Comparison of the gas hydrate plugging potentials of a set of crude oils from the Norwegian continental shelf using chemometric decomposition of GC–FID data

Potential complications in the exploitation of subsea oil-fields due to gas hydrate plugs in the transportation lines lead us to explore the suitability of two routinely performed and thus easily available chemical analysis methods coupled with chemometric analysis to separate oils with high plugging potential from dispersion oils. Genov et al. (Organic Geochemistry 39 (2008) 1229–1234) successfully developed a method to separate these based on FT-IR spectroscopy coupled with chemometric analysis. Using whole-oil GC–FID data, we are able to present successful separation of these same oils in this paper and to deliver estimated molecular weight ranges showing significant impact on the plugging potential of different crudes analysed. We have localised retention time areas both in the chromatographic peak and the UCM data that strongly influence hydrate plug inhibition in some of the oils from the sample set. The results point to naturally occurring branched molecules in the nC9–nC13 range which, coupled with our prior results based on functional group allocation, suggest that ester or other carbonyl moieties in these components inhibit clathrate hydrate plug build-up.

► PCA of GC–FID data helps differentiate crude oils with high and low plugging potential.
► Plugging inhibitors can be pinpointed to non-straight chained components in the nC9–nC13 range.
► Plugging promoters are suggested to be situated between nC14 and nC20.
► Standard analytical techniques and PCA can be used as a screening for hydrate plugging potential.