This book provides operators with the proper workflow systems and engineering techniques for designing, planning and implementing water injection systems that will improve recovery factors. When used in low permeability or ultra-low permeability reservoirs, water injection is one of the most economical methods for ensuring maximum production rates. This book provides both theoretical analysis and practical cases for designing and evaluating water injection systems and understanding key production variables involved in making detailed predictions for oil and water producing rates, water injection rates, and recovery efficiency. This book clearly explains the characteristics of ultra-low permeability reservoirs and linear flow theories. These topics are then applied to design and implementation. Application cases of four oilfields are included to help develop concepts while illustrating the proper workflow for ensuring waterflooding performance analysis and optimisation.