British energy company EnQuest said Monday it delivered its first batch of oil from a North Sea field that could hold more than 10 million barrels of oil.

EnQuest announced delivery from the Scolty/Crathes complex about 100 miles north of Aberdeen, Scotland, came ahead of schedule and under budget.

"Unit operating costs are expected to be under $15 per barrel in the initial peak volume years and production is anticipated to continue until 2025," EnQuest CEO Amjad Bseisu said in a statement.

The company estimates the complex holds up to 15 million barrels of gross oil technical reserves.

EnQuest this year cut its full-year spending plans to the low-end of its estimate of between $700 million and $750 million, but kept production guidance in place at around 46,000 barrels of oil equivalent per day.

In a separate statement, the company said Monday it finished with a restructuring effort launched in October. Restructuring gives the company a better capital structure and helps reduce some of its debt obligations.

First oil for EnQuest comes amid doubts about the trajectory for North Sea producers. Industry group Oil & Gas U.K. said the regional industry has been resilient in the era of lower crude oil prices. Costs have declined by up to 50 percent, while output since 2014 has increased 10 percent. Nevertheless, the industry has seen steep losses in revenue and more than 100,000 jobs have been lost since 2014.

Companies have started to grow accustomed to a market where crude oil is trading in the upper $40-per-barrel range, but the British decision in June to leave the European Union is something of a distraction for an economic sector that depends in part on external markets for success.

EnQuest splits its interest in the Scolty/Crathes complex with Hungarian energy company MOL.