Records set as Lun-A steps on the gas
  from: Asian Oil & Gas
  by: Terry Knott
  Friday, October 27, 2006

The 21,800t floatover topsides deck for the Lunskoye-A gas production platform was successfully installed in the Sea of Okhotsk, 15km northeast of Sakhalin Island on 23 June, setting a new record as the industry's heaviest floatover deck installation.

Following an 11-day tow from Samsung Heavy Industries' shipyard on Geoje Island in South Korea, the massive structure was mated onto the four legs of the platform's concrete gravity base structure (CGBS), placed on the seabed last summer in 48m of water. Lunskoye-A will become Russia's first offshore gas platform, operated by SEIC, a consortium led by Shell.

Transportation and installation of the Lun-A topsides were carried out by Saipem on a purpose-built barge. Leg mating units, weighing 130t each, were pre-installed in each of the CGBS legs to centralise the topsides during the lowering process and to act as shock absorbers during the initial contact. The installation process took over nine hours, involving coordination with Saipem's Castoro-8 installation support vessel and a fleet of five tugs and anchor handling vessels.

Prior to the offshore operation, the Lun- A deck was raised onshore to a height of over 24m to allow the loadout support frame to be slid underneath, believed to be a world record for a land lift. A purpose built 190m long, 95m wide T-shape barge was then used to transport the topsides over a distance of 2831km, towed by three tugs, to the field.

Lun-A also has special sliding connections - referred to as friction pendulum bearings - installed between the CGBS structure and the deck, which allow the topsides to move independently of the base, providing protection against damage during a severe earthquake. This is the first time these bearings have been used in the offshore industry.

The CGBS for Lun-A was the first of its kind to be built in the port of Vostochnoye in the Primorsky Krai, Russian Far East. The CGBS consists of a base caisson and four shafts topped by cylindrical steel deck connector legs that support the topsides. The structure has a total dry weight of 103,000t; the base section measures 105m by 88m and 13.5m high; four 56m-high shafts sit on top of the base, with diameters over 20m.

Following hook up and commissioning, drilling of gas production wells will begin from the platform, which will be the main source of gas for Russia's first LNG plant at Prigorodnoye, under construction in the south of Sakhalin Island. LNG production is expected to start in 2008.

The Lun-A platform includes 27 well slots for directional drilling which will enable full development of the field, and has a production capacity over 50 million m³/d of gas and approximately 50,000b/d of condensate. Separation and treatment of the Lunskoye gas and condensate will be undertaken onshore at a new onshore processing facility, which will also supply power to the platform via submarine cable. AOG

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