A laboratory investigation has been done on durian rind, a fibrous material, as an alternative lost
circulation material in water-based mud. The experimental works covered the rheological properties and
lost circulation tests which were conducted before and after the hot-rolling tests as per API RP 13B.
Those tests involved the use of standard mud testing equipment and a lost circulation test cell. The
optimum concentration of the durian rind―which had been cleaned, cut into small pieces, dried in an
oven at 60°C for 24 hours, and ground into small fine particles―was determined before a performance
comparison study was done on both Hydro-plug (i.e., a commercial lost circulation material) and durian
rind of different sizes, namely fine (0.5 mm), medium (1.0 mm), and coarse (2.0 mm). The experimental
results showed that the durian rind worked well in combating the lost circulation. At its optimum
concentration of 20 lb/bbl, the coarse durian rind was found to have performed excellently in combating
lost circulation in 1 mm and 2 mm fractures. The standard rheological test showed that the rheological
properties of drilling fluid were not too affected at standard temperature of 75°F but they changed
significantly after the hot-rolling tests. The change in rheological properties was due to the flocculation
of bentonite and chemical reaction of the pectin in durian rind.