Research and Application of the Properties Variation Regularity of Water Injection Reservoirs in S Offshore Oilfield

Water-injection is a main measure to improve the efficiency of oilfield development,long-term waterinjection has a great influence on the properties of reservoir. Through the analysis of the porosity,permeability, crude oil viscosity of S oilfield,the changes of water flooding and influence between them are compared,on the basis,the rule of the variation of reservoir properties are summarized before and after water injection development,the relationship between dynamic changes of reservoir properties and reservoir production are analyzed. Studies suggest that: after a long period of water flooding,the average pore radius,average porosity and permeability of S oil field have increased,but exhibit two opposite trends: increasing the high permeability reservoir permeability,large pore number increased gradually; reservoir porosity,permeability of low permeability less. The reservoirs of these two opposing trends lead to more serious reservoir heterogeneity,reservoir interlayer contradiction. Crude oil properties showed increased viscosity,resin and asphaltene content increased,the trend of deterioration. By taking layering acidification,stratified injection profile control and optimization measures,S offshore oilfield achieved good effect of increasing oil.