Research On The Surface Conductor Installation By Underwater Piling

In order to improve the safety and timeliness of the installation work of surface conductor in deepwater drilling,and to break through the monopoly of foreign technology for underwater piling,this paper is based on hammer-sinking theory,rsearching the underwater piling by literature research and finite element analysis.Aiming at the development model of multi well slots and small wellhead space in the South China Sea TLP platform,five installations were investigated through the drilling,jetting,torpedo anchoring,conductor anchor node and underwater piling,combined with factors such as the operating environment,timelines and costs,found that underwater piling is very suitable for the installation of surface conductor in the South China Sea.By investigating the construction process of underwater piling,contrasting the traditional offshore piling,the difficulties of underwater piling and the applicability of steam hammer,vibratory hammer,diesel hammer and hydraulic hammer for underwater piling.By comparison we can found that the hydraulic hammer is more suitable for underwater piling.The basic theories of dynamic finite element method were briefly introduced.Finite element method was used to simulate piling process in sand and clay.The influence of impact force and soil parameters was analyzed.The variation of dispacement,stess and extra pore water pressure around the pile were studied during continuous piling.Based on the engineering experience of offshore piling,the key factors of underwater piling risk control were analyzed,and preventive measures were also proposed for the risk of high occurrence in piling operations such as refusal hammer,tilting,and slippery piles.