This was shared with me and I thought it was worth posting on here to see what other think of this idea of what might have caused the explosion.
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It seems like just another potential issue in a long list of issues, but not really anything profound. Complications from hydrates were not an unknown at that time. Suggesting a plug delayed the detection of gas buildup does not negate the fact that had the well been properly drilled, cased, cemented, plugged, tested, and circulated out, that gas likely wouldnât have been present in the first place.
It is well established that, at the time, they were circulating out mud for sea water with the mud being discharged directly to the supply boat. If they hadnât cut time by skipping the trip tank or pits and monitoring bbl in/bbl out they would have easily known if there was a hydrate plug because the pit volume would have stopped increasing and the flow-show would have indicated no flow.
So I wouldnât say âcaused the explosionâ so much as may have possibly been another link the long error chain.
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From my reading of the article adding another link in the chain is correct as is no change in the basic cause. However Iâd say another way of looking at it is the hydrate plug added another layer between what was actually happening and what the drilling crew was able to observe.
Earlier reports showed that the drilling crew had a clear indication for 20 minutes that there was a problem before the explosion, this report is saying that was not the case.
Er, at the risk of self-promotion, read our book. We studied that incident for five years and subjected our work to extensive peer review. And it has stood the test of time since publication (see the latest reader review on Amazon).
Hydrates are unlikely. He was also working off incorrect descriptions of the piping on the boat.
Cheers,
Earl
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Read the book. Case closed. They werenât drilling an experimental well using new methods or exploring new matters of geological physics. They took short cuts that did not work out as planned. They had all gotten away with similar acts in the past but this one came back to bite them. Will it change things? Absolutely already has, they donât exchange emails about these shortcuts any more. They go âoff lineâ and make phone calls. Lesson learned.
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Yeah, somewhere in the gigabytes of data I have is a âlessons learnedâ briefing from a law firm. One of the lessons is âemail discipline.â
Earl
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Well hydrates are a thing but they are not a new thing nor in anyway a cause of the Macondo blowout it seems to me.
Read this article several times and cant grasp its purpose. It reads like a public relations release not a summary of a scientific or engineering paper. How dramatic. âWhen I read this in the investigation report, I blamed myself for not having done more than I did". So it wasnât what he first thought it was (mud gas separator) so âsomething else must have caused this accidentâ.
The explanations in Earlâs book are so through and information so well sequenced and cross referenced why come out of left field with this theory missing so many details. What âsystem was plugged with hydratesâ, where was it that âthere was no way for the crew to know exactly what was going on until right before it happenedâ. Drama, no details.
Hydrates can and have been involved in well control incidents. Hereâs a write from a blog post in 2010 during discussion of the Macondo incident.
I am finally glad to see that someone is finally focusing on hydrates as the probable cause of the well control situation, blowout and BOP erratic behavior on the Deepwatyer Horizon. Although I suspected this over 6 weeks ago, based on my experience of almost 25 years ago, I have been out of the oilfield for over 20 years and much better minds than mine have been investigating this situation. In Sept 1985 I was rig manager for the drillship Sedco 472, drilling for EXXON on the Bluethroat prospect well OCS-G-7956 #2 on Mississippi Canyon Block 755 in 3,100â of water. I believe we were under the 11 3/4 " liner shoe, I think we had just re entered the well after a hurricane move off, took a kick, shut in, vented a lot of gas out of C/K lines. BOP"s functioning very erratically. Were closed in on annular, erratic PSI readings in C/K lines, ie. we werenât sure if valves open or closed, same with rams, and even upper annular, signal indications good for function, but taking insufficient hydraulic volumes to confirm open or close status on valves or rams. Ran 2 '7/8" tubing inside the riser alongside the DP. took weight at 300" above upper annular, started circing , got gas in returns, diverted, ran in tubing slowly, circing up gas to top of upper annular, Exxon decided we were probably hydrated, we went inside DP with w/line, ran CBL, no cement in liner annulus. cemented in bottom of DP, perfed casing the through DP, squeezed cmt into annulus. For the next few weeks we circulated heated mud, ran coil tubing with steam, a variety methods to get the gas out of the bore. Itâs been a while, but I recall we pretty much confirmed we had been hydrated, our rams and valves essentially ice blocked, and I believe we determined the 13 3/8" hanger seal (last full string of casing in the hole) had leaked, possibly due to hydrate issues. Anyway, Exxon pretty much confirmed that hydrates had caused our well control issues. It snuck up on us because the hydrates (crystallized methane) did not behave as gas in their crystallized form and we did not have conventionl pressure/volume increase indications of gas in the well bore. I just happened to be on the rig the day it blew, on a rig visit, and although I donât recall the exact details, we may have just reconnected and reentered the well after one of the 4 hurricanes we moved off for that season, I remember clearly that we were in a section of hole we felt safe and had no indications or reason to expect we had gas in the bore, were very surprised when it unexpectedly blew out on us. Thankfully, Exxon was very conservative and we probed the well with the tubing, heated mud, wireline survey, cement squeeze job until we eventually got the well back under control. Fascinating, I dug up my pipe tally book for the 10 days or so I was on the rig for the initial evaluation of the problem and remedial steps taken along with the erratic PSI readings, even the hydraulic volumes recorded when we functioned BOP rams, showing the reduced hyd volumes to open and close functions which essentially indicated to us something was keeping our valves and rams from fully opening and/or closing. Re Reading my detailed hourly notes after 25 years was both fascinating and eery. When we got the well secured, we pulled the BOPS, while pulling them, the last chunks of ice blew out the riser C/K lines. At surface, the BOPâs functioned normally with out need of repair. We went back in the well, and eventually took it to TD with a 7" liner to 12,163" by the next March of â86. 4 hurricane evactuations, a somewhat preventable drive off , this 3-4 week well control operation, it was a heck of a well. Despite the fact we had to move off location for 4 hurricanes, Danny, Elena, Juan and Kilo, we were very fortunate as 2 came before and 2 after the well situation, not sure what would have happened if one came along while we were connected trying to get the well under control. Anyway, Iâve been out of the oilfield for over 20 years, but when this came up brought back the thought that we thought we were in a safe condition, the hydrates masked the danger we were in, perhaps those very experienced Transocean hands were lulled in by the fact they had functions blocked and thought that indicated well was static. When they reported the negative test that showed DP pressure, and 0 on the Kill line, I would guess the kill line was blocked by hydrates. With the well control issues they had on that well, doesnât make sense they didnât run the CBL or at least set the surface plug, almost certainly when they started displacing and dropped hydrostatic the methane reverted to gas phase, and it doesnât take much gas expanding from 5,000â to evacuate the riser in a hurry. Ramon Gomez and John Barker were the Exxon engineers on that well in 1985, they wrote a book that chronicled this SEDCO 472 event as well as others that involved gas hydrates in deepwater drilling.
If you find there is any merit to my observations, or interested in the hour to hour log of what we and Exxon did for the first 10 days or so of our well control situation in 1985, please contact me, there are very few oilfield people here in Maryland, no one to really discuss this with, and Iâve been telling anyone who will listen for the past 6 weeks about hydrates, even the oilfield people I keep in touch with discount hydrates. If I had not observed the effect of hydrates myself, I probably wouldnât listen either. I would be interested to know if my observation has any validity.
Elsewhere he has described it as:
Coming back from a hurricane evacuation we reentered the well and were drilling out a EZSV when we got a gas influx. Extremely erratic BOP C/K line operation, couldnât pump down the C/K lines with indications the valves were open. Shut in the well on annulat, VBRâs wouldnât close, gas blew out in riser, couldnât pump down C/K to fill the riser, got very hairy, finally able to fill riser from top but a close call. Tooks us weeks to sort out the situation and get well back under control. There are several references to this well situation, especially Barker and Gomez book on hydrates in deepwater drilling operations who were the Exxon Engineers on the well. Sounds like this could be exactly what happened on the Deepwwater Horizon. the presence of the gas hydrates (crystallized methane) probably masked the presence of gas in the wellbore until it was too late. I dug up my notes from that time frame, we took the kick at mid day on 12 Sept 1985. When I read my notes that we woke up all hhands at 3:00 Pm for possible evacuation because of gas blowing out the riser, hit a bit close to home. didnât think about this until Deepwater Horizon incident and I recalled our experience on the 472 almosty 25 years ago. Would have thought hydrates was a much more known phenomena now.
These posts by this gentleman are no longer on line that I can find but there are others which repeat this story that date to May of 2010.
I think this guy was doing what everbody was then, searching for a reason or cause for the unthinkable.
If you follow the trail of Barker and Gomez it leads to a paper here where you can see from the abstract and excerpt that these guys were documenting the hydrate problems in deep water drilling in the mid to late 80âs.
So yes hydrates can get in the way of well control but the cases above both happened after leaving the well (one round tripped the BOP for service and the other for storm) and coming back perhaps allowing gas to accumulate and escape at the top, close by the cold water and result in the blockages described. But Macondo was actively being worked and until they decided to so unwisely displace there was probably gas in the well but not moving yet. Who knows what was going on down there.
Thatâs the whole point, there is a whole book of explanations and causes that will have much wider positive affect on deep water drilling safety - if there still is a deep water drilling industry in a few years - and if management has been willing to take the lessons onboard. You donât have to go looking for a novel silver bullet of a cause.
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What he said.
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Experienced 2 of the four hurricanes mentioned in the well stated article. Juan was not the strongest, but most unpredictable. Came in, came out, and looped. Circled for days below it to avoid it, still tagged my ass after it made landfall and came back out into the Gulf.