In this paper, the effects of carboxyl content, compositions of polymer and brine, and temperature on the flow properties of polymer solutions are discussed. Twenty kinds of partially hydrolyzed polyacrylamides were used as polymer samples. Brine which contained mono-valent (Na+) or divalent (Ca2+) were used. The flow properties of polymer solutions such as apparent viscosity, screen factor, resistance factor and residual resistance factor were measured. The results are summarized as follows: (1) Resistance factor, residual resistance factor, viscosity, and screen factor all increased with carboxyl content. This increase was much higher for solutions of low brine concentration than those of high brine concentration. (2) A grater decrease in resistance factor and viscosity due to cation was observed in the COO- polymer solutions compared to the COO- & SO3-. (3) Resistance factor, viscosity and screen factor at 50°C decreased to 40-80% of those at 25°C. (4) The addition of radical scavenger did to a limited extent, help control the heat deterioration of polymer.
On the basis of calcareous nannofossil assemblages in samples recovered at six sites in the North Atlantic Ocean during DSDP-IPOD Leg 94, eleven calcareous nannofossil biohorizons are recognized in the Quaternary sequences deposited at middle and high latitudes. Correlation of these biohorizons with the magnetostratigraphy is established, and ages of all datums are estimated by interpolations between magnetic reversals (CLEMENT and ROBINSON, 1987; TAKAYAMA and SATO, 1987). The calcareous nannofossil and the foraminiferal assemblages of the Yabuta and the Junicho formations in Toyama Prefecture and the Omma formation at its type locality in Kanazawa City are described in detail. Based on the above mentioned results of DSDP-IPOD Leg 94, the Yabuta, the Junicho and the Omma formations are late Pliocene, Plio-Pleistocene and Pleistocene in age, respectively. In 1984, small mammalian fossil bone of Stegodon aurorae (elephant) was found from the upper Omma formation. This level of S. aurorae is probably referred to the stratigraphic interval between the calcareous nannofossil biohorizon (5) (0.83Ma) and the Brunhes/Matuyama boundary of the magnetostratigraphy (0.73Ma). The Omma formation overlies unconformably the Saikawa formation. In contrast to the Omma formation, the Saikawa formation contains middle to lower Miocene calcareous nannofossils. The upper Miocene and the Pliocene sediments are, therefore, completely missing between these two formations.
Quantitative basin evaluation becomes a fundamental requirement of petroleum exploration, and it includes estimating the timing and amount of petroleum generation and migration. To understand a regional petroleum geology, all geological processes must be related one to another, and the information from each process must be integrated in a systematic manner. Simulation modeling is a very useful method to execute such process of thinking. A deductive forward model for this purpose was set up to simulate fluid flow compaction, heat transfer, maturation of organic matter, and hydrocarbon generation. This paper introduces basic theoretical aspects of the model. The model, then, was applied to one of the oil field in the Niigata basin where a downward migration has been implied from the Nanatani mudstone to the lowest member Green Tuff. Through an application, the model reveals that the downward migration has occurred through most of the geologic time mainly because of capillary effects rather than regional hydrodynanic pressure gradients. For the shallower turbidite reservoirs, the model experiments indicate that the sandstone geometry is very sensitive for the hydrocarbon migration path ways. This suggests that capillary effects again play a significant role for a local migration pattern. The geologic data should be re-examined for the above hypothetical capillary effects on hydrocarbon migration.