Hydrocarbons recovery

Abstract

Methods and systems of separating a hydrocarbon phase from a mixture comprising an emulsion of water and hydrocarbons in the presence of a surfactant, comprising adjusting the salinity of the mixture to release hydrocarbons and water from the emulsion into a hydrocarbon phase and a salt-containing aqueous phase respectively; and separating at least a part of the hydrocarbon phase from the salt-containing aqueous phase wherein at least a part of the salt-containing aqueous phase is recovered for further use.

1 . A method of separating a hydrocarbon phase from a mixture comprising an emulsion of water and hydrocarbons in the presence of a surfactant, the method comprising:
 adjusting the salinity of the mixture to release hydrocarbons and water from the emulsion into a hydrocarbon phase and a salt-containing aqueous phase respectively; and   separating at least a part of the hydrocarbon phase from the salt-containing aqueous phase,   wherein at least a part of the salt-containing aqueous phase is recovered for further use.   
     
     
         2 . A method according to  claim 1 , further comprising reusing at least a part of the salt-containing aqueous phase to adjust the salinity of the mixture. 
     
     
         3 . A method according to  claim 1 , wherein the salinity of the mixture is adjusted by increasing the salinity of the mixture. 
     
     
         4 . A method according to  claim 1  further comprising desalinating the salt-containing aqueous phase to provide a first stream having a relatively high salinity and a second stream having a relatively low salinity. 
     
     
         5 . A method according to  claim 4  further comprising reusing the high salinity stream to increase the salinity of the mixture. 
     
     
         6 . A method according to  claim 4  further comprising reusing the low salinity stream to wash the hydrocarbon phase to recover surfactant. 
     
     
         7 . A hydrocarbons separation system comprising:
 an inlet for introducing a mixture comprising an emulsion of water and hydrocarbons in the presence of a surfactant;   a salinity adjustment station for adjusting the salinity of the mixture;   separating means for separating from the mixture a hydrocarbon phase and a salt-containing aqueous phase; and   recovery means for recovering at least a part of the salt-containing aqueous phase for further use.   
     
     
         8 . A system according to  claim 7  wherein the recovery means comprises a conduit for recycling at least a part of the salt-containing aqueous phase to the salinity adjustment station to adjust the salinity of the mixture. 
     
     
         9 . A system according to  claim 7  comprising a membrane for separating the hydrocarbon phase from the aqueous phase. 
     
     
         10 . A system according to  claim 9 , wherein the membrane acts as the separating means, either alone or in combination with a phase separation vessel. 
     
     
         11 . A system according to any one of  claim 7 , further comprising desalination means for desalinating the salt-containing aqueous phase to provide a first stream with a relatively high salinity and a second stream with a relatively low salinity. 
     
     
         12 . A system according to  claim 11 , wherein the desalination means comprises a reverse osmosis unit, a nanofiltration unit, or a nanofiltration unit upstream of a reverse osmosis unit. 
     
     
         13 . A system according to  claim 11  further comprising washing means for washing the hydrocarbon phase and recovering a surfactant recycle stream, and a conduit for channelling the second, low salinity stream to the washing means. 
     
     
         14 . A chemical enhanced oil recovery process comprising injecting surfactant recovered by the method of  claim 5  into a hydrocarbon-bearing formation. 
     
     
         15 . A chemical oil recovery process according to  claim 14  wherein the surfactant is combined with salt from the high salinity stream.