Formulation of Drilling Fluids for High Temperature Well Application Using Sabah Bentonite

Abstract

The objective of this work was to investigate the rheological performance of a locally-sourced bentonite from Sabah for use as drilling fluid and compare it to a commercial bentonite from India. The rheological properties of the drilling fluids were obtained using standard testing apparatus such as mud balance, viscometer and filter press. It was observed that the Sabah bentonite has lower values of density, gel strength (GS), plastic viscosity (PV), yield point (YP) and filtration loss as compared to the Indian bentonite. The Malaysian bentonite did not meet the API required viscometer reading of 600 rpm. However, it was found that adding 1.0 ppb of NaOH as an additive to the mud improves the rheological performances of the mud significantly to meet the API standard. Economic analysis indicates that the treated Sabah bentonite mud is cheaper than the Indian bentonite by as much as 39%. The results of this work showed that the locally-sourced treated bentonite is technically and economically feasible for use as a drilling fluid.