New chemistry for chromium-free bentonite drilling fluids stable at high temperature

摘要

The broad substitution of aqueous drilling fluids for oil-based muds will require that the performance limitations of current aqueous muds be overcome. The research described in this paper is focused on the most commonly-used aqueous drilling fluids, lignosulfonate (LSO_3)-dispersed bentonite muds, and addresses two important issues that restrict their wider use: their limited stability at elevated temperature, and their reliance on chromium-containing additives (Cr-LSO_3 and Cr-lignite) for control of their rheological properties.