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

Abstract

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.