The Japanese crude oil production has been steadily declining since 1937, the annual production of the fiscal year 1947 ending March 31, 1948 being 196, 000 kilolitres. It is also reported that about 88% of the total reserves of the proved oil fields owned by the Teikoku Oil Company, which is responsible for more than 90% of the domestic crude oil production, has been already depleted at that date. These circumstances are evidently due to the fact that no new oilpools of appreciable magnitude were discover ed in these years.
To establish a sound and comprehensive exploration program embracing oil producing and potential oil producing areas, the Petroleum Exploration Advancement Committee was established in the Mining Bureau of the Ministry of Commerce and Industry, at the instigation of the Natural Resources Section, G. H. Q., S. C. A. P. Under the planning of the Committee, extensive exploration works are now being carried on together with the compilation works to review the existing data.
Recent discovery of oil pools of fault trap type, such as at the Ishinazaka and Narahashi oil fields in Yamagata Prefecture, and those of stratigraphic trap type such as at the Shibata and Kaji oil fields in Niigata Prefecture, considerably enwidened the possible area of oil production. Also some structures underneath the alluvial plains in the petroliferous Tertiary basins were newly found by geophysical methods and wait further exploration.
In Hokkaido large structures of the Tertiary formation are now being explored, to test the oil possibility of the underlying Cretaceous, which abounds in oil seepages in certain areas of the district.
In short, the proved oil reserves of Japan is nearly exhausted, but the possibility of gaining new reserves is growing larger.
