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You take a pole and poke a hole. This is the essence of oilfieldology. What I will try to lay out here is a simple explanation of how this is done with the understanding I have never worked offshore.
First of all, to dig a hole, one must be able to get the dirt out. The drill bit is always quite a bit bigger than the diameter of the pipe it is affixed to, and it has small holes, called jets, between the cutting heads. While drilling, fluid is pumped through the center of the drill pipe and comes out of the jets in the drill bit. All of the cuttings from the drill bits work are then carried toward the surface, flowing in the extra space between the outside walls of the drill pipe and the walls of the hole itself.
The first part of drilling requires no drilling mud. Water is sufficient for "red bed’ formations. A great big drill bit spinning fast makes short work of this. Eventually harder ground is found and changes are necessary.
The surface hole needs to be "cased." To keep it from falling in, casing pipe is put in place. It is just slightly smaller than the diameter of the bit, but much larger than the drill pipe. At the bottom of the casing is a plug with a big hole in it. As you run casing, the hole is full of water, the hole in the bottom of the casing allows the water in and allows the casing to sink
Once the casing is almost at the bottom of the hole (you don’t really want it setting on the hole floor) the cementing begins. Somebody with a slide rule and counting skills, figures out how much area exists between the outside casing wall and the actual hole wall. This is how much cement is pumped into the casing. A plug (more like a plunger) is placed on top of the cement and water is pumped behind the whole mess.
This forces the cement through the hole at the bottom of the casing and back up around the outsides, between the hole wall and the casing wall. The idea is to forever case the hole in steel pipe from the hole collapsing.
Now the process is the same, with some minor differences for intermediate and completion casing. Of course, the number one thing is high pressure gas that you done drilled into from coming to see you in a very rude fashion.
The magic is in the drilling mud. Brought by trucks (or boats) in 50 and 100 lb sacks, drilling mud is very expensive. Barite and Gel and Cypan and caustic soda and mica are just some of the dry ingredients that make up drilling mud. Gell makes it thick and slick, good for slicking up hole walls and carrying out cuttings, Barite is for weight, to hold done mother natures indigestion.
Weighted mud getting kicked around makes me nervous. Yes, mixed mud is weighed on a set of triple beam scales that would make a drug dealer green with envy. And you can watch weighted mud get kicked around. Mud levels are watch very closely because, well, if all of a sudden your mud levels are going up above ground, that means something below ground is coming to see you very soon.
Now with the Deepwater Horizon blowout, they had just cased and capped the well with cement and were replacing the drilling mud, you know, that which holds down high pressure gas, with saltwater, which was nearly 40 percent lighter.
They do this with pumps bigger than large trucks. Pumps that move volumes quickly. They depressurized about a mile of pipe by nearly 40 percent based on a cement plug installed by Halliburton. The Blow Out Preventers should have been able to catch this and shut in the well.
The floormotors ran away with the high concentration of natural gas. All of these are equipped with flapper valves on the intake for just this reason. I have so many questions and am not confident that any answers forthcoming will be credible in the face of liability exposures.
I hope this info is helpful and feel free to ask questions in the comments–I’ll answer them if I can.
88 Comments
Thanks, very interesting. Do you think blowouts like this are more about human error or some error in the design and technology of wells like these? Or is it impossible to say?
Yes. Both
Thanks OFG, per Jason a great read, recommeneded.
LMAO.
Ordinarily, what happens to the drilling mud, is it “lost” during the process or reclaimed?
(I heard reports that BP (and/or TransOcean) was trying to reclaim the mud on Deep Horizon.)
Sometimes people can be insulated by so many layers of safety devices and procedures, they lose sight of the peril they face. I say this as a general observation, not to cast aspersions upon those lost in the Gulf. But I have witnessed firsthand, on multiple occasions, supervisors so intently training people in safety procedures and policies, they entirely neglect to mention the specific danger they wish to avoid–one that a simple shortcut in procedures brings about an “oh shit” moment.
With the cost of drilling mud, it makes sense to reclaim it. An entirely different problem is “lost circulation.” A crack develops in the hole wall and your drilling mud is going to parts unknown. Doubly bad if it is weighted mud because you are fighting gas pressure.
OFG!! Perfect timing – as the Seminal page came up with this article’s title, I was listening to Rachel Maddow repeat, “we gotta cap that well.”
You demonstrate part of what I love about fdl – the range of expertise among regulars is just amazing.
Now, I will go back up the page and actually read what you wrote.
Thanks for this explanation, OFG. I’ve been trying to get up to speed on how this is done, and it’s hard to find a basic explanation of the problem and how people try to solve it.
One question that occurs to me is whether the BOP on the ocean floor could still operate after the drill platform sank, and thus deformed the pipe used for drilling. It’s not uncommon for bent pipes to make valves their connected to malfunction. Is this a design consideration, that you know of?
Well, capping this well will be tough. Whipstocking into the side of an existing well is surgery.
BOP’s are double tuff badass mammy jammies. Sometimes called Christmas trees, they are a totem pole of valves, each one designed for a different purpose. Pipe rams close and seal around the outside of the drill pipe. Blind rams will chop the drill pipe in half (or anything else) to shut in the well. The Hydrill will close around anything, even a six-sided Kelly. Many of these are doubled up on, sometimes tripled. But yes, one must be able to OPERATE them. The story Marcy linked to from the Houston Chronicle claimed a hydraulic leak was spotted on the operation of the BOP. They also claimed the BOP was recently tested.
Also, if the collapsing drilling rig fell on the BOP’s and bent and cracked the casing pipe the BOP’s are mounted to, rupturing below the well head and BOP, they are then above the problem.
There was something like a mile of pipe leading from that well up to the drilling platform. That’s a lot of weight, and a lot of torque, even if there’s not a drilling platform on the end of it. The obvious design goal would be to make sure the pipe bends much more easily than the BOP, but under the circumstances a hydraulic leak doesn’t seem like a surprising development.
I seem to remember people speculating that the concrete wasn’t completely set, or some such, indicating that could have happened.
I would look to the space between the hole wall and the casing. This was where the cement was supposed to be, as well and the avenue to the cap. Done properly, it holds. Done improperly, product (gas and oil) escapes around the outside of the pipe, where nothing is supposed to be.
Very helpful, OFG. Thanks.
What are we talking, cost-wise? I know, from working in the industry, they’ve got money, but I’ve got no clue what that means. And if the issue is them swapping mud for seawater too quickly, it is probably very important.
I’ve had dealings with Halliburton cementing casing before. I was consistently underwhelmed. Cement as thin as soup, employees that didn’t know the difference between come here an sic ‘em, days and days wasted because they pumped in way too much cement and you have to drill it out.
True, those same stresses could work on a weak or incomplete fill…
Beauty of a post OFG!
Reminds me of KBR, Halliburton’s old defense subsidiary. Some themes seem to repeat themselves, don’t they?
Thank you, thank you, thank you.
I’ve been wondering where you were, OFG. I’m so glad you explained this, although I need to read it a coupla more times to get it. But thank you.
This needs some publicity, folks, hit those Tweet and FaceBook buttons. We have the benefit of a real expert here, let’s be sure this gets the wide exposure it deserves.
I have never seen any invoices for drilling mud, but just the sense it is not mud until you make it so. It comes in sacks, like quickcrete, cement in a sack. You start with water for maybe 2000 feet. You case the hole and “mud up.” Add 50lb sacks of Gel, 100s of sacks all day. Your relief comes on and he does the same as does his relief. Very labor intensive. Barite, which is to increase the weight of mud to defend against gas pockets, is where the price goes up strong. Plus other stuff added as sealants and such. Thing of hole a foot across and 18,000 feet deep full of gravy. Gravy doesn’t cost much, but that kind of volume adds up, especially the labor.
I’m more curious as to whether this move, this cap and relocate, was something that cropped up. Something tells me it wasn’t a long planned process.
If they replaced the mud with seawater, and the seawater was cold and came in contact with cement still heating as it cured, could that be catastrophic?
I tried to show the space between the pipe and hole wall is what is important. I know a lot about drilling and what they call “exploration” but production, not so much. That’s a whole different deal.
And thanks for the props.
Greg Palast has a new piece up at Truthout. Lots of info that will be of interest. Here’s an excerpt:
Slick Operator: The BP I’ve Known Too Well
Wednesday 05 May 2010
by: Greg Palast, t r u t h o u t |
I’ve seen this movie before. In 1989, I was a fraud investigator hired to dig into the cause of the Exxon Valdez disaster. Despite Exxon’s name on that boat, I found the party most to blame for the destruction was … British Petroleum (BP).
That’s important to know, because the way BP caused devastation in Alaska is exactly the way BP is now sliming the entire Gulf Coast.
Both in Alaska, when the Exxon Valdez grounded, and in the Gulf last week, when the Deepwater Horizon platform blew, it was British Petroleum that was charged with carrying out the Oil Spill Response Plans (OSRP), which the company itself drafted and filed with the government.Last year, CEO Hayward boasted that, despite increased oil production in exotic deep waters, he had cut BP’s costs by an extra one billion dollars a year. Now we know how he did it.
As chance would have it, I was meeting last week with Louisiana lawyer Daniel Becnel Jr. when word came in of the platform explosion. Daniel represents oil workers on those platforms; now, he’ll represent their bereaved families. The Coast Guard called him. They had found the emergency evacuation capsule floating in the sea and were afraid to open it and disturb the cooked bodies.
This just in: Becnel tells me that one of the platform workers has informed him that the BP well was apparently deeper than the 18,000 feet depth reported. BP failed to communicate that additional depth to Halliburton crews, who, therefore, poured in too small a cement cap for the additional pressure caused by the extra depth. So, it blew.
Why didn’t Halliburton check? “Gross negligence on everyone’s part,” said Becnel. Negligence driven by penny-pinching, bottom-line squeezing. BP says its worker is lying. Someone’s lying here, man on the platform or the company that has practiced prevarication from Alaska to Louisiana.
Slick Operator: The BP I’ve Known Too Well – 6 hours ago
This just in: Becnel tells me that one of the platform workers has informed him that the BP well was apparently deeper than the 18000 feet depth reported. …
truthout – 12404 related articles »
t r u t h o u t | Slick Operator: The BP I’ve Known Too WellMay 5, 2010 … Slick Operator: The BP I’ve Known Too Well. Wednesday 05 May 2010. by: Greg Palast, t r u t h o u t | News Analysis. photo. I’ve seen this …
http://www.truthout.org/slick-operator-the-bp-ive-known-too-well59178 – 7 hours ago
I guess it could, but I don’t think heat exchange would’ve been the sole cause. They waited only 20 hours for it to cure. Somebody called it good. Seems like they would do this in stages. Little bit and check, little bit and check. I don’t know what standard procedures are offshore. You don’t play around with pressure.
Thanks, Oilfieldguy. This gives me a much clearer picture of the inner workings of the well-drilling itself (although I don’t grasp such things as how the drilling bit gets removed from the hole, if the casing pipe coming in after it is slightly smaller in diameter than the drill bit).
As I understand it (from reading over at The Oil Drum blog that librty linked to at some point), the major leak of oil is coming up between the casing pipe and the riser around it (which would presumably mean it has to be between the casing pipe and the hole, beneath the BOP, for the two miles of well drilled under the sea). And where the riser kinked in a couple of places when it fell is where the two major leaks are. They’ve just managed to attach a valve and close off the end of the broken casing pipe itself, but the two leaks in the riser continue.
But isn’t that the space where the cementing should have been blocking leaks? That is, between the casing pipe and the hole, under the sea? And does the limited volume coming from the casing pipe itself mean that the cement plug (and maybe remaining drilling mud) is holding, more or less, in what was to be the future oil/gas portal when this well was in production?
Finally, can you tell where the drilling mud they were displacing was, exactly (in the casing pipe itself?), and why they would have wanted to do that, rather than leave it there for the time being? [Would they have been pushing water down against the cement plug in the casing pipe - if that's where the mud was - to push the mud up and out?]
thanks ofg — tweeted, facebooked and highly recommended.
Yes, you sort of need to know how deep the hole is to figure out how much cement to use. Casing and cement crews never independently verified hole depth. We always told them. We would actually measure the pipe as we came out of the hole (called strapping) to give a depth tally.
OFG, thanks for this great work: you learned me.
OFG: Good read!
Here is some interesting stuff. The comments seem to be from people in the know and are informative.
http://www.theoildrum.com/node/6430
although I don’t grasp such things as how the drilling bit gets removed from the hole, if the casing pipe coming in after it is slightly smaller in diameter than the drill bit).
Ah, good catch and great question. To case a hole, all drill pipe must be removed from it. Once cased (say top hole casing–further drilling required) you go back in with a slightly smaller bit. The deeper you go, the smaller the bit.
Outside the casing should be sealed with cement. Any flood of oil coming from there is a bad cement job.
The only time you use drilling mud is when you are drilling. New hole is uncased hole, which at some point needs to be cased. when it is cased, that new casing is then full of drilling mud.
Oilfieldguy, thanks. My question is pretty basic. How can you expect cement to dry underwater? I assume there must be a series of cut off spots like you’d see a fire department to use to cut off water flow from the hydrant, but can you explain?
Great question, thanks Loo Hoo.
What he said:
DERRICKMAN CALLED THE DRILLER AND SAID HE NEEDED HELP, HE HAD MUD GOING
> EVERYWHERE, AND ABOUT THIS TIME THE DRILL FLOOR DISAPEARED, THEN THERE WAS
> AN EXPLOSION, THEN A SECOND EXPLOSION.
What I said:
Mud levels are watch very closely because, well, if all of a sudden your mud levels are going up above ground, that means something below ground is coming to see you very soon.
OFG: If you go to the comment by Mad Dog on May 4 at 3:41, he has a pretty good take on what happened.
Ah…, gotcha.
No wonder everyone’s talking about the cement job, then, if the leak is in fact coming from around the outside of the casing pipe… (which, if I’m understanding correctly, would appear to mean that the weight of the drilling mud – or lack thereof – in the casing pipe itself may not be the primary culprit here).
They are not drilling underwater, they are drilling underground. They have about a mile of water before they get to the ground.
Well how does the water not go underground?
I’m sure some does in the beginning. But once you have your first casing section in, it’s pretty well a sealed system all the way to the drilling platform.
Rec’d, ofg. My question — the quote above, from the end of your piece – I don’t quite understand. What’s a floormotor? On the floor of the platform? And I’m not sure what’s meant by “ran away with.” Meaning, the high concentration of natural gas caused, ummm, well, there’s where I’m confused. Can you clarify?
(Still, overall, very good explanation. And a flashback to my time in Western Okla. in the ’80′s gas patch, where every third guy I met seemed to be a mudlogger – presumably the guy keeping watch on that very important measurement you mention. And every other truck that passed me on the highways was carrying sacks of mud. And marked Halliburton or Dresser.)
Some good detail about why the rig would want to remove the drilling mud before leaving the site, from The Oil Drum:
The rig that blew was powered by what is termed “Diesel Electric” Big diesel engines turning generators for power. A massive cloud of natural gas spewed out of the well. It was in such high concentration, like shooting starting fluid into a breather, that the massive engines revved up, indeed screamed to destruction. They literally exploded so violently it blew them completely off the rig.
That was the ignition source for the fire. Every engine on the floor of a drilling rig (floormotor) has a flapper, a diaphragm that completely chokes off the intake just for this reason.
thank you OFG. as with many here, I have several reads ahead for me – but I’m getting it – thank you so much for taking the time to help us all
and thank you firedogs – great questions
This is a very enlightening diary. A ton of questions we all had answered, a fun read.
Thanks OFG.
Oh, rec’d.
I think I’m misstating this, by thinking there’s casing/production pipe inside the riser that’s above the seabed. In fact, it sounds like what’s inside the (about-two-foot-diameter) riser above the seabed is a drilling pipe only (which is what they just managed to seal with a valve), which is presumably what was being used to displace the drilling mud with water. Which means, I think, that the drilling mud was being displaced from the (about-7-inch-diameter) casing pipe sunk into the ground for two miles below the seabed and simultaneously from the riser around the drilling pipe above the seabed. Making it harder to know where exactly the oil is coming from – through the casing pipe, around the casing pipe, or both, before entering the riser above the seabed. If this is a more accurate description of what’s inside the riser above the BOP, then displacing drilling mud from inside the riser in this way would appear to have an effect on the back pressure on the cemented area around the outside of the casing pipe (as well as on the pressure inside the casing pipe itself), and thus presumably could be a contributing factor/primary culprit if the cement job around the casing pipe let go.
[I have the same problem, Loo Hoo, in visualizing a 'dry' hole all the way down to the oil, starting from above a mile of sea, especially one dry enough to cure cement. Hard to fathom without firsthand experience, like that which OFGuy has generously shared with us here.]
Ah. Thanks. I get it now. Appreciate your patience with my ignorance.
How unusual is the depth the Deepwater Horizon was drilling? Where would you put if between ‘everyday occurrence’ and ‘close to record-breaking depth’
VG post, OFG. I have learned a lot. One question: Are the diesel engines equipped with some sort of overspeed shutdown control, which acts as a govrnor; or, to use an automotive term – a ‘rev limiter.’ This type of device is standard (and required) equipment on generators used as emergency power sources for schools, hospitals, etc. The overspeed shutdown device is specifically designed to prevent an engine from spinning to destructive speeds.
Cement & Concrete do not “dry” they cure. It’s a chemical reaction.
Both cure harder (have higher compressive strength) if they cure under water.
If the cement (grout) has too much water, it can be weaker when cured.
The company man test of the cement is probably an on shore test of a “test cube” of cement. I don’t see any way to test the cement is actually in place around the casing.
The problem on the rig is the classical engineering problem:
“Cheap, fast and good,” choose any two.
Yes there is a speed limiter. It cuts the diesel fuel supply. Not much good when the intake air is pre-mixed with methane (fuel).
This is true. Think of it this way–traveling in high gear, you depress the clutch and put the transmission in 1st gear. When you release the clutch, no amount of governors or speed limiters is going to prevent the engine from wildly over revving. The analogy doesn’t quite work in this instance, but the effect is the same. The only way to stop an engine from “running away” on natural gas coming in through the air filter, is to literally strangle it to death. The flapper valve is not an automatic process, it has to be done manually. When the derrickhand noticed the rapid increase of drilling mud, the motorman should have instantly been standing by the flapper shut-off.
Nothing replaces the conditioned reflexes of a seasoned veteran in the moment of crisis.
Brilliant, OFG. Carry on, please!
One additional point about the “reclaiming” of the drilling mud and replacing it with salt water. Marcy Wheeler raised the issue in her comment above. In all my years of Terra Firma drilling, we never re-used drilling mud. The replacing of mud with seawater on the deep Horizon’s well was due to the cost of dealing with the mud at the production stage which may occur years later. It would be a minor nightmare and very costly.
The reason drilling mud is not re-used is two-fold. First, the properties of the mud (more accurately described as drilling fluids) is that it is very specific for the formation the rig is currently drilling.
For example, the mud on Deep Horizon was weighted at over 16 pounds per gallon. That’s some heavy ass shit. If you pump that into a new hole, you will blow out the sides and lose all your mud anyway. It is a very delicate operation to calibrate the weight of mud to hold natural gas outside of the hole wall and not overpower it to the extent you lose mud through the fissures the gas you seek lurks. This is why mud levels above ground are watched so closely. We always used the extremely high tech method of a large nut tied to a piece of rope dangled into the discharge mud pit.
The second reason mud is not re-used is because it needs to be kept moving. Drilling mud does’t look too good after it’s been sitting still for a while. It cakes up, develops a skin and just doesn’t really have a shelf life.
So they were not trying to save money by reclaiming and then re-using the drilling mud, but to keep the production crew from having to mess with the nasty shit after setting up for a year.
It seems the problem was with the cement job on the casing and well cap. They used nitrogen injected cement to fill voids in the lost circulation, gas-pocket kick zones. Problem is, that kind of cement isn’t real stout, the word foam is used a lot in describing it. Heavier cement might have pumped through the hole wall with no one being the wiser because you do not “fill it to the brim” on completion casing. The last thing you want is BOP’s full of cement.
So if I understand correctly, at accident time they were in the process of wrapping up the exploratory phase at this site and working towards moving the rig to its next site. Has anyone asked where the rig was going to next, and whether there was any unusual hurry/priority/pressure inside BP or Transoceanic about getting it there?
Excellent explaination in layman’s terms. Yah done good, OFG
Most excellent! OFG, you may take two backpats and an attaboy out of petty cash!
Boxturtle (Learned more from this thread than from all that has gone before)
Very happy to see this on the FDL front-page. Very well deserved, I hope it gets some more eyeballs among the chattering class, who surely need to know more about oildrilling than they do. I know this because I’ve been listening to them ‘explain’ this blowout best they can, and I learned more from reading this post than I ever knew beforehand after listening to Legacy Media for ten-plus days.
Well-written and well-explained, sir, thank you.
Underwater video of their plugging one hole. Apologies if a dupe.
What questions would you ask?
OFG!!
Long time no see and a GREAT post.
Right up yer alley.
That’s great video!
And hey, hasn’t Kevin Grandia posted here before?
I’m not sure if I read it at The OilDrum, or elsewhere, but SOMEWHERE I read a comment that the guys who OBSERVE and MONITOR the mud levels are contracted, expensive, and there’s pressure to get them off the clock and off the job to save money.
I recall reading that they HAD been relieved too soon, and that was part of the negligence of the situation.
No mud observers/monitors on the job.
Is this scenario possible, OFG, and if so, could the monitors BEING ON THE JOB have helped this incident?
Great, great read, thanks for sharing your expertise with us all . . . *bows*
That’s a great site, isn’t it. And I recall that comment, also . . . it IS a good read.
Thanks for highlighting it.
Ya know, Loo Hoo’s questions were on my mind, and your explanations REALLY clarify it all!!
A sealed system, for the most part, from the surface, thru a mile of ocean, and then 18K-30K feet (depending on who you believe) of earth’s crust.
Incredible pressures built up, not to mention the pressure of RELEASING that pressurized oil and gas below, and bringing it up (it expands!)(.
Incredible.
The gas from the drill hole got ‘OUT’ in the air on the oil rig? That gas then went into the air intake of the diesel engines, and revved them up????
Wow! How’d the gas get outside the closed system? Did it leak at the well head or up above on the platform somehow? (knowing gas expands A LOT from 18K down, up thru 5K of ocean, to surface pressure)
I don’t know about unusual, but there’s currently a global shortage of deepwater exploratory rigs like Deepwater Horizon — all of them are booked years in advance. The loss of Deepwater Horizon has likely goat-fucked a lot of people’s plans. Plus, on-site time costs of $35k+/hr have been quoted on the Oil Drum and elsewhere. Those two things together would light a fire under anyone’s ass.
OT Could the moderator please tell me why I get “you are not allowed to read drafts” on the next thread on the British election?
One ? OFG can this be fixed or are fucked and will this turkey just keep pumping out the OIL till no more is there?
~~~Repaired. Please try again.~~~
wow. excellent post by a hands-on worker. OFG, your explanation is appreciated, thank you for taking the time to write this. And what great questions and answers in the comments.
Actually, that’s not true at all. There will be a glut of these rigs coming into service in 2011. They were ordered during a period when deepwater drilling was the new thing to pursue owing to the high price of crude. Deepwater drilling is still the most profitable. Medium and shallow correspondingly less profitable.
Interesting post and comments, OFG.
Thanks OFG. Very informative, though you lost me a bit with this last part:
Are you saying it would have been better to use heavy cement? How do the BOP’s get full of cement?
Well, they’re not trying to save money by reclaiming the mud to reuse it.
They are trying to save money by swapping the mud out for water though. They don’t want to have to spend the additional time and money, which is apparantly significant, in cleaning it back out once the mud has settled and set up.
Thanks for this but not for the reason most think. For the trip down nostalgia lane when Oil was gold, earth milk, and Tulsa the “Oil Capitol of the World..” Your descriptions bring back memories of familiarity with all that equipment. I lived on 21st street about a mile and a half from the International Petroleum Exposition grounds. It was a time when to see a Halliburton truck was good luck.
Of course I had many friends in the oil business, including my very best friend who started life as a wildcatter in the by that time winnowing Oklahoma fields He did his own geology and most everything else. But, Lord! the romance of it all!. His wife and I spent more than one night out there all night waiting for the well to come in. It was a time when the stench of oil was uplifting, the sign of hope and prosperity, of greatness.
How things change. How perspective changes. Now we have come to risk the destruction of the planet as our greed and hubris grew from that romance. No one understands the life of the earth better than the geologists and paleontologists. I cannot believe that if they were still doing the exploration we would be in the mess we are.
Thanks for listening.
An entirely different problem is “lost circulation.” A crack develops in the hole wall and your drilling mud is going to parts unknown. Doubly bad if it is weighted mud because you are fighting gas pressure.
Could the loss of a mud “cap” have led to gas migrating up-stack? Could that have aggravated the loss of weigth of mud replacement?
Wicked cool post.
713
Sorry gang, I didn’t know they were going to front page this, or I would’ve been on hand to answer questions.
Larue @ #63: I read those reports too about contractor mud monitors being relieved and the question of a causal relationship. Of course, more eyeballs are better than fewer eyeballs, but the Derrickhand, a roughneck crew member, is the one who mixes and measures the mud. Of course, he is not a degreed geologist or a contracted mudlogger, but he is the hands-on person. He counts mudpump strokes per minute each hour and records them with pump pressure, mud weight and viscosity levels. When not tripping pipe in and out of the hole, the Derrickhand dotes on, creates and manipulates drilling mud properties. I have worked Derricks many times and have had geologists and mud loggers talk smack about my mud on rare occasions. I kicked 3 of them into the mud pits for giving me lip, and I never got run off for it.
Larue @ 66: Wow! How’d the gas get outside the closed system? Did it leak at the well head or up above on the platform somehow?
Yes. The The cap would’ve been below the sea floor and BOP’.
bmull @73: Tough call on heavier cement, since it could’ve just blew out the hole wall and not covered the zone of production–where the gas and oil was located. If you pump cement around the outside of the casing all the way to the riser pipe above the sea floor, then you are also in effect filling the Blow Out Preventers with cement as they too snuggle around the outside of the casing.
Poicephalus @ 76: They thought the well was secure with the cement cap. They did have some loss circulation problems during drilling, but they were done and replacing 16 pound per gallon weighted mud with sea water that weighs about 8.6 pounds per gallon. The downward pressure aiding the cap holding the well shut was in the process of being cut in half. They didn’t make it when she blew.
“What I will try to lay out here is a simple explanation of how this is done with the understanding I have never worked offshore.”
With a similar but unacknowledged caveat the Bush Administration devastated government, foreign relations, the economy and “truth and justice for all”, proving for all time that Benjamin Franklin was correct! Look it up!
ibid
So, what exactly does this mean, oldoilfieldhand? Thanks so much.
LINK.
Good find!
Seems there are numerous fails that caused this tragic mess. Wonder how many will be held accountable?
Deepwater Horizon Survivors Tell ABC News No Alarm Sounded Before Blast, Safety Gear Failed
LINK.
Thnx. I hope Oldoilfieldguy returns to this thread and provides some more remarks and clarification. Very interesting stuff.
just now sent him that NOLA link via his FB mailbox -
Cool, and thanks! There’s stuff coming out every hour it seems. I’m sure our Congresscritters will be right on it.
That particular Gulf region, apparently, is rich in unexploded ordnance.
“Two of the latest directives from the Minerals Management Service indicate a growing concern about Unexploded Ordnance (UXO) located in close proximity to deepwater exploration and development sites within the Gulf of Mexico (NTLs 2006-G12 and 2007-G01).”
LINK.
I am in no way an industry apologist, but it means we should wait until the investigation into the tragedy of the Deepwater Horizon in the Gulf Of Mexico that cost 11 men their lives and the families of those 11 men their husbands, fathers, sons, brothers, cousins and friends is complete. Period. I know exactly what goes on offshore in deepwater oil exploratory drilling, appraisal drilling and production drilling. I know because it is what I do and I couldn’t begin to tell you what went wrong, BECAUSE I WASN’T THERE!
I’ve flown in airplanes all over the world for 30 years, but I don’t speculate on what caused airline crashes. I won’t speculate on what happened on the Deepwater Horizon because it is a waste of time.
The men in control of the Deepwater Horizon were among the best in the industry. Deepwater oil exploration and production is complicated and everyone involved in the process is a dedicated professional.
The error or combination of errors that led to the explosion is documented. Whether it was an error in judgment, procedural error, communication error, equipment failure, outright negligence, or a combination, everything that happens “out there” is documented in real time.
The few people who are speaking to the news agencies were support personnel and probably didn’t spend much time in the Driller’s Console, the Toolpusher’s office or attend the daily briefings conducted by BP or Transocean every day.
If you’re hungry for information, here’s a fact you can chew on. The people in charge of the drilling program on the Deepwater Horizon survived the explosion. They know what hole and equipment problems the rig was experiencing before the explosion. They know the wellbore geometry, casing and cementing program, the results of the pressure tests on the seal assemblies and whether there were any anomalies in the execution of the programs. They know what BP directed them to do before the explosion. Here’s another fact you can chew on, the Driller and Toolpusher are authorized by the drilling contractor to take action without prior consulting the BP drilling representatives onboard if there is ever any question regarding the stability of the well or the safety of the rig.
My apologies as I had no intention of offending you. You are very knowledgeable about drilling for oil and I am very ignorant. And, with this tragic event, all kinds of stories are popping up all over the place. I brought a few of them here because because, while they are confusing to me, I thought they might be of interest to others, including you, and any comments those of you who are knowledgeable might care to make would be read and appreciated by those of us trying to understand. I certainly will trouble you no further. Peace.