Abstract
A CO2 tertiary flood is being studied in Kubiki field, which located in Niigata prefecture facing the Japan sea, since 1988 with an inverted four-spot pattern.
First 3 year of the project was spent for pre-injection study. Well logs and core analyses were used to predict the residual oil saturation. Bottom-hole fluid sample was taken to measure PVT properties including MMP and to perform core-flooding under reservoir condition. Using these results, numerical simulation both for water-flooding stage since 1977 amd CO2 injection stage is now being preformed. The present paper summarizes the result of these pre-injection study.
CO2 injection was commenced on February, 1991. The design rate of the injection plant is 15 tons of CO2 a day. During injection, well logs and fluid samples are taken periodically and bottom-hole pressures are automatically recorded to a personal computer by the surface readout bottom-hole pressure monitoring system.
