In the field of oil and gas exploration, casing and tubing are the key pipe materials to ensure drilling safety and achieve efficient oil and gas transportation. The selection of their steel grades directly determines the adaptability of the tubes to complex working conditions such as high pressure, temperature fluctuations, and corrosive media erosion. So how to choose the steel grade for casing and tubing?
Introduction of casing and tubing
Although casing and tubing are both specialized pipe materials for oil and gas, their functional division of labor is clear, which also determines the difference in the focus of steel grade selection.
Casing tube is used to create a good flow channel for oil or natural gas from underground reservoirs to the surface, to protect the well wall, and isolate fluids from each layer. Therefore, it is necessary for the casing tube to have high strength and excellent high-pressure resistance.
Tubing tube is mainly used to transport oil from underground reservoirs to the surface. It needs to withstand high external pressure, corrosion erosion and frequent operational impacts, so the comprehensive requirements for tensile strength, sealing, and corrosion resistance are stringent.
Comparison table of applications of casing and tubing
| Type |
Steel Grade |
Mechanical Properties (Yield strength/Tensile strength) |
Application Scenarios |
|---|---|---|---|
| Conventional strength |
J55/K55 |
379MPa / ≥517MPa (J55),≥655MPa (K55) |
Shallow wells with depth ＜3000m, low-pressure formations, non-corrosive environments; surface/intermediate casing for onshore conventional oil and gas wells |
| Medium-high strength |
N80 (N80-1/N80-Q) |
552MPa / ≥689MPa |
Medium-deep wells with depth 3000-5000m, non-acidic working conditions |
| Corrosion resistance |
L80 |
552MPa / ≥689MPa |
H₂S/CO₂-containing acidic environments |
| High strength |
P110 |
758MPa / ≥862MPa |
Deep/ultra-deep wells with depth 5000-7000m and high-pressure formations |
We can provide high quality API 5CT casing and tubing of multiple dimensions.
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