A multi-objective optimization method of inflow control device configuration

Inflow control device (ICD) restricts flows of certain sections to achieve a uniform push of water oil contact along a horizontal well. The efficiency of ICD depends on its configuration (location, number of nozzles, and nozzle sizes). Traditionally, optimal ICD configurations have been selected using a trial and error approach simulating different configurations. This method is time-consuming and the outcome can be limited by pre-set candidates, thus may result in non-optimal configurations. In this paper, a method involving several optimization objectives is proposed to obtain the optimal ICD configuration, in order to reach an optimal total production before water breakthrough. A flow coupling model (permeation flow – nozzle flow – inner tubing flow) of horizontal wells completed by ICDs is established to calculate the inflow profile and the pressure distribution along the horizontal wellbore. The production rate and the water breakthrough time are the optimization objectives, and the sand control condition (production pressure drawdown < critical pressure drawdown of sanding onset) is taken as one of the constraints of optimization. Then the NSGA-II algorithm is employed to search for the Pareto frontier based on the model of coupled flow. Selected by the TOPSIS method from the Pareto frontier, the optimal ICD configuration ensuring optimal total production and no sanding is acquired. The original data of well A1 in SL oilfield are used for case study. The optimal configuration is compared with single-objective optimization results and open hole completion in terms of production rate and water breakthrough time. By predicting the total productions of different configurations before water breakthrough, we think the optimization method is capable of determining the optimal configuration. This research can provide some theoretical support for the determination of ICD configuration in horizontal wells.