基于毛细管力的有效储层物性下限判别

有效储层物性下限评价对于油气勘探和开发致关重要。本文在回顾前人相关研究方法的基础上,对储层与围岩介质的物性条件进行了研究,认为有效储层物性下限不是绝对的,而是取决于砂岩与围岩介质物性之间的相对关系,并与埋深具有一定的关系。由此提出了一种新的有效储层物性下限判别方法:利用砂岩储层和围岩介质的毛细管力比值判定有效储层物性下限。有效储层临界条件下的毛细管力比值随埋深增加表现出逐渐增大趋势,其物性下限也随埋深具有一定的变化规律。根据该方法在珠一坳陷深部古近系储层中识别出的有效储层与测井解释成果基本吻合。该方法对于优选油气勘探目标具有一定的指导意义。

Physical Threshold of Effective Reservoir Evaluation Based on Capillary Pressure

It is important to determine the physical threshold of effective reservoirs for hydrocarbon exploration. The physical property of reservoir sandstones and surrounding rocks is used to study in this paper. It is found that the criterion of effective reservoirs is not constant and unconditional, while controlled by the relative physical property between reservoir sandstones and surrounding rocks, having a relationship with burial depths. A new evaluation method is proposed in this paper, in which the ratios of capillary pressure of sandstone reservoirs to surrounding rocks are used to determine the threshold of effective reservoirs. The ratios on the critical conditions become larger with increasing depth, which means the threshold of effective reservoirs has a certain relationship with burial depth. The physical property of effective reservoir with certain depth must exceed the threshold with the same depth, otherwise it cannot accumulate oil or gas. The new method is applied to evaluate the Paleogene reservoirs of Zhu 1 Depression, and the effective reservoirs recognized by the new method coincide well with the well logging results. The new method would be significant for petroleum accumulation and distribution prediction.