A ‘smart’ or ‘intelligent’ well is considered one of the most advanced types of nonconventional wells. A typical smart well is equipped with a special completion that has packers or sealing elements which allow partitioning of the wellbore, pressure and temperature sensors and downhole inflow control valves (ICV) installed on the production tubing. The sensors allow continuous monitoring of pressure and temperature while the ICVs provide the flexibility of controlling each branch of a multilateral well independently. A smart well can be either a multilateral well where every lateral is controlled by an ICV or a single bore well where each segment is controlled by an ICV. The advantages of smart wells have been demonstrated in practical applications for both single and multiple reservoir production (non-commingled production). Because of their ability to control production from each lateral or segment through ICV adjustment and manipulation, smart wells can mitigate water production by allocating the optimum production rate and therefore increase the ultimate recovery.
Unlike conventional wells where only surface control is used to determine the optimum production rate, optimization of smart wells requires determining the best combination of ICV settings (ICV configuration) that yields the highest recovery factor and hence profit. In the case of commingled production, laterals or branches are in contact with each other within the immediate vicinity of the reservoir. This adds another dimension to the optimization process as one lateral might affect the production of other laterals (in the case of water breakthrough). Reservoir engineering practices follow two approaches in optimizing oil production from smart wells. These approaches are the reactive approach and the proactive approach. The reactive approach is usually achieved on a trial and error basis, making decisions based on current conditions. A series of production tests is made to determine the best ICV configuration. A portable multiphase flow meter (MPFM) is usually used for a faster decision. The reactive approach mainly corrects for any deviation from the production target; i.e. fast increase in water cut due to heterogeneity. On the other hand, a proactive approach uses an optimization algorithm such as Genetic Algorithm, Simplex, or Swarm Particles to achieve the best ICV configuration that yields maximum oil recovery over a period of time in particular making estimates of future events. The proactive approach also takes advantage of the availability of real time production data which allows for better decisions.
For more information on reactive optimization approach see:
Yeten, B. (2003). Optimum Deployment of Nonconventional Wells. PhD dissertation, Department of Petroleum Engineering, Stanford University, California.
Yeten, B., Durlofsky, L. J., Aziz, K., (2002). Optimization of Smart Well Control, paper SPE/PS-CIM/CHOA 79031 presented at the SPE International Thermal Operations and Heavy Oil Symposium and International Well Technology Conference in Calgary, Alberta, CANADA, 4-7 November