Wellbore Temperature-Pressure Coupling Model Under Deep-Water Gas Well Intervention Operation

The accurate forecast of wellbore temperature and pressure during intervention operations is critical to the long-term exploitation of deep-water oil and gas resources. A wellbore temperature prediction model was constructed in the seawater and formation sections based on Hasan and Kerber’s gas-liquid two-phase flow heat transfer model and integrated with the features of intervention operations. Simultaneously, the heat exchange produced by the change in fluid flow rate caused by the tool placement was evaluated. The wellbore pressure prediction model is developed in the intervention tool and intervention operation sections, and the friction gradient is modified by introducing the intervention operation.The established temperature and pressure model is coupled and solved iteratively, and the disturbance law of the wellbore temperature and pressure field induced by the intervention operation is investigated. The results show that the pressure in the wellbore gradually decreases when the tool is removed; the temperature at the mudline of the wellbore with high gas production is higher, and the wellhead pressure is low; the tool size is weakly sensitive to the wellbore; and the wellbore temperature and pressure are weakly sensitive to the running speed. The aforesaid findings have some guiding relevance for the design of the intervention operation plan, as well as the prediction and prevention of hydrate in the wellbore during deep-water gas well cleaning and blowout.