ANALYSIS ON CHARACTERISTIC OF SABAH BENTONITE AT IDGH TEMPERATURE UNDER DYNAMIC CONDffiON

This project is carried out to study the properties of Bentonite, particularly Sabah
Bentonite. A series of experiments, by mixing the two Bentonite are conducted and
comparing them to API specification, under dynamic condition, as to stimulate the
real drilling process to achieve a more accurate result. The rheology properties of the
drilling fluids, such as density, viscosity and yield point are obtained by conducting
experiments using few apparatus, such as mud balance and direct indicating
viscometer. The Fann 90 Dynamic Filtration Test Apparatus is used to get the
outcome of the study by comparing the parameters of dynamic filtration rate and
static filtration rate. The experiments are conducted first in Low Temperature (L T)
condition and the target composition, 55% Sabah Bentonite and 45% Indian
Bentonite is selected for the High Temperature (HT) condition. Sodium Hydroxide
(NaOH) is then added from 0.5 ppb to 4.0 ppb for further rheological and filtration
loss evaluation. The comparison of rheological properties of the three drilling fluids:
Indian, Sabah and Mixture. For Sabah and Mixture, as the temperature increases, the
clay swelling decreases, thus the PV, YP and GS of the mud decreases. For Indian, as
the temperature increases, it caused the bentonite to become more dispersed,
increasing the number of individual platelets in the suspension, thus PV, YP and GS
increases. For mixture of 45% Indian and 55% Sabah bentonite, the dynamic
filtration is higher than static condition at lower temperature but lower in high
temperature as they are no real correlation between static and dynamic condition.
Optimum of0.5 ppb ofNaOH added improved the rheological properties but not the
filtration properties. The economic analysis showed that treated Andrassy sample is
much cheaper than the commercial bentonite (60.71 % cheaper). This directly
increases the gross domestic product (GDP) of Malaysia and can beneficiated the
country. Further recommendations are suggested for next research.