Water Injection (WI) to improve oil recovery is a process which has been utilised for more than a century  and has significantly evolved over the years. A sizeable amount of conventional oil production can be attributed to WI. South East Asia (SEA) is a rich source of hydrocarbon resources; natural gas and petroleum from countries - Brunei, Vietnam, Indonesia and Malaysia. SEA is still left with a sizeable oil reserves, despite a large historical production over a century, resulting in a large number of matured oil fields. Of these numerous matured fields, Malaysia alone has 28 WI fields targeting over 35% of discovered Stock-tank Oil Initially in Place (STOIIP), but accounting for 55% of total production with reservoir recoveries ranging from 20% to 60%. Hence in the South Eastern Region as a whole, there is significant scope to improve recovery through production by WI optimisation and management. Additionally, there are several brownfields with the potential to increase recovery by adopting WI as an improved or secondary recovery mechanism.