The Mathematical Model of Integrated Coupling of Gas Reservoir-Wellbore-Choke in Sulige Gas Field, China

Table 1

and for different flow pattern.

Flow pattern	Diffusion coefficient	Drift velocity (m/s)
Bubble flow	1.2
Slug flow
Stirred flow
Annular flow		0

is the density of liquid phase (kg/m³), is the density of the gas phase (kg/m³), is surface tension (N/m), is the acceleration of gravity (m/s²), is the gas phase apparent velocity (m/s), is the boundary of transition of bubble flow to slug flow (m/s) (), is the boundary of transition of stirred flow to annular flow (m/s) (), is the boundary of transition of bubble flow to diffuse bubble flow (m/s) ().