Recent evolution in oil field technologies has made a great revolution in the oil and gas industry all over the world leading to the emerging development of intelligent fields (I-Fields)1, 2, 3, 4. The integration of I-Field technologies whether downhole or at surface, coupled with communication networks along with sophisticated simulation and monitoring applications has lead to significant advancements not only in monitoring and control capabilities, but rather also in decision making processes5. Therefore, the overall system upgrade has resulted in an enhancement of the field surveillance, which will lead to higher levels of oil production in these assets as a consequence of Saudi Aramco's development strategy for these fields. A comprehensive redevelopment and I-Field transformation of three elderly remote onshore oil fields in Saudi Arabia has taken place where extensive drilling and workover programs have been reinitiated to complete both oil production and peripheral water injection wells, and equip them with the latest downhole production technologies. The project has also involved construction of new oil and gas processing and water injection facilities, which are being linked with the wells via a state of the art fiber optic communication network for controlling both subsurface and surface parameters and data surveillance in real-time. Further integration of I-Field components, such as Permanent Downhole Monitoring Systems (PDHMS), Smart Well Systems, Multiphase Flow Meters (MPFM), Single Phase Flow Meters, pressure and temperature sensors with specially tailored monitoring, and simulation software has facilitated the development and implementation of optimized production and injection strategies. This paper will discuss the development strategy of the three fields sharing the lessons learned from this project. Moreover, examples, such as well performance monitoring and validation, crude blend assessment and assurance and reservoir pressure mapping, which are all being performed in real-time will be presented. In addition, this paper will also illustrate how the integration of I-Field components has effectively helped in optimizing the production from a portfolio of developed reservoirs.