PIPER ALPHA JULY 6, 1988: THE WORST OFFSHORE OIL DISASTER IN HISTORY

January 27, 2019

The Piper oilfield is a North Sea oilfield covering 30.1 km2. It lies roughly halfway between Aberdeen and Bergen, at the eastern end of the Moray Firth basin.
Occidental Petroleum, Getty Oil, Thomson North Sea, and Allied Chemical, that later transformed into the OPCAL joint venture, obtained an oil exploration licence in 1972 and discovered the Piper oilfield in early 1973 after seismically mapping the area. Oil production started in 1976 with about 250,000 barrels per day. Oil extracted from it was piped to Scotland, where it was refined at a refinery on the island of Flotta, in the Orkney Islands, while gas was shipped via the Frigg gas pipeline. In June 1975, the Piper Alpha oil platform was placed over the field in 144 m of water, secured in place by 24 piles extending 116 m beneath the seabed. The platform was designed for simultaneous drilling and production. Piper Alpha became Britain’s biggest single oil and gas producing platform, bringing more than 300,000 barrels of crude a day – 10% of the country’s total. In late 1980, gas conversion equipment was installed allowing the facility to produce gas as well as oil.
On the evening of 06 July 1988, a condensate pump was isolated for maintenance on its motor drive coupling. The pressure relief valve had also been removed for maintenance and a blind flange fitted in its place. The flange was not, however, leak-tested or pressure-tested. When second pump tripped at about 21.45, the operators tried unsuccessfully to restart it. On 6th July the temporary blanking plate failed and a high pressure gas leak occurred. At about 21.45, the second condensate pump tripped. Shortly afterwards, gas alarms activated, the first-stage gas compressors tripped and the flare was observed to be much larger than usual. At about 22.00 an explosion ripped through Piper Alpha. The initial explosion in the gas compressor module caused a condensate line teeing into the main oil line to rupture in the oil separation module. Witnesses reported a second flash and bang as a huge fireball roared into the night sky. A massive fireball engulfed Piper Alpha. Machinery and steelwork melted and evacuation by safety vessels and helicopters became impossible.
Piper Alpha was so badly weakened by the intense fires that the topsides started to collapse. The main accommodation module, a four-storey building in which at least 81 men were sheltering, slid into the sea. All those inside died.
By the early morning of 07 July 1988, three-quarters of the original topsides, together with significant sections of the jacket, had been destroyed and lay in a tangled mass on the sea bed 140 meters below.
Of the 226 people on board that night, only 61 survived. Of the deceased, 109 died from smoke inhalation, 13 by drowning, 11 of injuries including burns. In 4 cases, the cause of death could not be established, and 30 bodies were never recovered.
It took over three weeks for the fires to be extinguished. The remains of Piper Alpha were toppled into the sea on 28 March 1989.
Piper Alpha was – and still is – the world’s worst offshore oil tragedy. The disaster led to insurance claims of around $1.4 billion, making it at that time the largest insured man-made catastrophe.
The Piper B platform was installed in 1992 to replace the Piper Alpha and commenced production in February 1993. Today owned by Repsol Sinopec the facility is located approximately 800 meters from the wreck buoy marking the remains of its precursor.
A memorial sculpture, showing three oil workers, was erected in the Rose Garden within Hazlehead Park in Aberdeen.