Water column monitoring equipment: Enhancing offshore spill response and scientific sampling
About the water column monitoring equipment
The WCM Equipment was developed by CSA Ocean Sciences Inc. (CSA) and has been integrated into operational plans and desktop exercises conducted in the U.S. and internationally since 2014. CSA is a marine environmental consulting firm with 50 years of experience serving the environmental needs of the offshore oil and gas industry. The WCM Equipment is offered through the OSRL SWIS Capping subscription to complement existing equipment designed for the use of SSDI as a response option when relevant. Even if SSDI is not required as a response option, the WCM Equipment provides useful instrumentation and tools to enable sampling and monitoring in deep-water settings for Operational and Scientific Monitoring Plans (OSMP).
Equipment overview and capabilities
Designed for mobilisation on an offshore supply vessel, the WCM Equipment includes two 8 ft × 20 ft containers certified for offshore use by Det Norske Veritas (DNV) and the American Bureau of Shipping, powered during stand-by, and functioning as shipboard workspaces during deployment. The equipment in each container enables in situ sampling and monitoring in water depths up to 3,000 metres and provides real time in-situ data collection of subsurface water quality, which can be used to characterise the extent and limits of subsurface oil, and to monitor the efficacy of subsea dispersant.
Launch and recovery system
The WCM Equipment is self-contained and mobilisation-ready, with an integrated Launch and Recovery System (LARS) consisting of a 30-horsepower winch, A-frame and skid (DNV certified by Lloyd’s post-construction). The system is equipped with an electrotechnical cable to provide power and communication to the sensor and sampling equipment.
Sampling and sensor instrumentation
In-situ sampling and monitoring of the water column characteristics is achieved through:
- Carousel equipped Teflon-lined GO-FLO bottles that can be remotely triggered at any depth to collect water samples for laboratory analysis;
- Screening of water samples for volatile compounds using a mobile gas chromatograph/mass spectrometer (GCMS); and
- Samples stored in commercial grade, under-counter refrigeration units or Sub -80°C freezer unit until shipment to a shore-based laboratory for analysis.
Water sampler rosette
Water column characteristics are measured with depth to generate hydrographic profiles. This is achieved through the following instruments:
- Conductivity Pressure Depth (CTD) Profiler
- Dissolved Oxygen Sensor
- Fluorometers (2 sensors: CDOM and ECO-FLNTU)
- Coloured Dissolved Organic Matter (CDOM) allows you to obtain CDOM fluorescence across a wide range of environments, from mangrove swamps to oligotrophic blue water
- ECO- FLNTU Combines an Environmental Characterization Optics (ECO) fluorometer with an optical scattering measurement for simultaneous determination of turbidity.
Other instrumentation to analyse particle size includes the LISST-Deep and LISST-100X. Both are laser diffraction devices that operate on the same premise of light scattering; however, the LISST-Deep is rated for water depths up to 3000 metres, whereas the LISST 100 X is rated for waters up to 300 metres.
Additional safety and operational features
Additional features of the WCM Equipment are designed for worker safety and to enable required equipment and spares to be available on stand-by and mobilisation-ready. These include:
- HD video system for integration with ROV
- Portable air monitoring devices for monitoring VOC’s
- Work Van smoke and heat detectors
- Horn and strobe detectors
- Marine and General Alarms
- Oxygen sensors and alarms
- Portable radios for communications
- Fire extinguishers and Spill Kits
- First Aid Kits and Automated External Defibrillators
- Personal Protective Equipment
- Chemicals, consumables, and supplies for an initial two-week deployment
