The inverse problem for the estimation of reservoir parameters of the zone of non-pay rocks is formulated using the actual data on the dynamics of the average reservoir pressure. Examples of solving the inverse problem are considered based on numerical modeling and the methods of optimal control theory (adjoint methods). The influence of different factors on the estimation accuracy of the parameters identified is studied. It is shown that the solution of the inverse problem at a realistic amount and accuracy of reservoir pressure measurements make it possible to obtain an equivalent model of the zone of non-pay rocks that accurately predicts the volumes of gas inflowing to the zone of active development from the region of nonpay reserves.