Releif Wells - Why 2 miles deep, why not 200ft

[Tidybuoy]

Another question about the gult oil spill and the proposed solution.

Today I read that the releif well being drilled is like hitting a dinner plate two miles below the surface of the earth.

I'm wondering why are the relief wells scheduled to intersect with the main well at 2 miles below the surface? Why don't they just change the angle and intersect, say 100 ft below the surface. Obviously the engineers must know what they are doing and have their reasons but I don't seem to understand.

Any Insight on this?

Next Question: Looking at the blowout preventor (diagrams), it appears that the mile long pipe fell to the sea floor and bent just above the BOP. Now, they are slicing away at the 21" diameter pipe to clear excess debris pipe from around the BOP and will next cut a nice clean cut above the BOP.

These diagrams show me that the pipe bent vs snapped off the BOP and anywon who has ever used a garden hose knows that if you need to stop the water fast, just bend.kink the hose. Why haven't they used the giant claw machines to crimp the pipe in several spots, at least to slow down the flow?

Just wondering...

[oldE]

I'm not an engineer, but my best guess for the reason behind the deep interception of the borehole would be to avoid the risk of the diverted pressures blowing out around the blockage. In effect they would be using the thousands of tons of material in those two miles of earth to stabilize things.

In a similar fashion, suddenly crimping an already stressed pipe to block the flow could cause a rupture when the moving mass of material has nowhere to go.

Keep your fingers crossed.
Les

[s_wilwerding]

You can't crimp the pipe - the pipe is designed to take the pressure in a cylinder, not at a tight crimp. If you crimped it, the pressure would almost immediately blow out the crimp.

[Pazuzu]

Originally Posted by Tidybuoy

I'm wondering why are the relief wells scheduled to intersect with the main well at 2 miles below the surface? Why don't they just change the angle and intersect, say 100 ft below the surface. Obviously the engineers must know what they are doing and have their reasons but I don't seem to understand.

They need that vertical column of 12,000 ft to give the kill mud enough weight to press down on the oil. They're not going to pressurize the mud in, it's the weight itself that squeezes the oil and gas back into the formation.

Also, if the relief wells are close to the oil and gas, then it's much cheaper to convert them to production wells in a year

These diagrams show me that the pipe bent vs snapped off the BOP and anywon who has ever used a garden hose knows that if you need to stop the water fast, just bend.kink the hose. Why haven't they used the giant claw machines to crimp the pipe in several spots, at least to slow down the flow?

Just wondering...

The pipe did kink, but it's nearly cracked all the way through. It's a heavy wall pipe, not designed to bend at all. Once it did bend, it cracked from the stress, and exposed non-treated metal inside the wall. that is quickly corroding and disintegrating. as well, when they did the "top kill" the whole thing got pressurized, and they blew several new holes open in it. If they took the claw and crimped it, it would crack completely open.

They've given up on "stopping the flow". They've stated that the flow won't stop until the relief wells hit, until then they're going to recover as much oil as possible (snicker...).

[RWebb]

well, we went from "too big to fail" to "too deep to drill" (safely)...

[WolfeMacleod]

Don't know if any of you have seen this, but here's a live underwateer camera of the operations..
Live Video - CBS News Video