Construction of «on the average exact» asymptotic solution of the problem on radial distribution of temperature field in a well

The example of the problem on radial distribution of temperature field in a well is used to illustrate the application of a modification of the asymptotic method for solving a number of problems in subterranean thermodynamics. The problem is represented in the form of a set of equations of mixed types for the respective coefficients of expansion, remainder term, and boundary-layer functions. Analytical expressions are constructed for coefficients of zero-order and first-order expansion and for boundary-layer functions. It is demonstrated that the constructed asymptotic formula provides for vanishing of the solution of the averaged problem for remainder term.