地面钻井双层套管剪切变形的应力传递特性

Stress Transfer Characteristics of Double Casing Shear Deformation in Surface Borehole

针对采动条件下钻井井身易失稳破断的难题,采用数值模拟的方法,研究了地面钻井双层套管剪切变形过程中的应力传递特性,结果表明:双层套管剪切变形过程中,外层套管的峰值应力和应力集中区面积均大于内层套管;随双层套管剪切位移增大,应力传递系数整体呈现先快速增大再缓慢增大的变化趋势;此外,随填充层厚度增大和填充材料弹性模量降低,双层套管的应力传递系数逐渐降低。在上述研究基础上,提出了增大填充层厚度和选择柔性填充材料的井身结构优化建议。

Aiming at the problem of failure and fracture of drilling well under mining condition,through using numerical simulation,we researched the stress transfer feature in the shear deformation progress of double casing for surface drilling.Results show that the peak stress and the stress concentration area of outer casing are all bigger than the inner casing;the stress transfer coefficient presents a variation trend which increases quickly and then increases slowly;besides,the stress transfer coefficient of double casing decreases with increase of thickness of fill layer or decreases with elasticity modulus of filling material.Therefore,the structure optimization suggestion of borehole is:increasing the thickness of the filling layer and selecting the flexible filling material.