| 摘要 |
A casing patch is disclosed which uses one or more fins which elastically flex to accept a casing stub. The casing stub is prepared with a dressing tool containing a special mill to obtain the requisite finish on its outer surface prior to insertion of the casing patch. The flexible fin or fins provide a metal-to-metal seal to the outer surface of the casing patch and a grip assembly holds the joint together. In certain applications, the fins can be combined with a resilient seal where the fins preferably provide a complete extrusion barrier to the resilient seals. Using the fins which preferably are integral to the body, alone or in combination with a resilient seal or seals, the wall thickness of the joint can be maintained at thicker values for a given size as compared to prior designs, thus, ensuring a sufficient pressure rating for the joint which is at least equal to the rating of the casing stub. |
