饶阳凹陷马西断层封闭性评价

Study on Fault Sealing of the Maxi Fault in the Raoyang Depression

断层封闭性研究对于确定油气藏的分布具有重要意义。针对断层两盘的岩性配置关系、泥岩涂抹分析、断裂充填物泥质含量分析、断层活动期与油气运移成藏期的配置和断面力学性质等影响因素的特征,对饶阳凹陷马西断层的断层封闭性进行分析,最后应用综合评价方法进行综合判断。结果表明,古近纪中晚期马西断层活动强烈,封闭性较差,正好与本区的油气运移成藏期相配合,为油藏的形成提供了有效的运移通道;新近纪至今,断层长期停止活动,且其封闭性表现出"上好下差"的特点,对本区沙河街组油藏的保存具有重要意义。

Faults can become pathways for migration of hydrocarbons,but they also can be barriers to reservoirs in different geologic epochs.Hence,it is important to study fault sealing performance to determine the distribution of reservoirs.Several factors can influence fault sealing performance,namely,the lithologic associations on two sides of a given fault,mudstone-smearing,the relationship between fault-movement periods and hydrocarbon migration intervals,and the stress of fracture surfaces.This study examined these factors for the fault sealing performance of the Maxi fault in the Raoyang depression.Fault sealing performance was evaluated using the synthesized evaluation method.Results show that the Maxi Fault grew actively in the Middle-late Cenozoic.Fault sealing was poor in this period,while hydrocarbon migration was at a peak during this interval.Thus,it appears the fault became a pathway for hydrocarbon migration.After that,the Maxi fault stopped growing for a long time.At the same time,fault sealing became more dominant,showed the specialties as upperbetter and lower-worse.This situation was beneficial in creating a petroleum reservoir in Shahejie strata.However,petroleum could not be trapped in the foot wall of the Maxi Fault.