BMT Scientific Marine Services Inc., a subsidiary of BMT Group Ltd, has developed a sensor assembly and installation tool that permits strain sensors to be installed on an underwater pipeline using a Remotely Operated Vehicle (ROV).
Known as a Subsea Strain Sensor Assembly (SSSA), it is attached to a pipeline or riser in depths of up to 10,000 ft below sea level. Once secured onto the pipe, the sensor assembly measures static and dynamic tensile and bending strain and alerts offshore operators if the pipe is likely to be strained excessively or to suffer fatigue damage in future.
Pre-installed SSSAs designed by BMT are already being used around the world, including off the coast of Angola on BP's Greater Plutonio Block 18 Hybrid Riser Tower, Petrobras's P-52 Free Standing Riser Tower off the coast of Brazil and Chevron Tahiti Spar's Pull Tubes and SCR in the Gulf of Mexico. BMT SSSAs are also about to be used on steel catenary risers and oil offloading lines in TOTAL's AKPO Field offshore Nigeria and on Petrobras America's Cascade-Chinook Free Standing Risers, in the Gulf of Mexico.
A key feature of the ROV Deployable package is the stable support frame for the sensor package. Before installation starts, a support frame is clamped to the riser by the ROV to provide an anchor for the ROV, and to ensure that the sensors can be fitted or adjusted without causing any damage to them.