Study on the Separation Technology of HGS and Its Effect on the Temperature Field of the Wellbore During the Multi-gradient Drilling in Deep Water

Abstract

The accurate prediction of annulus temperature is very important during multi-gradient pressure control drilling by the injection of HGS (hollow glass sphere) in deep water. In this paper, the separation efficiency of HGS under different influence factors was studied by the combination of new separation technology and laboratory experiment. Then, considering the influence of HGS separation efficiency on mass transfer and heat transfer process, a transient wellbore temperature calculation model was established by the coupled heat and mass transfer as well as the coupled temperature and pressure based on the energy conservation equation, continuity equation and momentum equation. The model was discretized with the finite difference method and the results calculated with the field data was compared the field measurement data to verify the accuracy of the model. Finally, the sensitivity analysis of the important factors affecting the wellbore temperature and thermos-physical parameters was made, such as separation efficiency, injection rate of the HGS, position of the separator etc. The results are of great reference significance for multi-gradient pressure control drilling in deep water.