Preparation method of polyanionic cellulose with ultrahigh viscosity for water-based drilling fluid

Abstract

The invention relates to the technical field of production of polyanionic cellulose, and discloses a preparation method of polyanionic cellulose with an ultrahigh viscosity for a water-based drilling fluid. The preparation method comprises the steps of: (1) uniformly mixing a sodium hydroxide aqueous solution with ethanol water solution to obtain an alcohol-alkali mixture with a temperature of 8-13 degrees centigrade; (2) after tearing up refined cotton with high degree of polymerization, putting into a kneader together with the alcohol-alkali mixture to alkalize the refined cotton at the low temperature; (3) after the alkalization is finished, adding an etherifying agent, adding the sodium hydroxide after the etherifying agent is completely added, and then raising the temperature to 75-80 DEG C for etherification reaction; and (4) after the etherification reaction is finished, neutralizing a product to the pH value of 7-7.5, and thereby obtaining the polyanionic cellulose with the ultrahigh viscosity for the water-based drilling fluid after washing, drying and crushing. The polyanionic cellulose prepared by the preparation method disclosed by the invention is ultrahigh in viscosity, low in production cost, and good in salt resistance, high in apparent viscosity and low in filter loss when being applied to water-based drilling fluid.

Description

technical field [0001] The invention relates to the technical field of polyanion cellulose production, in particular to a preparation method of ultra-high viscosity polyanion cellulose for water-based drilling fluid. Background technique [0002] Drilling fluid is divided into oil-based drilling fluid and water-based drilling fluid. With increasingly stringent environmental regulations around the world, water-based drilling fluids have become mainstream due to their low pollution. Cellulosic fluid loss control agents and rheology modifiers are rich in sources, biodegradable, and less polluting. The main products are sodium carboxymethylcellulose (CMC-Na) and polyanionic cellulose (PAC-Na). ). They are by far the largest, most widely used, and environmentally friendly drilling fluid fluid loss reducers and rheology modifiers. [0003] With the development of oil exploration to the subsea strata, the conditions for spud drilling are becoming more and more harsh, and the dri...

AI Technical Summary

Problems solved by technology

The shortcomings are: 1. Before alkalization, raw materials such as alkali and alcohol are not processed before entering the kneader, and they are only pre-mixed in the kneader for 10-30min for a short time, (longer time is also impossible , because the long-term residence of the reactants in this equipment will seriously affect the output of the entire production line), so, because the initial temperature is high, and the cellulose is an exothermic reaction due to alkaline cracking, the initial temperature of alkalization will be higher High, the initial temperature of alkalization is one of the key factors affecting the viscosity of the product, which will lead to a decrease in the viscosity of the final product; 2. The temperature during the entire alkalization period is also high, at 15-40 ° C, which greatly affects the high viscosity The product is obtained, the viscosity of the product is not high, and when it is used in water-based drilling fluid, it will lead to high filtration loss and poor salt resistance

3. The etherification agent still uses a single chloroacetic acid, which will inevitably lead to a large amount of alkali, and the heat of reaction during alkalization and etherification is relatively large, resulting in a large decrease in the viscosity of the product

PAC products prepared by slurry method obviously lack competitiveness in the market

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