Casing damage mechanism and prevention-cure technique in high pressure injecting wells taking Shishen 100 oilfield as an example

The common problem existed in low permeability development is casing damage in high pressure injecting wells. Through on-site investigation and analysis in Shishen 100 oilfield, the basic rule of casing damage in high pressure injecting wells was discovered. The mainly factors are the influence of geology and well drilling, the casing damage mainly exists in clay rock interlayer nearby perforation and the perforation segment. The casing damage mechanism caused by these two above positions of high pressure injecting wells is studied emphatically and carry out in situ analysis. C-90 steel and casing pipe of 10.54mm were used when the high pressure injecting wells is finished and the high pressure was controlled by conversion, anti-boron pretreatment and acidification break-down technology. Field application has gotten better effect. Through the comprehensive prevention in recent years, the damage rate of high pressure injecting wells casing in Shishen 100 oilfield has decreased form 10.0% in 2000 to 3.3% in 2005.