Conrie Field Development Environmental Statement - Metoc

ENQUEST DONS LTD
CONRIE FIELD DEVELOPMENT
8.3.3 Potential Impact Identification
The EIA identified that during the project life cycle the activities presented in
Table 8-7 have the potential to interact with fish, shellfish and elasmobranchs.
Table 8-7: Fish and shellfish - potential impact identification
Project Activity Aspect Potential Impact
Construction
Drilling of wells
Discharge of chemicals
Potential toxic effects.
Tie-in of wells
Well test
Discharge of residual reservoir
Physical presence and movements of
vessels
Physical presence and movements of
vessels
hydrocarbons
Discharge of sewage, grey water,
food waste & drainage water
Anchoring
Organic enrichment leading
to raised biological oxygen
demand. May increase
plankton & fish populations
changing balance of food
chain.
Smothering
Loss of spawning / nursery
grounds
Physical damage to
individuals
Drilling of wells
Discharge of cuttings
Tie-in of wells
Concrete mattressing and grout
bags
Presence of wellheads
Drilling of wells
Subsea noise
Damage to eggs and larvae
Tie-in of wells
Production
Produced water Discharge of reservoir hydrocarbons Potential toxic effects.
Northern Producer maintenance
Discharge of chemicals
Accidental Events
Release of hydrocarbons (10 tonnes)
Accidental overboard spill during handling,
storage or rough weather
Spill of chemicals, oil or diesel.
which may affect
recruitment and stock
viability.
Overboard loss of equipment or waste Dropped objects Smothering and damage to
benthic species
Potential impacts that require mitigation fall into two categories:
Those that could have toxic effects and
Those that disturb the seabed causing loss of habitat and
spawning/nursery grounds.
The majority of activities have been assessed as possibly having an impact on
fish communities. The spatial extents of the impacts range from local to
extensive (for accidental events). The significance will be insignificant to minor.
The residual impact significance of the impacts has been assessed in Section
G of Appendices A.2-A.4.
8.3.4 Mitigation Measures
Measures to mitigate deterioration in water quality and toxic effects of
chemicals have previously been outlined in Section 7.3.4, whilst measures to
minimise physical disturbance to the seabed are discussed in Section 7.4.4.
REPORT REFERENCE: P1534_RN2574_REV1_S7-8 8-12 18/04/2011