Devenick

Devenick Gas Field Profile

Location

The Devenick gas field is located in the UK Central North Sea, approximately 145 miles (233.3 km) north-east of Aberdeen, Scotland. The field spans across several blocks, including UKCS Blocks 9/24b, 9/24c, and 9/29a.

Water Depth

The field is situated in water depths varying between approximately 115 meters and 130 meters.

Field Characteristics

• The Devenick field is a high pressure, high temperature (HP-HT) gas condensate discovery.
• It was developed to produce gas, with the field's production dependent on the East Brae platform for control and export.

Facilities and Infrastructure

• Wells: The field was developed by two wells, S1 and S2, connected to a subsea manifold. The S1 well was originally drilled as an appraisal well but was later recompleted as a development production well. The S2 well was plugged and abandoned in 2015 due to high levels of hydrogen sulfide (H2S) in the reservoir fluids and was never commissioned.
  • The 9/29a-2Z (S2) well was plugged and abandoned in 2015, and its Xmas tree, integrated protection structure, and wellhead were recovered to shore for recycling in 2017.
• Manifold: A subsea manifold connects the wells to the production flowlines.
• Flowlines and Umbilicals: Production flowlines and umbilicals connect the S1 and S2 well locations to the manifold. These are trenched and backfilled over most of their length with spot rock placement where required. Surface-laid cooling spools and associated rock-covered protection structures are also part of the infrastructure.
• Pipelines: The production pipeline, methanol pipeline, and umbilical connect the Devenick manifold to the East Brae platform. These pipelines run via Blocks 9/28c and 16/03e and are also trenched and backfilled.
• SSIV Structure: A Subsea Isolation Valve (SSIV) structure is located at the East Brae platform end of the production flowline, along with an SSIV control umbilical.

Production History

• The Devenick field started production in 2012 from the S1 well. Due to the dependency on the East Brae platform, production at Devenick cannot continue after the cessation of production at East Brae.

Decommissioning

• Decommissioning of the Devenick facilities is planned as part of the wider Brae Area overall decommissioning project. TAQA Bratani Limited (TAQA) is the operator responsible for this process and is seeking approval from the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED).
• The proposed date for the permanent cessation of Devenick production is 2024, although this is subject to the performance of the installation, reservoir, and market conditions.

Technological Innovations

• The Devenick project was notable for the first implementation of a fully reelable bulkhead using pipe-in-pipe (PiP) technology in 2011. This technology enhanced pipelay schedule efficiency and allowed for tight separation of PiP in independent sections.

Environmental and Regulatory Considerations

• The decommissioning process includes a full field seabed clearance verification survey to ensure compliance with environmental regulations. The project is subject to approval under the Petroleum Act 1998, as amended.
• The environmental impact assessment for the decommissioning operations has been conducted, considering the well-developed area for oil and gas extraction and ensuring minimal environmental disruption.

In summary, the Devenick gas field is a significant HP-HT gas condensate field in the UK Central North Sea, developed with advanced subsea infrastructure and now undergoing decommissioning as part of a broader regional project.