Well Casing

Well Casing

Installing the well casing is a vital a part of the drilling and completion method. Well casing consists of a series of metal tubes put in within the freshly trained hole. Casing serves to strengthen the perimeters of the well hole, make sure that no oil or fossil fuel seeps out because it is dropped at the surface, and keep different fluids or gases from oozy into the formation through the well. The designing is important to confirm that the correct casing for every well is put in. Types of casing used rely on underground characteristics of the well, as well as the diameter of the well that again depends on the dimensions of the drilling bit used and also the pressures and temperatures fully fledged. In most wells, the diameter of the well hole decreases the deeper it's trained, resulting in a cone like shape that has to be taken under consideration once putting in casing.

There are 5 differing types of well casing. Conductor casing is a method in which casing is done before the actual drilling to prevent from caving in and to assist in bringing the lubricator up from the lowest of the well. • Surface casing is that the next sort of casing to be put in. It is anyplace from a hundred to four hundred meters long, and is smaller in diameter to suit within the conductor casing. Its primary purpose is to shield H2O deposits close to the surface of the well from contamination by leaky hydrocarbons or salt water from deeper underground. It additionally is a passage for lubricator returning to the surface and helps defend the excavation from harm throughout drilling. • Intermediate casing is sometimes the longest section of casing found during a well. Its primary purpose is to reduce the hazards related to underground formations that will have an effect on the well. These embrace abnormal underground pressure zones, underground shales and formations which may otherwise contaminate the well, like underground salt water deposits. Liner strings are generally used rather than intermediate casing. Liner strings are sometimes simply hooked up to the previous casing with “hangers” rather than being cemented into place, and area unit therefore less permanent. Production casing, as an alternative known as the “oil string” or '”long string,” is put in last and is that the deepest section of casing during a well. This casing gives a passage from the surface of the well to the petroleum-producing formation. the dimensions of the assembly casing depends on variety of concerns, as well as the lifting instrumentality to be used, the amount of completions needed, and also the risk of deepening the well at a later date. for instance, if it's expected that the well are going to be concentrated later, then the assembly casing should be wide enough to permit the passage of a drilling bit shortly. it's additionally instrumental in preventing blow-outs, permitting the formation to be “sealed” from the highest ought to dangerous pressure levels be reached. Once the casing is put in, conduit is inserted within the casing, from the gap well at the highest to the formation at the lowest. The hydrocarbons that area unit extracted run up this conduit to the surface. The assembly casing is often five to twenty-eight cm (2 -11 in) with most production wells being half-dozen inches or additional. Production depends on reservoir, bore, pressure, etc., and will be but a hundred barrels per day to many thousand barrels per day. A packer is employed between casing and conduit at the lowest of the well. oil and gas courses in kerala