This paper provides an analytic solution in Laplace space for the heat distribution in two nearby layers undergoing heat injection at variable rates. The heat content in the layers undergoing thermal injection, divided by the cumulative net-injected heat, is known as the heat efficiency. In this treatment, the thermal properties of the layers, the thickness of the layers undergoing heat injection, and the intervening layer can have any values. The overburden and underburden are semi-infinite.
Examples are given for two sets of thermal properties and three values of the intervening layer's thickness. Only a constant rate of heat injection is considered in the examples.
Results indicate that significant thermal interaction occurs at an intervening layer thickness as great as 45 ft, with the effect being faster and more pronounced the thinner the intervening layer.