A modified method to calculate rational well spacing density in late high water cut stage(development stage)

Most oilfields in East China have been in late high water cut stage or extra high water cut stage.Present well patterns need to be infilled to improve development efficiency,reduce composite water cut and slow down production decline.Previous well spacing density was based on V.N.Shelkachev formula,which didn't consider the development characteristics of high water cut.This paper uses net present value principle to establish a new and comprehensive model for calculating well spacing density in late high water cut stage with consideration of waterflood sweep efficiency,injection-to-producing-well ratio as well as some development characteristics.Compared with the former method,this method is more comprehensive and more suitable to calculate well spacing density in the late development life of an oilfield.Practical analysis and calculation indicate that this modified method is feasible and practical for making investment decisions in the late life of oilfield development.