A Review of Advanced Molecular Engineering Approaches to Enhance the Thermostability of Enzyme Breakers: From Prospective of Upstream Oil and Gas Industry

Abstract

During the fracture stimulation of oil and gas wells, fracturing fluids are used to create fractures and transport the proppant into the fractured reservoirs. The fracturing fluid viscosity is responsible for proppant suspension, the viscosity can be increased through the incorporation of guar polymer and cross-linkers. After the fracturing operation, the fluid viscosity is decreased by breakers for efficient oil and gas recovery. Different types of enzyme breakers have been engineered and employed to reduce the fracturing fluid′s viscosity, but thermal stability remains the major constraint for the use of enzymes. The latest enzyme engineering approaches such as direct evolution and rational design, have great potential to increase the enzyme breakers’ thermostability against high temperatures of reservoirs. In this review article, we have reviewed recently advanced enzyme molecular engineering technologies and how these strategies could be used to enhance the thermostability of enzyme breakers in the upstream oil and gas industry.

Review on High-Temperature-Resistant Viscoelastic Surfactant Fracturing Fluids: State-of-the-Art and Perspectives

“…Each fluid has its own advantages and disadvantages, which are shown in Table . At present, guar gum and its derivatives are still the most widely used thickeners, accounting for 90% of the hydraulic fracturing fluid market, due to their advantages such as strong thickening with low loading, good temperature resistance (up to 177 °C), and strong sand-carrying capacity. However, due to the slow swelling rate of guar gum, they are prone to microbial degradation, so it is necessary to add bactericides .…”

Enhanced Thermostability of Nattokinase by Computation-Based Rational Redesign of Flexible Regions

“…2 Molecular modification techniques, such as genetic and protein engineering, can effectively enhance enzyme thermostability. 4 It constructs a protein mutation library by introducing mutations at the nucleic acid level and then obtains target proteins with improved thermostability by screening. The common strategies for improving the thermostability of enzymes include directed evolution, rational design, and computer-aided design.…”

“…Molecular modification techniques, such as genetic and protein engineering, can effectively enhance enzyme thermostability . It constructs a protein mutation library by introducing mutations at the nucleic acid level and then obtains target proteins with improved thermostability by screening.…”