In the process of thermal recovery of heavy oil, the casing in oil production wells is subjected to complex stress conditions, which may cause potential damage and affect the lifecycle of the casing. The factors influencing the casing instability and the mechanism of the process in thermal production wells need to be comprehensively researched, particularly in the case where oil extraction is accompanied by sand production. In this paper, the authors have applied the three-dimensional finite element method to simulate the casing instability characteristics in the sand production section of a thermal recovery well. We have also analyzed the effect of sand production, perforation parameters, and the casing strength parameters on the axial and circumferential instability of the casing. The results show that sand production can cause a significant decrease in the lateral support of the casing and greatly reduce the buckling resistance of the casing in a thermal horizontal well. With increase in perforation diameter and perforation density, the critical buckling load of the casing decreases. On the other hand, the buckling load is less affected by the perforation phase. When the combination of the perforation density and perforation phase angle results in a bigger number of perforation holes in the row, it can significantly reduce the casing collapse strength and increase the risk of circumferential instability. The research results provide a theoretical basis in the design of casing in horizontal sections of thermal production wells.

在稠油热采过程中，采油井套管受到复杂的应力条件，可能造成潜在损坏，影响套管的生命周期。热采井套管失稳的影响因素和过程机理需要综合研究，特别是在采油伴随出砂的情况下。在本文中，作者应用三维有限元方法模拟了某热采井出砂段套管失稳特性。我们还分析了出砂、射孔参数和套管强度参数对套管轴向和周向失稳的影响。结果表明，在水平热井中，出砂会使套管的侧向支撑显着降低，大大降低套管的抗屈曲能力。随着射孔直径和射孔密度的增加，套管的临界屈曲载荷减小。另一方面，屈曲载荷受穿孔阶段的影响较小。当射孔密度和射孔相位角相结合导致行内射孔数量较多时，会显着降低套管坍塌强度，增加周向失稳风险。研究成果为热力生产井水平段套管设计提供了理论依据。