Presently, drilling riser joints are inspected every five years. This is usually accomplished by rotating 20% onshore every year to be dis-assembled and inspected. This requires extensive boat trips from a mobile operating drilling unit (MODU) to onshore and trucking of the riser to the inspection facility. Typically, 20 riser joints from each riser system are transported on a boat and one riser per truck to an inspection facility each year, making the logistics of performing a drilling inspection complex and costly.
A laser-based measurement for inspection together with monitoring of riser systems has been implemented with a new standard process for collecting critical riser data that is ABS approved. The aim is to mitigate the costs and time associated with essential MODU drilling riser inspections, by empowering operators to reliably determine the condition of drilling riser joints, consistently predict when vital components will require service and accurately assess remaining component life.
The approach utilizes a life cycle condition based monitoring, maintenance and inspection system that can be deployed on a MODU, enabling resources to be deployed only when necessary, instead of on a calendar interval. The solution consists of: Performing a baseline inspection on the riser joints to assess their present state, Collecting the environmental and operating data when the rig is on site drilling, Feeding the environmental and operating data into a digital twin. The tuned digital twin can be used to predict future damage.
The approach removes uncertainties surrounding damage of riser joints and will allow the owner to determine whether riser should be redeployed or replaced. This is the only process that is ABS approved for condition based monitoring of drilling riser systems. The system is compatible with all present owners’ maintenance programs and ensures that maintenance requirements are supported with robust engineering.