For how long do oil wells produce oil?

I suspect it's a very variable answer, depending on how much oil is in the particular deposit, and what composition the oil is.

I have no idea how long this particular spill (the gulf oil disaster) would continue if left untouched. The BP geologists might have some idea.

Ros is correct. Depending on the permeability, pressure, the amount of free water and salt water and fracturing of the production Formations, some oil wells can preoduce for half a century or more. The "Indiana" and "Oil Creek " wells of the "colonel Drake" days (1859) are still producing as "stripper wells" A stripper well is a seepage hole that collects about 10 barrels a day or less. In NW Pa , there are still a bunch of plastics and paraffin using industries (several companies that produce scented candles Etc).
Mom and Pop oil field stripper wells and some pumping wells are still all over the NW PA area and some of them are pumping oil from wells that are almost 100 years old.
In other areas, like The Wst Texas or Kern County Cal oil fields we have wells that only produce for a few years to some that are over 50 years and going.
When a well stops peak production, we can go back in and mess with the rock (making lotsa cracks so that oil can flow freely) we also can outfit the wells with gas (CO2 spargers, and hot water fluid extraction seystems to do wjhat we call "secondary recovery". WE can also go in and snake wells sideways around an old field and suck up the residual crude like sucking up the last bit of a milkshake.

Ya gotta look almost at every well's production records separately

I think this BP well may be producing faster than it would normally produce.

The answer was easily available on a simple search with the question, "How long does an oil well last". The big oil companies did have data available on the Internet. !st the majority of oil wells produce 10 barrels of oil or less per day. 2nd according to data, without fracking or other means of increasing production, the average oil well produces about 10 years. This is the primary oil pumping production. Fracking, nitrogen injection, and other means can extend production to about 20 to 25 years on average. Also, the comment, "I tried to ask the big oil companies, but they either ignored or insulted me", was an inaccurate statement and you don't know how to do research.

Im thinking that easyasabc has moved on to another job. Maybe he or she is a principal since its been 10 years since the question was asked.