News // Incidental
Final rescue results of BP ultimate secret weapon "top kill" intervention in 24 hours
27 May 2010 , 08:26Upstream1871
UK supermajor BP will know in 24 hours if its latest attempts to rein in the blown out Macondo well in the US Gulf will be successful.
“It’s too early to know if it’s going to be successful,” BP operations head Doug Suttles said at 7 pm local time on Wednesday. Suttles said the well appears to be gushing mud and not oil, six hours into a “top kill” operation. "What you've been observing coming out of the top of that riser is most likely mud," Suttles said at a news conference broadcast from a Louisiana command centre. "We can't fully confirm that because we can't sample it,” Suttles said, adding that the operation can be termed a success when the well has been fully plugged and “stops flowing”. Heavy mud had been pumped into to the blown-out well through the blow-out preventer since 1 pm local time. Streamling live video of the top kill is available here.
Suttles said the operation was going “according to plan” and that it would continue into the night. BP will have to do additional pumping and monitor the pressure at various points along the subsea equipment, Suttles said. The UK supermajor has already pumped over 7000 barrels of water-based mud through the choke and kill valves at rates as high as 65 barrels per minute, Suttles said at a press briefing. BP brought in two pumping vessels with a combined 50,000 horsepower for the job and has used both, Suttles said. The Q4000 semi-submersible supply vessel, which is currently operated by Houston-based Helix Energy Solutions, is being used as the “command vessel” for the top kill. For a full, no-nonsense explanation of the top kill, check out the Oil Drum.
So far, BP has not added any bridging material to the mud but the necessary material is being stored in a subsea manifold and is ready if needed, Suttles said. In the operation, known as a junk shot, BP would pump chunks of rubber along with the mud to help clog the BOP and force the flow of mud down the well. At times during the crisis BP had said it would start its well control efforts with a junk shot, but, because a failed junk shot could clog the parts of the BOP needed for other interventions option, the company decided to start with a top kill. If the top kill successfully kills the flow, BP will likely follow the mud with cement to secure the well and could also add a second blow-out preventer for an extra measure of safety.
It does not appear the drilling mud has eroded the riser or increased the flow rate so far, but in a worst-case scenario flow could increase 15%, Suttles said Wednesday. If the top kill does not work, the UK supermajor plans to cut off the riser from the lower marine riser package (LMRP) and attach another dome to collect the flow. The device would be coupled to a flex joint above the LMRP with a sealing grommet to keep water out of the flow and control gas hydrate formation. In addition, the cap has valves to inject methanol or hot water into the production stream. BP has already lowered the LMRP cap to the seafloor so it could be deployed immediately after a failed top kill. Installing the cap would take about four days, Suttles said, and it could be in place early next week. The LMRP cap would allow BP to capture as much of the flow from the well as possible while it works on other options to kill the well, he said. He announced Wednesday that BP preferred option in that instance would be to add a second BOP on top of the first.
BP told congressional investigators that pressure tests on a drill pipe hours before the deadly explosion that caused the Gulf of Mexico oil leak flagged up a "fundamental mistake," a memo released by congressmen Henry Waxman and Bart Stupak said. Representatives Waxman and Stupak were briefed by BP about the progress of its internal investigation. The fundamental error the BP official referred to concerned the results of a negative pressure test. The BP investigator said that two hours before the explosion, as preparations were being made on the Transocean semi-submersible Deepwater Horizon to start negative pressure testing of the wellbore, the system gained 15 barrels of liquid rather than the five that were expected, indicating there may have been influx from the well. A cementer witness was quoted as saying. "The well continued to flow and spurted." The investigator said the pressure test was then moved to the kill line, where a volume of fluid came out when the line was opened. It was then closed.
At this time, pressure began to build in the system to 1400 pounds per square inch. The line was opened and pressure on the kill line was bled to 0 psi, while pressure on the drill pipe remained at 1400 psi. The BP investigator said this indicated a "fundamental mistake" may have been made here as this was an "indicator of a very large abnormality". However, once the pressure was bled off, work continued as normal - the line was monitored and by 7.55pm the rig team were apparently satisfied the test had been successful and started displacing the remaining downhole fluids with seawater. The memo, released late yesterday, did not indicate who made decisions after the problem was found. BP and rig owner Transocean both had supervisors on the rig when it exploded. BP would not comment on the memo. It had earlier stressed the report is preliminary and further work was needed. However, a Transocean spokesman appeared to blame BP for the disaster, telling Reuters: "A well is constructed and completed the same way a house is built - at the direction of the owner and the architect. And in this case, that's BP."
Details of events leading up to the blowout come as new information from the leaking well seems to confirm widely held suspicions within industry that problems with cementing played a key role in the 20 April blowout. The congressional memo said BP data showed that several problems were experienced with production equipment aboard the rig. Nearly five hours before the explosion, an unexpected loss of fluid was observed in the well's riser pipe. That suggests "there were leaks in the annular preventer," a rubber gasket in the BOP, the memo said. Waxman and Stupak together lead the House Energy & Commerce Committee's investigative subcommittee, which has reviewed over 105,000 pages of internal documents from BP, Transocean, cementing contractor Halliburton and BOP manufacturer Cameron. The memo said the BP investigation has also raised concerns about the maintenance history, modification, and inspection of the BOP. Officials from BP and Transocean are scheduled to testify before congressional panels tomorrow. The BP officials testified that unwanted flow in the well starting 51 minutes before the explosion. About 18 minutes before the explosion, abnormal pressure leaks of drilling mud were observed and the pump was shut down. "The data suggests that the crew may have attempted mechanical interventions at that point to control the pressure, but soon after, the flow out and pressure increased dramatically and the explosion took place," the memo said.
Flow from the Macondo well is not travelling up the main well bore, BP operations boss Doug Suttles said Tuesday, a revelation that would support theories that a cement failure played a part in the blowout. “We actually believe the flow path is between two strings of the casing and not up the main wellbore,” Suttles said. Suttles said BP could not be certain of the flow path but diagnostic tests on the well seem to indicate the flow is not coming up main bore. A veteran industry source told UpstreamOnline that the news about the flow path “almost certainly confirms” what many suspected, that problems with the annular cement around the production casing played a part in the blowout. In its internal investigation, BP also flags up cement problems, adding that the float collar initially did not operate as intended - it appears it took nine attempts with higher than usual pressures to get the float to bump. It also appears that the float test carried out after cementing may not have been definitive, flagging up concerns that the cement slurry mayhave been contaminated by drilling mud. Suttles also said that BP believes the greatest restriction on the flow of the well is coming from obstructions down hole from things like cement chunks. “In that space would be cement, would be the rocks from the formations we drilled through and other bits of restrictions,” he said.
BP has been able to measure the pressure on the lower portion of the well’s BOP and found that it was “considerably lower” than would be expected if the flow was rushing unimpeded to the surface, he said. Suttles said the obstructions in the well itself are the “most significant” restrictions to the flow rate, but that BP also believed that “some” rams on the BOP have closed but they are obviously not shutting off the flow. The obstructions in the BOP and the well itself will not hinder the top kill, Suttles said.
Meanwhile, it has emerged that almost half the syndicates in the Lloyd's of London insurance market have launched legal action against BP as it battles to limit the financial damage it faces from the spill. The syndicates are attempting to block efforts to claim on cover held by the rig operator Transocean. BP, which had no external insurance in place for the accident, is trying to claim up to $700 million through a policy held by Transocean. In legal documents filed in a Houston court, 38 separate Lloyd's underwriting syndicates plus a string of other international insurers affected by the disaster, rejected BP's claim. They have asked a US judge to declare the group has "no additional-insured obligation to BP" for the clean-up or for any damages resulting from the spill. The Lloyd's syndicates claim that BP's contract to lease the rig from Transocean specifies that its insurers would only be held responsible for damage to the rig itself - not for pollution caused by a leak from it.
The filing states: "Because liabilities BP faces for pollution emanating from BP's well are from below the surface and from BP's well, those liabilities are not within the scope of the additional insured protection." Lloyd's declined to comment on the case. As well as about half of the 78 syndicates that operate on Lloyd's of London, the lawsuit was also brought by Axis Specialty Europe, Berkeley Insurance Company, Houston Casualty Insurance Company and Zurich American Insurance Company. Phelps Dunbar, a New Orleans legal firm, is handling the case for the insurance group. It is believed that the Macondo spill will be the biggest loss in the energy market since the explosion of the Piper Alpha platform in 1988. Piper Alpha cost Lloyd's $8 billion between 1988 and 1992. Even if BP succeeds in its attempt to secure insurance, it will cover only a small portion of the total costs to it from the accident. Analysts for Swiss Re have estimated that the total insured losses from the accident could reach $3.5 billion. However, according to UBS, the final bill could be as much as $12 billion.
The Transocean semi-submersible rig Development Driller III out of a 22-inch casing on Friday and was continuing down hole at 11,000 feet below the drilling floor Wednesday on the first of two relief wells. Suttles said on Friday that the rig was “slightly ahead of schedule.” Transocean semi-sub Development Driller II is drilling ahead at 8650 feet, a joint information command spokesman said Wednesday. Both wells are planned for casing strings of 36, 28, 22, 18, 16, 13-5/8, 11-7/8 and 9-5/8 inches, the same string as the original Macondo well. Both rigs spud their wells about 3000 feet from the original Macondo bore. They will drill vertically to about 10,000 feet before directionally drilling to intercept Macondo at roughly 18,000 feet. Though the Development Driller III currently is drilling below 10,000 feet, a joint information command representative could not confirm that the rig had begun to drill directionally. Once either well intercepts the Macondo bore, BP can pump cement and plug the producing zone. Suttles said the company has no plans to ever produce from the Macondo well because it has been damaged beyond repair.
Coast Guard Rear Admiral Mary Landry said that a government team convened to estimate the flow rate for the well has not released their report yet. The report may take some time as the scientists have committed to have their findings and methodology peer reviewed. Suttles has stuck with BP’s estimate that the Macondo well is flowing 5000 barrels per day despite repeated questioning from reporters. He added that even if the well was flowing more than 5000 bpd, it was “nowhere near” the estimates put forth by some academics of 70,000 to 100,000 bpd. The riser insertion tube, which was funneling oil from the largest leak up to the Transocean drillship Discoverer Enterprise, captured 22,000 barrels of oil over eight days, Suttles said. The device was pulled from the riser last night as BP prepared for the top kill operation.
The Macondo well - a discovery well which was to be temporarily abandoned ahead of later completion as a subsea producer - had been drilled to 18,000 feet by the Deepwater Horizon. An explosion late on 20 April rocked the semi-sub before the rig was engulfed in flames. The rig sank on 22 April, extinguishing the blaze. Eleven of the 126 crew on board the Deepwater Horizon at the time of the explosion are missing, presumed dead. Relatives of the 11 held a private memorial service in Jackson, Mississippi Tuesday. Drilling giant Transocean has confirmed nine of its employees were among the missing. Two worked for services outfit Smith International and Schlumberger's M-I Swaco joint venture. BP has a 65% stake in Mississippi Canyon Block 252. Anadarko has 25% and Japanese player Mitsui the remaining 10%. All are liable for costs on a proportionate basis.
BP lifted the total bill for the clean-up to $760 million last week, about $22 million per day, which includes the spill response, containment, relief well drilling, grants to the Gulf Coast States, settlements and federal costs. Analyst forecasts for the clean-up costs and compensation for the spill off the coast of Louisiana have ranged to as much as $12 billion.
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