Wellhead blowout preventer for high-risk well replacement

The utility model discloses a high risk well change wellhead blowout preventer which comprises a first sleeve, a second sleeve and a third sleeve and further comprises a third barrier, a second barrier and a first barrier, the bottom end of the second sleeve is connected with the top end of the third sleeve, the first sleeve is fixedly sleeved on the outer side of the top end of the second sleeve, and the second sleeve is sleeved on the first barrier. A fastening sleeve is arranged between the first sleeve and the second sleeve, and the first sleeve, the second sleeve and the third sleeve are all located in soil; a first barrier and a second barrier are respectively arranged in the third casing pipe, a third barrier is arranged in the second casing pipe and the third casing pipe, the first barrier comprises a casing pipe suspension type packer, a sealing cover, a valve and an oil pipe screen pipe, and the second barrier comprises a removable blowout prevention packer. Three effective barriers are provided und