Fascinating. Where did you get this? I really need the original source because I may write about it. If what you've posted is true, it goes to the level of safety and fail-safe used in such drilling, and points to a human error rather than a regulatory failure. If the leak is inside the casing, and not, as mentioned, broaching outside the casing, this points away from a cementing error. It has not been revealed by the press that there is currently no sign of leakage in the bore hole outside the casing.

I really need a source, please PM me if you don't want to release it publicly.

the reason they are not doing much in the presence of a gas cloud is because that's what blew up the Horizon
a bunch of natural gas came up the well and got sucked into the rig motors (think: train engines, only bigger), which caused them to "run away" (rev up until they blow up), which ignited the entire gas cloud coming up the well....





read a good explanation of a possible reason the cementing may have failed, indeed why cementing deepwater wells is so tricky, and it was a 2007 presentation by Haliburton

seems that, down in deep water where there's no light, it stays about 34F (the temp of max water density) and can remain that temp for several hundred feed underground

at that temp, methane can bind with water and raise it's freezing point to form ice crystals of methane hydrates
(if you've followed some of the science of Global Warming, you may recall that there are hydrates of methane locked into the Arctic permafrost that will be released as the climate warms - methane is a very potent greenhouse gas, and a large component of 'natural gas')

a well is drilled, then casing - steel pipe a little bit smaller than the drilled hole - is run down to keep the hole open permanently so it can flow oil back up reliably
the annular space (an annulus is a geometric shape like a donut) between the sides of the hole and the outside of the casing is then filled with cement grout to lock it in place

this is the "cementing the well" you've heard about in the news, and it's real tricky because they do it by computed volume - they take area computed by the diameter of the hole made by the drill bit, then subtract the circular area of the casing, then multiply that figure by the depth of the hole to figure the volume
then they pump a computed volume of cement down the casing until it goes out the bottom of the casing and starts rising back up in the annular space, hopefully to fill it, but not fill it to the BOP, where a bunch of mortar would not be a good thing

this pumping of the cement is VERY tricky, because the hole in the earth is not going through nice homogeneous rock, it's stratified and has different zones of material like sand and fissured rock and gas pockets which, unless the grout is mixed very carefully and pressures are controlled very precisely, will cause the cement to flow into the cracks instead of around the casing, thus increasing the volume of concrete needed to seal up the hole around the casing
you ultimately want the oil and gas to come up through the casing, not outside of it (a "Broach"), and you have to make the casing the path of least resistance, not the annular space where you want the cement

back to hydrates of methane: concrete cures by an exothermic chemical reaction - it creates heat
in fact, the fast-cure stuff they use to cement wells can get upwards of 200 degrees while it's hardening
this melts the ice crystals that contain the methane, which liberates the methane to go from liquid to gas
if you understand how boiling water works in pressure cookers, then you understand how boiling methane can raise pressures around the casing
pressure causes heat, and now you got a little bit of a chain reaction making more gas which makes more pressure which makes more heat which makes more gas....

this can cause the cement to be weakened with entrained natural gas, or can just blow it out of the hole altogether and sometimes up into the BOP, where it can jam a bunch of metal valves machined to high tolerances....

with all these variables, the ONLY way they have to test a cementing job is to pump the cement while watching pressures, let it set up, then pump high pressure water down there and see if they lose pressure, indicating a leak
then they pull a vacuum in the casing, and if they lose vacuum, it means there's a leak

apparently, the well passed these tests
but since it costs a million dollars a day to operate the Deepwater Horizon, they tested the cement job about 16 hours after they poured it, and the cement is gonna stay hot for 3-4 days while it sets up to max strength

apparently, when they pressure tested it to 10,000psi, they added heat to already hot cement - heat that dispersed away from the hole according to the laws of thermodynamics, and melted some more methane hydrates which was enough to start the chain reaction which resulted in a broach and subsequent explosion when methane gas came up the riser, blew out all the drilling mud and water in a geyser, and flooded the drilling floor with flammable gas which then got sucked up into the rig motors, and caused the runaways which blew the big engines off their mounts and set the whole rig on fire when they ignited the natural gas coming up



it does indeed look like Haliburton was at the center of this disaster, because they were the cementing contractors


it also looks like the oil companies lied to MMS and other agencies when they said that this drilling was almost foolproof

what's more, the area where the DH was drilling was a known deposit of methane hydrates

what's even more, the Beaufort and Chukchi Seas are loaded with them, as is ANWR - there is a high probability of a DH type blowout if they drill in the Arctic Ocean, and if you think cleaning up the Gulf of Mexico is gonna be tough, try the Arctic Ocean....

ScienceDaily (Mar. 19, 2009) - As the 20th anniversary of the Exxon Valdez spill approaches on March 24, WWF renewed its call for a time-out on new offshore oil development in the Arctic until technologies improve to ensure adequate clean-up of an oil spill. WWF is also calling on the Obama Administration to permanently protect Alaska's fish-rich Bristol Bay from drilling.

The Exxon Valdez oil spill in Prince William Sound, Alaska was one of the world's worst ecological disasters. A WWF report released March 19 demonstrates how the Arctic remains ill-prepared should another spill occur. The report, "Lessons Not Learned," finds that while practices have improved in Prince William Sound, oil spill response capabilities throughout Arctic region have improved little in the past 20 years.

By NOAKI SCHWARTZ and HARRY R. WEBER
The Associated Press
Published: May 7th, 2010 09:27 PM

ON THE GULF OF MEXICO - The deadly blowout of an oil rig in the Gulf of Mexico was triggered by a bubble of methane gas that escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before exploding, according to interviews with rig workers conducted during BP's internal investigation.

While the cause of the explosion is still under investigation, the sequence of events described in the interviews provides the most detailed account of the April 20 blast that killed 11 workers and touched off the underwater gusher that has poured more than 3 million gallons of crude into the Gulf.

Portions of the interviews, two written and one taped, were described in detail to an Associated Press reporter by Robert Bea, a University of California Berkeley engineering professor who serves on a National Academy of Engineering panel on oil pipeline safety and worked for BP as a risk assessment consultant during the 1990s. He received them from industry friends seeking his expert opinion.

Seven BP executives were on board the Deepwater Horizon rig celebrating the project's safety record, according to the transcripts. Meanwhile, far below, the well was being converted from an exploration well to a production well.

As the workers removed pressure from the drilling column and introduced heat to set the cement seal around the wellhead, the chemical reaction created heat, destabilizing the seal and allowing a gas bubble to form inside the pipe.

Deep beneath the seafloor, methane gas is in a slushy, crystalline form. But as the bubble rose up the drill column from the high-pressure environs of the deep to the less pressurized shallows, it intensified and grew, breaking through various safety barriers, the interviews said.

"A small bubble becomes a really big bubble," Bea said. "So the expanding bubble becomes like a cannon shooting the gas into your face."

...

Challenges

• Shallow water flow may occur during or after cement job
• Under water blow out has happened
• Gas flow may occur after a cement job in deepwater environments that contain major hydrate zones.
• Destabilization of hydrates after the cement job is confirmed by downhole cameras.
• The gas flow could slow down in hours to days if the de- stabilization is not severe.
• However, the consequences could be more severe in worse cases.

Deepwater Well Objectives
• Cement slurry should be placed in the entire annulus with no losses
• Temperature increase during slurry hydration should not destabilize hydrates
• There should be no influx of shallow water or gas into the annulus
• The cement slurry should develop strength in the shortest time after placement

Conditions in deepwater wells are not conducive to achieving all of these objectives simultaneously

piscator wrote:from Haliburton powerpoint presentation on the issues with methane hydrates inre cementing deep water oil wells:

"Methane hydrate is a solid form of water containing large amounts of methane in its crystal structure.

Methane hydrates are formed by migration of gas from great depths along geological faults, followed by precipitation, or crystallization, on contact of the rising gas stream with cold seawater.

Extremely large deposits of methane hydrates have been found under sediments on the ocean floors.

About 6.4 trillion tons of methane gas is trapped in deposits of methane hydrates."

-- F. Tahmourpour

Challenges

• Shallow water flow may occur during or after cement job
• Under water blow out has happened
• Gas flow may occur after a cement job in deepwater environments that contain major hydrate zones.
• Destabilization of hydrates after the cement job is confirmed by downhole cameras.
• The gas flow could slow down in hours to days if the de- stabilization is not severe.
• However, the consequences could be more severe in worse cases.

Deepwater Well Objectives
• Cement slurry should be placed in the entire annulus with no losses
• Temperature increase during slurry hydration should not destabilize hydrates
• There should be no influx of shallow water or gas into the annulus
• The cement slurry should develop strength in the shortest time after placement

Conditions in deepwater wells are not conducive to achieving all of these objectives simultaneously

Flash:

http://d1.scribdassets.com/ScribdViewer.swf#!flashvars#document_id=30867619&access_key=key-2d52ut706whd7hsf8ze0&page=1&viewMode=slideshow


PDF:

http://www.aade.org/houston/study/Fluid ... enting.pdf




world map of known methane hydrate deposits (image too large to post here):

http://walrus.wr.usgs.gov/globalhydrate ... browse.jpg


seismological inventory of "Flaming Ice":

http://soundwaves.usgs.gov/2001/02/research2.html

Hopeful Monster wrote:The methane hydrates might just bubble out on their own, given enough global warming.

Seth wrote:Now, if we could just figure out the technology to safely harvest methane hydrate...

piscator wrote:

Seth wrote:Now, if we could just figure out the technology to safely harvest methane hydrate...

looks like the Deepwater Horizon was doing a fine job before it flipped and sank....

Nonprofit Conservation Group Has Ties to Oil Interests, Gulf Oil Spill

With crude oil pouring into the Gulf of Mexico every day, the conventional wisdom about last month’s explosion and spill has been that this is an environmental disaster of unpredictable scale. The New York Times, in a story published today on Page One [2], challenged this conventional wisdom by citing several experts. One of those was from a nonprofit group called the Gulf of Mexico Foundation:
Continued here: http://www.propublica.org/ion/blog/item/non-profit-conservation-group-has-ties-to-big-oil-interests-gulf-oil-spill#0505updatezeller

Officials for BP on Saturday encountered a significant setback in their efforts to attach a containment dome over a leaking well on the seabed of the Gulf of Mexico, forcing them to move the dome aside while they find another method to cap the crude oil flowing into the Gulf since April 20

Alan C wrote:Indeed, there's probably going to be a bit of a mad rush to drill the Arctic areas.
Incidents like this don't exactly inspire confidence when drillers target ever more challenging environments in pursuit of diminishing returns.

BP: What We Know

--Before, during or after the cement job, an undetected influx of hydrocarbons entered the wellbore.
--The 9 7/8" casing was tested; the 9 7/8" casing hanger packoff was set and tested; and the entire system was tested.
--After 16.5 hours waiting on cement, a test was performed on the wellbore below the Blowout Preventer (BOP).
--During this test, 1,400 psi was observed on the drill pipe while 0 psi was observed on the kill and the choke lines.
--Following the test, hydrocarbons were unknowingly circulated to surface while displacing the riser with seawater.
--As hydrocarbons rose to the surface, they expanded, further reducing the hydrostatic pressure. The well flowed, and witness account suggest that the Annular Preventer in the BOP and the Diverter were activated.
--An explosion occurred, followed by a power failure.
--Witness accounts suggest that the Emergency Disconnect System was activated.
--The rig was evacuated.
--The BOP system failed to work as intended. Flow was not contained, and the Lower Marine Riser Package did not disconnect.
--Modiflcations have been discovered in the BOP.
--Leaks have been discovered in the BOP hydraulics system.
--BP launched an investigation which is ongoing.

Investigation Themes

--Cementing--design and execution
--Casing--design and installation
--Casing hanger--design and installation
--BOP-- configuration, maintenance and operation
--Well Control Practices.

We recently received a document from BP called “What We Know.” It was prepared on May 6 and it summarizes what BP knew about the spill at that time....

The first bullet says: “Before, during or after the cement job, an undetected influx of hydrocarbons entered the wellbore.” What this means is that there was a breach somewhere in well integrity that allowed methane gas and possibly other hydrocarbons to enter the well.

The second bullet says: “The 9 7/8” casing was tested; the 9 7/8“casing hanger packoff was set and tested; and the entire system was tested.” BP explained to us that this refers to a positive pressure test in the well. What this means is that fluids were injected in the well to increase pressure and to monitor whether the well would retain its integrity. The well passed this test.

Rigs like the Deepwater Horizon keep a daily drilling report. Transocean has given us the report for April 20, the day of the explosion. It is an incomplete log because it ends at 3:00 p.m., about seven hours before the explosion. But it confirms that three positive pressure tests were conducted in the morning to early afternoon.

The next bullet says: “After 16.5 hours waiting on cement, a test was performed on the wellbore below the Blowout Preventer.” BP explained to us what this means. Halliburton completed cementing the well at 12:35 a.m. on April 20 and after giving the cement time to set, a negative pressure test was conducted around 5:00 p.m. This is an important test. During a negative pressure test, the fluid pressure inside the well is reduced and the well is observed to see whether any gas leaks into the well through the cement or casing.

According to James Dupree, the BP Senior Vice President for the Gulf of Mexico, the well did not pass this test. Mr. Dupree told Committee staff on Monday that the test result was “not satisfactory” and “inconclusive.” Significant pressure discrepancies were recorded.

As a result, another negative pressure test was conducted. This is described in the fourth bullet: “During this test, 1,400 psi was observed on the drill pipe while 0 psi was observed on the kill and the choke lines.”

According to Mr. Dupree, this is also an unsatisfactory test result. The kill and choke lines run from the drill rig 5,000 feet to the blowout preventer at the sea floor. The drill pipe runs from the drill rig through the blowout preventer deep into the well. In the test, the pressures measured at any point from the drill rig to the blowout preventer should be the same in all three lines. But what the test showed was that pressures in the drill pipe were significantly higher. Mr. Dupree explained that the results could signal that an influx of gas was causing pressure to mount inside the wellbore.

Another document provided by BP to the Committee is labeled “What Could Have Happened.” It was prepared by BP on April 26, ten days before the first document. According to BP, their understanding of the cause of the spill has evolved considerably since April 26, so this document should not be considered definitive. But it also describes the two negative pressure tests and the pressure discrepancies that were recorded.

What happened next is murky. Mr. Dupree told the Committee staff that he believed the well blew moments after the second pressure test. But lawyers for BP contacted the Committee yesterday and provided a different account. According to BP’s counsel, further investigation has 3 revealed that additional pressure tests were taken, and at 8:00 p.m., company officials determined that the additional results justified ending the test and proceeding with well operations.

This confusion among BP officials appears to echo confusion on the rig. Information reviewed by the Committee describes an internal debate between Transocean and BP personnel about how to proceed.

What we do know is that shortly before 10:00 p.m.--just two hours after well operations apparently resumed--gas surged from the well up the riser and the rig exploded in a fireball....

Where's The Oil? Your Government Doesn't Really Know

By Dan Froomkin

First Posted: 05-13-10 06:02 PM | Updated: 05-14-10 08:01 AM

http://www.huffingtonpost.com/2010/05/1 ... 75647.html


For more than three weeks now, crude oil has been erupting out of a pipe a mile underneath the surface of the Gulf of Mexico. A new analysis of seafloor video indicates that nearly 70,000 barrels could be gushing out every day, NPR reports. That figure is at least 10 times the U.S. Coast Guard's original estimate of the flow, and "the equivalent of one Exxon Valdez tanker every four days."
And nobody really knows where it is, or where it's headed.

Federal officials are carefully tracking the trajectory of the oil that's made it to the water's surface and, increasingly, on shore. They even put out a daily map.

But there's never been an oil spill this big and this deep before. Nor have authorities ever used chemical dispersants so widely.

As a result, some scientists suspect that a lot, if not most, of the oil is lurking below the surface rather than on it, in a gigantic underwater plume the size and trajectory of which remain largely a mystery.

Oil on the surface can be fairly easily spotted by helicopter and satellite. But tracking an underwater plume is a much more complicated task, which thus far appears confined to one lonely improvising research vessel whose crew had been planning to hunt shipwrecks.

Rick Steiner, a University of Alaska marine conservationist who recently spent more than a week on the Gulf Coast, said the National Oceanic and Atmospheric Administration [NOAA] risks wildly underestimating the damage caused by the massive spill.

"If you don't look, you won't find, and they're not looking in the right places," Steiner told the Huffington Post.
Most major oil spills occur right at the surface, he explained. This one is entirely different.

With a spill this deep, the oil starts off extremely dense and under pressure. Some of it breaks up or dissolves into the water on the way up, and some of it makes it all the way to the surface. But some will "stabilize in the water column" maybe as low as 200 to 300 meters off the seabed, Steiner said. "Then it starts drifting with the current."

"I'm virtually certain that a lot of this oil hasn't even surfaced yet," he said. "What we don't know is the trajectory and direction of this subsurface toxic plume."

That's critically important information, both in order to assess what sorts of habitats the oil may be wiping out, and because "this stuff can pop up in surprising places, weeks if not months from now," he said.

Another aspect of this spill that's unusual is the widespread use of chemical dispersants, applied both at the source and on the surface. Oil sprayed with dispersants on the surface, for instance, breaks into small droplets -- which could then remain suspended in the water column, Steiner said.

Doug Helton, an emergency response coordinator in Seattle who is NOAA's trajectory expert, told HuffPost on Thursday that measuring and tracking the oil beneath the surface is beyond NOAA's abilities at this point.

"We have some ideas of how it's working," he said.

"We think that for the most part the oil is surfacing," he added. And referring to a video that shows oil billowing out and up from the pipe, he noted that "you can see it's not staying there."

But tracking oil underwater "is a harder problem because you can't just fly out with a helicopter to look at it or see it from a satellite," he said. "It's not a simple answer."

"We have models of how oil behaves when it releases from the sea floor," he said. The models suggest that the oil from this spill is spreading out in a huge cone, a mile high and about two miles across, initially. Then, he said "we can look at currents." But the currents are not uniform at different depths.

"We have some testing that's trying to understand what the fate of that oil is, subsurface, but that's a problem," he said. "It's a lot easier problem to model the stuff that's on the surface.

As it happens, science journalist Mark Schrope is reporting for Nature magazine from aboard the National Institute for Undersea Science and Technology research vessel Pelican, which is spending the week taking water samples in the Gulf.

"As far as we know, this is the only research ship working in the region, Schrope wrote on Monday.

The mission, evolving on the fly, is a daunting one for the team. Most of the scientists are doing work outside their normal bounds, and they're preparing to deploy equipment that in some cases they've never seen before. They'll be doing their best to fill a growing list of requests from colleagues for samples and data, all aimed at better understanding the spill and what it's long-term impacts might be.

On Tuesday, Schrope described finding "countless small dead jellyfishes known as by-the-wind sailors, or Velella vellela, and known to be susceptible to oil. Normally these animals, about the size of two fingers together, are blue and float on the surface with a triangular sail rising above the water. But those we see here are transparent and floating upside down, many stained with oil."

"So where is the oil now? " Schrope asked on Wednesday. "That's really the guiding question of the whole expedition. The team will not be able to say for sure this week what's happening."

And on Thursday, Schrope wrote about how the scientists were developing a hypothesis: That there's a layer of dispersed oil about two thirds of a mile down. "This could be coming straight from the... gushing well, where the response team is now adding dispersants directly, and prevented from surfacing by the ocean's complex interplay of currents, density differences, and other factors," Schrope wrote. He continued:

Eventually the team found that farther away from ground zero the layer was lower... This might show the oil, likely aggregated with plankton and other organic material, is settling out over time....

The team is now on a quest to define the bounds of this strange plume. NIUST chief scientist Arne Diercks compares the effort to hunting shipwrecks, which is one of the things the group would have been doing on this expedition if they had not been diverted to oil research.

Defining the plume will only tell a small piece of what's going on here, though. As for the larger questions of what will happen to the plume, how far it will drift, and what effect it might have on life in the deep, assuming it is in fact oil? "I don't know," says [Vernon Asper, an oceanographer with the NIUST team], "I just don't know. But that's why we're here."

FACT-MAN-2 wrote:This thing is really getting out of hand ...

Seth wrote:

FACT-MAN-2 wrote:This thing is really getting out of hand ...

It's never been adequately explained exactly where the leak is coming from. In the short video I've seen, it appears to be coming from a horizontal pipe with a crack in it. What I want to know is if it's possible to build a hydraulic pipe shear/crusher that could be dropped onto the pipe upstream of the leak to smash the pipe flat, thus either cutting off or reducing the oil flow, which is one of the safety devices that they supposedly have but did not install below the blow-out preventer. I'd love to see a drawing of the exact layout of the well, blow-out preventer and associated piping on the sea floor.