West Sole

Location and Geology

The West Sole gas field is located under the North Sea, approximately 44 miles (70 km) off the East Yorkshire coast. It is situated in the Sole Pit area of the southern North Sea. The gas reservoir is a Rotliegendes sandstone of Lower Permian age, located at a depth of 9,000 feet (2,740 m) with a thickness of 262–430 feet (80–131 m). The reservoir is capped by Zechstein salt.

Field Structure and Size

The West Sole structure runs north-west to south-east and is about 12 miles long and 3 miles wide (19 km by 4.8 km). It extends over Block 48/6 only.

Discovery and Production

The field was discovered in 1965, and production began in March 1967, marking the first British offshore natural gas delivered onshore for commercial use. The original determination of the gas in place amounted to 57 billion cubic meters.

Ownership and Operation

The field was originally licensed to BP Exploration UK Ltd. In 2012, ownership was transferred to Perenco UK Ltd, which currently operates the field.

Production and Export

Gas and associated condensate from the West Sole field are exported via two pipelines (16 inch and 24 inch diameter) to the Easington gas terminal in East Yorkshire. The field has produced more than 2.2 trillion cubic feet (Tcf) of gas since 1967.

Gas Composition and Properties

The gas composition at West Sole includes:

• Methane: 94.0%
• Ethane: 3.2%
• Propane: 0.6%
• Butane: 0.2%
• Pentane: 0.1%
• Hexane: 0.1%
• Heptane: Trace
• Nitrogen: 1.5%
• Carbon dioxide: 0.2%
• Gas gravity: 0.594%
• Mean condensate content: 2.0 bbl/million cu ft
• Calorific value: 1024 Btu/cu ft.

Offshore Installations

The field has been developed through several offshore installations, including:

• West Sole WA complex
• West Sole WAP platform
• West Sole WAS platform
• West Sole WB platform
• West Sole WC platform
• West Sole WE platform (removed in 1978)
• Hyde platform
• Newsham platform
• Hoton platform
• Babbage platform
• Seven Seas platform

These installations include steel jacket platforms and subsea production systems, some of which are part of the 'Villages' gas fields named after villages lost to the sea along the Holderness coast.

Production Profile

The peak production from the West Sole field was 2.28 billion cubic meters per year in 1972. By the end of 2014, the cumulative production was 57,619 million cubic meters. The field has recovered 94.69% of its total recoverable reserves, with production expected to continue until the field reaches its economic limit in 2033.

Recent Developments

Perenco UK has implemented various technologies to sustain production, including the use of velocity strings to increase fluid velocities in partially depleted reservoirs. This has resulted in production gains and extended the field's life. The field remains a significant production hub in the southern North Sea, with potential for future development and tie-in of nearby gas discoveries.

Future Prospects

The West Sole field continues to be an important part of the UK's offshore gas production. With ongoing recompletions and the application of new technologies, the field is expected to remain productive for decades to come. Additionally, Perenco is exploring carbon capture projects in the North Sea, which could further extend the field's utility and sustainability.