@Article{fdmp.2020.011145,
AUTHOR = {Miao He, Yihang Zhang, Mingbiao Xu, Jun Li},
TITLE = {A Multiphase Wellbore Flow Model for Sour Gas “Kicks”},
JOURNAL = {Fluid Dynamics \& Materials Processing},
VOLUME = {16},
YEAR = {2020},
NUMBER = {5},
PAGES = {1031--1046},
URL = {http://www.techscience.com/fdmp/v16n5/40303},
ISSN = {1555-2578},
ABSTRACT = {This study presents a new multiphase flow model with transient heat
transfer and pressure coupling to simulate HTHP (high temperature and high pressure) sour gas “kicks” phenomena. The model is intended to support the estimation of wellbore temperature and pressure when sour gas kicks occur during
drilling operation. The model considers sour gas solubility, phase transition and
effects of temperature and pressure on the physical parameters of drilling fluid.
Experimental data for a large-diameter pipe flow are used to validate the model.
The results indicate that with fluid circulation, the annulus temperature with H<sub>2</sub>S
kicks is the highest, followed by CO<sub>2</sub>, and CH<sub>4</sub> is the lowest. The phase transition
point of H<sub>2</sub>S is closer to wellhead compared with CO<sub>2</sub>, resulting in a faster expansion rate, which is more imperceptible and dangerous. With fluid circulation, the
drilling fluid density and plastic viscosity both first decrease and then increase
with the increase in the well depth. The bottom hole pressure when H<sub>2</sub>S kicks
is greater than that for CO<sub>2</sub> with the same amount of sour gas, and the pressure
difference gradually increases with the increase of H<sub>2</sub>S/CO<sub>2</sub> content. In addition,
a parametric sensitivity analysis has been conducted to evaluate qualitatively and
rank the influential factors affecting the bottom hole temperature and pressure.},
DOI = {10.32604/fdmp.2020.011145}
}