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USUFB and others in the "awl bidnezz" -- bad mistake pics

samzheresamzhere BannedPosts: 10,923 Senior Member
USUFB in the Thanksgiving plans thread talked about his work on the drilling rig (onshore) and mentioned how a drill motor dropped onto the rig platform, which could have easily been fatal.

I don't have pics of one of these incidents, but US, some our monitoring equipment was onboard a drillship and although our stuff was not involved I did get the info on the story. A drillship is an ordinary looking cargo-style ship with a big drilling rig stuck right into the middle of the ship. What happens of course is that the ship travels to the desired spot and then anchors or moors, and then they drill right down thru the center of the opening in the middle of the ship. And no, it doesn't leak.

Well, as the drilling proceeds, the drill pipe is heavy steel. It's standard-looking pipe about 8" diameter, each section maybe 12 feet, and threaded. As the drilling proceeds, new segments of pipe are threaded onto the string. While this happens, the pipe is supported by huge pneumatic clamps, called "tongs" and the rig workers wrestle the tongs around to screw on new sections. All the while, the pipe is also held by large clamps above this. Now if the pipe string becomes many tons heavier and this enormous load is compensated by the ship settling into the water and so on. Well on this one ship, a maintenance foreman stupidly "saved time" by taking off the baffles surrounding some of the gear that needed regular lubrication. Normally you stop drilling, remove the baffles, lube up the stuff, replace the baffles. But he decided it was better to just keep the baffles off and nobody knew this. What happened of course was that the baffles were designed to prevent the oil lube from splashing out onto the drill pipe clamps, and without the baffles, the clamps got coated with oil. And slick, duh. So as the drill rig managers and top crew watched in horror, the drill pipe began to slip down from the clamps. Pressure was increased but the slip continued. Luckily an alarm was sounded and the drillers took cover before the ship "dropped the string" - the whole string cut loose and plunged into the deep. And the springy reaction was to whip up the drill rig tower like a coiled spring, that enormous load suddenly going away, and the tower flipped up into the air and spun down onto the ship's deck. Only a few minor bumps and scrapes to the crew so that was good, but the cost was millions. Plus one fired maintenance supervisor.

Anyway, here's a typical drill rig of the type known as a "jackup":

punch1.jpg

There are 3 vertical support columns (jackup rigs don't float while drilling -- they are used in only a few hundred feet of water), and they sit on 3 big feet. How it works is that the rig is floating and is towed and anchored, then they jack down the feet till they push thru the seafloor mud and crud and find more solid footing. Continuing to push down, the rig starts to lift off the floating position, but as this happens, the feet penetrate more, finding deeper and more solid footing. The rig contains big excess tanks on its side, and these are pumped full of seawater for adding weight. The jacking process is slow and careful, gradually pushing the feet deeper into the seabed and the hull raising above the water, the weight then pushing the feet lower, then jacking higher, and slowly repeating till the fully loaded rig sits about 20ft above the waves. The extra weight added by the ballast tanks full of seawater simulates the drilling activity and weight of a helicopter landing on the rig, and the pressure and vibration of the actual drilling.

In the photo you can see the rig in its drilling position, off one side of the rig, the copter deck on the other side, and the 2 cranes for lifting pipe and other things.

But if the contractor is busting a gut to save money (and time) and doesn't give a damn about safety, he hires unqualified and uncertified supervisors, who then bend all the regulations and sometimes get by with it, sometimes disaster.

Here are the results of what's called a "punchthrough" -- one of the platform feet punches through a layer of silt and collapses maybe 20-30 feet deeper. This can of course totally capsize the rig or in this case, tilt it so much and so fast that the drill rig collapses 180 deg and that creates havoc all over the rig, due to the immense shock wave of the collapse and then the huge weight displacement. The punchthrough was caused by the supervisors accelerating the settling procedure too quickly and not waiting till the rig settled. There are trained people available who do nothing but supervise the lowering procedure, who know all the dynamics and the process. But the rig owners decided they could do it themselves. The rig was leased by a small wildcat firm in the Indian Ocean.

punch2.jpg

Look for example at the rectangular grid that's in the lower left area of the rig. That is the underside of the drill tower. It collapsed and rotated 180 and swung upside down, killing 14 workers in an instant. Many others were injured from the shock wave and the flinging of large metal fragments. And there had been a copter sitting on the pad. It also was flipped into the water and two crew were lost there. The size can be estimated by the big supply ship in the top of the photo and the other ship pumping water onto the ruined rig to dampen the fires that occurred.

Replies

  • Big ChiefBig Chief Senior Member Posts: 32,995 Senior Member
    Didn't they discover the BP spill was because of taking shortcuts on valves/pumps?

    I don't think I would wanna live and work out on them offshore rigs. I know they rotate crews, but not for me. We have a member who was/is a shuttle helicopter pilot and NG pilot. Wonder where he is now?

    I can't even remember his screen name, he used to post all the time on here.
    It's only true if it's on this forum where opinions are facts and facts are opinions
    Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
    I'd rather have my sister work in a whorehouse than own another Taurus!
  • samzheresamzhere Banned Posts: 10,923 Senior Member
    Big Chief wrote: »
    Didn't they discover the BP spill was because of taking shortcuts on valves/pumps?

    Yes. The terrible accident on the BP rig was due to many shortcuts and other violations building up until something went bust.

    I've never worked on a rig or platform but I've been on a jackup just after drydock. Those things are huge. Closest I ever got to the oilfield in actual work was when I spent most of a year at the Gulf refinery in Port Arthur Texas.

    Rig work isn't too dangerous really. Only a small percentage of the crew are ever exposed to hazardous conditions, such as working on the fig floor or monkey bridge (a small cage-like structure near the top of the rig. But yeah, you get a blowout or other disaster, it doesn't matter if your job is mess cook -- you're in trouble.
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