The Theretical Research Of Water Driving In Sazhong Development Zone In The Period Of High Water Cut Stage

At present, the oil field development is faced with "three height" situation which are high water cut, high degree of recovery, high diminishing after 47 years'development in the Sazhong zone development. Currently, the comprehensive water cut of the oil field has achieved 91%. According to the conditions of water flooding exploitation, the effects of measures to increase oil have been deteriorated year by year. The water cut differences among the various layer systems have been only 3 ~ 4 percentage points. The room of structural adjustment has been very little. The difficulty for the comprehensive adjustment has obviously increased. Therefore, the theory of water driving oil in the Sazhong zone development at the period of high water cut should be deeply researched through the experiments of core driving indoor.In this paper, the changing laws of water driving laws in different zones at extra-high water cut stage are studied by analysis of the cores experimental data of the coring wells, statistical analysis of the field actual data, and reservoir engineering theories and methods. The effects of the geological factors make on the rate of water driving oil,the rising water cut rate curve and water driving decrease progressively curve are analyzed. The up-warping theoretical principle of water-drive laws curve at the extra-high water cut stage is derived by the oil-water relative permeability curves, and the up-warping range cause is analyzed. The reserves constant is calibrated and the chart of the water-drive curve applicable to high water cut stage is drawn. The relationship among differential pressure,water cut and injecting volume is analyzed through experiment, the factors that effect the rate of water driving oil are qualitative description. On the basis, the effect of long-time washing makes on the water flood recovery,relative permeability rate curve,water driving laws is researched. These achievements have important guiding meaning for production practice in Sazhong Zone development.