Patent ID: 6733636
Filing Date: 2004-05-11
Classification: C02F,E21B,Y10S

Abstract:
A method of producing steam for downhole injection in the recovery of heavy oil, said method comprising:(a) providing an oil and water mixture gathered from an oil and water collection well; (b) substantially separating oil from said oil and water mixture to produce (i) an oil product, and (ii) produced water having residual oil therein; (c) de-oiling said produced water to at least partially provide an evaporator feedwater, said evaporator feedwater comprising water, dissolved solutes, and dissolved gases, said dissolved solutes comprising silica; (d) heating said evaporator feedwater to remove at least some of said dissolved gases; (e) injecting said heated evaporator feedwater into a circulating concentrated brine in an evaporator; said evaporator having a plurality of heat transfer surfaces; (f) raising the pH of said concentrated brine to maintain solubility of silica in said concentrated brine; (g) distributing said concentrated brine on a first surface of at least one of said plurality of heat transfer surfaces to generate a steam vapor and further concentrating said circulating concentrated brine; (h) discharging at least some of said concentrated brine as an evaporator blowdown stream; (i) compressing said steam vapor to produce a compressed steam vapor; (j) directing said compressed steam vapor to a second surface of at least one of said plurality of heat transfer surfaces to condense said compressed steam vapor to form a distillate having residual solutes therein; (k) collecting said distillate; (l) removing said residual solutes from said distillate via electrodeionization treatment or via ion exchange treatment to produce (a) a substantially solute free distillate stream and (b) a solute containing reject stream; (m) introducing said distillate stream into a boiler, to produce (i) steam, (ii) a boiler blowdown stream, said boiler blowdown stream comprising water and residual dissolved solids, (iii) adding said boiler blowdown stream to said evaporator feedwater prior to the step of heating said evaporator feedwater.