Abstract: As the degree of hydrocarbon exploration keeps increasing,the uncovered remaining resource is reducing.The key issue interested by petroleum investors and resource evaluators is how to precisely predict the remaining resource in highly and maturely explorative areas.The authors of the paper probe the principle,approach,operating procedure and the existing problems of predicting hydrocarbon resource by reservoir size sequence,the approach is applied to predict the remaining proved reserve at Dongying sag by taking hydrocarbon accumulation system as evaluation unit.The result shows the remaining proved reserve at the sag is 17.03×10⁸ t,there is still great explorative potential,and the hydrocarbon is mainly concentrated in the two accumulation system,i.e.Dongying central belts and Dongying north sag slope.Case study indicates the consequence of resource evaluation is more objective duo to the approach reasonably avoiding the issue of formation mechanism of oil and gas and minimizing subjective influence on the evaluation.

Key words: sequence of oil accumulation size, resources evaluation, Dongying sag, proved reserve, petroleum accumulation system