Research on Gel Breaking Process of Emulsion Associating Polymer Fracturing Fluid

Abstract

The associative polymer is a highly concentrated solution state in the emulsion droplets and does not need to undergo swelling in the water 10 seconds completely dissolved, as an instant-type fracturing fluid can be used for large-scale hydraulic fracturing. In this paper, the gel breaking process of this fracturing fluid is studied in detail, and it is found that ammonium persulfate can be completely hydrated in 40~120min. The surface tension is 27.5mN·m^-1 and the interfacial tension is 0.3mN·m^-1, which meets the requirement of back-flow. For results of research on gel-breaking mechanism, the electron atmosphere of the C-C bond in the polymers main chain is reduced by the electron absorption effect of side -chain carbonyl. The free radical attack produced by the peroxides is broken and the amide group undergoes three stages of hydrolysis to produce the carboxyl group.