Long-range ADCP deployment supports offshore installations in Trinidad and Tobago

The often threatening current and wave conditions off the east coast of Trinidad – the North Brazil Current Rings – can be strong and can affect rig moves, drilling operations and riser designs. Why did environmental consulting firm Coastal Dynamics Limited choose Nortek instruments when they needed to observe these conditions?

User stories

4 minutes

Synopsis

Challenge

Strong currents and waves off the coat of Trinidad can threaten offshore energy operations, making reliable numerical modeling and monitoring crucial.

Solution

Environmental consulting group Coastal Dynamics used a Nortek Signature 55 and AWAC to collect long-range current profiles as well as wave data from a subsurface buoy.

Benefit

The data improve operational efficiency and environmental assessments in the area.

Recently a renowned energy company contracted environmental consulting firm Coastal Dynamics Limited to obtain reliable current and directional wave data to improve their numerical models.

These data were also important in investigating environmental conditions that adversely affect drilling operations. It was essential to incorporate these into project planning.

Setting up a functional solution

Here, Coastal Dynamics Limited chose Nortek’s Signature 55 to collect high-resolution current data in the water column, as well as the Nortek AWAC with patented SUV wave processing for near-surface currents and directional waves. Both are robust systems, optimized for operational users, which also produce scientific quality data.

“In this project, Nortek provided us with a complete solution: from the sourcing of acoustic releases and flotation to important contact with mooring experts to advise on all details for the mooring,” says Nazeer Gopaul, Director at Coastal Dynamics Limited in Trinidad and Tobago.

Coastal Dynamics Limited was able to satisfy the specific needs of their client by placing a higher-frequency AWAC near the sea surface and an Aquadopp Profiler down-looking in the near-bed Signature 55 buoy to observe waves, near-surface currents, and bottom conditions. Most users often give up measuring currents close to the surface and bottom due to operational and instrument limitations. But Nortek’s form factor and patented data processing of the Aquadopp Profiler and AWAC allowed them to easily capture this often missed data for their client.

“We were able to collect high-resolution water column [current] profiles, which not only provided excellent information for our client but simultaneously gathered very useful scientific data that could be used to glean further information on a previously undocumented water column structure,” says Nazeer Gopaul.

“The deployment was successful and the data gathered from the field campaign provided excellent data quality for our study,” Gopaul adds.

Coastal Dynamics Limited chose Nortek’s Signature 55 to collect high-resolution current data in the water column off the coast of Trinidad.

A reliable system delivering high-quality data

The Signature 55 is a dual-frequency, broadband instrument. This means that the user may select 75 kHz, 55 kHz, or alternate both, providing highresolution measurements near the instrument, and larger cell average currents out to > 1000 m.

The dual-frequency nature of the instrument is inherent to all Signature 55 systems, so users do not have to choose which frequency to use at time of purchase. This gives users the flexibility to adapt to different conditions based on the project at hand.

In this shallower location (~400 m), Coastal Dynamics Limited opted to utilize only the 75 kHz mode, taking advantage of the high-resolution data at incredibly low power.

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“The Ethernet connection allows us to download data rapidly so that we can deploy on tight schedules in deeper water deployments. We are also able to obtain full water column profiles with highresolution data that can then be used for several applications such as dispersion studies, environmental assessments, operational oceanography and research,” Nazeer Gopaul explains.

The mechanical design of the Signature 55 is suitable for applications on platforms, drilling rigs, bottom frames and subsurface buoys.

The elliptical shape of the Nortek subsurface buoy minimizes the drag and an integrated frame holds the instrument in place. The instrument can also be placed on bottom-mounted frames. This means that users are not dependent on structures on the surface to perform measurements – offering greater flexibility, and a wider area of use.

Color contour plot showing current data (as a function of depth and time) from a deployment off the coast of Trinidad. A ring current spinning off the North Brazil Current (and impacting the project area) was clearly visible in the data.

Winning projects and expanding capabilities through knowledge sharing

Nazeer Gopaul emphasizes that Nortek’s willingness to share technical knowledge and assist his organization in making decisions has helped Coastal Dynamics Limited win projects for deployments in deeper waters.

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“We are now exclusively using Nortek ADCPs mainly because of the extensive support we receive and the connections to Nortek’s partners. The referrals and contacts we establish through Nortek have allowed us to offer our clients the best available technology while being cost-effective,” Nazeer Gopaul adds.