In the past the gas industry focused its interest and major investments mainly on the early life of the reservoir and on the development and constant maintenance of production. But times change and currently for depleted gas reservoirs defined as reservoirs in an advanced stage of decline, energy and production should be considered as potential additional energy sources. The ideal time to start managing a reservoir is at its discovery, but Romgaz has a new approach regarding project management implemenatation for depleted gas fields. The strategy presumed, a multidisciplinary team of geophysicists, geologists, reservoir engineers, production engineers and economists. These multidisciplinary teams evaluated existing information and build up a plan for new data acquisitions, the data was integrated, processed, interpreted and correlated in a study with following objectives: - Construct 3D geological model to estimate resources. - Use reservoir engineering to estimate remaining reserves and expected ultimate recovery. - Use results of the study to identify new development opportunities on the field and forecast production scenarios. Success for this challenge depended on: - working as a team; - openness, flexibility, communication, and coordination; - persistence.