Oil casing pipes are steel pipes used to support the sidewalls of oil and gas wells to ensure the normal operation of the whole well during the drilling process and after completion. The number of layers adopted of each well depends on the drilling depth and geological condition. Cement should be used for well cementation after the casing pipe is put into the well. Differing from oil tubes and drill pipes, they can not be reused and belong to disposable consumption materials. Therefore, the consumption of casing pipes accounts for more than 70% of all oil well pipes. The casing pipes can be divided into three types according to the service conditions: duct, surface casing, intermediate casing and oil-string casing.
Oil casing pipe is an important equipment for oil drilling. Including the drill pipe, core barrel and casing pipe, drill collar and steel pipe for small diameter drilling.
Oil casing pipes are used for oil well drilling.
Oil casing head housing can be divided into short thread casing with its coupling and long thread casing with its coupling.
(1) According to the regulations, the length of casing head housing made in China varies from 8 to 13 meters. The casing pipes that are not less than 6 meters can be provided but the quantity shall not exceed 20%.
(2) The casing head housing shall be free of folds, hairlines, separation layers, cracks, rolling folds and scabs inside and outside. These defects shall be completely removed and the removal depth shall not exceed 12.5% of the nominal wall thickness.
(3) The outer surface of the coupling shall be free of folds, hairlines, separation layers, cracks, rolling folds, scabs and other defects.
(4) The thread surface of the casing pipe and the coupling shall be smooth and free of burrs, tear and other defects that may cause thread interruption and affect the strength and connection tightness.