Periodic Reporting for period 2 - Oceanid (Large-scale piloting and market maturation of a disruptive technology comprising a fully automatic survey system dramatically reducing the operational cost of handling swarms of autonomous sensornodes)
Reporting period: 2017-05-01 to 2018-08-31
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.
Below a short list of improvements and achievements:
complete system - from pre-dive to post-dive
Pressure-tolerant, typ. 300bar
Increased operation, 120-180days
Improved vehicle design:
Reduced size, Ø325x1250mm
Containerized storage and handling, e.g. 250 nodes per 20-foot (High Cube) container
Low production cost, e.g. molding and casting
Acoustic-navigation and positioning capacity*
Improved seismic sensor and data logging
Implemented recovery antenna, incl. “AIS” and LED-strobe
The former generation Mk.I of the vehicle is reduced by appr. 30%. Within this envelope the acoustics is improved, handling implemented and a new hull-design established.
The first prototype is tested in a tank-facility in Italy, confirming the hydrodynamics, and landing of the vehicle on the bottom. A scaled down version of the handling is tested with induced waves etc.
In parallel to further testing this design is improved and a new set of prototypes (Mk.II r2) is being produced, incl. new ballast-tanks (to be blow molded in a final production modus). This version will be piloted later this summer/early autumn, in parallel to further design improvements and system integration, e.g. a new sensor-concept is prepared for. End-client feedback is currently being processed and will be implemented in the large-scale production run (Mk.II r3) and piloting.
The latter may prove significant due to a positive effect on operation duration, reducing the amount of source-points to cover the same survey area, (or reduce the number of receiver-points). The project has been approached by the NOC Statoil ASA R&D, and signed an LoI for the joint development of a new concept establishing the complete pressure-field around the vehicle, when installed on the seafloor. This will allow reconstruction of source- or receiver-points through interpolation- and integration of a sparse sensor-grid. This will reduce the environmental impact, less use of source, i.e. less sailing along source-lines, and a more rapid overall survey duration.
Equally important is a novel underwater navigation- and positioning concept utilizing the large grid of vehicles operating as a swarm, greatly improving positioning accuracy, communication of navigation data at a fraction of the power-consumption previously needed for transmitting acoustic sound in water. A target at seafloor positioning accuracy is re-defined to Rdms2,5M, without the need for the topside support vessel having to use additional time for acoustic transmission, but rather utilize the time when vehicles is released from a submerged basket over the stern of the vessel. The reduced environmental impact will be significant primarily by reduced underwater communication /-noise, but also faster operation and less hovering with the support vessel.
*(Initial contact is made with another H2020-project, 'SWARMs', tentatively looking at synergy effect and complementary services).