The Study On Waterflooding Exploitation Feature And Adjustment Technology In Extra High Water-cut Stage

At present most oilfields in the world have been developed by water flooding, because water flooding can make the oilfield maintain high-volume withdrawal for a long time and it can also improve the final recovery efficiency greatly. In our country, some oilfields have been in the later stage of water flooding development, and many oil wells have been with high water cut or super high water cut. Oil fields are confronted with a lot of difficulty after they entered into the extra high water-cut stage, such as the sharp aggrandizement of liquid-oil ratio, the obviously augmentation of treatment workload and cost that in order to maintain the steady production of oil field and so on. For controlling water-cut rise and production decline and enhancing oilfields recovery, the key is to recognize the characteristic of exploitation and production technological strategy limits.This dissertation has made full analyse to all the development phase and each production characteristic of Xingbei region in Daqing Oilfield. And on the base of which, according to the statistic of sealed core drill data of Daqing Oilfield, reservoir parameters of Xingbei development zone and dynamic production data, mining characteristics with ultra-high water cut is studied. Oil-water relative permeability curve shape of the area is classified and different types of oil-water relative permeability curves and the characteristics of seepage is contrasted, using three sealed core drill and sixty-seven relative permeability curve and dynamic production data. These establish the foundation for the mining characteristics with ultra-high water-cut in Xingbei development zone. And it launches the study on water displacement feature and proposes a reasonable measure of water displacement theory in extra high water-cut stage-- the method of two straight lines. The new method better reflected characteristics of the development in extra high water-cut stage. The fluid productivity index, injectivity index, changes of rising water of Xingbei development zone were analyze. Liquid index and absorbent index have different changes because different adjustment policies in extra high water-cut stage. By studying the changes of relationship formation pressure, oil recovery and the liquid indexe, limit of flow pressure and the ratio of oil and water in Xingbei development zone in extra high water-cut stage were determined. Reasonable formation pressure of Xingbei development zone with ultra-high water cut should be near the original formation pressure. The distribution remaining oil is given, the cause is analyzed and the next adjustment policy is determined, through the primary means of reservoir engineering and reservoir simulation. Chemical flooding on the main layer and strengthen relations of injection and production on the non-essential layer were suggested. It not only has a certain academic value, but also can provide more precious experiments and technical support for the development of other oil fields in extra high water-cut stage.