Ramey's Wellbore Heat Transmission Revisited

Summary In this work we assess Ramey's classic method for the calculation of temperatures in injection and production wells. We show that Ramey's method is an excellent approximation, except for an early transient period in which the calculated temperatures are significantly overestimated. We present a simple graphical correlation to estimate the length of this early transient period. We further demonstrate that Ramey's procedure for the estimation of overall heat-transfer coefficients holds good only for large values of the Fourier dimensionless time. Finally, we illustrate the results of this work by an example calculation of wellhead temperature in a flowing oil well.