Abstract
This paper reports further work performed on a challenging scaling environment in Alberta. Scale was forming on the fire tubes of a series of heater treaters. Bulk fluid temperature was 110°C but skin temperature of the fire tubes was in excess of 450°C. This created an incredibly high scaling potential.
Previous work characterized the scaling on the tubes. This is briefly summarized with an update given on the continued success of this treatment, best practice monitoring results, and optimization. This current work describes the further investigation of the system scaling challenge. It was found that in solving calcite scaling, other scale forms became dominant such as siderite and silica scales. Furthermore, it was found that one of the root causes of scale build-up was the presence of EOR polymer in the produced water.
Laboratory work evaluated the incumbent program for efficacy against siderite scale precipitation using an anoxic test method. Work focusing on the glue-like EOR polymer build-up has also been described, including chemical mitigation and remediation methods. Results showed that the incumbent treatment, whilst optimal for calcite scale, was not optimized for the overall multiple scaling scenario. Furthermore, the EOR polymer fouling mitigation required a totally new and unique treatment approach.
A summary of the field application and results of the new chemical strategy has been given illustrating a clear step change in the frequency of fouling in the production system. The paper concludes with a critique of how the laboratory data was representative of the field application. A final hypothesis is discussed, suggesting that EOR polymer breakthrough was a significant root cause of scale deposition due to the ease of deposition in the process system. Subsequently, this proved influential on the deposition of mineral scale and other solid deposits.
