Optimization of multilateral well trajectories using pattern search and genetic algorithms

Multilateral well is a promising technology in developing oil reservoirs. Because this technology may increase the production rate per well and reduce the costs of field development, it is rapidly replacing the old methods. This study uses a three-dimensional line-source model with direct search methods, including pattern search and genetic algorithms to optimize the well trajectories. This method was applied to several cases, with different forms of wells and reservoirs. In all cases, significant improvement was observed in the production rate. Furthermore, the production enhancement using the optimized well trajectories which have curved-paths is compared to the case with linear well trajectories. It was shown that at least a 6% production increase is possible for the curved trajectory well with respect to the well with the constant slope lines. Besides, it was illustrated that the oil production is boosted solely by altering the slope of the well or its laterals along the well path.