Coiled Oilfield Tubing (CT) continually finds new markets, and has experienced continued growth in extended reach wells and high-pressure service. One major improvement is in the quality possible at skelp end welds, when continuously tapered strip1  is employed to join strip of the same thickness. In this paper, the following are discussed:

  1. Tapered strip and tubing dimensional specifications at all points along the tubing.

  2. Design of CT employing continuously tapered strips.

  3. Effect of tapered wall thickness on theoretical fatigue life.

  4. Effect of skelp-end welds of the same thickness, as compared with those of conventional tapering, on overall string life.

  5. Suggested amount of tubing to be removed if needed during servicing operations.

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