Next Generation Oilfield on-Site Trace Chemicals Analysis by SERS

Accurate and precise monitoring of chemical additives in oilfield brine is an important aspect of oil and gas operations towards corrosion control and flow assurance. Many operators are required to monitor the residual concentrations of chemical additives in production systems at specific locations to monitor and troubleshoot factors affecting chemical deliverability and performance. However, residual measurements are extremely problematic due to many factors, including the surface active nature of the chemicals and high ionic strength of the brine. The error on residual measurements can often be over 100%. Residual measurement typically requires the collection of a water sample, which often needs to be transported to a centralized analytical laboratory. Analytical techniques used to measure residuals are based on several combinations of separation (e.g. chromatography, liquid-liquid extraction, etc.) and detection (e.g. various forms of spectroscopy). However, most of these methods lack portability and require tedious laboratory procedures located off-site. The current paper describes a nanotechnology-enabled Raman spectroscopy method developed and tested for monitoring chemical inhibitor residuals. Development of this technology with handheld instrumentation provides better detection and quantification of chemical additives in the field and reduces time and cost compared to sending samples to off-site laboratories for data collection.