A method for desalting produced hydrocarbons

Abstract

A method for desalting produced hydrocarbons includes injecting reduced-salinity water into produced hydrocarbons in a production well or riser, to dilute high-salinity produced water contained in the produced hydrocarbons.

1 . A method for desalting produced hydrocarbons, the method comprising:
 injecting reduced-salinity water into produced hydrocarbons in a production well or riser, to dilute high-salinity produced water contained in the produced hydrocarbons.   
     
     
         2 . The method of  claim 1 , wherein the reduced-salinity water has a salinity lower than seawater in a body of water above a field in which the production well is located, and/or has a salinity lower than the high-salinity produced water. 
     
     
         3 . The method of  claim 1 , wherein the reduced-salinity water has a salinity of less than 60 000 mg/L, preferably less than 55 000 mg/L, more preferably less than 40 000 mg/L, and still more preferably less than 31 000 mg/L. 
     
     
         4 . The method of  claim 1 , wherein the reduced-salinity water is injected into the produced hydrocarbons through one or more openings in production tubing located in the production well, or one or more openings in the riser. 
     
     
         5 . The method of  claim 4 , wherein the one or more openings in the production tubing or production riser are provided with valves to control the inflow of reduced-salinity water. 
     
     
         6 . The method of  claim 1 , wherein the produced hydrocarbons are contained in production tubing located in the production well, wherein the reduced-salinity water is injected deep in the production well such that injection takes place close to a lower completion section. 
     
     
         7 . The method of  claim 1 , wherein the reduced-salinity water is injected in an amount sufficient to create an oil-in-water emulsion in which the produced hydrocarbons are suspended as a dispersed phase within a continuous phase provided by the reduced-salinity water. 
     
     
         8 . The method of  claim 1 , wherein the reduced-salinity water is injected in an amount sufficient to create a water-in-oil emulsion in which the reduced-salinity water is suspended as a dispersed phase within a continuous phase provided by the produced hydrocarbons. 
     
     
         9 . The method of  claim 1 , wherein the reduced-salinity water is configured to provide a mixing efficiency of greater than 50%, preferably greater than 60%, and still more preferably greater than 75%, with the produced hydrocarbons. 
     
     
         10 . The method of  claim 1 , wherein the reduced-salinity water has a higher temperature than fluids in a reservoir from which the produced hydrocarbons are produced. 
     
     
         11 . The method of  claim 1 , wherein the reduced-salinity water is injected into the produced hydrocarbons in combination with gas. 
     
     
         12 . The method of  claim 11 , wherein the reduced-salinity water and the gas are injected simultaneously into the produced hydrocarbons in the production well.