An amphiphilic polymer as shale inhibitor in water-based drilling fluid

Abstract

Shale hydration inhibitor in water-based drilling fluids (WBDFs) is the key to solve the problem of shale wellbore instability during drilling. In this study, a new amphoteric polymer was studied as a shale inhibitor. The amphiphilic copolymer ADL was synthesized by using acrylamide (AM), diallyl dimethyl ammonium chloride (DMDAAC) and dodecyl acrylate (LA) as monomers, benzoyl peroxide as initiator and hexadecyl trimethyl ammonium bromide (CTAB) as an emulsifier in aqueous solution. Infrared spectra indicated that the target product was synthesized successfully. TGA showed that the copolymers had good temperature resistance and the decomposition temperature was 240°C. The performance of ADL was evaluated by linear expansion experiment, rolling recovery rate experiment. The inhibition mechanism of the ADL was analyzed by particle size distribution experiment, zeta potential experiment and contact angle experiment. The experimental results show that ADL can adsorb on the surface of shale to change its wettability and increase the repulsive force between shale particles, thus inhibiting the hydration of shale. Because of its excellent shale inhibition performance, ADL has a potential application prospect as a shale inhibitor in WBDF.