Abstract
Conventional scale inhibitor squeezes are widely used to prevent or delay scale formation. Although long established the process can be wasteful of chemical used. In common with the use of most production chemicals such treatments are ‘once through’ and non-recoverable with high operating costs. In addition in offshore operations such production chemicals are discharged into the sea. Such discharges are also subject to environmental legislation with associated costs. Increasingly there is a need to avoid such discharges. Modifications of the squeeze procedure have been introduced to extend squeeze lifetime but further improvements are still sought. This paper describes the results of a study to investigate the potential for membrane separation to capture a representative scale inhibitor from brine. Over a range of temperatures, scale inhibitor concentrations and brine chemistries more than 96% of the scale inhibitor was captured. This was obtained without any attempt to optimise operating conditions. The resulting captured material was compared to the original product using dynamic tube blocking tests and static barium sulphate tests. The static tests showed similar performance for recovered and initial material, while the dynamic tests showed a marginal increase in performance for the recovered material in some cases. This increase in performance correlates with the retention factor for each given test run. It is believed that this is due to a slight purification of the inhibitor during the separation process, as shown by Dionex Ion Chromatography. The effective performance of the recovered inhibitor suggests that it could be re-used in a similar manner to the original product.
