Seal bores have been in use to allow a string to be lowered downhole and secured and sealed. Typically, a packer or plug has a polished bore in it to act as the receptacle for the lower end of a string run into the well from the surface after the packer or plug is set. At the lower end of the string is what is known as a tieback seal assembly. This assembly comprised a male component to go into the female seal bore. There is a single or multiple grooves on the male component to hold a seal. The seal can be an o-ring or a stack of chevron shaped rings. Regardless of the nature of the seal material used, there is an interference fit between the seal material and the surrounding bore to energize the seal material in the seal bore. Frequently, the seal bore is polished to minimize damage to the seal assembly during the insertion process. At times, guides or centralizers are used to assist in the alignment of the male component with the seal into the seal bore. One such device is illustrated in U.S. Pat. No. 5,330,001. Other art, such as U.S. Pat. Nos. 6,098,717 and 6,446,724 illustrate expanding one tubular into another.
Typically, the seal or seals are placed in a groove in the tieback assembly male component. The removal of metal that is necessary to form the groove or grooves for holding the seal or seals takes away a portion of the wall and reduces the pressure rating of the connection. What is needed and has not previously been provided is a connection that removes this pressure rating reduction due to the presence of the groove or grooves to hold a seal or seals. The present invention addresses this need by providing a tieback assembly where wall portions are not removed to provide a mounting location for a seal or seals. Instead, the concept of expansion in place is used. Where a seal is actually used, it can be in the form of an exterior coating that gets forced into contact with the seal bore receptacle as a result of expansion. Sealing or anchoring with metal-to-metal contact without the use of resilient seals is contemplated using the expansion technique. These and other advantages of the present invention will become more apparent to those skilled in the art from a review of the description of the preferred embodiment and the claims, which appear below.
USPTO Backgrounds
USPTO Backgrounds