Environmental statement - Flyndre and Cawdor - Maersk Oil
Environmental statement - Flyndre and Cawdor - Maersk Oil
Environmental statement - Flyndre and Cawdor - Maersk Oil
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Installation Phase<br />
<strong>Environmental</strong><br />
Aspect<br />
Greenhouse<br />
gases/ Air<br />
emissions<br />
Discharges to<br />
Sea<br />
Source<br />
Exhaust<br />
emissions<br />
associated with<br />
support vessels<br />
<strong>and</strong> installation<br />
of subsea<br />
infrastructure<br />
e.g. infield<br />
pipelines,<br />
manifolds, SSIV,<br />
concrete<br />
mattresses <strong>and</strong><br />
rock placement.<br />
Discharge from<br />
pipeline pressure<br />
testing.<br />
Discharge of fluid<br />
from the open<br />
subsea control<br />
Activity<br />
Description<br />
Subsea wellheads will be<br />
fixed in position on the<br />
seabed surface. All<br />
infield pipelines <strong>and</strong><br />
control lines will be<br />
trenched. This operation<br />
will require a trenching<br />
vessel with associated<br />
exhaust emissions. A<br />
separate vessel will<br />
complete the rock<br />
dumping if required.<br />
After installation<br />
pipelines need to be<br />
pressure tested. The<br />
lines are to be filled with<br />
potable water, dosed<br />
with methanol, & scale,<br />
corrosion <strong>and</strong> wax<br />
inhibitors. The displaced<br />
water, <strong>and</strong> chemical<br />
additives will be<br />
discharged to the sea<br />
Hydraulic control of<br />
subsea facilities.<br />
Control systems use<br />
Potential effects <strong>and</strong> significance of potential<br />
impacts<br />
May contribute to climate change (CH4, CO2),<br />
acidification effects (SOx, NOx) <strong>and</strong> potentially<br />
localised smog formation (VOC, NOx &<br />
particulates).<br />
Likelihood Consequence Risk<br />
5 1 Low<br />
Localised effect on water quality associated with<br />
discharge to sea of water containing chemicals<br />
from hydrotesting of lines.<br />
Likelihood Consequence Risk<br />
5 1 Low<br />
In an open system fluids will be released to sea<br />
with resultant short term effects on local flora<br />
<strong>and</strong> fauna.<br />
<strong>Flyndre</strong> <strong>and</strong> <strong>Cawdor</strong> Development <strong>Environmental</strong> Statement<br />
Appendix B – <strong>Environmental</strong> Impact Assessment<br />
Mitigation of impacts <strong>and</strong><br />
actions to address<br />
concerns<br />
Minimise duration of<br />
pipeline trenching <strong>and</strong> rock<br />
placement operations.<br />
All chemicals will be risk<br />
assessed as part of<br />
Offshore Chemical<br />
Regulations requirements<br />
<strong>and</strong> reported in PON 15C.<br />
Discharge of fluids, if<br />
required, will be carried<br />
out in a manner which will<br />
minimise environmental<br />
impact.<br />
Only PLONOR chemicals<br />
will be added to the water<br />
based hydraulic fluids.<br />
Residual impact<br />
<strong>and</strong>/or concern<br />
None envisaged as<br />
contribution of<br />
emissions to<br />
worldwide levels is<br />
negligible when<br />
compared to other<br />
industrial sources.<br />
None envisaged.<br />
Rapid dispersion <strong>and</strong><br />
dilution will occur in<br />
close proximity to<br />
the discharge point.<br />
None envisaged.<br />
B ‐ 8 D/4114/2011
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