Patent ID: 7731843

Claim:
A method for treatment of untreated injection water for a subsea injection well, said injection water being one of: (A) water from a body of water overlying the injection well, and (B) produced water from a well production stream; said method comprising: lowering a water treatment apparatus and a water injection pumping equipment connected thereto into said body of water overlying the subsea injection well, said water treatment apparatus comprising at least one module provided with at least one receptacle and an associated network of lines with valves for allowing flow of injection water through said receptacle and line network during water injection into subsea well, and said at least on receptacle being provided with at least one type of water-soluble, solid state chemical; connecting the water treatment apparatus and the water injection pumping equipment to the subsea injection well; bringing said water into contact with the at least one solid-state chemical within the at least one receptacle, thereby causing said solid-state chemical to gradually dissolve and mix with the contacting water, treated water thus emanating from said receptacle; and leading the treated water into an injection stream conveyed into the injection well and further into an associated reservoir.