The Italian oil giant has started making final preparations for its $7.8 billion Goliat development in the Norwegian Arctic.

Goliat is set to become the world's northern-most offshore oil field, and will eventually pump 100,000 barrels of oil per day from reservoirs believed to hold around 175 million barrels of oil and eight billion cubic metres of gas.

Eni told The Guardian last week that the project's 64,000 tonne floating platform is in place and its production wells have been drilled, so the field is ready for production, although the company is still waiting for final approval from Norway's Petroleum Safety Authority.

The PSA said last week there was still some work left to do before Goliat can be allowed to proceed.

Starting up production at Goliat represents an important milestone for the oil patch, which is pushing into ever harsher conditions, and trying to overcome a raft of technical issues.

Completion at Goliat is more than two years behind schedule and reportedly around $1.5 billion over budget.

The Goliat platform was constructed in Korea, and was transported to the Barents Sea, 80km north off Norway earlier this year.

Eni says the Barents Sea is "the manageable Arctic" since it remains largely ice-free compared to other regions of the Arctic.

Eni's giant floating oil platform has been made to operate in hostile Arctic conditions and has been built to withstand once-in-100-year Barents Sea storm conditions and ice.

The project is understood to require an oil price of around $US95 per barrel to break even, meaning at the moment it is an expensive white elephant.

Eni (65%) and Statoil (35%) started exploring in the Barents Sea, north of Russia and Norway, in 1997 and made the discovery in 2000.

Goliat has two separate main reservoirs - the Kobbe and Realgrunnen - and contains oil with an overlying gas cap.

The Realgrunnen reservoir is situated 1000m below sea level and the Kobbe reservoir 1800m below sea level. There are also minor oil discoveries in the Snadd and Klappmyss formations.

The reservoirs are characterised by low pressures - 123bar from Realgrunnen and 192bar for Kobbe, presenting potential challenges for production flow.

Gas from the field will be injected into the Kobbe reservoir or transported to Melkoya.

It is expected that the maximum volume of gas production and reinjection will be 1.3Bcm and will occur a year after production commences.

The field is expected to be in production for up to 15 years, but field life may extend with new discoveries.

This facility will be partially supplied with power generated on land, which will reduce the need for local power generation.

The subsea development requires 22 wells from eight templates.

Pressure maintenance by means of water injection has been chosen in order to achieve effective reservoir drainage.

This will also provide an opportunity for the reinjection of produced water. Until a solution has been found for withdrawing the gas, the associated gas will be reinjected into the reservoir.

Statoil's last guidance was that the field was expected to start production before the end of September.