水泥环弹性模量对套管外挤载荷的影响分析

Effects of cement sheath elastic modulus on casing external collapse load

利用弹性力学解析及有限元方法,分别研究了均匀地应力和非均匀地应力条件下水泥环弹性模量对套管外挤载荷的影响规律。研究结果表明,增加水泥环弹性模量对套管外挤载荷有一定的减缓作用,但效果远没有降低水泥环弹性模量明显。理想水泥环的性能应该是高强度、低刚度。在固井作业时,对软地层推荐采用弹性模量大的水泥,对硬地层推荐采用弹性模量小的水泥。

By the elastic mechanics mathematical method and finite element analysis, the effect of cement sheath elastic modulus on casing external collapse load was researched on the conditions of uniform and non-unifoml in-situ stress. The results show that the casing external collapse load could be lowered to some extent by increasing the cement sheath elastic modulus. But the effect of increasing elastic modulus is much less than that of decreasing the elastic modulus of cement sheath. The ideal performance of cement sheath should be high intensity with low stiffness. The cement with high elastic modulus is recommended in .soft formation, and the cement with low elastic modulus is preferential in hard formation.