Development Mechanism Research Of Advanced Water-injection Of Jurassic Xishanyao Reservoir In Niujuanhu Oil Field

Niujuan Jurassic Xishanyao reservoir is ultra-low permeability, low pressure, low mobility of the typical "three lows" sandstone reservoir. Its property is poor, heterogeneity serious and natural energy short. Its natural production capacity is low. It is difficult to develop it. Based on the successful experiences of other same kind reservoirs to develop, advanced water-injection development method is determined. By the means, the reservoir is developed economicly and effectivly. But several years later, some problems appears. The proportion of low production wells is high. The difference between blocks is large. The direction of water stream is apparent. Crude oil emulsification phenomenon is serious. Part of oil wells are critically water flooded at first. The conventional waterflood adjustment isn't ideal.This paper researches and analyzes the principle, adaptability, percolation mechanism, the mechanism of improving yield and recovery of the advanced water-injection in low permeability reservoirs. The paper researches reservoir features, reservoir heterogeneity and rock wettability in Jurassic Xishanyao reservoir. The reservoir heterogeneity of porosity, permeability and oil saturation is serious within layers and planes. The reservoir rock surface exists inhomogeneous features of close water, weak hydrophilic and weak oil wettability. The feature of close oil enhances while permeability increases.Then the paper completes the research of the movement disciplinarian of oil and water in Niujuanhu oil field. The waterline propulsion direction is more onefold in Niujuanhu oilfield. The response and water breakthrough of oil wells in oil-water-well rows are quick. Waterline propulsion speed in oil-water-well rows is fast. Injected water dashes along the oil dry layer vertically. The paper explains the phenomenons and puts forward five reasons why the implementation effect of advanced waterflooding isn't ideal. Low porosity, ultra-low permeability, low pressure and natural unsaturated are objective reasons. The excessive fracturing of oil Wells caused the connectivity between oil wells and water wells. Oversized row spacing can't establish effective pressure field. Water injection pressure over the fracturepressure causes serious water channeling. The pressure increased rate is too quick to cause the crude oil to hide.Mild water-injected technology policy is adopted in Niujuanhu oil field. The paper demonstrates the reasonable well row space, and puts forward reasonable well pattern adjustment scheme of Niujuanhu oil field to guide oilfield development.