| 摘要 |
A method for assembling two pipes into a single section of double-walled, radially-spaced, concentric pipe of sufficient strength for use in a wellbore in a permafrost zone in the earth is disclosed. Connectors having both left-hand and right-hand and internal and external threads connect corresponding internal and external threads on the pipe. Marks on the pipe ends indicate the various thread start points and, in combination with the left-hand and right-hand threads, permits proper alignment of the threads and facilitate threaded assembly of the two pipes into the double-walled section of pipe. Standard sizes of pipe may be used.
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