A mixed integer optimization formulation for the well scheduling problem on petroleum fields

Abstract

In this paper, we present a novel mixed integer nonlinear (MINLP) model for the daily well scheduling in petroleum fields, where the nonlinear reservoir behaviour, the multiphase flow in wells and constraints from the surface facilities are simultaneously considered. Discrete decisions include the operational status of wells (open or closed), the allocation of wells to manifolds or separators and the allocation of flow lines to separators. Continuous decisions include the well oil rates and the allocation of gas-to-gas lift wells. A solution strategy is proposed involving (i) logic constraints, (ii) inclusion of piecewise linear approximations of each well model and (iii) an outer approximation based algorithm. A number of examples illustrate the applicability of the proposed model and solution strategy where an increase in oil production up to 10% is observed when the results of the proposed method are compared with typical heuristic rules widely applied in practice.