O.T. Crude Oil Flow

I have an off-topic question I am posting only because of the depth of
knowledge (campbell and his assorted sock puppets aside) found on this
group is nothing short of amazing. That said, here goes.

Say, for example, I wanted to cut into an active, three foot diameter,
600 PSI light sweet crude pipeline and place a valve on it through
which I could siphon roughly 1000 metric tons in the space of three
hours.

How large a hole would I have to drill?

Don't laugh. I know that it's nearly (if not utterly) impossible to
do, especially considering the fact that the author of the article in
a rather well-known general interest publication claimed it was being
done, underwater, in a sealed "home made" caisson with alarming
regularity by militants using, at best, primitive tools.

Thoughts?

al staats