11.1 Introduction
The HALFDAN project refers to the platforms Halfdan A, B and C. An environmental and social impact assessment (EISA-16) is undertaken for the remaining lifetime of the ongoing Maersk Oil projects, and the entire life time from exploration to decommissioning for planned projects. The ESIA-16 shall replace the EIA conducted in 2010 “Environmental impact assessment from additional oil and gas activities in the North Sea, July 2011” which is valid for the period 1st January 2010 to 31st December 2015.
Notifications for the HALFDAN project were forwarded to the relevant authorities in accordance with article 3.1 of the Espoo convention.
In this section, a summary of the HALFDAN project and its likely significant transboundary impacts is provided. The section is focused on providing sufficient information to facilitate the identification of possible transboundary impacts. The rationale and support for the attributed level of significance and spatial extent can be found in detail in the relevant sections of the ESIS (section 6 and 7).
11.2 ESPOO convention
The ESPOO convention states that the concerned parties likely to be affected by transboundary adverse significant impacts are informed of and provided with possibilities for making comments or objections on the proposed activity.
The HALFDAN project can be found as item 15 (offshore hydrocarbon production) on the list of activities in appendix I to the convention, that are likely to cause a significant adverse
transboundary impact.
11.3 The HALFDAN project
11.3.1 Existing production and processing facilities
The HALFDAN project, includes the platforms Halfdan A, B, and C. Production was initiated at 1999. Maersk Oil has the license to explore for and produce oil and gas was extended until 8 July 2042.
Halfdan A comprises a combined wellhead and processing platform (HDA), one accommodation platform (HDB) and a gas flare stack (HDC).
Halfdan B comprises a processing platform (HBD), a wellhead platform (HBA), a riser platform (HBB) and an accommodation platform (HBC).
Halfdan C comprises an unmanned wellhead platform (HCA).
The processing facilities include hydrocarbon processing equipment (oil stabilisation, gas processing and processing of production water), auxiliary safety systems such as an emergency shutdown system, emergency blow-down system, fire and gas detection system, firewater system, etc.
Figure 11-1 Maersk Oil North Sea projects TYRA, HARALD, DAN, GORM and HALFDAN.
11.3.2 Planned development activities
The following main activities are planned to continue and optimise the production for the HALFDAN project and potentially access new hydrocarbon resources:
Seismic investigations provide information to interpret the geological structure of the subsurface and to identify the location and volume of remaining and potential new
hydrocarbon reserves. Seismic data is also acquired as part of drilling hazard site surveys to map and identify potential hazards to the installation of drilling rigs and to the drilling operation. Seismic data are also acquired as part of seabed and shallow geophysical surveys to map seabed and shallow soil conditions for the design and installation of pipelines, platforms and other structures.
Drilling of up to 4 wells at in existings free well slots and up to 20 new wells may be done under the HALFDAN project. Slot recovery or redrilling from existing wells of up to 6 wells at the existing structures can also be expected as part of the HALFDAN project. Drilling is performed from a drilling rig, which is placed on the seabed. Different types of drilling mud will be used based on the well and reservoir properties. Water-based mud and cuttings will be discharged to the sea, whereas oil-based mud and cuttings will be brought onshore to be dried and incinerated.
Well stimulation will be performed to facilitate hydrocarbon extraction (for a production well) or water injection (for an injection well).
Decommissioning will be done in accordance with technical capabilities, industry experience, relevant international conventions and under the legal frameworks at the time of
decommissioning.
11.3.3 Accidental events
As part of the production, accidental spills of oil, gas or chemical may occur. There is a risk of accidents that could lead to a major significant environmental and social impacts, such as vessels collisions or a well blow out. The risk of a well blowout is very unlikely.
11.3.4 Alternatives Project alternative
The 0 alternative (zero alternative) is a projection of the anticipated future development without project realization, and describes the potential result if nothing is done. For the HALFDAN project, this would mean that the production would cease. If no production is undertaken by Maersk Oil for the HALFDAN project in the North Sea, there will be no contribution from the HALFDAN project to the Danish economy or security of hydrocarbon supply and employment.
Tehcnical alternatives
Best environmental practice for the different type of activities planned for the HALFDAN project (seismic, pipelines and structures, production, drilling, well stimulation, transport and
decommissioning) is continuously monitored and applied when feasible.
Alternative location
The HALFDAN project is a continuation of production and activities at existing facilities. As such, there is no alternative location for the project.
11.4 Identified impacts – planned activities
Potential impacts to environmental and social receptors during planned activities at the HALFDAN project have been assessed in section 6. A summary of the potential worst case impacts is presented in Table 11-1.
Table 11-1 Summary of potential impacts on environmental and social receptors from planned activities at the HALFDAN project. The impact with the largest overall significance is provided for each receptor (without mitigating measures).
Receptor Worst case potential impact
Extent Overall significance of impact Climate and air quality Transboundary Moderate negative
Hydrography Local Minor negative
Water quality Local Minor negative
Sediment type and quality Local Minor negative
Plankton Local Minor negative
Benthic communities Local Minor negative
Fish Local Minor negative
Marine mammals Local or regional Moderate negative
Seabirds Local Minor negative
Cultural heritage None None
Protected areas (UNESCO, nature reserve) None None
Natura 2000 No significant environmental effects
Marine spatial use Local Negligible negative
Fishery Local Negligible negative
Tourism None None
Employment and tax revenue Local or national Positive Oil and gas dependency Local or national Positive
Transboundary adverse impacts have been identified for climate and air quality, where the emissions from the HALFDAN project may contribute to climate change and air pollution. Maersk Oil has implemented a structured energy efficiency process and conduct comprehensive reviews to identify ways to improve energy efficiency offshore. The production has become more energy efficient over the years, and in 2013 the environmental management system at Maersk Oil was ISO-14001 certified.
No other significant adverse transboundary impacts have been identified for the planned activities at the HALFDAN project.
A Natura 2000 screening is presented for the planned activities. It is assessed that the planned activities will have no significant environmental effects on the conservation objectives of the habitat types or species in the national and international Natura 2000 sites (section 10).
11.5 Identified impacts – accidental events
Potential impacts to environmental and social receptors during accidental events from the HALFDAN project have been assessed in section 7. A summary of the worst case potential impacts (without mitigating measures) is presented in Table 11-2.
Table 11-2 Summary of potential impacts on environmental and social receptors for accidental events at the HALFDAN project. The impact with the largest overall significance is provided for each receptor (without mitigating measures).
Receptor Worst case potential impact
Extent Overall significance of impact Climate and air quality Transboundary Moderate negative
Water quality Transboundary Moderate negative
Sediment type and quality Transboundary Moderate negative
Plankton Transboundary Minor negative
Benthic communities Transboundary Major negative
Fish Transboundary Major negative
Marine mammals Transboundary Major negative
Seabirds Transboundary Major negative
Cultural heritage National Moderate negative
Protected areas (UNESCO, nature reserve) Transboundary Major negative
Marine spatial use Transboundary Moderate negative
Fishery Transboundary Major negative
Tourism Transboundary Major negative
If a major oil spill occurs, there is a risk of major negative transboundary impacts. The risk of a major oil spill is very unlikely, but could potentially have significant, adverse transboundary impacts. Oil released could cross maritime boundaries with Norway, Germany, the Netherlands and the UK. The oil spill modelling identified the north and west of Denmark as most vulnerable to oil beaching, although Norwegian, German and Dutch shorelines could also be affected.
Maersk Oil follows industrial best practices for prevention of accidents based on identification of major hazards assessed through risk assessment. Emergency response and contingency planning have been developed to limit the consequences of a major accident related to its projects.