苏桥储气库群老井套管头选型与更换

Type selection and replacement of casing head for old wells in Suqiao Gas Storage Group

国内储气库主要以枯竭油气藏改建为主,由于储气库对井质量要求较高,因此储气库中原则上不再使用老井;即使利用老井也是在采取治理措施后,其密封性及安全性必须满足储气库完井要求的前提下做为采气井或观察井使用;更换套管头是老井利用中一项较为关键的措施,文中介绍了套管头结构、原理、选择及老井套管头更换、安装方法,现场应用2口井,经一个注采周期的运行,套管密封良好,没有出现泄漏现象,通过评估发生的相应费用,同比单井节约成本5 000万元左右,经济效益显著。

The domestic gas storages are mainly transformed from depleted oil/gas reservoirs. However, the gas storage usually has high demands for well quality, so in principle, the gas storage should not use old wells; even if old wells are used, they must be treated properly ifrst, and then used as gas producer or observation well on condition that their sealing performance and safety must meet the comple-tion requirment of gas storage. Replacing the casing head is a key measure in the utilization of old wells. This paper presents the casing head structure, principles, selection and the method for replacing and installing casing head for old wells. Casing head replacement was performed on two wells and after one injection-production period, the casing was well sealed with no leaking. Through evaluating the expenses occurred, this measure saves about 50 million Yuan compared to single well year-on-year, producing remarkable economic beneifts.