TITLE:
Tannin-Based Deflocculants in High Temperature High Pressure Wells: A Comprehensive Review
AUTHORS:
Michael Kwadwo Fokuo, Wilberforce Nkrumah Aggrey, Mizpah Ama Dziedzorm Rockson, Yen Adams Sokama-Neuyam, Patrick Boakye, Gershon Amenuvor, Kwame Sarkodie, Emmanuel Pinto, Hassan Karimaie
KEYWORDS:
Deflocculant, Tannin, Drilling Fluid, Bentonite, Flocculation, High Temperature
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.11 No.4,
October
19,
2021
ABSTRACT: Clay deflocculants that are
commonly used in water-based muds under high temperature
high pressure (HTHP) oilwell drilling conditions have been found to contain
chromium which is toxic. Tannin-based deflocculants are regarded as a more
environmentally friendly and suitable alternative to the chrome-based
deflocculants. However, tannin-based deflocculants have not been studied
extensively and understood completely, and for the past two years, there have
not been many active pieces of research in the area. To advance research in the
area, there is a need to critically and holistically review research works that
have been done so far on tannin-based deflocculants as drilling mud additives
to identify research challenges and opportunities. This review paper provides
an overview of tannin-based deflocculants used in water-based muds under HTHP
drilling conditions, including the various forms, thermal stability,
deflocculating ability and environmental acceptance of the deflocculant. The
review revealed that under HTHP conditions, modified and unmodified
tannin-based deflocculants both deflocculate water muds well and are
thermostable. However, only a few studies have been conducted on their usage as
deflocculants at temperatures of 150ºC or above. The research gaps identified if pursued could advance the use
of tannin-based deflocculants as green substitutes for the conventional
chrome-based deflocculants.