The Problem
Traditionally, the inspection and recertification of moorings on MODU facilities required the relocation of the facility to a dry-dock “on the beach.”
This is an expensive procedure because it leads to drilling downtime, dry-dock costs and ongoing leasing costs associated with drilling rig contracts.
It is also time-consuming due to transportation of the MODU to and from the beach.
In addition, there is extra risk involved with moving offshore facilities over distances.
The Solution
A Gulf-of-Mexico based drilling company identified these problems and approached Welaptega Marine with a requirement to inspect the moorings while the MODU facility was on station, or as part of a scheduled rig move.
Welaptega partnered with the driller and DNV to design a mooring inspection program to be conducted on board the rig.
This solution was designed to meet compliance requirements by DNV and provide the driller with an in-situ inspection solution that yielded significant time- and cost-savings because the rig did not have to be relocated for inspection.
In-situ inspections
The in-service inspection and recertification technique yields lower costs, faster results and reduced production downtime.
Because in-service inspections are conducted on the MODU facility, it eliminates the need to transport equipment and personnel to a dry-dock location. It also reduces risks associated with transportation to dry-dock and mooring system removal.
The inspection can be conducted as the unit is drilling or as part of a scheduled rig move.
This enables the drilling contractor to maximize drill time and avoid contractual implications of elevated downtime or moving off station.
The Welaptega technique
In general, Welaptega’s inspection methods are largely video based, providing a permanent record that can be reviewed after inspection by the class society or other technical authorities.
In-service MODU inspections are designed according to the mooring spread, type of rig, and the classification requirement for the MODU.
Welaptega’s inspection capabilities include chain, wire rope and fibre rope.
The data obtained from inspection is used to inform operational decisions on assets.
The technique is a rugged inspection procedure with permanent visual records and quantified data set. This enhances the inspection program, ensuring consistency of results between sites, projects and teams.
In-situ inspection allows chains to be measured under tension, producing more accurate results for link elongation. Wire ropes are also measured under tension either while installed or during pull-in.
Inspecting mooring systems in-situ reduces the inherent risk associated with moving mooring lines (unspooling wire, chain winching operations, etc).
The Welaptega approach can be performed in real-time as part of a standard rig move, with minimal downtime to the mooring deployment/retrieval process.
This technique reduces the time and cost associated with traditional inspection methods.