Real Time Operating Limits
Real Time Operating Limits (RTOL) is used to select the operating limits for running the Ormen Lange EDP and LRP from the West Navigator. The system reads actual measured current data from the Fugro ADCP (primary source) and the Wave Rider Buoy (secondary source). Based on the measured current RTOL selects the relevant operating envelope with respect to the actual depth of riser run. This enables the operating limits to be optimized with respect to actual current conditions rather than assuming the worst case conditions (i.e. 1 year return current).
Optimize operating limits, Multiple operation modes,Expand time window for operations
Weather and ocean current data from rig, Weather forecast from Storm / MI every 5-10 min.
Predict remaining fatigue life/time to next inspection, Fatigue tracking based on actual data
RTOL can then be used to assess the operability when running the riser by comparing the actual and forecast sea conditions (i.e. wave Hs , Tz) with the representative envelopes. The real time seastates are taken from the Wave Rider Buoy (primary source) and the rig (secondary source). Forecast seastate data is taken from the Orman Lange weather website.
The RTOL can be set to automatically update the current and seastate data every 2 hours and this is accomplished via an internet (web) based file transfer. In addition to this it is possible to enter a current profile manually. This facility has been included to enable the operating limits to be established in the event of network interruption. In the event of a network interruption a backup procedure is implemented to read current velocity directly from the Fugro ADCP (i.e. at 6 water depths). The current profile can then be entered manually in RTOL.