三角洲前缘砂体中石油二次运移与聚集过程物理模拟及结果分析

物理模拟是阐明油气二次运移的效率、机理及其在圈闭中的聚集过程的一个重要途径。针对三角洲前缘砂体这种最有利于油气藏形成的砂体类型,设计了石油在多层均质砂层构成的指状非均质储层运移物理模拟实验模型,来考查石油二次运移的通道、效率和速率。实验表明,石油二次运移的通道十分有限,石油在砂状体的最凸出部位进入储层后,主要沿指状砂体中央有限的通道（约5cm宽）由油源向圈闭运移,而且运移速度很快,约1．4cm/min,通道上含油饱和度较低,约16％。当到达顶部的封闭层后,石油开始聚集成藏。这就表明了石油二次运移、聚集成藏具有沿着有限通道快速、高效运移、聚集成藏的特征,揭示了石油运移“高速公路”的存在和油藏形成与大量排烃同步这一成藏规律。

Physical Modeling of Secondary Oil Migration and Accumulation in Deltaic Sandstone Reservoir and Its Result Analysis

Physical modeling is an effective way to clarify the efficiency, process and mechanism of secondary oil migration and accumulation. Based on the deltaic front sandstone, which favors oil and gas pool forming, this paper designs and constructs a physical model of secondary oil migration and accumulation in finger-shape non-homogeneous reservoirs, which are composed of multi-layers of homogeneous reservoir, in order to research the path, efficiency and rate. The results of the experiment indicated that the path of secondary oil migration is quite limited. When oil entered into the reservoir from the tip position of finger-shape sandstone body, it mainly migrated to the trap along the middle finite path (about 5 cm wide) from its source. When the rate of migration was very fast, about 1.4 cm/min, and the saturation in the path was about 16%, and after it got to the seal layer, oil began to be accumulated. This implies that secondary oil migration and accumulation take on the characteristics along the finite path, fast and efficient migration and accumulation, and also reveals the "highway" of secondary oil migration exists and the rule of oil pool forming is synchronized with oil volume expelling.