鄂尔多斯盆地陇东地区延长组流体动力作用下的石油运移与聚集特征

Oil migration and accumulation under the influence of fluid dynamics in the Yanchang Formation,eastern Gansu Province,the Ordos Basin

在压实研究基础上,利用等效深度法恢复出早白垩世末鄂尔多斯盆地陇东地区延长组最大埋深时期的过剩压力和相应的油势。对过剩压力在纵向上的分布与试油产量的关系研究表明,距油源区近、过剩压力较小的地区,试油产量高,而日产油量与储层物性的相关性较差,表明过剩压力与石油分布之间的关系更为密切。主成藏期的油势分布表明,平面上油势相对较低的地区是石油运移、聚集的区域,并与现今油藏分布基本吻合。研究认为,在鄂尔多斯盆地陇东地区现今储层低渗的背景下,主成藏期的流体动力仍是油气运移、聚集的主控因素。

Based on the study of compaction,overpressure and oil potential at the deepest burial depth in Early Cretaceous were restored for the Yanchang Formation,eastern Gansu Province,Ordos Basin.We carefully examine the relationship between vertical distribution of overpressure and testing production.The results show that the oil flow is relatively higher where it is close to the oil source and has lower overpressure,indicating that a close relationship between overpressure and oil distribution.Distribution of oil potential in the main period of accumulation shows that oil tends to migrate and accumulate at the lower oil potential area which coincides with current oil distribution.From this study,we believe that,under the condition of low permeability of reservoirs,fluid dynamics in the main period of accumulation is the main controlling factor for oil migration and accumulation.