GC×GC Analysis of Novel 2α-Methyl Biomarker Compounds from a Large Middle East Oilfield

Comprehensive two-dimensional gas chromatography coupled with high resolution time-of-flight mass spectrometry (GCxGC-HRT) was used to explore and compare the chemical complexity of hopanoids and degradation products of hopanoid parent molecules in the heavy oil rim of a large Middle East oilfield. In particular, GCxGC-FID, GCxGC-ToF, and GCxGC-HRT enabled an in-depth characterization of the types and families of GC-amenable hopanoids and 2 alpha-methyl hopanoids along with degradation products derived from these compounds. Here we identify 2 alpha-methyl analogs of 8,14-secohopanoids, 2 alpha-methyl analogs of sesquiterpanoids, a 2 alpha-methyl tetracyclic terpanoid, as well as 2 alpha-methyl analogs of hopanoids and benzohopanoids. The compounds identified in this study are useful transformation products by various processes on the parent hopanoid compounds. This type of information provides valuable means to investigate reservoir complexities such as connectivity analysis.