The wall temperature is an intermediate temperature between the wellbore fluid temperature and farfield temperature. Without any heat loss, the wellbore elements are assumed to be sufficiently long that the fluid temperature is in thermal equilibrium with the well wall. Thus, the well wall temperature, 𝑇 𝑤 , is assumed to be the resulting fluid temperature for an enthalpy of ℎ 𝑖 and pressure of 𝑃 𝑖 if the heat loss term in Equation were zero.