Abstract: The portfolio optimizing technology is a hot spot of the international petroleum study, while the exploration portfolio system is an important tool to support the implementation of exploration strategies and the planning of exploration allocation of the company. Based on systematic research on portfolio optimization methods, an exploration portfolio system featuring in advanced technologies and perfect function is developed in CNOOC. The system can be used for the economic evaluation of exploration targets, the single-target and multischeme selection, the multi-target synthetic queuing, the zone economic evaluation, and the optimization of exploration portfolio. It helps to realize the integration of the economic evaluation of exploration targets and zones and the research of portfolio and to enrich them. And the evaluating process can be more applied to offshore exploration and development. The system can be widely used in the evaluation of exploration targets, the annual combination of drilling targets, the seasonal drilling allocation, and the rolling planning.

Key words: CNOOC, exploration target, exploration zone, economic evaluation, scheme selection, portfolio