Monitoring Campaign on Sub-Sea Installation

The Deepwater Construction Vessel (DCV) Balder performed an one-and-half year deep water construction project in west Africa. The project started in 2010 and consists of multiple oil fields located in water depths ranging from 1800m to 2100m. Heerema Marine Contractors (the Contractor) has successfully installed a large number of sub-sea structures, flow lines and Risers. Installation procedures were optimized, new deck equipment has been installed and passive heave compensation is designed. These measures enabled the crew to achieve an excellent performance in the swell dominated seas West of Africa. To accurately capture the experiences with the new equipment and procedures, an extensive Offshore Monitoring Campaign (OMC) was performed. To achieve this goal three areas of interest were identified: • Lowering structures to the seabed at deepwater • Offloading of barges alongside the DCV Balder • Motion behavior of DCV Balder in swell environment The objectives of the monitoring campaign were: • Validation of the models and performance of the equipment • Verification of the operability limits for different installation activities • Transfer of knowledge between engineering and operations The paper describes how the Contractor executed the different measurements and how the results from the measurements were fed back into the execution of the project. The challenges which were faced to obtain high quality measurement data will be dealt with. Finally it shows the benefits of performing full-scale measurement to engineer safe and efficient deep water operations.