[ROCKMAN]

Just to be sure everyone caught it: the well that scared the hell out of ExxonMobil (which has drilled HUNDREDS OF WELLS more complex then the Macondo well) was drilled in water TWENTY FEET DEEP. Trying to fight a blow out at the Macondo location was one of the toughest engineering nightmares a company has ever faced. Drilling wells in that geologic section that the Macondo penetrated was not that complicated especially when one considers the tens of thousands of similar intervals drilled over the last 50+:years.

[ROCKMAN]

OK, this will seem rather tedious. Skip if you want but be aware if you do you'll never understand what lead to the Macondo blow out.

NEGATIVE PRESSURE TEST
Most pressure tests performed on well bore seals, cement, pipe, valves, blowout preventers, etc. are either "positive pressure" tests or "negative pressure" tests. The term positive or negative describes in which direction you are testing the device.

Lets use for an example, a cement plug that has been installed inside a well casing to isolate 11,000 psi of reservoir pressure below the cement plug. Once the cement has hardened and set, you may want to perform both a positive test (from above) and a negative test (from below) on the cement plug. Let's assume the cement plug is located inside the casing at a depth that is 15000 feet below the place where the tests will be performed (the rig). Let's also assume that the casing is filled with a fluid of a certain density (15.4 ppg) that is exerting 12000 psi against the top of the cement plug.

Our test instructions for this well are to perform a 3000 psi net positive test and a 3000 psi net negative test on the cement plug. Before we begin the tests, the cement plug is being exposed to a 1000 psi positive pressure differential (12000 psi of well bore fluid hydrostatic pressure from above and 11000 psi formation pressure from below). You could say the cement plug is now under a 1000 psi positive pressure test because the pressure above the cement plug (12000 psi) is 1000 psi greater than the pressure below the cement plug (11000 psi). Therefore, to impose a 3000 psi positive pressure test on the cement plug, we would need to pressure up the top of the well bore to 2000 psi. At this point, the total pressure at the top of the cement plug would be 14000 psi, consisting of 2000 psi (pump pressure) plus 12000 psi (fluid column hydrostatic pressure). The pressure at the bottom of the cement plug would be 11000 psi of formation pressure, so the cement plug would be "tested" to a net 3000 psi positive pressure (3000 psi pressure differential from above).

Now lets perform the 3000 psi negative test (from below) on the cement plug. Remember that the cement plug is exposed to a 1000 psi "positive" pressure differential (from above) before we begin any pressure test. If we want to expose the cement plug to a 3000 negative test (from below), we must reduce the density of the fluid column above the cement plug such that its hydrostatic column will be 8000 psi. If we replaced all of the 15.4 ppg density fluid in the well bore (above the cement plug) with 10.2 ppg density fluid, the resulting condition would be exerting a 3000 psi negative pressure differential (from below) on the cement plug. (8000 psi hydrostatic column pressure from above, and 11000 psi formation pressure from below). If the cement plug held this 3000 psi "negative" pressure differential (from below), we would declare a successful negative pressure test.

So let's talk about the argument on the rig over the validity of the negative test. In reality interpreting the test data isn't simple as it seems above. The debate was INTENTIONALLY conducted in front of the entire crew coming on shift at the "morning meeting". Eventually when the one manager had his concerns rejected by the other he made this comment (it is on the record because it was INTENTIONALLY made in front of many witnesses):

"Well, I guess that's why we have blow out preventors."

That was not a casual remark. The translation: "If the situation goes sideways I'm going to burn you dumb f*cking ass". Seriously. I've seen fistfights almost start over such a statement. Once the Rockman had his consulting contract cancelled for saying it. Which was OK because he didn't want to go back living on an offshore rig that was operating dangerously. By the way it was reported that Schlumberger paid for extra choppers to get its hands of the rig ASAP because of safety concerns. Thus none of their hands were killed or injured.

OK, time for a second cup of coffee.

[ROCKMAN]

OK, as we say in Texas: it's time for the nut cuttin':

The cause of the blow out

Actually a simple explanation which no one can dispute. The cement pumped into the annulus from the bottom of the casing did not set hard. As mentioned before this not a rare event. So when a portion of the mud column (14.5 #/gal) was replaced with sea water (around 7 #/gal) the pressure at the base of the mud column was lower then the pressure in the reservoir containing the oil/NG. With the "green cement" (not set up) the hydrocarbons flowed down the annulus and back up inside the casing. Just as the laws of physics would predict: high pressure flows toward low pressure.

But understand the terminology: this IS NOT a blow out at this stage. The well is "taking a kick"...and not uncommon event that happens when drilling. And very uncommon when temporarily abandoning a well. So what's the primary indication a well is kicking? Again not rocket science: for the hydrocarbons to move upwards it has to push the mud out of the way. And how do we do a " FC"...Flow Check? When drilling you're constantly pumping drill mud down so the mud is continuously flowing out the top of the well. So while pumping it's very difficult the know the well is kicking. So a FC: you turn the pumps off...if the mud keeps flowing out of the well when the pumps are off you're taking a kick.

I know that sound simplistically stupid but that's how it been done on every well for the last 70+ years. Many times the Rockman was on wells where there was a serious potential for taking a kick. The good news there were automatic stopping points when a FC could be done: the drill pipe comes in 30' lengths. To add the next "joint" s have to turn the pumps off. When there was any kick concern the Rockman would have a FC done. And sometimes before "making a connection"...adding the next joint of drill pipe. Drilling at 10'/hour it can take 3 hours between connections. So just stop drilling for a minute, turn the pumps off and do a FC.

But big rigs, both on and offshore have a variety of monitoring systems...including alarms. But even if every system fails a visual FC can be done...in practice how it's usually done. And how: turn the pumps off and someone watches the end of the flow line carrying the mud to the mud tanks: if the mud keeps flowing out the well is kicking.

Yes, that f*cking simple and foolproof. So what went wrong on the Macondo well. The sad punchline coming next.

[ROCKMAN]

Controlling a kick

OK, you've done a flow check and determined the well was kicking: oil/NG rushing up the well bore...what do you do? First, you DON'T activate the BOP. Do that and you loose a variety of operational options..I'll skip the details. What you do is shut the well in. meaning you close the valve systems that prevent the mud (being pushed out by the flowing oil/NG) from being pushed up the inside of the DP drill pipe and the casing annulus. Yes, another annulus: the space between the DP and the INSIDE of the casing. Shuting the well in does NOT necessarily stop the oil and especially the NG from slipping up past the mud. But it does stop the hydrocarbons from flowing out the well bore.

So you now have a well shut in with explosive hydrocarbons trapped below the wellhead. At this point what do you do? First, you DON'T activate the BOP. Same reason as before. What happens: the tool pusher goes to his "kill sheet". Long before the incident developed such a theoretical situation is modeled and the details of the procedure to pump heavy mud down the drill pipe sufficient to stop the wild flow. Of course once the well is killed there's still oil/NG under pressure trapped below the wellhead. No problem: you slowly let the hydrocarbons flow out: the oil to the rig tank and the NG to the flare line where it is burned off away from the rig. So again this wasn't a " blow out"...just a "well control situation". And it was handled. The mud program is adjusted and you go back to drilling. Of coarse after all the floor hands change their underware? And you might wonder where the Rockman and other nonessentials are when the well is being killed after taking a hard kick: at our designated lifeboat station waiting to see if the abandon ship siren goes off. The Rockman has done so more then once. LOL.

Now here's the most difficult aspect of the blow out to understand. Maybe the monitoring system failed...not really clear. But even if it did there are 2 or 3 hands responsible for watch the mud returns. And remember there was a very serious argument about the cerment holding. Why didn't the manager who was concerned make sure there was a visual watch on the mud returns? I'm not being a smartass: they could have stationed a 10 year old to watch the return mud flow line and tell someone if the mud kept coming out when the mud pumps were turned off. That would have prevented the worst oil patch disaster in history.

And it gets worse: someone did see the well was kicking and unloading the mud. And he wasn't even on the rig...it was a the captain of a supply boat tied off to the rig. They were pumping mud from the rig tanks to the boat tanks to use on another well. He called up to the rig and told them to stop pumping the mud...his tanks were full. They told him he was wrong because the rig still had a !of of mud left in its tanks. They were wrong: the rig tanks were being refilled by the mud being pushed out by the kick.

And then the oil/NG blew though the return lines and wellhead. Sparks from somewhere set it off. Now they have a catastrophic blow out complete with death and destruction. And note: the blow out wasn't caused by a failed BOP because, first, no one attempted to activate the BOP that sat a mile below the rig on the sea floor. Second, even if they had it would not have stopped the explosion on the rig.

But the BOP did fail, probably as a result of the explosion on the rig and the down hole pressures from the kick. It was this BOP failure that allowed many millions of gallons of oil to spill into the GOM. So no: the BOP failure DID NOT cause the blow out. But it did fail to prevent the oil spill.

I'll pass on the details of the drilling of the kill well. Important but has nothing to do with the cause of the blow out or the oil spill. Based in what I've seen of the movie I seriously doubt it will provide a clear explanation of what happened. Probably for good reason: folks would walk out half way through due to boredom. But they would hang around to watch hands on fire jumping into the water.

Questions?

Speaking of heroics: some years ago the Rockman was on a rig about 12 miles away from a other rig taking a hard kick. Couldn't control it and couldn't activate the BOP remotely. The survivors reported last seeing the head drilling super (who the Rockman slightly knew) running under the drill floor. Presumably to manually activate the BOP. He apparently couldn't and an explosion ensued. He wax presumed killed because no body was recovered. As we say: sh*t happens.

[rockdoc123]

Rockman...keep the faith. I argued on this forum and at the Oil Drum that most of the "conspiracy theory" suggestions flew in the face of what was actually going on and the knowledge people in the industry have about what was actually happening. Some of the comments from people who know nothing about oil and gas who suddenly "knew" what was going on made me shake my head. As predicted the well was brought under control. The intervention plan was a good one and was executed properly.
This issues regarding why it happened are something else and I believe largely due to bad rig management.
Having served my time on an offshore rig jacked up on a pinnacle reef surrounded by 10,000 feet of water when it we had an underground blowout (human failure due to Ramadan stress was the root cause analysis) I know the drill, scary but your time is spent fretting but rather dealing with the issues, trying to figure out what went wrong, where the problem zone is and where you are going to get enough barite.
It seems most non industry folks think all of this is a disaster that has never happened before and there are standard protocols to follow.

[StarvingLion]

folks would walk out half way through due to boredom.

Well, gee whiz, what do these imbeciles get out of any of these scams (movies)? The only point of these scams is to depict people smoking.

[ROCKMAN]

A side note. Just saw a TV report about HUET certification...Helicopter Underwater Escape Technique. If you saw the movie "Top Gun" you might recall the scene where pilots were dumped upside down in a pool strapped in a jet simulator to practice underwater escape. To work offshore the Rockman had to get HUET recertified every 5 years. Not nearly as much fun as Cruise made it look like. LOL.

But it reminded me of the 11 killed on the blow out. As dramatic as that might seem being on a rig is not the most dangerous part of the job. It's the chopper flights to and from the rigs. The majority of offshore hands are injured/killed happens on those flights. About the time of the blow out 22 hands died in a chopper crash. And it didn't happen in the Gulf. Happened in the swamp just minutes away from the chopper base. They think it hit a flock of geese in the fog.

[hvacman]

A side note. Just saw a TV report about HUET certification...Helicopter Underwater Escape Technique. If you saw the movie "Top Gun" you might recall the scene where pilots were dumped upside down in a pool strapped in a jet simulator to practice underwater escape. To work offshore the Rockman had to get HUET recertified every 5 years. Not nearly as much fun as Cruise made it look like. LOL.

But it reminded me of the 11 killed on the blow out. As dramatic as that might seem being on a rig is not the most dangerous part of the job. It's the chopper flights to and from the rigs. The majority of offshore hands are injured/killed happens on those flights. About the time of the blow out 22 hands died in a chopper crash. And it didn't happen in the Gulf. Happened in the swamp just minutes away from the chopper base. They think it hit a flock of geese in the fog.

GREAT thread follow-up, RM. Thanks for your efforts to to further educate us all. It brings back memories of your compelling real-time posts on TOD in the midst of the Macondo blowout. One small possible factual error - related to cinematography - not petroleum engineering. I think that movie with the ejection seat evacuation training upside down in the water was "An Officer and a Gentleman", not "Top Gun". Both about naval aviators, but heart-throb-Richard Gere, not Tom Cruise.

[ROCKMAN]

Thanks H-man. Memories fade. Might be due to swallowing too much water at my last HUET cert. And didn't happen in the chopper dunk. Tested with the survival floatation siut: put it on - jump into pool - hook arms with other hands. No problem at that point but then had to take off and put suit back on while in the pool. Swallowed so much chlorinated water had to pull off the road half way back from Galveston and puke. LOL.

[StarvingLion]

Thanks for your efforts to to further educate us all.

hvacman, do you even know that there are 2 different reports on the internet for download that are longer than 126 pages and chock full of graphics and detailed explanations?

Final Report on the Investigation of the Macondo Well Blowout (126 pages)

Nobody will learn anything from The RockPuppets 1 page long useless drivel with no drawings.

[ROCKMAN]

"...useless drivel with no drawings." Of course no drawings: the Rockman posts info for ADULT consumption. He leaves the cartoons for the consumers of "Sesame Street". LOL.

And I suspect that most here who would take the time to read the Rockman's "drivel" won't take the time to read a 126 page report. But maybe the pissed off kitty would kindly present the group with a concise summary of that report since he has such a good handle on the subject. Cut and paste is acceptable. The group I'm sure gives thanks in advance.

[hvacman]

"...useless drivel with no drawings." Of course no drawings: the Rockman posts info for ADULT consumption. He leaves the cartoons for the consumers of "Sesame Street". LOL.

And I suspect that most here who would take the time to read the Rockman's "drivel" won't take the time to read a 126 page report. But maybe the pissed off kitty would kindly present the group with a concise summary of that report since he has such a good handle on the subject. Cut and paste is acceptable. The group I'm sure gives thanks in advance.

+1:)

[ROCKMAN]

H-man - I skipped at lot of side issues like the quality of Hallibuton cement, legal issues, well capping, spill clean up, etc. I suspect much of that long report goes into those details.

But I've worked tens of thousands of hours on offshore rigs so I know bit about the tech. But more important IMHO is understanding the mental and emotional stresses involved. From not losing your paycheck because you disagree with an unsafe order or the prospect of screwing up and killing a young hand whose parents go to your church. I've seen it all more times then I care to member. And I've jumped out of the rack more then once to the sound of an alarm that wasn't a drill.

And then was that time after working less then 3 years watching them remove a young hand from the drill floor who had been crushed by a joint of falling casing. And then driving the toolpusher and that hand's twin brother to the hospital where his dead brother was taken. And then leaving him alone at the entrance in tears because the pusher needed to get back ASAP to finish runing thd casinv so he didn't piss off the operator by losing even more time.

Obviously that sh*t stays with you. Diagrams just can't do justice to the human nature, good and bad, involved in the process.

[rockdoc123]

Good points Rockman. Most people who have never been on an offshore rig when it all goes south just have no idea, it is frightening but at the same time you can't afford to be frightened (hence the number of damned boat drills). Most people who have never flown in a helicopter more than once think it is an adventure and romantic whereas those of us who at one time or another flew every day for months on end know that 1. you can forget about getting life insurance and 2. gather as many close friends as you can because you will lose several. I lost 4 very close friends over the years from various helicopter incidents. If I never have to get in one again I will be a happy camper.
As to diagrams, I happened to look at the diagram in the BP report that supposedly describes it all. Having spent nearly 40 years living the in the business you would think I could just look at that diagram and say ....yup just the way I had described it from the BP daily updates. But no, one of the more confusing completion/intervention diagrams I've seen. Now if I have a wee problem sorting it out I suspect that the average layman who wouldn't know a casing shoe from a tennis shoe will be considerably confused.
Explaining in words the details of why the relief well was drilled and what it was expected to achieve is far more beneficial to my mind.

[ROCKMAN]

Doc - Decades ago my secretary at Mobil Oil talked the drilling super into an offshore day tour for her and some other gals. She asked for my advice.
I told her: 1) don't walk around the chopper where the tail rotor is. And 2) take a seat at a door even if that makes others climb over you to get inboard. Since I alwats teased her she laughed at that and said "Sure, that way I'll survive if we crash". I told her no: she would be just as dead as the rest on board. But with luck her body might be recovered so her family could bury her. And she laughed again. And then she got to the chopper base and talked with some pilots. Then she didn't laugh anymore. LOL.

So a bit risky choppering out into the. GOM. But not as bad as someone shooting at your ass when going into a hot LZ. LOL. When I first started lot of pilots were VN vets. They would get bored being taxi drivers and would occasionally do some crazy sh*t. So I would always try to empty my bladder before a flight.

[TrueBeliever]

ROCKMAN et. al.

Thanks for your continued posting on this once dead thread! I was one of those following your narrative during the Macondo well blowout on TOD - helped make sense out of the dizzying amount of bullsh*t pushed out by the liberal media.

Just so you didn't think you were writing to yourself and a few friends LOL ...

[ROCKMAN]

pstarr - Not gang up on our buddy TB but often my issues are not with the "liberal media" or Fox News. My constant bitch is with the incompetent/lazy media on both sides of the fence.

From the oil patch review I posted they don't appear to make big tech mistakes. But more important it sounds like it did a good job of highlighting the too often unfortunate mindset of management NOT on the rigs. Thus the somber mood of the hand as he left. And I would bet that mood came from the acceptance that little would have changed even after this event. On a lighter note I'm reminded of a scene from "Patton". As the general drove past a grunt commented: "There goes ole blood and guts. Our blood and his guts". LOL.

An understanding I share with the reviewer. Which is why I probably won't see it. I lived with that mindset for more then 4 decades. As I said earlier I stopped going to funerals and memorials long ago. Difficult enough to deal with it when working let alone doing so voluntarily on days off.

It's nothing unique to the oil patch. You'll hear about similar attitudes from workers in all heavy mechanical industries: time is money...and workers are replaceable. If one can't accept that then they've chosen the wrong career path. Or should try to minimize the risks in a small way by their own actions as much as possible.

[hvacman]

The discussion about occupational hazards made me think of the most dangerous job in my own neck of the woods - literally. Logging. It is the MOST dangerous occupation in the country. 111 deaths/year/100,000 workers. So each year, a logger has a 1-in-a-1000 chance of dying at work.

Here is a link of the most dangerous occupations.

http://time.com/4326676/dangerous-jobs-america/

[ROCKMAN]

Hman - Exactly. And I wonder how many of those accidents are a result of the corporate culture attitude: "If you don't cut faster I'll give your job to someone who will".