Research on effect of water injection pressure on casing damage in Pu-Bei oil field

Based on statistical analysis on the distribution of casing damage in Pu-Bei oilfield, laboratory simulating experiment was done to establish Instability Model of rock body and water injection pressure that can prevent casing damaging was obtained. Analysis results show that the main reason of casing damage in Pu-Bei oilfield is the interlayer slipping between lays with different lithologic characters. Water injection pressure is the driving force that leads to interlayer slipping. The hydration of mudstone layer above water injection formation is the significant reason that induces interlayer slipping. It is suggested that Control the retting and hydration of mudstone layer to prevent casing damage and decrease water injection nearby fault as far as possible to prevent retting and slipping of fault.