This work evaluates the effect of dividivi tannins (Caesalpinia coriaria) in its unmodified form in the rheological properties of standard water-based drilling fluids contaminated with gypsum (CaSO4) and its comparison with commercial tannin (reference). The plastic viscosity, yield point and gel strength of water-based drilling fluids contaminated with 5 lb/bbl gypsum was studied. The dividivi tannins contain 67.40% of hydrolyzable tannins (decomposable in water, with which they react to form other substances). The performance of dividivi tannins as deflocculant agent in water-based drilling fluids contaminated with gypsum, before and after aging, was improved, compared with commercial tannin (reference tannin). Dividivi tannins in water-based drilling fluid with gypsum achieved deflocculant efficiency of nine (9) times more than commercial tannin. On the other hand, the commercial tannin, does not improves its deflocculant efficiency with increase tannin content and temperature in water-based drilling fluids contaminated with gypsum; but shows a trend to remain constant behavior.

Keywords:
drilling fluid chemistry, drilling fluid formulation, water-based drilling fluid, suspension, deflocculant agent, drilling fluid selection and formulation, Upstream Oil & Gas, WBDF, dividivi tannin, drilling fluid property
Subjects:
Drilling Fluids and Materials, Drilling fluid selection and formulation (chemistry, properties)
Copyright 2015, Society of Petroleum Engineers
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