抄録
The occurrences of natural gas are considered to be very similar to those of oil. Herein the writer discusses them from the viewpoint of geology, geochemistry and geophysics.
1) The distribution of the oil and gas fields can be illustrated closely related to the isopach, lithofacies and restored section maps.
2) The chemical analysis of the organic matters in the source rocks are introduced. They can be the valuable indices to the origin of the natural gas.
3) The chemical properties of the natural gas in the various fields are considerably different and the mature evolution of the natural gas is the very interesting problem.
4) The geothermal distribution in the geologic structures are investigated.
5) The reservoir pressure distribution or the pressure gradient are examined. The causes of the abnormal reservoir pressure are considered.
