Introduction of oil casing in industry

Casing is oil, gas well cementing special steel pipe, used to seal oil, gas, water layer; protection of the wall; to prevent blowout or wall collapse. According to the use, casing is divided into surface casing, technical casing and casing casing. When drilling began, after drilling the upper surface of the soil layer, because these strata, after all, soft, easy to collapse, in order to prevent blowout and ensure smooth drilling, need to enter a layer of casing. Surface casing, such as the depth of the next, with the situation there are hundreds of instant noodles to the individual, up to more than a thousand meters, but most wells do not exceed 200 meters. In the bottom of a more solid and oil, gas, water pressure is sure, drilling cycle is short, you can not under the surface casing.
After the casing casing into the ground, in the continued drilling, but also encountered a variety of complex situations, such as well leakage, well collapse, high pressure oil, gas, water, etc., when the use of mud and other measures, if still In the case of ineffective areas, it is necessary to drill down the complex formation, such as the technical casing, to isolate difficult to control the complex formation, to ensure the smooth progress of the drilling work in the formation is not too complicated Drilling depth is not the case, Generally can not under the technical casing; but for the exploration wells should have spare technology casing.