Abstract:

An analytical model for the lateral load-bearing capacity of conductor and surface casing in deepwater drilling was established on the basis of the pile foundation theories and material mechanics.The axial and lateral loads,variable stiffness of casing string and the nonlinear response between casing string and soil were considered in deepwater drilling.A numerical method was adopted to solve this model.The analyses on lateral displacement,angular distortion,bending moment,shear force and soil force acted on casing string show that the affection of lateral load is focus on the upper section of casing string,and the vertical load has little effect on the lateral loading capacity of casing string.When the casing string reaches a certain depth,its lateral loading capacity has little change with the depth,but the type of soil has a certain effect on lateral loading capacity of casing string.It is necessary for deepwater drilling to analyse the geological data in shallow formation and mechanical stability of wellhead.

Key words: deepwater drilling, conductor, surface casing, lateral load-bearing capacity, vertical load, analytical model

摘要：

根据桩基和材料力学理论,建立了适于深水钻井的导管和表层套管横向承载能力分析模型。模型中考虑了深水钻井中横向和竖向载荷的共同作用、可变的管柱抗弯刚度以及管柱与地基间的非线性响应等特征。通过对模型进行数值求解,对不同影响因素下沿管柱的横向位移、转角、弯矩、剪力和地基反力进行了分析,结果表明:载荷对管柱的作用集中在管柱上部较短的一段区域;竖向载荷对管柱横向承载力影响不大;套管下入深度超过一定值后,较大的下入深度对其横向承载能力几乎没有影响;海底浅部地层地基类型对管柱的横向承载能力有一定影响;有必要通过现场取样获得浅部地层的地质资料,对深水钻井井口力学稳定性进行分析。

关键词: 深水钻井, 导管, 表层套管, 横向承载力, 竖向载荷, 分析模型