Wednesday, March 5, 2014
Sunday, September 26, 2010
Saturday, August 7, 2010
West Vanguard Blowout
According to Norwegian Petroleum Directorate records, Statoil's well 6407/6-2 was spudded by the Smedvig West Vanguard on 04 October 1985. The 36" top hole had been drilled down to 323m MDBRT with the 30" conductor set at 318m MDBRT. The blow-out preventer (BOP) had not yet been installed.
At around 2050 hours on the night of 06 October 1985 while drilling the upper Pliocene sediments of the 26" section, a drilling break was observed between 505-508m MDBRT with an ROP increase from 40m/hr to 712m/hr. Drilling was stopped at 523m MDBRT and the bit was pulled back 15m, after which the well began flowing and unsuccessful attempts were made to kill the well by pumping killmud. The bit had entered a shallow gas pocket at around 504m causing the well to blow out. A MAYDAY was sent from the rig at about 2310 and picked up by the Norwegian rescue center at Sola, which directed rescue ships and helicopters to the crew's aid.
With no BOP used for the top hole section, the flow of gas had been directed through the diverter system. This system was unable to contain the flow and the liberated gas exploded at around 2320 hours, engulfing the rig in a fireball. The one fatality is assumed to have resulted from this explosion, although reports indicate the victim's remains were never found. The rest of the crew were able to evacuate the rig in a matter of minutes using the fore lifeboats. The rig's deck structure, two of its legs and the engine room were damaged in the blast, resulting in the rig listing by 10 degrees.
By the following day, the fire had burnt out but gas continued to leak out of the well and bubble up to the side of the listing, fire-damaged hulk. Reporters flying over the rig noted a large hole in one of the rig's legs, extensive fire damage and a fallen crane.
After the accident, the rig was towed to Freifjorden near Kristiansund, Norway and investigated by Norwegian police and SINTEF (a Norwegian industrial research institute). The investigation revealed that gas initially leaked from the gasket between the riser and the slip-joint, forming a gas cloud on the cellar deck level which migrated into the shaker house via a poorly closed valve and travelled through an exhaust pipe, across the upper deck and into other rooms via air ducts before igniting. To quote the SINTEF report: 'Doors and hatches in and around the drilling module on the upper deck were knocked open in a pattern that gave indications of the course of explosions.'. The subsequent failure of the diverter system was attributed to the extreme flow of gas, drilling mud and sand, which eroded holes in pipe bends of the diverter system. Spurts of sand against the metal of the rig were suggested as one of the possible ignition sources of the gas cloud.
The rig was restored, returned to work and subsequently sold by Smedvig to Diamond Offshore Drilling Ltd. for US$ 68.5 million in December 2002. The rig was then renamed Ocean Vanguard, to fall in line with Diamond's rig naming policy.
After the blowout, Bergen Underwater Services (BUS) were contracted to locate the Vanguard's eight anchors, which had been cut and discarded to allow the Vanguard to be moved away from the gas blowout. BUS then deployed an underwater ROV from the M/V Arctic Surveyor to find the anchors. During the search, the ROV operator found a crashed World War II Heinkel He 115 on the seabed, which had been based at Trondheim, Norway during the Second World War. The plane had been cut in to two by the movement of one of the Vanguard's anchors. The full story of the Heinkel can be read at the NUAV Norway During WWII website.
Working offshore Louisiana, the crew of the Ensco 51 had just set casing when the well experienced an uncontrolled flow, causing a blowout and fire.
The 14-3/4" hole had been TD'd at 1700 ft and 10-3/4" casing run and circulated with no gas observed. The casing was then cemented and left to cure. In the early hours of 01 March, the casing was cut to length at surface and the slip-on wellhead positioned over the casing. Welding operations on the wellhead began, during which time a small blue flame was observed and extinguished. The source was thought to be grease. No gas was detected. Welding then continued and a second flame was observed, slightly larger than the previous flame. The area was again checked for gas resulting in the gas detector showing its maximum level. At 0130 hours, the driller observed flow from 10+ valve on the conductor below the platform.
Attempts were made to stem the increasing flow of gas and fluids from 10+ valve using sea water and weighted drilling mud but sufficient volume could not be added to slow the flow. The flow continued to increase and the decision was made to abandon both the rig and platform at 0300 hours. The 10+ valve was opened to divert the flow of gas away from the rig and platform, and all 43 personnel were then safely evacuated via two lifeboats to Platform B.
Specialist personnel from Wild Well Control were called in to help with capping and killing operations but the gas flow ignited in the early hours of 02 March, due to an unknown ignition source. The well partially bridged on 03 March, causing the fire to go out, and the well was subsequently killed. Production on the platform had been shut-in during drilling ops, which probably prevented a greater fire.
During the fire, the Ensco 51's derrick and substructure were completely destroyed, with the derrick collapsing onto the platform. The platform and its production equipment were also extensively damaged. In the 2nd quarter of 2002, Keppel FELS won the contract to upgrade and repair the Ensco 51 in Singapore for re-deployment in the Asia-Pacific region by November 2002.
In late-October 2007, the Usumacinta jack-up was positioned over the Kab-101 platform. Strong winds forced the jack-up off location, causing it to collide with the Kab-101 platform and rupture the platform's production tree. Twenty-two workers lost their lives as a result of the emergency evacuation in storm-force conditions. The leaking hydrocarbons ignited twice, causing major fire damage to both the Usumacinta and the Kab-101.
Friday, August 6, 2010
The offshore personnel did carryout their task in the face of harsh climatic conditions and rough weather to achieve desired results. However, it was the ill fated day of July 25th 2005 when South west monsoon was at its peak in Mumbai, a commercial capital situated on the west coast of India. The fury of nature was so severe and intense that it unleashed the rain that did not stop for 10 hours pouring 975 millimetres of rain. It inundated many apartments up to first floor level. It disrupted normal life as most of the telephone and power lines were damaged. Many people stranded in their respective places as all trains, buses, etc. remained non-operational.
The offshore oil field which is situated at about 150 Kilo metres away in the directions West North West from mainland was also experiencing very rough weather. A Multi Support Vessel was also carrying out its diving operations at a satellite platform. It was the human error and bad luck for a cook who severed his finger. It required immediate medical help. There was no doctor onboard. The day Master took a decision and abandoned diving operation. He also called the controlling platform for evacuation of the patient. The weather and sea conditions did not permit helicopter to land on board. Hence permission was granted and the vessel proceeded towards controlling platform for passenger transfer.
The weather condition was such that the swell height was 20-25 feet and continual squall and rain reduced the visibility to the barest minimum. The vessel positioned on the south face, abreast of the platform.The platform crane lowered the personnel basket and the cook was lifted up from the deck. At that crucial and critical moment, the vessel behaved in a very unusual manner. It made a contact with the platform and ruptured a 14"Gas Riser (Pipe carrying Gas). The phenomenal volume of Gas leak caught instant fire and the platform was engulfed in flames. The sequence of damage was so severe that oil carrying riser was also damaged leaking a lot of oil into the vicinity of the ill fated platform.
The chaos and commotion were taking its toll. The prevailing weather was adding fuel to fire. The People abandoned the platform and the ship. Life boats were launched and some people jumped into the sea. It was the old ship, and it has open life boats.The flames were very high reaching a height of approximately 500 feet.The debris was flying all-round. All offshore personnel remain adrift for few hours prior to been rescued by other vessels.The other unlucky one lost their life without any traced. Some dead bodies were also recovered subsequently.
The ship was burning and drifting. The diving superintendent took all possible measures pressurized to a maximum depth for safe recovery of divers in case the ship sinks. The Divers who were in the saturation chambers were left to their fate. However, destiny played a major role and luck was on their side. While the ship was a still burning and decompression process started. When they reached 30 metres of depth they were brought out safely and transferred to another diving vessel. They were finally brought ashore and told the trauma of seeing death in front of their eyes. The news flashed all over the world as it was the major oil platform disaster in the history of offshore oil industry in the world. On the other hand; the families were in a dilemma as no news of survivors could reach them until late in the evening.
It was the bad decision of one man that cost a huge loss of men and material, besides putting the financial burden on the Oil Company and reduction in production. Eventually, the ship sank and with it lost the vital clue. The sequence of events was never reconstructed and no debriefing was held. Hence all facts and figures were remained in the dark.
The trauma faced by the families was full of misery and hardship. The affected families and survivors were never been compensated as expected. The meager amount of compensation has not only been pathetic but also an insult to the humanity. It would have been better if things were more transparent and honestly made public. The inefficiency, careless attitude and corrupt practices of oil company personnel were the root cause of the disaster, consequently, affecting survivors and those families who lost the bread earners.
Thursday, August 5, 2010
There is a lot at stake offshore while planning installations, in this instance, the planning wasn't good enough.