Development of self-generated proppant based on modified low-density and low-viscosity epoxy resin and its evaluation

Hydraulic fracturing is a critical technology for the economic development of unconventional oil and gas reservoirs. The main factor influencing fracture propping and reservoir stimulation effect is proppant performance. The increasing depth of fractured oil and gas reservoirs is causing growing difficulty in hydraulic fracturing. Moreover, the migration of conventional proppants within the fracture is always limited due to small fracture width and rigid proppant structure. Thus, proppants with good transportation capacity and fracture propping effects are needed. First, a novel self-generated proppant based on toughened low-viscosity and low-density epoxy resin was developed to satisfy this demand. Then, proppant performances were evaluated. Low-viscosity and low-density epoxy resin was generated when the thiol-ene click chemical reaction product of eugenol and 1-thioglycerol reacts with the epichlorohydrin. Then, the resin was toughened with graphite particles to increase its compressive strength from 50.8 to 72.1 MPa based on micro-cracking mechanism and crazing-nail anchor mechanism. The adduct of diethylene triamine and butyl glycidyl ether and the SiO2 nanoparticles were treated as the curing agent and emulsifier respectively to form the emulsion. The emulsion is transformed into solid particles of various sizes within a reservoir to prop the fracture. Evaluation shows good migration capacity of this self-generated proppant due to the low density of epoxy resin.