LENSKYY V. F., RUDENKO V. V., BLAGOVYDOV L.B., KADZHOYAN Y. S., KRAVCHISHIN D. N., TASALIEV D. I.
OJSC “CDB “Corall”, Ukraine, 2LUKOIL-Kaliningradmorneft Ltd., Russia

In 2008 Fixed Offshore Ice-Resistant Offloading Terminal (referred to as FOIROT) was put in commission.

FOIROT is part of Varandey Oil-Loading Terminal (VOLT) and is intended for contact-free mooring and loading of 20,000...70,000 ton tankers with stock-tank oil piped from VOLT onshore facility.

FOIROT is located within Russian Federation territorial waters, 12 miles offshore Varandey town, at water depth of about 18 meters.
An idea to build an offshore fixed terminal as part of VOLT had been studied by LUKOIL for several years and, in 2005, particular steps were taken to implement the project, namely, LUKOIL-Kaliningradmorneft (general contractor) was assigned as the FOIROT Constructor and CDB Corall (Sevastopol) as the FOIROT Designer.

Client, Joint-Stock Company Varandey Terminal, issued a performance specification for FOIROT design and construction, which included both documentation developed earlier by KBR with participation of Krylov Research Institute and some new conditions and requirements.

Major alterations of KBR-proposed design can be broken down into three groups:

1. Alterations that would suit new location and Client's new requirements (changes in base structure design, piling foundation, oil offloading process, extension of offloading arm and hose, etc.)

2. Alterations ensuring feasibility of FOIROT construction at LUKIOL-Kaliningradmorneft steelwork plant (ZPSMK), and feasibility of its transportation to site and offshore installation.

3. Design enhancements, such as use of a roller support instead of the ball race, modification of the offloading arm design, ice protection of sub-sea pipeline.

After taking all the changes into account, the development of virtually new design began in the middle of 2005. On the grounds of the Register-approved basic design, development of detail drawings began in December 2005.

Development of FOIROT design solutions involved the use of results from extensive and long-term metocean and soil studies for the FOIROT operation area that were performed by Arctic Marine Engineering Geological Expeditions company (AMIGE), Informar Company, Arctic and Antarctic Research Institute (AARI).

The oil is piped to FOIROT through two pipeline runs of 800 mm diameter each. FOIROT process equipment and piping provide maximum oil offloading capacity of 8000 m³/h. FOIROT annual capacity is 12 million tonnes of oil.

FOIROT is designed for operation in severe climate of Pechora Sea under 100-year load conditions:
? Wind velocity, m/s - 36
? Wave height h0.1%, m - 8.3
? Current velocity (combined with maximum wave), m/s - 0.75
? Rafted ice thickness, m - 2.7

The terminal is a steel caisson structure consisting of a base structure piled to the sea bottom, living quarters, and rotary upper structure called Mooring and Loading Arrangement or MLA.

Shape and dimensions of the base structure have been selected based on the following considerations:
? to provide most favorable conditions for tanker during loading, which is to create an ice-hole at leeward side during ice season. For that, FOIROT breadth at boot-topping was made equal to the hull breadth of a 70,000-ton tanker thus shielding tanker hull from direct ice impact,
? to select such angle of inclination of tapered section generatrixes that assures rough equality of design wave and ice loads. This equality of loads ensures optimum weight and overall dimensions of the structure.

Base structure with living quarters weights approximately 10,000 tonnes. The weight of the base structure was monitored especially closely during the development. Thorough evaluation and detailed calculations were carried out for virtually every and each structure member and developed design solutions allowed the base structure weight to be reduced to the lowest possible level.

FOIROT is equipped with a complete range of facilities supporting life activity of the personnel and their safe stay on the platform over a long period of time. FOIROT crew consists of 8 people each staying in a single-person cabin. Additionally, 4 more people can stay in two-person cabins.

A number of research activities was performed during the design development by some leading companies, such as:
• Model testing of the base structure in the ice and nautical pools of the Krylov Research Institute to determine ice and wave loads;
• Calculations of the FOIROT base structure stability on the sea bottom during construction and mounting period (before pile driving), and calculations of piling for operation within 25-30 years were carried out by Gekon, Ltd;
• Calculations of spray and weather icing, and development of anti-acing counteractions were carried out by Arctic and Antarctic Research Institute;
• Calculations of “FOIROT-tanker-towboat” system behavior were carried out by Saint-Petersburg State Polytechnic University;
• Model testing of the “FOIROT-tanker” system was carried out in the ice pool of Helsinki Technologic University;
• Model testing of the “FOIROT-tanker” system was carried out in the nautical pool of Krylov Research Institute.

Creation of FOIROT took ~25 months from the receipt of the Client’s design basis until its installation offshore on the site; this also included development of basic design, approval of the design, development of detailed drawings, purchase of equipment and materials and the construction at ZPSMK steelwork plant in Kaliningrad. The FOIROT construction itself was completed in 15 months, and its transportation from Kaliningrad to the Pechora sea shelf, offshore installation, including piling of the base structure and mounting of the rotating structure took about 2 months.
The deadline for construction of FOIROT was extremely tight, but nevertheless it was met thanks to combined efforts of the general contractor – LUKOIL-Kalingradmorneft, Ltd., the general designer – CDB Corall, and numerous subcontractors as well as vendors of equipment and materials.

Oil and gas of Arctic shelf 2008