Casing Repair Technique by Running 4 in Casing into 5(1/2) in Casing in Deep Wells

A study is carried out on deep well casing repair technique by running 4 in casing in 51/2 in casing in Huzhuangji Oilfield so as to improve waterflood well pattern, and handle interbed contradictions by stratification. Its main technical principle and technical indexes in operation are discussed. The result of application shows that well conditions are improved and its purposes of oil increment and stimulation improving are achieved.