Drilling works in a new well at Centrica’s York gas field have started.
It will tap into an additional 20 billion cubic feet of gas – enough to heat half a million UK homes for a year.
The energy giant invested £80 million to extract gas from the field which is expected to continue providing gas to the country until 2020.
A new gas compressor will be installed early next year, boosting the amount of gas which can be produced from York by another 10 billion cubic feet, Centrica said.
It will also create new jobs.
The gas extracted is piped ashore at Easington terminal, where it is processed and sent to the National Grid by Centrica Storage.
Drilling is expected to be completed early next year.
Jonathan Lilley, Wells Director for Centrica Energy in the UK and the Netherlands said: “Drilling a fourth well at York is a great example of how we’re getting more gas out of the North Sea.”