| 摘要 |
An apparatus and method for expanding a lower string of casing into friction al contact with an upper string of casing, and thereby hanging the lower string of casing onto the upper string of casing is provided. The apparatus essentially defines a lower string of casing having a separation region form ed in the top end thereof. The lower string of casing is run into the wellbore, and positioned so that the top end overlaps with the bottom end of an upper string of casing already cemented into the wellbore. The top end of the lowe r casing string is expanded below the depth of the separation region into frictional contact with the upper string of casing. At the same time, or shortly thereafter, the top end of the upper string of casing is expanded. A s the portion of the lower casing string having the separation region is expanded, the casing severs into upper and lower portions. The upper portion can then be removed from the wellbore, leaving a lower string of casing expanded into physical contact with an upper string of casing. The separatio n region may be formed by heat treating the tubular at the point of desired severance. In another aspect, the separation region may comprise the connection between two tubulars. This involves connecting two tubulars to fo rm the tubular to be expanded downhole. The tubular formed is then lowered into the wellbore and expanded at the connection to separate the tubular.
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