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Cameron International Corporation Message Board

  • chopper82sm chopper82sm May 2, 2010 7:19 AM Flag

    Interview with rig survivor

    Sounds like the pressure was more than what the BOP was rated for...

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    • I believe the BOP at use at the time was rated for 15,000 psi. CAM just came out with a 20,000 psi BOP last year.

    • Er... not really. The guy on the interview is saying that they had opened the annular valve on the BOP to cement the top of the well. The unexpected gas kick happened at that point. They would have tested the BOP immidiately before that and never opened the annular valve if the BOP wasn't working right. Here's my amateurish transription of the relative portions of the interview:

      • 3 Replies to morepaveway3s
      • Part 2 of Mark's interview:

        <Segment is 10:48 in length. I'm transcribing portions relative to BOP for length here. but Whole segment is worth a listen if you have time>


        M: the way, why would the government send in a SWAT team. What's that about?

        <note: J initially thinks M is referring to a company SWAT team>

        J: Believe it or not - funny you should mention that becase the... TransOcean maintains a SWAT team - uh, the drilling company - that... they're sole purpose, they're experts in their fields... the BOP - the blowout preventer - uh, they call that subsea equipment - they have thier own SWAT team to send out to the rigs to service and maintain that equipment. They're specialized and highly trained...

        M: <interrupting> Yeah, yeah - but I'm talking about... But what are Interior SWAT teams? What is that?

        J: The Interior - from the government, now - that's - I don't have any idea. That's beyond me. The other gentleman also mentioned the USGS that comes out and does the surveys... I've been on that particular rig for three years, offshore for five years, and I've seen the USGS one time. But what we do have on a regular basis is the MMS, which is the Minearals Management Service.

        M: And they're all under the Interior Department.

        J: OK... <M: Uh, OK> Yes the do have... as a matter of fact, we were commended for our inspection record, uh, from the MMS. We had actaully received an award from them for the highest level of safety and environmental awareness.

        <4:40+ discusson on award, lifeboats, workboat on site taking mud from rig, Coast Guard response, cleanup effort>

        M: ...but to shut down every rig - I mean - in response to this? I mean, I'm not sure why that's...

        J:...that's... there's no... These BOP tests are literally mandated from the Minearals Management Service and they're conducted like clockwork. And I mean, if any one of those tests ever failed, they would immediately stop the operaiton, seal the well up, pull the BOP stack back - back up on the deck, which is - you know, 48 hours minimum - and make the necessary repairs or replacement parts. And then go back down, reconnect, retest, and keep testing until it passes. Or keep repairing it until it passes.

        <conclusion of interview>

      • <3:04, Part 1 of Mark's interview:>

        M: OK, back to James - that's not his real name - Dallas, WBAP, I'm not going to give the working title of what you did their either, James, but I wanted to finish. So, the gentleman was right about the point that obviously the gas got into the... I'll call it the funnel, OK?

        J: Correct. And that's not uncommon, Mark. Um, anytime you're drilling an oil well, there's a constant battle between the mud weight - the drilling fluid that we use to maintain pressure on the wellbore, itself. There's a balance of the well's pushing gas one way and you're pushing mud the other way. So there's a delicate balance that has to be maintained at all times to keep the gas from comming back in, in these - what we call 'kicks' - um, we always get gas back in the mud - um, so the goal of the whole situation is to try to control the kick. You know, not allow the pressure differential between the vessel and the wellbore.

        M: Well - in this case - obviously too much gas got in.

        J: Correct. And this well had... had not a bad history of producing lots of gas. Um, it was touch and go - you know, a few times - but this was not terribly uncommon. Um, you're almost always going to get gas back from a well. We have systems to deal with the gas.

        M: So what may have happend here?

        J: Well, the shear volume and pressure of gas that hit all at once was more than the safety and controls we had in place could handle.

        M: And that's not nec... Is that, I mean - and is that like a mistake on somebody's part - or maybe it's just Mother Nature every now and then kicks up or what?

        J: Mother Nature every now and then kicks up. The pressure we're dealing with out there - you know, drilling deeper and deeper - and, uh, deeper water, deeper volume of the overall depth itself. You know, you're dealing with thirty to forty thousand pounds per square inch range. Uh - You're... serious pressures.

        M: By the way - not to offend you - but we just verified that you are who you are. Which I'm glad that - I'm sure you already knew that. I would like to hold you over to the next hour because I would like to ask you a few more questions about this as well as what happened exactly afer the explosion. During the explosion and after. Can you wait with us?

        J: Sure. I don't know how much of that I can share, but I'll do my best.

        M: All right. Well, I don't want to get you in trouble, but to the extend you can, fine. To the extent you can't, we understand.

        <note: Sad commentary on society when this guy narrowly escapes being incinerated or blown off the rig and he's more worried about lawyers and his employer!>

        <Part 1 concludes at 5:32>

      • Mark Levin (M) interview with caller "James" (J - not his real name) who was on the rig when it exploded

        M: James... Dallas, Texas WBAP... Go right ahead, sir.

        J: Um... Just wanted to clear up a few things with the petroleum engineer... Everything he said was correct. I was actually on the rig when it exploded and was at work. We uh

        M: <interuppting> Whoa - Allright, slow down, whoa whoa whoa, slowdown, hold on - so you were working on this rig when it exploded?

        J: Yes, sir

        M: OK, go ahead

        J: We had set the bottom plug for the inner casing string - which was the production liner for the well - and had set what's called the seal assembly at the top of the well. At that point, the BOP stack he [petroleum engineer earlier in the interview] was talking about - the blowout preventer - was tested. Um, don't know the results of that test, however, it must have passed at that point they elected to displace the risers - the marine risers from the vessel to the sea floor. They displaced all the mud out of the riser preparing to unlatch from the well two days later. So they displace it with seawater. When they concluded the test of the BOP stack and the inner liner - concluded everythin was good...

        M: Wait, let me, let me slow you down. So they do all these tests to make sure the infrastructure could handle what's about to happen, right?

        J: Correct. We're testing the negative pressure and the positive pressure of the well, the casing and the actual marine riser

        M: OK, I'm with you - go ahead.

        J: All right, so after the conclusion of the test, they simply open the BOP stack...

        M: And the test, and the test as best you know was sufficient?

        J: It should have been. Yes, sir. They would never have opened it back up.

        M: OK, next step. Go ahead.

        J: Next step, um... they open the annular - the upper part of the BOP stack...

        M: Which has it's purpose - whoa, whoa. Which... what... Why do you do that?

        J: Um, so you can gain access back to the wellbore.

        M: OK

        J: That's basically a humongous hydraulic valve that is closing off everyting below and above - it's like a gate valve on the seafloor. That's a very simplistic way of explaining a BOP valve.

        M: That's OK - basically it's like a plug. But go ahead...

        J: Correct. Ah, once they open that plug to go ahead and start cementing the top of the well... ah, the well bore... we would cement the top and then basically we would pull off. Another rig would slide over and do the rest of the completion work. When they opened the well is when the gas... the well kicked, and we took a humongous gas bubble kick through the well bore. It literally pushed the sea water all the way up to the crown of the rig, which is about 240 ft. in the air.

        M: Uh, so gas got into it and blew the top off of it. Now, now don't hang up. I want to continue with you because I want to ask you some questions related to this, OK? Including, has this sort of thing ever happened before, and why you think it may have happened, OK?

        J: OK...


    • Also, this sounds like it could be a RIG problem, if there was some electrical box/component that was supposed to be explosion-proof wasn't, or failed. I assume venting gasses are a common occurence when a well is drilled. As such, any source of ignition must be eliminated eg arcing relay contacts, candlelit dinners, etc.

      • 2 Replies to namevacus
      • Apparently you didn't listen closely to the interview. The worker said the the gas enveloped the whole rig. So if we believe his statement, it sounds like it was a tragic accident.

      • I worked in several of the largest gas plants in the world and can assure you that if they have a gas cloud that envelopes the rig, it will find an ignition source.

        If you look at pictures of the rig, before the fire, you will see 5 or 6 stacks that are from internal combustion engines that drive generators. I've seen gas cloud choke off engines, but many times they are the ingnition source.

        You cannot have the total rig be intrinsically safe when you have to produce power and have living quarters. Normally gas kickbacks are diverted to a flare system that is far from the rig deck.

        I have problems with the BOP not operating. This should not be overpowered since they use hydrolics to the close the valve and pressure from the wellhead if it exceeds the hydrolic pressure.

        For some reason, the BOP has not been actuated. I think Cameron has a problem here.

    • Very interesting, thx for sharing.

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