The maturity of the giant fields has resulted in a large number of complex operational and reservoir management problems. The reservoirs pressure has substantially dropped as a natural outcome of the accelerate production rhythm sustained by the field during the productive life. The gas-oil contact and oil-water contact have reached the production intervals in many wells. Horizontal wells have proved to be a valid alternative to drain narrow oil columns in this naturally fractured reservoir. To be able to recover the reserves at sufficiently high rates, new ideas and state of the art technologies need to be implemented to innovate the production process, particularly well completions, to maintain the oil production plateau. In the mature fields the objective is to maximize production rates to effectively drain the reserves, while minimizing intervention costs. Intelligent wells will be used to increase productivities and recoveries in a less expensive manner, and to significantly reduce the production of free gas and water. The proposed innovative completion system consists of remotely actuated flow control systems with permanent downhole gauges to permanently monitor the production variables and take actions in real time. This alternative is significantly more effective than the traditional procedure, consisting of selective completions that require expensive subsea interventions to close one zone to open the next one. In this work, the applicability of multi-purpose intelligent completions for highly productive oil reservoirs has been evaluated from both, the productivity and the operational standpoints. Mandrels will be fitted with intelligent gas lift valves that can be operated from the surface, using downhole gauges for reservoir and production surveillance. Design criteria will be discussed in detail to verify that every productivity case is fully optimized.

This paper investigates the use of CO 2 as an EOR solvent for a heavy oil and high permeability naturally fractured reservoir complex in Mexico. The complex is under partial pressure maintenance by Nitrogen injection. First geological features and production performance are analyzed to discern peculiar pressure trends caused by natural depletion and N 2 injection in order to establish the nature of prevailing fluid communication and identify a confined site for CO 2 injection testing. An East Block in the North fields due to its unique dynamic faulting characteristics is found nearly compartmentalized to serve as a suitable site for CO 2 -EOR injection studies. Second, a finely-gridded dual permeability compositional simulation sector model with local grid refinement and boundary flux scheme is constructed and a calibrated 8-component EOS along with full tensor molecular diffusion is implemented to model CO 2 -EOR process mechanisms. CO 2 and N 2 injections into the gas cap at varying rates and huff-n-puff injection in the oil column are simulated. The impact of injection rate is illustrated, where injection of CO 2 at low rates promotes diffusion and is shown to drain more of the matrix oil. The huff-n-puff simulation cases also indicate increased oil recovery and reduced matrix oil saturation by CO 2 injection as compared with N 2 injection due to a combination of oil swelling, reduced oil viscosity and partial miscibility with CO 2 . The paper concludes that the efficiency of CO 2 injections is more pronounced at higher reservoir pressures and with no or less volumes of prior injected N 2 .