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Condition Based Maintenance of Drilling Risers

Drilling rig maintenance is essential, but capital-intensive. Current regulations require that all drilling risers be inspected every five years—a costly and time-consuming process for operators. Over time, environmental conditions create stresses in drilling riser systems, the critical conduits between rigs and well systems. These conditions lead to fatigue and corrosion in the drilling riser joints.

The typical process for drilling riser inspection is complex. Risers must be disassembled on the mobile operating drilling unit, carried onshore by barges, then transferred to trucks, where they are driven to an inspection facility, incurring significant cost for the operator.

Stress Engineering Services, in partnership with LaserStream, has developed a first-of-its kind maintenance and inspection system using life cycle condition based monitoring that can be conducted on-site. It’s the only condition based monitoring system currently certified by the American Bureau of Shipping.

This system consists of a multi-step process. First, a baseline inspection is performed with a tethered crawler on the riser joints using LaserStream’s BEMIS™ inspection system.

This environmental and operating data is fed into a digital twin, a virtual replica of the mobile operating drilling unit and drilling riser system. The digital twin is then calibrated by actual riser load measurements from a subsea vibration data logger, giving operators the ability to perform targeted inspections.

Once tuned, the digital twin can be used to predict the damage state for the riser and rig over time. By better understanding wear rates and riser damage, operators can make informed, cost-saving decisions on repair or replacement of components—regardless of calendar interval.

Understanding and mitigating risk—without having to leave the mobile operating drilling unit—saves time, cost, and resources while giving operators unparalleled insight into the life cycle of their essential equipment.