"justify">. Support to electrical diagnosis and trouble shooting / fault finding
. Assistance to large module replacement
. Disconnection of lying leads
. Fluid and thermal leak detection
. Subsea sampling
. Replacement of small components
. Any other ROV operation requiring only the use of manipulators or manipulator carried tools. The Swimmer AUV can be programmed for field survey and pipeline inspection tasks such as the following:
. Field mapping
. Pipeline survey
. Pipeline close visual inspection
. Pipeline free span detection
. Pipeline localization
. Dropped objects detection
. Cathodic protection measurement.hybrid Swimmer vehicle combines ROV-borne IMR capabilities, suitable for maintaining SPS within tether range from the docking stations, with AUV-borne inspection capabilities for survey and inspection of subsea flow lines. Together, the scope of tasks covers the needs for all light IMR operations necessary to maintain a facility in production except replacement of large modules. The tools for IMR tasks on an SPS are generally small and can be embarked directly by the light Work-ROV, or alternatively put into storage compartments onboard the AUV shuttle.
Some tools do not yet satisfy the requirements of the Swimmer system, particularly on long deployments. These include:
1. Tools requiring calibration (eg torque tool) prior to use. These calibrations currently are done at the surface. Because the Swimmer system can remain subsea for an extended duration, and because the calibration preferably should be performed just before the operation, and suitable marine-grade devices will be needed.
. Seabed sampling is of interest for applications such as multiphase flow meter calibration, monitoring of oil-in-water and sand-in-water prior to reinjection, fiscal allocation, and reservoir monitoring for enhanced oil recovery programs.
. Hydraulic tools are not ideal for long duration subsea use, so all-electric equivalents should be developed (eg torque tool, brush, manipulator). Inspection of flow lines and cables, or general field survey, can be conducted from an AUV shuttle equipped with the guidance and data acquisition packages. The vehicle will autonomously follow its targeted path (eg a production flow line on the seabed), and record all relevant data on local storage devices for later analysis. After mission completion and return of the AUV to docking, data files are uploaded and the results analyzed offline. Because the operator is not in the loop during the survey, an AUV-based inspection is less reactive than with an ROV. However, its cost is lower and independent of the weather. Plus, the inspection may be repeated and modified for closer inspection if key points of interest were detected during the first survey. The DP - 2 surface vessel is the main cost of conventional IMR. A key of the Swimmer is that it only requires a surface vessel for launch and recovery. The vessel can be released after the AUV has docked subsea. To further minimize MSV use and optimize ope...
