Analysis of chemical residuals is one of many components in the complex matrix that is the management of pipeline integrity in the worldwide Oil and Gas industry.
Chemical dosing and tracking
Production chemicals, such as corrosion inhibitors and biocides, are dosed into the pipelines in order to safeguard them from degradation (e.g. chemically and microbially induced corrosion). . However, for this to give effective protection throughout the system, these chemicals must reach all areas of the pipeline. To ensure this is happening, at the required dosage, requires timely and accurate testing of chemical residuals (i.e. how much of the dosed chemical is left at the other end of the length of pipeline of interest).
Traditional approaches to testing: lab vs portable
Traditionally, companies have relied on onshore, lab-based tests for residual analysis, prized for their accuracy but often accompanied by significant time delays. Waiting for lab results can impede decision-making and hinder proactive measures.
Recognising this bottleneck, the industry has embraced portable testing methods, providing results within an hour. This shift has transformed the monitoring process, enabling swift responses and enhancing operational efficiency.
Although a quick result may be gained, many of the available portable analyses are more qualitative (yes/no/maybe) than quantitative (how much). It may tell you there is some inhibitor at the required destination, but is it enough? (risking corrosion), or is it being overdosed? (with unnecessary additional costs).
Rapid qualitative methods used offshore include methyl orange titration, for corrosion inhibitor analysis, and iodometric titration, for THPS-based biocide analysis. Neither method gives accurate quantification, which can be a problem when companies need to understand whether an appropriate dose level of chemical has been applied.
New approaches
New technologies have been developed to overcome these challenges, allowing for rapid and quantitative analysis of chemical residuals at site (instead of sending them away to a distant laboratory and waiting). One example (the OMMICA THPS kit) uses colourimetry, combined with precision measurement techniques, to give accurate results.
Encouraging collaboration between industry stakeholders and research institutions can drive innovation in analysis methods, to improve pipeline protection strategies. For example, combining microbial ATP testing with residual colourimetry not only tells you if your chemical is reaching the desired location at the desired dosage, but will also give you a near real time level of microbiological organisms.
Conclusion
In conclusion, traditional residual analysis can lack accuracy. Designing holistic analysis approaches, combining cost effective quantitative portable testing methods with other innovative techniques, companies can gain much more meaningful residual analysis, which can assure pipeline integrity and potentially save chemical costs.
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