Enviros performed a scope of work to assist Total (primary client) in the evaluation of the seabed and sub-seabed conditions. This included the potential associated geohazards or other manmade hazards affecting the approach and installation of a jack-up rig drilling unit and its subsequent drilling operations.
To achieve the client objectives Enviros measured the water depth and slope variations within the survey area and estabilshed the morphology and nature of seabed, as well as investigating the underlying shallow geology. An evaluation of any shallow hazards such as slope instability or wrecks within the upper tens of meters was completed. Finally, an investigation to locate any natural or man-made seabed or buried obstruction such as, but not limited to, rock outcrops, escarpments, channels, reefs, depressions, debris (natural or man-made), wrecks, industrial structures, pipelines, cables, etc, was completed.
Equipment used to follow out the objectives included:
- Multibeam Echosounder /Single Beam – R2Sonic 2022/ Knudsen 3260 with 210kHz SBES transducer;
- 2DHR – GeoEel Silicone 96 channel streamer and 4x40cu.in Sleeve TI Source;
- Sub-Bottom Profiler - 4 x 4 Neptune T335 transducer array with Knudsen 3260 CHIRP Recorder;
- Sparker - Geo-Spark 200 with Geo-Spark 1kJ Energy Source;
- Side Scan Sonar - Edgetech 4200;
- Magnetometer – Geometrics G882;
- USBL – Sonardyne Ranger 2;
- 6m Gravity Corer for sampling;
- Optional Box Corer and Van Veen Grab Sampler.
Project Organisation
Enviros were responsible for performance of all pre-mobilisation, mobilisation, fieldwork, demobilisation and associated data processing, interpretation and reporting. A senior Enviros Project Manager with >15 years relevant offshore site survey / investigation experience was appointed on contract award and responsible for each project phase and Client liaisons throughout. The Enviros Project Manager was appointed an experienced Enviros Offshore Project Manager for all fieldwork operations.
The Project Manager had the role of managing day-to-day issues relating to the project, based onshore in the Enviros head office based in United Kingdom. The Offshore Project Manager was responsible to ensuring that the project is completed in accordance with Enviros procedures and to Client specifications. Responsibilities include, but not limited to being the immediate point of contact for any Offshore Client Representatives, ensuring project QHSSE procedures are adhered to during all offshore operations; this is to include mobilisation, field calibrations and checks, project tasks, post project calibration checks and demobilisation; and the production or approval of all necessary field reporting.
