利用油柱高度研究仓储层中油的运聚状态——以沾化凹陷为例

Application of Oil Column Height to Research Oil Migration-Accumulation Stage of Storage Layer:Taking Zhanhua Depression as Example

在研究网毯式油气成藏体系仓储层基本特征的基础上,以油气二次运移理论为基础,通过对仓储层中油的运移动力和运移阻力分析,计算仓储层油运移的临界油柱高度,来研究仓储层运移或聚集油的砂体厚度,判断仓储层内油的运聚状态,结果表明:(1)当仓储层的砂体厚度大于临界油柱高度时,仓储层可以起到输导油的作用,当仓储层的砂体厚度小于临界油柱高度时,仓储层不能运移油,起聚集油的作用;(2)临界油柱高度的值不是绝对的,它受孔隙度、埋深等因素的影响,三者之间有相互补偿的关系,临界油柱高度与孔隙度呈负相关关系,与埋深呈正相关关系。通过对临界油柱高度的计算,研究一定埋深下仓储层砂体的厚度和物性的变化,可以判断仓储层内油的运聚状态,确定仓储层起输导油气还是聚集油气的作用,这对于寻找他源次生隐蔽型油气藏,具有一定的指导意义。

On the basis of studying basic characteristics of storage layer in meshwork-carpet type hydrocarbon reservoir system, the critical oil column height of oil migration in storage layer is calculated by using theory of secondary hydrocarbon migration and analyzing migration driving force and resistance force. So oil migrationaccumulation stage in storage layer can be judged by studying sands thickness of oil migration-accumulation. The result shows. （1） The storage layer can transport oil if sands thickness is more than critical oil column height. On the contrary, it can store oil. （2） The size of critical oil column height is influenced by porosity and depth. There is mutual compensation relation among the three. Critical oil column height has a negative relationship with porosity and a positive relationship with depth. By calculating critical oil column height and studying the change of sands thickness and physical property under a certain burial depth, oil migration-accumulation stage in storage layer can be judged. By the method of sands thickness, the transport or storage function of storage layer can be determined effectively. It is meaningful to search for allogenous secondary subtle reservoir.