High temperature resistant and compound salt resistant viscosity reduction agent for drilling fluid and preparation method thereof

Abstract

The invention discloses a high temperature resistant and compound salt resistant viscosity reduction agent for a drilling fluid and a preparation method thereof. Modified lignin and an acrylic monomer are subjected to copolymerization, sulfonation, oxidation and complexation reactions to obtain a product. In a high temperature deep drilling process, the colloidal stability of the high-density and high-solid drilling fluid can be obviously improved, the rheology of the drilling fluid is improved, the used amount is few, the cost is low, the duration for the drilling fluid is long, the maintenance workload is few, and the viscosity reduction agent is innoxious and non-polluting, and can be innoxiously decomposed in an natural environment.

Description

technical field [0001] The invention relates to a high temperature and anti-compound salt viscosity reducer for drilling fluid and a preparation method thereof. Background technique [0002] Deep well high-density water-based drilling fluids tend to thicken, gel, or even solidify under high-temperature wellbore conditions, resulting in out-of-control rheological properties of drilling fluids and severely restricting safe, high-quality, and efficient drilling in deep wells. The main reason for the high-temperature thickening of water-based drilling fluid is that the high-temperature degradation of the drilling fluid treatment agent and the high-temperature dehydration of the clay particles lead to a decrease in the colloidal stability of the clay particles, resulting in flocculation or coalescence of the clay particles; in addition, when the drilling fluid encounters In saline layer, salt rock layer and salt gypsum layer, inorganic electrolytes such as salt and calcium invade...

AI Technical Summary

Problems solved by technology

[0018] According to the characteristics and application effects of the existing viscosity reducers, the natural viscosity reducers have outstanding viscosity reduction ability, but their high temperature resistance, salt resistance and calcium resistance are limited; the molecular structure of artificially synthesized viscosity reducers can be designed and Adjustment, through the selection of monomers and the optimization of the synthesis process, a viscosity reducer that meets high temperature resistance, salt resistance, and environmental safety can be prepared, but the price is high, and the high temperature resistance performance is not very outstanding.

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