深井超深井套管损坏机理与强度设计考虑因素

深井超深井开发过程中，套管损坏带来重大经济损失和安全隐患。分析了深井超深井套管损坏主要形式和损坏机理， 主要包括轴向力引起的脱扣和失稳、非均布载荷产生挤毁破坏、剪切变形、螺纹密封失效、磨损、腐蚀等。认为对于深井超深井 套管，尤其是气井必须引入强度设计、密封设计、防腐蚀设计，需要从外载的计算、强度模型的选择、塑性岩石蠕动引起的载荷、 技术套管磨损、温度效应、螺纹的密封性以及套管本身强度的选择等方面进行研究。建议采用安全系数和失效概率相结合的套 管柱强度评价方法，进一步完善套管设计规范与标准。

Casing failure mechanism and strength design considerations for deep and ultra-deep wells

During deep and ultra-deep well developing, casings failure has brought great economic loss and safety hazards. Cas- ing failure forms and mechanism are analyzed, which mainly includes axial force causing thread off and destabilization, non-uniform loading resulting to collapse, shear deformation, thread losing effectiveness, internal wall wear and corruption. When complete a deep and ultra-deep well casing program, especially a gas well, strength design, thread sealing design and anticorrosion design are needed to introduce. Meanwhile, many factors including external loadings, casing strength models selection, plastic rock creep stress, intermediate casing wear, temperature effect, thread air tight ability are necessarily considered. The coeficient of safety design method is suggested to combined failure probability method in deep and ultra-deep well casing strength design and assessment. The domestic casing criteria and standards are proposed to improve.