深水吸力桩井口稳定性研究

Study on the subsea wellhead stability of suction bucket foundation

吸力桩筒形基础作为海洋深水油气建井的海底井口承载力支撑结构,可以在结构下入海底地层10~20 m深度范围提供足够的承载力,成为未来深水油气建井的新方法。通过吸力桩安装过程井口稳定性分析,建立了根据吸力桩结构和地层参数特征的吸力桩建井承载力及井口稳定性计算模型。模拟实验结果表明:吸力桩的长度、直径及安装完成后的时间效应是影响吸力桩井口承载力的主要因素;在其他条件相同的工况下,吸力桩直径越大、下入地层深度越大、安装完成后承载力恢复时间越长,井口承载力及稳定性越高;模拟实验结果与理论计算结果相对误差约5%,验证了理论计算模型的可靠性。本文研究成果可为吸力桩建井结构优化设计及施工安装提供理论指导。

As a supporting structure for the bearing capacity of the subsea wellhead for offshore oil and gas well construction, the suction bucket foundation can provide sufficient bearing capacity in the depth range of 10-20 meters under the mudline, which will be a new method for deepwater oil and gas well construction in the future. Through wellhead stability analysis during suction bucket foundation installation, a model for calculating bearing capacity and wellhead stability of suction bucket foundation construction shaft is established based on the structure and formation parameters of suction bucket foundation. Simulation experiments show that the length and diameter of suction bucket foundation and the time effect after installation are the main factors affecting the wellhead bearing capacity of suction bucket foundation. Under the same working conditions, the larger the diameter of suction bucket foundation, the greater the depth of the formation and the longer the bearing capacity recovery time after installation, the higher the horizontal bearing capacity and wellhead stability. The relative error between the simulation experiment results and the theoretical results is about 5%, which verifies the reliability of the theoretical calculation model The achievements in this paper can provides a theoretical basis for structural optimization design and construction and installation of suction bucket foundation construction shaft.