TY - JOUR
TI - Change mechanism of transient gas-liquid two-phase flow in wellbore during marine natural gas hydrate reservoir drilling
AU - Wei Na
AU - Sun Wan-Tong
AU - Meng Ying-Feng
AU - Liu An-Qi
AU - Zhao Jin-Zhou
AU - Xu Chao-Yang
AU - Li Hai-Tao
AU - Jiang Lin
AU - Xu Han-Ming
JN - Thermal Science
PY - 2019
VL - 23
IS - 4
SP - 2179
EP - 2187
PT - Article
AB - In the drilling process of a marine natural gas hydrate reservoir, the  original temperature and pressure condition of the hydrate will change due  to the influence of construction, and gas will be released from the  hydrate. The decomposition gas makes the wellbore flow into a complex  gas-liquid-solid multiphase flow after entering into the wellbore, and thus  poses a great threat to the well control security. Accordingly a transient  gas-liquid two-phase flow drift flux mathematical model is established in  this paper. The numerical method is proposed and verified, and an example  analysis is carried out. Finally the change mechanism of transient  gas-liquid two-phase flow in wellbore is obtained. This study provides an  important foundation for the safe design of an offshore gas hydrate.  Meanwhile, it is of great positive significance to find the decomposition  gas and to optimize drilling parameters in the drilling process of a marine  natural gas hydrate reservoir.