油层出砂引起采油套管损坏的力学分析

基于普氏自然平衡拱理论，并考虑套管与地层的相互作用，对空洞的形态进行了分析，得出出砂空洞的顶部压力拱形状为抛物线，给出了油层出砂形成空洞后淘空段套管所受轴向力的计算公式。将套管损坏近似看成两端固定压杆的失稳弯曲，建立了套管失稳破坏与出砂量之间的关系，并分析了不同的钢级和壁厚对套管发生失稳破坏时出砂量的影响，指出对于出砂严重的油田，其油层段应尽量使用高强度、大壁厚的套管。该研究不但有助于严重出砂油田的套管设计，而且在实际生产中还可以通过监测出砂量来判断套管是否已发生损坏，从而保证采取及时、有效的防砂方法，达到防止套管损坏的目的。

Mechanical analysis of production casing damage due to sand production

Based on the theory of M, M, PROMOJIYFAKONOV, cavity configuration was analyzed considering the interaction of casing and formation, The shape of cavity was a kind of para curve. The calculation formula of the axial force acting on the casing at the cavity was derived. By considering casing damage as destabilization bending of compression column with fixed terminals, the relation between casing dana,age and sand production volume was established. The influence of different steel grade and wall thickness on sand production volume was analyzed while casing is destabilized. It is shown that the casing with high intensity and big wall thickness should be used in the oil fields with serious sand production. The results can help to design casing for the fields, and judge if casing damage has taken place by monitoring sand production volurae. So effective measures of sand control can be taken to prevent casing damage.