中文摘要：

深水表层土壤松软,导管通常采取喷射的方式下入,井口径向稳定性能薄弱,尤其在深水新区块探井海底地质情况不明确、浅层土质强度参数不准确的情况下,水下井口径向稳定性问题尤为重要.为提高水下井口径向载荷的稳定性,针对现场作业中表层套管在固井前循环及注水泥固井期间出现的井口下沉现象,进行导管在表层套管固井期间的径向受力情况分析,结合现场作业实践,提出了防止井口下沉的方法,并且在作业实践中得到了成功应用,提高了水下井口径向载荷的稳定性,有效促进了深水表层作业的顺利、安全进行,保证了深水钻井的安全性.

英文摘要：

The deepwater surface soil is loose and soft, the pipe is lowered by ejection generally, and the wellhead radial stabil-ity performance is weak. In particular, when the subsea geology of well exploration in the deepwater new block is not clear and the intensity parameters of superifcial layer soil are inaccurate, the radial stability of underwater wellhead is especially important. In order to improve the stability of radial load of underwater wellhead, based on the wellhead sinking of surface casing during the circulation before cementation and during the cementing period in the site operation, the radial stress of pipe during the surface casing cementation period is analyzed; furthermore, according to the site operation practices, the method for wellhead sinking prevention has been raised and successfully applied in the operation practices. It improved the stability of radial load of underwater wellhead, effectively promoted the smooth and safe deepwater surface layer operation, and guaranteed the safety of deepwater drilling.