Oil and gas projects are ruled by risks, uncertainties and also opportunities within their complex decision-making processes. In this work, a decision-making framework for the conceptual design and project evaluations in the oil and gas industry is presented. The framework is based on game theory where the strategic set of decisions are generated by a binary genetic algorithm. The proposed framework solves simultaneously a multi-objective and multi-level decision-making problem. The framework is validated using a well-known pressure vessel design case. In addition three study cases were defined in order to analyze the impact of multiple objectives on the conceptual design of pressure vessel. The comparison between the obtained results and the reported results for the pressure vessel design validates the confidence of the proposed framework. Furthermore the evaluation of the proposed framework showed that the outcomes of the conceptual process design varies depending on the considered objectives. As expected, more realistic outcomes are obtained when an integrated framework of decision-making includes the strategic costs from the conceptual design phase. However, the objective functions relies on soft information with large uncertainties, particularly in the design phase. Therefore uncertainties might be included in order to improve the outcomes. (C) 2012 Elsevier Ltd. All rights reserved.