Stimuli-responsive/rheoreversible hydraulic fracturing fluids as a greener alternative to support geothermal and fossil energy production

Abstract

A reversible CO2-triggered volume expansion significantly lowers the fracture initiation pressure in highly impermeable igneous rock as compared to conventional fracturing fluids.

CO2-responsive polymeric materials: synthesis, self-assembly, and functional applications

“…29 These nanocapsules can be employed in the controlled release of organic substrates with the stimulation of CO 2 . 278 To address these issues, Jung et al developed a non-toxic CO 2 -switchable and rheoreversible fracturing polymer aqueous solution (a polyallylamine (PAA)-CO 2 fracturing fluid) that undergoes a reversible volume expansion and contraction upon addition and removal of CO 2 . Biopolymers.…”

“…6.7.5. 278 This system increases considerably the stress and creates fractures in highly impermeable igneous rock and in an enhanced geothermal reservoir (which is a confined environment). Chitin, the most abundant polysaccharide, is composed of a chain of b-(1 -4)-linked N-acetyl-D-glucosamine residues, and is naturally available in the exoskeletons of insects, crustaceans, and shellfish.…”

A guide to the selection of switchable functional groups for CO2-switchable compounds

“…[25][26][27] This reaction has been proposed as a switching mechanism for use in superheated water underground 28 but is not applicable to applications below the normal boiling point of water. The conversion of a primary amine to a dialkylurea by an uncatalyzed thermal reaction with CO 2 takes place at a reasonable rate at temperatures above ~180 ˚C.…”

Catalyst characterization in the presence of solvent: development of liquid phase structure–activity relationships

“…Recently, customized NMR rotors have been designed to withstand conditions as extreme as 523 K and 200 bar, making solid state NMR a robust technique for the in situ monitoring of reactions. 34 , 35 Additionally, solid state NMR with magic-angle spinning (MAS) is particularly well suited for differentiating substrates that are adsorbed versus those remaining in bulk solution. 6 This is because adsorbed species typically result in significant peak broadening due to the restricted mobility or heterogeneities in the adsorbed structures.…”