CSIA ON CO_2 AND ALKANES IN THE GAS PHASE OF LOW PERMEABILITY SEDIMENTARY ROCKS

摘要

Since the 1970ies, isotope fingerprinting on CO_2 and gaseous alkanes proved to be a powerful tool in hydrocarbon exploitation [1]. In particular, isotope fingerprinting allows distinguishing between methane of biogenic or thermogenic qrigin [2]. Recently, alkanes confined in low permeability rocks (shales) have drawn economical attention as non-conventional energy resource. The same rocks are equally of interest as targets for CO_2 sequestration (as caprocks), and for solid waste disposal (as host rocks), since they form natural barriers for fluid and gas migration. Characterisation of carbon, oxygen and hydrogen isotopes on CO_2 and alkanes can reveal information on the origin and mobility of gases in the pore space of argillaceous sedimentary rock series thus providing additional constraints on their aptitude to act as barriers for the confinement of fluids and gases.