History of Oil

         Crude Oil: Key Historical Events

          Fundamentals of Oil
               Finding Oil & Gas
               Securing Leases
               Drilling For Oil & Gas
               Evaluating/Well Logging/Coring
               Completing the Well
               Cementing/Perforating
               Acidizing/Fracturing
               Artificial Lifts/Injection Wells
               Oil Production/Secondary Recovery
               Waterflooding in the Illinois Basin
               Operation/Sale of Oil

          Why Participate in Oil

          Choose Your Participation Level

          Tax Advantages

          Risks

Drilling For Oil & Gas

Once an area has been selected and the right to drill thereon has been obtained, actual drilling may begin. The most common method of drilling in use today is rotary drilling. Rotary drilling operates on the principle of boring a hole by continuous turning of a bit. The bit is the most important tool. The rest of the rig ( a derrick and attendant machinery) is designed to make it effective. While bits vary in design and purpose, one common type consists of a housing and three interlocking movable wheels with sharp teeth, looking something like a cluster of gears. The bit, which is hollow and very heavy, is attached to the drill stem, composed of hollow lengths of pipe leading to the surface.

Drilling Image 1As the hole gets deeper, more lengths of pipe can be added at the top. Almost as important as the bit is the drilling fluid. Although known in the industry as mud, it is actually a prepared chemical compound. The drilling mud is circulated continuously down the drill pipe, through the bit, into the hole and upwards between the hole and the pipe to a surface pit, where it is purified and recycled. The flow of mud removes the cuttings from the hole without removal of the bit, lubricates and cools the bit in the hole, and prevents
a blow out which could result if the bit punctured a high pressure formation.

The cuttings, which are carried up by the drilling mud, are usually continuously tested by the petroleum geologist in order to determine the presence of oil.

Drilling Image 2Drilling to Total Depth
The final part of the hole is what the operating company hopes will be the production hole. But before long, the formation of interest (the pay zone, the oil sand, or the formation that is supposed to contain hydrocarbons) is penetrated by the hole. It is now time for a big decision. The question is, "Does this well contain enough oil or gas to make it worthwhile to run the final production string of casing and complete the well?"


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