In case of flow in a simple one-casing well completion (see Fig. 1) the HTC is defined by the following equation:
\frac{1}{ d_{ci} \, U} = \frac{1}{d_{ci} \, U_{ci}} + \frac{1}{\lambda_c} \ln \frac{d_c}{d_{ci}} + \frac{1}{\lambda_{\rm cem}} \ln \frac{d_w}{d_c}
|
where
wellbore diameter (with radius | ||
outer diameter of the casing (with outer radius | ||
inner diameter of the casing (with inner radius | ||
| casing wall thickness | ||
thermal conductivity of the casing material | ||
thermal conductivity of cement | ||
| thermal conductivity of wellbore fluid | ||
| heat transfer coefficient (HTC) between inner surface of the casing and moving fluid | ||
Nusselt number for the moving wellbore fluid with account of its contact with inner surface of the casing | Fig. 1. Schematic of a typical multi-layer structure around single-barrier (casing) well completion |