Byford Dolphin is a semi-submersible column-stabilised drilling machine owned through Dolphin Drilling, a Fred. Olsen Energy subsidiary, and currently contracted by BP to drill within the United Kingdom section of the North Sea.[3][4The rig has been registered with Singapore.[1 The rig has been involved in serious accidents, the most notable being the decompression explosion of 1983 which killed five workers and seriously injured one.
Description
Byford Dolphin drilling rig is an improved Aker H-3 model that was developed in 1974 by Aker Group at the Aker Verdal shipyard in 1974.[7Between 1974 and 1978 she was renamed Deep Sea Driller. Byford Dolphin is an overall length of 108.2 meters (355 feet) and a breadth of 67.4 meters (221 feet) and a depth that is 36.6 metres (120 feet). It has a maximal drilling depth that is 6,100 meters (20,000 feet) and is able to be operating at a depth of 460 meters (1,500 feet). As drilling rigs, Byford Dolphin is outfitted with cutting-edge drilling equipment and must be certified to the highest standards according to Norwegian law. Byford Dolphin is capable of operating using the use of its internal engine (to to counter shifts as well as ocean waves) However, to move long distances it has to be transported by specially-designed tugboats.
Incidents and accidents
Accident with a diving bell
5 November 1983, around 4:00 a.m. during conducting drilling at the Frigg gas field, which is located in the Norwegian sector of the North Sea, four divers were in a decompression room system, which was attached via an elongated trunk (a small route) to a bell for diving on the rig. They were helped by two dive tenders.[5One of the divers was about closing doors between the system and branch when it suddenly collapsed from an atmosphere of nine into one atmosphere within less than a tiny fraction of a second. The tender as well as the four divers were killed immediately; one tender suffered badly injured.
Byford Dolphin Accident.
The chamber of compression was in use at the time the incident occurred. D1-D4 are divers. and T2 are dive tenders. It is this area connecting chamber 1 to the bell for diving. The preceeding situation prior to the accident took place as follows The decompression chambers 1 and 2 were linked by a trunk, which was connected to a bell for diving. The connection was secured by clamps that was operated by two tenders who themselves were experienced divers. A third chamber was linked to this system , but not included. At the time the divers D1 (35 years old) and D2 (38 years old) were sitting in the second chamber at 9 atm pressure. The bell that was used for diving by the divers D3 (29 years old) and D4 (34 years old) was just being swung up following a dive, and connected to the trunk. When they left their wet gear inside the trunk, divers then made their way through the trunk and into chamber 1.
The usual procedure could be:
- Close the bell .
- The diving supervisor will then just a little bit increase the pressure on the bell to seal the door.
- Close the door that is between the trunk and chamber 1.
- Slowly reduce the pressure of the trunk until 1 atmosphere.
- Release the clamp to disconnect your bell and chamber.
The initial two steps were completed the first two steps had been completed and D4 was ready to complete step 3. However, due to some reason that is not known an individual tender loosened the clamp, which caused an explosions in the chamber. A huge blast shot out of the chamber into the trunk which pushed the bell back and hitting the tenders. The tender that had opened the clamp was killed while the other was badly injured.
The three Ds D1, D2 and D3 were subjected to effects from the explosive compression and ended up dying in the locations depicted in the diagram. Further investigation by pathologists from the forensic field discovered that D4, exposed to the most extreme pressure gradient, had violently explosions occurred because of the rapid and huge growth of internal gases. His thoracic as well as abdominal organs and his thoracic spine was ejected and so were all his legs. The remains of his body were removed through the small trunk opening that was left by the door to the chamber that was jammed that was less than sixty centimetres (24 millimetres) in the diameter. Broken pieces belonging to his corpse were discovered scattered around the rig. A portion was even discovered sitting on the derrick 10 meters (30 feet) just above the chambers. The deaths of the four divers was most likely quick and easy.
Medical research
The medical examinations were performed on the divers’ bodies. The most noticeable finding in the autopsy were huge quantities of fat in the large veins and arteries as well as in the cardiac chambers and intravascular fats in the organs, particularly the liver.[5The fat is unlikely to be embolic however, it could be “dropped out” from the bloodstream in situ.[5It is believed that the blood’s boiling destroyed the lipoprotein complexes and rendered the liquids insoluble.[5The lipids were insoluble.
Rigorous mortis appeared extremely strong.[5The hypostases (accumulations of blood inside organs internal to the body) are light-colored red and in two instances there were numerous hemorrhages found in the livers. All organs displayed large amounts of gas inside blood vessels. Additionally, scattered hemorrhages were observed inside soft tissues. A diver was carrying an enormous subconjunctival bulla (a blister that was found in the eye’s tissue).
Investigation
The inquiry committee that investigated the incident determined that the cause was human error by the dive tender opening the clamp. It’s not clear if the tender that closed the clamp prior to that the tube was stopped, did do so on the direction by his supervisor, or at an initiative on his own, or as a result of a miscommunication. The only communication that the tenders outside the chamber system could hear was via the bullhorn that was attached to the wall’s surface. With the constant noise of the rig and from the ocean it was difficult to discern what was happening. The fatigue from long hours of work also impacted on divers who were often working for 16 hours in shifts. Modifications to the “planned utilization of overtime” policy were made in the course of an investigations into this event.
The incident was also attributed to an engineering flaw. The outdated Byford Dolphin diving system, that was in operation since 1975, wasn’t fitted with fail-safe hatches and outboard pressure gauges or an interlocking mechanism that would prevent the trunk from opening even when it was in pressure.[10 Prior to the incident, Norske Veritas had issued the following certification rule: “Connecting mechanisms between bell chambers should be arranged so that they can’t be operated while the system is pressurized,”[11which is why it is necessary for such systems to be fitted with reliable seals and interlocking devices. A month after the incident, Norske Veritas and the Norwegian oil directorate declared the decision permanent for every bell-system.
Post-investigation
The findings from the inquiry were challenged The findings of the investigation were disputed, and a group divers came up with evidence with the aim of “find[ingjustice for everyone” of the members of the crew that comprised Byford Dolphin. The group was formed The North Sea Divers Alliance in the beginning of 1990 and currently fights to get compensation for divers who have been injured or killed on the Norwegian Sector of the North Sea.
Subsequent lawsuit
The North Sea Divers Alliance, created by the early North Sea divers and the families of those who were killed were still pressing for more information and during February of 2008, received an investigation report that revealed the cause was due to faulty equipment. Clare Lucas, daughter of Roy Lucas, said: “I could go as to claim that the Norwegian Government killed my father as they knew they were diving in an unsafe decompression chamber. The families of divers’ families eventually were awarded compensation through the Norwegian government in the 26 years following the incident.
Other incidents
- On April 17, 2002, a 44-year old Norwegian employee on the rig was hit by a head injury and died during the course of an Industrial accident. The incident resulted in Byford Dolphin losing an exploration contract with Statoil in which Statoil expressed concerns about the operation of the rig. The accident resulted in the company losing millions of dollars of lost income
More reading
- A script error – A record of the pioneer divers and offshore divers of the Norwegian continental shelf. It also includes an article about safety and responsibility.
- Haddow, Iain (27 March 2008). “Norway’s underwater “guinea pigs'”. BBC News Magazine (British Broadcasting Corporation). http://news.bbc.co.uk/1/hi/magazine/7314283.stm. Retrieved July 14, 2010. The news report about Byford Dolphin and other incidents occurring in the North Sea de:Byford Dolphin.
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