Composition of maleated fatty acids and their derivatives and ultra-high temperature oil-based drilling fluid

Abstract

The present invention discloses a composition of maleated fatty acids and their derivatives, which takes maleated fatty acids, maleated fatty-based imidazoline amides, and maleated fatty acid alkanolamides as active components, and uses a solvent oil and alcohol ether mixture as a solvent. The present invention also discloses a drilling fluid using this composition as an emulsifier. The composition of maleated fatty acids and their derivatives provided by the present invention, as an emulsifier, after hot rolling at 240 °C, has an emulsification rate of 85%, a wetting rate of 94%, and a demulsification voltage of 570 V for oil-based drilling fluids, and has the functions of emulsification and wetting in one body.

Description

Technical Field

[0001] The present invention relates to compositions of maleated fatty acids and their derivatives and ultra-high temperature oil-based drilling fluids. Background Art

[0002] Ultra-deep oil and gas resources and geothermal resources are important components of natural energy. In exploration wells and development wells for ultra-deep oil and gas resources at depths of 8000 m or more, even 9000 m or more, the target formation temperature will reach 200°C to 240°C. At the same time, due to complex geological conditions, the development of thick salt gypsum layers, thick steep mud shale layers and high-pressure brine layers, abnormal high-pressure layers will be frequently encountered.

[0003] Oil-based drilling fluids are considered to be the preferred drilling fluid technology for ultra-deep wells and ultra-deep wells because of their good high-temperature and high-pressure stability, good inhibition of water-sensitive mud shale layers, high chemical inertness and large pollution tolerance to salt gypsum layers and high-pressure brine layers. Oil-based drilling fluid is an oil-in-water inverse emulsion, which is a thermodynamically unstable system. Under high-temperature environments, with the degradation of emulsifier molecules and the intensification of thermal motion, the strength of the interfacial film is reduced or destroyed, reducing the stability of the oil-in-water drilling fluid. Therefore, the emulsification stability under high-temperature and ultra-high temperature environments is the basis for the field application of ultra-high temperature oil-based drilling fluids and is crucial for the performance of ultra-high temperature drilling fluids.

[0004] The main mechanisms for destroying the stability of emulsions are the coarsening and coalescence of emulsion droplets. To prevent coarsening and coalescence, the emulsifier must provide an effective repulsive force (the combined action of van der Waals force, steric effect, electrostatic force and spatial effect) at the droplet interface, which is crucial for the stability of emulsions and the structural strength of oil-in-water emulsions. Research results at home and abroad generally believe that the influence of interfacial tension on the long-term overall stability of emulsions is not as important as the properties of the interfacial film. The interfacial film can withstand the contact pressure of emulsion droplets and prevent the dispersed phase from entering the continuous phase. Its ability to establish a potential barrier (physical or electrical) for droplet contact is the main characteristic determining the ultimate stability of emulsions. The emulsifier is the main substance for forming the interfacial film and is the key to the long-term stability of oil-in-water emulsions.

[0005] As an emulsifier for oil-in-water emulsions, its HLB value ranges from 4 to 6. In oil-in-water drilling fluids, the emulsifier needs to maintain emulsification stability under more demanding conditions (high temperature and high pressure, salt gypsum solids, high salinity salt solutions and hydrophilic solids). The emulsifier should be able to completely cover the emulsion droplets to reduce the possible flocculation caused by the exposed surface; at the same time, the emulsifier molecules should have a strong adsorption or anchoring effect on the droplet surface; the hydrophobic chain segments of the emulsifier should have a strong solvation effect on the continuous phase to provide effective steric stability; on the surface of the emulsion droplets, the emulsifier should also have a reasonable adsorption thickness to prevent weak flocculation of the emulsion droplets.

[0006] The common emulsifiers for water-in-oil drilling fluids mainly include fatty acid soaps, fatty group / (aryl) calcium sulfonates, fatty group polyamines, and polyamidoamine, etc. In production applications, they are usually mixtures of multiple surfactants. The above common emulsifiers far cannot meet the on-site requirements in terms of high-temperature resistance performance and drilling fluid rheology. The high-temperature-resistant emulsifier synthesized by amidation reaction of organic acids, organic amines, and polyhydroxy acids can withstand a temperature of 210°C. The emulsifier prepared by reacting maleic anhydride with oleic acid and further reacting with diethanolamine can be used for formulating oil-based drilling fluids with a temperature resistance of 200°C. None of the above can meet the technical performance requirements of ultra-high-temperature oil-based drilling fluids at 200°C - 240°C. To meet the exploration and development of ultra-deep oil and gas resources and the safe and rapid construction of ultra-deep wells and ultra-deep special wells, it is very important to provide an emulsifier at ultra-high temperatures and formulate ultra-high-temperature oil-based drilling fluids. Summary of the Invention

[0007] The present invention aims to provide a composition of maleated fatty acids and their derivatives, which can be used as an emulsifier in ultra-high-temperature oil-based drilling fluids and meet the technical performance requirements of ultra-high-temperature oil-based drilling fluids at 200°C - 240°C.

[0008] As an aspect of the present invention, it relates to a composition of maleated fatty acids and their derivatives, with maleated fatty acids, maleated fatty group imidazoline amides, and maleated fatty acid alkanolamides as effective components, and a solvent oil (it is recommended to use an environmentally friendly type) and an alcohol ether mixture as the solvent.

[0009] In at least one embodiment, the maleated fatty acid is formed by reacting natural plant fatty acids rich in unsaturated bonds (such as oleic acid, linoleic acid, linolenic acid, palmitic acid, and rosin acid, etc.) with maleic anhydride (maleic acid anhydride) under high-temperature or catalytic conditions. Preferably, it is tall oil fatty acid rich in unsaturated fatty acids such as oleic acid, linoleic acid, and rosin acid (Shanghai Lisen Chemical Co., Ltd., the same below). Under high-temperature conditions, through a diene synthesis reaction or an ene reaction, maleic anhydride (Sinopharm Group) is grafted onto tall oil fatty acid to prepare maleated tall oil fatty acid.

[0010] In at least one embodiment, the maleated fatty group imidazoline amide is formed by reacting natural plant fatty acids rich in unsaturated bonds (such as oleic acid, linoleic acid, linolenic acid, palmitic acid, and rosin acid, etc.) with diethylenetriamine (Nanjing Gutian Chemical), through intermolecular dehydration amidation and intramolecular dehydration cyclization under high-temperature or catalytic conditions; and then reacting with maleic anhydride (maleic acid anhydride) under high-temperature or catalytic conditions to form maleated fatty group imidazoline amide. Preferably, it is tall oil fatty acid rich in unsaturated fatty acids such as oleic acid, linoleic acid, and rosin acid and diethylenetriamine, with a molar ratio greater than 2:1. Through two-step reactions of intermolecular dehydration amidation and intramolecular dehydration cyclization under high-temperature or catalytic conditions, and then reacting with maleic anhydride at high temperature to generate maleated tall oil fatty group imidazoline amide.

[0011] In at least one embodiment, the maleated fatty acid alkanolamide is obtained by reacting a natural plant fatty acid rich in unsaturated bonds (such as oleic acid, linoleic acid, linolenic acid, palmitic acid, and rosin acid) with maleic anhydride (cis-butenedioic anhydride) under catalytic conditions to form a maleated fatty acid, and then reacting with a hydroxyethyl mono-substituted or di-substituted organic amine to obtain the maleated fatty acid alkanolamide. Preferably, tall oil fatty acid rich in unsaturated fatty acids such as oleic acid, linoleic acid, and rosin acid is used. Under high-temperature conditions, through a Diels-Alder reaction or an ene reaction, maleic anhydride is grafted onto the tall oil fatty acid to prepare maleated tall oil fatty acid, and then it continues to react with monoethanolamine to prepare maleated tall oil fatty acid alkanolamide.

[0012] In at least one embodiment, the solvent oil is a de-aromatic solvent oil mainly composed of alkanes and naphthenes, preferably solvent oil D140 (Changzhou Heshili Chemical Co., Ltd.).

[0013] In at least one embodiment, the alcohol ether is a polyol ether-based polar organic solvent, preferably triethylene glycol monobutyl ether (Nanjing Gutian Chemical).

[0014] In at least one embodiment, in the composition of the maleated fatty acid and its derivatives, there are 40 - 50 parts by mass of maleated fatty acid, 40 - 50 parts by mass of maleated fatty-based imidazoline amide; and 10 - 20 parts by mass of maleated fatty acid alkanolamide. As a preference, there are 45 - 50 parts by mass of maleated fatty acid, 40 - 45 parts by mass of maleated fatty-based imidazoline amide; and 5 - 10 parts by mass of maleated fatty acid alkanolamide.

[0015] In at least one embodiment, in the composition of the maleated fatty acid and its derivatives, the volume ratio of the solvent oil to the alcohol ether-based polar solvent is 40 / 60 - 60 / 40, and more preferably 55 / 45.

[0016] In at least one embodiment, in the composition of the maleated fatty acid and its derivatives, the mass ratio of the active component to the solvent is 60 / 40 - 80 / 20, and more preferably 75 / 25.

[0017] As another aspect of the present invention, it relates to a drilling fluid, which is an oil-based drilling fluid, and the above-mentioned composition of the maleated fatty acid and its derivatives is used as an emulsifier.

[0018] In at least one embodiment, this drilling fluid further includes base oil, organophilic modified clay minerals, an aqueous phase (usually calcium chloride brine) flow pattern regulator, a polymer thickener, an alkalinity regulator, an activity controller, an organophilic modified humic acid filtration reducer, and a weighting material, etc.

[0019] In at least one embodiment, in the drilling fluid, the composition of the maleated fatty acid and its derivatives is added according to the following standard: 30 - 85 g of the composition of the maleated fatty acid and its derivatives is added to a 1 L mixture of base oil and aqueous phase. The volume ratio of the base oil to the aqueous phase can be 85 / 15 - 95 / 5. Based on a total volume of 1 L of the base oil and the aqueous phase, 25 - 50 g of organophilic modified clay mineral, 10 - 20 kg of flow pattern regulator, 10 - 15 kg of polymer thickener, 30 - 50 kg of alkalinity regulator, 50 - 70 g of organophilic modified lignite filtrate reducer. On the basis of the above composition, weighting materials are used to adjust the drilling fluid to the required density.

[0020] In at least one embodiment, in the drilling fluid, the base oil is diesel oil, mineral oil, and an environmentally friendly base oil with an ultra-low aromatic hydrocarbon content synthesized artificially. The light white oil (W1 - 110) used in some embodiments of the present invention does not mean that other base oils are excluded from the present invention.

[0021] In some embodiments of the present invention, the organophilic modified clay mineral is organophilic modified hectorite (BT42); the flow pattern regulator is polyamide-based fatty acid (coded as MOD); the alkalinity regulator is calcium hydroxide or calcium oxide; the polymer thickener is a polyolefin block polymer (coded as PRM); the high-temperature-resistant organophilic modified lignite filtrate reducer is (coded as OLG(HT)), and the weighting material is barite.

[0022] The present invention also relates to the application of the above drilling fluid in the development of oil and gas wells for deep and ultra-deep oil and gas resources.

[0023] The composition of the maleated fatty acid and its derivatives provided by the present invention as an emulsifier not only converts the main component of the conventional emulsifier from polyamide to fatty imidazoline amide and fatty alkanol amide, but also grafts maleic anhydride on the unsaturated fatty group through Diels - Alder reaction, ene reaction, etc. at high temperature to form fatty imidazoline amide and fatty alkanol amide containing multiple carboxyl groups. And it is compounded with the maleated fatty acid to form a composition of maleated fatty acid and its derivatives, which is used as an emulsifier for ultra-high temperature oil-based drilling fluid. This composition not only has a high temperature resistance ability, but also has a high wetting inversion function, can reverse the hydrophilic solid surface to be oleophilic, and is stable under ultra-high temperature conditions. The formed emulsifier composition integrates emulsification and wetting functions, has a low dosage, and remarkable performance. After heat rolling at 240 °C, the emulsification rate is 85%, the wetting rate is 94%, and the demulsification voltage of the oil-based drilling fluid is 570 V, having the effect of integrating emulsification and wetting. After the drilling fluid formula is aged at 240 °C for 16 h, the demulsification voltage is still above 570 V, and the dynamic shear force of the water-in-oil drilling fluid still remains above 4.32 Pa. Detailed Embodiments

[0024] In order to make the object, technical solutions and effects of the invention clearer, the present invention will be further described in detail in conjunction with specific embodiments. However, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to more clearly and thoroughly understand the present invention and to clearly introduce the technical idea of the present invention to those skilled in the art.

[0025] The following uses specific embodiments to elaborate on the present invention. Before elaborating on the specific embodiments of the present invention in detail, the specific materials used in the present invention are described:

[0026] Example 1 Maleated Fatty Acid

[0027] Install a three-necked flask on an automatic lifting oil bath and equip it with a thermometer and a condensation reflux device. Add tall oil fatty acid to the flask and heat it to 70°C. Add maleic anhydride in an amount of 25% by mass of the tall oil fatty acid to the flask. After adding, heat the temperature of the mixture in the flask to 220°C in stages and maintain it for about 5 - 6 minutes after reaching each designed temperature. The first heating temperature range is 70°C to 130°C; the second heating temperature range is 130°C to 160°C; the third heating temperature range is 160°C to 185°C; the fourth heating temperature range is 185°C to 205°C; the fifth heating temperature range is 205°C to 220°C. Keep the reaction temperature at 220°C for 5 h, cool it to 80 - 90°C, discharge the material and cool it to room temperature. The obtained product is maleated fatty acid.

[0028] Example 2 Maleated Fatty-based Imidazoline Amide

[0029] On an automatic lifting oil bath, install a four-necked flask, and equip it with a thermometer, a stirrer, a vacuum distillation head (connected to a water separator), and a polytetrafluoro nitrogen pipeline. Feed materials according to the ratio of the molar number of fatty acid groups in tall oil fatty acid to the molar number of diethylenetriamine of 2.1:1, with a slight excess of fatty acid. The molar number of fatty acid groups in tall oil fatty acid is determined by measuring its acid value. Add tall oil fatty acid (Shanghai Lishen Chemical Co., Ltd.) to the four-necked flask. Under the protection of nitrogen, heat it to 75±5°C, add the measured diethylenetriamine (Nanjing Gutian Chemical), and raise the temperature under stirring conditions. Stop passing nitrogen, and react at 170°C±5°C for 3.5 to 4.0 h to carry out an amidation reaction, and monitor and record the water output in the water separator; after the water output is stable, continue to raise the temperature to 240°C±5°C, and then carry out intramolecular dehydration, control the vacuum degree at 0.06 - 0.09 MPa, monitor and record the water output in the water separator, and react for 4.5 to 5.0 h. When there is no increase in water in the water separator, pass nitrogen to purge the water vapor above the liquid surface of the reaction product, then add maleic anhydride (Sinopharm Group) equal to the amount of tall oil fatty acid to the flask, and continue to react at 220°C to 240°C for 5 to 6 h. Open the vacuum pump, control the vacuum degree at 0.06 - 0.09 MPa, distill off the unreacted maleic anhydride under reduced pressure, and cool to 80 - 90°C, discharge and cool to room temperature. The obtained product is maleated fatty acid group imidazoline amide.

[0030] Example 3 Maleated fatty acid alkanolamide

[0031] On an automatic lifting oil bath, install a three-necked flask, and equip it with a thermometer and a condensation reflux device. Add tall oil fatty acid to the flask and heat it to 70°C. Add maleic anhydride in an amount of 20% by mass of the tall oil fatty acid to the flask. After adding, heat the mixture in the flask to 220°C in stages, and maintain it for about 5 - 6 min after reaching each designed temperature. The first heating temperature range is 70°C to 130°C; the second heating temperature range is 130°C to 160°C, the third heating temperature range is 160°C to 185°C; the fourth heating temperature range is 185°C to 205°C, and the fifth heating temperature range is 205°C to 220°C. Keep the reaction temperature at 220°C for 5 h. The obtained product is maleated fatty acid. Cool it to 90°C - 100°C, add monoethanolamine in an amount of 10% by mass of the tall oil fatty acid, maintain the temperature and stir for 30 min, continue to raise the temperature to 160°C±5°C, and react for 3.0 h to 3.5 h until the liquid level in the water separator remains stable for about 30 min, then terminate the reaction. Cool it to 80 - 90°C, discharge and cool to room temperature. The obtained product is maleated fatty acid alkanolamide.

[0032] A composition of maleated fatty acids and their derivatives as an emulsifier for oil-based drilling fluids (coded as HT-IMA). To illustrate the different components of the emulsifier, they are respectively denoted as HT-IMA(I), HT-IMA(II), and HT-IMA(III).

[0033] Example 4: In HT-IMA(I), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 50:45:5;

[0034] Example 5: In HT-IMA(II), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 45:45:10;

[0035] Example 6: In HT-IMA(III), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 47:45:8.

[0036] Example 7: In HT-IMA(IV), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 50:50:0.

[0037] Example 8: In HT-IMA(V), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 50:40:10.

[0038] Example 9: In HT-IMA(VI), the proportion of active components is maleated fatty acid: maleated fatty-based imidazoline amide: maleated fatty acid alkanolamide = 40:40:20.

[0039] According to the ratios in Examples 4 to 9, accurately weigh the products obtained in Examples 1 to 3.

[0040] For Examples 4 to 6, based on 100 parts by mass of the mixture, add 33 parts by mass of the mixed solvent, and the effective substance concentration is approximately 75%. Among them, the ratios of the environmental solvent oil D120 to dipropylene glycol methyl ether in the mixed solvent are 60 / 40 (Example 4), 55 / 45 (Example 5), and 40 / 60 (Example 6) respectively.

[0041] For Example 7, based on 100 parts by mass of the mixture, add 43 parts by mass of the solvent with a mixing ratio of 55 / 45, and the effective substance concentration is 70%; in Example 8, add 33 parts by mass of the solvent with a mixing ratio of 55 / 45, and the effective substance concentration is 75%; in Example 9, add 25 parts by mass of the solvent with a mixing ratio of 55 / 45, and the effective substance concentration is 80%.

[0042] Pro-organic modified clay minerals: mainly use the high-temperature resistant oil-based drilling fluid viscosity increasing agent pro-organic modified hectorite (BT42, Elementis Heimersdeqian), the main component of which is lithium saponite modified by long carbon chain quaternary ammonium salt cationic surfactant;

[0043] Alkalinity regulator: mainly use commercially available calcium hydroxide or calcium oxide;

[0044] Polymer thickener: use the oil-based drilling fluid polymer thickener polyolefin block copolymer (denoted as PRM), the main component of which is a triblock polymer of (substituted) styrene homopolymer chain segment - olefin copolymer chain segment - (substituted) styrene, and the commercial product selected is Kraton G 1701.

[0045] High-temperature resistant pro-organic modified lignite filtration reducer: use the oil-based drilling fluid filtration reducer fatty amide lignite (denoted as OLG(HT)), and select the organic lignite BLACKLIGO 500 from Shark Petroleum Technology Services Company, the main component of which is the product of fatty amide lignite modified by long-chain fatty amine.

[0046] Flow pattern regulator: mainly use the flow pattern regulator polyamide-based fatty acid MOD for oil-based drilling fluid invented by Bohai Drilling Mud Company, the main component of which is polyamide fatty acid formed by polycondensation of polyamine and mixed polybasic fatty acids (dibasic fatty acid and tribasic fatty acid), and it is prepared according to Chinese Patent 201310684666.9.

[0047] Weighting material: mainly use commercially available API barite and ultrafine manganese powder Micromax (Shanghai Aiken).

[0048] 1. Test of emulsion breaking voltage, emulsification rate and wetting rate of the composition of maleated fatty acid and its derivatives

[0049] (1) Emulsification rate

[0050] Measure 256 mL of No. 5 white oil, add 12.0 g of emulsifier, stir at high speed for 20 min, then measure 60 mL of distilled water, slowly add it to the high-speed stirring cup, and stir at high speed for 20 min. Finally, add 6.0 g of pro-organic modified hectorite and stir at high speed for 10 min to obtain a uniformly dispersed emulsion. Pour the prepared emulsion into a 500 mL graduated cylinder (accurate to 0.1 mL), let it stand at room temperature for 24 h, and observe the volume of the separated oil layer (mL). Calculate the emulsification rate according to formula (1):

[0051]

[0052] In the formula, W is the emulsification rate, %; V 总 is the total volume, %; V is the volume of the separated oil layer after 24 h, mL.

[0053] (2) Demulsification voltage

[0054] Measure 256 mL of No. 5 white oil, add 12.0 g of emulsifier, and stir at high speed for 10 min. Then measure 28 mL of 20% calcium chloride solution and slowly add it to the high-speed stirring cup, and stir at high speed for 10 min. Add 6.0 g of organophilic modified hectorite (20 g / L), stir at high speed for 10 min, and finally add 806 g (accurate to 0.01 g) of barite, stir at high speed for 40 min, and immediately measure the demulsification voltage according to the provisions in GB / T 16783.2. After the test is completed, put the test slurry into a high-temperature aging tank, fill it with 1.0 MPa of nitrogen, heat roll at the specified temperature for 16 h, cool it, stir at high speed at 11000±300 r / min for 60 min, and immediately measure the demulsification voltage according to the provisions in GB / T 16783.2.

[0055] (3) Wetting rate

[0056] Measure 150 mL of No. 5 white oil into a high-speed stirring cup, add 0.75 g of organophilic modified hectorite, stir at high speed at 11000 r / min for 20 min, and then add 1 mL (accurately measured with a glass syringe) of the sample. After stirring at high speed at 11000 r / min for 20 min, add 15.0 g (accurate to 0.01 g) of barite while stirring, stir at high speed at 11000 r / min for 20 min to make it fully dispersed and uniform. Quickly pour it into a graduated cylinder and let it stand for 90 min, and read the volume of the upper clear oil. Calculate the wetting rate according to formula (2-5). In addition, prepare the same test slurry, heat roll at the specified temperature for 16 h, stir at high speed for 30 min after aging, quickly pour it into a graduated cylinder, let it stand for 90 min, read the volume of the upper clear oil, and calculate the wetting rate according to formula (2) to investigate the temperature resistance performance of the product's wettability.

[0057]

[0058] In the formula, W is the wetting rate, %; V is the volume of the upper clear oil in the graduated cylinder, mL.

[0059] The test results are shown in Table 1.

[0060] Table 1 Evaluation results of ultra-high temperature emulsification and wetting properties of the composition of maleated fatty acids and their derivatives

[0061]

[0062]

[0063] It can be seen from the evaluation results that the emulsifiers all have good emulsifying performance and electrical stability, and can keep the stability of the demulsification voltage of the system before and after aging. Among them, the effect of Example 5 is the best. The product in Example 5 is tested in the formula, and at the same time, the high-temperature resistance ability of the oil-based drilling fluid formula is evaluated.

[0064] 2. Testing and Evaluation of Ultra-High Temperature Oil-Based Drilling Fluids Using Combinations of Maleated Fatty Acids and Their Derivatives as Emulsifiers

[0065] The preparation procedure of the high-temperature and high-density oil-based / synthetic-based drilling fluid provided by the present invention is as follows:

[0066] (1) Measure the base oil, and add the emulsifier and the flow pattern regulator respectively, and stir at 11000 ± 300 RPM (revolutions per minute) for 5 - 10 min;

[0067] (2) Measure the calcium chloride solution, and slowly add it to the above-mentioned base oil, and stir at 11000 ± 300 RPM (revolutions per minute) for 25 - 30 min;

[0068] (3) Add the alkalinity regulator and the organophilic modified clay mineral, and stir at 11000 ± 300 RPM (revolutions per minute) for 10 - 15 min;

[0069] (4) Add the polymer thickener, and stir at 11000 ± 300 RPM (revolutions per minute) for 10 - 15 min;

[0070] (5) Add the filtrate reducer and the plugging agent, and stir at 11000 ± 300 RPM (revolutions per minute) for 10 - 15 min;

[0071] (6) Add the weighting material, and stir at 11000 ± 300 RPM (revolutions per minute) for 30 - 45 min.

[0072] Example 10: 255 mL light white oil + 50 g / L emulsifier HT-IMA(II) + 15 g / L MOD + 52 mL calcium chloride (25% salt solution) + 35 g / L calcium oxide + 50 g / L BT42 + 70 g / L filtrate reducer OLG(HT) + 10 g / L PRM + 440 g barite (Grade I). The properties of the drilling fluid after high-temperature aging are shown in Table 2.

[0073] Table 2 Evaluation Results of Ultra-High Temperature Performance of Oil-Based Drilling Fluids Containing Combinations of Maleated Fatty Acids and Their Derivatives

[0074]

[0075] As can be seen from Table 2, temperature has a significant impact on the emulsion stability of water-in-oil drilling fluids. For the water-in-oil drilling fluid containing 3% compound emulsifier, after aging at 180°C - 240°C, the demulsification voltage gradually decreases. After high-temperature aging at 240°C for 16 h, the demulsification voltage is still as high as 576 V, and the yield point of the water-in-oil drilling fluid remains at 4.32 Pa, indicating that the maximum applicable temperature of the compound emulsifier is 240°C.

[0076] 3. Ultra-high temperature and high-density oil-based drilling fluids containing maleated fatty acids and their derivatives

[0077] Example 8: 180 mL light white oil + 40 g / L HT-IMA (II) + 5 g / L MOD + 23 mL CaCl2 (25%) + 30 g / L CaO + 20 g / L BT42 + 80 g / L OLG (HT) + 5 g / L PRM 800 g barite (drilling fluid density weighted to 2.5 g / cm 3 )

[0078] Example 9: 190 mL light white oil + 40 g / L HT-IMA (II) + 5 g / L MOD + 11.5 mL CaCl2 (25%) + 30 g / L CaO + 20 g / L BT42 + 80 g / L OLG (HT) + 8 g / L PRM 800 g barite (drilling fluid density weighted to 2.5 g / cm 3 )

[0079] The test results of the drilling fluid properties in Example 8 and Example 9 are shown in Table 3.

[0080] Table 3 Performance evaluation results of ultra-high temperature and high-density oil-based drilling fluids

[0081]

[0082] 4. Ultra-high temperature and high-density oil-based drilling fluids containing maleated fatty acids and their derivatives

[0083] Increase the dosage of the emulsifier in Example 5 to 60 g / L. After aging the prepared drilling fluid, contaminate the above drilling fluid with 40% fresh water, 40% compound brine (200 g / L sodium chloride + 100 g / L calcium chloride), 5% shale powder (≤100 mesh), and 5% calcium sulfate respectively, and test the properties of the contaminated drilling fluid after hot rolling at 180°C for 16 h. The results are shown in Table 4.

[0084] Table 4 Test and evaluation results of the anti-contamination performance of ultra-high temperature and high-density oil-based drilling fluids

[0085]

[0086] After being contaminated by 40% fresh water and compound brine, the ultra-high temperature and high-density oil-based drilling fluid has a significantly reduced oil-water ratio. After being exposed to a high temperature of 180°C and contaminated by a high-pressure water layer in deep high-temperature formations, there has been no over-thickening phenomenon, and it maintains good rheology. The demulsification voltage is greater than 350V. At the same time, when contaminated by 5.0% shale and calcium sulfate, after the drilling fluid is thermally rolled at 180°C, it maintains good rheology and filtration plugging performance, and the demulsification voltage is above 1200V. Under high-proportion contamination conditions, the ultra-high temperature and high-density drilling fluid formed can still maintain good electrical stability, rheology and filtration plugging performance, and can effectively cope with extremely thick shale formations, gypsum salt formations and high-pressure water layers.

[0087] For the present invention, it should be further noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than being restrictive. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the technical idea and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A composition of maleated fatty acids and their derivatives, characterized in that, Using maleated fatty acids, maleated fatty-based imidazoline amides, and maleated fatty acid alkanolamides as active components, and a mixture of solvent oil and alcohol ether as the solvent, the mass ratio of the active components to the solvent is 60 / 40 to 80 / 20; wherein, among the active components, there are 45 to 50 parts by mass of maleated fatty acids, 40 to 45 parts by mass of maleated fatty-based imidazoline amides, and 5 to 10 parts by mass of maleated fatty acid alkanolamides; the volume ratio of the solvent oil to the alcohol ether is 40 / 60 to 60 / 40; and the alcohol ether is a polyol ether-based polar solvent.

2. The composition of the maleated fatty acid and its derivatives according to claim 1, characterized in that, The maleated fatty acids are formed by reacting natural plant fatty acids rich in unsaturated bonds with maleic anhydride under high temperature or catalytic conditions.

3. The composition of the maleated fatty acid and its derivatives according to claim 1, characterized in that, The maleated fatty-based imidazoline amides are maleated fatty-based imidazoline amides formed by reacting natural plant fatty acids rich in unsaturated bonds with diethylenetriamine, through intermolecular dehydration amidation, intramolecular dehydration to form a ring under high temperature or catalytic conditions, and then reacting with maleic anhydride under high temperature or catalytic conditions.

4. The composition of the maleated fatty acid and its derivatives according to claim 1, characterized in that The maleated fatty acid alkanolamides are obtained by reacting maleated fatty acids formed by reacting natural plant fatty acids rich in unsaturated bonds with maleic anhydride under catalytic conditions, and then reacting with hydroxyethyl mono-substituted or di-substituted organic amines.

5. The composition of the maleated fatty acid and its derivatives according to claim 1, characterized in that, The solvent oil is a de-aromatic solvent oil mainly composed of alkanes and cycloalkanes.

6. A drilling fluid, characterized in that, The drilling fluid is an oil-based drilling fluid, and a composition of the maleated fatty acids and their derivatives according to any one of claims 1-5 is used as an emulsifier.

7. The drilling fluid according to claim 6, characterized in that, The drilling fluid further includes base oil, organophilic modified clay minerals, aqueous phase flow pattern regulator, polymer thickener, alkalinity regulator, activity control agent, organophilic modified humic acid filtrate reducer, and weighting material.

8. The drilling fluid according to claim 7, characterized in that, The composition of the maleated fatty acids and their derivatives is added according to the following standard: 30-85 g of the composition of the maleated fatty acids and their derivatives is added to a 1L mixture of base oil and aqueous phase.

9. The drilling fluid according to claim 8, wherein The volume ratio of base oil to aqueous phase is 85 / 15 to 95 / 5. Based on a total volume of 1L of base oil and aqueous phase, there are 20-50 g of organophilic modified clay minerals, 10-20 g of flow pattern regulator, 5-10 g of polymer thickener, 30-50 g of alkalinity regulator, and 70-80 g of organophilic modified lignite filtrate reducer.

10. The drilling fluid according to claim 7, characterized in that, The base oil is diesel oil, mineral oil, and an environmentally friendly base oil with ultra-low aromatic hydrocarbon content synthesized artificially.

11. The drilling fluid according to claim 7, characterized in that, The organophilic modified clay minerals are organophilic modified hectorite; the flow pattern regulator is polyamide-based fatty acid; the alkalinity regulator is calcium hydroxide or calcium oxide; the polymer thickener is a polyolefin block polymer; the filtrate reducer is high-temperature resistant organophilic modified lignite, and the weighting material is barite.

12. Application of the drilling fluid according to any one of claims 6-11 in the exploration and development of deep and ultra-deep oil and gas resources.

Images