Pressure maintenance through immiscible nitrogen injection has proved to be one of the best methods as a secondary oil recovery on depleted and naturally fractured light-oil reservoirs (NFR). The 190 MMscfd of immiscible nitrogen injection project that is currently developed in the Antonio J. Bermudez Complex, a giant NFR in Southern Mexico, is the second large pressure maintenance project in Mexico, after the world famous Cantarell project. A lot of challenges dealing with injection well locations, injection rate control, fracture system effect on nitrogen breakthrough and impact on hydrocarbon gas contamination, have been managed the last six years of project performance. A comprehensive description of the pressure data acquisition program, the importance of the real time and planned chromatography to monitor the reservoir performance, the methodology to determine the net oil recovery contribution and the methods to define the vertical and horizontal efficiencies are described in this paper focused on learning lessons and best practices. The experience gained over the six years of the nitrogen injection project show that this process is beneficial to extend the life of a depleted light oil reservoir as remedial solutions for mature oil fields revitalization.