The study was conducted to improve knowledge and provide guidance on reducing uncertainty with impact predictions when drilling near sensitive environments. Near/Far-field hindcast modelling of cuttings/drilling fluid (mud) discharges from a floating platform was conducted, based on measured discharge amounts and durations and validated by ROV-based plume and seabed sampling. The high volume, concentration, and discharge rate water-based drilling mud discharges (mud pit dumps) were identified as the most significant dispersal risk, but longer-range movement was limited by the generation of jet-like plumes on release, which rapidly delivered muds to the seabed (80 m). Effects to the sparse benthic filter feeder communities close to the wells were observed, but no effects were seen on the epibenthic or demersal fish assemblages across the nearby mesophotic reef. For future drilling near sensitive environments, the study emphasized the need to better characterise drilling fluid discharges (volumes/discharge rates) to reduce uncertainty in modelling outputs.

Depth range
0- 80 m

Mesophotic “mentions”
9 x (total of 17235 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range
* Focused on 'mesophotic coral ecosystem'

Fields
Disturbances

Focusgroups
Overall benthic (groups)

Locations
Australia - Western Australia

Platforms
Baited Remote Underwater Video (BRUV)
Remotely Operated Vehicle (ROV)
Surface-deployed sensors and samplers