Potential Evaluation and Optimization of Natural Biopolymers in Water-Based Drilling Mud

Abstract

Drilling cost optimization has always been an important issue in the petroleum industry. In order to save costs and create new markets for local materials, Ofo (D. micocarpum) and food gum (C. populnea) powders were evaluated in this study at high temperature as alternative to imported chemical additives in water based drilling fluid. The base mud composed of alkali beneficiated local clay, achi (B. eurycoma), corn and cocoanut fibers whose viscosity, yield point and gel strength fell short the recommended API standard from preliminary analysis. The two factors were combined using experimental design technique and mud properties optimized numerically using desirability function. At optimum conditions, the mud’s properties obtained include: Plastic viscosity, PV (18.4 ± 0.63 cp), Yield point, Yp (15.7 ± 0.9 lbf/100ft2), Fluid loss, FL (12.1 ± 0.37 ml) and 10 min Gel strength (5.6 ± 0.05 lbf/100ft2). These values are in good agreement with the API recommended standard. Both biopolymers exhibited high potential at low and moderate temperatures. However, food gum is thermally stable, a good rheology stabilizer and filtrate reducer up to the test temperature of 185 oF. The presence and nature of salts in solution influences differently the viscosity of the two bio-polymers.