Albuskjell 1/6 A

person Norwegian Petroleum Museum
Installed in 70 metres of water during 1976, Albuskjell 1/6 A came on stream in 1979.
Brief facts:
  • Installed in 1976
  • On stream 26 May 1979
  • Production ceased 26 August 1998
  • Removed 2007-13
  • Also known as Albuskjell Alpha
— Albuskjell 1/6 A. Photo: Husmo Foto/Norwegian Petroleum Museum
© Norsk Oljemuseum

The Albuskjell oil and gas/condensate field lay 21 kilometres north-west of the Ekofisk Complex and extended across blocks 1/6 and 2/4, licensed to Norske Shell and the Phillips group respectively. It was later unitised on a 50-50 basis.

Shell drilled discovery well 1/6-1X in 1972, in cooperation with Phillips, close to the boundary with block 2/4. The Albuskjell structure formed rather differently from other fields in the Greater Ekofisk area. Deposited 22-55 million years ago over a salt dome, its producing layer comprises carbonate rocks with some thin strips of shale.

Albuskjell 1/6 A produced from 11 wells and was tied back by gas and oil pipelines via Albuskjell 2/4 F to Ekofisk 2/4 R. A separate flare stack was linked to the platform by a bridge.

Processing comprised an oil/gas separator. Gas was dehydrated and compressed before export in a 24-inch pipeline. The separated oil was exported through an 18-inch line. Before being piped away, the oil and gas passed through a fiscal metering station to measure the volumes produced.

The platform was designed in a collaboration between Cork Shipyard, Oil Industry Services (OIS), Nylands Verksted, Tangen Verft, Aker Stord and Thyssen. Morco AS was the drilling contractor.

Like that on Albuskjell 2/4 F, the jacket (support structure) for 1/6 A was unusual because its two topmost frames were filled with water to prevent them heating up in the event of a fire. It was built at Aker Verdal, with the module support frame (MSF) fabricated by Aker Stord.

The living accommodation provided 46 beds, later 96.
The water depth was 70 metres.
Total weight of platform and pipelines was 25 300 tonnes.
The tip of the flare stack was 94 metres above sea level.
The derrick was 74 metres tall.

It was originally designed as a combined production, drilling and accommodation platform, but the derrick and drilling equipment were removed as early as 1979. The accommodation module with helideck was replaced in 1983 to increase beds from 46 to 96. The actual lifting operation was performed by the Balder crane barge from Heerema/Seaway.

When the Albuskjell field was shut in during July 1998, it had produced
46 million barrels or 7.353865 million standard cubic metres (scm) of oil
15.53439 billion scm of gas
990 139 tonnes of natural gas liquids (NGL)

Wellheads

Once a well has been fully drilled, it is completed for either production or injection. The purpose of well completion is to isolate the oil/gas production flow (wellstream) so that the whole path from reservoir to platform topside is leak-free.

This is achieved by running production tubing inside the casing (well liner) installed during drilling. These tubes are attached to the wellhead on the platform, which seals the top of the casing and provides a system for controlling pressure in the well.

Reservoir pressure causes crude oil/gas to flow up through the production tubing to the wellhead, which contains master and choke valves. These make it possible to shut down a producer or to adjust the desired volume of flow from each producer.

The Xmas tree (so called because of its shape) is installed on the wellhead. It contains control and work valves, such as the one for injecting diesel oil and various chemicals into the production tubing. Wellhead and Xmas tree form part of well control system.

The automatic master valve sits in the vertical section of the wellhead and is kept open by hydraulic pressure. Supported by the manual master valve, it represents the first barrier for shutting down the well.

Designed to cope with a substantial pressure drop, the choke valve is used to regulate wellstream flow and pressure from the individual well. This ensures that pressures in and production rates from all the wells are virtually identical.

The wellstream flowing through the choke valve is conducted to the production or the test manifold through a block valve before entering the separator on the platform.

Separation

The wellheads delivered a mix of crude oil, natural gas and water through either the production or the test manifold to the separators. This mix had to be split into its various components for further processing on the platform.

Albuskjell 1/6 A
Production separator in module P07. Photo: Jan A. Tjemsland/Norwegian Petroleum Museum

Measuring 20 metres long, the production separator was a horizontal tank with a diameter of four metres. It worked on the principle that the heaviest components in the tank would sink to the bottom while the lighter liquids and gas remained higher up.

This was a three-phase device with a lower phase of water, a middle one of crude oil and an upper gas phase. It was equipped internally with inlet deflectors, seven perforated guide plates and a demister for the gas outlet.

The test separator worked on the same principle, but was rather smaller. Its applications included testing the production rate from a single well so that the choke in the wellhead could be correctly adjusted.

Gas compression

Compression was needed to increase the gas pressure before it entered the pipeline which ran to Ekofisk 2/4 R. The train comprised a gas cooler, suction scrubber and gas compressor.

   Gas cooler. This reduced the temperature of gas emerging from the separator in order to prevent the compressor from running too hot. The gas circulated around a set of water-cooled tubes, lowering its temperature to 27°C.

   Suction scrubber. Once the gas was cooled, some liquids had to be removed in this device. It comprised a vertical tank four metres tall and two metres in diameter.

   Gas compressor. Driven by a gas turbine, this unit increased the pressure from 465 pounds per square inch gauge (psig) to 1 305psig while also raising the gas temperature from 27°C to 100°C.

Gas dehydration

albuskjell 1/6 a,
Drying unit - also called Glycol Contactor. Photo: Jan A. Tjemsland/Norwegian Petroleum Museum

Gas piped to Ekofisk 2/4 R had to be completely free of water to avoid ice or hydrate (hydrocarbon ice) plugs forming in the pipeline during transport through the cold seawater.

The gas was first cooled from 100°C to 27°C in two stages before being mixed with triethlyene glycol – a liquid which attracts water. After it had been dehydrated in this way, the gas was reheated to 65°C in a heat exchanger.

In all, the dehydration system comprised the gas/gas heat exchanger, the gas aftercooler and the glycol contactor.

   Gas/gas heat exchanger. This had two functions – cooling down the incoming gas from 100°C to 60°C and heating up the outgoing gas from 27°C to 65°C. Two gas streams passed each other in the unit.

   Gas aftercooler. This contained a number of water-cooled tubes which the gas circulated around to reduce the temperature from 60°C to 27°C.

   Glycol contactor. This unit comprised a vertical tank 13 metres tall by two metres in diameter. The gas bubbled up through a number of vessel filled with glycol and ended up dehydrated at the top. Water-saturated glycol was circulated out and replaced by more dry chemical.

Fiscal metering

Oil and gas processed on the platform and exported to the Ekofisk Complex was metered in a metering station on 1/6 A. Data from these instruments were transmitted to a Daniel computer for processing before being transferred to the Ekofisk Complex via a telemetric link.

Corresponding meters were also provided for gas consumed on the platform and for the flare boom.

 Gas metering. The gas meter comprised a tube containing pressure and temperature gauges, a densimeter and a flow orifice. When the gas passed through the orifice, its speed rose and its pressure fell. Knowing the density and composition of the gas meant the pressure drop could be used to measure the quantity exactly.

albuskjell 1/6 a
Meter Prover (this one at Edda 2/7 C). Photo: Kjetil Alsvik/Norwegian Petroleum Museum

Oil metering. A turbine flow meter was used to meter oil. Small magnets located on the outer edge of the rotor transmitted signals to sensors in the rotor housing. The latter could then measure the speed at which the rotor turned, and thereby arrive at the exact amount of liquid flowing through the meter.

Calibration. Such turbine flow meters had to be calibrated regularly to ensure accurate measurements. Known as a meter prover, this system comprised a horseshoe-shaped test loop which contained a rubber ball.

During calibration, oil was conducted through the loop and pushed the ball ahead of it. Measuring how long the ball took to complete the circuit, given that the loop’s exact volume was known, made it possible to measure oil flow accurately. These data were then compared with the pulses from the turbine flow meter.

Albuskjell 1/6 A
Tor Hindrumsen checks the control panel in the control room at Albuskjell 1/6 A. Photo: Jan A. Tjemsland/Norwegian Oil Museum

Control room

The control room was the platform’s heart, monitoring and controlling all important processes on board.

Utilities

Glycol regeneration Glycol coming from the gas dehydration facility had a pressure of 1 205psig and was saturated with water and gas. After its pressure had been reduced, the gas was removed in a degassing pot.

The glycol was then filtered and heated in the regenerator to evaporate the water, and passed through pumps to reach the same pressure as the dehydration unit before being returned to it.

Gas pipeline pigging. To remove slag and water from the gas pipeline, a sphere was launched into it at 1/6 A and followed the gas flow to Ekofisk 2/4 R where removal took place.

Oil pipeline pigging. The pig in the oil pipeline had a different shape to the unit used for the gas pipeline, but otherwise functioned in the same way.

Power supply

Electricity for the platform came from the generator room, where four generating sets were driven by Kongsberg gas turbines. Two of these turbines were later removed and replaced by a diesel engine. Electric switchboards were installed in the module above the generators. The working voltage was 480V.

Other utilities

Other utilities on the platform included fire extinguishing and rescue systems, instrument air, chemical injection and drinking water.

Also provided were diesel and lube oils, gas lift equipment, a workshop, helideck, accommodation module, flare boom, radio communications and so forth.

Production ceased in 1998, and the platform became unmanned in 1999 with remote monitoring from Ekofisk 2/4 K. After the processing plant had been cleaned and the wells were plugged and secured, the platform was removed during 2013.

Published 24. March 2017   •   Updated 25. October 2019
© Norsk Oljemuseum
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Base operations

person By Norwegian Petroleum Museum
All the supplies needed to ensure that the offshore platforms can do their job of producing oil and gas pass through the base at Tananger outside Stavanger. Warehouse operation at the base covers five main functions: goods reception, spare parts store, accounting, pipe store and goods dispatch.
— Phillips is about to establish themselfs at the Norsco base,1972 Photo: Norsk fly og flyfoto/Norwegian Petroleum Museum
© Norsk Oljemuseum

Dusavik base, 1966-73

The contract for Phillips’ first supply base in Norway was signed with Stavanger-based tanker company Smedvig Tankrederi on 25 April 1966.

It covered the hire of outdoor storage and quay areas as well as a new combined warehouse and office building which was modest by today’s standards.

Located at Dusavik just outside Stavanger, Phillips ranked as the first tenant at what was to become one of the two big offshore supply bases in the district.

The drilling operations which led to the discovery of Ekofisk were served from Dusavik. While the lease ran until 1981, it only functioned as the main base for the Stavanger area until 1973.

Rapid organisational growth made the premises in Dusavik too small by that year, and additional space was obtained by taking a clearly creative approach.

 

So Phillips secured premises in a soap factory, a Chinese restaurant and the bar and other areas of Stavanger’s Alstor Hotel. And many of those hired in 1973 are sure to remember that they were interviewed at the city’s Atlantic Hotel.

basevirksomhet, engelsk,
Hotel Atlantic. Photo: Asbjørn Jensen/Norwegian Petroleum Museum

Phillips base, 1973-81

Some activity had been established at the Aker Norsco base in Tananger during 1972, but it was not until the autumn of 1973 that the headquarters for Ekofisk was transferred from Dusavik.

basevirksomhet, 1976, engelsk,
The "H-building" (lower right corner), at Tananger. Photo: Unknown/Norwegian Petroleum Museum

That occurred with the occupation of the H Building at Tananger, where Phillips had signed a lease with the base company the year before.

This covered the hire of outside storage areas, quays, warehousing, a canteen and an office building – a complete supply base. All the buildings were purpose-built.

The lease gave Phillips an option to acquire the whole facility at a later date, which the company duly exercised in the summer of 1979.

To varying degrees since 1973, the operator has needed to lease both warehousing and offices from Aker Norsco – partly in temporary structures and partly in permanent premises.

From 1973 to 1976, exploration operations with the Ocean Viking rig continued to be run from the Dusavik base. The charter then expired, and remaining activities were moved to Tananger.

Lack of space at the latter premises meant that the training department was transferred to Dusavik and remained there until the lease expired in 1981.

Similar shortages meant extra premises had to be leased around Stavanger. This growing problem led to plans being laid from 1978 for a significant expansion at Tananger.

Phillips base since 1981

The new building was gradually occupied from December 1980 and formally opened in August 1981. Once it had been finished, the old H Building was completely refurbished to the same standard.

This expansion marked a significant improvement in working conditions for many employees, and helped to enhance efficiency by gathering much of the organisation under one roof.

The development was originally intended to meet all needs for office space, with the exception of the project department’s requirements.

However, it became clear even before the new building was occupied that this goal would not be reached. But it proved possible by and large to cease hiring space outside Tananger.

Løfteskipet Uglen i aksjon ved Norscobasen i juli 1980. Foto: NOM/Norsk Fly og Flyfoto Løfteskip, Uglen, Norscobasen,1980, phillips, sola, olje, inntekter
The crane barge Uglen in action at the Norsco base in July 1980. Photo: Norsk Fly og Flyfoto/Norwegian Petroleum Museum

To deal with developments in the supply services for Ekofisk, Phillips entered into a contract with Aker Norsco on the construction of a larger and more modern warehouse.

This building and associated offices were occupied in late 1982/early 1983, and were regarded as a model example for the purpose.

The waterflooding project on Ekofisk received a green light in 1983, which created the need for more office space to accommodate the project department.

Since a quick start was important, the new building in Tananger was ready three months after the contract with Aker Norsco had been signed.

Premises utilised by Phillips in the Stavanger area by 1988 comprised 20 000 square metres of offices, 10 000 square metres of storage space and 850 square metres of workshops. In addition came the offices at Munkedamsveien in Oslo.

Another new building opened at the Tananger base in July 1996, which meant the whole workforce was assembled on one site in two connected premises.

While the old offices covered 14 000 square metres, the new seven-storey building has an area of 11 300 square metres and provides 420 additional office spaces.

It also accommodates a 600-square-metre conference centre, as well as a gym and a swimming pool measuring eight by 12.5 metres in the basement.

The Tananger base was sold in July 1996 to Aker Base, including buildings, furniture and fittings, and the deepwater quay.

Activities at the base

The Phillips base at Tanager plays a central role in operating the Greater Ekofisk platforms. All necessary supplies allowing these installations to do their job pass through it.

Warehouse operation at the base covers five main functions: goods reception, spare parts store, accounting, pipe store and goods dispatch.

The spare parts store is managed with the aid of a comprehensive computer system with full information for offshore personnel to log on directly and check availability.

When goods are received at the warehouse, they are marked with a purchase number and all data concerning the order is entered. They are packed out, checked and sent for shipment offshore.

The workshop, located in the same building as goods reception, deals with such jobs as mechanical repair of diesel engines, pumps, valves, heat exchangers and compressors.

It also repairs base equipment, like forklift trucks, cranes and fire-extinguishing systems. In addition, the shop produces pipework, pressure tanks and other structural welding.

The head office for Phillips’ activities in Norway stands alongside the supply base for the platforms in the Greater Ekofisk Area.

basevirksomhet, engelsk,
In November 2004 ConocoPhillips opened its OOC (Onsore Operation Center) at Tananger. Photo: Kjetil Alsvik/ConocoPhillips
Published 29. July 2019   •   Updated 22. October 2019
© Norsk Oljemuseum
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