Build drilling platforms in the extreme environment of the North Sea to pump natural gas
The West Sole gas field was discovered by UK oil and gas company British Petroleum (BP) in 1965. The field – around 70km off the coast of Yorkshire – was the first to be developed in the North Sea. West Sole produced its first gas in 1967.
The West Sole natural gas reserve is in an area about 19.3km long by 4.8km wide and lies 2,700m below the sea bed. When discovered, the field had estimated reserves of 61bn m3 of gas.
West Sole was owned and operated by BP until 2012 when the field was sold to oil and gas company Perenco UK.
BP had a total of 5 operating platforms in the West Sole field. They were the WA main platform, the WAP platform and the WAS platform. These 3 rigs were manned. The other 2 – the WB platform and the WC platform - were unmanned.
BP used 2 pipelines to transport gas from the field to a shore terminal at Easington in Yorkshire for processing.
The West Sole drilling platforms were originally tubular steel rigs supported above the waves by steel legs.
Since the rigs were designed in the 1960s, engineers have developed a better understanding of wave forces – as well as learning lessons from the loss of several platforms.
Early North Sea platform failures included the Sea Gem oil rig. The steel legged structure collapsed in 1965, killing 13 of its crew.
West Sole Gas Field
The West Sole Gas Field was discovered by UK oil and gas company British Petroleum (BP) in 1965. The field – around 70km off the coast of Yorkshire – was the first to be developed in the North Sea. West Sole produced its first gas in 1967.
Did you know …
Natural gas was first discovered in the West Sole field by the Sea Gem rig in 1965. The structure was the UK’s first offshore drilling platform. It also became the UK’s first oil rig disaster.
On 27 December 1965, as the Sea Gem was being prepared to move from a site about 42km east of Lincolnshire, 2 of its steel legs crumpled in stormy weather. The structure tilted sideways and sank.
A passing British ship rescued rig workers from the sea, but 13 crewmen died and another 5 were badly injured.
Difference the project has made
Although West Sole wasn’t the first natural gas discovery in the North Sea, it was the first real commercial find and encouraged further exploration of the region.
The field continues to produce natural gas, helping to power UK homes and industry.
Although production has fallen in recent years, the oil and gas industries have contributed around £190bn in UK tax revenues since the 1960s.
How the rigs are maintained
Maintenance and upkeep of the West Sole rigs was a constant challenge for engineers. As an example, an underwater inspection in 1972 uncovered damage to a brace on one of the platforms.
The pipeline carrying gas to the onshore processing plant ran close to the rig. This meant engineers had to strengthen the brace while protecting the pipe.
The project team sank new piles into the clay beneath the platform as part of the repairs. Workers used a jack-up barge to provide a stable platform for sinking the piles.
A jack-up barge is a mobile platform. It’s made up of a floating hull fitted with movable legs. These can raise the hull above the surface of the sea. Once on location, the legs are lowered to the sea bed and the hull unit is jacked up into place.
Using the jack-up barge as a platform for sinking the piles helped reduce vibrations that might affect both the rig and the pipeline.
Engineers also protected the pipeline with steel covers during the work.