High-temperature stabilizer for high-density oil-based drilling fluid, preparation method and application thereof

Abstract

The application provides a high-temperature stabilizer for high-density oil-based drilling fluid, which is formed by mixed components; the mixed components comprise dodecyl benzene sulfonic acid, an alkaline compound, water, a water-in-oil emulsifier and an oil phase component; the alkaline compound is a polybasic alkali and / or an oxide corresponding to the polybasic alkali. Compared with the prior art, the high-temperature stabilizer for high-density oil-based drilling fluid contains dodecyl benzene sulfonic acid salt, which belongs to a polybasic metal soap salt and contains two or more than two hydrocarbon chains in the molecule, is more lipophilic, is suitable for use in a W / O type oil-based drilling fluid system, and makes the stabilizer have the functions of high-temperature resistance, wetting and viscosity increase, so that other auxiliary emulsifiers, wetting agents and viscosity increasing agents do not need to be added in the prepared system, the preparation is simple, field operation is convenient, and cost reduction and benefit increase are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of oil-based drilling fluid application technology for deep and ultra-deep well drilling in oil and gas, and particularly relates to a high-temperature stabilizer for high-density oil-based drilling fluid, its preparation method and application. Background Technology

[0002] With the increasing demand for oil and natural gas energy from the national economy, unconventional oil and gas, as well as ultra-deep oil and gas, have become important sources of energy supply for my country. Domestic and international efforts are continuously increasing the exploration and development of deep formation oil and gas reservoirs, leading to a rise in deep and ultra-deep wells. Drilling operations face challenges such as high formation pressure, high downhole temperatures, high water sensitivity and easy collapse in shale formations, and easy creep in salt-gypsum formations. These high-temperature, high-pressure, and easily collapsible formations require high-density drilling fluid systems resistant to high temperatures. While oil-based drilling fluid systems have advantages in terms of high-temperature resistance and inhibition, high-density oil-based drilling fluid systems also suffer from problems such as decreased emulsification performance, poor rheological properties, and sedimentation instability under high-temperature environments, which are urgent issues to be addressed.

[0003] Formulating high-density oil-based drilling fluid systems resistant to high temperatures requires not only high-temperature resistant emulsifiers but also wetting agents. Sodium dodecylbenzene sulfonate can be used as an auxiliary emulsifier with wetting properties. Chinese Patent CN111057527A discloses a high-density oil-based drilling fluid and its preparation method. The main emulsifier consists of diethylenetriamine, a higher fatty acid ester, maleic polyamide, and polyoxyethylene ether, while the auxiliary emulsifier is sodium dodecylbenzene sulfonate. This combination of main and auxiliary emulsifiers improves emulsification stability and temperature resistance, resulting in a drilling fluid density of 2.0–2.5 g / cm³. 3 However, the preparation temperature is only 150℃, which cannot fully meet the needs of high-temperature deep wells. Furthermore, sodium dodecylbenzenesulfonate is a monometallic soap with only one hydrocarbon chain in its molecule, making it more hydrophilic and prone to forming O / W type emulsions, but it is not very suitable for use in W / O type oil-based drilling fluid systems. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a high-temperature stabilizer for high-density oil-based drilling fluid that has the functions of high temperature resistance, wetting and thickening, as well as its preparation method and application.

[0005] This invention provides a high-temperature stabilizer for high-density oil-based drilling fluids, which is formed from a mixture of components; the mixture includes: dodecylbenzenesulfonic acid, an alkaline compound, water, a water-in-oil emulsifier, and an oil phase component; the alkaline compound is a polybasic base and / or an oxide corresponding to a polybasic base.

[0006] Preferably, the mixed components include:

[0007]

[0008] Preferably, the alkaline compound is selected from one or more of calcium oxide, magnesium oxide, aluminum oxide, calcium hydroxide, magnesium hydroxide, and aluminum hydroxide;

[0009] The water-in-oil emulsifier is a dehydrated sorbitan fatty acid ester;

[0010] The oil phase component is white oil.

[0011] Preferably, the water-in-oil emulsifier is selected from one or more of Span-20, Span-80, and Span-85;

[0012] The oil phase component is No. 3 white oil.

[0013] The present invention also provides a method for preparing the above-mentioned high-temperature stabilizer for high-density oil-based drilling fluid, comprising the following steps:

[0014] S1) Dodecylbenzenesulfonic acid, an alkaline compound, and a portion of the oil phase components are mixed to obtain a mixed component;

[0015] S2) Under stirring conditions, water is added to the mixed components for reaction, and then the remaining oil phase components and water-in-oil emulsifier are added to obtain a high-density oil-based drilling fluid high-temperature stabilizer.

[0016] Preferably, the mass ratio of the partial oil phase component to the remaining oil phase component is 1:(1-3);

[0017] The reaction time in step S2) is 0.5 to 1.5 hours.

[0018] The present invention also provides a high-density oil-based drilling fluid, comprising the above-mentioned high-density oil-based drilling fluid high-temperature stabilizer.

[0019] Preferably, it also includes the emulsifier shown in formula (I):

[0020]

[0021] Wherein, R1 is an alkyl group of C14 to C22; R2 is an alkylene group of C1 to C8;

[0022] A1 is a substituted or unsubstituted phenylene group or a substituted or unsubstituted heterocyclic group;

[0023] A2 and A2' are each independently selected from H or the group shown in formula (II), and are not both H;

[0024]

[0025] R3 is a substituted or unsubstituted C1-C12 alkyl group;

[0026] The substituents in the substituted phenylene and the substituted heterocyclic group are each independently selected from C1 to C5 alkyl groups;

[0027] The substituents in the substituted C1-C12 alkyl groups are selected from amino or hydroxyl groups.

[0028] Preferably, the mass of the high-temperature stabilizer for the high-density oil-based drilling fluid is 3% to 5% of the mass of the high-density oil-based drilling fluid;

[0029] The mass of the emulsifier shown in Formula (I) is 4% to 6% of the mass of the high-density oil-based drilling fluid.

[0030] Preferably, the oil-water ratio of the high-density oil-based drilling fluid is 85:15 to 95:5;

[0031] The density of the high-density oil-based drilling fluid is 2.0–2.5 g / cm³. 3 ;

[0032] The aging temperature of the high-density oil-based drilling fluid is 180℃~220℃.

[0033] This invention provides a high-density oil-based drilling fluid high-temperature stabilizer, formed from a mixture of components. The mixture comprises: dodecylbenzenesulfonic acid, an alkaline compound, water, a water-in-oil emulsifier, and an oil phase component. The alkaline compound is a polybasic base and / or its corresponding oxide. Compared with existing technologies, the dodecylbenzenesulfonate in the high-density oil-based drilling fluid high-temperature stabilizer provided by this invention is a polymetallic soap salt with two or more hydrocarbon chains in its molecule, making it more lipophilic. This not only makes it suitable for use in W / O type oil-based drilling fluid systems but also gives the stabilizer high-temperature resistance, wetting, and viscosity-enhancing functions. The formulation system does not require the addition of other emulsifiers, wetting agents, or viscosity enhancers, making preparation simple, convenient for field operation, and beneficial for cost reduction and efficiency improvement.

[0034] Furthermore, the high-temperature stabilizer for high-density oil-based drilling fluid provided by the present invention can form a synergistic effect with the emulsifier shown in formula (I) at high temperatures, further enhancing the system's resistance to high-temperature thickening, overcoming the system instability caused by demulsification and rapid decrease in system viscosity and shear caused by high temperatures, thereby maintaining the viscosity and shear required for high-density systems at high temperatures and improving the emulsification and suspension stability of the system.

[0035] Experimental results show that the density of the high-density oil-based drilling fluid prepared using the high-temperature stabilizer for oil provided in this invention and the emulsifier shown in formula (I) as the key processing agent is 2.0–2.5 g / cm³. 3The high-density oil-based drilling fluid system showed no demulsification or sedimentation after 16 hours of constant temperature rolling at 220℃, and all performance characteristics were good. It also maintained stable performance after 72 hours of constant temperature rolling at 200℃, which may provide a solution to problems such as high-temperature demulsification, poor rheological properties, and barite sedimentation of high-density oil-based drilling fluids in deep and ultra-deep well drilling. Detailed Implementation

[0036] 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.

[0037] This invention provides a high-temperature stabilizer for high-density oil-based drilling fluids, which is formed from a mixture of components; the mixture includes: dodecylbenzenesulfonic acid, an alkaline compound, water, a water-in-oil emulsifier, and an oil phase component; the alkaline compound is a polybasic base and / or an oxide corresponding to a polybasic base.

[0038] According to the present invention, the mixed components preferably include:

[0039]

[0040] According to the present invention, the content of dodecylbenzenesulfonic acid in the mixed component is preferably 80 to 120 parts by weight; in some embodiments provided by the present invention, the content of dodecylbenzenesulfonic acid in the mixed component is specifically 100 parts by weight, 80 parts by weight, 90 parts by weight, 130 parts by weight, 70 parts by weight or 120 parts by weight.

[0041] According to the present invention, the alkaline compound is a polybasic base and / or an oxide corresponding to a polybasic base; the polybasic base is preferably a polybasic weak base, more preferably one or more of calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; the oxide corresponding to the polybasic base is preferably an oxide corresponding to a polybasic weak base, more preferably one or more of calcium oxide, magnesium oxide, and aluminum oxide; dodecylbenzenesulfonic acid can react with the alkaline compound to generate dodecylbenzenesulfonic acid polymetallic soap salt with high temperature resistance and wetting effect; the content of the alkaline compound in the mixed components is preferably 6 to 10 parts by weight; in some embodiments provided by the present invention, the content of the alkaline compound in the mixed components is specifically 6 parts by weight, 9 parts by weight, 8 parts by weight, 10 parts by weight, or 4 parts by weight.

[0042] According to the present invention, the water is preferably purified water; the water content in the mixed components is preferably 6 to 8 parts by weight; in some embodiments provided by the present invention, the water content in the mixed components is specifically 8 parts by weight, 6 parts by weight, 7 parts by weight, 9 parts by weight, or 5 parts by weight.

[0043] According to the present invention, the water-in-oil emulsifier is preferably a sorbitan fatty acid ester, which has emulsifying and thickening effects. Through emulsification, it can promote the compatibility of the components of the product, making the product more uniform and stable. In the present invention, it is more preferably one or more of Span-20, Span-80 and Span-85. The content of the water-in-oil emulsifier in the mixed components is preferably 7 to 11 parts by weight. In some embodiments provided by the present invention, the content of the water-in-oil emulsifier in the mixed components is specifically 10 parts by weight, 7 parts by weight, 9 parts by weight, 12 parts by weight, 6 parts by weight or 11 parts by weight.

[0044] The oil phase component serves to disperse and dilute, giving the high-temperature stabilizer good fluidity for easy on-site use. In this invention, the oil phase component is preferably white oil, more preferably No. 3 white oil. The content of the oil phase component in the mixed component is preferably 40 to 60 parts by weight. In some embodiments provided by this invention, the content of the oil phase component in the mixed component is specifically 50 parts by weight, 40 parts by weight, 45 parts by weight, 65 parts by weight, 35 parts by weight, or 60 parts by weight.

[0045] The high-density oil-based drilling fluid high-temperature stabilizer provided by this invention contains dodecylbenzene sulfonate, which is a multi-metal soap salt with two or more hydrocarbon chains in its molecule. It is more lipophilic and not only suitable for use in W / O type oil-based drilling fluid systems, but also gives the stabilizer the functions of high temperature resistance, wetting, and thickening. The formulation system does not require the addition of other emulsifiers, wetting agents, and thickeners. It is simple to formulate, convenient for field operation, and conducive to cost reduction and efficiency improvement.

[0046] The present invention also provides a method for preparing the above-mentioned high-density oil-based drilling fluid high-temperature stabilizer, comprising the following steps: S1) mixing dodecylbenzene sulfonic acid, an alkaline compound and a portion of the oil phase components to obtain a mixed component; S2) adding water to the mixed component under stirring to react, and then adding the remaining oil phase components and a water-in-oil emulsion to obtain the high-density oil-based drilling fluid high-temperature stabilizer.

[0047] The present invention does not impose any special restrictions on the source of the raw materials, as long as they are commercially available; the types and contents of the dodecylbenzenesulfonic acid, basic compound, oil phase component, water and water-in-oil emulsifier are the same as those described above, and will not be repeated here.

[0048] Dodecylbenzenesulfonic acid, an alkaline compound, and a portion of the oil phase components were mixed to obtain a mixed component.

[0049] Water is added to the mixture under stirring conditions to carry out the reaction; the stirring speed is preferably 200-350 rpm, more preferably 220-320 rpm, and even more preferably 250-300 rpm; since the reaction after adding water is an exothermic reaction, the heat generated can promote the reaction between dodecylbenzenesulfonic acid and the basic compound; in this invention, the water is preferably added slowly to control the reaction rate and make the reaction more gentle; the reaction time is preferably 0.5-1.5 h, more preferably 0.8-1.5 h.

[0050] Then, the remaining oil phase component and water-in-oil emulsifier are added to obtain a high-density oil-based drilling fluid high-temperature stabilizer; the mass ratio of the partial oil phase component to the remaining oil phase component is preferably 1:(1-3), more preferably 1:(1.6-2.5); in some embodiments provided by the present invention, the mass ratio of the partial oil phase component to the remaining oil phase component is specifically 1:2, 3:7, 3:5, 4:9 or 1:2.5; in the present invention, it is preferred to add the remaining oil phase component first, and then add the water-in-oil emulsifier; after adding the water-in-oil emulsifier, it is preferred to stir for 1-2 hours to obtain a high-density oil-based drilling fluid high-temperature stabilizer.

[0051] The method for preparing high-temperature stabilizers for high-density oil-based drilling fluids provided by this invention is simple, easy to operate, and can be completed through a self-heating reaction without the need for heating equipment. It is energy-saving, environmentally friendly, and convenient for production.

[0052] The high-temperature stabilizer prepared by this invention is a milky white to light yellow liquid. It is obtained by neutralizing dodecylbenzenesulfonic acid with a polybasic base to obtain anionic surfactant dodecylbenzenesulfonic acid polymetallic soap salt with high temperature resistance and wetting function. The dehydrated sorbitan fatty acid ester is a nonionic surfactant with emulsifying and thickening functions. During the product preparation process, it can promote the compatibility of each component through emulsification, making the product more uniform and stable. The white oil plays a role in dispersing and diluting, so that the product has good fluidity and is easy to use on site.

[0053] The present invention also provides a high-density oil-based drilling fluid, comprising the above-mentioned high-density oil-based drilling fluid high-temperature stabilizer.

[0054] According to the present invention, the mass of the high-temperature stabilizer for the high-density oil-based drilling fluid is preferably 3% to 5% of the mass of the high-density oil-based drilling fluid.

[0055] According to the present invention, the high-density oil-based drilling fluid preferably further includes an emulsifier represented by formula (I):

[0056]

[0057] Wherein, R1 is a C9 to C22 alkyl group, preferably a C14 to C22 alkyl group; R2 is a C1 to C8 alkylene group.

[0058] A1 is a substituted or unsubstituted phenylene group or a substituted or unsubstituted heterocyclic group; the substituents in the substituted phenylene group and the substituted heterocyclic group are each independently a C1-C5 alkyl group, preferably a C1-C3 alkyl group, more preferably a methyl group; the heterocyclic group is preferably a heterocyclic five-membered ring group or a heterocyclic six-membered ring group; the heteroatom in the heterocyclic group can be a heteroatom well known to those skilled in the art, and there are no special restrictions. In this invention, O, S, or N are preferred; in this invention, the heterocyclic group is preferably a pyridylene group; A1 is most preferably a tolylene group or a pyridylene group, and more specifically:

[0059]

[0060] A2 and A2' are each independently H or the group shown in formula (II), and are not both H.

[0061]

[0062] R3 is a substituted or unsubstituted C1-C12 alkyl group; the substituent in the substituted C1-C12 alkyl group is preferably an amino or hydroxyl group.

[0063] In this invention, the emulsifier represented by formula (I) is preferably prepared according to the following steps: a diamino compound is mixed with a diacid and heated to react, then a fatty amine is added and the reaction is continued to be heated, and finally an alkyl sulfonic acid compound is added and reacted to obtain the emulsifier represented by formula (I); the diamino compound is preferably diaminotoluene and / or diaminopyridine, more preferably 2,6-diaminotoluene and / or 2,6-diaminopyridine; the diacid is preferably one or more of C3-C10 dicarboxylic acids, more preferably one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, and sebacic acid; the fatty amine is preferably one or more of C9-C22 fatty amines, more preferably one or more of C14-C22 fatty amines, and even more preferably one or more of tetradecylamine, hexadecylamine, oleylamine, octadecylamine, eicosamine, and dodecylamine; the number of carbon atoms in the alkyl sulfonic acid compound is preferably 1- 12; In this invention, the alkyl sulfonic acid compound is preferably one or more of methanesulfonic acid, taurine, 3-hydroxypropanesulfonic acid, 1-butanesulfonic acid, hexane sulfonate, octyl sulfonic acid, dodecyl sulfonic acid, and dodecylbenzene sulfonic acid; the molar ratio of the diamino compound, dicarboxylic acid, fatty amine, and alkyl sulfonic acid compound is preferably 1:(1.5-2):(0.5-1):(1-2); the temperature of the mixed heating reaction, the continued heating reaction, and the reaction with the addition of the alkyl sulfonic acid compound are each preferably 140°C to 180°C; the time of the mixed heating reaction, the continued heating reaction, and the reaction with the addition of the alkyl sulfonic acid compound are each preferably 2-4 hours; the mixed heating reaction, the continued heating reaction, and the reaction with the addition of the alkyl sulfonic acid compound are preferably carried out under stirring conditions; after the reaction with the addition of the alkyl sulfonic acid compound, it is preferably cooled to room temperature to obtain a black-brown solid emulsifier, which is the emulsifier shown in formula (I).

[0064] The emulsifier shown in Formula (I) is preferably 4% to 6% of the mass of the high-density oil-based drilling fluid.

[0065] The high-density oil-based drilling fluid high-temperature stabilizer provided by the present invention can form a synergistic effect with the emulsifier shown in formula (I) at high temperature, further enhancing the system's resistance to high-temperature thickening, overcoming the system instability caused by demulsification and rapid decrease in system viscosity and shear caused by high temperature, thereby maintaining the viscosity and shear required for the high-density system at high temperature and thus improving the system's emulsification and suspension stability.

[0066] According to the present invention, the high-density oil-based drilling fluid preferably further includes base oil; the base oil is preferably diesel oil and / or white oil, more preferably 0# diesel oil or 3# white oil.

[0067] According to the present invention, the high-density oil-based drilling fluid preferably further includes an aqueous phase; the aqueous phase is preferably an aqueous solution of calcium chloride; the mass concentration of the aqueous solution of calcium chloride is preferably 20% to 30%, more preferably 25%.

[0068] According to the present invention, the oil-water ratio of the high-density oil-based drilling fluid is preferably 85:15 to 95:5.

[0069] According to the present invention, the high-density oil-based drilling fluid preferably further includes a viscosifier; the content of the viscosifier in the high-density oil-based drilling fluid is preferably 4-8 g / mL, more preferably 4-7.6 g / mL; the viscosifier can be any viscosifier known to those skilled in the art, and there are no special limitations, but in the present invention, organic clay is preferred.

[0070] According to the present invention, the high-density oil-based drilling fluid preferably further includes a filtration loss reducer; the content of the filtration loss reducer in the high-density oil-based drilling fluid is preferably 3-13 g / mL, more preferably 5-10 g / mL, even more preferably 7-9 g / mL, and most preferably 8 g / mL; the filtration loss reducer can be any filtration loss reducer known to those skilled in the art, and there are no special restrictions. In the present invention, oxidized asphalt is preferred.

[0071] According to the present invention, the high-density oil-based drilling fluid preferably further includes an alkalinity regulator; the content of the alkalinity regulator in the high-density oil-based drilling fluid is preferably 3-10 g / mL, more preferably 5-8 g / mL, and even more preferably 6 g / mL; the alkalinity regulator is preferably calcium oxide and / or magnesium oxide.

[0072] According to the present invention, the high-density oil-based drilling fluid preferably further includes a weighting agent; the density of the drilling fluid is adjusted by the weighting agent; the weighting agent can be any weighting agent known to those skilled in the art, and there are no special restrictions. In the present invention, one or more of barite, iron ore powder and manganese tetroxide are preferred.

[0073] According to the present invention, the density of the high-density oil-based drilling fluid is preferably 2.0–2.5 g / cm³. 3 .

[0074] According to the present invention, the aging temperature of the high-density oil-based drilling fluid is preferably 180℃~220℃.

[0075] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, provides a high-density oil-based drilling fluid high-temperature stabilizer, its preparation method, and its application.

[0076] All reagents used in the following examples were commercially available and strictly adhered to industry standards. Specifically, dodecylbenzenesulfonic acid (96% effective content) was purchased from Linyi Lusen Chemical Co., Ltd., industrial grade; sorbitan fatty acid ester was purchased from Jiangsu Haian Petrochemical Plant, industrial grade; calcium oxide, magnesium oxide, aluminum oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and sodium dodecylbenzenesulfonate were all purchased from Sinopharm Reagent, chemically pure; white oil was purchased from Hubei Jingmen Petrochemical's No. 3 white oil, industrial grade; and oxidized asphalt was from Puyang Meijing Chemical Materials Co., Ltd. The high-temperature emulsifiers used in Examples 7-12 were prepared according to Example 1 of Chinese Patent Application No. 2021114686473.

[0077] The performance of the high-density oil-based drilling fluid high-temperature stabilizer prepared in the following examples will be reflected by the sedimentation stability, rheological properties, and electrical stability of the high-density oil-based drilling fluid after high-temperature aging.

[0078] Example 1

[0079] In a reactor equipped with a stir bar and a thermometer, 100g of dodecylbenzenesulfonic acid, 15g of white oil, and 6g of magnesium oxide were added and stirred until homogeneous. After the solid and liquid were mixed evenly, 8g of purified water was slowly added dropwise while stirring and reacted for 0.8h. After the reaction was completed, 35g of white oil was added and mixed evenly. Finally, 10g of Span-85 was added and stirred for 1h to obtain high-temperature stabilizer W1.

[0080] Example 2

[0081] In a reactor equipped with a stir bar and a thermometer, 80g of dodecylbenzenesulfonic acid, 15g of white oil, and 9g of calcium hydroxide were added and stirred until homogeneous. After the solid and liquid were mixed evenly, 6g of purified water was slowly added dropwise while stirring and reacted for 1 hour. After the reaction was completed, 25g of white oil was added and mixed evenly. Finally, 7g of Span-80 was added and stirred for 1.5 hours to obtain high-temperature stabilizer W2.

[0082] Example 3

[0083] In a reactor equipped with a stir bar and a thermometer, 90g of dodecylbenzenesulfonic acid and 15g of white oil were added and stirred until homogeneous. Then, 8g of magnesium hydroxide was slowly added while stirring. After the solid and liquid were mixed evenly, 7g of purified water was slowly added dropwise while stirring and reacted for 1.5h. After the reaction was completed, 30g of white oil was added and mixed evenly. Finally, 9g of Span-85 was added and stirred for 2h to obtain high-temperature stabilizer W3.

[0084] Example 4

[0085] In a reactor equipped with a stir bar and a thermometer, 130g of dodecylbenzenesulfonic acid and 20g of white oil were added and stirred until homogeneous. Then, 10g of aluminum hydroxide was slowly added while stirring. After the solid and liquid were mixed evenly, 9g of purified water was slowly added dropwise while stirring and reacted for 1 hour. After the reaction was completed, 45g of white oil was added and mixed evenly. Finally, 12g of Span-20 was added and stirred for 1 hour to obtain high-temperature stabilizer W4.

[0086] Example 5

[0087] In a reactor equipped with a stir bar and a thermometer, 70g of dodecylbenzenesulfonic acid and 10g of white oil were added and stirred until homogeneous. Then, 4g of alumina was slowly added while stirring. After the solid and liquid were mixed evenly, 5g of purified water was slowly added dropwise while stirring and reacted for 1.5h. After the reaction was completed, 25g of white oil was added and mixed evenly. Finally, 6g of Span-80 was added and stirred for 2h to obtain high-temperature stabilizer W5.

[0088] Example 6

[0089] In a reactor equipped with a stir bar and a thermometer, 120g of dodecylbenzenesulfonic acid and 20g of white oil were added and stirred until homogeneous. Then, 10g of calcium oxide was slowly added while stirring. After the solid and liquid were mixed evenly, 8g of purified water was slowly added dropwise while stirring and reacted for 1 hour. After the reaction was completed, 40g of white oil was added and mixed evenly. Finally, 11g of Span-20 was added and stirred for 2 hours to obtain high-temperature stabilizer W6.

[0090] Example 7

[0091] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.2 g / cm³) 3 ):

[0092] Base solution (No. 3 white oil): 170mL;

[0093] 20 mL of 25% CaCl2 aqueous solution;

[0094] And based on the total volume fraction (190 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0095] Organic soil: 7.6 g / mL;

[0096] High-temperature resistant solid emulsifier: 11.4 g / mL;

[0097] High-temperature stabilizer (prepared in Example 1): 5.7 g / mL;

[0098] Oxidized asphalt (filtration loss reducer): 7.6 g / mL;

[0099] Calcium oxide: 5.7 g / mL;

[0100] Barite: 550g / mL.

[0101] Preparation method:

[0102] Add the specified volume fraction of base fluid #3 white oil to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes. Next, add the specified volume fraction of organic clay and stir at high speed for 5 minutes. Then, add the specified volume fraction of filtration loss reducer and stir at high speed for 5 minutes. Next, add the specified volume fraction of CaO and stir at high speed for 5 minutes. Then, add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes. Finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.2 g / cm³. 3 Stir at high speed for 20 minutes, then put into an aging tank and roll age at 200℃ for 16 hours to obtain a high-density oil-based drilling fluid resistant to high temperature.

[0103] Example 8

[0104] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.5 g / cm³) 3 ):

[0105] Base fluid (0# diesel): 180mL;

[0106] 20 mL of 25% CaCl2 aqueous solution;

[0107] And based on the total volume fraction (200 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0108] Organic soil: 4g / mL;

[0109] High-temperature resistant solid emulsifier: 8 g / mL;

[0110] High-temperature stabilizer (prepared in Example 2): 10 g / mL;

[0111] Oxidized asphalt (filtration loss reducer): 8 g / mL;

[0112] Calcium oxide: 6 g / mL;

[0113] Barite: 850g / mL.

[0114] Preparation method:

[0115] Add the specified volume fraction of base fluid #0 diesel to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes; then add the specified volume fraction of organic clay and stir at high speed for 5 minutes; then add the specified volume fraction of filtration loss reducer and stir at high speed for 5 minutes; then add the specified volume fraction of CaO and stir at high speed for 5 minutes; then add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes; finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.5 g / cm³. 3 Stir at high speed for 20 minutes, then pour into an aging tank and roll age at 180℃ for 16 hours to obtain a high-density oil-based drilling fluid resistant to high temperatures.

[0116] Example 9

[0117] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.4 g / cm³) 3 ):

[0118] Base fluid (0# diesel): 190mL;

[0119] 10 mL of 25% CaCl2 aqueous solution;

[0120] And based on the total volume fraction (200 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0121] Organic soil: 4g / mL;

[0122] High-temperature resistant solid emulsifier: 12g / mL;

[0123] High-temperature stabilizer (prepared in Example 3): 9 g / mL;

[0124] Oxidized asphalt (filtration loss reducer): 8 g / mL;

[0125] Calcium oxide: 6 g / mL;

[0126] Barite: 740 g / mL.

[0127] Preparation method:

[0128] Add the specified volume fraction of base fluid #0 diesel to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes; then add the specified volume fraction of organic clay and stir at high speed for 5 minutes; then add the specified volume fraction of filtration loss reducer and stir at high speed for 5 minutes; then add the specified volume fraction of CaO and stir at high speed for 5 minutes; then add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes; finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.4 g / cm³. 3 Stir at high speed for 20 minutes, then pour into an aging tank and roll age at 220℃ for 16 hours to obtain a high-density oil-based drilling fluid resistant to high temperatures.

[0129] Example 10

[0130] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.5 g / cm³) 3 ):

[0131] Base solution (No. 3 white oil): 180mL;

[0132] 20 mL of 25% CaCl2 aqueous solution;

[0133] And based on the total volume fraction (200 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0134] Organic soil: 4g / mL;

[0135] High-temperature resistant solid emulsifier: 12g / mL;

[0136] High-temperature stabilizer (prepared in Example 4): 10 g / mL;

[0137] Oxidized asphalt (filtration loss reducer): 8 g / mL;

[0138] Calcium oxide: 6 g / mL;

[0139] Barite: 850g / mL.

[0140] Preparation method:

[0141] Add the specified volume fraction of base fluid #3 white oil to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes. Next, add the specified volume fraction of organic clay and stir at high speed for 5 minutes. Then, add the specified volume fraction of filtration loss reducer and stir at high speed for 5 minutes. Next, add the specified volume fraction of CaO and stir at high speed for 5 minutes. Then, add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes. Finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.5 g / cm³. 3 Stir at high speed for 20 minutes, then put into an aging tank and roll age at 210℃ for 16 hours to obtain a high-density oil-based drilling fluid resistant to high temperature.

[0142] Example 11

[0143] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.3 g / cm³) 3 ):

[0144] Base fluid (0# diesel): 170mL;

[0145] 30 mL of 25% CaCl2 aqueous solution;

[0146] And based on the total volume fraction (200 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0147] Organic soil: 6 g / mL;

[0148] High-temperature resistant solid emulsifier: 10 g / mL;

[0149] High-temperature stabilizer (prepared in Example 5): 8 g / mL;

[0150] Oxidized asphalt (filtration loss reducer): 8 g / mL;

[0151] Calcium oxide: 6 g / mL;

[0152] Barite: 640g / mL.

[0153] Preparation method:

[0154] Add the specified volume fraction of base fluid #0 diesel to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes; then add the specified volume fraction of organic clay and stir at high speed for 5 minutes; then add the specified volume fraction of filtration reducer and stir at high speed for 5 minutes; then add the specified volume fraction of CaO and stir at high speed for 5 minutes; then add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes; finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.3 g / cm³. 3 Stir at high speed for 20 minutes, then pour into an aging tank and roll age at 190℃ for 16 hours to obtain a high-density oil-based drilling fluid resistant to high temperatures.

[0155] Example 12

[0156] A high-density oil-based drilling fluid formulation resistant to high temperatures (prepared density 2.4 g / cm³) 3 ):

[0157] Base solution (No. 3 white oil): 180mL;

[0158] 20 mL of 25% CaCl2 aqueous solution;

[0159] And based on the total volume fraction (200 parts) of the base liquid and the CaCl2 aqueous solution, the components are defined by the following mass-volume ratios:

[0160] Organic soil: 4g / mL;

[0161] High-temperature resistant solid emulsifier: 12g / mL;

[0162] High-temperature stabilizer (prepared in Example 6): 10 g / mL;

[0163] Oxidized asphalt (filtration loss reducer): 8 g / mL;

[0164] Calcium oxide: 8 g / mL;

[0165] Barite: 730g / mL.

[0166] Preparation method:

[0167] Add the specified volume fraction of base fluid #3 white oil to a high-speed stirring cup, then add the specified volume fraction of high-temperature resistant solid emulsifier while stirring at high speed for 10 minutes (stirring speed 11000 r / min, the same below). Then, under high-speed stirring, add the specified volume fraction of CaCl2 aqueous solution and stir at high speed for 20 minutes. Next, add the specified volume fraction of organic clay and stir at high speed for 5 minutes. Then, add the specified volume fraction of filtration loss reducer and stir at high speed for 5 minutes. Next, add the specified volume fraction of CaO and stir at high speed for 5 minutes. Then, add the specified volume fraction of high-temperature stabilizer and stir at high speed for 10 minutes. Finally, add the specified volume fraction of barite to adjust the drilling fluid density to 2.4 g / cm³. 3 Stir at high speed for 20 minutes.

[0168] Prepare three identical portions of the slurry according to the above preparation method:

[0169] The first batch was placed in an aging tank and aged at 200°C for 16 hours.

[0170] The second portion was placed in an aging tank and aged at 200°C for 72 hours.

[0171] The third portion was placed in an aging tank and aged at 200℃ for 16 hours. It was then removed and cooled to about 60℃. After stirring at high speed for 10 minutes, it was placed back into the aging tank and allowed to stand at 200℃ for 24 hours. After standing, it was removed and allowed to cool naturally to about 60℃ before opening the tank. A glass rod was then placed into the aging tank to observe the sedimentation stability of the slurry.

[0172] This embodiment aims to simultaneously test the long-term high-temperature resistance and settling stability of the provided high-temperature, high-density oil-based drilling fluid system.

[0173] Comparative Example 1

[0174] A high-density oil-based drilling fluid resistant to high temperatures was prepared according to the method described in Example 12, except that no high-temperature stabilizer was added.

[0175] Comparative Example 2

[0176] A high-density oil-based drilling fluid resistant to high temperatures was prepared according to the method described in Example 12. The difference from Example 12 was that 10g of high-temperature stabilizer was replaced with 10g of sodium dodecylbenzenesulfonate (Sinopharm Reagent, chemically pure).

[0177] Example 13

[0178] According to the method of national standard GB / T 16783.2-2012 "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 2: Oil-based Drilling Fluids", the high-temperature resistance performance of the high-density oil-based drilling fluids prepared in Examples 7-12 and Comparative Examples 1-2 was tested. The test results are shown in Table 1.

[0179] Table 1. Test results of high-temperature resistance of high-density oil-based drilling fluid

[0180]

[0181] Note: AV is apparent viscosity, PV is plastic viscosity, YP is dynamic shear strength, and Q is... 10s For initial cutting, HTHP FL ES represents the high-temperature, high-pressure filtration loss, and ES represents the demulsification voltage.

[0182] As shown in Table 1, the high-density oil-based drilling fluid high-temperature stabilizer provided by this invention has the functions of high-temperature resistance, wetting, and thickening. When used in combination with a high-temperature resistant emulsifier, it can formulate a high-density oil-based drilling fluid system with high-temperature resistance at a temperature of 180℃~220℃ and a density of 2.2~2.5g / cm³. 3 Within the specified range, the system maintains excellent emulsification stability, suspension stability, and rheological properties. Even after 72 hours of constant-temperature rolling at 200°C, all properties remain stable, and after 16 hours of rolling at 200°C followed by 24 hours of settling, it can be easily stirred. A comparison of data from Example 12 and Comparative Example 1 shows that the present invention has a good synergistic effect with the high-temperature resistant emulsifier, enabling the high-density oil-based drilling fluid system to have better temperature resistance and emulsification and suspension stability, meeting the needs of high-temperature deep well drilling. A comparison of data from Example 12 and Comparative Example 2 shows that the high-temperature stabilizer containing dodecylbenzenesulfonic acid multi-metal soap salts exhibits significantly better emulsification stability in high-temperature oil-based drilling fluid systems than sodium dodecylbenzenesulfonate.

[0183] The preferred embodiments of the present invention disclosed above are merely for illustrating the present invention, and the present invention is not limited thereto. Those skilled in the art will understand that, within the scope of the present invention's concept, modifications can be made to the technical solutions of the present invention, or some technical features can be combined in any other way. Such modifications or combinations do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the various embodiments of the present invention, and should be considered as the content disclosed in the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A high-temperature stabilizer for high-density oil-based drilling fluids, characterized in that, Formed from a mixture of components; The mixed components include: 70-130 parts by weight of dodecylbenzenesulfonic acid; 4-10 parts by weight of alkaline compound; 5-9 parts by weight of water; 6-12 parts by weight of water-in-oil emulsifier; Oil phase component 35~65 parts by weight; The alkaline compound is selected from one or more of calcium oxide, magnesium oxide, aluminum oxide, calcium hydroxide, magnesium hydroxide, and aluminum hydroxide. The water-in-oil emulsifier is a dehydrated sorbitan fatty acid ester; The oil phase component is white oil.

2. The high-density oil-based drilling fluid high-temperature stabilizer according to claim 1, characterized in that, The water-in-oil emulsifier is selected from one or more of Span-20, Span-80 and Span-85; The oil phase component is No. 3 white oil.

3. A method for preparing a high-temperature stabilizer for high-density oil-based drilling fluid as described in claim 1, characterized in that, Includes the following steps: S1) Dodecylbenzenesulfonic acid, an alkaline compound, and a portion of the oil phase components are mixed to obtain a mixed component; S2) Under stirring conditions, water is added to the mixed components for reaction, and then the remaining oil phase components and water-in-oil emulsifier are added to obtain a high-density oil-based drilling fluid high-temperature stabilizer.

4. The preparation method according to claim 3, characterized in that, The mass ratio of the partial oil phase component to the remaining oil phase component is 1:(1~3). The reaction time in step S2) is 0.5~1.5 h.

5. A high-density oil-based drilling fluid, characterized in that, This includes the high-density oil-based drilling fluid high-temperature stabilizer as described in claim 1 or 2, or the high-density oil-based drilling fluid high-temperature stabilizer prepared by the preparation method described in claim 3 or 4.

6. The high-density oil-based drilling fluid according to claim 5, characterized in that, It also includes the emulsifier shown in formula (I): Formula (I); Wherein, R1 is an alkyl group of C14 to C22; R2 is an alkylene group of C1 to C8; A1 is a substituted or unsubstituted phenylene group or a substituted or unsubstituted heterocyclic group; A2 and A2' are each independently selected from H or the group shown in formula (II), and are not both H; Formula (II); R3 is a substituted or unsubstituted C1~C12 alkyl group; The substituents in the substituted phenylene and the substituted heterocyclic group are each independently selected from C1 to C5 alkyl groups; The substituents in the substituted C1-C12 alkyl groups are selected from amino or hydroxyl groups.

7. The high-density oil-based drilling fluid according to claim 6, characterized in that, The mass of the high-temperature stabilizer for the high-density oil-based drilling fluid is 3% to 5% of the mass of the high-density oil-based drilling fluid. The mass of the emulsifier shown in Formula (I) is 4% to 6% of the mass of the high-density oil-based drilling fluid.

8. The high-density oil-based drilling fluid according to claim 5, characterized in that, The oil-water ratio of the high-density oil-based drilling fluid is 85:15 to 95:5; The density of the high-density oil-based drilling fluid is 2.0~2.5 g / cm³. 3 ; The aging temperature of the high-density oil-based drilling fluid is 180℃~220℃.

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