The oil major said the deepwater project - the first to expand an existing GoM oil and gas field with "significant" new infrastructure - should extend the greater Mars Basin life to 2050 or beyond.

Combined future output from Olympus - Shell's seventh GoM-based drilling and production platform - and the Mars platform is expected to reach an estimated 1 billion barrels of oil equivalent.

"With two large platforms now producing from the deepwater Mars field, this project demonstrates our deepwater project delivery and leadership," Shell Upstream Americas deepwater executive vice president John Hollowell said.

"We safely completed construction and installation of the Olympus platform more than six months ahead of schedule, allowing us to begin production early from the development's first well.

"Olympus is the latest, successful start-up of our strong portfolio of deepwater projects, which we expect to generate substantial value in the coming years.

"Deep water will continue to be a core growth opportunity for Shell."

The Mars B development (Shell 71.5%, BP 28.5%) also includes export pipelines, a shallow-water platform near the Louisiana coast and subsea wells at the West Boreas and South Deimos fields.

Olympus, which is sitting in about 945m of water, is expected to lift production from an average of 60,000 barrels of oil equivalent per day in 2013 to 100,000boe in 2015 through additional development drilling.

Shell said its wholly owned Cardamom project in the GoM, targeting 50,000boepd, was on track to a 2014 production date, while work was underway on the 50,000boepd deepwater Stones development, which successfully reached a final investment decision in May.

Shell has released an Olympus-themed video here: