ExxonMobil said it has completed the world’s longest extended-reach well drilled from an existing offshore fixed platform drilling rig, increasing production rates at the Santa Ynez unit, offshore southern California, USA.

The well, from the Heritage platform in federal waters west of Santa Barbara, reaches 7,000ft below sea level and extends 6.3 miles horizontally.

Output from the Santa Ynez well will be equivalent to 5.8 million barrels of oil, which the company believes will be enough to meet the annual energy consumption of approximately 144,000 residents.

Exxon Mobil said in February the well had been drilled to over 37,000ft.

The Santa Ynez Unit, consisting of three platforms, has produced more than 450 million barrels of oil since 1981.