Environmental statement - Flyndre and Cawdor - Maersk Oil

More documents

Recommendations

Info

5‐ 20 Flyndre and Cawdor Environmental Statement Section 5 Assessment of Potential Impacts and Control Measures OIL DISCHARGED WITH PRODUCED WATER In order calculate the maximum weight of oil discharged with the PW a discharge quality in line with regulatory requirements of 30mg/l oil in water content was used Table 5‐12 shows the maximum dispersed oil associated with the PW from the Flyndre and Cawdor development. During 2009 2,900 tonnes of oil was discharged with PW from offshore installations on the UKCS. A maximum additional annual discharge of 10.95 tonnes (based on 2026 PW production profiles for the Flyndre and Cawdor development) constitutes a relatively small increase (0.38%) of the existing oil in water discharges to sea from installations on the UKCS. As such the impact associated with the increased discharges is not anticipated to be significant. Source Dispersed oil associated with maximum PW production (2026) from Flyndre and Cawdor development Annual produced oil discharged (te) Produced oil discharged (te/d) 10.95 2 0.03 2009 UKCS dispersed oil in PW discharged 2,900 1 7.9 As a % of UKCS total 0.38 0.38 1 Source; DECC (2011). 2 based on 2026 maximum PW production profiles from Flyndre and Cawdor development and assuming maximum oil in water content of 30mg/l. Table 5‐12 Dispersed oil associated with maximum anticipated produced water production profiles for Flyndre and Cawdor development. CHEMICALS DISCHARGED WITH PRODUCED WATER Chemical use and discharge during production of well fluids are regulated under the Offshore Chemical Regulations 2002. Details (e.g. type/volume) of all proposed chemicals will be provided in a PON15D variation. As described in Section 2.10 the chemicals to be used during processing of the Flyndre and Cawdor hydrocarbons have yet to be decided on, however chemicals which are PLONOR or are of a lowest toxicity HQ will be prioritised . Proposed Control Measures The discharges of produced water are regulated by OPPC regulations and reported through EEMS. As such Maersk Oil are committed to the following mitigation measures; reporting total volumes of produced water discharged monthly reporting of the oil in water content of produced water bi‐annual sampling for chemical analysis. Ensure the installation meets
Flyndre and Cawdor Environmental Statement Section 5 Assessment of Potential Impacts and Control Measures 5.4. WIDER DEVELOPMENT CONCERNS The wider development concerns were identified as: accidental spills, potential for causing offences to European Protected Species and impacts to Protected Areas. 5.4.1. ACCIDENTAL SPILLS Uncontrolled hydrocarbon spills following an uncontrolled blowout at both the Flyndre and Cawdor wells are modelled and discussed in Section 6. This section also models the fate of the loss of the diesel inventory from the drilling rig, and discusses the tiered response strategy of Maersk Oil to combat and mitigate such spills. 5.4.2. PROTECTED AREAS AND SPECIES The closest protected area is the Dogger Bank pSAC which is situated 120 km to the south of the development. No significant impacts on any forms of marine or coastal protected areas have been identified. There are two forms of offences that can be caused to European Protected Species (EPS), the ‘injury offence’ and the ‘disturbance offence’, the control of potential offences to EPS is controlled by the issuing of licences, in the case of oil and gas activities this is by DECC. The EPS licence assessment for the activities associated with the Flyndre and Cawdor development are discussed below. INJURY EPS ASSESSMENT The loudest sounds generated from the Flyndre and Cawdor development will be during the installation of the 0.6 m diameter piles. If the activity was to proceed without any form of mitigation measures in place, there could be a very small risk of exposing cetaceans in the immediate vicinity of piling operations to sound levels that could cause a Temporary Threshold Shift, although the cetacean would have to be in such close proximity, 1m from the pile driver, this is considered unrealistic. A TTS is not a hearing injury, but a temporary reduced hearing sensitivity that is recoverable with time. Sound modelling illustrated that the received noise levels decrease very rapidly with increasing distance from the source, it is only in the immediate piling area, within the first few metres, that there is any risk of causing a temporary threshold shift in cetaceans. The modelling suggests the zone of injury was not exceeded. Providing the mitigation measures for piling are in place there will be a negligible risk of causing injury, and no requirement to apply for an EPS licence for the injury offence. DISTURBANCE EPS ASSESSMENT The modelling predicts that noise levels from piling may not fall below background levels out to a distance of 25 km. The piling sounds are likely to be audible (dependent upon prevailing ambient sound levels) to marine mammals out to this extent. It is possible that upon receiving these sound signals marine mammals could exhibit behavioural reactions and move away from the wider area of piling operations, as has been demonstrated from research studies into piling undertaken by the wind farm industry (Carstensen et al., 2006; Tougaard et al. 2009). In order to ascertain how many marine mammals could potentially be exposed to the sound levels, abundance and density estimates were calculated for the area affected using the SCANS‐II survey information, (this is currently the best available abundance and density estimates for the species likely to be present in the development area). A conservative estimate of the number of marine mammals that could be exposed to levels of sound above ambient levels within an area of 25 km 2 (derived from π * radius 2 ) i.e. area around each manifold is shown in (Table 5‐13). D/4114/2011 5 ‐ 21
Page 1 and 2:
Environmental Statement Flyndre and
Page 3 and 4:
Flyndre and Cawdor Environmental St
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Figure 1‐2 Flyndre and Cawdor Dev
Page 17 and 18:
Page 19 and 20:
1.5. ENVIRONMENTAL MANAGEMENT Flynd
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58: Flyndre and Cawdor Environmental St
Page 107: Flyndre and Cawdor Environmental St
Page 133 and 134: Inspections Reviews Investigation
Page 135 and 136: Ensure the installation meets
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Flyndre and Cawdor Development Envi
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
show all

Environmental statement - Flyndre and Cawdor - Maersk Oil

Create successful ePaper yourself

Delete template?

Save as template?