What is oil casing?

Oil casing is an important equipment for oil drilling. Its main equipment also includes drill pipes, drill collars, steel pipes for small-diameter drilling, core pipes and casings, etc.

Oil casing is a steel pipe used to support the well wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. Each well uses several layers of casing based on different drilling depths and geological conditions.

It is made of geological drilling steel by hot rolling process or cold drawing process. The steel number is represented by "geology"---DZ. Commonly used casing steel grades include DZ40, DZ55, and DZ753.

1.Use

Oil casing is mainly used for drilling oil and gas wells and transporting oil and gas. It includes oil drilling pipe, oil casing and oil pumping pipe.

Oil drill pipe is mainly used to connect drill collars and drill bits and transmit drilling power.

Oil casing is mainly used to support the well wall during the drilling process and after well completion to ensure the drilling process and the normal operation of the entire oil well after completion. The pumping pipe mainly transports oil and gas from the bottom of the oil well to the surface.

2.Type

According to SY/T6194-96 "Petroleum Casing", there are two types: short threaded casing and its couplings and long threaded casing and its couplings.

3. Specifications and appearance quality

(1) Domestic bright pipes comply with the regulations of SV/T6194-96. The length of bright pipes is not full length, and its range is 8-3m. Among them, casings not shorter than 6m can be provided, but their number must not exceed 20% of the total quantity.

(2) The internal and external surfaces of the casing shall be free of folds, hairlines, separation layers, cracks, folds and scars. These defects should be completely removed and the removal depth should not exceed 12.5% of the nominal wall thickness.

(3) The surface of the casing and coupling pattern should be smooth, and no burrs, tears, or other defects sufficient to interrupt the pattern and affect the strength and tight connection are allowed.

Common Material：

H40, J55、K55、N80、L80、C90、T95、P110、Q125、V150 etc.

Casing end processing form：

Short round thread, long round thread, trapezoidal thread, special buckle, etc.

Weight Calculation Formula：

(OD-Thickness)*Thickness*0.02466=kg/m

What pipe is used for oil drilling?

Oil casing is a type of steel pipe. Its characteristics are mainly used to support the well wall during the drilling process and after well completion to ensure the drilling process and the normal operation of the entire oil well after completion.

Petroleum special steel pipes are mainly used for drilling oil and gas wells and transporting oil and gas. It includes oil drilling pipe, oil casing and oil pumping pipe.

Oil drill pipe is mainly used to connect drill collars and drill bits and transmit drilling power. The pumping pipe mainly transports oil and gas from the bottom of the oil well to the surface. During use, the strength of the oil pumping pipe is required to ensure the normal extraction and transmission of crude oil and gas.

Oil casing is the lifeline to maintain the operation of oil wells. Due to different geological conditions and complex stress conditions downhole, tension, compression, bending and torsion stresses act comprehensively on the pipe body, which places higher requirements on the quality of the casing itself. Once the casing itself is damaged for some reason, the entire well may be reduced in production or even scrapped.

According to the strength of the steel itself, casing can be divided into different steel grades, namely J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. Different well conditions and well depths require different steel grades. In corrosive environments, the casing itself is also required to have corrosion resistance. In places with complex geological conditions, the casing is also required to have anti-collapse properties.