The petrological and sedimentalogical studies of the Neogene rocks developed in and around the basins in Akita, Yamagata and Niigata Prefectures have been carried out. As for the Shionegawa and the Harukigawa routes in the Shinjo Basin in Yamagata Prefecture, as mentioned previously, there were observed some differences in the distribution of the non-hydrocarbon constituents both in the case of the pyroclastic rocks and in the fine clastic sediments. Some physical and chemical studies concerning the Miocene deposits, so-called black shale and hard shale, have been also undertaken for the purpose of investigation the sedimentary petrology of those resource-rocks of petroleum and the discussions are dealt with in this present paper. Further, it is suggested that their occurence affords important criteria for the interpretation of the complex pheomena related with the sedimentation and volcanisms during deposition of the Neogene sediments developed in the oil fields of Japan.
The stratigraphy and the structure of the formations of middle Miocene to Pliocene in age in the Ota-Omama district, are described. In connection with the paleogeography of the northwestern Kantõ region, the writers stress that the upper Miocene marine sediments influenced strongly by the oceanic waters at the time of their deposition are distributed in the district.
The Chinshui oil field succeeded in the well No. 5 for the first time. This is the second oil field in Taiwan which produces gas in great quantities with oil. Petroleum is producing from the lowest Shukkoko sandstone shale formation while gas is flowing from the upper sandstone shale formation and the white sandstone formation. The structure of this oil field is 5 km in length and is of anticlinal structure with somewhat steeperwest wing. Forty-seven wells were drilled up to the present and produced about 9, 200 kl petroleum and approximately 1, 870, 000, 000 m3 gas as of the end of April, 1956. This paper contains the result of the studies on the shallow zone Keichikurin formation in collaboration with the Chuton gas field, the conclusion of which is as follows: 1. In the sandstone zone at the top of Keichikurin formation rejuvenation of 1-2 wells of Chihchitze area by the gunperforation is possible, but in the Ia layer rejuvenation can not be expected. Both the underground structures of the sandstone zone at the top of Keichikurin and the Ia layer of Laotien Liao area located further below Chihchize, and there is a little hope of success there. 2. Judging from the change in the thickness of the each formation and etc, it is advisable to advance an examination into further lower formation by carrying out exploration in the depth.
The writers undertook laboratory study for the purpose of examining relation between factors affecting f factor in gas lift well. By the results of the experiment, writers obtained the equation, f=aρb where f is f faxtor; ρ is fluid density; a and b are the function of the flow rate of liquid and the inside diameter of lift pipe, respectively. By application of the equation, writers are able to calculate f factor for a much wider range of gas-oil-ratio.