POTENTIAL SEPIOLITE AS A SUBSTITUTE MATERIAL FOR DRILLING FLUID

In this study, rheological behavior of Sepiolite as a drilling fluid are investigated
and comparison study between rheological properties of Bentonite with Sepiolite has
been made to ensure optimum value of Sepiolite rheological properties. In high salt
contamination and high temperature well, the utilization of Bentonite mud system lead
to undesirable rheological performance. Hence, process of removing drilling cuttings is
disturbed; unacceptable fluid losses and optimum equivalent circulation density (ECD)
can not be achieved.
This research is focus on rheological properties of Sepiolite at vanous
temperatures and brine concentrations for instances at 150°F and 250°F of 16 hours hot
rolled. Semi saturated and saturated brine of 5 lb and 10 lb potassium chloride are
formulated in Sepiolite mud system. Furthermore, contradistinction analysis between
Bentonite and Sepiolite are analyzed to confirm the efficacious of Sepiolite
performance.
In order to design an effective drilling fluid system, fresh water is mixed with
potassium chloride to obtain a brine solution. Soda ash which is hardness material is
added in the solution and mixed for duration of 1 minute. Next, caustic soda is
circulated into the solution for about 5 minute. The function of this chemical is to adjust
pH value between 9.0 and 9.5. After that, HYDRO PAC-LV is added and mixed for 5
minutes followed by Bentonite. Last but not least, barite is added for 20 minutes as a
weighting agent.
In conclusion, Sepiolite mud system performs better than Sabah and India
Bentonite. Based on the pattern achieved from laboratory experiment, Sepiolite gives
best rheological values followed by Sabah Bentonite and India Bentonite. Nevertheless,
Sepiolite mud system exhibits highest fluid loss compare to the other Bentonite. This
situation can be treated by using higher performance of fluid loss reducer.