Hydrogen influence on transformation of terrigenous reservoir physical and mechanical properties

The article aims to describe a methodology for studying the dynamic, stress-strain properties and density of core samples before and after exposure to hydrogen. The Stages of sample studies and the instruments used in laboratory experiments are examined on the example of core samples taken from the Bobrikov formations in the Volga-Ural oil-and-gas bearing region. A comparative analysis of dynamic properties, density, Young’s modulus and Poisson’s ratio was carried out before and after ex-posure to hydrogen. It was discovered that after exposure to this gas, interval transit time of acoustic P-wave and S-wave through the samples decreased by an average of 2.4%; Young’s modulus increased by 6.5%, while Poisson’s ratio remained virtually unchanged. Besides, the research results demonstrat-ed an increase in sample density by 1.1%. The analysis of correlation dependencies revealed a typical change in interrelation of the parameters of P-wave interval transit time with Young’s modulus and S-wave interval transit time after samples exposure to hydrogen. Overall, based upon the results of the studies of density, dynamic properties, and Young’s modulus, there is evidence of weakening of the stress-strain properties in the core samples. However, such change does not have a major effect on their absolute values. Analysis of the results collected during laboratory experiments shows that the consid-ered horizon could potentially be the formation for the storage of a methane-hydrogen mixture.