Highly anti-collapsing casing is a special technical product which adopts technologies such as optimized material components, physical dimension, mechanical property and residual stress to enable the anti-collapsing strength under external pressure to exceed API standard value. It applies to working conditions of shale gas well, deep well, extra-deep well and staged fracturing of casing, etc. Optimized design of manufacturing techniques can improve the anti-collapsing strength to reach 115%~180% of API value. Anti-collapsing casing product has already passed the detection carried out by a domestic authority in 2008, and is used widely in domestic oil fields. The new sulfur-resisting and anti-collapsing casing also has passed the authority’s detection and oil fields’ practice testing.
API SPEC 5CT specification for casing and tubing
API TR 5C3 Technical Report on Equations and Calculations for Casing, Tubing and Line Pipe Used as Casing or Tubing; and Performance Properties
To ensure the excellent anti-collapsing property, the ellipse of casing’s OD should not exceed 0.5%; inhomogeneity level of wall thickness is not more than 10%; the grain size is ASTM E112, grade 8 or smaller; decarburization depth of the inner or outer surface is not more than 5% of wall thickness; residual compressive stress from circumferential directions is not more than 20% of material yield strength. To different OD and D/T, the anti-collapsing strength of anti-collapsing casings made in KPE can exceed 15%-80% of API standard values.
Range of product specification
OD: Φ114.3mm~Φ219.08mm；WT: 5.21mm~22.2mm.