Low eutectic shale inhibitor, and preparation method and application thereof

Abstract

The invention relates to the field of well-drilling fluid inhibitors, and in particular, relates to a low eutectic shale inhibitor, and a preparation method and an application thereof. The low eutectic shale inhibitor is prepared by stirring and heating choline chloride and urea in an 80-100 DEG C oil bath for 2-4 h until the reaction mixture is a transparent liquid. Compared with other common inorganic salts, polymers and polyamine inhibitors in the market, the low eutectic shale inhibitor has cheap raw materials, is simple to synthesize, is environmentally friendly and non-toxic, has remarkable effects in inhibiting mud making in shale, shale expansion and shale dispersion, still has excellent inhibiting performance under a condition of high temperature, and has potential market value.

Description

technical field [0001] The invention relates to the field of drilling fluid inhibitors, in particular to a eutectic shale inhibitor. Background technique [0002] Borehole wall instability is the most serious problem in the oil and gas drilling process. When drilling into mud shale formations during drilling, the hydration expansion and dispersion of mud shale will lead to diameter shrinkage, collapse and sticking, mud bag bit, and A series of problems such as the difficulty of wellbore purification. Shale formations account for about 75% of formations encountered during drilling, and 90% of wellbore instability occurs in shale formations. The mechanical and physicochemical interactions between drilling fluid and shale formation are the main causes of wellbore instability. Oil-based and synthetic-based drilling fluids are the first choice to ensure safe and smooth drilling due to their excellent properties such as strong inhibition, lubricity, high temperature stability, a...

AI Technical Summary

Problems solved by technology

Potassium chloride is the earliest and most widely used shale inhibitor, but its dosage is generally relatively large, usually with a mass fraction of 2%-7%, which will affect the rheology and fluid loss of the drilling fluid. Concentrations of chloride ions also have adverse effects on the environment

Cationic polymers can effectively reduce the hydration swelling of clay, but the compatibility between cationic polymers and other additives in drilling fluids is poor, and the temperature resistance of polymers is also poor. A disclosed Chinese patent document CN103917623A A kind of hyperbranched polylysine has poor high temperature resistance

The effect of amine inhibitors is good, but the existing amine inhibitors, such as the polyamine shale inhibitors published in patent CN104592955A and CN103087691A, generally have a great influence on the rheology of drilling fluid, the amount of addition is difficult to control, and the biological toxicity is high. question

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