Electrical Stability Trend of Invert Oil Based Mud Pre-Mix Formulated with Synthetic Oil and Palm Kernel Oil Blends

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E. O. Ohimor


This work is aimed at determining the Electrical Stability (ES) of various oilbased
mud (OBM) pre-mix formulated with 100% synthetic base oil (SBO),
100% crude palm kernel oil (CPKO), 100% refined palm kernel oil (RPKO),
blends of SBO & CKPO, and finally blends of SBO & RPKO. An oil-based
mud pre-mix is a preliminary mud, prepared in the blending plant or factory,
without the addition of weighting materials, such as barite and some other
additives. The OBM pre-mix is conveyed to the rig or drilling site where
weighting material and other additives are incorporated and blended prior to
being used for the drilling operation. The electrical stability test, usually
carried out at a temperature of 49°C, is a very key test for determining
whether an OBM pre-mix is good or not. The higher the ES, the better the
OBM pre-mix. Thus, the ES tests were carried out on the various OBM premix
and the results showed that the OBM pre-mix formulated with SBO &
CPKO blends had relatively higher ES values than those formulated with
SBO & RPKO blends. Also worthy of note, is the fact that the OBM pre-mix
formulated with 40% SBO & 60% CPKO blend gave the highest ES reading
of 954 volts. A possible reason why the CPKO blends has better ES values
than the RPKO blends is the presence of high saturation of fatty acid, whereas
the RPKO has the fatty acids removed in the process of refining. The study
therefore implies that the 40% SBO & 60% CPKO blend could be a possible
substitute for the conventional 100% SBO in the preparation or formulation
of an environmentally friendly OBM pre-mix.

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