Abstract:
This study carried out to assess the effect of increasing bentonite percentage (solid
phase) on rheological properties and filtration loss for water base drilling fluid prepared from
local bentonite (Umm Ali area). Chemical tests were carried out to assess quality of local
bentonite. In this study Carboxymethyle Cellulose CMC is used to increase viscosity and
decrease filtration loss. The major finding showed that when adding 7% of CMC and 7% of local
bentonite, the rheological properties, filter loss and yield point to plastic viscosity ratio will be
within the acceptable range of American Petroleum Institute (API) specifications
