Environmental Statement - Maersk Oil

Balloch Field Development Environmental Statement
Section 5 Assessment of Potential Impacts and Controls
Well heads and X‐mas Trees
Table 5‐6 Total seabed footprint from subsea infrastructure.
Requirement Number 1 Dimensions (L x W) (m)
Total Footprint
(m 2 )
Protective structures 3 3 x 3 27
Jumpers 2
6 ” production 3 80 x 0.45 108
6 ” production (rated to 100 o C) 3 80 x 0.45 108
3 ” lift gas 6 80 x 0.45 216
Well set (chemical and controls) 3 80 x 0.45 108
Control umbilical 3 80 x 0.45 108
Tie‐in Spools 3
Production 3 20 x 0.45 27
Lift gas 3 20 x 0.45 27
Cooling Spools
Cooling spool (maximum temperature 80 o C to DC2) 2 6 x 6 72
Total 801
1 Number of structures assumes three production wells.
2 For all jumpers, widths of 0.45 m have been assumed.
3 For all tie‐in spools, lengths of 20 m and widths of 0.45 m have been assumed.
Subsea infrastructure will be submitted for inclusion on the Admiralty Charts so that it may be
identified by fishing vessels. It will also be entered into the FishSafe database, an industry‐sponsored
computer system linked to vessel navigation systems that improves the ability to detect, identify and
avoid potential hazards.
As the benthic organisms likely to be impacted by the proposed development tend to have rapid
reproductive cycles and widespread distributions, the impact caused by the physical presence of the
infrastructure is not considered significant. In addition, as a result of the proposed notification
measures the impacts on other sea users is considered low.
Mattresses and grout bags
The subsea infrastructure will be surface laid and will required some degree of protection; it is
anticipated that a total of 30 mattresses and 15 grout bags will be used should the three production
wells be required (Table 5‐7). The maximum footprint of these protective structures is 0.0005 km 2 .
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