从模拟实验看致密砂岩储层的石油成藏条件

A study on hydrocarbon pooling conditions in tight sandstones through simulated experiments

肖芝华 钟宁宁 黄志龙 姜振学 刘岩

Xiao Zhihua Zhong Ningning Huang Zhilong Jiang Zhenxue Liu Yan

通过不同系列物理模拟实验,对致密砂岩储层中油水倒置成藏的临界地质条件进行了研究.模拟实验结果表明,对于密度约为0.8g/cm的原油,材质相同的各种毛细玻璃管孔喉半径为1.8 mm时,或砂柱中砂体粒径小于0.35～0.40 mm时,即能够产生稳定的油水倒置现象.油水倒置现象的产生与流体浮力和毛细管力之间的力平衡有关,油的密度在油水倒置关系的形成过程中起着比表面张力更为重要的作用.因此,致密砂岩储层油水倒置油藏形成的临界地质条件,主要取决于储油砂层的孔喉半径及其与原油密度之间的关系.

A study on critical geological conditions for oil pooling in inversed oil/water distribution in tight sands is carried out through various serial physical simulated experiments. The result shows that,for crude with density of about 0.8g/cm,a stable inversed oiL/water distribution may occur when the pore throat radius of different capillarity glass tubes made of the same material are 1.8 mm or the grain diameters in sand-column are smaller than 0.35-0.40mm. The phenomenon is thought to be related with the equilibrium between buoyancy (flota-tion) and capillary force and oil density plays a more important role than that of the interfacial tension in the formation of this inversed oil/water distribution. Therefore, it is suggested that the formation of oil pools with inversed water/oil distribution in tight sandstone is subject to the pore radius of reservoir sands and its relationship wish the density of crude oil.

10.11743/ogg20080603