阅读说明：本技术 一种改性有机膨润土及其制备方法与应用 (Modified organic bentonite and preparation method and application thereof ) 是由 沈亚欣 于 2019-11-22 设计创作，主要内容包括：本发明涉及钻井液技术领域,公开一种改性有机膨润土,按重量份计包括：高纯钠土40～60份；乳化剂5～15份；插层剂25～55份；其中乳化剂为脂肪酸多乙烯多胺酰化物和脂肪酸二乙醇酰胺的混合物。该膨润土的制备方法为：(1)在反应釜中加入高纯钠土和水,打浆搅拌均匀；(2)将反应釜升温加入插层剂,搅拌混合；(3)将反应釜中物料降温后压滤；(4)将压滤后的物料放入混合设备,升温后加入乳化剂,捏合2～4h后,继续升温,捏合2～4h,倒出的物料经干燥、粉碎得到改性有机膨润土。该膨润土应用在油基钻井液中,能够同时提高钻井液的粘稠度和乳化稳定性,在油气田钻探工程中具有极好的应用前景。(The invention relates to the technical field of drilling fluid, and discloses modified organic bentonite, which comprises the following components in parts by weight: 40-60 parts of high-purity sodium soil; 5-15 parts of an emulsifier; 25-55 parts of an intercalation agent; wherein the emulsifier is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide. The preparation method of the bentonite comprises the following steps: (1) adding high-purity sodium soil and water into a reaction kettle, pulping and stirring uniformly; (2) heating the reaction kettle, adding the intercalation agent, stirring and mixing; (3) cooling the materials in the reaction kettle, and then performing filter pressing; (4) and (3) putting the filter-pressed materials into a mixing device, heating, adding an emulsifier, kneading for 2-4 h, continuing heating, kneading for 2-4 h, drying and crushing the poured materials to obtain the modified organic bentonite. The bentonite is applied to the oil-based drilling fluid, can improve the viscosity and the emulsion stability of the drilling fluid simultaneously, and has a good application prospect in the drilling engineering of oil and gas fields.)

1. The modified organic bentonite is characterized by comprising the following components in parts by weight:

40-60 parts of high-purity sodium soil;

5-15 parts of an emulsifier;

25-55 parts of an intercalation agent;

the emulsifier is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide.

2. The modified organobentonite according to claim 1, wherein the emulsifier has a mass ratio of fatty acid polyethylene polyamine acylate to fatty acid diethanolamide of 1: 0.5 to 2.

3. The modified organic bentonite according to claim 1, wherein the emulsifier is prepared by stirring and blending fatty acid polyethylene polyamine acylate and fatty acid diethanolamide at 30-80 ℃ for 5-20 min.

4. The modified organic bentonite as claimed in any one of claims 1 to 3, wherein the fatty acid polyethylene polyamine acylate is prepared by amidating stearic acid and polyethylene polyamine.

5. The modified organobentonite according to claim 4, wherein the fatty acid polyethylene polyamine acylate is prepared by dehydration reaction of 500 to 700 parts by weight of stearic acid and 80 to 150 parts by weight of polyethylene polyamine at 160 to 180 ℃ for 4 to 8 hours.

6. The method for preparing modified organobentonite according to any of claims 1 to 5, comprising the steps of:

(1) adding 40-60 parts by weight of high-purity sodium soil and 500-2000 parts by weight of water into a reaction kettle, pulping and uniformly stirring for later use;

(2) heating the reaction kettle to 40-80 ℃, adding 25-55 parts by weight of an intercalator, stirring for more than 2 hours, and uniformly mixing;

(3) cooling the materials in the reaction kettle, and then performing filter pressing;

(4) and (3) putting the filter-pressed materials into a mixing device, heating to 60-80 ℃, adding 5-15 parts by weight of an emulsifier, kneading for 2-4 hours, heating to 100-120 ℃ again, kneading for 2-4 hours, and drying and crushing the poured materials to obtain the modified organic bentonite.

7. Use of the modified organobentonite according to any of claims 1 to 5 in oil-based drilling fluids.

8. The application of the modified organic bentonite in the oil-based drilling fluid is characterized in that the addition amount of the modified organic bentonite is 1-5 wt%.

9. An emulsifier, which is characterized in that the emulsifier is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide, and the mass ratio of the fatty acid polyethylene polyamine acylate to the fatty acid diethanolamide is 1: 0.5 to 2.

10. Use of an emulsifier according to claim 9 in an oil-based drilling fluid.

Technical Field

The invention relates to the technical field of drilling fluid, and particularly relates to modified organic bentonite and a preparation method and application thereof.

Background

The drilling fluid is an essential functional working fluid in the drilling process of oil and gas fields. It plays a role in carrying and suspending drill cuttings, stabilizing the well wall and the formation pressure in balance, cooling and lubricating the drill bit, transferring hydrodynamic force, and the like. The drilling fluid can be divided into oil-based drilling fluid and water-based drilling fluid according to different base fluids. The oil-based drilling fluid has the advantages of high temperature resistance, good salt resistance, contribution to well wall stability, strong lubricity, small damage to an oil-gas layer, reusability and the like, so that the oil-based drilling fluid is widely applied. The oil-based drilling fluid becomes a first choice system of high-difficulty high-temperature deep wells, horizontal wells, large-inclination directional wells and various complex formations, and can also be widely used as stuck freeing fluid, perforation completion fluid, workover fluid and the like.

The oil-based drilling fluid is an emulsion with certain viscosity, the emulsion stability and the viscosity stability of the emulsion influence the performance of the drilling fluid, and particularly, various engineering accidents are possibly caused when the emulsion breaking and the viscosity sharply drop under the high-temperature condition. In order to improve the emulsion stability and viscosity of the oil-based drilling fluid, the prior art mainly improves the fluid viscosity through organic bentonite, and improves the effect of the bentonite in the oil-based drilling fluid through multi-aspect modification of the bentonite.

Patent CN103482638A discloses a method for manufacturing organobentonite, comprising the following steps: 1) pulping; 2) precipitating slurry; 3) removing sand by the cyclone sand remover; 4) further filtering solid impurities by using a horizontal centrifuge; 5) performing liquid-liquid separation by a disc centrifuge to obtain concentrated sodium-based montmorillonite slurry; 6) measuring the solid content; 7) adding soda ash; 8) heating, adding sulfuric acid to adjust the pH value, and keeping the temperature; 9) organic covering reaction: adding white oil and octadecyl trimethyl ammonium chloride; 10) pressing to dry; 11) and (5) drying.

Patent CN106167266A discloses a process for preparing organobentonite from composite intercalation agent, which comprises the following steps: (1) pulping; (2) removing sand by the cyclone sand remover; (3) further filtering solid impurities by using a horizontal centrifuge; (4) measuring and controlling the solid content; (5) adding an intercalation agent sodium dodecyl sulfate which accounts for 10-13% of the total weight of the total soil solids into the slurry obtained in the step (3), and stirring and reacting for 1-2 hours; (6) heating to 70-80 ℃, adding an intercalation agent of octadecyl trimethyl ammonium chloride accounting for 45-55% of the total weight of the total soil solids, and stirring for reaction for 1-2 hours to obtain mixed slurry of the organic bentonite and water; (7) pressing to dry; (8) and (5) drying.

Although the modified bentonite has the characteristics of high temperature resistance, stable performance and the like on the oil-based drilling fluid, the modified bentonite can continuously play a role under the drilling operation condition with a wider temperature range. However, these technologies mainly aim to increase the viscosity of the organic soil in the solvent, most of the organic bentonite has no emulsifying property, and an additional emulsifier is required to increase the emulsion stability of the drilling fluid. The possibility of mismatching between different emulsifiers and modified bentonite exists, in the using process of the drilling fluid, the emulsifiers need to be selected and blended by professionals, the process flow is complicated, and the effect is not easy to control.

Patent CN106147729A discloses an oil-based drilling fluid and a preparation method thereof, wherein the oil-based drilling fluid comprises the following components in parts by weight: 85-95 parts of base oil, 2-6 parts of asphalt composition, 1-5 parts of organic soil, 2-4 parts of emulsifier, 1-3 parts of wetting agent, 0.5-2 parts of alkalinity regulator and weighting agent.

Patent CN107777696A discloses a preparation method of organic bentonite, grinding calcium bentonite to fineness of 100-325 meshes by a Raymond machine, adding water for pulping, adding sodium carbonate for uniform mixing, and aging to obtain sodium bentonite slurry; adding the sodium bentonite slurry and polyacrylamide into a reaction kettle, reacting, performing filter pressing, then transferring into a modifying machine, adding dibutyl phthalate and an emulsifier into the modifying machine, modifying, drying, adding into a mixing roll, and mixing with dimethyl octadecyl benzyl ammonium chloride to obtain the organic bentonite.

According to the technology, the emulsifier is added into the bentonite by a modification method, so that the viscosity of the drilling fluid can be improved, but the gelling effect is insufficient, the emulsion stability of the bentonite is still not ideal, and more modified bentonite for improving the emulsion stability and viscosity of the drilling fluid needs to be explored and developed.

Disclosure of Invention

The invention aims to provide the modified organic bentonite, which has an obvious thickening effect on oil-based drilling fluid, can obtain the drilling fluid with good emulsifying property without additionally adding an emulsifier, and simplifies the process flow for preparing the drilling fluid.

In order to achieve the purpose, the invention adopts the technical scheme that:

the modified organic bentonite comprises the following components in parts by weight:

40-60 parts of high-purity sodium soil;

5-15 parts of an emulsifier;

25-55 parts of an intercalation agent;

the emulsifier is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide.

In oil-based drilling fluids, in order to be able to form stable emulsions, this is generally achieved by: 1) forming an adsorption film with certain strength at an oil/water interface; 2) reducing the oil-water interfacial tension; 3) increasing the viscosity of the external phase. Like the common emulsifier, the emulsifier of the invention has surface activity, can reduce the oil/water interfacial tension, simultaneously forms an adsorption film on the interface, and has emulsifying property. But the difference is that the selected emulsifier is a mixture, a more compact close-packed composite membrane can be formed at an oil-water interface, the stability is better, and meanwhile, the selected emulsifier has good compatibility with bentonite modified by the intercalating agent, and can form uniform and stable modified organic bentonite.

Preferably, the modified organic bentonite comprises the following components in parts by weight:

40-60 parts of high-purity sodium soil;

10-15 parts of an emulsifier;

25-40 parts of an intercalation agent;

the emulsifier is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide. The proportion of the emulsifier is properly increased, and the lipophilicity of the modified organic bentonite can be enhanced.

In the emulsifier, the mass ratio of fatty acid polyethylene polyamine acylate to fatty acid diethanolamide is 1: 0.5-2, preferably the mass ratio of the two is 1: 1. The two emulsifiers are compounded and used more than a single emulsifier, a more compact close-packed composite film is formed at an oil-water interface, and the emulsifier is used and has better emulsion stability.

The emulsifier is prepared by stirring and blending fatty acid polyethylene polyamine acylate and fatty acid diethanolamide at the temperature of 30-80 ℃ for 5-20 min. The two materials are mixed in a physical mixing process, the temperature slightly higher than the melting point is generally selected to be stirred and blended optimally, and the melting point of the two materials is about 40 ℃, so that the preferred blending time is 10-15 min at 45-55 ℃.

The fatty acid polyethylene polyamine acylate is prepared by amidating stearic acid and polyethylene polyamine. Amidation as referred to herein refers to the reaction of carboxylic acids with amine groups as is well known to those skilled in the art, and the fatty acid polyethylene polyamine acylates described can be prepared by reacting stearic acid with polyethylene polyamines according to the reaction conditions customary for such reactions.

Preferably, the fatty acid polyethylene polyamine acylate is prepared by dehydration reaction of 500-700 parts by weight of stearic acid and 80-150 parts by weight of polyethylene polyamine at 160-180 ℃ for 4-8 h.

Further preferably, the mass part ratio of the stearic acid to the polyethylene polyamine is 500-600: 80-120, the obtained emulsifier has the best effect.

The high-purity sodium soil is a product obtained by performing rough concentration, pulping, sand removal and sodium treatment on bentonite ores in the market. Preferably, the high purity sodium soil has a moisture content of < 10%, a sand content of < 2%, and a cation exchange capacity of >50mmol per 100 g.

The intercalation agent is a cationic surfactant and comprises any one or more of octadecyl trimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride and dioctadecyl methyl benzyl ammonium chloride.

The invention also provides a preparation method of the modified organic bentonite, which comprises the following steps:

(1) adding 40-60 parts by weight of high-purity sodium soil and 500-2000 parts by weight of water into a reaction kettle, adjusting the pH to 4-6 by using sulfuric acid or citric acid, pulping and uniformly stirring, and controlling the stirring speed to be 20-50 r/min for later use; the pH value of the slurry can be adjusted by other inorganic acid or inorganic base, or not.

(2) Heating the reaction kettle to 40-80 ℃, adding 25-55 parts by weight of an intercalator, stirring for more than 2 hours, and uniformly mixing;

(3) cooling the materials in the reaction kettle, and then performing filter pressing;

(4) and (3) putting the filter-pressed material into a mixing device, heating, adding 5-15 parts by weight of an emulsifier, kneading for 2-4 hours, heating again, kneading for 2-4 hours, and drying and crushing the poured material to obtain the modified organic bentonite.

The high-purity sodium soil has strong hydrophilicity, is modified by the intercalation agent and then is changed from hydrophilicity to lipophilicity, and is heated and kneaded with the emulsifier to ensure that the emulsifier is fully swelled for secondary intercalation, and the obtained modified organic bentonite has stronger lipophilicity and can be better dispersed in oil products, so that not only can colloid with higher viscosity be formed, but also better gelling performance can be realized in the oil products.

In order to be more beneficial to the dispersion of the materials, the intercalation agent added in the step (2) can be prepared into an aqueous solution with the concentration of 5-20%.

In the step (3), the temperature of the reaction materials is reduced to 20-40 ℃, the materials are subjected to filter pressing by a plate-and-frame filter press, and the technological parameters of the plate-and-frame filter press are as follows: feeding concentration is 6-10%, initial filter pressing pipeline pressure is less than 0.5MPa, pipeline pressure rises to about 1.5MPa, intermittent grouting is started, filter pressing is carried out for 10-16 hours, and filter pressing is completed.

In the step (4), the temperature of the mixing equipment is 60-80 ℃ when the emulsifier is added, kneading is carried out for 2-4 hours, the emulsifier is uniformly mixed and dispersed at a relatively low temperature, then the temperature is raised to 100-120 ℃ again, and the emulsifier is transferred to the interlayer of the montmorillonite by using high temperature, so that secondary intercalation is realized.

The modified organic bentonite provided by the invention is applied to the oil-based drilling fluid, and can simultaneously improve the viscosity and the emulsification stability of the oil-based drilling fluid.

The modified organic bentonite is applied to the oil-based drilling fluid, and the addition amount of the modified organic bentonite is 1-5 wt%.

Compared with the conventional organic soil for the oil-based drilling fluid, the modified organic bentonite provided by the invention is firstly modified by intercalation of the intercalation agent and then modified by secondary intercalation of the emulsifier, and the modified organic bentonite has stronger lipophilicity and can be better dispersed in an oil product, so that a colloid with higher viscosity can be formed, and the colloid has better gelling property in the oil product. And in the modification process, the used emulsifier has good emulsifying property, so that the modified organic montmorillonite has good emulsifying stability in the oil-based drilling fluid.

The invention also provides an emulsifier, which is a mixture of fatty acid polyethylene polyamine acylate and fatty acid diethanolamide, wherein the mass ratio of the fatty acid polyethylene polyamine acylate to the fatty acid diethanolamide is 1: 0.5 to 2.

The emulsifier of the invention can be independently applied to oil-based drilling fluid, can improve the emulsion stability of the drilling fluid, or can be used together with other bentonite.

Compared with the prior art, the invention has the following beneficial effects:

(1) the modified organic bentonite has obvious thickening effect in the nonpolar base liquid, and solves the problem that the modified organic bentonite does not form gel and thicken in the nonpolar base liquid in the prior art;

(2) the modified organic bentonite has good emulsifying property, and an emulsifier is not required to be additionally added when the drilling fluid is prepared, so that the problem of poor emulsifying property of a product obtained by the prior art is solved;

(3) the modified organic bentonite is applied to the oil-based drilling fluid, can improve the viscosity and the emulsion stability of the drilling fluid at the same time, has multiple properties, and has a good application prospect in the drilling engineering of oil and gas fields.

Drawings

FIG. 1 is a schematic diagram of the preparation process of modified organobentonite according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.

In the following embodiment, high purity sodium soil is purchased from Liaoning Huaxiang Bentonite GmbH; octadecyl trimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride and dioctadecyl benzyl ammonium chloride are purchased from Solvay Fine chemical Co., Ltd; the same organobentonite as commercially available in comparative example 1 was purchased from VG-69, MI Swaco, and other raw materials such as stearic acid, polyethylene polyamine, stearic acid diethanolamide, etc. were purchased from commercial sources.

FIG. 1 is a schematic diagram of the preparation process of the modified organobentonite of the invention, which comprises mixing high-purity sodium soil with water, pulping, heating, adding an intercalation agent, stirring, intercalating, cooling, press-filtering and dehydrating the materials; heating the filter-pressed and dehydrated materials, adding an emulsifier, and kneading for 2-4 hours; and then, continuously heating and kneading the materials for 2-4 hours, and drying and crushing the materials to obtain the modified organic bentonite.