水泥环对套管射孔后抗挤毁强度的影响

建立了未射孔套管、不带水泥环射孔套管、外裹水泥环套管的有限元分析模型,对这3种情况下套管的抗挤毁强度进行了对比分析。得出如下重要结论(1)射孔使套管抗挤毁强度显著降低,降低幅度为29%;(2)固结良好的水泥环对于加强射孔套管强度有明显作用,使射孔套管的抗挤毁强度提高188%;(3)水泥环不能抵消射孔对套管抗挤毁强度的伤害,外裹固结良好水泥环的套管,射孔后其抗挤毁强度与无孔套管相比下降156%。

Influence of cement sheath on collapsing strength of perforated casing

The finite element analysis model for blank casing, perforated casing with/without cement sheath is established. A contrast analysis of the collapsing strength of the three kinds of casings is made. Conclusions are drawn as follows: (1) perforation brings about an reduction of the collapsing strength of the casing at a rate of 29%; (2) the collapsing strength of perforated casing can be increased by 18.8% wrapped with well-concreted cement sheath; (3) the cement sheath cannot counteract the harm of perforation to collapsing strength. The collapsing strength of perforated casing with well-concreted cement sheath is 15.6% lower than that of the blank casing.