Water treatment method for heavy oil production

A process for producing steam for downhole injection in the recovery of heavy oii, said process comprising:

• (a) providing an oil/water mixture gathered from oil/water collection wells;
• (b) substantially separating oil from said oil/water mixture to provide an oil product and an oil containing produced water;
• (c) de-oiling said oil containing produced water residue to at least partially provide an evaporator feedwater, said evaporator feedwater comprising water, dissolved gases, and dissolved solutes, said dissolved solutes comprising silica;
• (d) heating said evaporator feedwater to remove at least some of said dissolved gases;
• (e) injecting said evaporator feedwater into an evaporator, said evaporator having a plurality of heat transfer elements;
• (f) distributing said brine on a first surface of at least one of said plurality of heat transfer elements, concentrating said evaporator feedwater, and generating a steam vapor;
• (g) discharging at least some of said brine as an evaporator blowdown stream;
• (h) slightly compressing said steam vapor to produce a compressed steam vapor;
• (i) directing said compressed steam vapor to a second surface of at least one of said plurality of heat transfer elements to condense said compressed steam vapor and to form a distillate stream, said distillate stream having a volume of at least ninety five percent or more of said evaporator feedwater stream;
• (j) collecting said distillate stream;
• (k) introducing said distillate stream into a boiler, to produce
• (i) steam,
• (ii) a boiler blowdown stream which is five percent or less by volume of said treated water stream, said boiler blowdown stream comprising water and residual dissolved solids;
• (l) injecting said steam in an injection well to fluidize oil present in a selected geological formation, to produce an oil and water mixture;
• (m) gathering said oil/water mixture from a production well.