Oil tankers berthed at Sullom Voe Oil Terminal
Oil Tankers berthed at Sullom Voe Oil Terminal

Oil & Gas Marine Infrastructure in Scotland’s North Sea

The maintenance of Sullom Voe Oil Terminal’s marine infrastructure requires ongoing structural assessment

NIRAS has a local site office to provide year round technical assistance and contract management for critical maintenance and life extension works at the jetties.

NIRAS has been providing engineering support to Shetland Islands Council (SIC) for nearly 50 years. The firm was engaged by SIC for the development of a major new oil port at Sullom Voe which has one of the largest throughputs of any oil terminal in Europe. Sullom Voe Terminal oil export jetties, constructed by Christiani & Nielsen in the 1970s were originally designed by Peter Fraenkel & Partners (now part of the NIRAS Group).

Detailed design of four jetties

NIRAS was responsible for the detailed design and construction supervision of four jetties, three of which are for crude oil export in vessels of up to 350,000 dwt and the fourth for crude oil and LPG export in vessels of up to 120,000 dwt or 80,000 cu.m.

The jetty construction consists of tubular steel piles driven into rock, with tension piles anchored by means of steel joists drilled and grouted a further 15m below the pile toes. The superstructure of the jetties is reinforced concrete.

Additional Administration Building and a small boat harbour

The project included the construction of a Port Administration Building, covering 700m². In addition to administration offices, the building also houses the port control room, in which is installed the surveillance radar, the VHF radio system and the telemetry for the navigation lights in the port and approaches, all of which were designed by the firm. Also provided was a tug and small boat harbour for vessels of up to 10,000 dwt, comprising eleven 20 metre diameter straight web pile cells supporting a concrete deck on rock infill.

NIRAS was also responsible to the SIC for vetting many aspects of the onshore development, including tankage and ballast water handling and treatment. Subsequently, a hydrographic survey was carried out for a second entrance route to the port. Navigation lights and a remote radar system to cover this route were designed, constructed and commissioned in fifteen months.

Sullom Voe Oil Terminal is a vital north sea oil infrastructure asset, which relies heavily on the integrity of its marine structures.

Since the opening of the terminal, NIRAS has been responsible for the annual maintenance and life extension programme.

This is a rolling programme for maintenance of the jetties including:

  • Marine structures
  • Impressed current cathodic protection system
  • Paintwork of the jetties and dolphin structures
  • Concrete repairs and cathodic protection in concrete
  • Half Cell, Chloride sampling, Visual & hammer tests
  • Assessment and remedial work at Construction Jetty & RoRo
  • Assessment of steel access towers & Jib
  • Inspection on Tug Harbour
  • Fender replacements and mooring analysis
  • Hydrographic Surveys, Laser and Topo Surveys
  • Asset Management