N80 oil casing is an important equipment for oil drilling. Its main equipment includes drill pipe, core pipe and casing, drill collar and small diameter drilling pipe. Domestic casing is made of hot-rolled or cold-drawn steel for geological drilling. Steel grade is expressed by “DIZHI”(DZ). The commonly used casing grade is DZ40 DZ55 DZ753.
N80 oil casing is mainly used to support the wall of the well during drilling and after completion to ensure the normal operation of the whole well.
According to SY/T6194-96 “Petroleum Casing”, the types and packages of oil casing can be divided into short threaded casing, its coupling and long threaded casing and its coupling. According to SY/T6194-96 regulations, domestic casing should be tied with steel wire or steel strip. Each casing and the exposed part of the coupling thread should be screwed up to protect the thread.
The inside and outside surfaces of the casing should not be folded, striped, separated, cracked, rolled and scarred. These defects should be completely removed and the removal depth should not exceed 12.5% of nominal wall thickness.
Calculation formula of oil casing is
(external diameter-wall thickness)* wall thickness *0.02466=kg/m (weight per meter)