Characterization of Commercial Amylases for the Removal of Filter Cake on Petroleum Wells

Abstract

Drilling fluid has many functions, such as carry cuttings from the hole permitting their separation at the surface, cool and clean the bit, reduce friction between the drill pipe and wellbore, maintain the stability of the wellbore, and prevent the inflow of fluids from the wellbore and form a thin, low-permeable filter cake. Filter cake removal is an important step concerning both production and injection in wells, mainly concerning horizontal completion. The drilling fluids are typically comprised of starch, the most important component of the filter cake. A common approach to remove this filter cake is the use of acid solutions. However, these are non-specific reactants. A possible alternative is the use of enzymatic preparations, like amylases, that are able to hydrolyze starch. Wells usually operate in drastic conditions for enzymatic preparations, such as high temperature, high salt concentration, and high pressure. Thus, the main objective of this work was to characterize four enzymatic preparations for filter cake removal under open hole conditions. The results showed that high salt concentrations (204,000 ppm NaCl) in completion fluid decreased amylolytic activity. All enzymatic preparations were able to catalyze starch hydrolysis at all temperatures tested (30, 65, 80, and 95 degrees C). An increase of amylolytic activity was observed with the increase of pressure (100, 500 and 1,000 psi) for one commercial amylase.

Marine Extremophiles: A Source of Hydrolases for Biotechnological Applications

“…Amylases are also used in the food industry for the production of glucose syrups, fructose and maltose, reduced viscosity of syrups, reducing the turbidity of juices and also for alcohol fermentation. They are also involved in the textile, papermaking, detergent, chemical, pharmaceutical and petroleum industries [ 5 , 160 , 161 ].…”

Nanobiocatalyst Based on Enzyme Immobilization for Mudcake Removal and Reservoir Damage Control

“…9 The first application of enzymes in petroleum engineering was reported in 1984, 10 and since enzymes have achieved a certain promotion in the removal of mudcake from drilling and completion fluids, degradation of oilfield polymers, treatment of wastewater, and EOR. 11 The high catalytic activity and specificity of the enzyme stems from its 3D conformation of the polypeptide chain, and the only drawback of this structure is that it is affected by the complexity of the environment (temperature, pH, etc.). 12 Moore et al of starch polymers on the well wall to mudcake removal.…”

“…Compared to other chemical catalysts, enzymes have higher catalytic activity, are more environmentally friendly, and have more precise chemical reaction selectivity and specificity . The first application of enzymes in petroleum engineering was reported in 1984, and since enzymes have achieved a certain promotion in the removal of mudcake from drilling and completion fluids, degradation of oilfield polymers, treatment of wastewater, and EOR . The high catalytic activity and specificity of the enzyme stems from its 3D conformation of the polypeptide chain, and the only drawback of this structure is that it is affected by the complexity of the environment (temperature, pH, etc.)…”