Produced water can be routely re-injected into reservoir for purposes including pressure support and environmentally acceptable disposal. Scale prevention and control is required to maintain well injectivity and longetivity. This paper presents a comprehensive scale study to reliably access injection well scaling potential and establish fit-for-purpose/optimal scale management strategy. Field water samples were appropriately collected and characterized. Laboratory testing was well designed/conducted to understand scale formation potential, and determine required scale inhibitor dosage. Study results suggest calcite and silicate scales can be of potential concern, and increase of downhole temperature or/and fluid residence time (e.g., under abnormal operation condition with low injection rate or well shut in) at near wellbore formation can lead to higher scaling risk. Testing results show that one scale inhibitor product (originally recommended by chemical vendor) at high dosage can potentially accelerate scale formation leading to more solid precipitation. Alternative inhibitor products were tested and scale inhibitor selection and treatment strategy was optimized based on testing results.