API 5CT OCTG Pipe

OCTG pipe are steel pipes used to support the walls of oil and gas wells to ensure the normal operation of the entire oil well after drilling and completion. Each well needs to use several layers of casing according to different drilling depths and geological conditions.After casing under the well to use cement cementing, it and tubing, drill pipe is different, can not be reused, belongs to one-time consumption material.Therefore, the consumption of casing accounted for more than 70% of all oil well pipe

It is a kind of large-diameter pipe, plays the role of fixing oil and gas oil wall or well hole.The casing is inserted into the hole and secured with cement to prevent the hole from collapsing and to ensure the circulation of drilling mud to facilitate drilling.

Casing is classified by use as: pipe, surface casing, technical casing and reservoir casing.

Surface casing

- Protect drilling Wells from contamination by shallow water and gas zones,

- Supports wellhead equipment and maintains the weight of other layers of casing.

Technology casing

- Separate the pressure on the different layers to allow fluid flow and protect the production casing.

- To install anti-blowout device, Leak-proof device and liner in the well.

Oil layer casing

- Extracting oil and gas from deposits beneath the surface.

- Used to protect drilling and to stratify drilling mud.

Oil casing is the lifeline to maintain the operation of oil wells. Due to the different geological conditions, the down hole stress state is complicated, and the combined action of tensile, press, bending and torsion stresses on the pipe body, which puts forward higher requirements on the quality of the casing itself. Once the casing itself is damaged for some reason, the entire well may be reduced or even scrapped.

According to the strength of the steel itself, the casing can be divided into different steel grades, namely J55, K55, N80, L80, C90, T95, P110, Q125, V150, etc. Different well conditions and depths have different steel grades. In a corrosive environment, 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 performance.