石油二次运移优势路径影响因素及形成动力学条件

Effect factors and dynamic conditions in the formation of preferable paths in oil secondary migration

利用物理模拟实验和基于逾渗理论的油气运聚模拟方法对石油二次运移优势路径形成影响因素进行模拟并探讨优势路径形成的动力学条件。研究表明,优势路径具有油运移前缘只沿一个或少数几个方向向上指进运移、运移路径窄及通过该路径油运移量较大的基本特征;模型颗粒表面亲水性越好、模型颗粒粒度越大、油水密度差越大、界面张力越小、孔喉直径越大、运移动力越小,油越易出现优势运移路径。系统的浮力与黏滞力竞争及毛细管力与黏滞力竞争中前者均处于优势是运移优势路径形成的动力学条件,且竞争优势越明显,油运移越易形成优势运移路径。该研究成果有助于了解和认识油气二次运移规律并为盆地尺度的油气运移模拟提供基础理论依据。

Using the hydrocarbon migration modeling methods based on the percolation theory,in combination with physical experiments,we simulated the effect factors on and discussed dynamic conditions in forming preferable path for secondary migration of oil.The preferable path has the basic features that the front of migrating oil has only one or a few of upward finger advance,the migration path is narrow,and through the preferable path the migration oil amount is larger.The migration pattern may tend to form preferable path of secondary migration when the grain surface wettability gets better,the grain size and the density difference between oil and water get bigger,the interfacial tension get smaller,the radius of pores and throats get bigger,and the migration force get smaller.During the buoyancy competing with viscous force and the capillary force competing with viscous force,if the former is dominant,the dynamic conditions for preferable path could be fulfilled.And the more obvious the dominance is,the more easily preferable path occurs.This study may shed some light on migration in nature and offer academic basis for simulation in sedimentary basins.