| 摘要 |
In one aspect of the invention, tools are actuated or operated within a well by selectively expanding the tool wall. To actuate the tool, the tool wall (225) is urged outward past its elastic limits. The expanding wall physicall y unlocks a locking ring (280) which then ulocks a piston (260). Thereafter, hydraulic pressure difference are employed to move the piston to operate the downhole tool. In another aspect of the invention, a first piece of casing i s joined to a second, larger diameter casing. By expanding the diameter of the first piece of casing into contact with the second piece of casing, the two are joined together. The joint is formed with helical formations in a manner that provides flow paths around the intersection of the two members for the passage of cement or other fluid.
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