Practice and understanding about water injection enhancement of ultra-low permeability oil reservoir in Yaoyingtai

The ultra-low permeability fractured reservoir in Yaoyingtai has a serious anisotropy and the water injection development has the characteristics of low degree of waterflooding reserves,high water injection pressure,small swept volume,obviously marching forward along high permeability zone,high waterflooding degree and abundant remaining oil in low permeability zone.Through different manners such as repeated perforation in water well,converted oil wells,staged fracturing of horizontal well,profile modification of water well and cyclic water injection,the water injection development effect has been greatly improved.