Tight oil reservoirs need stimulation in order to produce the trapped oil. The most common form of stimulation used by the oil and gas industry is hydraulic fracturing. Fracturing operations tend to create fractures including primary fractures and microfractures. The objective of this study is to develop a fracturing fluid which can be converted into microproppant, beads, and channelized-proppant as desired in-situ during a fracturing operation to enhance the hydraulic conductivity of the microfractures and the primary fractures, and simplify the hydraulic fracturing operation, where the channelized-proppant is defined as the pillars surrounded by channels.
Resin, curing agents, surfactants, and aqueous phase were mixed together to form O/W emulsion to serve as fracturing fluid. After curing process, resin and curing agent would react and form proppant in-situ. The parameters affect the proppant formation such as the curing temperatures, pressure, mixing strength, surfactant concentration, and size control additives were all studied and thus through controlling the parameters, microproppant, beads, and channelized-proppant can form in-situ as desired. The particle size distribution, sphericity, roundness, conductivity, acid solubility, and crush strength were tested.
Through controlling the experimental parameters and adding size control additives, fracturing fluid can be converted into microproppant, beads, and channelized-proppant as desired at a temperature from 30° C to 90° C. Almost 100% of the resin and the curing agents were converted into proppant with a specific density of 1.09g/ml. For the beads, both the sphericity and roundness are over 0.9, less than 2% fines were generated after being loaded to 15 kpsi, the acid solubility is 2.37%, and the conductivity of the beads of 20/40 mesh tested with proppant loading of 1 lb/ft2 at 4000 psi at room temperature was 227 mD-ft. For the microproppant, both the sphericity and roundness are close to 1 with d50 about 80 µm. Furthermore, channelized-proppant was formed in an artificial fracture with walls made of glass sheets. Thus, with the fracturing fluid developed, the conductivity of the well can be maximally optimized through the in-situ formation of channelized proppant and microproppant to keep the primary fractures and microfractures open respectively.