EPR study of hydrocarbon generation potential of organic rich domanik rocks

Abstract

The objects of investigation were samples of domanik formation rocks of Berezovskaya area of Romashkinskoye oil field. Content of Mn2+, SO3−, SO2− ions, vanadyl-ions and free radicals has been estimated with the X-band (9.43 GHz) electron paramagnetic resonance (EPR) spectroscopy. Composition of rock and extracted from it bitumen has been studied with methods of thermal analysis, X-ray-structural analysis and gas chromatography. Significant differences in mineralogical composition and content of organic matter were revealed in samples taken from adjacent intervals. Pyrolytic experiments have been conducted to simulate kerogen maturation and petroleum generation. The increasing number of free radicals was registered in all samples after pyrolysis in a hydrogen atmosphere at 350°C. A new organic free radical C350 was registered after pyrolysis. It is suggested that domanik source rocks have not fully realized their hydrocarbon generation potential.

Keywords

• EPR spectroscopy
• generation potential
• kerogen
• pyrolysis
• domanik rocks