The drill string of deepwater riserless operational mode exposed in seawater bears complex forces during drilling operation. Consider the drilling platform motion and wave-current interaction, a dynamic model and numerical solution method of drill string during riserless drilling operation was established. Example analysis illustrated that the long term drift of platform has certain impact on the drill pipe deformation and stress. To meet the strength requirements, the smaller diameter drill string is required. The longer length of drill string below mudline causes the greater pulling force on the top of drill string exposed in seawater. Thereby the deformation and stress of the drill string near the mudline can be improved.%深水无隔水管钻井环境下,裸露在海水中的钻柱受到复杂动力作用.在考虑深水钻井平台运动、波流共同作用情况下,建立了深水无隔水管环境下钻柱受力理论模型.算例分析表明,钻井平台的慢漂运动对裸露在海水中的钻柱变形和受力有一定的影响.在满足强度要求的情况下,尽量选用直径较小的钻柱.无隔水管环境下,裸露在海水中的钻柱在泥线以下的长度越长,则钻柱上部所受拉力越大,从而可使泥线附近钻柱段的变形和受力情况得到改善.
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