深水钻井井筒全瞬态传热特征

深水钻井作业期间的井筒温度是深水钻井设计和安全钻井的重要基础数据。基于深水钻井液循环时井筒与地层和海水的传热机理，建立了全瞬态深水钻井液循环温度计算模型，模型与Holmes实验井实测温度吻合程度较高。利用一口深水模拟井数据，分析了水深、水温、隔水管保温层等因素对钻井液循环温度的影响。研究表明，深水井筒温度随井深变化幅度小，一般不超过30℃；水深相差500 m时，一般会使井底温度相差约5℃，但基本不影响钻井液出口温度；隔水管保温层对井筒温度影响大，而季节变化对深水钻井液的循环温度基本没有影响。

Full transient analysis of heat transfer during drilling fluid circulation in deep-water wells

Wellbore temperature is a significant parameter to well design and drilling safety during deep-water drilling operations.Based on heat transfer mechanisms among wellbore,formation and sea water during the drilling fluid circulation in deep-water drilling,we developed a full transient model for computing temperatures of circulating drilling fluids,which was verified effective by the remarkable consistency of computed temperatures with measured ones from a Holmes experimental well.In addition,effects of water depth,water temperature and riser insulating layers on temperatures of circulating drilling fluids were analyzed via a deep-water simulation well.The simulation indicated that the range ability of temperatures along the deep-water wellbore profile with depth was not great,normally less than 30℃.The difference of the bottom hole temperature would be commonly about 5℃ as water depth increased 500m more,however,it generally made little difference to the outlet temperature of drilling fluids.Riser insulating layers had a considerable effect on wellbore temperatures,while seasonal changes contributed little to wellbore temperatures of circulating drilling fluids.