Polyelectrolyte complex nanoparticles to entrap enzymes for hydraulic fracturing fluid cleanup
Conference Paper
Overview
Overview
abstract
Guar-based polymer gels are used in the oil and gas industry to viscosify fluids used in hydraulic fracturing of hydrocarbon production wells. After fracturing, the gel and filter cake must be degraded to obtain high hydraulic conductivity of the fracture and rock/fracture interface. Enzymes are widely used to achieve this but high concentrations may result in premature degradation or failure to gel; denaturation of enzymes at harsh pH and temperatures also limits their applicability. Polyethylenimine-dextran sulfate polyelectrolyte complexes were used to entrap two guar-degrading enzymes to obtain delayed release and to protect the enzyme from harsh conditions. Degradation, as revealed by viscoelastic properties, of borate-crosslinked hydroxypropyl guar gel by commercial enzyme loaded in polyelectrolyte nanoparticles was delayed up to 11 hours, compared to about three hours for equivalent systems where the enzyme mixture was not entrapped. PEC nanoparticles also protected both enzymes from denaturation at elevated temperature and pH.
