层间非均质砂层石油运移和聚集模拟实验研究

EXPERIMENTAL STUDY ON OIL MIGRATION AND ACCUMULATION IN THE HETEROGENEOUS SAND BEDS OF DIFFERENT POROSITY AND PERMEABILITY

层间非均质砂层石油运移和聚集二维模拟实验证实 ,在各种因素的影响下 ,各砂层的油水分布范围和油水界面存在着很大的差异 ,层间非均质性对砂层的油水分布和含油饱和度起着至关重要的作用。由于层间非均质性的存在 ,可以使高渗透率的砂层为好油层 ,而渗透率相对较低的砂层为差油层 ,甚至为水层。当砂层上倾方向不存在封堵条件时 ,存在着使某些砂层含油范围和含油饱和度发生变化的注油速率临界值。若注油速率小于该临界值 ,无论注油量多大 ,该砂层也不能成为含油层 ,只能成为油水同层或水层 ;反之 ,可以成为含油层。当油气沿高渗透砂体和开启性断层从下部进入上部并充注其侧面的储层时 ,由于浮力的作用 ,油气并不一定进入下部渗透率最大的砂层 ,而是优先进入上部渗透率较高的砂层 ,从而出现渗透率较高的砂层含油饱和度最高 (为含油层 ) ,而渗透率最高的砂层含油饱和度反而较低 (为油水层 )

Simulation experiment on oil migration and accumulation in compartmentalized homogeneous sand beds was conducted by 2\|D experimental model. The results show that there are very difference in oil\|water distribution and oil\|water interface for every sand bed influenced by various factors. The heterogeneity among sand beds has a key effect on the oil\|water distribution and oil saturation in sands. The heterogeneity may cause less or no oil in the sand bed with high porosity and permeability. There is a threshold value of oil input velocity to influence oil\|water distribution and oil saturation of some sand beds with updip sealing. If oil input velocity is less than the threshold value,no matter how much the oil input may be,the sand beds will be saturated by oil and water or else, the sand beds will be saturated by oil. When oil and gas migrate along the sand body with high porosity and permeability or open fault zone from the lower to the upper and inputs the lateral reservoirs,oil prefers to input the upper sand bed with the relative high permeability rather than input the lower sand bed with the highest permeability. It will cause the sand bed with the relative high permeability to have high oil saturation and the sand bed with the highest permeability to have low oil saturation.