High performance proppants
Embodiments disclosed herein provide coated particles that can be used, for example, in the extraction of oil and gas from subterranean formations.
1. A coated particle comprising:
a particle; and
a coating adhered to the particle, wherein the coating comprises:
a first layer comprising a silane coupling agent;
a second layer the first layer, wherein the second layer is a phenolic resin coating;
a third layer in contact with the second layer, wherein the third layer is a phenolic resin coating; and
a fourth layer in contact with the third layer, wherein the fourth layer is a polyurethane coating admixed with a surfactant,
wherein the fourth layer completely encapsulates the first, second, and third layers.
2. The coated particle of claim 1 , wherein the polyurethane coating is an outer layer.
3. The coated particle of claim 1 , wherein the particle is sand, silica, rocks, minerals, ceramic, bauxite, polymeric particles, or any combination thereof.
4. The coated particle of claim 1 , wherein the second and third layer has less than or equal to 0.5% wt free phenol.
5. The coated particle of claim 1 , wherein the coating comprises an additional phenolic resin layer encapsulated by the polyurethane.
6. The coated particle of claim 1 , wherein at least one of second and third layers is fully cured.
7. The coated particle of claim 1 , wherein one of the second layer and third layer is a fully cured phenolic resin coating and the other is a partially cured phenolic resin coating.
8. The coated particle of claim 1 , wherein the melting point of the phenolic resin layer is about 60° C. to about 130° C.
9. The coated particle of claim 1 , wherein the coated particle comprises the phenolic resin in an amount of about 0.5% to about 6.0% wt/wt.
10. The coated particle of claim 1 , wherein the coated particle leaches an amount of free phenol into a water sample that is less than or equal to 2.0 ppm.
11. The coated particle of claim 1 , wherein the coated particle comprises less than or equal to about 5% wt fillers.
12. A method of treating a subterranean formation penetrated by a wellbore comprising contacting the subterranean formation with a coated particle of claim 1 .
13. The coated particle of claim 1 , wherein the second layer phenolic resin coating is a phenol-aldehyde resin.
14. The coated particle of claim 1 , wherein the third layer phenolic resin coating is a phenol-aldehyde resin.
15. The coated particle of claim 1 , wherein the second, third, and fourth layer are substantially cured.
16. A plurality of particles consisting of the coated particles of claim 1 .
17. The coated particle of claim 1 wherein, wherein the third layer completely encapsulates the second layer.
18. The coated particle of claim 1 , wherein the second layer completely encapsulates the first layer.
19. The coated particle of claim 1 , wherein the third layer completely encapsulates the second layer and the second layer completely encapsulates the first layer.
20. A process for preparing the coated particles of claim 16 , the process comprising:
coating the particles with the silane coupling agent to produce the silane coupling agent coated particles;
coating the silane coupling agent coated particles with the phenolic resin coating to produce one layer phenolic resin coated particles;
coating the one layer phenolic resin coated particles with the phenolic resin coating to produce two layer phenolic resin coated particles; and
coating the two layer phenolic resin coated particles with the polyurethane coating admixed with the surfactant that completely encapsulates the two layer phenolic resin coated particles to produce the coated particles of claim 16 ,
wherein the phenolic resin layers have less than or equal to 0.5 wt % free phenol.