阅读说明：本技术 一种合成基钻井液用乳化剂及其制备方法 (Emulsifier for synthetic base drilling fluid and preparation method thereof ) 是由 王磊磊 闫晓婷 郭剑梅 陈庭贵 黄臣 王禹 李晓涵 张鹏 刘强 刘国 赵颖 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种合成基钻井液用乳化剂及其制备方法,该乳化剂由烷基葡萄糖酰胺、阴离子表面活性剂、极性溶剂和非极性溶剂组成。其制备方法如下：将葡萄糖甲胺和脂肪酸或脂肪酸酯加至极性溶剂中,在醇钠催化剂的作用下,回流反应2-5小时,生成烷基葡萄糖酰胺溶液,而后加入非极性溶剂和阴离子表面活性剂,搅拌均匀后得到产品。其中烷基葡萄糖酰胺的分子结构式如式Ⅰ所示。该方法工艺简单,产率较高,所得的乳化剂具有无毒、易生物降解、乳化能力强的特点。(The invention discloses an emulsifier for synthetic base drilling fluid and a preparation method thereof. The preparation method comprises the following steps: adding glucose methylamine and fatty acid or fatty acid ester into a polar solvent, carrying out reflux reaction for 2-5 hours under the action of a sodium alkoxide catalyst to generate an alkyl glucosamide solution, then adding a non-polar solvent and an anionic surfactant, and uniformly stirring to obtain the product. Wherein the molecular structural formula of the alkyl glucose amide is shown as a formula I. The method has the advantages of simple process, high yield, and high emulsifying capacity, and the obtained emulsifier has the characteristics of no toxicity, easy biodegradation.)

1. An emulsifier for synthetic base drilling fluid is characterized in that the emulsifier is compounded by alkyl glucose amide, anionic surfactant and nonpolar solvent; wherein the content of the first and second substances,

the alkyl glucose amide is prepared from 27-50 parts by weight of glucose methylamine, 29-43 parts by weight of fatty acid or fatty acid ester, 9-27 parts by weight of polar solvent and 0.12-0.16 part by weight of sodium alkoxide, and the molecular structural formula is as follows:

wherein n is any integer of 5-17, and n is an odd number; the polar solvent is C₁～C₄The small molecule monohydric or dihydric alcohol of (a);

the anionic surfactant is 1-3 parts by weight of sulfate salt type anionic surfactant;

7-9 parts by weight of a non-polar solvent, and the synthetic base oil has a kinematic viscosity of 2-6 mm at 40 DEG C²A synthetic base oil per second.

2. The emulsifier for the synthetic-base drilling fluid according to claim 1, wherein the fatty acid is a saturated fatty acid having a carbon chain length of 6 to 18, and the fatty acid ester is a methyl ester of a saturated fatty acid having a carbon chain length of 6 to 18.

3. The emulsifier for synthetic-based drilling fluids according to claim 2, wherein the fatty acid is caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid or stearic acid; the fatty acid ester is methyl caproate, methyl caprylate, methyl caprate, methyl laurate, methyl myristate, methyl palmitate or methyl stearate.

4. The emulsifier for synthetic-based drilling fluid according to claim 1, wherein the sulfate ester type anionic surfactant is fatty alcohol sulfate, fatty alcohol polyoxyethylene ether sulfate, glycerin fatty acid monoester sulfate or sulfated sodium ricinoleate.

5. The emulsifier for synthetic-based drilling fluids according to claim 1, wherein the polar solvent is at least one of ethanol, propanol, butanol, propylene glycol.

6. The emulsifier for synthetic-based drilling fluid according to claim 1, wherein the synthetic base oil is a gas oil-based synthetic base oil, a poly α -olefin-based synthetic base oil, a synthetic ester-based synthetic base oil, an internal olefin-based synthetic base oil, or a polyether-based synthetic base oil.

7. The method of claim 1 wherein the sodium alkoxide is sodium methoxide or sodium ethoxide.

8. A method of preparing an emulsifier for a synthetic based drilling fluid according to claim 1, comprising the steps of: adding a mixture of glucose methylamine and fatty acid or a mixture of glucose methylamine and fatty acid ester into a polar solvent, uniformly mixing, adding a sodium alkoxide catalyst, heating to 120-130 ℃, performing reflux reaction for 2-5 hours to generate an alkyl glucose amide solution, adding a non-polar solvent and an anionic surfactant, and uniformly stirring to obtain an emulsifier product.

9. The preparation method of the emulsifier for the synthetic-base drilling fluid, according to claim 8, is characterized in that the feeding molar ratio of the meglumine to the fatty acid is 1: 0.8-1.22; the feeding molar ratio of the glucose methylamine to the fatty acid ester is 1: 1.02-1.10.

Technical Field

The invention relates to the technical field of oilfield chemicals, and particularly relates to an emulsifier for synthetic base drilling fluid and a preparation method thereof.

Background

The oil-based drilling fluid is a drilling fluid system which is composed of oil serving as a continuous phase, water serving as a dispersed phase, and an emulsifier, a shear enhancing agent, a plugging agent, a filtrate loss reducer, alkali and other chemical agents. Compared with water-based drilling fluid, the drilling fluid has the advantages of good lubrication, pollution resistance, high temperature resistance, strong inhibition, oil-gas layer protection and the like, so that the drilling fluid is more and more widely applied to difficult wells such as deep wells, ultra-deep wells, wells with complex structures, special stratum wells, large-displacement horizontal wells and the like.

However, with the increasing number of complex wells and the stricter environmental regulations, higher demands are made on the performance of the drilling fluid. The synthetic base drilling fluid is produced under the condition that the water base drilling fluid can not meet the performance requirements of complex conditions under the well and the traditional mineral oil base (diesel oil and white oil) drilling fluid can not meet the environmental protection requirements. The synthetic base drilling fluid has the advantages of low toxicity, biodegradability, no fluorescence and the like on the basis of the advantages of excellent temperature resistance, strong inhibition, good lubricity and the like of the traditional mineral oil drilling fluid, and is widely used in ocean deep water and environment sensitive areas.

The emulsifier is the most key treating agent in the oil-based drilling fluid system, can reduce the interfacial tension between oil and water, forms an adsorption film with certain strength at an oil-water interface, enables a water phase to form uniform small droplets in an oil phase, and improves the stability of the whole water-in-oil system. At present, the emulsifier for the oil-based drilling fluid mainly comprises nonionic surfactants such as span, tween and naphthenic acid amide, anionic surfactants such as calcium stearate, calcium oleate and iron naphthenate, and macromolecular polyamide and polyether surfactants, and the reasonable compounding of the emulsifier has a good emulsifying effect, but has the defects of toxicity, difficult degradation and the like, and is not suitable for being continuously used as the emulsifier for the synthetic-base drilling fluid.

Disclosure of Invention

The invention aims to provide the emulsifier for the synthetic base drilling fluid, which has the characteristics of no toxicity, easy biodegradation, strong emulsifying capacity and the like.

The invention also aims to provide a preparation method of the emulsifier for the synthetic base drilling fluid.

Therefore, the technical scheme of the invention is as follows:

an emulsifier for synthetic base drilling fluid is prepared by compounding alkyl glucamide, anionic surfactant and nonpolar solvent; wherein the content of the first and second substances,

the alkyl glucose amide is prepared from 27-50 parts by weight of glucose methylamine, 29-43 parts by weight of fatty acid or fatty acid ester, 9-27 parts by weight of polar solvent and 0.12-0.16 part by weight of sodium alkoxide, and the molecular structural formula is as follows:

wherein n is any integer of 5-17, and n is an odd number; the polar solvent is C₁～C₄The small molecule monohydric or dihydric alcohol of (a);

the anionic surfactant is 1-3 parts by weight of sulfate salt type anionic surfactant;

7-9 parts by weight of non-polar solvent, wherein the synthetic base oil has a kinematic viscosity of 2-6 mm at 40 DEG C²A synthetic base oil per second.

In the formula components of the emulsifier for the synthetic base drilling fluid, the alkyl glucamide belongs to a non-ionic surfactant, has low toxicity and is biodegradable, and is used as a raw material for preparing the alkyl glucamide: starch and grease exist in large quantities in nature, belong to renewable resources, and have the characteristics of raw material acquisition and low cost; meanwhile, the glucose chain segment in the alkyl glucose amide molecular chain has a large amount of hydroxyl groups, so that the alkyl glucose amide molecular chain has strong hydrophilicity, has strong surface activity after forming an amide molecular chain with an aliphatic hydrophobic chain segment with a certain length, and can realize the emulsification stability at a lower concentration, so that the alkyl glucose amide molecular chain segment is used as an emulsifier in the synthetic base drilling fluid, and can avoid the defect of poor environmental protection of the traditional emulsifier while playing an emulsification role. The purpose of introducing the nonpolar solvent is to improve the fluidity of the product and facilitate the field charging construction; the anionic surfactant is added to moderately break up intermolecular association formed by the alkyl glucamide due to polyhydroxy, so that the fluidity of the product is increased, and the nonionic/anionic composite surfactant is formed with the alkyl glucamide to achieve the purpose of synergy.

Preferably, the fatty acid is a saturated fatty acid with a carbon chain length of 6-18, and the fatty acid ester is a methyl ester of a saturated fatty acid with a carbon chain length of 6-18.

Preferably, the fatty acid is caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid or stearic acid; the fatty acid ester is methyl caproate, methyl caprylate, methyl caprate, methyl laurate, methyl myristate, methyl palmitate or methyl stearate.

Preferably, the sulfate ester type anionic surfactant is fatty alcohol sulfate, fatty alcohol-polyoxyethylene ether sulfate, glycerin fatty acid monoester sulfate or sulfated sodium ricinoleate.

Wherein the fatty alcohol sulfate is fatty alcohol sulfate with carbon number of 12-16, such as sodium dodecyl sulfate; the chemical structural formula of the fatty alcohol-polyoxyethylene ether sulfate is as follows: RO (CH)₂CH₂O)_n-SO₃Na, wherein n is 2 or 3, and R is an alkyl group having 12 to 15 carbon atoms; the glycerin fatty acid monoester sulfate is glycerin fatty acid monoester sulfate with 12-14 carbon atoms of fatty acid, such as sodium glycerin lauric acid monoester sulfate.

Preferably, the polar solvent is at least one of ethanol, propanol, butanol and propylene glycol.

Preferably, the synthetic base oil is a gas oil synthetic base oil, a poly α -olefin synthetic base oil, a synthetic ester synthetic base oil, an internal olefin synthetic base oil or a polyether synthetic base oil, the synthetic base oils are prepared by a chemical synthesis or refining method, toxic and harmful substances such as aromatic hydrocarbons are removed, and the synthetic base oils have the properties of environmental protection, good fluidity, no fluorescence, low freezing point and the like.

Preferably, the sodium alkoxide is sodium methoxide or sodium ethoxide.

A preparation method of an emulsifier for synthetic base drilling fluid comprises the following steps: adding a mixture of glucose methylamine and fatty acid or a mixture of glucose methylamine and fatty acid ester into a polar solvent, uniformly mixing, adding a sodium alkoxide catalyst, heating to 120-130 ℃, performing reflux reaction for 2-5 hours to generate an alkyl glucose amide solution, adding a non-polar solvent and an anionic surfactant, and uniformly stirring to obtain an emulsifier product.

Preferably, the feeding molar ratio of the glucose methylamine to the fatty acid is 1: 0.8-1.22; the feeding molar ratio of the glucose methylamine to the fatty acid ester is 1: 1.02-1.10.

Compared with the prior art, the emulsifier for the synthetic base drilling fluid adopts the alkyl glucamide as the main component of the emulsifier for the synthetic base drilling fluid, has the characteristics of enhanced emulsifying capacity and environmental protection, low toxicity and easy degradation, is more suitable for being matched with environment-friendly synthetic base oil to form the synthetic base drilling fluid, enhances the dispersibility of the emulsifier product in the base oil by being supplemented with a small amount of anionic surfactant, and simultaneously forms a nonionic/anionic composite surfactant with the alkyl glucamide to achieve the purpose of synergy; the fluidity of the product is improved by introducing the nonpolar solvent, so that the field charging construction is facilitated; in addition, the preparation method of the emulsifier for the synthetic base drilling fluid is simple, has high yield, is suitable for industrial production and has good popularization and application prospects.

Detailed Description

The present invention will be further described with reference to the following examples, which are not intended to limit the scope of the invention in any way, in examples 1 to 13 and comparative examples, each component is commercially available, wherein the amount of each component added is specifically referred to parts by weight, and each of the gas oil-based synthetic base oil, poly α -olefin-based synthetic base oil, synthetic ester-based synthetic base oil, internal olefin-based synthetic base oil and polyether-based synthetic base oil has a kinematic viscosity (at 40 ℃) of 2 to 6mm²A commercial synthetic base oil per second.