What is roles of Pipes when drilling rigs ?

Answer 1

There are two kinds of pipes involved. One is the casing for the hole that keeps soft stuff from caving and leaking into the hole, not always needed in hard rock. The other kind is the drill string. These are lengths of pipe which are threaded on the ends and during drilling you see them standing upright in sections in the derrick. In order to drill the hole, a rock bit is put on the end of a pipe and both are lowered into the hole so far. The pipe is clamped near the top and another length of pipe screwed on and the string lowered some more and repeat adding pipe. When the bit reaches the bottom, the wedge plate at the top is rotated by heavy machinery on the surface, which turns the pipe, which turns the bit and carves out rock. "Mud" is pumped down the middle of the pipe to lube the process and carry rock dust to the surface. Every time the bit gets dull or needs changing because of different rock (checked by looking at the uprising mud), the whole string of pipe is lifted until one piece is up in the derrick, the rest is clamped and the top unthreaded and set aside, then the string is raised and the process is repeated. If drilling is 6,000 feet down (shallow these days), then it takes 200 30 foot pipe lengths to get down. Tall derricks can take off 2 or 3 or 4 lengths together.
http://en.wikipedia.org/wiki/Oil_well

Answer 2

Casing maintains the integritiy of the hole while drilling, provides a conduit for mud when fracking and flowing, and a conduit for oil flow during production. Runs in and out of the hole are called a "trip". A "twist off" is when the casing shears during drilling which requires "fishing" to retrieve the joint(s) of pipe still down hole.

Answer 3

Core samples? or a conduit to the oil/water