Is Offshore Oil Drilling Truly Safe?

[mheslep]

Astronuc found a some leak composition comments from a reporter (from PWB forum); I thought I'd explore the technical implications here:

I heard some discussion yesterday concerning Wereley's estimate.
[...]

Sizing Up The Oil Spill Hearings
http://www.npr.org/templates/story/story.php?storyId=126985080

HARRIS (NPR): Wereley went on to say that his own figures could ultimately come down from where they are right now because remember, as we've been saying, this flow is both oil and gas, and BP gave us a figure that suggests the mixture is something like three parts of gas to one part of oil down at the ocean sea floor.

Harris is the NPR reporter making that statement about the mix that "BP gave us". That's the only news report on the composition I've seen so far. Would be nice if Harris could produce more details: Is that the volumetric ratio really on the ocean floor, or measured on the the surface? If on the ocean floor how could they know? Does the estimate exclude other fluids, esp. sea water+mud?

If that 3:1 ratio is correct, measured at the leak (?) then the PIV estimate of 70,000 bpd of petroleum implies total fluid leak of 280,000 bpd (11 million gallons), gas*+petroleum? That seems bizarrely high given the 30,000 bbd production of nearby working wells, http://www.chron.com/disp/story.mpl/...n/7011584.html" . Also 1.1x10^7 gpd is 18 cubic feet per second emerging from the pipe, of what diameter?

*gas pressure at 5000' down ~2500 PSI, so it's expanding ~170X upon reaching the surface?

 

[turbo]

If that 3:1 ratio is correct, measured at the leak (?) then the PIV estimate of 70,000 bpd of petroleum implies total fluid leak of 280,000 bpd (11 million gallons), gas*+petroleum? That seems bizarrely high given the 30,000 bbd production of nearby working wells, http://www.chron.com/disp/story.mpl/...n/7011584.html" . Also 1.1x10^7 gpd is 18 cubic feet per second emerging from the pipe, of what diameter?

Remember that the nearby working wells have to pump the oil a mile vertically. Production rates metered at the rig are necessarily heavily influenced by head losses and fluid friction losses. This one is just ripped open at the well-head, and it appears that the reservoir is under some impressive pressure, at least until the natural gas peters out. So the volume comparison (working well to damaged well at the sea-bottom) has to be taken with a pretty big grain of salt.

 

[russ_watters]

First, a factual problem of the revisionist history variety to deal with:

Meanwhile: 1) the only rate estimate I've seen coming from people with experience in marine oil and gas is BP's estimate.

Not picking on you specifically - everyone, including the media is calling the 5,000 bbl/day estimate "BP's estimate". The 5,000 bbl a day estimate is *not* BP's estimate, it is the US government's (Coast Guard/NOAA's) estimate. Some people want it to be BP's estimate so it is easier to claim it is a fabricated number based on bias or even lies (fraud, as claimed before). Now certainly BP would favor low estimates, but a BP bias didn't factor into the creation of that estimate and doesn't even need to factor into BP's usage of that number because that number is still the US government's favored estimate:

Salazar [Secretary of the Interior] said the best estimates are that 5,000 barrels a day are leaking into the Gulf...

http://www.cnn.com/2010/US/05/20/gulf.oil.spill/index.html?hpt=T1

That said, people have alluded to but not thought through some clear "flaws" in the 5,000 bbl a day estimate. Let me finish the thought:

The NOAA/USCG estimate is based on surface measurements and is therefore not a leak measurement, but is rather a slick measurement. That's not a flaw it just means it is different from a measurement of the leak and cannot be taken to be a measurement of the leak. The media fed us that number as a "spill" measurement probably because they didn't think of the same issues we didn't initially think of:
1. Some fraction of the oil is not making it to the surface.
2. Some fraction of the oil is evaporating after reaching the surface.

But certainly the USCG/NOAA personnel who made the estimate wouldn't have made that mistake.

Note the Salazar paraphrase above uses the word "leak" - and this is why I prefer direct quotes to media paraphrases, because we don't really know if that word choice is accurate or is just sloppy journalism. If it is accurate, then I'd say it is all but certain the government has the size of the leak low because if the size of the slick is growing at 5,000 bbl a day, the size of the leak is probably several times larger. BP seems to be acknowledging this.

Now when playing the propaganda/blame game, it is important for anti-energy/anti-corporate people to jump on the highest possible estimate, so the 5,000 bbl a day estimate is characterized as "wrong" and Werely's estimates are "best". But the reality is that not only is there currently no reason to believe the estimate is wrong (within the context of the definition of the word "estimate", of course), but it is likely that the surface slick size is more relevant than the other three numbers (evaporated oil, oil remaining undersea, total). No doubt any proper report will discuss and attempt to pin down all four numbers, but the one that most directly affects ecological damage and cleanup that BP will be made to pay for and will affect residents of the Gulf coast most is the estimate of how big the slick is.

From the same article as above, he was making the talk show rounds with some new numbers yesterday morning:

Steve Wereley, a professor of mechanical engineering at Purdue University, told "American Morning" on Thursday the spill is much larger. He said the leak could be as high as 20,000 to 100,000 barrels a day.

Put into the same terms as his previous estimate, that's 60,000 +-67%. His estimate got slightly larger, but his uncertainty got vastly larger. My confidence level in that estimate was never very high due to immediate instinctive red-flags about how one could use a low-quality video clip to make such an estimate. This only increases my skepticism. But hey: I'm a capitalist, so I didn't fault BP for downplaying the leak size earlier for financial reasons and I don't blame Werely for getting his 15 minutes, while the getting is good, either. I do, however, blame the media for promoting Werely and not doing their homework on him and his estimates. It's kinda funny: reporters are supposed to get three independent confirmations of a fact before printing it, but one "expert" says something provocative and all of the sudden, its gosphel. If they were doing their jobs, they'd get themselves two more experts to make the same measurements and/or comment on the methodology Werely is using.

 

[russ_watters]

2) I have yet to see a description that makes any logical sense as to how particle flow measurements from a passive video can even begin estimate what is coming out of that pipe.

Agreed. I've done a fair bit of research on Wereley's method and it bears only passing resemblance to what he's saying he did for the gulf spill. The differences appear to me to be pretty major:

1. Low-speed photography, using a standard camera.
2. Poor light source (no laser or strobe light).
3. Opaque fluid.
4. No pre-selected, suspended particles.
5. No specialized depth-of-field focusing.
6. Uncertain opening size (even if he got the size right, breaking-off a pipe can change the geometry of the outlet).
7. Unstable flow.
8. Uncertain and inconsistent mixture of liquid and gas.
9. Uncertain camera angle.

 

[mheslep]

First, a factual problem of the revisionist history variety to deal with: Not picking on you specifically - everyone, including the media is calling the 5,000 bbl/day estimate "BP's estimate". The 5,000 bbl a day estimate is *not* BP's estimate, it is the US government's (Coast Guard/NOAA's) estimate.

Yes, I've been sloppy - got it right (quoted) in https://www.physicsforums.com/showpost.php?p=2726371&postcount=486"

 

[russ_watters]

...whereas the scientific community simply has less to gain or lose in terms of power and money.

I would not make that assumption, particularly since one scientist isn't "the scientific community". Werely licenses his patents to corporations who make measurement equipment. There absolutely is a financial incentive for him to raise his profile.

In general I find this all amusing, as the majority of what this site is dedicated to is subject to FAR less "proof" and certainty than HD video of a leak. Theories and conclusions in various branches of physics and astronomy, cosmology, and medicine are based on less. If Pfizer released an estimate with no data that pharmaceutical X follows kinetics Y, we would scoff. If based on the only publicly available information was analyzed by independent experts who believe that in fact the pharmacokinetics are rather, P, Q, or R, then one would tend to believe that they are more reliable.

That is a clear misunderstanding of how science works and a baffling mischaracterization of the level of proof in science. Nowhere else on this forum would such loose science as these made-for-tv blurbs by Werely be acceptable for posting. They would immediately be deleted for violating our guidelines regarding the requirement that sources be peer reviewed, published (or official) sources. Wereley's blurbs are not scientific research quality information.

 

[IcedEcliptic]

First, a factual problem of the revisionist history variety to deal with: Not picking on you specifically - everyone, including the media is calling the 5,000 bbl/day estimate "BP's estimate". The 5,000 bbl a day estimate is *not* BP's estimate, it is the US government's (Coast Guard/NOAA's) estimate. Some people want it to be BP's estimate so it is easier to claim it is a fabricated number based on bias or even lies (fraud, as claimed before). Now certainly BP would favor low estimates, but a BP bias didn't factor into the creation of that estimate and doesn't even need to factor into BP's usage of that number because that number is still the US government's favored estimate:

http://www.cnn.com/2010/US/05/20/gulf.oil.spill/index.html?hpt=T1

That said, people have alluded to but not thought through some clear "flaws" in the 5,000 bbl a day estimate. Let me finish the thought:

The NOAA/USCG estimate is based on surface measurements and is therefore not a leak measurement, but is rather a slick measurement. That's not a flaw it just means it is different from a measurement of the leak and cannot be taken to be a measurement of the leak. The media fed us that number as a "spill" measurement probably because they didn't think of the same issues we didn't initially think of:
1. Some fraction of the oil is not making it to the surface.
2. Some fraction of the oil is evaporating after reaching the surface.

But certainly the USCG/NOAA personnel who made the estimate wouldn't have made that mistake.

Note the Salazar paraphrase above uses the word "leak" - and this is why I prefer direct quotes to media paraphrases, because we don't really know if that word choice is accurate or is just sloppy journalism. If it is accurate, then I'd say odds are good the government has the size of the leak low because if the size of the slick is growing at 5,000 bbl a day, the size of the leak is probably several times larger.

Now when playing the propaganda/blame game, it is important for anti-energy/anti-corporate people to jump on the highest possible estimate, so the 5,000 bbl a day estimate is characterized as "wrong" and Werely's estimates are "best". But the reality is that not only is there currently no reason to believe the estimate is wrong (within the context of the definition of the word "estimate", of course), but it is likely that the surface slick size is more relevant than the other three numbers (evaporated oil, oil remaining undersea, total). No doubt any proper report will discuss and attempt to pin down all four numbers, but the one that most directly affects ecological damage and cleanup that BP will be made to pay for and will affect residents of the Gulf coast most is the estimate of how big the slick is.

From the same article as above, he was making the talk show rounds with some new numbers this morning: Put into the same terms as his previous estimate, that's 60,000 +-67%. His estimate got slightly larger, but his uncertainty got vastly larger. My confidence level in that estimate was never very high due to immediate instinctive red-flags about how one could use a low-quality video clip to make such an estimate. This only increases my skepticism. But hey: I'm a capitalist, so I didn't fault BP for downplaying the leak size earlier for financial reasons and I don't blame Werely for getting his 15 minutes, while the getting is good, either. I do, however, blame the media for promoting Werely and not doing their homework on him and his estimates. It's kinda funny: reporters are supposed to get three independent confirmations of a fact before printing it, but one "expert" says something provocative and all of the sudden, its gosphel. If they were doing their jobs, they'd get themselves two more experts to make the same measurements and/or comment on the methodology Werely is using.

Of all those involved, BP is like a shark, it does what you expect according to its nature. The MMS and politicians who only now find the ability to whine after allowing this to proceed for money's sake are the villains in this piece, if one wished to frame it in those terms.

Personally, who to blame is not something I care about, I am simply aghast at the massive use of toxic dispersants, and the environmental and economic impact. Who is at fault only matters in a world where justice can be done, and this is not that world. Reducing an environmental, personal, and economic catastrophe to a game of who did what and when is a distraction from the real issue.

That said, your views on Wereley who as Astronuc pointed out is already accomplished and published, has a far lesser stake in this than BP, and the various US agencies who are failing in their job. Your pondering is a bit of rearranging deck chairs on the Titanic, but then why discuss substance when we can speculate on speculations, denigrate the character of an academic you do not know, and simply "go limp" on the issue of ramifications as one is lost in the details of measurement.

For someone who is so laissez faire in their capitalism, you spend a great deal of time nitpicking media reports, and virtually none on the issue at hand: the safety of an endeavor for which reliable means of fail-safes were not developed. We get the notion of politics and blame, how about more in the realm of cogent discussion of the safety of offshore drilling at this depth, given the facts: a large leak, 600K gallons of toxic dispersant, and more? This isn't the "spin control" thread.

 

[russ_watters]

Yes, I've been sloppy - got it right (quoted) in https://www.physicsforums.com/showpost.php?p=2726371&postcount=486"

You've been letting the propaganda and poor reporting get to you.

 

[IcedEcliptic]

I would not make that assumption, particularly since one scientist isn't "the scientific community". Werely licenses his patents to corporations who make measurement equipment. There absolutely is a financial incentive for him to raise his profile.

He has already been wildly successful, with a co-author credits on the book of PIV (https://www.amazon.com/gp/product/3540723072/?tag=pfamazon01-20), and two widely used patents, and an associate professorship. If he is right, he may get more business, but he is exposing himself to being VERY wrong, and critique from such as you, which on balance seems to be a bad trade. BP and the US Government stand to gain a great deal by delaying and massaging data however, or as you pointed out, by simply NOT doing the proper study.

I wonder, if Wereley's estimate is finally confirmed, will you believe that it was just a lucky guess?

 

[mheslep]

Remember that the nearby working wells have to pump the oil a mile vertically. Production rates metered at the rig are necessarily heavily influenced by head losses and fluid friction losses. This one is just ripped open at the well-head, and it appears that the reservoir is under some impressive pressure, at least until the natural gas peters out. So the volume comparison (working well to damaged well at the sea-bottom) has to be taken with a pretty big grain of salt.

I believe the loss would be solely due to the fluid friction from the pipe. The 2500 PSI of ocean on the floor sees to it that the oil gets to the surface. Also I'm suspect that petroleum engineers understand the difference between surface and ocean floor flows.

More than half a dozen industry professionals who test wells flow and study oil formations were skeptical in interviews about estimates as high as 80,000 barrels a day, given the production rates of nearby deep water wells that yield 15,000 to 30,000 barrels a day.
“We work hard to maximize flow rates in deep-water wells and I don't know any well in the Gulf of Mexico that made that kind of rate,” said Stuart Filler, president of the Society of Petroleum Evaluation Engineers

 

[IcedEcliptic]

I believe the loss would be solely due to the fluid friction from the pipe. The 2500 PSI of ocean on the floor sees to it that the oil gets to the surface. Also I'm suspect that petroleum engineers understand the difference between surface and ocean floor flows.

They have failed to give a single explanation for the plumes, so... cite?

 

[IcedEcliptic]

A good motive for government to express outrage, money from all sides!

http://money.cnn.com/2010/05/21/news/economy/bp_wildlife/index.htm?hpt=T1

 

[mheslep]

They have failed to give a single explanation for the plumes, so... cite?

Eh? Cite what?

 

[turbo]

I believe the loss would be solely due to the fluid friction from the pipe. The 2500 PSI of ocean on the floor sees to it that the oil gets to the surface. Also I'm suspect that petroleum engineers understand the difference between surface and ocean floor flows.

You have a mile of head loss to contend with combined with friction between the viscous oil and the pipe wall. If you believe that oil rigs don't have to use pumps to bring the oil to the surface, I'd like to see you come up with some examples.

BTW, petroleum engineers certainly DO understand the difference, but they have a vested interest in minimizing the public's perception of the possible flow-rate of the spill. Their use of flow-rates from producing wells to cite a maximum possible flow-rate from this wide-open well-head is disingenuous, IMO. I'd like to see engineers like Wereley and the Woods Hole staff get their hands on raw data that BP is sitting on.

 

[IcedEcliptic]

Eh? Cite what?

Your suspicions and beliefs outlined in the preceding quote.

 

[IcedEcliptic]

A peer-reviewed group will measure flow. Ignoring the chattering politicians, this is an interesting take on the environmental impact beyond the gulf: http://www.cnn.com/2010/US/05/21/gulf.oil.spill/index.html?hpt=T1

 

[mheslep]

You have a mile of head loss to contend with combined with friction between the viscous oil and the pipe wall. If you believe that oil rigs don't have to use pumps to bring the oil to the surface, I'd like to see you come up with some examples.

Well I'm assuming the floor ocean pressure can be applied, either via pressing on the buried reservoir or other means. In that case, absent force to overcome viscous friction I grant is present, raising the fluid requires no external head pressure to rise all the way up the pipe just to the surface. At that point, the pump head required is the same as pumping from the surface at the desired rate, again neglecting the viscous friction from the pipe.

BTW, petroleum engineers certainly DO understand the difference, but they have a vested interest in minimizing the public's perception of the possible flow-rate of the spill. Their use of flow-rates from producing wells to cite a maximum possible flow-rate from this wide-open well-head is disingenuous, IMO. I'd like to see engineers like Wereley and the Woods Hole staff get their hands on raw data that BP is sitting on.

Yes everybody has a vested interest. Some of these petrol engineers might well like to see a competitor (BP) removed from the Gulf, who knows; we can play the motivation game forever. Wereley is not a petroleum or chemical engineer. Put his PIV technique in the hands of petrol/chemical engineer that knows something about spills, then I'm interested.

 

[mheslep]

Your suspicions and beliefs outlined in the preceding quote.

Meaning this?

Also I'm suspect that petroleum engineers understand the difference between surface and ocean floor flows.

I.e., I suspect they understand fluid mechanics.

 

[IcedEcliptic]

Meaning this?

I.e., I suspect they understand fluid mechanics.

Agreed, but nothing I've seen shows an accurate breakdown of the effluent. Are they capturing oil, and only a LITTLE is escaping, lofted by NG, or is 5000 bbl in a day a straight fraction of the total crude? If you don't know the composition of the fluid, or understand the role of pressure and temperature on the mechanics, then I wonder.

 

[Evo]

A peer-reviewed group will measure flow.

Can you post the link to that so the rest of us can read what you are referring to?

Thanks.

 

[IcedEcliptic]

Can you post the link to that so the rest of us can read what you are referring to?

Thanks.

It was in my previous link... http://www.cnn.com/2010/US/05/21/gulf.oil.spill/index.html

Meanwhile, the Coast Guard announced the creation of a federal Flow Rate Technical Group to assess the flow rate from the well. Coast Guard Capt. Ron LaBrec said that Adm. Thad Allen would oversee the team, which will include members from the Coast Guard, the Minerals Management Service, the National Oceanic and Atmospheric Administration, the Department of Energy, the U.S. Geological Society and others from the science community and academia.

The peer-reviewed team, which has already begun its work, is to determine the flow rate from the beginning of the incident to the present, LaBrec said.

 

[mgb_phys]

Currently only a rumor (http://adropofrain.net/2010/05/rumor-schlumberger-exits-deep-horizon-hours-before-blowout/)

But I have been on sites in the US where I have refused to go underground and I know people who work for Schlumberger and their company would definitely walk off a contract if there was any safety violation.

 

[turbo]

Well I'm assuming the floor ocean pressure can be applied, either via pressing on the buried reservoir or other means. In that case, absent force to overcome viscous friction I grant is present, raising the fluid requires no external head pressure to rise all the way up the pipe just to the surface. At that point, the pump head required is the same as pumping from the surface at the desired rate, again neglecting the viscous friction from the pipe.

This doesn't pass the straight-face test. Can you come up with a viable citation that claims that the static head of the oil in the pipeline is negligible and that minimal pump capacity is required to extract the oil? I'd love to see it.

 

[turbo]

Currently only a rumor (http://adropofrain.net/2010/05/rumor-schlumberger-exits-deep-horizon-hours-before-blowout/)

But I have been on sites in the US where I have refused to go underground and I know people who work for Schlumberger and their company would definitely walk off a contract if there was any safety violation.

Interesting. We'll see (when people are under oath months from now, perhaps) what happened. It would be refreshing to see a contractor walk off a job if they were unable to enforce a stop-work order due to unsafe conditions.

In my experience, Halliburton does not share that quality. I've been on pulp mill/paper mill shutdowns with them and was NOT impressed. Quick and dirty.

 

[tiresmokindad]

Yes Indeed. I agree that these will be a bad effect!

 

[Ivan Seeking]

The sickening videos and photos of heavy oil saturating critical marshes, wetlands, and beaches, are beginning to emerge.

http://www.vancouversun.com/news/soaks+into+Loisiana+bayou+admits+leak+heavier+than+first+revealed/3055732/story.html

"The oil that is leaking offshore, the oil that is coming onto our coast threatens more than just our wildlife, our fisheries, our coast," Louisiana Gov. Bobby Jindal said at a Saturday press conference. "This oil literally threatens our way of life."...

http://www.cnn.com/2010/US/05/01/louisiana.oil.spill/index.html

This is a video taken during a flyover of the spill. We can only hope the narrator is being overly pessimistic.

https://www.youtube.com/watch?v=uG8JHSAVYT0

 

[IcedEcliptic]

In the case of an offshore oil algae farm (vs ethanol) https://www.physicsforums.com/showpost.php?p=2692472&postcount=453" producing, say 1 million bbls per year, what's implicit in the process that would stop the same kind of disaster from happening in the case of an accident during a storm?

Hell, imagine what a tornado could do... lift a ton of the stuff and spray it everywhere. A hurricane would be even worse.

 

[magpies]

Isn't that what is going to happen with this oil spill come storm season?

 

[IcedEcliptic]

Isn't that what is going to happen with this oil spill come storm season?

It would seem likely, but there is no certain way to predict that.

 

[Ivan Seeking]

Oil from algae is just vegetable oil. It is non-toxic. You can drink it. And it degrades readily. Also, without a significant source of nitrogen and the proper temps, the algae won't survive in open water - that is, it wouldn't exist as a giant plume that kills everything else. If you have these conditions, you would already have an algae bloom, in most cases.

You would certainly have a lot of fish food!

Also, you wouldn't have millions and millions of gallons of oil leaking endlessly. You could only spill the oil that has been processed. The rest is still trapped in the algae.

Please continue the algae discussion here
https://www.physicsforums.com/showthread.php?t=211274

 

[Ivan Seeking]

Isn't that what is going to happen with this oil spill come storm season?

That is what worries me the most. All of these containment efforts will be useless if a siginficant storm hits the area. Hurricane season starts in one week. The water temps off the coast of NW Africa, the local hurricane nursery, are warmer than normal.

IIRC, when we see an ocean temp of 82 degrees F up through the Carribean, that's when the hurricane engine turns on. I'm not 100% sure of the number [maybe 81 degrees F], but it is surprisingly well defined.

 

[turbo]

Well, you have still not provided any information (even poorly-reviewed) about how oil from deep-sea wells magically rises to the surface, and how the production rates of existing wells can be used to limit the theoretical maximum outflow of a damaged well-head. I don't want to characterize another forum member as cheerleading for multinational corporations, but you seem to have moved beyond that to baton-twirling. Please link some peer-reviewed studies that show that the potential blow-out rate of a drilling-rig such as this can be characterized or constrained by the production rates of wells in nearby environs.

If the Deepwater Horizon spill can reasonably be constrained (in volumetrics) by the production rates of other wells in the same area, please show some evidence.

 

[RonL]

A link that will provide a simple and basic bit of info on oil and gas.

http://www.geomore.com/index.html



http://www.geomore.com/Oil%20and%20Gas%20Under%20Pressure.htm
http://www.geomore.com/Oil%20and%20Gas%20Traps.htm

It seems logical that the gas expands and pulls the oil upward on it's rise to the surface, also the oil is in it's own rights, a floating material.

 

[turbo]

Thanks, RonL. You have made my point quite well. Drill a hole into a pressurized deposit of oil and gas and fail to check it, and the flow rates can be quite spectacular. It is disingenuous in the extreme to cite the production rates of wells that have been in production for some time, and claim that their production rates set upper limits on the possible magnitude of this spill. They do not.

 

[magpies]

So has anyone figured out how big the field is yet? Is it still putting out oil like it was when they first showed video of it?