海底浅部地层性质对深水钻井井口稳定性的影响

Impact of the seabed soil properties on the stability of subsea wellhead for deepwater drilling

苏堪华 管志川 龙芝辉

SU Kanhua GUAN Zhichuan LONG Zhihui

重庆科技学院石油与天然气工程学院，重庆　401331 中国石油大学石油工程学院，山东东营　257061

Chongqing University of Science and Technology, Chongqing 401331, China China University of Petroleum, Dongying 257061, China

为了解深水海域海底泥线以下的浅部地层强度对深水钻井水下井口及其以下套管柱的支撑作用的大小，通过理论分析建立了软土工程性质与水下井口竖向和横向稳定性之间的关系，并对影响水下井口稳定性的相关规律进行了研究。结果表明，黏性土的不排水抗剪强度和黏着系数、砂性土的内摩擦角和水下容重对水下井口竖向稳定性的影响都很大；水下井口横向稳定性主要受海底较浅部土层性质的影响，黏性土的不排水抗剪强度和砂性土的内摩擦角对井口横向稳定性影响最大。选择海底地层强度大的位置进行钻井作业、作业前进行海底浅部地层数据取样、合理确定相关计算参数等措施可以提高水下井口的稳定性。

The seabed soil plays a supportive role to the subsea wellhead and conductors, the properties of soil determines whether the stability of the subsea wellhead. Through theoretical analysis, the relationship of the seabed soil properties and the vertical and lateral stability of subsea wellhead were established. Results illustrate that the undrained shear strength and adhesive coefficient of the clay and the internal frictional angle and submerged unit weight of the sand have great effect to the vertical stability of subsea wellhead. And the character of shallow soil is the main affecting factor to the lateral stability of subsea wellhead. The undrained shear strength of clay and the internal frictional angle of sand have the maximum effect on the lateral stability of the wellhead. Selection of the spud in location with hard soil for drilling operation, acquiring the geological sample data of shallow seabed before drilling, and reasonable determination of relevant parameter value, can improve the stability of subsea wellhead.