Inhibition Comparison between Polyether Diamine and Quaternary Ammonium Salt as Shale Inhibitor in Water-based Drilling Fluid

Increasingly, polyether diamine has been extensively used as a shale hydration inhibitor with splendid performance. In this article, a series of evaluation methods, including a bentonite inhibition test and tertiary cutting rolled dispersion test, were conducted to compare inhibition diversity between quaternary ammonium salt NW-1 and polyether diamine. Also, the compatibility with bentonite and several anionic and amphoteric additives was investigated. Results indicate that polyether diamine exhibits superior clay stabilization to NW-1 and provides a more permanent effect. Contrary to NW-1, polyether diamine is compatible with most conventional additives and bentonite, which alleviate the compatibility problems of cationic fluid systems. Furthermore, the novel amine is environmentally accepted and evaluated by toxicity test.