Analysis of the Bazhenov Formation Oils Using Gc×Gc-Ms and Isotope Ratio Mass Spectrometry (for Oilfields in Shirotnoe Priobje Area)

Oil identification is required on each stage of field development: from exploration to production. In case of enhanced oil recovery (EOR) implementation oil analysis is needed for assessment to efficiency of the process. The current research is devoted to analysis of oils from the oilfield in central part of West Siberia petroleum bazin (the Bazhenov Formation). The objectives were to detect changes in oil molecular and isotope composition caused by catagenesis or additional thermal treatment of the Bazhenov formation kerogen rich core; to study natural variations of oil composition and to estimate layer which is source for oil components. We conducted GC×GCMS analyses, isotope ratio studies of oil and core extracts. We demonstrated, that molecular parameters allow to distinguish between natural oils and oils after thermal treatment of the Bazhenov sequence core. Carbon isotope composition (δ13C, ‰) of the samples represents variations in catagenesis, whereas hydrogen isotope composition differs dramatically for natural fluids and for oils obtained from core after thermal impact. Obtained trends are applicable for evaluation of organic matter catagenesis within the Bazhenov Formation; assessment to transformation resulted from EOR on the specified object requires additional measurements on core samples from the object (well, oilfield, etc.)