Intelligent wells or intelligent completion systems include remotely operated valves controlling the fluid flow into or out of the different zones in the well. Parameters in the well, like pressure, temperature, fluid flow velocities and void fractions can be observed through wellbore sensors. The immediate benefit of such systems relates to minimizing interventions, caused by critical changes in downhole flow conditions (surprise handling).
Another perspective of intelligent wells is the optimization of the drainage process through a systematic modulation of the downhole valves within a well or cluster of wells. Considerable benefits may be reached by improved production performance or enhanced recovery.
In this perspective the characterization of the reservoir should be regarded as a continuous process, starting in the exploration phase, being refined in the development phase to optimize the production strategy, but also continued during the production phase to enhance the hydrocarbon recovery. A dynamic formation evaluation requires gathering of data throughout the life of the reservoir, enhancing the understanding of the reservoir properties, which is necessary for an optimal production.
One vision of intelligent wells is the operation of the reservoir and the well system like a process plant. To achieve this, the system needs to have “observability” and “controllability”3. The monitoring of reservoir processes and formation parameters, as water/gas-front locations, saturation changes and permeability, is essential to improve the observability. Thus, in order to fully utilize this concept of intelligent wells, the development of permanently installed monitoring systems aiming at a continuous formation evaluation is necessary (Fig. 1).
Fig. 1 Scematics of a multilevel intelligent well with downhole monitoring, estimation of downhole parameters and control of downhole valves based on the measured parameters and a dynamic model of the reservoir.