| Abstract: | A variational formulation is given for the problem of determining the limiting equilibrium of retained viscoplastic oil during its displacement with water from a stratified bed. It is shown that the basic approximation of the formulation admitting of an effective solution by the methods of the plane problem of non-linear filtering /1–5/ follows naturally from the variational formulation proposed, provided that the class of functions in which the solution is sought is restricted. Some estimates of the volume of the bed from which the oil is displaced are obtained on the basis of the variational formulation. |
