Emulsifier for oil-based drilling fluid as well as preparation method and application of emulsifier

Abstract

The invention provides an emulsifier for an oil-based drilling fluid as well as a preparation method and application of the emulsifier. The emulsifier for the oil-based drilling fluid is prepared from the following raw materials: a first compound, a second compound, a third compound and a fourth compound, the first compound comprises a modified inorganic filler; the molecular structure of the modified inorganic filler contains amino groups; the second compound comprises a long-chain unsaturated acid compound; the third compound comprises a compound containing a hydroxyl group and an amino group, and / or a compound containing a carboxyl group and an amino group; the fourth compound comprises a propylene diamine compound. In the invention, the emulsifier for the oil-based drilling fluid can keep good emulsification stability in a high-temperature environment of a deep layer and an ultra-deep layer, so that the rheological stability and sedimentation stability of a system are effectively maintained, and the purpose of controlling filtration loss is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil-based drilling fluid for petroleum drilling, and specifically relates to an emulsifier for oil-based drilling fluid and a preparation method and application thereof. Background Art

[0002] With the continuous development of conventional oil and gas resources, the contradiction between people's growing energy demand and oil and gas production is deepening. The discovery of deep and ultra-deep large-scale oil and gas reservoirs in recent years has continuously improved the energy status of deep and ultra-deep layers, making them an important successor energy source in my country. The drilling technology of deep and ultra-deep layers is still in the development stage, especially the oil-based drilling fluid technology. In deep and ultra-deep layers, there will be complex geological environments such as high temperature, high pressure, extremely thick salt gypsum layers and high-pressure brine layers, which poses a greater challenge to the stability of oil-based drilling fluids, especially the stability of emulsions.

[0003] At present, the commonly used oil-based drilling fluid emulsifiers generally have the problem of insufficient temperature resistance. When the temperature is higher than 220℃, the oil-in-water emulsion will break due to the high-temperature decomposition of the emulsifier, making it difficult to maintain the stability of the entire oil-in-water emulsion, which can easily cause emulsification instability, rheological deterioration, increased material sedimentation, and difficulty in controlling filtration, further causing complex downhole problems such as well wall instability, drilling obstruction, and drilling jamming. Therefore, the research on oil-based drilling fluid emulsifiers with high temperature resistance has far-reaching significance for the development of deep and ultra-deep well oil-based drilling fluid technology and the development of deep and ultra-deep oil and gas.

[0004] For example, CN115197678A discloses a drilling fluid emulsifier and a preparation method thereof, which is obtained by mixing water, a base agent, and modified barite and then homogenizing at high speed. The stability of the emulsifier is improved; however, its high temperature resistance still needs to be further improved.

[0005] CN109097005A discloses an oil-based drilling fluid emulsifier, comprising the following components: 8 to 15 parts of stearic acid monoglyceride, 80 to 100 parts of water, 30 to 60 parts of emulsifier base, 10 to 15 parts of nano additives and 10 to 15 parts of salt-resistant and temperature-resistant additives; however, the emulsification efficiency of the emulsifier is low, and the high temperature resistance performance needs to be further improved.

[0006] Therefore, developing an emulsifier with high emulsification efficiency, high high temperature resistance and good stability is an urgent problem to be solved in the field. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide an emulsifier for oil-based drilling fluid and a preparation method and application thereof. The emulsifier for oil-based drilling fluid can maintain good emulsification stability in a high temperature environment of deep and ultra-deep layers, thereby effectively maintaining the rheological stability and sedimentation stability of the system and achieving the purpose of controlling filtration loss.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier for oil-based drilling fluid include a first compound, a second compound, a third compound and a fourth compound; the first compound includes a modified inorganic filler; the modified inorganic filler contains an amino group in its molecular structure; the second compound includes a long-chain unsaturated acid compound; the third compound includes a compound containing a hydroxyl group and an amino group, and / or a compound containing a carboxyl group and an amino group; the fourth compound includes a propylene diamine compound.

[0010] In the present invention, specific raw materials are selected and inorganic materials are combined with organic materials so that the emulsifier can still effectively improve the emulsification stability of the oil-based drilling fluid under an extremely high temperature environment of 260°C, effectively solve the emulsion demulsification problem of the oil-based drilling fluid system under ultra-high temperature conditions, and at the same time improve the rheological stability of the system, reduce filtration loss, and meet the actual drilling needs of deep wells and ultra-deep wells at this stage.

[0011] Preferably, the modified inorganic filler includes at least one of modified silica, modified titania or modified alumina.

[0012] Preferably, the modifier in the modified inorganic filler includes an amino-containing silane coupling agent.

[0013] Preferably, the amino-containing silane coupling agent includes at least one of aminopropyltriethoxysilane, aminopropyltrimethoxysilane, anilinomethyltriethoxysilane, anilinomethyltrimethoxysilane, aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane or N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0014] Preferably, the molar amount of the inorganic filler in the modified inorganic filler is 1 mol, and the molar amount of the modifier is 0.5-2.5 mol, for example, it can be 0.5 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1 mol, 1.1 mol, 1.2 mol, 1.3 mol, 1.4 mol, 1.5 mol, 1.6 mol, 1.7 mol, 1.8 mol, 1.9 mol, 2 mol, 2.1 mol, 2.2 mol, 2.3 mol, 2.4 mol, 2.5 mol, etc.; preferably, it is 0.75-2.5 mol, and more preferably, it is 1-2.5 mol.

[0015] Preferably, the particle size of the inorganic filler is 10 to 50 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0016] Preferably, the long-chain unsaturated acid compounds include C12-C22 unsaturated fatty acids, for example, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22 unsaturated fatty acids, etc.

[0017] Preferably, the long-chain unsaturated acid compound includes at least one of vegetable oleic acid, linolenic acid, linoleic acid, myristic acid, palmitoleic acid or rapeseed oleic acid.

[0018] Preferably, the molar amount of the inorganic filler in the modified inorganic filler is 1 mol, and the molar amount of the second compound is 1 to 5 mol, for example, it can be 1 mol, 1.2 mol, 1.4 mol, 1.5 mol, 1.6 mol, 1.8 mol, 2 mol, 2.2 mol, 2.5 mol, 2.6 mol, 2.8 mol, 3 mol, 3.2 mol, 3.4 mol, 3.6 mol, 3.8 mol, 4 mol, 4.2 mol, 4.4 mol, 4.6 mol, 4.8 mol, 5 mol, etc.; preferably 1.5 to 5 mol, and more preferably 2 to 5 mol.

[0019] Preferably, the third compound includes at least one of hydroxyethylethylenediamine, N-(2-hydroxypropyl)ethylenediamine or ethylenediaminetetraacetic acid.

[0020] Preferably, taking the molar amount of the inorganic filler in the modified inorganic filler as 1 mol, the molar amount of the third compound is 0.5-1.5 mol, for example, it can be 0.5 mol, 0.55 mol, 0.6 mol, 0.65 mol, 0.7 mol, 0.75 mol, 0.8 mol, 0.85 mol, 0.9 mol, 0.95 mol, 1 mol, 1.05 mol, 1.1 mol, 1.15 mol, 1.2 mol, 1.25 mol, 1.3 mol, 1.35 mol, 1.4 mol, 1.45 mol, 1.5 mol, etc.; preferably, it is 0.6-1.5 mol, and more preferably, it is 0.75-1.5 mol.

[0021] Preferably, the fourth compound includes at least one of trimethylene diamine, tallow-1,3 trimethylene diamine, N-oleyl-1,3 trimethylene diamine or N-stearyl-1,3 trimethylene diamine.

[0022] Preferably, taking the molar amount of the inorganic filler in the modified inorganic filler as 1 mol, the molar amount of the fourth compound is 1 to 5 mol, for example, it can be 1 mol, 1.2 mol, 1.4 mol, 1.5 mol, 1.6 mol, 1.8 mol, 2 mol, 2.2 mol, 2.5 mol, 2.6 mol, 2.8 mol, 3 mol, 3.2 mol, 3.4 mol, 3.6 mol, 3.8 mol, 4 mol, 4.2 mol, 4.4 mol, 4.6 mol, 4.8 mol, 5 mol, etc.; preferably 1.5 to 5 mol, more preferably 2 to 5 mol.

[0023] In a second aspect, the present invention provides a method for preparing the emulsifier for oil-based drilling fluid according to the first aspect, the preparation method comprising the following steps:

[0024] The first compound, the second compound, the third compound and the fourth compound are reacted to obtain the oil-based drilling fluid emulsifier.

[0025] Preferably, the reaction includes: mixing the first compound with the second compound and the third compound to perform a first contact reaction to obtain a first intermediate; performing a second contact reaction on the first intermediate with a fourth compound having a formula amount of 40 to 50% (for example, 40%, 42%, 44%, 46%, 48%, 50%, etc.) to obtain a second intermediate; performing a third contact reaction on the second intermediate with the remaining fourth compound to obtain the emulsifier for oil-based drilling fluid.

[0026] Preferably, the temperature of the first contact reaction is 45-95°C, for example, it can be 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, etc.; the time is 0.5-2.5h, for example, it can be 0.5h, 0.8h, 1h, 1.2h, 1.5h, 2h, 2.2h, 2.5h, etc.; more preferably, the temperature is 50-65°C, and the time is 1-2h.

[0027] Preferably, the temperature of the second contact reaction is 120-190°C, for example, it can be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, etc.; the time is 4-12h, for example, it can be 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc.; more preferably, the temperature is 150-170°C and the time is 6-8h.

[0028] Preferably, the temperature of the third contact reaction is 60-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, etc.; the time is 1-5h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, etc.; more preferably, the temperature is 70-90°C, and the time is 2-4h.

[0029] Preferably, the first contact reaction, the second contact reaction and the third contact reaction are each independently carried out under negative pressure conditions.

[0030] In the present invention, the reaction is carried out under negative pressure, which is conducive to the reaction proceeding in the positive direction and improves the yield of the reaction product.

[0031] Preferably, the preparation method of the first compound comprises:

[0032] The modifier, the inorganic filler and the solvent are mixed and reacted to obtain the first compound.

[0033] Preferably, the reaction is carried out under alkaline conditions.

[0034] In the present invention, the alkaline material used in the alkaline condition includes but is not limited to one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate or ammonia water.

[0035] Preferably, the reaction temperature is 40-95°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, etc.; the reaction time is 0.5-4h, for example, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, etc.; more preferably, the reaction temperature is 50-70°C, and the reaction time is 1-3h.

[0036] Preferably, the solvent comprises an alcohol-water mixed solution.

[0037] In the present invention, the alcohol includes but is not limited to one or more of methanol, ethanol, n-propanol, and isopropanol; the alcohol-water mixed solution is used to ensure the full dispersion of the inorganic nanomaterial, and at the same time promote the full hydrolysis of the silane coupling agent, which is conducive to the grafting reaction between the silane coupling agent and the nano inorganic material.

[0038] In the present invention, the speed of mixing the modifier, inorganic filler and solvent is 350-450rpm, for example, 350rpm, 360rpm, 380rpm, 400rpm, 420rpm, 440rpm, 450rpm, etc.; mixing at a specific speed can achieve a more complete reaction.

[0039] As a preferred technical solution of the present invention, the preparation method comprises:

[0040] (1) mixing a modifier, an inorganic filler and a solvent, and reacting them under alkaline conditions at a temperature of 40 to 95° C. for 0.5 to 4 hours to obtain the first compound;

[0041] (2) mixing the first compound with the second compound and the third compound, and reacting them at 45 to 95° C. for 0.5 to 2.5 hours to obtain a first intermediate;

[0042] (3) reacting the first intermediate with 40-50% of the fourth compound at 120-190° C. for 4-12 hours to obtain a second intermediate;

[0043] (4) reacting the second intermediate with the remaining fourth compound at 60-100° C. for 1-5 hours to obtain the oil-based drilling fluid emulsifier.

[0044] In the present invention, the preparation method comprises the following steps: firstly, under alkaline conditions, a silane coupling agent is used in an alcohol aqueous solution to modify a nano inorganic filler so that the surface of the inorganic nano material has an amino group, and then the nano inorganic filler is reacted with an unsaturated acid, and then a third compound and a part of a propylene diamine compound are added to carry out an amidation reaction, and finally, the propylene diamine compound is reacted fully to remove the amide fat, so as to obtain an emulsifier with a specific structure, which is beneficial to improving the temperature resistance and emulsification performance of the emulsifier.

[0045] In a third aspect, the present invention provides an oil-based drilling fluid, wherein the oil-based drilling fluid comprises the emulsifier for oil-based drilling fluid as described in the first aspect.

[0046] Preferably, the mass percentage of the emulsifier in the oil-based drilling fluid is 4-6%, for example, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, 5.2%, 5.4%, 5.6%, 5.8%, 6%, etc.

[0047] In the present invention, the oil-based drilling fluid also includes an oil phase and an aqueous phase; the oil phase may be, for example, diesel or white oil, and the white oil is preferably 3# white oil (flash point of 220°C, kinematic viscosity of 3mm at 40°C). 2 / s, specific gravity is 0.85) or 5# white oil (flash point is 220℃, kinematic viscosity at 40℃ is 3.5mm 2 / s, specific gravity is 0.85); the aqueous phase includes but is not limited to CaCl 2 An aqueous solution, preferably a CaCl solution having a mass concentration of 20 to 40% (e.g., 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, etc.) 2 wherein the volume ratio of the oil phase to the water phase is 70-90:30-10.

[0048] In the present invention, the oil-based drilling fluid also includes other treatment agents, including but not limited to one or more of rheology regulators, wetting agents, alkalinity regulators or weighting agents; the above-mentioned treatment agents and their amounts can be selected with reference to the conventional types and amounts in the art, and the present invention has no special limitation on this.

[0049] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The emulsifier for oil-based drilling fluid provided by the present invention selects specific compound raw materials with specific groups, combines inorganic materials with organic materials, so that the emulsifier can effectively improve the emulsification stability of the oil-based drilling fluid under an extremely high temperature environment of 260°C, and has high emulsification efficiency under normal high temperature; it effectively solves the emulsion demulsification problem of the oil-based drilling fluid system under ultra-high temperature conditions, and at the same time can improve the rheological stability of the system, reduce filtration loss, and meet the actual drilling needs of deep wells and ultra-deep wells at this stage. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0053] In the following examples, unless otherwise stated, all chemical reagents used are commercially available. Among them, nano-silicon dioxide was purchased from Nanjing Xianfeng Nanomaterial Technology Co., Ltd., and ammonia, aminopropyl triethoxysilane, tallow 1,3-propylene diamine, and N-(2-hydroxypropyl)ethylenediamine were purchased from San Chemical Technology (Shanghai) Co., Ltd.

[0054] Example 1

[0055] The present embodiment provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier include 28.5 g of modified nano-silica (including 6.4 g of nano-silica and 22.1 g of aminopropyltriethoxysilane), 56.4 g of vegetable oleic acid, 8.85 g of N-(2-hydroxypropyl)ethylenediamine, and 40.8 g of tallow 1,3-propylene diamine; the molar ratio of the nano-silica, aminopropyltriethoxysilane, vegetable oleic acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylene diamine is 1:1:2:0.75:2.

[0056] This embodiment provides a method for preparing an emulsifier for oil-based drilling fluid, comprising:

[0057] (1) preparing an ethanol-water mixed solution in a ratio of 6:4 by volume of ethanol to deionized water, dispersing 6.4 g of nano-silica in 100 mL of the mixed solution, adding a certain amount of ammonia water to adjust the pH value of the solution to 9, raising the temperature to 50° C., and then adding 22.1 g of aminopropyltriethoxysilane dropwise, and continuing the reaction for 2 h to obtain modified nano-silica;

[0058] (2) Add 56.4 g of vegetable oleic acid and 8.85 g of N-(2-hydroxypropyl)ethylenediamine to the modified nano-silica obtained in step (1), raise the temperature to 55° C., continue to react for 1 hour, then continue to add 20.4 g of tallow 1,3-propylene diamine, raise the temperature to 150° C., react for 6 hours, then lower the temperature to 90° C., continue to add 20.4 g of tallow 1,3-propylene diamine, react for 2 hours, and obtain the oil-based drilling fluid emulsifier.

[0059] Example 2

[0060] The present embodiment provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier include 32.92 g of modified nano-silica (including 6.4 g of nano-silica and 26.52 g of aminopropyltriethoxysilane), 70.5 g of vegetable oleic acid, 10.62 g of N-(2-hydroxypropyl)ethylenediamine, and 49 g of tallow 1,3-propylene diamine; the molar ratio of the nano-silica, aminopropyltriethoxysilane, vegetable oleic acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylene diamine is 1:1.2:2.5:0.9:2.4.

[0061] This embodiment provides a method for preparing an emulsifier for oil-based drilling fluid, comprising:

[0062] (1) preparing an ethanol-water mixed solution in a ratio of 6:4 by volume of ethanol to deionized water, then dispersing nano-silica in 100 mL of the mixed solution, adding a certain amount of ammonia water to adjust the pH value of the solution to 9, raising the temperature to 55° C., and then adding aminopropyltriethoxysilane dropwise, and continuing the reaction for 2 h to obtain modified nano-silica;

[0063] (2) Add vegetable oleic acid and N-(2-hydroxypropyl)ethylenediamine to the modified nano-silica obtained in step (1), raise the temperature to 60° C., continue to react for 1.5 hours, then continue to add 50% of the formula amount of tallow ester 1,3-propylene diamine, raise the temperature to 155° C., react for 6 hours, then lower the temperature to 90° C., continue to add the remaining tallow ester 1,3-propylene diamine, and react for 2.5 hours to obtain the oil-based drilling fluid emulsifier.

[0064] Example 3

[0065] The present embodiment provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier include 39.55 g of modified nano-silica (including 6.4 g of nano-silica and 33.15 g of aminopropyltriethoxysilane), 84.6 g of vegetable oleic acid, 11.8 g of N-(2-hydroxypropyl)ethylenediamine, and 61.2 g of tallow 1,3-propylene diamine; the molar ratio of the nano-silica, aminopropyltriethoxysilane, vegetable oleic acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylene diamine is 1:1.5:3:1:3.

[0066] This embodiment provides a method for preparing an emulsifier for oil-based drilling fluid, comprising:

[0067] (1) preparing an ethanol-water mixed solution in a ratio of 7:3 by volume of ethanol to deionized water, then dispersing nano-silica in 100 mL of the mixed solution, adding a certain amount of ammonia water to adjust the pH value of the solution to 10, raising the temperature to 65° C., and then adding aminopropyltriethoxysilane dropwise, and continuing the reaction for 2 h to obtain modified nano-silica;

[0068] (2) Add vegetable oleic acid and N-(2-hydroxypropyl)ethylenediamine to the modified nano-silica obtained in step (1), raise the temperature to 85° C., continue to react for 2 hours, then continue to add 50% of the formula amount of tallow 1,3-propylene diamine, raise the temperature to 160° C., react for 4 hours, then lower the temperature to 90° C., continue to add the remaining tallow 1,3-propylene diamine, and react for 4 hours to obtain the oil-based drilling fluid emulsifier.

[0069] Example 4

[0070] The present embodiment provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier include 39.55 g of modified nano-silica (including 6.4 g of nano-silica and 38.67 g of aminopropyltriethoxysilane), 98.7 g of vegetable oleic acid, 12.98 g of N-(2-hydroxypropyl)ethylenediamine, and 71.4 g of tallow 1,3-propylene diamine; the molar ratio of the nano-silica, aminopropyltriethoxysilane, vegetable oleic acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylene diamine is 1:1.75:3.5:1.1:3.5.

[0071] This embodiment provides a method for preparing an emulsifier for oil-based drilling fluid, comprising:

[0072] (1) preparing an ethanol-water mixed solution in a ratio of 7:3 by volume of ethanol to deionized water, then dispersing nano-silica in 100 mL of the mixed solution, adding a certain amount of ammonia water to adjust the pH value of the solution to 10, raising the temperature to 70° C., and then adding aminopropyltriethoxysilane dropwise, and continuing the reaction for 2.5 hours to obtain modified nano-silica;

[0073] (2) Add vegetable oleic acid and N-(2-hydroxypropyl)ethylenediamine to the modified nano-silica obtained in step (1), raise the temperature to 85° C., continue to react for 2 hours, continue to add 50% of the formula amount of tallow ester 1,3-propylene diamine, raise the temperature to 165° C., react for 6 hours, then lower the temperature to 80° C., continue to add the remaining tallow ester 1,3-propylene diamine, react for 3 hours, and obtain the oil-based drilling fluid emulsifier.

[0074] Example 5

[0075] The present embodiment provides an emulsifier for oil-based drilling fluid, wherein the raw materials for preparing the emulsifier include 50.6 g of modified nano-silica (including 6.4 g of nano-silica and 44.2 g of aminopropyltriethoxysilane), 112.8 g of vegetable oleic acid, 14.75 g of N-(2-hydroxypropyl)ethylenediamine, and 81.6 g of tallow 1,3-propylene diamine; the molar ratio of the nano-silica, aminopropyltriethoxysilane, vegetable oleic acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylene diamine is 1:2:4:1.2:4.

[0076] This embodiment provides a method for preparing an emulsifier for oil-based drilling fluid, comprising:

[0077] (1) preparing an ethanol-water mixed solution in a ratio of 7:3 by volume of ethanol to deionized water, then dispersing nano-silica in 100 mL of the mixed solution, adding a certain amount of ammonia water to adjust the pH value of the solution to 10, raising the temperature to 70° C., and then adding aminopropyltriethoxysilane dropwise, and continuing the reaction for 3 hours to obtain modified nano-silica;

[0078] (2) Add vegetable oleic acid and N-(2-hydroxypropyl)ethylenediamine to the modified nano-silica obtained in step (1), raise the temperature to 85° C., continue to react for 2 hours, then continue to add 50% of the formula amount of tallow 1,3-propylene diamine, raise the temperature to 170° C., react for 8 hours, then lower the temperature to 70° C., continue to add the remaining tallow 1,3-propylene diamine, react for 3 hours, and obtain the drilling fluid emulsifier.

[0079] Example 6

[0080] The present embodiment provides an emulsifier for drilling fluid, and the preparation raw materials include modified nano titanium dioxide (including nano titanium dioxide and aminopropyl trimethoxysilane), myristic acid, hydroxyethyl ethylenediamine, and N-stearyl-1,3-propylene diamine; the molar amount of nano titanium dioxide is the same as the molar amount of nano silicon dioxide in Example 1, and the amounts of other components are adjusted so that the molar ratio of nano titanium dioxide, aminopropyl trimethoxysilane, myristic acid, hydroxyethyl ethylenediamine and N-stearyl-1,3-propylene diamine is 1:0.75:1.5:0.6:1.5.

[0081] This embodiment provides a method for preparing an emulsifier for drilling fluid, and the specific steps are the same as those in Embodiment 1.

[0082] Example 7

[0083] The present embodiment provides an emulsifier for drilling fluid, and the preparation raw materials include modified nano alumina (including nano alumina and N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane), linoleic acid, ethylenediaminetetraacetic acid, and N-oleyl-1,3-propylene diamine; the molar amount of nano alumina is the same as the molar amount of nano silicon dioxide in Example 1, and the amounts of other components are adjusted so that the molar ratio of nano alumina, N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane, linoleic acid, ethylenediaminetetraacetic acid and N-oleyl-1,3-propylene diamine is 1:2.5:5:1.5:5.

[0084] This embodiment provides a method for preparing an emulsifier for drilling fluid, and the specific steps are the same as those in Embodiment 1.

[0085] Example 8

[0086] This embodiment provides an emulsifier for drilling fluid, which is different from Example 1 only in that the amount of the nano-silicon dioxide is unchanged, and the amounts of other components are adjusted so that the molar ratio of the nano-silicon dioxide, aminopropyltriethoxysilane, vegetable oil acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylenediamine is 1:0.2:0.5:0.2:0.5, and the rest is the same as Example 1.

[0087] Example 9

[0088] This embodiment provides an emulsifier for drilling fluid, which is different from Example 1 only in that the amount of the nano-silicon dioxide is unchanged, and the amounts of other components are adjusted so that the molar ratio of the nano-silicon dioxide, aminopropyltriethoxysilane, vegetable oil acid, N-(2-hydroxypropyl)ethylenediamine and tallow 1,3-propylenediamine is 1:3:6:2.5:6, and the rest is the same as Example 1.

[0089] Example 10

[0090] This embodiment provides an emulsifier for drilling fluid, which differs from Embodiment 1 only in that, in the preparation method, in step (2), the step of lowering the temperature to 90° C. and continuing to add tallow ester 1,3-propylene diamine for reaction is not performed, and other raw materials, amounts and step parameters are the same as those in Embodiment 1.

[0091] Embodiment 11

[0092] This embodiment provides an emulsifier for drilling fluid, which differs from Embodiment 1 only in that, in the preparation method, in step (2), the total amount of tallow ester 1,3-propylene diamine remains unchanged, and the step of lowering the temperature to 90° C. and continuing to add tallow ester 1,3-propylene diamine to react is not performed. Other raw materials, amounts and step parameters are the same as those in Embodiment 1.

[0093] Comparative Example 1

[0094] This comparative example provides an emulsifier for drilling fluid, which is different from Example 1 only in that there is no modified nano-silicon dioxide in the preparation raw materials, and other raw materials, amounts and step parameters are the same as those in Example 1.

[0095] Comparative Example 2

[0096] This comparative example provides an emulsifier for drilling fluid, which is different from Example 1 only in that there is no N-(2-hydroxypropyl)ethylenediamine in the preparation raw materials, and other raw materials, amounts and step parameters are the same as those in Example 1.

[0097] Comparative Example 3

[0098] This comparative example provides an emulsifier for drilling fluid, which differs from Example 1 only in that N-(2-hydroxypropyl)ethylenediamine is replaced by an equimolar amount of malonic acid, and other raw materials, amounts and step parameters are the same as those in Example 1.

[0099] Comparative Example 4

[0100] This comparative example provides an emulsifier for drilling fluid, which is commercially available Span-80.

[0101] Test Example 1

[0102] The emulsification effect of the emulsifiers provided in Examples 1 to 11 and Comparative Examples 1 to 4 in the water-in-oil emulsion was tested, and the specific steps included:

[0103] The emulsifiers provided in Examples 1 to 11 and Comparative Examples 1 to 4 were added to the water-in-oil emulsions, and the emulsification efficiency of the emulsions was tested at room temperature (before aging) and after high temperature aging (260°C) and after standing for 24 hours. The basic formula of the water-in-oil emulsion used is as follows: 240 mL base oil + 4% high temperature resistant emulsifier + 2% organic soil + 60 mL 20% CaCl 2The emulsification efficiency is calculated by observing the oil content of the emulsion and calculating the corresponding emulsification rate R.

[0104] R=1-V 析出油 / V 总

[0105] R is the emulsification efficiency of the emulsion, %; V 析出油 V is the volume of precipitated oil, mL; 总 is the total volume of the oil-water emulsion, mL.

[0106] The test results are shown in Table 1.

[0107] Test Example 2

[0108] The test includes the oil-in-water emulsions of the emulsifiers provided in Examples 1 to 11 and Comparative Examples 1 to 4. The demulsification voltage (ES) after high temperature aging (260° C.) and standing for 24 hours is the same. The formula of the oil-in-water emulsion is the same as that of Test Example 1. The results are shown in Table 2.

[0109] Test Example 3

[0110] The tests included the room temperature performance (before aging) and high temperature aging resistance (after aging at 260° C. for 16 hours) of oil-based drilling fluids of different densities provided by the emulsifiers provided in Examples 1 to 11 and Comparative Examples 1 to 4.

[0111] The basic formula of the oil-based drilling fluid used (oil-water ratio 90:10, density 1.6g / cm 3 and 2.6 g / cm 3 The composition of the two kinds of materials is as follows, wherein the density is 1.6 g / cm 3 Oil-based drilling fluid: 270mL base oil + 30mL CaCl 2 Aqueous solution (concentration 25wt%) + 12g high temperature resistant emulsifier + 9g organic soil + 15g CaO powder + 5% fluid loss reducer + barite (added according to different density requirements); density is 2.6g / cm 3 Oil-based drilling fluid: 270mL base oil + 30mL CaCl 2 Aqueous solution (concentration 25wt%) + 18g high temperature resistant emulsifier + 6g organic soil + 15g CaO powder + 5% fluid loss reducer + barite (added according to different density requirements); the base oil is 3# white oil purchased from Guangdong Maoming Petrochemical Company, and the organic soil, fluid loss reducer and barite are all taken from China National Petroleum Corporation Engineering Technology Research Institute Co., Ltd.

[0112] The prepared oil-based drilling fluid is placed in an aging tank, aged at 260°C for 16 hours, cooled to room temperature, and then opened to detect the sedimentation of the drilling fluid with a glass rod. Among them: hard sedimentation refers to the serious sedimentation of barite, which causes the free-falling glass rod to be unable to touch the bottom of the aging tank; soft sedimentation refers to the density difference of the drilling fluid in the aging tank, the barite sedimentation is weak, and the glass rod can slowly touch the bottom of the aging tank; no sedimentation refers to the absence of density difference between the upper and lower drilling fluids in the tank after aging. Then the drilling fluid in the aging tank is stirred at high speed at 11000rpm for 20min, and then the ZNN-D6 six-speed rotary viscometer is used to test the scale readings of 600 rpm (Φ6), 300 rpm (Φ3), 6 rpm, and 3 rpm at 65°C, and the rheological parameters of the drilling fluid are calculated according to the following formula:

[0113] Apparent viscosity: AV = 1 / 2 × 600r / min (reading) mPa.s

[0114] Plastic viscosity: PV = 600r / min (reading) - 300r / min (reading) mPa.s

[0115] Dynamic shear force: YP = 1 / 2 × (300r / min (reading) – PV) Pa.

[0116] High temperature and high pressure fluid loss reduction: FL HTHP .

[0117] Density: 1.6 g / cm 3 The drilling fluid test results are shown in Table 3; the density is 2.6 g / cm 3 The drilling fluid test results are shown in Table 4.

[0118] Among them, “ / ” and “-” mean that no test is required or the test is meaningless.

[0119] Table 1

[0120]

[0121]

[0122] As can be seen from Table 1, the emulsifier provided by the present invention adopts specific raw materials and structural design, so that the emulsifier has a high emulsification efficiency under both normal temperature and high temperature conditions; wherein the emulsifiers synthesized in Examples 1-5 and Example 7 can achieve an emulsification efficiency of 100% at room temperature, and an emulsification efficiency of 92% or more under high temperature conditions; the amount of the second compound, the third compound and the fourth compound in the raw materials of the emulsifiers synthesized in Examples 6 and 8 is small, so that the emulsification efficiency of the emulsifier after high temperature is low; the amount of the second compound, the third compound and the fourth compound used in the emulsifier synthesized in Example 9 is too much, and the effective content of the synthesized emulsifier is small, which also makes the emulsification efficiency after high temperature low; the amount of the fourth compound of the emulsifier synthesized in Example 10 is small, so that the emulsification efficiency after high temperature is low; the fourth compound of the emulsifier synthesized in Example 11 is not added in steps, resulting in a low final high temperature resistant emulsifier product, so that the emulsification efficiency after high temperature is relatively low, but the emulsification efficiency of the above emulsifiers after high temperature is greater than 80%.

[0123] It can be seen from the comparison between the embodiments and the comparative examples that when there is no inorganic nanomaterial in the preparation raw material, the temperature resistance is insufficient and the high-temperature emulsification efficiency is poor; when the third compound is missing, the high-temperature emulsification efficiency is low; when the third compound is replaced, the high-temperature emulsification efficiency is greatly reduced; and the high-temperature emulsification efficiency of the emulsifier provided by the present invention is higher than that of the conventionally used Span-80.

[0124] Table 2

[0125]

[0126]

[0127] As can be seen from Table 2, the emulsifier provided by the present invention adopts specific raw materials and structural design, so that the emulsifier has a higher demulsification voltage under normal temperature and high temperature conditions, indicating that the emulsion has good stability at high temperature and good high temperature resistance; wherein the emulsifiers synthesized in Examples 1-5 and Example 7 can also reach a demulsification voltage of more than 460V under high temperature conditions. The amount of the second compound, the third compound and the fourth compound in the raw materials of the emulsifiers synthesized in Examples 6 and 8 is small, so that the demulsification voltage of the emulsifier after high temperature is less than 400V; the amount of the second compound, the third compound and the fourth compound used in the emulsifier synthesized in Example 9 is too much, and the effective content of the synthesized emulsifier with high temperature resistance is less, which also makes the demulsification voltage after high temperature lower than 400V; the amount of the fourth compound of the emulsifier synthesized in Example 10 is small, so that the demulsification voltage after high temperature is greatly reduced to only 156V; the fourth compound of the emulsifier synthesized in Example 11 is not added in steps, resulting in a low final high temperature resistant emulsifier product, so that the demulsification voltage after high temperature is lower than 400V.

[0128] It can be seen from the comparison between the embodiments and the comparative examples that when there is no inorganic nanomaterial in the preparation raw material, the temperature resistance is insufficient and the demulsification voltage is significantly reduced; when the third compound is missing, the demulsification voltage is extremely low and the high temperature resistance is poor; when the third compound is replaced, the demulsification voltage of the obtained high temperature emulsifier is greatly reduced and the high temperature resistance is poor; and the demulsification voltage of the emulsifier provided by the present invention at high temperature is much higher than that of the conventionally used Span-80, and the high temperature resistance is better.

[0129] Table 3

[0130]

[0131]

[0132] Table 4

[0133]

[0134]

[0135] It can be seen from Table 3 and Table 4 that the emulsifier provided by the present invention adopts specific raw materials and structural design, so that the drilling fluid including the emulsifier has good stability, high temperature resistance, and good fluid loss reduction performance; the demulsification voltage of all drilling fluids before aging is about 800V, indicating that the emulsification rate of the drilling fluid is good, and the apparent viscosity of the drilling fluid is lower than that of the drilling fluid using Span-80 as an emulsifier, but its dynamic shear force is relatively higher, showing good low-viscosity and high-shear rheological properties. After high-temperature aging at 260°C, the demulsification voltage of the drilling fluid including the emulsifier synthesized in Examples 1-7 increased to a certain extent, proving that it maintained good emulsification stability and still maintained good rheology; however, when the formula ratio of the synthetic emulsifier exceeded the authority range, the temperature resistance of the obtained emulsifier was greatly reduced, as shown in Examples 8 and 9, and the rheology deteriorated, and the high-temperature and high-pressure filtration loss was difficult to control; and the low content of the fourth compound in the synthetic emulsifier would also lead to a decrease in the temperature resistance of the emulsifier, resulting in system instability, as shown in Example 10; at the same time, if the fourth compound is not added in a step-by-step manner for synthesis, the temperature resistance of the high-temperature resistant emulsifier will be reduced, and the system will also be unstable, as shown in Example 11.

[0136] It can be seen from the comparison of the embodiments and the comparative examples that when the inorganic nanomaterial is not present in the preparation raw materials, the heat resistance is insufficient, the demulsification voltage is significantly reduced after aging, the rheological parameters are greatly reduced, and hard precipitation occurs, the stability is poor, and the filtration loss reduction performance is poor; when the third compound is missing, the demulsification voltage is extremely low, the rheological parameters are greatly reduced, it is difficult to maintain the emulsion stability of the drilling fluid, it is more likely to cause the sedimentation of the weighted material, the high temperature resistance is poor, and the filtration loss reduction performance is poor; when the third compound is replaced, the demulsification voltage of the obtained high temperature emulsifier is greatly reduced, the rheological properties are deteriorated, the filtration loss is greatly increased, and poor high temperature resistance is shown. In addition, the emulsifier provided by the present invention makes the rheological properties, stability and filtration loss reduction performance of the drilling fluid at high temperature better than the conventionally used Span-80, and the high temperature resistance is better.

[0137] In summary, the ultra-high temperature resistant emulsifier provided by the present invention can be applied to oil-based drilling fluid systems, can effectively maintain the emulsion stability of the drilling fluid system before and after high-temperature aging, improve the high-temperature sedimentation stability of the system, and at the same time enhance the filtration loss reduction effect of the drilling fluid, and its temperature resistance can reach 260°C.

[0138] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An emulsifier for oil-based drilling fluid, characterized in that: The raw materials for preparing the oil-based drilling fluid emulsifier include a first compound, a second compound, a third compound and a fourth compound; The first compound includes a modified inorganic filler; The modified inorganic filler contains amino groups in its molecular structure; The second compound includes a long-chain unsaturated acid compound; The third compound includes a compound containing a hydroxyl group and an amino group, and / or a compound containing a carboxyl group and an amino group; The fourth compound includes a propylene diamine compound.

2. The emulsifier for oil-based drilling fluid according to claim 1, characterized in that: The modified inorganic filler includes at least one of modified silicon dioxide, modified titanium dioxide or modified aluminum oxide; Preferably, the modifier in the modified inorganic filler includes an amino-containing silane coupling agent; Preferably, the amino-containing silane coupling agent includes at least one of aminopropyltriethoxysilane, aminopropyltrimethoxysilane, anilinomethyltriethoxysilane, anilinomethyltrimethoxysilane, aminoethylaminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane or N-(β-aminoethyl)-γ-aminopropyltriethoxysilane; Preferably, the molar amount of the inorganic filler in the modified inorganic filler is 1 mol, and the molar amount of the modifier is 0.5 to 2.5 mol, preferably 0.75 to 2.5 mol, and more preferably 1 to 2.5 mol; Preferably, the particle size of the inorganic filler is 10 to 50 nm.

3. The emulsifier for oil-based drilling fluid according to claim 1 or 2, characterized in that: The long-chain unsaturated acid compounds include C12-C22 unsaturated fatty acids; Preferably, the long-chain unsaturated acid compound includes at least one of vegetable oleic acid, linolenic acid, linoleic acid, myristic acid, palmitoleic acid or rapeseed oleic acid; Preferably, based on the molar amount of the inorganic filler in the modified inorganic filler being 1 mol, the molar amount of the second compound is 1 to 5 mol, preferably 1.5 to 5 mol, and more preferably 2 to 5 mol.

4. The emulsifier for oil-based drilling fluid according to any one of claims 1 to 3, characterized in that: The third compound includes at least one of hydroxyethylethylenediamine, N-(2-hydroxypropyl)ethylenediamine or ethylenediaminetetraacetic acid; Preferably, based on the molar amount of the inorganic filler in the modified inorganic filler being 1 mol, the molar amount of the third compound is 0.5 to 1.5 mol, preferably 0.6 to 1.5 mol, and more preferably 0.75 to 1.5 mol.

5. The emulsifier for oil-based drilling fluid according to any one of claims 1 to 4, characterized in that: The fourth compound includes at least one of propylene diamine, tallow 1,3-propylene diamine, N-oleyl-1,3-propylene diamine or N-stearyl-1,3-propylene diamine; Preferably, based on the molar amount of the inorganic filler in the modified inorganic filler being 1 mol, the molar amount of the fourth compound is 1 to 5 mol, preferably 1.5 to 5 mol, and more preferably 2 to 5 mol.

6. A method for preparing an emulsifier for oil-based drilling fluid according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: The first compound, the second compound, the third compound and the fourth compound are reacted to obtain the oil-based drilling fluid emulsifier.

7. The preparation method according to claim 6, characterized in that: The reaction comprises: mixing the first compound with the second compound and the third compound to perform a first contact reaction to obtain a first intermediate; performing a second contact reaction on the first intermediate and 40-50% of the fourth compound to obtain a second intermediate; performing a third contact reaction on the second intermediate and the remaining fourth compound to obtain the oil-based drilling fluid emulsifier; Preferably, the temperature of the first contact reaction is 45-95°C, the time is 0.5-2.5h, more preferably the temperature is 50-65°C, the time is 1-2h; Preferably, the temperature of the second contact reaction is 120-190°C, and the time is 4-12 hours, and more preferably, the temperature is 150-170°C, and the time is 6-8 hours; Preferably, the temperature of the third contact reaction is 60-100°C and the time is 1-5 hours, and more preferably the temperature is 70-90°C and the time is 2-4 hours; Preferably, the first contact reaction, the second contact reaction and the third contact reaction are each independently carried out under negative pressure conditions.

8. The preparation method according to claim 6 or 7, characterized in that: The preparation method of the first compound comprises: Mixing a modifier, an inorganic filler and a solvent, and reacting them to obtain the first compound; Preferably, the reaction is carried out under alkaline conditions; Preferably, the reaction temperature is 40-95°C, the time is 0.5-4h, more preferably the temperature is 50-70°C, the time is 1-3h; Preferably, the solvent comprises an alcohol-water mixed solution.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The preparation method comprises: (1) mixing a modifier, an inorganic filler and a solvent, and reacting them under alkaline conditions at a temperature of 40 to 95° C. for 0.5 to 4 hours to obtain the first compound; (2) mixing the first compound with the second compound and the third compound, and reacting them at 45 to 95° C. for 0.5 to 2.5 hours to obtain a first intermediate; (3) reacting the first intermediate with 40-50% of the fourth compound at 120-190° C. for 4-12 hours to obtain a second intermediate; (4) reacting the second intermediate with the remaining fourth compound at 60-100° C. for 1-5 hours to obtain the oil-based drilling fluid emulsifier.

10. An oil-based drilling fluid, characterized in that: The oil-based drilling fluid comprises the emulsifier for oil-based drilling fluid according to any one of claims 1 to 5; Preferably, the mass percentage of the emulsifier in the oil-based drilling fluid is 4-6%.

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