[Domangart]

Dr Bill KGO radio. The well head is about 3,300lbs but if you attempt to close it then the pressure will increase to 175,000 lbs I recall the diving math was something like 33ft=14.1lbs times 5000 feet and the drill is at 18,000 feet plus the earth pressure at that level

[Ernest_at_the_Beach]

I don't understand how he would arrive at that pressure...I'll see if I can fine the thread at the Oil Drum where they talk about the pressures in the well at various points ...all less than 20,000.

There is a deep NG well in the Anadarko basin in Western Oklahoma where the down hole pressure is close to 30,000 psi.

Guess it is pressure at the BOP:

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[proud_yank]

The well head is about 3,300lbs but if you attempt to close it then the pressure will increase to 175,000 lbs I recall the diving math was something like 33ft=14.1lbs times 5000 feet and the drill is at 18,000 feet plus the earth pressure at that level

There are two different pressures to consider- wellhead pressure and hydrostatic pressure (pressure of water at depth x). You can't use the well depth to determine the hydrostatic pressure.

IIRC, the wellhead pressure did not exceed 15,000psi. The 3300# you mentioned may be the hydrostatic pressure of the ocean. When I calculated it I got 2170psi for 1515m (5000ft) depth, assuming the density of seawater= 1000kg/m3.

Don't know what would create 175,000#, that is incredibly high.

[jimt]

Dr Bill KGO radio.

Dr. Bill needs to look for better sources.

Well logging instruments are designed to take any expected pressure from surface to touch down at the bottom of the hole.

Most are designed to 20,000 psi. Newer models when I worked at a logging service provider were designed to 25,000 psi. We tested some parts to 30,000 psi, but those were parts of measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools.

30,000 is nothing to sneeze at, but certainly not impossible to work with. I designed and built a pressure test chamber for that pressure, and proof tested it at 45,000 psi. The top screwed on (and unscrewed) by hand and it was sealed with a single o-ring.

Modern waterjet cutting systems run at 50,000 psi or higher. Parts are commercially made that are rated at 60,000 psi (see Autoclave Engineers).

The wellhead pressure, shut off, is nowhere near 175,000 psi. If you had a valve on the pipe and slammed it shut in milliseconds, you would get a hellacious pressure surge. But the equipment we're discussing doesn't move that fast. Dr. Bill is wrong.