Oil-Based-Mud Formulation and Optimization Using Thevetia Peruviana Oil

Abstract The need to avoid environmental degradation caused by toxic chemicals during drilling fluid operations is one of the objectives of the oil and gas industry. In this work, a non-edible plant of Thevetia Peruviana oil was used as potential base oil for formulation of drilling mud because of its non-toxic and environmental friendly nature of the plant. Oil extraction from the Thevetia Peruviana seeds was done using soxhlet method of extraction with n-hexane as the solvent. The formulated oil-based mud was compared with the API standard based on the mud density, filter cake thickness, gel strength and filtration loss. Four rheological models were considered, namely: Bingham plastic model, Power law model, Herschel-Bulkley model and Robertson-Stiff model. The optimization process was performed with MATLAB program in order to select the rheological model that best describe the behavior of the mud. The results of this study show that the formulated oil-based mud exhibited a non-Newtonian fluid rheological behavior. The rheology test result showed that the gel strength (10 min.) had 9.5 (Ib/100ft2), filter loss had 4.3 (mil) in term of filter volume. The mud density had 7.34 (Ib/gal), electrical stability of 528.0 (150°F and filter cake thickness of 1mm. Optimization of the Thevetia Peruviana oil based mud showed that Herschel-Bulkley model has the best performance indicators with good R2 (0.994) and standard error (2.16).