A composition comprising a plurality of particulates for being flowed, under the influence of hydraulic pressure, from a downhole fracking position inside a subterranean well structure through openings in the well structure into fractures and cracks in an adjacent subterranean formation to aid in a fracking process for enhancing the permeability of the formation through development of fractures or cracks therein, wherein: each of the particulates comprises at least one degradable polymer and a barrier coating applied over the degradable polymer; the degradable polymer comprises: from 20 to 80 mole percent monomer residues of a first monomer selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; from 20 to 80 mole percent monomer residues of a second monomer, which is different from the first monomer, selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; and from about 0.001 to about 32 mole percent monomer residues of at least one compound which is capable of reacting with either the first monomer or the second monomer to form an ester, such that the degradable polymer is solid when maintained under dry conditions at a temperature up to 90° C and, when maintained in contact with water in the well at the downhole fracking location at a formation temperature of from 44° C up to 82° C, commences gradual degradation by reason of hydrolysis to a highly viscous, flowable liquid, which is flowable under the influence of hydraulic pressure outwardly of the well structure, through the well structure openings and into cracks and fractures in the adjacent formation to transmit to the formation hydraulic pressure forces applied thereto, and to thereby induce cracking and fracturing in the formation and further flowing of the polymer into and through the cracks and fractures created in the formation; and the barrier coating comprises a crystalline wax-like hydrolytically degradable polymer material having a melting temperature that matches the bottom hole temperature, whereby continued hydrolysis of the polymer causes the polymer to completely degrade to water-soluble components after at least 3 days. each of the particulates comprises at least one degradable polymer and a barrier coating applied over the degradable polymer; the degradable polymer comprises: from 20 to 80 mole percent monomer residues of a first monomer selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; from 20 to 80 mole percent monomer residues of a second monomer, which is different from the first monomer, selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; and from about 0.001 to about 32 mole percent monomer residues of at least one compound which is capable of reacting with either the first monomer or the second monomer to form an ester, such that the degradable polymer is solid when maintained under dry conditions at a temperature up to 90° C and, when maintained in contact with water in the well at the downhole fracking location at a formation temperature of from 44° C up to 82° C, commences gradual degradation by reason of hydrolysis to a highly viscous, flowable liquid, which is flowable under the influence of hydraulic pressure outwardly of the well structure, through the well structure openings and into cracks and fractures in the adjacent formation to transmit to the formation hydraulic pressure forces applied thereto, and to thereby induce cracking and fracturing in the formation and further flowing of the polymer into and through the cracks and fractures created in the formation; and from 20 to 80 mole percent monomer residues of a first monomer selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; from 20 to 80 mole percent monomer residues of a second monomer, which is different from the first monomer, selected from the group consisting of L-lactic acid, D-lactic acid, L-lactide, D-lactide, and glycolic acid; and from about 0.001 to about 32 mole percent monomer residues of at least one compound which is capable of reacting with either the first monomer or the second monomer to form an ester, such that the degradable polymer is solid when maintained under dry conditions at a temperature up to 90° C and, when maintained in contact with water in the well at the downhole fracking location at a formation temperature of from 44° C up to 82° C, commences gradual degradation by reason of hydrolysis to a highly viscous, flowable liquid, which is flowable under the influence of hydraulic pressure outwardly of the well structure, through the well structure openings and into cracks and fractures in the adjacent formation to transmit to the formation hydraulic pressure forces applied thereto, and to thereby induce cracking and fracturing in the formation and further flowing of the polymer into and through the cracks and fractures created in the formation; and the barrier coating comprises a crystalline wax-like hydrolytically degradable polymer material having a melting temperature that matches the bottom hole temperature, whereby continued hydrolysis of the polymer causes the polymer to completely degrade to water-soluble components after at least 3 days.