N80 oil casing is an important equipment for oil drilling. Its main equipment also includes drill pipes, core pipes and casings, drill collars and small-diameter steel pipes for drilling. Domestic casing is made of geological drilling steel through hot rolling or cold drawing. The steel number is represented by "geology" (DZ). Commonly used casing steel grades include DZ40, DZ55 and DZ753.
API has three lengths: R-1 is 4.88~7.62m, R-2 is 7.62~10.36m, and R-3 is 10.36m or more.
Some imported goods are marked with LTC, which means filament buckle sleeve.
Purpose: Mainly used for oil well drilling, mainly used to support the well wall during and after drilling to ensure the normal operation of the entire well during the drilling process and after completion.
Type: The type and packaging of petroleum casing are in accordance with SY/T6194-96 "Petroleum Casing", short threaded casing and its coupling and long threaded casing and its coupling. According to the regulations of SY/T6194-96, household casings should be bundled with steel wire or steel belt. The exposed portion of each bushing and connecting thread shall have a protective ring threaded onto it to protect the threads.
Specifications: Domestic casing is stipulated in SY/T6194-96. The length of the casing is not fixed and ranges from 8-13m. However, casing of not less than 6m can be provided, and the quantity shall not exceed 20%.
Appearance: There should be no folding, hair lines, separation, cracks, curling, crusting, etc. on the inner and outer surfaces of the casing. These defects should be completely removed, and the removal depth should not exceed 12.5% of the nominal wall thickness.
Quality requirements: The thread surface of casing and coupling should be smooth, without burrs, tears and other defects that can cause thread breakage and affect the strength and tightness of the joint.
Package:
According to the regulations of SY/T6194-96, household casings should be bundled with steel wire or steel belt. The exposed portion of each bushing and connecting thread should be screwed onto a guard ring to protect the threads.
Chemical composition test:
(1) According to SY/T6194-96. The casing and its couplings are of the same steel grade. Sulfur content <0.045%, phosphorus content <0.045%.
(2) Take chemical analysis samples according to the regulations of GB222-84. Chemical analysis was carried out in accordance with the relevant regulations of GB223.
Oil casing calculation formula:
Outer diameter - wall thickness) * wall thickness * 0.02466 = kg/m (weight per meter)
other:
According to the American Petroleum Institute standard APISPEC5CT 1988 first edition, casing steel grades H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P- 110 and Q-125, a total of 10 types.
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