Dow Global Technolgoies LLC

Praveen Agarwal

William J Harris

Rajat Duggal

Juan Carlos Medina

Arjun Raghuraman

Bindu Krishnan

Qiuyun Xu

Coated proppant particles are prepared by coating the particles with at least one polyisocyanate, and at least one urethane catalyst, and starch is present during at least part of the curing step. The starch becomes incorporated into in at least a portion of the cured coating. The coating cures rapidly at moderate temperatures, and bonds to itself well under conditions of heat and pressure as are experienced by the particles in subterranean formations.

Coated proppants

Coated proppant particles are prepared by coating the particles with a coating composition that includes at least one polyisocyanate and at least one ingredient selected from i) an isocyanate trimerization catalyst, ii) a carbodiimide catalyst, iii) an alcohol, iv) a polyamine and v) an alkanolamine, and curing the coating composition. Starch is present during at least part of the curing step, such that the starch becomes embedded in at least a portion of the cured coating. The coating composition cures rapidly at moderate temperatures, and bonds to itself well under conditions of heat and pressure as are experienced by the particles in subterranean formations.

A continuous process for forming a coated proppant, said process comprising the steps of: (a) washing particles, (b) drying the particles at a first predetermined temperature, (c) cooling the particles, (d) feeding the cooled particles with a second predetermined temperature lower than the first predetermined temperature to an inlet of a combined continuous mixer and conveyor unit, (e) feeding a coating composition into the combined continuous mixer and conveyor unit, (f) mixing and simultaneously conveying the particles and the coating composition for a predetermined time, (g) curing the coating composition by transfer of heat from the particles, (h) discharging the coated particles from an outlet of the combined continuous mixer and conveyor unit, wherein said process does not comprise a step of heating the particles after the drying.

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Lake Jackson, TX, United States of America

Praveen Agarwal