TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractMajority of the largest Russian oil fields are at the stage of depleting active resources. A problem of reactivating development of the marginally profitable old oil fields is becoming increasingly vital due to decrease in discovering of new large oil deposits. This is also witnessed by the worldwide experience of the oil industry development.One of the major problems of the late stage development of the multilayer oil fields is a task of identifying accumulations of residual oil deposits and substantiation of geological and technical activities for the purpose of their maximal recovery.The example of horizon D 1 productive sediments in Block III of Romashkiskoe oil field Pavlovskaya area has served as a basis for implementing a set of activities to increase the effectiveness of developing a multilayer oil field at the late stage of operation, including re-interpretation of the primary geophysical data, re-appraizal of the initial oil in place, analysis of the development status, identification of areas containing residual oil reserves and justification of activities aiming to involve such reserves into the drainage process as well as analysis of all the works performed effectiveness.The results of the works performed allowed adding recoverable oil reserves by 3.89 %, optimizing the formation and the bottomhole pressure values through water injection and product withdrawal and during the five year period allowed to additionally produce 599.1 thousand tons of oil accounting for 55.5% of the total oil production within the block during the period under consideration.By the beginning of the re-activating activities implementation the production watercut amounted to 88.6 % with the current oil recovery factor amounting to 44.3 %.

TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractMajority of the largest Russian oil fields are at the stage of depleting active resources. A problem of reactivating development of the marginally profitable old oil fields is becoming increasingly vital due to decrease in discovering of new large oil deposits. This is also witnessed by the worldwide experience of the oil industry development.One of the major problems of the late stage development of the multilayer oil fields is a task of identifying accumulations of residual oil deposits and substantiation of geological and technical activities for the purpose of their maximal recovery.The example of horizon D 1 productive sediments in Block III of Romashkiskoe oil field Pavlovskaya area has served as a basis for implementing a set of activities to increase the effectiveness of developing a multilayer oil field at the late stage of operation, including re-interpretation of the primary geophysical data, re-appraizal of the initial oil in place, analysis of the development status, identification of areas containing residual oil reserves and justification of activities aiming to involve such reserves into the drainage process as well as analysis of all the works performed effectiveness.The results of the works performed allowed adding recoverable oil reserves by 3.89 %, optimizing the formation and the bottomhole pressure values through water injection and product withdrawal and during the five year period allowed to additionally produce 599.1 thousand tons of oil accounting for 55.5% of the total oil production within the block during the period under consideration.By the beginning of the re-activating activities implementation the production watercut amounted to 88.6 % with the current oil recovery factor amounting to 44.3 %.