Marine drilling riser is subject to complicated environmental loads which include top motions due to Mobile Offshore Drilling Unit (MODU), wave loads and current loads. Cyclic dynamic loads will cause severe fatigue accumulation along the drilling riser system, especially at the subsea well head (WH).
Statoil and BP have carried out a comprehensive model test program on drilling riser in MARINTEK’s Towing Tank in February 2015. The objective is to validate and verify software predictions of drilling riser behaviour under various environmental conditions by use of model test data.
Six drilling riser configurations were tested, including different components such as Upper Flex Joint (UFJ), tensioner, marine riser, Lower Marine Riser Package (LMRP), Blow-Out Preventer (BOP), Lower Flex Joint (LFJ), buoyancy elements and seabed boundary model.
The drilling riser models were tested in different load conditions:
1. Forced top motion tests
2. Regular wave test
3. Combined regular wave and towing test
4. Irregular wave test
5. Combined irregular wave and towing test
6. Towing test (VIV)
Measurements were made of micro bending strains and accelerations along the riser in both In-Line (IL) and Cross-Flow (CF) directions. Video recordings were made both above and under water.
In this paper, the test set-up and test program are presented. Comparisons of results between model test and RIFLEX simulation are presented on selected cases. Preliminary results show that the drilling riser model tests are able to capture the typical dynamic responses observed from field measurement, and the comparison between model test and RIFLEX simulation is promising.