Evaluation of Extreme Conditions for Transportation of Offshore Drilling Equipment Using Riser Column

Resumo

Considering the increase in offshore production activities taking place in deep water depths, the
operations related to well drilling and oil production are becoming more complex and expensive and demands
detailed analysis to assess the safety of the procedures. An example is the transportation of equipment with large
dimensions such as the Blow-Out Preventer (BOP) and Lower Marine Riser Package (LMRP) pack, which is a
procedure that needs attention since it is costly and demands a lot of time due to deep water depths at which this
equipment is being installed. In addition, the pack can reach resonance zones during the installation procedure,
increasing the relevance of dynamic analyses. In this context, the objective of this paper is to study the feasibility
of transporting the BOP/LMRP without the need to withdraw the equipment to the drilling rig, which, in some
cases, should considerably reduce the time and cost of the operation. In addition, the work addresses the main
forces acting on the drilling riser during this procedure and the need to perform specific analyses. Typical
equipment will be studied at three different depths considering different navigation speeds and wave heights.
Criteria such as maximum stress and limit angle of the lower flexjoint are evaluated. Although the wave and Vortex
Induced Vibration (VIV) fatigue phenomena have not been studied, the main goal is to assess whether extreme
efforts are points of attention in transport operations with the BOP/LMRP set suspended.