A method of recovering hydrocarbons from a porous subterranean
hydrocarbon-bearing formation comprising: (a) feeding a first stream
comprising a high salinity water to a first side of a semipermeable
membrane of at least one forward osmosis unit of a desalination plant and
feeding a second stream comprising an aqueous solution of a removable
solute to a second side of the semipermeable membrane wherein the solute
concentration of the aqueous solution of the removable solute is
sufficiently greater than the solute concentration of the high salinity
water that water passes through the semipermeable membrane from the high
salinity water into the aqueous solution of the removable solute to form
a diluted aqueous solution of the removable solute; (b) withdrawing a
third stream comprising a concentrated brine and a fourth stream
comprising a diluted aqueous solution of the removable solute from the
first and second sides respectively of the semipermeable membrane of the
forward osmosis unit; (c) substantially separating the removable solute
from the fourth stream comprising the diluted aqueous solution of the
removable solute to form a low salinity water stream having a total
dissolved solids content of less than 5000 ppm; (d) if necessary,
increasing the salinity of the low salinity water stream to a total
dissolved solids content of at least 200 @ @ m; (e) introducing the
treated low salinity water into the hydrocarbon-bearing formation via an
injection well; (f) displacing the hydrocarbons with the treated low
salinity water towards an associated production well; and (g) recovering
hydrocarbons from the formation via the production well.