Technology from Europe:
Norway/Finland

Connector for risers proves itself in field tests

Norwegian firm Gram has been developing a 7-1/16 -in. connector for use in offshore risers, touting such improvements as reduced rig-up times and greater safety (no falling objects). Until recently, however, the company did not know for certain whether the new connector could function sufficiently in its intended role. A field test was still needed. Gram will also perform a full-scale test to qualify the connector for subsea use in accordance to ISO 13628-7. The physical test will be performed at EWI in Ohio by the end of this summer.

Fig. 1. Field trials were successfully conducted with ConocoPhillips and BJ Services at Ekofisk field in the North Sea.

The Gram connector was first introduced to BJ Services and ConocoPhillips about one year ago. After some technical discussions between Gram, BJ Services and ConocoPhillips, a decision was made to manufacture a full-bore, 7-1/16 -in. connector for use in a coiled tubing operation at Ekofisk 2/4-X in the North Sea. The connector was to be installed above a coiled tubing BOP to ensure full, well-kill capability, should the connector leak at any stage during the test.

To the firms' satisfaction, the connector performed very well during field trials, Fig. 1. It was placed where the bottomhole assemblies are installed into the riser, allowing for multiple, open-and-close functions on the same well (X – 34=10). This would not ordinarily occur, if the connector were part of the riser stack.

The operation proved that even with multiple open-and-close functioning, the connector was still able to perform to the high standards required, as per coiled tubing regulations, Fig. 2. When the connector was exposed to tension and compression loading from the well's cool-down and warm-up effects, no leaks were observed. Upon inspection, the sealing ring did not show any signs of mechanical loading or damage, due to exposure to well fluids and temperature.

Fig. 2. This 7-1/16 -in. connector has proven to offer much faster rig-up times and improved safety during operation.

The field trial provided the firms a great deal of confidence in the connector's abilities. ConocoPhillips and BJ Services subsequently prepared a design specification for a complete riser package (from shear to BOP) using the new connector for the Ekofisk X platform.