Apparatus and methodologies are provided for modifying the wellhead structure of a production well to seal the production well before subterranean fracturing operations. The apparatus includes an enclosure tubular and adapter 5 for sealingly engaging the polish rod extending from the wellhead structure, while maintaining the entire rod string in tension in a manner to ensure that the string and its connection with the downhole pump are not compromised. More specifically, the present preparations involve retaining the rod string in tension while removing at least the stuffing box from the wellhead structure, and 10 temporarily installing the enclosure tubular and adapter to seal the wellhead, preventing wellbore blowouts.