This book is important to the oil and gas industry and petroleum engineering field because sulphate scales are the most difficult profit hunting phenomena and their immense impact on productivity if left untreated creates serious arching in the oil and gas industry operation. It reduces the productivity of the well by blocking the flow paths of the various oil and gas equipment along water paths, including but not limited to piping, injectors, reservoirs, and surface facilities. Scale formation may eventually leads to low production and equipment failure. Sulphate scales are recognized as one of the top production problems in regions that are prone to scales, such as the North Sea, Saudi Arabic, UAE, the US, and Canada. The derivations in this book could be introduced to compliment most of the existing oilfield scales predictive software like ScaleChem and multiSCALE 6.1 to account for effect of key operational and reservoir parameters on the magnitude of impairment by scale deposition around wellbore. The newly developed models in this book are useful for operators to refine their procedures and better manage the risk of flow assurance problems induced by sulphate scale.