Residual Scale Inhibitor analysis in produced waters is recognised as an ongoing challenge for many offshore production environments. Scaled Solutions Ltd have made further developments to enable rapid, accurate, reliable and robust analysis for sulphonated & non-sulphonated polymers in oilfield brines.
The most critical factor to ensure quality analysis lies in the separation of the scale inhibitor species from the interfering oil/particulate/brine matrix commonly obtained in coreflood & real field samples.
We have developed and improved upon current standard industry practices to provide practical working solutions for high throughput laboratories , focussing on the following techniques:
High Pressure Liquid Chromatography (HPLC) is employed to provide a fully automated analysis profile for routine Performance & Core Flood analysis. This technique requires the test sample to be eluted through a chromatographic column at high pressure. The Scale Inhibitor is separated from the sample matrix through differences in their relative solubility to the HPLC mobile phase and stationary phase, or by differences in the hydrodynamic volume of the analytes. The chemistry of the column (and other instrumental conditions) can be altered to provide different degrees of separation. The Scale Inhibitor can then be directly quantified using one of several detection systems including UV, Charged Aerosol Detector (CAD) & Evaporative Light Scattering Detector (ELSD).
Solid Phase Extraction (SPE) allows Scaled Solutions Ltd to separate polymer/brine mixtures by the sample is loaded onto a cartridge with the polymer being retained and the interfering brine salts flushed out with a suitable solvent. Depending on the polymer chemistry we utilise various SPE stationary phases including Strong Anion Exchange (SAX), Weak Anion Exchange (WAX) and Carbon Loaded C8/C18.
Dialysis provides a means to separate the brine from the analyte by diffusion of the salts through a semi-permeable membrane from a region of high salt concentration to low concentration.