The use of α-amylase and pullulanase enzymes in wellbore cleaning

Abstract

The α-amylase and pullulanase enzyme treatment solutions were introduced to overcome the issue of formation damage. The laboratory procedures had been conducted under static condition at different temperatures ranging from 75°F to 250°F. The treatment process was performed using two types of concentration, namely by percentage of volume and by enzyme unit activity. Experimental results showed that the optimum degradation efficiency using concentration of enzyme by volume was at 6%, where α-amylase achieved 82% of degradation efficiency at 100°F and pullulanase gave 87% at 150°F. The optimum concentration using enzyme unit activity was at 150U/100 ml where both a-amylase and pullulanase achieved 68% of degradation efficiency at their respective optimum temperatures. Enzyme stabiliser and viscoelastic surfactant were introduced into the enzyme solutions in order to enhance the degradation efficiency of the enzymes beyond their optimum temperatures. The experimental results revealed that the addition of enzyme stabilizer had succeeded in improving the degradation efficiency for both α-amylase and pullulanase enzyme (i.e. 64% and 69% as compared to 58% and 66% at 200°F respectively) while the addition of viscoelastic surfactant had allowed α-amylase and pullulanase enzymes to experience an increase in degradation efficiency of 60% and 67% respectively as compared to 58% and 66% at temperature of 200°F respectively.