Classification and function of tubing

1. TUBING classification
Tubing is divided into flat tubing (NU), thickened tubing (EU) and integral connector tubing. Flat pipe refers to the pipe end is directly threaded, and is provided with a fitting without thickening. Thickened pipe means that two pipe ends are externally thickened, then threaded, and equipped with a coupling. Integral joint tubing refers to one end through the internal thickened external thread, the other end through the external thickened internal thread, direct connection, no coupling.
2. The role of tubing
① Oil and gas extraction: after oil and gas well drilling and cementing, oil and gas are extracted to the surface by placing tubing in the oil Casing.
② Water injection: when the downhole pressure is not enough, water injection into the well through the tubing.
Steam injection: In the process of hot recovery of heavy oil, heat insulation pipe should be used to input steam into the well.
(4) Acid fracturing.
3. Steel grade of tubing
Pipeline steel types include H40, J55, N80, L80, C90, T95, P110, etc.
N80 is divided into N80-1 and N80Q. The similarity between them is in tensile properties. The difference between them is the delivery state and the impact properties. N80-1 is delivered under normalizing condition, or when the final rolling temperature is higher than the critical temperature Ar3 and the reduced tension is air cooling, hot rolling can be used instead of normalizing. Non-impact energy and non-destructive testing requirements; The N80Q must be treated with tempering (tempering) heat, impact energy in accordance with API 5CT, and nondestructive testing.
L80 is divided into L80-1, L80-9Cr and L80-13Cr. Their mechanical properties and transport conditions are the same. The differences are in use, difficulty of production and price. L80-1 is a common type of tubing, while L80-9Cr and L80-13Cr are highly corrosion-resistant tubing, which are difficult and expensive to produce and are usually used in Wells with severe corrosion.
C90 and T95 are divided into type 1 and type 2, namely C90-1, C90-2, T95-1 and T95-2.
4. Delivery status of commonly used steel products, grades and oil pipelines
Steel delivery condition
J55 tubing 37Mn5 Flat tubing: hot rolling instead of normalizing
Thickened tubing: After thickening, the full length is normalized
N80-1 tubing 36Mn2V Flat tubing: hot rolling instead of normalizing
Thickened tubing: After thickening, the full length is normalized
N80-Q Tubing 30Mn5 full length quenching and tempering
L80-1 tubing 30Mn5 full length conditioning
P110 Tubing 25CrMnMo full length quenching and tempering
J55 coupling 37Mn5 Hot rolled on-line normalizing
N80 coupling 28MnTiB full length conditioning
L80-1 coupling 28MnTiB full length conditioning
P110 coupled 25CrMnMo full conditioning