Nigeria is a country of vast natural oil and gas reserves. In order to maximize the production and export of these gas reserves, Nigeria LNG Limited (NLNG) has established its LNG Plant on the western coast of Bonny Island, approximately 40 km south of Port Harcourt, Nigeria. In order to expand the current capacity of this facility and to accommodate more and larger LNG carriers, NLNG appointed its Technical Advisor, Shell Gas Nigeria B.V., to commission a complete technical, environmental and metocean study of the riverine and off-shore area. The results of these studies will be used as the basis for the widening and deepening of the approach channel, which will remove the current tidal restrictions. The field work to facilitate this comprises several distinct measurement programs, including:

• physical and chemical characteristics of the seabed,
• physical, chemical and biological characteristics of the water column,
• benthos (animals and plants living in and on the seabed),
• metocean conditions, particularly current profile, turbidity and tide measurements in the Bonny and New Calabar Rivers, and
• current profile transects along 4 lines within the rivers and tide measurements at the LNG / LPG terminal.

In July, MSI mobilised the metocean component of the project. Equipment and personnel were mobilised to Onne Port (Port Harcourt) to join the vessel R/V GeoExplorer, owned and operated by TDI-Brooks, Inc who are undertaking all other components of the study. For the current transects, MSI installed an RD Instruments 600kHz acoustic doppler current profiler (ADCP) deployed on a pole through the vessel’s moon pool and the data was displayed in real-time and logged onto a pc in the navigation room.

Once the current transects were completed, two trawl resistant seabed frames were assembled and into each was fitted a 600kHz ADCP and Valeport CTD probe with turbidity sensor. The frames were then deployed, one in each of the Bonny and New Calabar Rivers.

Finally, a Valeport 710 tide gauge was deployed on the LNG / LPG jetty and surveyed in to the local datum. The project commenced in June this year and is expected to be completed in the first quarter of 2005.

For more information on this or other projects conducted by MSI, please contact us.