Abstract
Geochemical data from 13 wells in the Sea of Japan, Northern Honshu Area, were studied for their relationship to subsurface temperature. The basic geochemical data consisted of elemental analysis in kerogen, isotopic and organic analyses of mudstone, optial kerogen analysis and X-Ray mineral percentages of mudstone cuttings. These data were crossplotted against presumed present-day subsurface temperature.
A data analysis of the resulting crossplots implied that migration of oil occurs at a temperature range of 90°C to 105°C (Zone of flushing action) throughout the geologic section without respect to geologic age. The thermally matured zone (termed the zone of peak oil generation) probably corresponds to a temperature of 130°C.
