Wenlock

Location

The Wenlock gas field is located in the Southern Basin of the UK Continental Shelf (UKCS), specifically in licence blocks 49/12A. It is situated approximately 98 kilometers offshore northeast of the Bacton Gas Terminal, 6.5 kilometers north of the Viking A field, and 36 kilometers northwest of the Indefatigable field.

Discovery and Development

The Wenlock gas field was discovered in 1974. Alpha Petroleum Resources Limited acquired equity in the licence from BP in 2001 and from ConocoPhillips in 2005. The field was developed with the installation of a three-slot Normally Unmanned Installation (NUI) platform in September 2006. The first well was drilled and started production in December 2007, followed by two subsequent wells drilled and started production in 2008 and 2009.

Production

Gas production from the Wenlock field began in December 2007. The gas is exported via a 37-kilometer pipeline to the Perenco-operated Indefatigable platform and then further to the Bacton Gas Terminal. By the end of 2016, the Wenlock field had produced 41 billion cubic feet (bcf) of gas, with estimated remaining reserves of 4.5 bcf.

Infrastructure

The Wenlock NUI platform is linked to the Perenco-operated Inde AC platform via two pipelines: an 8-inch (PL2355) and a 3-inch (PL2356) pipeline. These pipelines are both 36.231 kilometers long, made of API 5L X65 carbon steel, and are trenched and buried 1.0-1.5 meters below the seabed level. Chemicals for hydrate and corrosion inhibition are supplied from the Inde AC platform via a dedicated 3-inch pipeline piggy-backed to the gas export line.

Decommissioning

Due to declining production, the Wenlock field has become uneconomic, and a Cessation of Production (CoP) application was approved by the Oil and Gas Authority (OGA) in 2021. Decommissioning activities are underway, including the plugging and abandonment of the wells. There is also a consideration to repurpose the platform as an artificial nesting site for bird species, particularly to offset the impact of offshore wind developments in the area.

Future Plans

The platform may be retained and adapted to serve as a nesting site for seabirds, such as black-legged kittiwakes, which have been observed nesting on various North Sea platforms. This repurposing would involve maximizing the use of existing structural elements while minimizing disturbance to the seabirds already present at the site.

In summary, the Wenlock gas field is a mature gas production project that has been in operation since 2007, with significant production history and ongoing decommissioning activities, along with potential future use as a bird nesting site.