Half-cementing well completion pipe string

The utility model relates to the technologies of well-drilling, well completion and cementation in petroleum industry, and particularly provides a half-cementing well completion pipe string, so as to overcome the diameter reducing problem of the plug-drilling-free half-cementing technology employing no inner pipe. The well completion pipe string comprises an external casing packer, a sizing collar and a casing pipe, which are sequentially connected, wherein a blanking plug and a rubber plug are positioned in the external casing packer and the sizing collar; a positioning groove is arranged on the inner wall of the external casing packer, and the positioning block of the blanking rubber is embedded in the positioning groove; and a closing groove is arranged on the inner wall of the sizing collar, and the closing block on the blanking rubber is embedded in the closing groove. The half-cementing well completion pipe string is applicable to the non-inner pipe half-cementing operation, and the drift diameter of the well completion tool of the pipe string is equal to the internal diameter of the casing pipe.