Coated and cured proppants

摘要

Solid proppants are coated with a phenol-urethane coating in one or more layers by a method comprising coating a proppant solid and then curing the coated proppant under conditions sufficient to substantially cure said proppant, wherein said coating comprises a substantially homogeneous mixture of (i) an isocyanate component having at least 2 isocyanate groups, (ii) an amine reactant, and optionally (iii) an amine that is a latent curing agent for said isocyanate.

主权项

1. Cured, coated, discrete, proppants comprising solid proppant core particles, each with an outer surface that is substantially covered with a cured, substantially homogeneous polyurethane coating that comprises the polyurethane reaction product of an isocyanate component and a polyol reactant that is selected from the group consisting of cashew nut oil, cardanol, cardol, a hydroxy-functional polyether, and castor oil, wherein said polyurethane reaction product was made with an excess of said isocyanate relative to said polyol and wherein said coated and cured proppant solids exhibit an average particle size within the range from about 50 μm to about 3000 μm and sufficient resistance to flowback and sufficiently high crush resistance to maintain conductivity when placed in a subterranean fracture.