The Next Generation of Regenerative Catalytic Breakers for Use in Alkaline and High-Temperature Fracturing Fluids

Abstract

Enzymes represent an attractive alternative to oxidative chemical breakers for several reasons. They are polymer specific, environmentally friendly, easy to handle, miscible, do not damage equipment and they are naturally regenerating catalytic breakers. Enzymes have been used with great success for many years as breakers in fracturing applications.However, traditional enzyme breakers derived from mesophilic sources have a tendency to unfold from their functional threedimensional conformation into an inactive form under high temperatures. Thermal unfolding of enzymes proceeds via a dynamic equilibrium between active and inactive states, which reduces the enzyme activity, prior to an irreversible unfolding step as the temperature increases.To maximize enzyme functionality, a new generation of polymer-specific, thermostable enzyme was developed.The gene coding for the new enzyme was obtained and codon optimized for production in a commercially available expression system. Additional genetic enhancements were made to increase the yield and stability of the enzyme and further lower production costs.

Post-fracturing treatments design to redress the damage caused by fracturing fluid polymers

“…The Oxidant-breakers' ability for breaking the polymer is limited by their stoichiometric reaction (Armstrong et al, 2010) and their incapacity to regenerate their chemical activity. Furthermore, the high temperature induced a rapid decomposition of the breakers into highly reactive free radicals (Kidd, 2001).…”

“…Moreover, enzymes have the ability to regenerate their catalytic activity, catalyzing the hydrolysis of the polymer continuously. However, the fact that the enzyme -after four hours of reaction did not continue catalyzing the hydrolysis of the polymerindicates that it was denaturized due to high temperature (Armstrong et al, 2010).…”

A review of fracturing fluid systems used for hydraulic fracturing of oil and gas wells

“…However, enzymes are very temperature and pH sensitive . Oxidizers, on the other hand, have negative impacts on equipment and the environment, and are used up during the reaction . Some attempts have been made to develop enzymes for high temperature applications.…”

“…29 Oxidizers, on the other hand, have negative impacts on equipment and the environment, and are used up during the reaction. 30 Some attempts have been made to develop enzymes for high temperature applications. Zhang et al 29 have reported a thermostable mannanase enzyme that belongs to the glucanase family, which was originally discovered in a hydrothermal vent sample.…”

Chlorophyll: A Naturally Occurring Green Polymer Breaker for Hydraulic Fracturing

“…Even before state and federal agencies began to focus on the environmental impacts of shale development, responsible service providers were developing new fluids and technologies to minimize environmental, health, and safety risks of hydraulic fracturing operations. For example, biotechnology research enables the replacement of conventional oxidative breakers with polymer-specific enzyme technology that breaks the viscosity of polymers used in hydraulic fracturing applications (Armstrong et al, 2010). Enzyme breakers improve performance because of their inherent substrate specificity and their potential to degrade polymers infinitely.…”