Coated and cured proppants

Substantially cured, coated, discrete, proppants comprising solid proppant core particles, each with an outer surface that is substantially covered with a substantially cured, substantially homogeneous polyurethane coating that comprises the polyurethane reaction product of an isocyanate component and a polyol reactant that comprises castor oil, said coated and substantially cured proppant solids exhibiting an average particle size within the range from about 50 μm to about 3000 μm.

Cured, coated, 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, said coated and substantially cured proppant solids exhibiting an average particle size within the range from about 50 μm to about 3000 μm, wherein the core particles are coated with an adhesion agent that improves affinity of the polyurethane coating for the outer surface of said proppant core particle, wherein said polyurethane coating was made with an excess amount of isocyanate relative to said polyol reactant, and wherein the coated proppant exhibits sufficient resistance to flowback and sufficiently high crush resistance to maintain conductivity when placed in a subterranean fracture.