Abstract: The article deals with the analysis of infeasible problems of optimal production planning of a large dimension. The properties of an infeasible task are formulated for a special linear programming problem. For this problem, the complexity of analyzing infeasible constraints increases linearly with increasing dimension. The data on the planning models of a number of refineries and the patterns of infeasible problems that are determined experimentally are given. Keywords: Planning; Linear programming; Analytical models; Optimization; Task analysis; Oil refineries; optimal production planning; infeasible problem; analyzing infeasibility; special LP problem.