Dual-barrier single-string well completion schematic is brought on Fig. 1.


Fig. 1. Dual-barrier well completion schematic


The Heat Transfer Coefficient (HTC) is defined by the following equation:

\frac{1}{ r_{ti} \, U} = \frac{1}{r_{ti} \, U_{ti}} + \frac{1}{r_{ti} \, U_t} +
 \frac{1}{d_{ann} \, U_{ann}} +
\frac{1}{r_{ci} \, U_c}  + \frac{1}{r_c \, U_{cem}}  

where

outer radius of tubing

inner radius of the tubing

tubing wall thickness

outer radius of casing

inner radius of the casing

casing wall thickness

wellbore radius by drilling bit

Pipe Flow Heat Transfer Coefficient

Tubing Wall Conductive Heat Transfer Coefficient

Annular Flow Heat Transfer Coefficient

Casing Wall Conductive Heat Transfer Coefficient

Cement Conductive Heat Transfer Coefficient

annular hydraulic diameter

thermal conductivity of fluid moving through the tubing

thermal conductivity of fluid in the annulus

thermal conductivity of tubing material

thermal conductivity of casing material

thermal conductivity of cement


\frac{1}{ r_{ti} \, U} = \frac{2}{\lambda \, {\rm Nu}_{ti}} + \frac{1}{\lambda_t} \, \ln \frac{r_t}{r_{ti}}
+ \frac{1}{\lambda_{ann} \, {\rm Nu}_{ann}} +
\frac{1}{\lambda_c} \ln \frac{r_c}{r_{ci}} + \frac{1}{\lambda_{cem}} \ln \frac{r_w}{r_c} 


where


effective thermal conductivity of the annulus 

Natural Convection Heat Transfer Multiplier


See also


Physics / Thermodynamics / Heat Transfer /  Heat Transfer Coefficient (HTC) / Heat Transfer Coefficient (HTC) @model

Thermal conductivity ] [ Nusselt number (Nu) ] [ Natural Convection Heat Transfer Multiplier ]