石油二次运移优势路径形成过程实验及机理分析

利用填装玻璃微珠的玻璃管模型,观察静水条件下油在饱含水孔隙介质中靠浮力形成优势运移路径,以及随后沿已形成的路径运移的过程。实验发现,运移的形成过程、路径的形态以及油在已形成的路径内的运移均表现出强烈的非均一性;前缘跳跃、分段运移等现象揭示了运移过程的复杂性。运移路径一旦形成,直到运移结束,其形态和空间展布特征基本一致;再次注入的油仍基本沿原来的路径运移。连续油柱的浮力及该连续油柱所接触到的孔道的毛细管力之间的复杂关系决定了油气非均匀运移路径的形成过程及其形态特征。

EXPERIMENTS ON OIL MIGRATING IN A LIMITED PATHWAY AND THE MECHANISM ANALYSIS

Using glass cylinders packed with glass beads and then saturated with water, a series of experiments was performed to observe, under hydrostatic condition, the details of heterogeneous migrating pathway behaviors during and after migrating. Only the buoyancy was considered as migration force, resulted from the oil column injected into the glass porous media at the beginning. It was observed that once the cluster pathway formed in the medium, it did not, nearly, change during the whole migration. When oil was once more injected into the cylinder where the previous migration finished and left only the residual trace, the newly migrating oil moved strictly along the existing pathway. Some special phenomena, such as haines jumps and snapoff—fragmentation, were observed and analyzed. Based on these observations and understandings, the dynamic relationship between migrating forces and capillary forces in path spatial was considered as key factor, whereas other factors might be regarded as only the influences, acting indirectly on the migrating pathway behaviors.