Revised parameter to measure and compile the degree of organic metamorphism of the Tertiary and the upper Cretaceous systems based on vitrinite reflectance value (R0) are introduced; i. e. V-value, decupled R0, ν-value along iso-rank direction in the traditional proximate rank classification diagram (Fig. 4). Numerous data of proximate analysis of the Tertiary and the Cretaceous coalfields and coal-bealing strata are classified by ν-value to expose regional and stratigraphic variation of organic metamorphism (Figs. 5, 6). Depth-vitrinite reflectance gradient in oil exploring deep drill holes in the western flank of the Hidaka orogenic belt is confirmed to correspond the smaller value to lower terrestrial heat flow region. Since the pattern of organic metamorphism and the regional variation of terrestrial heat flow is satisfactorily correlated, the depth of petroleum generation zone is able to be predicted based on surface organic metamorphism degree and geothermal structure in connection with subsurface vitrinite reflectance gradient, and finally regional restriction for f abourable petroleum exploration is suggested from the view point of organic metamorphism.
Low concentration surfactant flooding has been used as one of enhanced oil recovery methods. Recently high concentration process known as microemulsion flood has been developed in place of low concentration one. Nevertheless, it was considered to be essencial to develop effective chemicals for low concentration surfactant flooding, because of poor permeability and dirty sand of reservoir in Japan. For this reason, in this paper, the experimental results were discussed to select effective surfactants and other additives by following methods. The three screening procedures were adopted for selecting the effective one. The first method was shaking test, in which oil saturated specimens were sunk in aqueous solution of surfactants and shaked for two days during experiment in constant temperature bath. As the results, residual oils were washed away from cores. These oils were separated from waters and then measured the volumes. The second and third tests were oil displacement procedures through column of sand and core. At first, effective surfactants had been selected from many kinds of chemicals by above mentioned procedure. Their each one or its combinations were provided for second and third processes. As the results, it was confirmed that the effective surfactants were two composited chemicals of polyoxiethylen-nonylphenol-ether, dodecylbenzenulfonicacid-calcium and polyethylenglycol-polypropylenglycolethers.