Abstract
The importance and awareness of accurate online water quality measurements increase every year in the oil and gas sector, whether it is for reducing oil discharge, preparing produced water for reinjection, or improving operational performance. For online measurement techniques to yield valuable analytical information, an understanding of their outputs must be established. Produced water reinjection has gained increasing attention in the last decade, as it can minimize negative environmental impacts by reducing oil discharge and has the potential to extend the economic life of reservoirs. To increase the amount of produced water that can be reinjected, the water must be maintained at a sufficient quality to prevent unintended formation damage. This review paper thoroughly describes different water quality issues related to suspended solids that can occur in an injection water treatment system and how the issues are often interlinked. A case study of measuring the total suspended solids concentration of seawater sampled from the Danish sector of the North Sea has been carried out to effectively quantify water quality in an injection water treatment facility. Furthermore, numerous on- and in-line techniques have been evaluated as candidates for measuring suspended solids. The last part of the paper discusses considerations regarding future microscopy analyzers based on five promising online microscopy technologies.