非均匀外载荷对套管承载能力的影响分析

Influence of non-uniform external-pressure load on the load-bearing capacity of casing

基于套管的受力分析,提出了在非均匀外载荷作用下套管应力分析的解析方法,以及简化的套管抗非均匀外载荷作用能力估算的新公式.以目前广泛应用的J55油套管(139.7 mm×8 mm)为例,分析了套管抗外载荷挤压能力随外载荷不均匀性的变化.结果表明,套管抗外载荷挤压能力随外载荷不均匀性的增加迅速降低.按照该公式计算的结果与应用有限元方法所得到的结果误差在15%以内,满足工程要求.说明本文提出的解析方法不仅简便、直观,而且可靠.

An analytical approach for the stress and strength analysis of casing under non-uniform external pressure load is proposed,and the corresponding formula is given.Taking casing J55(139.7mm(8mm) as an example,the variation of the load-bearing capacity of the casing with the non-uniformity degree of external pressure is analyzed.It is shown that the strength of the casing decreases very rapidly with the increase of the non-uniformity degree of external pressure.Therefore,the influence of the non-uniformity degree of external pressure load on the strength of casing must be considered in the strength design and use of casing.The error between the load-bearing capacity of the casing obtained by the analytical method and that computed by finite element method is less than 15%,and it is within the requirement of engineering.This shows that the analytical approach is not only simple and direct,but also reliable.