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Well completion is the process of making a well ready for production (or injection) after drilling operations. This principally involves preparing the bottom of the hole to the required specifications, running in the production tubing and its associated down hole tools as well as perforating and stimulating as required.
Different methods of measuring the drill pipe length also have a significant effect on the accuracy of the measurement made. Pipe "strapping" is commonly used to define drill pipe length, where the pipe is measured on the pipe racks using a (steel) measure tape. These results are noted in a tally book, and the drillstring length is hence defined.
Deeper strings usually are not cemented all the way to the surface, so the weight of the pipe must be partially supported by a casing hanger in the wellhead. Casing that is cemented in place aids the drilling process in several ways: [2] Prevents contamination of fresh water well zones.
Drill pipe is most often considered premium class, which is 80% remaining body wall (RBW). After inspection determines that the RBW is below 80%, the pipe is considered to be Class 2 or "yellow band" pipe. Eventually the drill pipe will be graded as scrap and marked with a red band. Drill pipe is a portion of the overall drill string.
Drilled wells are usually cased with a factory-made pipe composed of steel or plastic. Drilled wells can access water at much greater depths than dug wells. Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location, and deep or confined wells, sunk through an impermeable stratum ...
[2] In ancient China, deep well drilling machines were in the forefront of brine well production by the 1st century BC. The ancient Chinese developed advanced sinking wells and were the first civilization to use a well-drilling machine and to use bamboo well casings to keep the holes open. [3] [4]
The production liner has the same function as a complete string of production casing. A typical casing arrangement in a well is shown in the diagram below. In this case, the surface casing is set to a depth of about 3,000 ft (910 m). Two intermediate strings are set in this well — a 13 + 3 ⁄ 8 in (340 mm) string and a 9 + 7 ⁄ 8 in (250 mm ...
A steel pipe (casing) is placed in the hole, to provide structural integrity to the newly drilled well bore. Holes are then made in the base of the well to enable oil to pass into the bore. Finally, a collection of valves called a "Christmas tree" is fitted to the top; the valves regulate pressures and control flow. The drilling process comes ...