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A method of modified Wei Lanjiao

A Welan gum and modification technology, which is applied in the field of preparation of modified Welan gum, can solve the problems of slow dissolution rate, low viscosity, low water solubility, etc., and achieve enhanced viscosity, increased viscosity, and increased crosslinking performance Effect

Active Publication Date: 2020-09-04
NANJING TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its own viscosity is not high, its water solubility is low, and its dissolution rate is slow, which are important factors that affect its use as a fracturing fluid thickener.

Method used

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  • A method of modified Wei Lanjiao
  • A method of modified Wei Lanjiao

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Dissolve 2.414g trisodium citrate dihydrate (8.208mmol, 3.04eq) in 50mL water, adjust the pH to about 3 with 1mol / L hydrochloric acid, and make solution I; in a three-necked flask, take 5g Velan gum (2.7mmol ) and 5g trimethyloctadecyl ammonium chloride are mixed in the toluene of 80ml under the condition of stirring, be mixed with the suspension of 62.5g / L, solution I is slowly added in this suspension, at rotating speed Stir at 450rpm to fully dissolve; react at normal pressure, 80°C, and 450rpm for 8h, take out the reaction solution, pour it into a large amount of absolute ethanol to precipitate the product, wash, filter with suction, and dry at 60°C for 24h. A modified Welan gum product is obtained. The product was dissolved in 400mL of 2wt% KCl solution and dissolved within 2h. Get the product and configure it as a 0.6wt% aqueous solution, and use the ZNN-D6 type six-speed rotational viscometer to measure the viscosity under the condition of 300r / min as 0.0494pa.s...

Embodiment 2

[0036] Dissolve 0.87g monosodium citrate (4.104mmol, 1.52eq) in 30mL water, adjust the pH to about 3 with 1mol / L hydrochloric acid, and make solution I; in a three-necked flask, take 5g Velan gum (2.7mmol) and 5g of trimethyloctadecyl ammonium chloride was mixed in 80ml of toluene under agitation to prepare a suspension of 62.5g / L. Solution I was slowly added to the suspension, and the rotation speed was 450rpm Stir under low pressure to allow it to fully dissolve; react under normal pressure, 80°C, 550rpm stirring conditions for 6h, take out the reaction solution, pour it into a large amount of absolute ethanol to precipitate the product, wash, suction filter, and dry at 60°C for 24h to obtain Modified Welan gum product. The product was dissolved in 400mL of 2wt% KCl solution and dissolved within 2h. Get the product and configure it as a 0.6wt% aqueous solution, and use the ZNN-D6 six-speed rotary viscometer to measure the viscosity at 300r / min at a speed of 0.0532pa.s.

Embodiment 3

[0038] Dissolve 1.39g (2.43eq) monosodium citrate in 30mL water, adjust the pH to about 3 with 1mol / L hydrochloric acid, and make solution I; in a three-necked flask, take 5g Velan gum and 5g trimethyloctadecane Hydroxyl ammonium chloride is mixed in the toluene of 80ml under the condition of stirring, is mixed with the suspension of 62.5g / L, and solution I is slowly added in this suspension, is that it is fully dissolved under the condition of 450rpm that the rotating speed is stirred; React under normal pressure, 80°C, 500rpm stirring conditions for 6h, take out the reaction solution, pour it into a large amount of absolute ethanol to precipitate the product, wash, filter with suction, and dry at 60°C for 24h to obtain the modified Welan gum product. The product was dissolved in 400mL of 2wt% KCl solution and dissolved within 2h. Get the product and configure it as a 0.6wt% aqueous solution, and use the ZNN-D6 type six-speed rotary viscometer to measure the viscosity at a sp...

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Abstract

The invention discloses a preparation method of modified welan gum. The method comprises the step that welan gum is reacted with citrate under the presence of an acidifier, a phase transfer catalyst and reaction solvent to obtain the modified welan gum. According to the modified welan gum prepared through the method, the crosslinking performance is improved, so that the problem is solved that thewelan gum is poor in water solubility; meanwhile, the viscosity of the welan gum is obviously enhanced, wherein the viscosity is improved compared with that of the unmodified welan gum.

Description

technical field [0001] The invention relates to a method for modifying microbial polysaccharides, in particular to a method for preparing modified Welan gum. Background technique [0002] Oil is a non-renewable energy source, and China has a huge demand for oil. However, China's oil fields have basically entered the middle and late stages of exploitation, and the rise of water cut and the decrease of oil layer permeability have become the main problems faced by oil exploitation. Fracturing of oil wells is a commonly used method to improve oil well permeability, improve oil recovery efficiency, and increase production. Water-based fracturing is one of the fracturing construction methods with the most mature technology and the greatest cost advantage. Traditional fracturing fluids use guar gum as a thickener, which results in slow dosing speed and low construction efficiency. [0003] Welan gum is a high-molecular polysaccharide polymer, which is generally made from corn st...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B37/00
CPCC08B37/006
Inventor 郭凯刘壮李昕
Owner NANJING TECH UNIV