Dropped Object Protection Modelling for Subsea Equipment

Subsea x-tree is located at the seabed and contain hydrocarbon. The water depth for subsea operation exceed 1000 m which make it impossible for mankind to do the maintenance tasks at the seabed. Usually, the maintenance operation is done by using Remotely-Operated-Vehicle (ROV) and the cost to operate using ROV is high. Thus, subsea x-tree need to be free from any malfunction or damage. Dropped object or trawling gear from fishing activities are the objects that can collide with the subsea x-tree. This type of collision can cause significant damage and may result in hydrocarbon release. Subsea x-tree need to be equipment with a protective structure so that it can withstand the impact of collision from the dropped object or trawling gear. In this project, a protective structure was design by following NORSORK U-001 and U-002 standards together with the improvement design from Glass Reinforced Plastic (GRP) protective cover from HighComp. The speed for commercial trawling activities is around 2 to 4 knots. The designed protective structure is able to withstand that amount of impact up to the safety factor of 3. The protective structure also equipped with the to resist trawling gear from fishing activities.