For the first time presented are method and equations of elastic material balance, which enable to control development of Mesozoic oil pools in fractured reservoirs in "Grozneft" Concern zone of activity. Analytically determined are: initial oil reserves, oil recovery due to water intrusion from oil pool outline, flooded and not flooded pool volumes. It is noted, that the need for data on secondary porosity distribution and pore volumes per pool depth arises only during determination of initial and current water-oil contacts.