A model suited for control tasks is developed for a submerged offshore pipe during the pipelay operation. The pipe is fixed in the touchdown point at the seabed in one end and attached to a pipelay vessel in the other end. The developed model is discrete and is on the form of the robot equation with minimal coordinates. Thus the methods of controller synthesis and stability analysis can be appl...

Introduction When it comes to a fast, non-intrusive, complete and meaningful inspection of an offshore pipeline in-line inspection (ILI) has been the method of choice for several decades now. However, not all pipelines, piping or other tubular structures can be inspected with in-line inspection tools (pigs). The method is usually limited to looping flow lines or export pipelines, specifically d...

Dropped objects from cranes are one of the most hazardous events during the operation of the topside of offshore plants along with hydrocarbon gas explosion and fire. Although it is strongly suggested by international rules and regulations to evaluate probabilistic impact risk from dropped objects in the offshore industry, most engineers have had difficulties in estimating a reliable risk value...

Riser emergency shutdown valves (RESDVs) are an essential risk reduction measure for offshore installations and are a legal requirement under the Pipelines Safety Regulations 1996. The RESDV should isolate the topsides from the well and subsea pipeline in the event of an emergency shutdown, to reduce the inventory for loss of containment or when required for maintenance. RESDV failures, whether...

Fault Tree Analysis (FTA) as a Probabilistic Risk Assessment (PRA) method is used to identify basic causes leading to an undesired event, to represent logical relation of these basic causes in leading to the event, and finally to calculate the probability of occurrence of this event. To conduct a quantitative FTA, one needs a fault tree along with failure data of the Basic Events (BEs). Sometim...