Abstract: Based on detailed research of the hydrocarbon concentration sealing mechanism, the evaluation index of hydrocarbon concentration sealing ability of caprock by calculating gas diffusive velocity through caprock under the action of supposed hydrocarbon concentration was established by Fick's law, it's also applied to the caprock evaluation of Daqing Placantidine and its western area.This result indicates that this method not only evaluate hydrocarbon concentration sealing ability of caprock quantitatively, but also evaluated caprock in the plane.It is a practicable method for evaluating the hydrocarbon concentration sealing ability of caprock.

Key words: caprock, hydrocarbon concentration, sealing ability, natural gas, diffusion, evaluation, method

摘要： 在深入研究盖层烃浓度封闭机理的基础上,根据费克定律,通过计算在假设外加浓度差作用下通过盖层的扩散速度大小,建立了盖层烃浓度封闭能力评价指标CHSI.应用于大庆长垣及其西部地区盖层评价中,其结果表明该方法不仅可以定量评价盖层的烃浓度封闭能力,而且可以把盖层的评价扩展到平面上。这是一种可行的盖层烃浓度封闭能力评价方法。

关键词: 盖层, 烃浓度, 封闭能力, 天然气, 扩散, 评价, 方法