Optimization of Well Oil Rate Allocations in Petroleum Fields

Abstract

Currently, optimization of oil production operations in offshore fields is based mainly on heuristic rules and simulation-like tools with limited optimization features. In this work, we present a novel mixed-integer optimization formulation and an effective solution strategy for daily well operation and gas-lift allocation of integrated oil and gas production facilities in offshore fields considering the nonlinear reservoir behavior, the multiphase flow in pipelines, and surface capacity constraints. On the basis of (i) a degrees of freedom analysis, (ii) well oil rate upper and lower bounds, and (iii) the approximation of each well model with piecewise linear functions, an efficient approximate mixed-integer nonlinear program (MINLP) model is proposed. The resulting model is then solved as a sequence of MILP problems. The accuracy and robustness of the method is investigated by comparing the results of the exact and approximate models, while the performance of the algorithm is illustrated in a number of field examples. The results show that the proposed method achieves an increase in oil production up to 3% when compared with heuristic rules typically applied in practice.