The Cellar - Gulf coast oil spill

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- - Gulf coast oil spill (http://cellar.org/showthread.php?t=22643)

Quote:

Originally Posted by Griff (Post 658791)

I wonder what "heavy mud" is?

Quote:

Drilling mud is usually a clay and water mixture. A common drilling mud is made of bentonite clay and is called gel. A heavier drilling mud can be made by adding barite (BaSO,). Various chemicals are also used in different situations. The drilling mud liquid is usually water (freshwater based or salt-water-based) but is sometimes oil-based. Drilling muds are described by their weight. Water weighs 8.3 pounds per gallon. Average bentonite drilling mud weighs from 9 to 10 pounds per gallon. Heavy drilling mud weighs from 15 to 20 pounds per gallon. The heavier the drilling mud, the greater the pressure it exerts on the bottom of the well.

Circulating drilling mud serves several purposes. The mud removes cuttings from the bottom of the well. As the mud flows across the bit, it cleans cuttings from the teeth. The drilling mud cools the bit from heat generated by the friction of drilling. In very soft sediments, such as in a coastal plain, the jetting action of the drilling mud squirting out of the bit on the bottom of the well helps cut the well. The drilling mud also controls pressures in the well and prevents blowouts. At the bottom of the well, there are two fluid pressures. Pressure on fluids in the rock tries to cause the fluids to flow into the well. Pressure exerted by the weight of the drilling mud tries to force the drilling mud into the surrounding rocks. If the pressure on the fluid in the subsurface rock is greater than the pressure of the drilling mud, the water, gas, or oil will flow out of the rock into the well. This often causes the sides of the well to cave or stuff in, trapping the equipment. In extreme cases, it causes a blowout. In order to control subsurface fluid pressure, the weight of the drilling mud is adjusted to exert a greater pressure on the bottom of the well. This is called overbalance, and the drilling mud is then forced into the surrounding rocks. The rocks act as a filter, and the solid mud particles cake to the sides of the well as the fluids enter the rock. This filter or mud cake is very hard. Once the filter cake has formed, the sides of the well are stabilized and subsurface fluids cannot enter the well.

From here. Interesting stuff!

The heavy mud seems to be working for now. At this point as much as 29.5 million gallons of oil may have been spewed out. There are concerns with the hurricane season approaching that oil slicked waves could slosh inland creating even more damage.

I heard on NPR this morning that the plants in the wetlands may all be killed off. This would be a terrible blow for those ecosystems. Never mind all the animals that depend on them, the roots of the plants help hold the soil in place. Dead roots mean all the soil will be all washed out to sea, leaving empty waste lands behind. :(

what about the important things - like bourbon street?

It is interesting that petroleum is generally measured in barrels. Yet this spill is being invariably publicized in US news outlets in gallons. 42 gallons to the barrel. Is someone trying to make it sound bigger or something?

Sam, delta mud would be immediately replaced if washed out to sea. What's making the Mississippi Delta again?

And in due -- geologic -- course, the Mississippi River delta deposits will themselves become source rock for petroleum and natural gas.

Hey, report it in liters and really be amazed! ;)

I believe that the reason the top kill wasn't attempted sooner is that it takes a while to put the equipment onto place, and there were quicker (but less likely to work) things to try first. As it is, top kills have a 60-70% chance of success on dry land. They've never been done under a mile of ocean before. I wonder if the water pressure might actually help keep the oil in the well

I don't see how people can blame Obama. It is BP's (and/or the other two corps involved) fault that it blew, and BP's job to plug it and clean up. All the prez can do is tell them to "plug the leak" which they were attempting already. He could order in Coast guard or National guard resources to help with containment and clean up, but I've seen some of that on TV already.

Really, what was Obama supposed to do that he hasn't?

Just shy of 159 liters/bbl. Quickie from Wiki, scroll down to Oil Barrel. Says the SI world uses cubic meters or else tonnes. Works for me.

Quote:

Originally Posted by Urbane Guerrilla (Post 658941)

Sam, delta mud would be immediately replaced if washed out to sea. What's making the Mississippi Delta again?

No, they were not talking about delta mud. They were referring to the soil substrate that forms the basis for life in the wet lands. If this substrate is washed out to sea, it will not be replaced for a long, long time. Plants will no longer be able to take root and grow in former wetlands areas. The entire ecosystem will be subject to collapse.

Quote:

Originally Posted by Urbane Guerrilla (Post 658941)

Never once have I heard the spill described in gallons. This spill is not a media invention, it is a crime.

I've seen it as both gallons and barrels, but mostly barrels. I'm annoyed at the few news stories that have reported gallons. Keep your units consistent, people.

I have seen both as well
Watched a lot of CNN this am - in some reports, amounts were gallons.
Made it rather confusing.

The top kill has been declared to have failed. Bugger.
I think we're up to plan H now (notably similar to preparation H) which is a sea floor riser containment thing. I don't know how that differs from the top hat thing was tried earlier.
The relief well is the only reliable solution. That is still a long way off. I kind of wonder if all the other attempts are expected to fail but are being done to maintain the appearance of doing something.

I've been wondering the same thing. All this is window dressing till the only viable solution is completed.
I really don't understand why they can put a smaller tube inside, yet cannot put a larger pipe over it.

Guessing at the physics here. A small pipe inserted inside the main pipe with a tight seal would maintain the pressure, allowing extraction. A big containment dome allows the spill to burst from the pipe. The spill is part natural gas. As the gas gets released from the pipe, it undergoes pressure drop, thus expanding and cooling substantially. This cooling causes some hydrocarbons in the spill to freeze. These frozen bits clog up the containment dome, so additional oil or gas is forced out into the open sea again. I think that was what went wrong with the Top Hat and similar strategies.

Wasn't the top hat a funnel shape though? Does that matter?

Was ZenGum's post full of innuendo, or is that just me?