Tannin-Based Deflocculants in High Temperature High Pressure Wells: A Comprehensive Review

Clay deflocculants that are commonly used in water-based muds under high temperature pressure (HTHP) oilwell drilling conditions have been found to contain chromium which is toxic. Tannin-based regarded as a more environmentally friendly and suitable alternative the chrome-based deflocculants. However, tannin-based not studied extensively understood completely, for past two years, there many active pieces of research area. To advance area, need critically holistically review works done so far on mud additives identify challenges opportunities. This paper provides an overview HTHP conditions, including various forms, thermal stability, deflocculating ability environmental acceptance deflocculant. The revealed modified unmodified both deflocculate water well thermostable. only few studies conducted their usage at temperatures 150ºC or above. gaps identified if pursued could use green substitutes conventional