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If the flowrate is not vanishing during the stationary lift (

LaTeX Math Inline
body\sum_{a = \{w,o,g \}} |q_\alpha^{k-1}| > 0
) then  
LaTeX Math Inline
bodyT^{k-1}
 can be calculated iteratively from previous values of the wellbore temperature 
LaTeX Math Inline
bodyT^k
 as:


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anchor1
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T^{k-1} = \frac{\bigg( \sum_\alpha \rho_\alpha^k \ c_{p \alpha}^k \ q_\alpha^k \bigg)  T^k +   \sum_\alpha \rho_\alpha^k \ c_{p \alpha}^k \ (q_\alpha^{k-1} - q_\alpha^k) \, (T_r^k + \epsilon_\alpha^k \delta p^k )}{\bigg( \sum_\alpha \rho_\alpha^{k-1} \ c_{p \alpha}^{k-1} \ q_\alpha^{k-1} \bigg) } 



Expand
titleDerivation



LaTeX Math Block
anchordivT
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(\rho \,c_{pt})_p \frac{\partial T}{\partial t} 
 
- \ \phi \sum_{a = \{w,o,g \}} \rho_\alpha \ c_{p \alpha} \ \eta_{s \alpha} \ \frac{\partial P_\alpha}{\partial t}  
 
+ \bigg( \sum_{a = \{w,o,g \}} \rho_\alpha \ c_{p \alpha} \ \epsilon_\alpha \ \mathbf{u}_\alpha \bigg)  \nabla P
 
+ \bigg( \sum_{a = \{w,o,g \}} \rho_\alpha \ c_{p \alpha} \ \mathbf{u}_\alpha \bigg) \  \nabla T 
 
 - \nabla (\lambda_t \nabla T) =  \frac{\delta E_H}{ \delta V \delta t}

The wellbore fluid velocity 

LaTeX Math Inline
bodyu_\alpha
 can be expressed thorugh the volumetric flow profile 
LaTeX Math Inline
bodyq_\alpha
 and tubing/casing cross-section area 
LaTeX Math Inline
body\pi r_f^2
 as:

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anchor1
alignmentleft
u_\alpha = \frac{q_\alpha}{\pi r_f^2}

so that 

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anchorN3VMD
alignmentleft
\bigg( \sum_{a = \{w,o,g \}} \rho_\alpha \ c_{p \alpha} \ \mathbf{u}_\alpha \bigg) \  \nabla T 
 =  \frac{\delta E_H}{ \delta V \delta t}




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