Kongsberg Maritime developed a system for measuring ocean currents along drilling risers. The data can be integrated with the Kongsberg HiPAP positioning system to improve control of drilling operations.
The new system consists of a Nortek Aquadopp single-point current meter connected to a telemetry transponder that sends 3D velocity data to a surface modem via an acoustic link. A number of current meters can be placed on a single rig, ensuring that drilling teams are able to receive accurate current data from as wide an area as required.
Transponder interfaced to a 3000 m Aquadopp.
The Kongsberg Maritime team accounted for the fact that sending sea current telemetry takes time, which influences the HiPAP update rates. However, the ocean current does not change over short time scales, so the Aquadopp update rate can be set anywhere from five to 30 minutes. Should HiPAP be used as a dynamic positioning reference system, integrating Kongsberg Maritime’s HAIN reference system will maintain the update rate at one ping per second.