In Greek mythology, Oceanid's are the sea-nymphs who were the three thousand daughters of the Titans Oceanus and Tethys. It represents a truly disruptive technology and the next generation seismic OBN – ocean bottom node, an autonomous drop-node purely propelled by gravity and ballast shift.
The foremost motivation for deploying numerous seismic sensors to the ocean floor, is to get a better understanding of the sub-bottom geology and reservoir geomechanics, and implicit reduce the risk when performing costly exploration-drilling or gain from optimizing the production license. However, due to the historical high installation cost and unfavourable technical downtime, this method traditionally only account for a fraction of the overall seismic market. Hence the key to unlock the potential, and provide a service commonly available, is to achieve a reduced investment- and operation cost and greatly improve the equipment reliability. While at the same time provide a scalable-, and flexible sensor network of superior data quality.
The node Oceanid™ and further the ‘Oceanid-6C’ comprises two distinct sub-systems – the ‘flight control’, and the ‘data acquisition’, but the two overlap with regards to mechanical integration, power management, data-storage and external communication.
One operational configuration is to launch a typical batch of 9 nodes from an over-boarding, and subsequently submerged basket, only a few meters below the sea surface. The nodes are pre-programmed to self-navigate to individually unique locations on the seafloor, collectively creating a pre-defined sensor grid, purely based on last known surface GPS-position, the navigation sensors and the onboard navigation algorithm. Upon safe landing, the node will self-align to gravity-vertical, plant- and release the seismic payload. Upon release of nodes the basket is recovered onboard, re-loaded and batches of new node deployed until full recording sensor coverage, and seismic survey can commence.
Once the full azimuth source pattern-coverage is completed, part of the actual seismic survey or swath, the node will communicate hydro-acoustically with the surface, receive an updated pickup location and hence recalculate the return-trajectory prior to release, i.e. retrieve payload sensor, re-fold the landing gear and drop the salt-ballast. Due to net positive buoyancy, the node will self-propel itself to the surface, where a self-erecting antenna will broadcast over VHF or Wi-Fi the unique node id with its received GPS-position, and activate a LED-strobe for visual identification.
An automated recovery system onboard will retrieve the nodes out of the water, tap logged data and prepare node for re-launch in a batch-roll multi vessel operation, or recover all in the case off only one vessel deployment. Both the deployment- and recovery system, incl. onboard node storage, to be fully containerized and automated.
The overall system- and service provided as a project outcome will facilitate a disruptive efficiency in All future harvesting of sensor data from the ocean bottom or in the vertical water-column, providing a generic tool for a variety of survey purposes, flexible in size- and configuration of node grid not constrained to shallow water nor by cost.
Utilizing a fleet of locally available support-vessels our containerized spread may be shipped globally and operated by a combination of local crew and super-users from within the service organization.
