Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions to obtain a sulfonated drilling fluid high-temperature stabilizer.

[0008] The oxyacid salts of low-valent sulfur include oxyacid salts of divalent sulfur and / or oxyacid salts of tetravalent sulfur;

[0009] The carbonyl compounds include aldehydes and / or ketones;

[0010] The molar ratio of sulfur in the oxyacid salt of the low-valent sulfur to the carbonyl group in the carbonyl compound is (1.2 to 2.0): 1.

[0011] Preferably, the low-valent sulfur oxyacid salt includes one or more of sodium metabisulfite, sodium sulfite, sodium bisulfite, potassium metabisulfite, potassium sulfite, potassium bisulfite, sodium thiosulfate, and potassium thiosulfate.

[0012] Preferably, the carbonyl compound includes one or more of formaldehyde, paraformaldehyde, furfural, acetone, and butanone.

[0013] Preferably, the reaction temperature is 60–100°C, and the reaction time is 2–6 hours.

[0014] Preferably, an aqueous solution with a mass concentration of 20% to 60% is prepared by dissolving the oxyacid salt of low-valent sulfur in water, and then a carbonyl compound is added.

[0015] Preferably, the reaction is carried out under stirring conditions at a speed of 100–400 rpm.

[0016] This invention provides a method for preparing a high-temperature stabilizer for sulfonated drilling fluid as described above, comprising the following steps:

[0017] Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions. After the reaction is completed, the reaction product is dried and pulverized after cooling, depressurization and discharge to obtain a sulfonated drilling fluid high-temperature stabilizer.

[0018] This invention provides the application of the high-temperature stabilizer for sulfonated drilling fluids as described above in chromium-free sulfonated water-based drilling fluids.

[0019] Preferably, the mass of the high-temperature stabilizer added to the sulfonated drilling fluid is 1% to 40% of the total mass of the sulfonated materials used in the drilling fluid.

[0020] Preferably, the sulfonated materials in the chromium-free sulfonated water-based drilling fluid include sulfonated methyl phenolic resin and sulfonated lignite.

[0021] This invention provides a high-temperature stabilizer for sulfonated drilling fluids, comprising oxyacid salts of low-valent sulfur and hydroxyalkyl sulfonates. The high-temperature stabilizer for sulfonated drilling fluids is prepared according to the following steps: mixing oxyacid salts of low-valent sulfur and carbonyl compounds in water, adding an inorganic base to adjust the pH to 8-10, and reacting under high-temperature sealed conditions to obtain the high-temperature stabilizer for sulfonated drilling fluids; the oxyacid salts of low-valent sulfur include oxyacid salts of divalent sulfur and / or oxyacid salts of tetravalent sulfur; the carbonyl compounds include aldehydes and / or ketones; the molar ratio of sulfur in the oxyacid salts of low-valent sulfur to carbonyl groups in the carbonyl compounds is (1.2-2.0):1. The high-temperature stabilizer of this invention is a composition formed by low-valent sulfates and hydroxyalkyl sulfonates, prepared by a nucleophilic addition reaction of low-valent sulfur atom oxyacid salts with carbonyl groups. Among them, low-valent sulfur atom oxyacid salts, such as sulfites (SO32-SO4 ... 2- It can undergo a nucleophilic substitution reaction with the hydroxymethyl (-CH2OH) group on the SMP structure, converting the hydroxymethyl group into a sulfonyl (-CH2SO) group. 3- ), hydroxyalkyl sulfonate (HO-R-SO) 3- The active hydrogen atom (-H) of the SMP structure undergoes an electrophilic substitution reaction with the carbon atom (C) attached to the active hydrogen atom (-H), converting the active hydrogen atom into a sulfonyl group (-R-SO). 3- The composition can simultaneously eliminate the active hydroxymethyl and hydrogen atoms on the phenolic ring structure of the sulfonated material, and since the composition is a desulfonation product of the sulfonating agent, it can also inhibit the desulfonation reaction of the agent.

[0022] Compared with the prior art, the present invention has the following superior effects:

[0023] 1. The sulfonated drilling fluid high-temperature stabilizer additive used in this invention requires a small amount and has a low cost;

[0024] 2. The method of this invention is simple to operate, convenient to use, and easy to control;

[0025] 3. The method of the present invention can significantly improve the high-temperature stability of drilling fluid and reduce the viscosity and filtration loss of drilling fluid. Without changing other components, it can increase the temperature of saturated brine and near-saturated brine sulfonated drilling fluid by more than 30°C, effectively expanding the application range of sulfonated drilling fluid and enabling it to be used in high-temperature formations of 180°C to 200°C.

[0026] 4. The method used in this invention is universal and can be used to improve the performance of all sulfonated drilling fluid systems, enhance their temperature and salt resistance, and improve their high-temperature stability. It is especially suitable for chromium-free sulfonated drilling fluid systems and can compensate for the decrease in stability of sulfonated drilling fluids caused by the lack of chromium. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 The above is the 1H NMR spectrum of the high-temperature stabilizer prepared in Example 3 of this invention;

[0029] Figure 2 The image shows the carbon NMR spectrum of the high-temperature stabilizer prepared in Example 3 of this invention.

[0030] Figure 3 The FT-IR spectrum of the high-temperature stabilizer prepared in Example 3 of this invention is shown below.

[0031] Figure 4 The X-ray photoelectron spectrum (full scan spectrum) of the high-temperature stabilizer prepared in Example 3 of this invention;

[0032] Figure 5 The X-ray photoelectron spectrum (fine sulfur atom spectrum) of the high-temperature stabilizer prepared in Example 3 of this invention. Detailed Implementation

[0033] This invention provides a high-temperature stabilizer for sulfonated drilling fluids, comprising low-valent sulfur oxyacid salts and hydroxyalkyl sulfonates, wherein the sulfonated drilling fluid high-temperature stabilizer is prepared according to the following steps:

[0034] Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions to obtain a sulfonated drilling fluid high-temperature stabilizer.

[0035] The oxyacid salts of low-valent sulfur include oxyacid salts of divalent sulfur and / or oxyacid salts of tetravalent sulfur;

[0036] The carbonyl compounds include aldehydes and / or ketones;

[0037] The molar ratio of sulfur in the oxyacid salt of the low-valent sulfur to the carbonyl group in the carbonyl compound is (1.2 to 2.0): 1.

[0038] The present invention is based on the active groups of sulfonated drilling fluid crosslinking being hydroxymethyl (-CH2OH) and hydrogen atoms (-H) on the phenol ring. A combination of low-valent sulfur atom oxyacid salts and hydroxyalkyl sulfonates is used to react and transform them into sulfonyl (-CR1R2SO) under high-temperature conditions at the bottom of the well. 3-This composition regulates the degree of cross-linking reaction caused by active groups. It can simultaneously eliminate active hydroxymethyl and hydrogen atoms on the phenolic ring structure of sulfonated materials. Furthermore, since the composition is a desulfonation product of the sulfonating agent, it can also inhibit the desulfonation reaction of the agent. This meets the requirements for rheological properties and filtration loss control in high-temperature and ultra-high-temperature drilling fluid systems.

[0039] In this invention, the high-temperature stabilizer for sulfonated drilling fluid is prepared by reacting an excess of low-valent sulfur oxyacid salts with a carbonyl compound under specific conditions. The specific steps are as follows:

[0040] Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high-temperature sealed conditions to obtain a sulfonated high-temperature stabilizer for drilling fluids. The reaction principle is shown in Formula I:

[0041]

[0042] The present invention preferably involves dissolving a low-valent sulfur oxyacid salt in water to prepare an aqueous solution with a mass concentration of 20% to 60%, then adding a carbonyl compound, adjusting the pH value to 8 to 10 with an inorganic base, adding the solution to a reaction vessel, and reacting under sealed conditions to obtain a sulfonated drilling fluid high-temperature stabilizer.

[0043] In this invention, the low-valent sulfur oxyacid salt preferably includes divalent sulfur oxyacid salts and / or tetravalent sulfur oxyacid salts, more preferably one or more of sodium metabisulfite, sodium sulfite, sodium bisulfite, potassium metabisulfite, potassium sulfite, potassium bisulfite, sodium thiosulfate, and potassium thiosulfate; the carbonyl compound preferably includes aldehydes and / or ketones, more preferably one or more of formaldehyde, paraformaldehyde, paraformaldehyde, furfural, acetone, and butanone; the molar ratio of sulfur in the low-valent sulfur oxyacid salt to carbonyl group in the carbonyl compound is preferably (1.2-2.0):1, more preferably (1.5-1.8):1, such as 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, preferably a range of values ​​with any of the above values ​​as the upper or lower limit.

[0044] In this invention, the mass concentration of the aqueous solution of the low-valent sulfur oxyacid salt is preferably 20% to 60%, more preferably 30% to 50%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, and 60%, preferably within the range of any of the above values ​​as the upper or lower limit. When the concentration is too high, the reaction rate is too fast, leading to problems such as material spraying and side reactions due to heat accumulation. Furthermore, considering the solubility of the product, if the concentration is too high, the raw materials and products cannot be co-soluble, causing difficulties in stirring and discharging.

[0045] In this invention, the inorganic base is preferably sodium hydroxide and / or potassium hydroxide. There are no special restrictions on the amount of inorganic base used, as long as it can adjust the pH of the system to between 8 and 10. When the system pH is >10, formaldehyde readily undergoes the Cannizzaro reaction (2HCHO + NaOH → CH3OH + HCOONa), with a lower limit of 8, which is considered in relation to the reaction yield.

[0046] In this invention, the reaction temperature is preferably 60–100°C, more preferably 70–90°C, such as 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, preferably within a range where any of the above values ​​is the upper or lower limit; the reaction time is preferably 2–6 hours, more preferably 3–5 hours. The reaction is preferably carried out under high-temperature, sealed conditions, which on the one hand prevents formaldehyde volatilization and also prevents the solvent water from easily escaping in vapor form due to the exothermic reaction, and on the other hand prevents the oxidation of low-valent sulfates, formaldehyde, etc.

[0047] In this invention, the reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 100-400 rpm, more preferably 200-300 rpm.

[0048] This invention also provides a method for preparing the high-temperature stabilizer for sulfonated drilling fluids described above, comprising the following steps:

[0049] Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions. After the reaction is completed, the reaction product is dried and pulverized after cooling, depressurization and discharge to obtain a sulfonated drilling fluid high-temperature stabilizer.

[0050] In this invention, the process of "mixing low-valent sulfur oxyacid salts and carbonyl compounds in water, adding an inorganic base to adjust the pH to 8-10, and carrying out the reaction under high temperature and sealed conditions" involves the same types and proportions of raw materials and reaction process parameters as described above for the reaction of low-valent sulfur oxyacid salts and carbonyl compounds, and will not be repeated here.

[0051] In this invention, the cooling, depressurization, and discharge are all conventional operations in the art. The drying is preferably spray drying, the inlet temperature of the spray drying is preferably 250-350°C, more preferably 300-320°C, and the outlet temperature of the spray drying is preferably 100-130°C, more preferably 110-120°C.

[0052] The present invention also provides an application of the high-temperature stabilizer for sulfonated drilling fluid described above in chromium-free sulfonated water-based drilling fluid. The high-temperature stabilizer for sulfonated drilling fluid in the present invention is suitable for sulfonated water-based drilling fluid with sulfonylmethylphenol resin (SMP) as the core, and can improve the high-temperature stability of drilling fluid even under conditions without chromium-containing stabilizers.

[0053] In this invention, the addition mass of the high-temperature stabilizer for the sulfonated drilling fluid is preferably 1% to 40% of the total mass of the sulfonated materials used in the drilling fluid, more preferably 5% to 30%, such as 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, preferably within the range of any of the above values ​​as the upper or lower limit.

[0054] This invention provides a high-temperature stabilizer for sulfonated drilling fluids, its preparation method, and its application. A composition of low-valent sulfur atom oxyacid salts and hydroxyalkyl sulfonates is prepared through an addition reaction of low-valent sulfur atom oxyacid salts with carbonyl compounds (aldehydes / ketones). This composition is then added to sulfonated drilling fluids containing sulfonated methylphenol resin as a high-temperature stabilizer. The low-valent sulfur atom oxyacid salts and hydroxyalkyl sulfonates can inhibit the shedding of sulfonated materials under high temperature and high pressure conditions of sulfonate groups. Furthermore, they can react with materials such as sulfonated lignite and sulfonated phenol resin, which have high-temperature active sites, to regulate the cross-linking reaction between sulfonated materials, maintain good rheological properties and wall-building properties in the drilling fluid system, and significantly improve the high-temperature stability of the sulfonated drilling fluid.

[0055] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, describes a high-temperature stabilizer for sulfonated drilling fluid provided by the present invention, its preparation method, and its application, but this should not be construed as limiting the scope of protection of the present invention.

[0056] Unless otherwise specified, all percentages in the embodiments are by weight, and all chemicals used are commonly used in drilling sites.

[0057] SMP-I is a sulfomethylphenolic resin, produced by Henan Lankao Desheng.

[0058] SMC is sulfonated lignite, produced by Desheng in Lankao, Henan.

[0059] Example 1

[0060] Potassium metabisulfite (133.38 g, 0.60 mol) was dissolved in 588.5 g of water. After the solution was evenly dissolved, acetaldehyde (22 g, 0.50 mol) was added. The pH value was adjusted to 8-10 with an inorganic base and added to a reaction vessel. Under sealed conditions at 60°C, the mixture was stirred at 100 rpm for 2 hours. After cooling, depressurization, and discharge, the product was dried and pulverized to prepare a powdered product, sulfonated drilling fluid high-temperature stabilizer 1, whose main components are sodium metabisulfite, sodium sulfite, and sodium 1-hydroxyethanesulfonate.

[0061] Example 2

[0062] Sodium sulfite (75.6 g, 0.60 mol) and potassium bisulfite (96.16 g, 0.80 mol) were dissolved in 536.1 g of water. After the solution was evenly dissolved, acetone (58 g, 1.00 mol) was added. The pH value was adjusted to 8-10 with an inorganic base and added to a reaction vessel. Under sealed conditions at 70°C, the mixture was stirred at 200 rpm for 3 hours. After cooling, depressurization, and discharge, the product was dried and pulverized to prepare a powdered product, sulfonated drilling fluid high-temperature stabilizer 2, whose main components are sodium and potassium salts of sulfurous acid and sodium and potassium salts of 2-hydroxy-2-propanesulfonic acid.

[0063] Example 3

[0064] Sodium metabisulfite (152.08 g, 0.80 mol) and potassium metabisulfite (177.84 g, 0.80 mol) were dissolved in 514.4 g of water. After the solution was evenly dissolved, formaldehyde (15 g, 0.50 mol) and trioxymethylene (15 g, 0.50 mol) were added. The pH value was adjusted to 8-10 with an inorganic alkali and added to a reaction vessel. Under sealed conditions at 80°C, the mixture was stirred at 300 rpm for 4 hours. After cooling, depressurization, and discharge, the product was dried and pulverized to prepare a powdered product, sulfonated drilling fluid high-temperature stabilizer 3, whose main components are sodium and potassium salts of metabisulfite and sulfurous acid and sodium hydroxymethylsulfonate.

[0065] The high-temperature stabilizer from Example 3 was dissolved in deuterium water (D2O) solvent, and then... 1 H NMR and 13 C NMR characterizes the chemical structure of organic compounds, such as Figures 1-2 As shown, where Figure 1 shown 1 In H NMR, the chemical shift at 4.79 ppm is the solvent peak, and only a single peak with a chemical shift of 4.42 ppm exists, which is attributed to hydroxyalkyl sulfonate (methylene-CH2- in sodium hydroxymethyl sulfonate). Figure 2 shown 13 In C NMR, only a single peak with a chemical shift of 74.16 ppm was observed, which was attributed to hydroxyalkyl sulfonate (methylene-CH2- in sodium hydroxymethyl sulfonate), indicating that the prepared high-temperature stabilizer composition for drilling fluid contained hydroxyalkyl sulfonate (sodium hydroxymethyl sulfonate).

[0066] The structures of the high-temperature stabilizer composition for drilling fluid in Example 3 and commercially available sodium hydroxymethylsulfonate were compared using FT-IR spectroscopy. Figure 3 As shown. The high-temperature stabilizer is at 3524.1 cm⁻¹. -1 3437.9cm -1 3278.7cm -1Three distinct peaks appeared at 2975.4 cm⁻¹, attributed to the stretching vibration of hydroxyl groups in the water of crystallization. Sodium hydroxymethanesulfonate showed a broad peak, attributed to hydroxyl association. The difference may be due to the presence of sodium metabisulfite in the high-temperature stabilizer, which altered the hydrogen bond structure between sodium hydroxymethanesulfonate and water molecules. -1 The peak at 2882.4 cm⁻¹ represents the antisymmetric stretching vibration of the methylene group (-CH₂-). -1 The peak at 1431.3 cm⁻¹ represents the symmetric stretching vibration of the methylene group. -1 The peak at 1670.2 cm⁻¹ represents the bending vibration of the methylene group, indicating the presence of the methylene group. -1 The peak at 1631.9 cm⁻¹ is a characteristic absorption peak generated by the stretching vibration of the CS bond, while the high-temperature stabilizer shows a peak at 1631.9 cm⁻¹. -1 This indicates an interaction between sodium metabisulfite and sodium hydroxymethylsulfonate, 1095.8 cm. -1 The characteristic absorption peak at 1237.4 cm⁻¹ is generated by the stretching vibration of the CO bond. -1 1209.9cm -1 1186.1cm -1 Yes - SO 3- The characteristic absorption peak generated by asymmetric stretching vibration, 1042.7 cm⁻¹. -1 Yes - SO 3- Characteristic absorption peaks generated by symmetrical stretching vibrations, 518–708 cm⁻¹ -1 The continuous absorption peak at 489.1 cm⁻¹ is an absorption peak generated by the deformation vibration of the CS and SO bonds, and is a characteristic absorption peak of SS in sodium metabisulfite. -1 It is the SS bond in sodium metabisulfite.

[0067] X-ray photoelectron spectroscopy further confirmed that the product of Example 3 was a composition of hydroxyalkyl sulfonate and low-valent sulfur atom oxyacid salt. Figure 4 The XPS full scan spectrum shown indicates that the product is composed of four atoms: C, O, S, and Na. Figure 5 The fine spectrum of sulfur atoms shown contains sulfur atoms in three different chemical environments: hydroxyalkyl sulfonate, low-valent sulfur atom oxyacid salt, and sulfate (formed by oxidation of raw materials). This indicates that the product of Example 3 is a combination of hydroxyalkyl sulfonate and low-valent sulfur atom oxyacid salt.

[0068] Example 4

[0069] Sodium sulfite (50.4g, 0.40mol) and sodium thiosulfate (63.24g, 0.40mol) were dissolved in 359.2g of water. After the solution was evenly dissolved, paraformaldehyde (12g, 0.40mol) and butanone (43.26g, 0.60mol) were added. The pH value was adjusted to 8-10 with an inorganic base and added to a reaction vessel. The mixture was stirred at 400rpm for 5 hours under sealed conditions at 90℃. After cooling, depressurization, and discharge, the product was dried and pulverized to prepare a powdered product, sulfonated drilling fluid high-temperature stabilizer 4, whose main components are sodium sulfite, sodium hydroxymethyl sulfonate, and sodium 2-hydroxy-2-butyrate.

[0070] Examples 5-9

[0071] Examples 5-9 were prepared according to the components given in Table 1, and the preparation methods were consistent with those in Example 1, and high-temperature stabilizers 5-9 were prepared respectively.

[0072] Table 1. Raw material dosage and reaction conditions for Examples 5-9

[0073]

[0074] Comparative Example 1

[0075] Hydrogen peroxide was used as a high-temperature stabilizer.

[0076] Comparative Example 2

[0077] Sodium metabisulfite was used as a high-temperature stabilizer.

[0078] Comparative Example 3

[0079] Potassium sulfate was used as a high-temperature stabilizer.

[0080] Comparative Example 4

[0081] A mixture of sodium sulfite, potassium metabisulfite, acetaldehyde, and trioxymethylene in a mass ratio of 10:7:1.3:1 was used as high-temperature stabilizer 13.

[0082] The high-temperature stabilizers obtained in Examples 1-9 and Comparative Examples 1-3 were evaluated for performance in saturated brine-based slurry. The specific methods are as follows:

[0083] Freshwater-based slurry: Add 350mL of water to a high-speed mixing cup, and add 0.49g of sodium carbonate, 14g of sodium bentonite for testing and 14g of evaluation soil for testing while stirring. Stir at high speed for 20min, seal and let stand for 24h to obtain freshwater-based slurry.

[0084] Preparation of saturated brine-based slurry: Add 105g NaCl to freshwater-based slurry while stirring to obtain saturated brine-based slurry.

[0085] Experimental slurry preparation:

[0086] Experimental Slurry 1#: Under high-speed stirring, 6% SMC (sulfonated lignite, Lankao Desheng) + 6% SMP-1 (sulfonated phenolic resin, Lankao Desheng) + 1% of the high-temperature stabilizer prepared in Examples 1-9 or Comparative Examples 1-3 were added to the fresh water-based slurry. The mixture was stirred at high speed for 20 minutes. Then, 105g of NaCl was added under stirring and stirred at high speed for 20 minutes. Finally, 8.75g of Na2CO3 was added and stirred at high speed for 20 minutes to obtain the experimental slurry.

[0087] Experimental Slurry #2: Under high-speed stirring, 8% SMC (sulfonated lignite, Lankao Desheng) + 8% SMP-1 (sulfonated phenolic resin, Lankao Desheng) + 2% of the high-temperature stabilizer prepared in Examples 1-9 or Comparative Examples 1-3 were added to the fresh water-based slurry. The mixture was stirred at high speed for 20 minutes. Then, 105g of NaCl was added under stirring and stirred at high speed for 20 minutes. Finally, 8.75g of Na2CO3 was added and stirred at high speed for 20 minutes to obtain the experimental slurry.

[0088] Saturated brine-based slurries were aged at 180℃ / 16h and 200℃ / 16h, respectively. Experimental slurry #1 was aged at 180℃ / 16h, and experimental slurry #2 was aged at 200℃ / 16h. After cooling, the slurries were poured out, and their rheological properties and medium-pressure filtration loss (FL) were determined according to GB / T16783.1. API and high temperature and high pressure filtration loss FL HTHP (Test temperature 150℃, pressure 3.45MPa), the rheological properties include apparent viscosity AV, plastic viscosity PV and yield value YP, and the test results are shown in Table 2.

[0089] Table 2 Performance Evaluation of Examples and Comparative Examples

[0090]

[0091]

[0092]

[0093] As shown in Table 2, the high-temperature stabilizers 1-9 provided in this invention significantly reduce viscosity and controllable filtration loss in saturated brine sulfonated drilling fluids after their application. When the sulfonated drilling fluid undergoes high-temperature aging at 180℃ / 16h, using 1% high-temperature stabilizer reduces the apparent viscosity from 69.5 mPa·s to below 30.0 mPa·s, and the high-temperature, high-pressure filtration loss is reduced to below 30.0 mL. Using 1% hydrogen peroxide (a comparative example), the apparent viscosity decreases to 36.0 mPa·s. Using 1% sodium metabisulfite and 1% potassium sulfite also reduces the apparent viscosity to below 30.0 mPa·s, but the high-temperature, high-pressure filtration loss is greater than 45.0 mL after using the comparative product. When sulfonated drilling fluid is aged at 200℃ for 16 hours, using 2% high-temperature stabilizer can reduce the apparent viscosity from solidification to below 30.0 mPa·s, and the high-temperature, high-pressure filtration loss can be reduced to below 30.0 mL. After using the comparative example of 2% hydrogen peroxide, the apparent viscosity decreased to 76.5 mPa·s. Using 2% sodium metabisulfite and 2% potassium sulfite, the apparent viscosity decreased to below 35.0 mPa·s, but the high-temperature, high-pressure filtration loss was greater than 40.0 mL after using the comparative example product. Using a mixture of 2% sodium sulfite, potassium metabisulfite, acetaldehyde, and paraformaldehyde, the apparent viscosity decreased to 76.5 mPa·s, but the high-temperature, high-pressure filtration loss was relatively large, at 96 mL. Therefore, it can be seen that high-temperature stabilizers can effectively improve the high-temperature stability of sulfonated drilling fluids. The specific reason may be that in traditional chromium-containing high-temperature and ultra-high-temperature drilling systems, chromium mainly functions as a viscosity reducer. Raw materials for introducing chromium include potassium dichromate (K₂Cr₂O₇) and iron-chromium lignin sulfonate (FCLS), etc. Due to their unique atomic structure, such as the common Cr... 3+ The outer electron configuration is 3d 3 4s 0 Chromium has multiple coordination possibilities and can control the increase in system viscosity caused by cross-linking reactions within the sulfonated drilling fluid system, making it once considered an indispensable key treatment agent for high-temperature and ultra-high-temperature drilling fluid systems. Traditional high-temperature stabilizers need to be adapted to the special system of chromium, and comparative studies show that traditional high-temperature stabilizers cannot meet the requirements of current chromium-free high-temperature and ultra-high-temperature drilling fluids. The present invention provides a composition of oxyacid salts and hydroxyalkyl sulfonates prepared by the addition reaction of low-valent sulfur atom oxyacid salts with carbonyl compounds (aldehydes / ketones) as a high-temperature stabilizer for chromium-free high-temperature and ultra-high-temperature drilling fluid systems. By regulating the cross-linking ability of the ortho- and para-position active groups (-H and -CH2OH) of the phenolic ring of the core sulfonated treatment agent in the drilling fluid system, the treatment agent can be "appropriately cross-linked," offsetting the performance degradation caused by high-temperature degradation of the treatment agent, without causing high-temperature thickening of the system due to "excessive cross-linking."

[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 high-temperature stabilizer for sulfonated drilling fluids, comprising an oxyacid salt of low-valent sulfur and a hydroxyalkyl sulfonate, wherein the high-temperature stabilizer for sulfonated drilling fluids is prepared according to the following steps: Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions to obtain a sulfonated drilling fluid high-temperature stabilizer. The oxyacid salts of low-valent sulfur include oxyacid salts of divalent sulfur and / or oxyacid salts of tetravalent sulfur; The carbonyl compounds include aldehydes and / or ketones; The molar ratio of sulfur in the oxyacid salt of the low-valent sulfur to the carbonyl group in the carbonyl compound is (1.2 to 2.0):

1.

2. The high temperature stabilizer for sulfonated drilling fluid according to claim 1, characterized by, The oxyacid salts of low-valent sulfur include one or more of sodium metabisulfite, sodium sulfite, sodium bisulfite, potassium metabisulfite, potassium sulfite, potassium bisulfite, sodium thiosulfate, and potassium thiosulfate.

3. The high-temperature stabilizer for sulfonated drilling fluid according to claim 1, characterized in that, The carbonyl compound includes one or more of formaldehyde, paraformaldehyde, furfural, acetone, and butanone.

4. The high-temperature stabilizer for sulfonated drilling fluid according to claim 1, characterized in that, The reaction temperature is 60–100°C, and the reaction time is 2–6 hours.

5. The high-temperature stabilizer for sulfonated drilling fluid according to claim 1, characterized in that, A low-valent sulfur oxyacid salt is dissolved in water to prepare an aqueous solution with a mass concentration of 20% to 60%, and then a carbonyl compound is added.

6. The high-temperature stabilizer for sulfonated drilling fluid according to claim 1, characterized in that, The reaction was carried out under stirring conditions at a speed of 100–400 rpm.

7. A method for preparing a high-temperature stabilizer for sulfonated drilling fluid as described in any one of claims 1 to 6, comprising the following steps: Low-valent sulfur oxyacid salts and carbonyl compounds are mixed in water, and an inorganic base is added to adjust the pH to 8-10. The reaction is carried out under high temperature and sealed conditions. After the reaction is completed, the reaction product is dried and pulverized after cooling, depressurization and discharge to obtain a sulfonated drilling fluid high-temperature stabilizer.

8. The application of the high-temperature stabilizer for sulfonated drilling fluid as described in any one of claims 1 to 6 in chromium-free sulfonated water-based drilling fluid.

9. The application according to claim 8, characterized in that, The addition mass of the high-temperature stabilizer for the sulfonated drilling fluid is 1% to 40% of the total mass of the sulfonated material.

10. The application according to claim 9, characterized in that, The sulfonated materials in the chromium-free sulfonated water-based drilling fluid include sulfonated methyl phenolic resin and sulfonated lignite.

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