Abstract for Geological Survey Seminar, no.
Samples are octagonal prisms with long axes parallel to the vertical directions of the wells.
For investigating changes of microstructure in rock samples after measurements, blue dye epoxy-impregnated thin sections were prepared. The concentrations of methane to butane show similar range in both the VR and SR gases. VR gases are not necessarily enriched in carbon dioxide relative to the SR gases, which may be used to argue against an abiogenic hypothesis that methane in the VR gases was formed via the reduction of magmatic carbon dioxide. This can be explained again by assuming an addition of variable amounts of microbial methane to thermogenic hydrocarbons. The abiogenic methanes known so far are enriched in 13 C relative to regular thermogenic methanes, thus our data supports the argument against a significant contribution of such methane to the VR gases.