摘要
深水钻井时水下井口承受的复杂作用力可能导致其稳定性存在问题。根据深水钻井水下井口系统整体受力分析,建立了井口力学稳定性分析方法,该方法综合考虑了海洋环境载荷、钻井船或平台漂移、隔水管力学性能、套管柱与地层之间的非线性响应等因素的影响,可以实现井口力学性能分析。算例分析表明,水下井口的横向偏移及弯矩随张力比和海流流速的增加而大幅增大,顶张力过大会引起井口稳定性变差;随着钻井船或平台漂移量的增加,井口的横向偏移和弯矩近似线性增加,控制好钻井船或平台的漂移非常重要;由于井口承受弯矩的能力有限,较大海流流速情况下可能造成井口失稳;提高导管抗弯强度、控制泥线处管柱冲刷、获取浅部地层的取样数据等措施可以增强井口稳定性。
As drilling operation moves into deeper water, the stability of subsea wellhead may be influenced by the complex forces. According to mechanical analysis of subsea wellhead for deepwater drilling, a comprehensive stability analysis method is established. The marine environmental loading, drilling vessel or platform drifting, riser mechanical behavior, nonlinear behavior between casing string and formations are considered. Case analysis shows, the lateral displacement and bending moment of wellhead increases along with riser top tension ratios and current velocities. The bigger top tension will cause the wellhead to be over-pulled and increase the probability of wellhead collapse. As the mean drifting of drilling vessel or platform increases, the wellhead displacement and bending moment nearly linear enlarges. The greater current velocity may result in wellhead instability because of its limited bearing moment capacity. Therefore the drifting control is very important to subsea wellhead stability. The wellhead stability may be improved by taking measures such as enhancing the conductor bending strength, controlling scour depth on seabed, getting geological data sampling of shallow formations.
出处
《石油钻采工艺》
CAS
CSCD
北大核心
2008年第6期1-4,15,共5页
Oil Drilling & Production Technology
基金
国家863计划“深水钻完井关键技术”课题部分研究内容,课题编号:2006AA09A106。
关键词
深水钻井
水下井口
隔水管
稳定性
力学分析
deepwater drilling
subsea wellhead
riser
stability
mechanical analysis
