Offshore locations, which use large diameter coiled tubing for wellbore intervention, are currently limited by the lifting capacity of the cranes on the platforms. Often intervention projects require a longer length of coiled tubing on a spool than can be lifted onto the platform. Historically this problem has been resolved by connecting two or more spools of coiled tubing on the platform with a butt weld. Safety considerations, logistical issues and repeatable low-cycle fatigue performance have made this practice undesirable.
Spoolable connectors have addressed concerns associated with butt welds, however limitations on connector fatigue life, elastomer durability and post connection integrity verification exist.
A mechanical spoolable connector and an assembly skid have been introduced in the North Sea. An integrity test verifies the tensile strength of the newly made connection. Testing has shown that the connector does not affect ballooning of the coiled tubing due to bending under pressure.
The assembly skid provides improved safety and efficiency when handling, preparing and installing a spoolable connector. Remote operation of the pipe handing equipment has removed the operator from the work area when pipe is moving, which reduces the exposure to this hazardous task. This equipment provides a safe work environment for efficiently handling and preparing the coiled tubing during the assembly and disassembly process.
The connector together with the assembly skid was used successfully on the Gullfaks B platform in the Norwegian sector of the North Sea for sand cleanout, scale milling and plug setting operations.