The world's worst offshore oil rig disasters
2 January 2014
http://www.offshore-technology.com/
Share on facebook Share on twitter Share on email Share on print More Sharing Services 0
The Piper Alpha disaster in the North Sea, UK, remains the worst offshore oil disaster in history
after 167 people lost their lives in July 1988. Offshore-technology.com profiles the world's worst
offshore oil rig disasters.
Piper Alpha, North Sea, United Kingdom
The Piper Alpha disaster in the North Sea, UK, which killed 167 people in July 1988, is the
deadliest offshore oil rig accident in history.
Discovered in 1973 and brought on stream in 1976, Piper Alpha was one of the biggest offshore
oil platforms in the UK producing more than 300,000 barrels of crude a day (about ten percent of
the country's total crude production). The offshore platform started producing gas in the early
1980s and had three main gas transport risers and an oil export riser before disaster struck,
destroying the entire facility causing an estimated loss of $1.4bn.
The Piper Alpha disaster occurred due to gas leakage from one of the condensate pipes at the
platform on 6 July 1988. The pressure safety valve of the corresponding condensate-injection
pump was removed during the day as part the routine maintenance of the pump. The open
condensate pipe was temporarily sealed with two blind flanges. The temporary disc cover,
however, remained in place during shift-change in the evening as maintenance work was not
complete. The condensate-injection pump was not supposed to be switched on under any
circumstances.
Communication errors however led the night crew staff at the platform to turn on the pump after
the other pump tripped. It resulted in leakage of gas condensate from the two blind flanges
causing gas ignition and serial explosions on the platform. Only 61 out of the 226 workers
survived the disaster and it took close to three weeks to control the fire.
At the time of the disaster the platform was managed by Occidental in block 15 of the UK
Continental Shelf, about 120 miles north-east of Aberdeen.
Related suppliers: Inspection, Maintenance and Repair
Alexander L. Kielland, North Sea, Norway
The Alexander L. Kielland was a semi-submersible platform accommodating the workers of the
bridge-linked Edda oil rig in the Ekofisk field, about 235 miles east of Dundee, Scotland, in the
Norwegian continental Shelf. The Platform, operated by Phillips Petroleum, capsized in March
1980, killing 123 people.
Only 89 out of 212 workers survived the accident and most died by drowning as the platform
turned upside down in deep waters. The platform capsized after the failure of one of the bracings
attached to one leg of the five-legged platform structure, after strong winds created waves of up
to 12m high on the day of the accident.
Once the first broke, all bracings attached to the leg failed in succession, the platform lost one of
its five legs and the entire structure tilted 30 degrees. Five of the six anchor cables snapped but
the platform was stabilised for some time by the remaining single cable, which ultimately
snapped.
Official investigation concluded that the root cause of the accident was an undetected fatigue
crack in the weld of an instrument connection on the bracing.
Seacrest Drillship disaster, South China Sea, Thailand
The Seacrest Drillship disaster in the South China Sea 430km south of Bangkok, Thailand, killed
91 crew men on the 3rd of November 1989. The 4,400t drillship was anchored for drilling at the
Platong gas field owned and operated by Unocal. The drillship was capsized by the Typhoon
Gay which produced 40ft high waves on the day of the accident.
The Seacrest drillship, also known as The Scan Queen, had been operational in the Gulf of
Thailand since 1981 as a drill ship for Unocal. The drillship was reported missing on 4
November 1989 and only found floating upside-down by a search helicopter the next day. The
capsize was believed to have occurred so quickly that there was no distress signal and no time
for the crew members to respond to the disaster.
Just six out of the 97 crew members onboard were rescued by fishing boats and the Thai Navy.
Apart from the severe weather condition the seaworthiness of the drillship was questioned as the
likely cause for the tragedy.
The ship also had 12,500ft of drill-pipe in its derrick, which was believed to have resulted in a
unstable high centre of gravity.
Related suppliers: Drilling and Well Completion
Ocean Ranger oil rig disaster, Canada
The Ocean Ranger oil drilling rig disaster which occurred in the North Atlantic Sea off the coast
of Newfoundland, Canada, on 15 February 1982 is one of the deadliest offshore oil rig accidents
in history. The offshore oil drilling capsized and sank killing 84 crew members onboard.
The semi-submersible mobile offshore drilling rig owned by Ocean Drilling and Exploration
Company (ODECO) was hired by Mobil Oil of Canada for drilling exploration well at Hibernia
field at the time of accident. One of the biggest rigs built by then, the 25,000t rig was 396ft long,
262ft wide and 337ft tall, with the capacity to operate 1,500ft beneath water and drill up to a
depth of 25,000ft below the seabed.
The rig was capsized due to a very strong storm which produced 190km/h winds and up to 65ft
(20m) high waves. On 14 February 1982, it was reported that a porthole window had broken and
water had entered into the ballast control room of the Ocean Ranger. The ballast control panel
was noticed to be malfunctioning two hours later.
Crew workers abandoned the rig and moved into the lifeboat stations but only one lifeboat with
36 crew members inside could be launched successfully. At least 20 crew were reported to be in
the water before the rig sank between 3:07am and 3:13am after staying afloat for about one and
half hours. Out of the 84 workers who drowned, 46 were Mobil Oil employees.
Glomar Java Sea Drillship disaster, South China Sea
The Glomar Java Sea Drillship disaster which took place on 25 October 1983 in the South China
Sea caused the death of 81 people when the drillship capsized and sank at depth of 317ft about
63 nautical miles south-west of Hainan Island, China, 80 nautical miles east of Vietnam.
The 5,930t Glomar Java Sea drillship was built by the Levingston Shipbuilding Company of
Orange, Texas, in 1975 and delivered to Global Marine. The 400ft long drillship was contracted
to ARCO China at the time of the disaster. The vessel had performed drilling for ARCO in the
Gulf of Mexico between 1975 and 1881, and operated off the coast of California for some time
before its arrival in the South China Sea in January 1983.
Operations ceased prior to the arrival of tropical Storm Lex as it approached from the east of the
drilling site. Global Marine's office in Houston, Texas, reported that the drillship was
experiencing 75kt (138.9km/h) winds over the bow, but the contact was abruptly lost.
No survivors were found in the extensive search operation conducted thereafter. The wrecked
drillship was found in an inverted position 1,600ft south-west of the drilling site. Only 36 bodies
were found, and the remaining 45 crew members were presumed dead.
Bohai 2 oil rig disaster, China
The Bohai 2 oil rig disaster in the Gulf of Bohai off the coast of China in November 1979 is the
sixth most fatal offshore oil rig disaster. It caused the death of 72 out of 76 people on board as
the Bohai 2 jack-up rig capsized and toppled in the sea water.
The accident was caused by a storm which occurred while the rig was being towed. Fierce winds
broke the ventilator pump of the platform causing a puncture hole in the deck resulting in
extensive flooding.
The loss of stability due to flooding coupled with severe weather conditions eventually led to the
capsizing of the jack-up. The accompanying tow boat could not rescue the crew members, who
were also believed to lack proper training on emergency evacuation procedures and the use of
lifesaving equipment.
The post-disaster investigations reported a failure in correctly stowing the deck equipment prior
to towing. It was also reported that standard tow procedures were not followed given the bad
weather conditions. The sunken jack-up rig was eventually salvaged with explosives by the
Yantai Salvage Company in April 1981.
Enchova Central Platform disaster, Brazil
The Enchova Central Platform disaster in the Campos Basin near Rio de Janeiro, Brazil, killed
42 people in August 1984. The accident occurred due to a blowout which caused a fire and
explosion at the central platform of the Enchova field operated by Petrobras.
Most of the workers were evacuated from the platform by lifeboats and helicopter except for 42
workers who lost their lives during the evacuation process. Malfunctioning of the lowering
mechanism of a lifeboat caused the death of 36, while six died as they jumped from the platform
into the sea. The lifeboat remained vertically suspended because of the failure of the bow hook
and eventually fell 20m deep into the sea as its supporting cables snapped.
Another disaster struck the Enchova platform on 24 April 1988 as one of its 21 wells blew out
and eventually ignited. The well suffered a blow out while undergoing a work-over to convert it
from oil production to gas production. The fire caused by the blowout on the platform led to
massive damage topside, however all the workers were safely evacuated to the nearby floating
accommodation ship without a single casualty.
The platform remained on fire for a month and Petrobras eventually drilled two relief wells to
control the blowout. The platform was declared a total loss and replaced by a new facility that
commenced production nearly 18 months after the accident.
Mumbai High North disaster, Indian Ocean
The Mumbai High North disaster on 27 July 2005 in the Arabian Sea, around 160km west of the
Mumbai coast, killed 22 people. Mumbai High North, one of the producing platforms of the
Mumbai High field owned and operated by India's state-owned Oil and Natural Gas Corporation
(ONGC), caught fire after a collision with the multipurpose support vessel (MSV) Samudra
Suraksha.
Strong swells, pushed the MSV towards the platform hitting the rear part of the vessel causing
rupture of one or more of the platform's gas export risers.
The resultant gas leakage led to ignition that set the platform on fire. Heat radiation also caused
damage to the MSV and the Noble Charlie Yester jack-up rig engaged in drilling operation near
the platform.
The accident caused significant oil spill and a production loss of about 120,000 barrels of oil and
about 4.4 million cubic metres of gas a day. ONGC opened a new platform at Mumbai High
North in October 2012.
Related suppliers: FPSO Vessels and Equipment
Usumacinta Jack-up disaster, Gulf of Mexico
The Usumacinta Jack-up disaster, which occurred on the 23rd of October 2007 in the Gulf of
Mexico, claimed 22 lives after a collision with the PEMEX-operated Kab-101 platform in the
Bay of Campeche.
The Usumacinta Jack-up was positioned alongside the Kab-101 platform to complete drilling of
the Kab-103 well. A storm with winds of 130km/h and up to 8m of waves created an oscillating
movement, which eventually caused its cantilever deck to hit the production valve tree on the
Kab-101 platform.
The collision resulted in oil and gas leakage leading to the closure of the safety valves of two
production wells at the platform. The crew members were, however, unable to seal the valves
completely, which resulted in continued leakage of oil and gas which eventually ignited causing
fires on the platform. 21 people were declared to have died during the evacuation and one worker
missing in the rescue operation was presumed dead.
The Usumacinta Jack-up also suffered two more fire breakouts in the month the followed, during
well control operations. The fire was, however, extinguished without any loss of life and
complete control of the well was achieved by the middle of December 2007. Approximately
5,000 barrels of oil was reported to have lost from the well without being recovered.
C.P. Baker Drilling Barge disaster, Gulf of Mexico
The C.P. Baker Drilling Barge disaster in the Gulf of Mexico on 30 June 1964 resulted in the
death of 21 people and injured 22 after fires and a explosion occurred on the drilling barge.
C.P. Baker Drilling Barge constructed Reading & Bates in 1962 was deployed for drilling
operation for Pan American Petroleum Corporation in block 273 in Eugene Island, Gulf of
Mexico, at the time of the accident.
The two 260ft long hulls suffered a blowout on morning of 30 June 1964. Water gushed into the
vessel through open doors on the main deck and the barge lost electric power soon thereafter.
The entire drilling barge was engulfed with fire and explosion just minutes of noticing the blow
out. Only 22 out of the total 43 crew on board survived the disaster, most of which saved their
lives by jumping from the port bow. The vessel sank upside-down in the water after heeling aft
for around 30 minutes. The rescue operation confirmed eight as dead and 13 crew missing who
were presumed dead.
Related content
Elgin-Franklin Offshore Field, North Sea, United Kingdom
Elgin and Franklin lie in the UK North Sea's Central Graben, approximately 240km east of
Aberdeen and in water 93m deep.
Atlantis Deepwater Oil and Gas Platform, Gulf of Mexico,
US
Considered one of BP's most technically challenging projects ever, the Atlantis platform is the
deepest moored floating dual oil and gas production facility in the world.
The Piper Alpha disaster is the worst offshore oil rig accident ever.
The Alexander L. Kielland disaster took 123 lives in March 1980.
The Seacrest Drillship disaster was caused by the Typhoon Gay storm in
the South China Sea.
The Ocean Ranger oil rig disaster offshore of Canada killed 84 people in
February 1982.
The Mumbai High North disaster in July 2005 took 22 lives.
Post to:
Delicious
The Usumacinta Jack-up disaster in the Gulf of Mexico killed 22 people.
Digg
reddit Facebook
StumbleUpon
Related Features
Follow Us:
Twitter
Facebook
Contact us
Advertise with us
Terms and conditions
Privacy
Links
Newsletter sign up
Online magazine sign up
offshore-technology.com is a product of Kable. Copyright 2014 Kable, a trading division of
Kable Intelligence Limited.