For the secondary recovery of oil field, the history of production and its relation to the physical condition of the reservoir should be fully studied at first. In this paper the fundamental problems about the reservoir conditions of the first zone of Innai oil field are discussed upon the latest data, namely, the structure of the reservoir, the characteristics of crude and connate water, the production history regarding to the individual well as well as to the reservoir as a whole, the relation between the production potential and daily well production the oil reserves, the relation between oil and water production, and finally gas production.
Tokyo Natural gas field discovered recently is one of the important hydrocarbon resources in Japan. This field is situated along the seashore of the Tokyo Bay, and the geological formations consist mainly of Neogene Tertiary and Quaternary deposits. These formations belong to the marine sediments. The high chlorinity and reducing condition of this gas-bearing underground water are easily understood from the origin and present high gas pontentiality of the field. We surveyed this field mainly on the underground water by geochemical method. In this paper, at the beginning, we show the locations of surveyed wells and oabserved data of them on a map and a table. Next, we discuss the vertical distribution of chemical elements and their geochemical correlations in order to make clear the gas potentiality and productivity of the deeper horizons. Then, we studied the regional distribution of chemical element. Thus we discussed the mutual relation of the distribution of chemical elements and geology, and obtained the regional geochemical correlation. Finally we conclude that the noticeable area in gas prospecting consists from the, following scquence. Southern half of Edogawa-ku, Southern part of Chuo-ku, Koto-ku, Eastern part of Minato-ku.
The natural Gas of the Oshamanbe Area seems to be derived from the Setana formation (uper most Pliocene), which was overlain by Alluvial or Diluvial sediments. Judging from the chemical nature of this gas it is Tertiary gas of CH4-N2 system, and gas-water ratio seems to increase according to its depth. Two gas-bearing horizons are recognised in 40-60m and 140m in depth.