When drilling oil wells, one of the key concerns is bringing the oil to the surface for extraction. The natural pressure of the subsurface reservoir surrounding the oil well is typically high enough to push the oil or gas all the way to surface. However, this is not always the case, especially in depleted fields where the pressures have been lowered by other producing oil wells. Installing a smaller diameter tubing may be enough to help the production, but other types of artificial lift can also be used. Common solutions in oil well drilling are downhole pumps, gas lift, or surface pumpjacks - the "nodding donkey" pumps dotting the countryside in old oil fields in Texas and Oklahoma.
If you are interesting in learning about the process or business of drilling oil wells, search on Oil Well Drilling in Cottage_Hills using the MagicYellow.com directory.